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44 results on '"Dom Walton"'

1. The Chameleon on the branches: spectral state transition and dips in NGC 247 ULX-1

Author

Fabio Pintore, M. Del Santo, A. Robba, P. Kosec, E. Ambrosi, Erin Kara, Antonino D'Ai, Dom Walton, Ciro Pinto, A. C. Fabian, G. Rodriguez-Castillo, Matthew J. Middleton, F. Fürst, Timothy P.L. Roberts, Didier Barret, Roberto Soria, W. N. Alston, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), ITA, USA, GBR, FRA, and ESP

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Photosphere, Absorption spectroscopy, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Flux, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Occultation, X-rays: individual: NGC 247 ULX-1, Spectral line, Luminosity, X-rays: binaries, Space and Planetary Science, 0103 physical sciences, Thermal, Black-body radiation, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Soft Ultra-Luminous X-ray (ULXs) sources are a subclass of the ULXs that can switch from a supersoft spectral state, where most of the luminosity is emitted below 1 keV, to a soft spectral state with significant emission above 1 keV. In a few systems, dips have been observed. The mechanism behind this state transition and the dips nature are still debated. To investigate these issues, we obtained a long XMM-Newton monitoring campaign of a member of this class, NGC 247 ULX-1. We computed the hardness-intensity diagram for the whole dataset and identified two different branches: the normal branch and the dipping branch, which we study with four and three hardness-intensity resolved spectra, respectively. All seven spectra are well described by two thermal components: a colder ($kT_{\rm bb}$ $\sim$ 0.1-0.2 keV) black-body, interpreted as emission from the photo-sphere of a radiatively-driven wind, and a hotter ($kT_{\rm disk}$ $\sim$ 0.6 keV) multicolour disk black-body, likely due to reprocessing of radiation emitted from the innermost regions. In addition, a complex pattern of emission and absorption lines has been taken into account based on previous high-resolution spectroscopic results. We studied the evolution of spectral parameters and the flux of the two thermal components along the two branches and discuss two scenarios possibly connecting the state transition and the dipping phenomenon. One is based on geometrical occultation of the emitting regions, the other invokes the onset of a propeller effect., 13 pages, accepted by MNRAS on 2021/08/16

Published
2021
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2. Discovery of thermonuclear (Type I) X-ray bursts in the X-ray binary Swift J1858.6–0814 observed with NICER and NuSTAR

Author

N. Castro Segura, Francesco Tombesi, Tod E. Strohmayer, Zaven Arzoumanian, Jon M. Miller, Keith C. Gendreau, A. C. Albayati, D. J. K. Buisson, Deepto Chakrabarty, Poshak Gandhi, Dom Walton, Tolga Guver, Diego Altamirano, Sebastien Guillot, John A. Tomsick, C. Malacaria, F. M. Vincentelli, Ron Remillard, Jeroen Homan, Jeremy Hare, Jiachen Jiang, Gaurava K. Jaisawal, M. Ozbey Arabaci, Peter Bult, G. C. Mancuso, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Ciencias Astronómicas, Accretion, bursts [X-rays], Ciencias Físicas, Astrophysics::High Energy Astrophysical Phenomena, X-ray binary, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Compact star, 01 natural sciences, Luminosity, purl.org/becyt/ford/1 [https], X-rays: binaries, stars: neutron, accretion, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, ACCRETION, ACCRETION DISCS, X-rays: bursts, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Accretion (meteorology), Settore FIS/05, 010308 nuclear & particles physics, neutron [Stars], Astronomy and Astrophysics, purl.org/becyt/ford/1.3 [https], Radius, Light curve, accretion discs, Astronomía, Neutron star, Amplitude, Space and Planetary Science, accretion, accretion discs, binaries [X-rays], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - High Energy Astrophysical Phenomena, CIENCIAS NATURALES Y EXACTAS, Accretion discs
Abstract

Swift J1858.6-0814 is a recently discovered X-ray binary notable for extremely strong variability (by factors $>100$ in soft X-rays) in its discovery state. We present the detection of five thermonuclear (Type I) X-ray bursts from Swift J1858.6-0814, implying that the compact object in the system is a neutron star. Some of the bursts show photospheric radius expansion, so their peak flux can be used to estimate the distance to the system. The peak luminosity, and hence distance, can depend on several system parameters; for the most likely values, a high inclination and a helium atmosphere, $D=12.8_{-0.6}^{+0.8}$ kpc, although systematic effects allow a conservative range of $9-18$ kpc. Before one burst, we detect a QPO at $9.6\pm0.5$ mHz with a fractional rms amplitude of $2.2\pm0.2$% ($0.5-10$ keV), likely due to marginally stable burning of helium; similar oscillations may be present before the other bursts but the light curves are not long enough to allow their detection. We also search for burst oscillations but do not detect any, with an upper limit in the best case of 15% fractional amplitude (over $1-8$ keV). Finally, we discuss the implications of the neutron star accretor and this distance on other inferences which have been made about the system. In particular, we find that Swift J1858.6-0814 was observed at super-Eddington luminosities at least during bright flares during the variable stage of its outburst., 14 pages, 8 figures, 2 tables, MNRAS accepted

Published
2020
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3. XMM-Newton campaign on the ultraluminous X-ray source NGC 247 ULX-1: outflows

Author

Timothy P.L. Roberts, Antonino D'Ai, M. Del Santo, William Alston, F. Fuerst, Roberto Soria, Dom Walton, A. C. Fabian, Matthew J. Middleton, A Robba, E. Ambrosi, P. Kosec, Ciro Pinto, Fabio Pintore, Hannah P. Earnshaw, Didier Barret, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Ultraluminous X-ray source, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, accretion discs, Spectral line, X-rays: individual: NGC 247 ULX-1, Blueshift, Neutron star, X-rays: binaries, Radiation pressure, accretion, Space and Planetary Science, Close relationship, 0103 physical sciences, Outflow, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Line (formation)
Abstract

Most ULXs are believed to be powered by super-Eddington accreting neutron stars and, perhaps, black holes. Above the Eddington rate the disc is expected to thicken and to launch powerful winds through radiation pressure. Winds have been recently discovered in several ULXs. However, it is yet unclear whether the thickening of the disc or the wind variability causes the switch between the classical soft and supersoft states observed in some ULXs. In order to understand such phenomenology and the overall super-Eddington mechanism, we undertook a large (800 ks) observing campaign with XMM-Newton to study NGC 247 ULX-1, which shifts between a supersoft and classical soft ULX state. The new observations show unambiguous evidence of a wind in the form of emission and absorption lines from highly-ionised ionic species, with the latter indicating a mildly-relativistic outflow (-0.17c) in line with the detections in other ULXs. Strong dipping activity is observed in the lightcurve and primarily during the brightest observations, which is typical among soft ULXs, and indicates a close relationship between the accretion rate and the appearance of the dips. The latter is likely due to a thickening of the disc scale-height and the wind as shown by a progressively increasing blueshift in the spectral lines., 18 pages, 16 figures, accepted for publication in MNRAS

Published
2021
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4. Long-term pulse period evolution of the ultra-luminous X-ray pulsar NGC 7793 P13

Author

Timothy P.L. Roberts, Didier Barret, Natalie A. Webb, A. C. Fabian, Joern Wilms, F. Fürst, Ciro Pinto, D. Stern, Katja Pottschmidt, Peter Kretschmar, Matteo Bachetti, Matthew J. Middleton, Hannah P. Earnshaw, Andy Ptak, M. Heida, Dom Walton, Murray Brightman, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), ITA, USA, GBR, FRA, DEU, ESP, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Ephemeris, 01 natural sciences, Pulse period, stars: neutron, X-rays: binaries, Flux (metallurgy), Pulsar, accretion, 0103 physical sciences, 010306 general physics, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Accretion (meteorology), accretion disks, Astronomy and Astrophysics, Orbital period, pulsars: individual: NGC 7793 P13, Term (time), Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], X-ray pulsar
Abstract

Ultra-luminous X-ray pulsars (ULXPs) provide a unique opportunity to study super-Eddington accretion. We present the results of a monitoring campaign of ULXP NGC 7793 P13. Over our four-year monitoring campaign with Swift, XMM-Newton, and NuSTAR, we measured a continuous spin-up with $\dot P$ ~ -3.8e-11 s/s. The strength of the spin-up is independent of the observed X-ray flux, indicating that despite a drop in observed flux in 2019, accretion onto the source has continued at largely similar rates. The source entered an apparent off-state in early 2020, which might have resulted in a change in the accretion geometry as no pulsations were found in observations in July and August 2020. We used the long-term monitoring to update the orbital ephemeris and the periodicities seen in both the observed optical/UV and X-ray fluxes. We find that the optical/UV period is very stable over the years, with $P_\text{UV}$ = 63.75 (+0.17, -0.12) d. The best-fit orbital period determined from our X-ray timing results is 64.86 +/- 0.19 d, which is almost a day longer than previously implied, and the X-ray flux period is 65.21+/- 0.15 d, which is slightly shorter than previously measured. The physical origin of these different flux periods is currently unknown. We study the hardness ratio to search for indications of spectral changes. We find that the hardness ratios at high energies are very stable and not directly correlated with the observed flux. At lower energies we observe a small hardening with increased flux, which might indicate increased obscuration through outflows at higher luminosities. We find that the pulsed fraction is significantly higher at low fluxes. This seems to imply that the accretion geometry already changed before the source entered the deep off-state. We discuss possible scenarios to explain this behavior, which is likely driven by a precessing accretion disk., Comment: 10 pages, 6 figures, accepted for publication in A&A

Published
2021
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5. Thermal stability of winds driven by radiation pressure in super-Eddington accretion discs

Author

Jan-Uwe Ness, Matthew J. Middleton, Roberto Soria, P. Kosec, Ciro Pinto, Missagh Mehdipour, Timothy P.L. Roberts, Dom Walton, Andrew C. Fabian, and Matteo Guainazzi

Subjects
Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Photoionization, 01 natural sciences, Wind speed, symbols.namesake, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Accretion (astrophysics), Neutron star, Radiation pressure, Space and Planetary Science, Eddington luminosity, symbols, Spectral energy distribution, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Computational Physics
Abstract

Ultraluminous X-ray sources (ULXs) are mainly powered by accretion in neutron stars or stellar-mass black holes. Accreting at rates exceeding the Eddington limit by factors of a few up to hundreds, radiation pressure is expected to inflate the accretion disc, and drive fast winds that have in fact been observed at significant fractions of the speed of light. Given the super-Eddington luminosity, the accretion disc will be thicker than in sub-Eddington accretors such as common active galactic nuclei and X-ray binaries, leading to a different spectral energy distribution and, possibly, a different thermal status of the wind. Here we show the first attempt to calculate the photoionization balance of the winds driven by strong radiation pressure in thick discs with a focus on ULXs hosting black holes or non-magnetic neutron stars. We find that the winds are generally in thermally stable equilibrium, but long-term variations in the accretion rate and the inclination due to precession may have significant effects on the wind appearance and stability. Our model trends can explain the observed correlation between the spectral residuals around 1 keV and the ULX spectral state. We also find a possible correlation between the spectral hardness of the ULX, the wind velocity and the ionization parameter in support of the general scenario., Comment: 17 pages, 9 figures, 5 tables, accepted for publication in MNRAS

Published
2019
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6. MAXI J1820+070 with NuSTAR I. An increase in variability frequency but a stable reflection spectrum: coronal properties and implications for the inner disc in black hole binaries

Author

Didier Barret, Poshak Gandhi, John A. Tomsick, K. K. Madsen, Michael Parker, Erin Kara, Douglas J. K. Buisson, Jon M. Miller, Dom Walton, Javier A. García, Felix Fürst, Aarran W. Shaw, A. C. Fabian, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, black hole physics, FOS: Physical sciences, Astrophysics, Electron, 01 natural sciences, X-rays: binaries, accretion, Accretion disc, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Effective radius, Electron pair, 010308 nuclear & particles physics, Astronomy and Astrophysics, accretion discs, Accretion (astrophysics), High flux, Space and Planetary Science, Reflection spectrum, Coronal plane, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

MAXI J1820+070 (optical counterpart ASASSN-18ey) is a black hole candidate discovered through its recent very bright outburst. The low extinction column and long duration at high flux allow detailed measurements of the accretion process to be made. In this work, we compare the evolution of X-ray spectral and timing properties through the initial hard state of the outburst. We show that the inner accretion disc, as measured by relativistic reflection, remains steady throughout this period of the outburst. Nevertheless, subtle spectral variability is observed, which is well explained by a change in coronal geometry. However, characteristic features of the temporal variability - low-frequency roll-over and QPO frequency - increase drastically in frequency, as the outburst proceeds. This suggests that the variability timescales are governed by coronal conditions rather than solely by the inner disc radius. We also find a strong correlation between X-ray luminosity and coronal temperature. This can be explained by electron pair production with a changing effective radius and a non-thermal electron fraction of ~20%., Re-submitted to MNRAS after reviewers comments. 14 pages, 14 figures

Published
2019
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7. The remarkable X-ray variability of IRAS 13224-3809

Author

Christopher S. Reynolds, Matthew J. Middleton, A. C. Fabian, Edward M. Cackett, Dan R. Wilkins, Erin Kara, G. Miniutti, Andrew J. Young, Dom Walton, Ciro Pinto, D. J. K. Buisson, Jiachen Jiang, B. De Marco, Michal Dovciak, Anne M. Lohfink, William Alston, Phil Uttley, Michael Parker, Luigi C. Gallo, Abderahmen Zogbhi, Alston, William [0000-0003-2658-6559], Fabian, Andrew [0000-0002-9378-4072], Parker, Michael [0000-0002-8466-7317], Pinto, Ciro [0000-0003-2532-7379], Walton, Dominic [0000-0001-5819-3552], Reynolds, Christopher [0000-0002-1510-4860], Jiang, Jiachen [0000-0002-9639-4352], Apollo - University of Cambridge Repository, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Normalization (statistics), Seyfert [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Flux, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, galaxies: individual: IRAS 13224-3809, 01 natural sciences, 0103 physical sciences, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Accretion (meteorology), 010308 nuclear & particles physics, individual: IRAS 13224-3809 [Galaxies], Spectral density, Static timing analysis, Astronomy and Astrophysics, Light curve, Galaxy, galaxies: Seyfert, galaxies [X-rays], Black hole, X-rays: galaxies, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present a detailed X-ray timing analysis of the highly variable NLS1 galaxy, IRAS 13224-3809. The source was recently monitored for 1.5 Ms with XMM-Newton which, combined with 500 ks archival data, makes this the best studied NLS1 galaxy in X-rays to date. We apply standard time- and Fourier-domain in order to understand the underlying variability process. The source flux is not distributed lognormally, as would be expected for accreting sources. The first non-linear rms-flux relation for any accreting source in any waveband is found, with $\mathrm{rms} \propto \mathrm{flux}^{2/3}$. The light curves exhibit significant strong non-stationarity, in addition to that caused by the rms-flux relation, and are fractionally more variable at lower source flux. The power spectrum is estimated down to $\sim 10^{-7}$ Hz and consists of multiple peaked components: a low-frequency break at $\sim 10^{-5}$ Hz, with slope $\alpha < 1$ down to low frequencies; an additional component breaking at $\sim 10^{-3}$ Hz. Using the high-frequency break we estimate the black hole mass $M_\mathrm{BH} = [0.5-2] \times 10^{6} M_{\odot}$, and mass accretion rate in Eddington units, $\dot m_{\rm Edd} \gtrsim 1$. The non-stationarity is manifest in the PSD with the normalisation of the peaked components increasing with decreasing source flux, as well as the low-frequency peak moving to higher frequencies. We also detect a narrow coherent feature in the soft band PSD at $0.7$ mHz, modelled with a Lorentzian the feature has $Q \sim 8$ and an $\mathrm{rms} \sim 3$ %. We discuss the implication of these results for accretion of matter onto black holes., Comment: Accepted to MNRAS. 19 pages, 17 figures

Published
2019
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8. Ionized emission and absorption in a large sample of ultraluminous X-ray sources

Author

Christopher S. Reynolds, Ciro Pinto, I. Valtchanov, A. C. Fabian, P. Kosec, Michael Parker, Matteo Guainazzi, Erin Kara, and Dom Walton

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, education.field_of_study, Absorption spectroscopy, Accretion (meteorology), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Spectral density, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Emission spectrum, Spectral resolution, education, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract

Most Ultraluminous X-ray sources (ULXs) are thought to be powered by super-Eddington accretion onto stellar-mass compact objects. Accretors in this extreme regime are naturally expected to ionise copious amounts of plasma in their vicinity and launch powerful radiation-driven outflows from their discs. High spectral resolution X-ray observations (with RGS gratings onboard XMM-Newton) of a few ULXs with the best datasets indeed found complex line spectra and confirmed such extreme (0.1-0.3c) winds. However, a search for plasma signatures in a large ULX sample with a rigorous technique has never been performed, thereby preventing us from understanding their statistical properties such as the rate of occurrence, to constrain the outflow geometry and its duty cycle. We developed a fast method for automated line detection in X-ray spectra and applied it to the full RGS ULX archive, rigorously quantifying the statistical significance of any candidate lines. Collecting the 135 most significant features detected in 89 observations of 19 objects, we created the first catalogue of spectral lines detected in soft X-ray ULX spectra. We found that the detected emission lines are concentrated around known rest-frame elemental transitions and thus originate from low-velocity material. The absorption lines instead avoid these transitions, suggesting they were imprinted by blueshifted outflows. Such winds therefore appear common among the ULX population. Additionally, we found that spectrally hard ULXs show fewer line detections than soft ULXs, indicating some difference in their accretion geometry and orientation, possibly causing over-ionisation of plasma by the harder spectral energy distributions of harder ULXs., Accepted for publication in MNRAS. 22 pages, 6 figures and 3 tables

Published
2021
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9. Quasi-periodic dipping in the ultraluminous X-ray source, NGC 247 ULX-1

Author

A. C. Fabian, Timothy P.L. Roberts, R. Sathyaprakash, A. Robba, P. Kosec, Matthew J. Middleton, Hannah P. Earnshaw, Ciro Pinto, Erin Kara, Fabio Pintore, Felix Fuerst, Dom Walton, W. N. Alston, Antonino D'Ai, M. Del Santo, Didier Barret, E. Ambrosi, Michael Parker, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Ultraluminous X-ray source, Stellar mass, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Compact star, 01 natural sciences, Spectral line, symbols.namesake, X-rays: binaries, accretion, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Accretion (meteorology), 010308 nuclear & particles physics, Astronomy and Astrophysics, Light curve, accretion discs, X-rays: individual: NGC 247 ULX-1, Neutron star, Space and Planetary Science, Eddington luminosity, symbols, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Most ultraluminous X-ray sources (ULXs) are believed to be stellar mass black holes or neutron stars accreting beyond the Eddington limit. Determining the nature of the compact object and the accretion mode from broadband spectroscopy is currently a challenge, but the observed timing properties provide insight into the compact object and details of the geometry and accretion processes. Here we report a timing analysis for an 800 ks XMM-Newton campaign on the supersoft ultraluminous X-ray source, NGC 247 ULX-1. Deep and frequent dips occur in the X-ray light curve, with the amplitude increasing with increasing energy band. Power spectra and coherence analysis reveals the dipping preferentially occurs on $\sim 5$ ks and $\sim 10$ ks timescales. The dips can be caused by either the occultation of the central X-ray source by an optically thick structure, such as warping of the accretion disc, or from obscuration by a wind launched from the accretion disc, or both. This behaviour supports the idea that supersoft ULXs are viewed close to edge-on to the accretion disc., Comment: Accepted MNRAS version following minor comments. 8 pages, 6 figures

Published
2021
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10. A New Transient Ultraluminous X-ray Source in NGC 7090

Author

George B. Lansbury, V. Rana, Timothy P.L. Roberts, P. A. Evans, D. Stern, Fiona A. Harrison, Andrew C. Fabian, Ruben Salvaterra, Matthew J. Middleton, Dom Walton, Brian W. Grefenstette, X. Song, Hannah P. Earnshaw, M. Heida, Felix Fürst, Murray Brightman, Matteo Bachetti, G. A. Rodríguez Castillo, G. L. Israel, Sean N. Pike, ITA, USA, GBR, and ESP

Subjects
Ultraluminous X-ray source, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), education.field_of_study, Accretion (meteorology), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galaxy, Spectral line, Luminosity, Black hole, Pulsar, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, education, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We report on the discovery of a new, transient ultraluminous X-ray source (ULX) in the galaxy NGC 7090. This new ULX, which we refer to as NGC 7090 ULX3, was discovered via monitoring with $Swift$ during 2019-20, and to date has exhibited a peak luminosity of $L_{\rm{X}} \sim 6 \times 10^{39}$ erg s$^{-1}$. Archival searches show that, prior to its recent transition into the ULX regime, ULX3 appeared to exhibit a fairly stable luminosity of $L_{\rm{X}} \sim 10^{38}$ erg s$^{-1}$. Such strong long-timescale variability may be reminiscent of the small population of known ULX pulsars, although deep follow-up observations with $XMM$-$Newton$ and $NuSTAR$ do not reveal any robust X-ray pulsation signals. Pulsations similar to those seen from known ULX pulsars cannot be completely excluded, however, as the limit on the pulsed fraction of any signal that remains undetected in these data is $\lesssim$20\%. The broadband spectrum from these observations is well modelled with a simple thin disc model, consistent with sub-Eddington accretion, which may instead imply a moderately large black hole accretor ($M_{\rm{BH}} \sim 40 ~ M_{\odot}$). Similarly, though, more complex models consistent with the super-Eddington spectra seen in other ULXs (and the known ULX pulsars) cannot be excluded given the limited signal-to-noise of the available broadband data. The nature of the accretor powering this new ULX therefore remains uncertain., 11 pages, 7 figures; accepted for publication in MNRAS

Published
2020

11. MAXI J1820+070 with NuSTAR - II. Flaring during the hard to soft state transition with a long soft lag

Author

Aarran W. Shaw, Douglas J. K. Buisson, Michael Parker, Erin Kara, Poshak Gandhi, John A. Tomsick, Dom Walton, J. Wang, and A. C. Fabian

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Jet (fluid), Accretion (meteorology), 010308 nuclear & particles physics, Lag, Astrophysics::High Energy Astrophysical Phenomena, Phase (waves), Flux, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Spectral line, law.invention, Settling, Space and Planetary Science, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Flare
Abstract

We continue the analysis of NuSTAR data from the recent discovery outburst of MAXI J1820+070 (optical counterpart ASASSN-18ey), focussing on an observation including unusual flaring behaviour during the hard to soft state transition, which is a short phase of outbursts and so comparatively rarely observed. Two plateaus in flux are separated by a variable interval lasting ~10 ks, which shows dipping then flaring stages. The variability is strongest (with fractional variability up to $F_{\rm Var}\sim10\%$) at high energies and reduces as the contribution from disc emission becomes stronger. Flux-resolved spectra show that the variability is primarily due to the power law flux changing. We also find a long soft lag of the thermal behind the power law emission, which is $20_{-1.2}^{+1.6}$ s during the flaring phase. The lag during the dipping stage has a different lag-energy spectrum, which may be due to a wave passing outwards through the disc. Time resolved spectral fitting suggests that the lag during the flaring stage may be due to the disc re-filling after being disrupted to produce the power law flare, perhaps related to the system settling after the jet ejection which occurred around 1 day before. The timescales of these phenomena imply a low viscosity parameter, $\alpha\sim10^{-3}$, for the inner region of the disc., Comment: MNRAS, resubmitted after minor revision. 12 pages, 10 figures, 1 table

Published
2020

12. Discovery of a soft X-ray lag in the ultraluminous X-ray source NGC 1313 X-1

Author

Claude R. Canizares, A. C. Fabian, Lian Tao, Natalie A. Webb, Ciro Pinto, Didier Barret, Murray Brightman, Felix Fürst, P. Kosec, Roberto Soria, Hannah P. Earnshaw, Matteo Bachetti, Erin Kara, Matthew J. Middleton, William Alston, Dom Walton, Timothy P.L. Roberts, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
Ultraluminous X-ray source, Lag, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, X-rays: binaries, accretion, 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Covariance, accretion discs, Accretion (astrophysics), Amplitude, Space and Planetary Science, X-rays: individual: NGC 1313 X-1, Outflow, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Ultraluminous X-ray Sources (ULXs) provide a unique opportunities to probe the geometry and energetics of super-Eddington accretion. The radiative processes involved in super-Eddington accretion are not well understood, and so studying correlated variability between different energy bands can provide insights into the causal connection between different emitting regions. We present a spectral-timing analysis of NGC 1313 X-1 from a recent XMM-Newton campaign. The spectra can be decomposed into two thermal-like components, the hotter of which may originate from the inner accretion disc, and the cooler from an optically thick outflow. We find correlated variability between hard (2-10 keV) and soft (0.3-2 keV) bands on kilosecond timescales, and find a soft lag of ~150 seconds. The covariance spectrum suggests that emission contributing to the lags is largely associated with the hotter of the two thermal-like components, likely originating from the inner accretion flow. This is only the third ULX to exhibit soft lags. The lags range over three orders of magnitude in amplitude, but all three are ~5 to ~20 percent of the corresponding characteristic variability timescales. If these soft lags can be understood in the context of a unified picture of ULXs, then lag timescales may provide constraints on the density and extent of radiatively-driven outflows., Re-submitted to MNRAS after minor revisions, 7 pages, 5 figures

Published
2020
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13. Detection of a variable ultrafast outflow in the narrow-line Seyfert 1 galaxy PG 1448+273

Author

Christopher S. Reynolds, Michael Parker, Dom Walton, P. Kosec, Abderahmen Zoghbi, Andrew C. Fabian, and Ciro Pinto

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Supermassive black hole, Active galactic nucleus, Accretion (meteorology), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galaxy, Spectral line, Space and Planetary Science, Ionization, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Outflow, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract

Relativistically blueshifted absorption features of highly ionised ions, the so-called ultra-fast outflows (UFOs), have been detected in the X-ray spectra of a number of accreting supermassive black holes. If these features truly originate from accretion disc winds accelerated to more than 10 per cent of the speed of light, their energy budget is very significant and they can contribute to or even drive galaxy-scale feedback from active galactic nuclei (AGN). However, the UFO spectral features are often weak due to high ionisation of the outflowing material, and the inference of the wind physical properties can be complicated by other spectral features in AGN such as relativistic reflection. Here we study a highly accreting Narrow Line Seyfert 1 galaxy PG 1448+273. We apply an automated, systematic routine for detecting outflows in accreting systems and achieve an unambiguous detection of a UFO in this AGN. The UFO absorption is observed in both soft and hard X-ray bands with the XMM-Newton observatory. The velocity of the outflow is (26900 +- 600) km/s (~0.09c), with an ionisation parameter of log ({\xi} / erg cm s^-1)=4.03_{-0.08}^{+0.10} and a column density above 10^23 cm^-2. At the same time, we detect weak warm absorption features in the spectrum of the object. Our systematic outflow search suggests the presence of further multi-phase wind structure, but we cannot claim a significant detection considering the present data quality. The UFO is not detected in a second, shorter observation with XMM-Newton, indicating variability in time, observed also in other similar AGN., Comment: Accepted for publication in MNRAS. 14 pages, 11 figures, 1 table

Published
2020
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14. Hunt for Pulsating Ultraluminous X-ray Sources

Author

X. Song, George B. Lansbury, Dom Walton, Andrew C. Fabian, Hannah P. Earnshaw, Phil Evans, and Timothy P.L. Roberts

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Pulsar, Space and Planetary Science, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Order of magnitude
Abstract

Motivated by the recent discoveries that six Ultraluminous X-ray Sources (ULXs) are powered by highly super-Eddington X-ray pulsars, we searched for additional pulsating ULX (PULX) candidates by identifying sources that exhibit long-term flux variability of at least an order of magnitude (a common feature seen in the 6 known PULXs, which may potentially be related to transitions to the propeller regime). Expanding on previous studies, we used the available fluxes from XMM-Newton, Swift and Chandra, along with carefully computed upper limits in cases of a non-detection, to construct long-term lightcurves for a sample of 296 ULXs selected from the XMM-Newton archive. Among these 296, we find 25 sources showing flux variability larger than a factor of 10, of which 17 show some evidence for (or are at least consistent with) exhibiting bi-modal flux distributions, as would be expected for sources undergoing propeller transitions. These sources are excellent candidates for continued monitoring programs to further test for this behaviour. There are 3 sources in our final sample with fluxes similar to NGC 5907 ULX1, currently the faintest known PULX, which would also be good targets for deeper observations with current facilities to search for pulsations. For the rest of the PULX candidates identified here, the next generation of X-ray telescopes (such as Athena) may be required to determine their nature owing to their lower peak fluxes., Comment: 19 pages, 11 figures. Accepted for publication in MNRAS

Published
2020

15. The unusual broad-band X-ray spectral variability of NGC 1313 X-1 seen with $XMM–Newton$, $Chandra$, and $Nu$STAR

Author

Dom Walton, Hannah P. Earnshaw, Murray Brightman, Fiona A. Harrison, R. Sathyaprakash, Timothy P.L. Roberts, A. C. Fabian, Lian Tao, Matthew J. Middleton, Didier Barret, D. Stern, P. Kosec, Felix Fürst, Ciro Pinto, Claude R. Canizares, Erin Kara, William Alston, N. A. Webb, Roberto Soria, Matteo Bachetti, M. Heida, Michael A. Nowak, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, X-rays: binaries, Accretion disc, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Black-body radiation, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Advection, X-ray, Broad band, Astronomy and Astrophysics, X-rays: individual: NGC 1313 X-1, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), Neutron star, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We present results from the major coordinated X-ray observing program on the ULX NGC 1313 X-1 performed in 2017, combining $XMM$-$Newton$, $Chandra$ and $NuSTAR$, focusing on the evolution of the broadband ($\sim$0.3-30.0 keV) continuum emission. Clear and unusual spectral variability is observed, but this is markedly suppressed above $\sim$10-15 keV, qualitatively similar to the ULX Holmberg IX X-1. We model the multi-epoch data with two-component accretion disc models designed to approximate super-Eddington accretion, allowing for both a black hole and a neutron star accretor. With regards to the hotter disc component, the data trace out two distinct tracks in the luminosity-temperature plane, with larger emitting radii and lower temperatures seen at higher observed fluxes. Despite this apparent anti-correlation, each of these tracks individually shows a positive luminosity-temperature relation. Both are broadly consistent with $L\propto{T}^{4}$, as expected for blackbody emission with a constant area, and also with $L\propto{T}^{2}$, as may be expected for an advection-dominated disc around a black hole. We consider a variety of possibilities for this unusual behaviour. Scenarios in which the innermost flow is suddenly blocked from view by outer regions of the super-Eddington disc/wind can explain the luminosity-temperature behaviour, but are difficult to reconcile with the lack of strong variability at higher energies, assuming this emission arises from the most compact regions. Instead, we may be seeing evidence for further radial stratification of the accretion flow than is included in the simple models considered, with a combination of winds and advection resulting in the suppressed high-energy variability., Comment: 18 pages, 7 figures, accepted for publication in MNRAS

Published
2020
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16. NuSTAR observations of Mrk 766: distinguishing reflection from absorption

Author

David R. Ballantyne, Michael Parker, Andrew C. Fabian, Fiona A. Harrison, Ciro Pinto, Douglas J. K. Buisson, Finn Erland Christensen, Daniel Stern, S. E. Boggs, Erin Kara, C. J. Hailey, Duncan Farrah, W. W. Zhang, W. W. Craig, R. V. Vasudevan, Claudio Ricci, Anne M. Lohfink, Dom Walton, Parker, Michael [0000-0002-8466-7317], Pinto, Ciro [0000-0003-2532-7379], Fabian, Andrew [0000-0002-9378-4072], Walton, Dominic [0000-0001-5819-3552], and Apollo - University of Cambridge Repository

Subjects
Accretion, Seyfert [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, individual: Mrk 766 [alaxies], black hole physics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 7. Clean energy, 01 natural sciences, Spectral line, law.invention, law, K band, Ionization, 0103 physical sciences, galaxies: individual: Mrk 766, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Bolometer, Astronomy and Astrophysics, Black hole physics, Astrophysics - Astrophysics of Galaxies, galaxies: Seyfert, Galaxy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), accretion, accretion discs, Astrophysics - High Energy Astrophysical Phenomena, Hybrid model, Accretion discs
Abstract

We present two new NuSTAR observations of the narrow line Seyfert 1 (NLS1) galaxy Mrk 766 and give constraints on the two scenarios previously proposed to explain its spectrum and that of other NLS1s: relativistic reflection and partial covering. The NuSTAR spectra show a strong hard (>15 keV) X-ray excess, while simultaneous soft X-ray coverage of one of the observations provided by XMM-Newton constrains the ionised absorption in the source. The pure reflection model requires a black hole of high spin ($a>0.92$) viewed at a moderate inclination ($i=46^{+1}_{-4}$ degrees). The pure partial covering model requires extreme parameters: the cut-off of the primary continuum is very low ($22^{+7}_{-5}$ keV) in one observation and the intrinsic X-ray emission must provide a large fraction (75%) of the bolometric luminosity. Allowing a hybrid model with both partial covering and reflection provides more reasonable absorption parameters and relaxes the constraints on reflection parameters. The fractional variability reduces around the iron K band and at high energies including the Compton hump, suggesting that the reflected emission is less variable than the continuum., 14 pages, 10 figures, MNRAS accepted

Published
2018
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17. Lense-Thirring precession in ULXs as a possible means to constrain the neutron star equation of state

Author

Adam Ingram, Wynn C. G. Ho, Ciro Pinto, Matteo Bachetti, Thomas Dauser, Murray Brightman, Timothy P.L. Roberts, Matthew J. Middleton, A. C. Fabian, Felix Fuerst, Dom Walton, N. Gehrels, P. C. Fragile, Y-F. Jiang, Pinto, Ciro [0000-0003-2532-7379], Walton, Dominic [0000-0001-5819-3552], Fabian, Andrew [0000-0002-9378-4072], Apollo - University of Cambridge Repository, High Energy Astrophys. & Astropart. Phys (API, FNWI), ITA, USA, GBR, DEU, and ESP

Subjects
Equation of state, Astrophysics::High Energy Astrophysical Phenomena, black hole physics, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, symbols.namesake, stars: neutron, X-rays: binaries, Pulsar, 0103 physical sciences, Radiative transfer, 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysics, Moment of inertia, Accretion (astrophysics), Neutron star, Space and Planetary Science, Eddington luminosity, symbols, accretion, accretion discs, Lense–Thirring precession, Astrophysics - High Energy Astrophysical Phenomena
Abstract

The presence of neutron stars in at least three ultraluminous X-ray sources is now firmly established and offers an unambiguous view of super-critical accretion. All three systems show long-timescale periods (60-80 days) in the X-rays and/or optical, two of which are known to be super-orbital in nature. Should the flow be classically super critical, i.e. the Eddington limit is reached locally in the disc (implying surface dipole fields that are sub-magnetar in strength), then the large scale-height flow can precess through the Lense-Thirring effect which could provide an explanation for the observed super-orbital periods. By connecting the details of the Lense-Thirring effect with the observed pulsar spin period, we are able to infer the moment-of-inertia and therefore equation-of-state of the neutron star without relying on the inclination of, or distance to the system. We apply our technique to the case of NGC 7793 P13 and demonstrate that stronger magnetic fields imply stiffer equations of state. We discuss the caveats and uncertainties, many of which can be addressed through forthcoming radiative magnetohydrodynamic (RMHD) simulations and their connection to observation., 14 pages, 9 figures, accepted to MNRAS

Published
2018
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18. Disentangling the complex broad-band X-ray spectrum of IRAS 13197−1627 with NuSTAR, XMM–Newton and Suzaku

Author

D. Stern, Fiona A. Harrison, A. C. Fabian, Giorgio Matt, Murray Brightman, Anne M. Lohfink, Guido Risaliti, Michael Parker, Dom Walton, Felix Fürst, Giovanni Miniutti, Walton, D. J., Brightman, M., Risaliti, G., Fabian, A. C., Fürst, F., Harrison, F. A., Lohfink, A., Matt, G., Miniutti, G., Parker, M. L., and Stern, D.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, X-ray, FOS: Physical sciences, Astronomy, Broad band, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Rotating black hole, Space and Planetary Science, Homogeneous, Astrophysics of Galaxies (astro-ph.GA), Reprocessor, Ionization, 0103 physical sciences, Outflow, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We present results from a coordinated $XMM$-$Newton$+$NuSTAR$ observation of the type 1.8 Seyfert galaxy IRAS 13197-1627. This is a highly complex source, with strong contributions from relativistic reflection from the inner accretion disk, neutral absorption and further reprocessing by more distant material, and ionised absorption from an outflow. We undertake a detailed spectral analysis combining the broadband coverage provided by $XMM$-$Newton$+$NuSTAR$ with a multi-epoch approach incorporating archival observations performed by $XMM$-$Newton$ and $Suzaku$. Our focus is on characterising the reflection from the inner accretion disk, which previous works have suggested may dominate the AGN emission, and constraining the black hole spin. Using lamppost disk reflection models, we find that the results for the inner disk are largely insensitive to assumptions regarding the geometry of the distant reprocessor and the precise form of the illuminating X-ray continuum. However, these results do depend on the treatment of the iron abundance of the distant absorber/reprocessor. The multi-epoch data favour a scenario in which the AGN is chemically homogeneous, and we find that a rapidly rotating black hole is preferred, with $a^* \geq 0.7$, but a slowly-rotating black hole is not strongly excluded. In addition to the results for the inner disk, we also find that both the neutral and ionised absorbers vary from epoch to epoch, implying that both have some degree of inhomogeneity in their structure., 15 pages, 7 figures, accepted for publication in MNRAS

Published
2017
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19. Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum

Author

Andrew J. King, K. G. Teems, Gabriele Ponti, J. S. Schimoia, Calen B. Henderson, Michael S. Brotherton, S. Paltani, Nahum Arav, Alessandro Siviero, Radosław Poleski, P. Lira, Sang Chul Kim, Thomas W.-S. Holoien, Wei Zhu, A. de Lorenzo-Cáceres, M. C. Bottorff, Dirk Grupe, Gabriela Canalizo, M. Eracleous, S. G. Sergeev, F. MacInnis, Massimo Cappi, M. Dietrich, Alis J. Deason, Haojing Yan, Giorgio Matt, Ciro Pinto, Michael T. Carini, Minjin Kim, Brandon C. Kelly, I. M. McHardy, Scott M. Adams, L. Gonzalez, J. J. Jensen, Julia M. Comerford, Yair Krongold, Tim Waters, B. Scott, C. S. Turner, G. A. Borman, R. McGurk, Nicolas Tejos, J. R. Parks, K. Flatland, Michael D. Joner, Kirk T. Korista, L. Di Gesu, Emma Gardner, Jon C. Mauerhan, Jessie C. Runnoe, Douglas C. Leonard, Kelsey I. Clubb, M. H. Siegel, C. A. Johnson, D. A. Starkey, H. Yuk, M. A. Malkan, Justin Ely, Ying Zu, Aaron J. Barth, Cassandra Lochhaas, Patrick L. Kelly, E. Holmbeck, Hyun-Il Sung, Patrick B. Hall, C. Montuori, Christopher S. Kochanek, Bradley M. Peterson, Tommaso Treu, Missagh Mehdipour, Marie Wingyee Lau, A. Skielboe, Catherine J. Grier, J. A. Kennea, Thomas G. Beatty, R. W. Pogge, J. van Saders, A. Bigley, S. Hicks, Catia Silva, H. W. Rix, Vardha N. Bennert, D. M. Crenshaw, E. Dalla Bontà, Miao Li, A. A. Breeveld, Dom Walton, D. N. Okhmat, Elisa Costantini, P. Ochner, Y. Weiss, M. L. Nguyen, Ryan Norris, Susanna Bisogni, Ehud Behar, Jacobo Ebrero, Garrett Somers, Phil Uttley, S. Rafter, Kelly D. Denney, K. Schnülle, Carolin Villforth, Keith Horne, Smita Mathur, G. V. Simonian, R. Boissay-Malaquin, Gary J. Ferland, J. S. Brown, Jelle Kaastra, Ana M. Mosquera, Stefano Bianchi, Misty C. Bentz, A. Pancoast, Alessandro Pizzella, WeiKang Zheng, N. Gehrels, Daniel J. Stevens, M. Dehghanian, Kevin V. Croxall, Isaac Shivvers, A. Gupta, Chris Done, J. E. Brown, B. De Marco, Gerard A. Kriss, Steve Croft, S. V. Nazarov, J. A. Nousek, Jae-Ok Lee, P. Arévalo, G. De Rosa, Michael Fausnaugh, Rick Edelson, Phil Evans, Lorenzo Morelli, S. Geier, Enrico Maria Corsini, M. R. Goad, V. Gorjian, W. N. Brandt, Elinor L. Gates, Shai Kaspi, D. A. Saylor, Jong-Hak Woo, Edward M. Cackett, Liuyi Pei, T. Hutchison, Jamie Tayar, E. R. Manne-Nicholas, Laura Vican, Daniel Proga, Steven Villanueva, D. Mudd, J.-U. Pott, F. Müller-Sánchez, Alexei V. Filippenko, Hagai Netzer, S. A. Klimanov, B. J. Shappee, J. M. Gelbord, Marianne Vestergaard, M. Spencer, Zhiyuan Ma, Carl T. Coker, S. Y. Kim, Myungshin Im, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, High Energy Astrophys. & Astropart. Phys (API, FNWI), Kriss, G. A., De Rosa, G., Ely, J., Peterson, B. M., Kaastra, J., Mehdipour, M., Ferland, G. J., Dehghanian, M., Mathur, S., Edelson, R., Korista, K. T., Arav, N., Barth, A. J., Bentz, M. C., Brandt, W. N., Crenshaw, D. M., Bontà, E. Dalla, Denney, K. D., Done, C., Eracleous, M., Fausnaugh, M. M., Gardner, E., Goad, M. R., Grier, C. J., Horne, Keith, Kochanek, C. S., Mchardy, I. M., Netzer, H., Pancoast, A., Pei, L., Pogge, R. W., Proga, D., Silva, C., Tejos, N., Vestergaard, M., Adams, S. M., Anderson, M. D., Arévalo, P., Beatty, T G., Behar, E., Bennert, V. N., Bianchi, S., Bigley, A., Bisogni, S., Boissay-Malaquin, R., Borman, G. A., Bottorff, M. C., Breeveld, A. A., Brotherton, M., Brown, J. E., Brown, J. S., Cackett, E. M., Canalizo, G., Cappi, M., Carini, M. T., Clubb, K. I., Comerford, J. M., Coker, C. T., Corsini, E. M., Costantini, E., Croft, S., Croxall, K. V., Deason, A. J., De Lorenzo-Cáceres, A., De Marco, B., Dietrich, M., Di Gesu, L., Ebrero, J., Evans, P. A., Filippenko, A. V., Flatland, K., Gates, E. L., Gehrels, N., Geier, S., Gelbord, J. M., Gonzalez, L., Gorjian, V., Grupe, D., Gupta, A., Hall, P. B., Henderson, C. B., Hicks, S., Holmbeck, E., Holoien, T. W. -S., Hutchison, T. A., Im, M., Jensen, J. J., Johnson, C. A., Joner, M. D., Kaspi, S., Kelly, B. C., Kelly, P. L., Kennea, J. A., Kim, M., Kim, S. C., Kim, S. Y., King, A., Klimanov, S. A., Krongold, Y., Lau, M. W., Lee, J. C., Leonard, D. C., Li, Miao, Lira, P., Lochhaas, C., Ma, Zhiyuan, Macinnis, F., Malkan, M. A., Manne-Nicholas, E. R., Matt, G., Mauerhan, J. C., Mcgurk, R., Montuori, C., Morelli, L., Mosquera, A., Mudd, D., Müller-Sánchez, F., Nazarov, S. V., Norris, R. P., Nousek, J. A., Nguyen, M. L., Ochner, P., Okhmat, D. N., Paltani, S., Parks, J. R., Pinto, C., Pizzella, A., Poleski, R., Ponti, G., Pott, J. -U., Rafter, S. E., Rix, H. -W., Runnoe, J., Saylor, D. A., Schimoia, J. S., Schnülle, K., Scott, B., Sergeev, S. G., Shappee, B. J., Shivvers, I., Siegel, M., Simonian, G. V., Siviero, A., Skielboe, A., Somers, G., Spencer, M., Starkey, D., Stevens, D. J., Sung, H. -I., Tayar, J., Teems, K. G., Treu, T., Turner, C. S., Uttley, P., Van Saders, J ., Vican, L., Villforth, C., Villanueva Jr., S., Walton, D. J., Waters, T., Weiss, Y., Woo, J. -H., Yan, H., Yuk, H., Zheng, W., Zhu, W., Zu, Y., and USA

Subjects
Seyfert [Galaxies], galaxies: active, galaxies: individual (NGC 5548), galaxies: nuclei, galaxies: Seyfert, 010504 meteorology & atmospheric sciences, Absorption spectroscopy, active [Galaxies], individual (NGC 5548) [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Continuum (design consultancy), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, Luminosity, 0103 physical sciences, QB Astronomy, Emission spectrum, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, QC, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, QB, Physics, Astronomy and Astrophysics, DAS, Astrophysics - Astrophysics of Galaxies, Galaxy, QC Physics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), nuclei [Galaxies], Reverberation mapping
Abstract

We model the ultraviolet spectra of the Seyfert 1 galaxy NGC~5548 obtained with the Hubble Space Telescope during the 6-month reverberation-mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum variations for the deblended and absorption-corrected individual broad emission lines, the velocity-dependent profiles of Ly$\alpha$ and C IV, and the narrow and broad intrinsic absorption features. We find that the time lags for the corrected emission lines are comparable to those for the original data. The velocity-binned lag profiles of Ly$\alpha$ and C IV have a double-peaked structure indicative of a truncated Keplerian disk. The narrow absorption lines show delayed response to continuum variations corresponding to recombination in gas with a density of $\sim 10^5~\rm cm^{-3}$. The high-ionization narrow absorption lines decorrelate from continuum variations during the same period as the broad emission lines. Analyzing the response of these absorption lines during this period shows that the ionizing flux is diminished in strength relative to the far-ultraviolet continuum. The broad absorption lines associated with the X-ray obscurer decrease in strength during this same time interval. The appearance of X-ray obscuration in $\sim\,2012$ corresponds with an increase in the luminosity of NGC 5548 following an extended low state. We suggest that the obscurer is a disk wind triggered by the brightening of NGC 5548 following the decrease in size of the broad-line region during the preceding low-luminosity state., Comment: 50 pages, 30 figures, uses aastex62.cls. Accepted for publication in ApJ, 07/06/2019. High-level products page in MAST will go live after 7/15/2019. Replaced Figure 4 on 7/12/2019 to be more red/green color-blind friendly

Published
2019
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20. A low-flux state in IRAS 00521−7054 seen with NuSTAR and XMM–Newton: relativistic reflection and an ultrafast outflow

Author

Fiona A. Harrison, A. C. Fabian, Daniel Stern, Thomas Dauser, Claudio Ricci, Guido Risaliti, Dom Walton, Luigi C. Gallo, Emanuele Nardini, Javier A. García, and Mark Reynolds

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Supermassive black hole, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Flux, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galaxy, Space and Planetary Science, Ionization, 0103 physical sciences, Reflection (physics), Astrophysics::Solar and Stellar Astrophysics, Outflow, Astrophysics - High Energy Astrophysical Phenomena, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract

We present results from a deep, coordinated $XMM$-$Newton$+$NuSTAR$ observation of the Seyfert 2 galaxy IRAS 00521-7054. The $NuSTAR$ data provide the first detection of this source in high-energy X-rays ($E > 10$ keV), and the broadband data show this to be a highly complex source which exhibits relativistic reflection from the inner accretion disc, further reprocessing by more distant material, neutral absorption, and evidence for ionised absorption in an extreme, ultrafast outflow ($v_{\rm{out}} \sim 0.4c$). Based on lamppost disc reflection models, we find evidence that the central supermassive black hole is rapidly rotating ($a > 0.77$), consistent with previous estimates from the profile of the relativistic iron line, and that the accretion disc is viewed at a fairly high inclination ($i \sim 59^{\circ}$). Based on extensive simulations, we find the ultrafast outflow is detected at $\sim$4$��$ significance (or greater). We also estimate that the extreme outflow should be sufficient to power galaxy-scale feedback, and may even dominate the energetics of the total output from the system., 12 pages, 8 figures; accepted for publication in MNRAS

Published
2019

21. XRB continuum fitting with sensitive high-energy X-ray detectors

Author

John A. Tomsick, Felix Fürst, Dom Walton, Andrew C. Fabian, K. K. Madsen, Michael Parker, and Douglas J. K. Buisson

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Line fitting, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, X-ray detector, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Parameter space, 01 natural sciences, Accretion (astrophysics), Spectral line, law.invention, Telescope, Space and Planetary Science, law, 0103 physical sciences, Relativistic quantum chemistry, Spectroscopy, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics
Abstract

The launch of the Nuclear Spectroscopic Telescope Array (NuSTAR) heralded a new era of sensitive high energy X-ray spectroscopy for X-ray binaries (XRBs). In this paper we show how multiple physical parameters can be measured from the accretion disk spectrum when the high-energy side of the disk spectrum can be measured precisely using NuSTAR. This immediately makes two exciting developments possible. If the mass and distance of the source are known, the continuum fitting method can be used to calculate the spin and inner disk inclination independently of the iron line fitting method. If the mass and distance are unknown, the two methods can be combined to constrain these values to a narrow region of parameter space. In this paper we perform extensive simulations to establish the reliability of these techniques. We find that with high quality spectra, spin and inclination can indeed be simultaneously measured using the disk spectrum. These measurements are much more precise at higher spin values, where the relativistic effects are stronger. The inclusion of a soft X-ray snapshot observation alongside the NuSTAR data significantly improves the reliability, particularly for lower temperature disks, as it gives a greatly improved measurement of the disk peak. High signal to noise data are not necessary for this, as measuring the peak temperature is relatively easy. We discuss the impact of systematic effects on this technique, and the implications of our results such as robust measurements of accretion disk warps and XRB mass surveys., 11 pages, 9 figures, accepted for publication in MNRAS

Published
2019

22. On the magnetic field in M51 ULX-8

Author

Fabio Pintore, Matthew J. Middleton, Dom Walton, Matteo Bachetti, Andrew C. Fabian, Felix Fürst, Murray Brightman, ITA, USA, GBR, and ESP

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Field (physics), 010308 nuclear & particles physics, Scattering, Astrophysics::High Energy Astrophysical Phenomena, Cyclotron resonance, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Magnetic field, Dipole, Neutron star, Space and Planetary Science, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Multipole expansion, 010303 astronomy & astrophysics, Magnetic dipole, Astrophysics::Galaxy Astrophysics
Abstract

The reported discovery of a cyclotron resonance scattering feature (CRSF) in the spectrum of M51 ULX-8 may provide an important clue as to the nature of the magnetic field in those ultraluminous X-ray sources hosting neutron stars. In this paper we present the covariance (linearly correlated variability) spectrum of M51 ULX-8 on long (> 2000s) timescales. This allows us to unambiguously decompose the spectrum which requires multiple components in order to explain the broad-band emission. Having a clearer picture of the spectral decomposition leads to various tests for the dipole field strength of the neutron star which can be extended to other ULXs when certain criteria are met. In the case of M51 ULX-8, we rule out a very strong (~10^15 G) dipole solution with either a sub- or super-critical disc. Instead, our tests indicate an upper limit on the dipole field of ~10^12 G, and a classical super-critical inflow, similar to that inferred in other ULXs found to harbour neutron stars, although we do not rule out the presence of an additional, strong (~10^15 G) multipole field falling off steeply with distance from the neutron star., 9 pages, 4 figures, accepted to MNRAS, updated following corrections

Published
2019
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23. A new, clean catalogue of extragalactic non-nuclear X-ray sources in nearby galaxies

Author

Silvia Mateos, Matthew J. Middleton, Hannah P. Earnshaw, Timothy P.L. Roberts, Dom Walton, Universidad de Cantabria, Science and Technology Facilities Council (UK), National Aeronautics and Space Administration (US), Ministerio de Economía y Competitividad (España), and European Commission

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, X-rays: general, 01 natural sciences, X-rays: binaries, general [X-rays], 0103 physical sciences, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, education.field_of_study, 010308 nuclear & particles physics, Hardness ratio, Astronomy and Astrophysics, Black hole physics, Catalogues, Galaxy, Black hole, Future study, Space and Planetary Science, binaries [X-rays], Sensitivity limit, Astrophysics - High Energy Astrophysical Phenomena, Data release
Abstract

We have created a new, clean catalogue of extragalactic non-nuclear X-ray sources by correlating the 3XMM-DR4 data release of the XMM-Newton Serendipitous Source Catalogue with the Third Reference Catalogue of Bright Galaxies and the Catalogue of Neighbouring Galaxies, using an improved version of the method presented in Walton et al. (2011). Our catalogue contains 1,314 sources, of which 384 are candidate ultraluminous X-ray sources (ULXs). The resulting catalogue improves upon previous catalogues in its handling of spurious detections by taking into account XMM-Newton quality flags. We estimate the contamination of ULXs by background sources to be 24 per cent. We define a 'complete' subsample as those ULXs in galaxies for which the sensitivity limit is below $10^{39}$ erg/s and use it to examine the hardness ratio properties between ULX and non-ULX sources, and ULXs in different classes of host galaxy. We find that ULXs have a similar hardness ratio distribution to lower-luminosity sources, consistent with previous studies. We also find that ULXs in spiral and elliptical host galaxies have similar distributions to each other independent of host galaxy morphology, however our results do support previous indications that the population of ULXs is more luminous in star-forming host galaxies than in non-star-forming galaxies. Our catalogue contains further interesting subpopulations for future study, including Eddington Threshold sources and highly variable ULXs. We also examine the highest-luminosity (L$_X$ > $5 \times 10^{40}$ erg/s) ULXs in our catalogue in search of intermediate-mass black hole candidates, and find nine new possible candidates., 20 pages, 14 figures, 7 tables. Accepted for publication by MNRAS

Published
2019

24. Discovery of a 2.8 s Pulsar in a 2 Day Orbit High-mass X-Ray Binary Powering the Ultraluminous X-Ray Source ULX-7 in M51

Author

Alessandro Papitto, Fiona A. Harrison, G. L. Israel, Ruben Salvaterra, A. De Luca, Simone Dall'Osso, Piergiorgio Casella, G. A. Rodriguez Castillo, Luca Zampieri, R. Turolla, Luigi Stella, Federico Bernardini, Andrea Belfiore, Anna Wolter, Andrea Tiengo, Timothy P.L. Roberts, H. P. Earnshaw, Daniele D'Agostino, Frank Haberl, Matteo Bachetti, Murray Brightman, F. Pintore, M. Marelli, Carmine Pinto, Felix Fürst, Michela Mapelli, Paolo Esposito, Dom Walton, and Matthew Middleton

Subjects
Ultraluminous X-ray source, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, X-ray binary, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, x-rays, 01 natural sciences, M51 ULX-7, Luminosity, Pulsar, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Spiral galaxy, accretion disks, Astronomy and Astrophysics, astronomy, Neutron star, Amplitude, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, Magnetic dipole
Abstract

We discovered 2.8 s pulsations in the X-ray emission of the ultraluminous X-ray source (ULX) M51 ULX-7 within the UNSEeN project, which was designed to hunt for new pulsating ULXs (PULXs) with XMM-Newton. The pulse shape is sinusoidal and large variations of its amplitude were observed even within single exposures (pulsed fraction from less than 5% to 20%). M51 ULX-7 is a variable source, generally observed at an X-ray luminosity between $10^{39}$ and $10^{40}$ erg s$^{-1}$, located in the outskirts of the spiral galaxy M51a at a distance of 8.6 Mpc. According to our analysis, the X-ray pulsar orbits in a 2-d binary with a projected semi-major axis $a_\mathrm{X} \sin i \simeq$ 28 lt-s. For a neutron star (NS) of 1.4 $M_{\odot}$, this implies a lower limit on the companion mass of 8 $M_{\odot}$, placing the system hosting M51 ULX-7 in the high-mass X-ray binary class. The barycentric pulse period decreased by $\simeq$0.4 ms in the 31 d spanned by our May -- June 2018 observations, corresponding to a spin-up rate $\dot{P} \simeq -1.5\times10^{-10}\text{s s}^{-1}$. In an archival 2005 XMM-Newton exposure, we measured a spin period of $\sim$3.3 s, indicating a secular spin-up of $\dot{P}_{\mathrm{sec}}\simeq -10^{-9}\text{ s s}^{-1}$, a value in the range of other known PULXs. Our findings suggest that the system consists of an OB giant and a moderately magnetic (dipole field component in the range $10^{12}$ G $\lesssim B_{\mathrm{dip}}\lesssim 10^{13}$G) accreting NS with weakly beamed emission ($1/12\lesssim b\lesssim1/4$)., Comment: Accepted for publication in The Astrophysical Journal

Published
2020
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25. Constraining the geometry of AGN outflows with reflection spectroscopy

Author

Douglas J. K. Buisson, Luigi C. Gallo, Dom Walton, G. A. Matzeu, Jiachen Jiang, Erin Kara, and Michael Parker

Subjects
Physics, Systematic error, High Energy Astrophysical Phenomena (astro-ph.HE), Active galactic nucleus, Reflection spectroscopy, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Economic shortage, Geometry, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Accretion (astrophysics), Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Outflow, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We collate active galactic nuclei (AGN) with reported detections of both relativistic reflection and ultra-fast outflows. By comparing the inclination of the inner disc from reflection with the line-of-sight velocity of the outflow, we show that it is possible to meaningfully constrain the geometry of the absorbing material. We find a clear relation between the velocity and inclination, and demonstrate that it can potentially be explained either by simple wind geometries or by absorption from the disc surface. Due to systematic errors and a shortage of high- quality simultaneous measurements our conclusions are tentative, but this study represents a proof-of-concept that has great potential., 5 pages, 3 figures, accepted to MNRAS letters

Published
2018

26. Heavy X-ray obscuration in the most luminous galaxies discovered by WISE

Author

Chien-Ting J. Chen, W. N. Brandt, Murray Brightman, Chao-Wei Tsai, Roberto J. Assef, D. Stern, Ryan C. Hickox, Dom Walton, Andrea Comastri, Fabio Vito, J. Wu, Peter Eisenhardt, George B. Lansbury, and Gordon P. Garmire

Subjects
Physics, Luminous infrared galaxy, Supermassive black hole, Active galactic nucleus, obscured quasars, 010308 nuclear & particles physics, Hardness ratio, X-ray, FOS: Physical sciences, galaxy evolution, Astronomy and Astrophysics, Active Galactic Nuclei, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Galaxy formation and evolution, Spectral fitting, AGN, 010303 astronomy & astrophysics
Abstract

Hot Dust-Obscured Galaxies (Hot DOGs) are hyperluminous ($L_{\mathrm{8-1000\,��m}}>10^{13}\,\mathrm{L_\odot}$) infrared galaxies with extremely high (up to hundreds of K) dust temperatures. The sources powering both their extremely high luminosities and dust temperatures are thought to be deeply buried and rapidly accreting supermassive black holes (SMBHs). Hot DOGs could therefore represent a key evolutionary phase in which the SMBH growth peaks. X-ray observations can be used to study their obscuration levels and luminosities. In this work, we present the X-ray properties of the 20 most-luminous ($L_{\mathrm{bol}}\gtrsim10^{14}\, L_\odot$) known Hot DOGs at $z=2-4.6$. Five of them are covered by long-exposure ($10-70$ ks) Chandra and XMM-Newton observations, with three being X-ray detected, and we study their individual properties. One of these sources (W0116$-$0505) is a Compton-thick candidate, with column density $N_H=(1.0-1.5)\times10^{24}\,\mathrm{cm^{-2}}$ derived from X-ray spectral fitting. The remaining 15 Hot DOGs have been targeted by a Chandra snapshot (3.1 ks) survey. None of these 15 is individually detected; therefore we applied a stacking analysis to investigate their average emission. From hardness-ratio analysis, we constrained the average obscuring column density and intrinsic luminosity to be log$N_H\,\mathrm{[cm^{-2}]}>23.5$ and $L_X\gtrsim10^{44}\,\mathrm{erg\,cm^{-2}\,s^{-1}}$, which are consistent with results for individually detected sources. We also investigated the $L_X-L_{6��\mathrm{m}}$ and $L_X-L_{bol}$ relations, finding hints that Hot DOGs are typically X-ray weaker than expected, although larger samples of luminous obscured QSOs are needed to derive solid conclusions., MNRAS, accepted 2017 November 29 . Received 2017 November 29 ; in original form 2017 October 11. 15 pages, 6 figures

Published
2018

27. NuSTAR spectral analysis of two bright Seyfert 1 galaxies: MCG +8-11-11 and NGC 6814

Author

Mauro Dadina, Andrea Marinucci, Massimo Cappi, Giorgio Matt, A. de Rosa, Dom Walton, R. Middei, Laura Brenneman, Francesco Ursini, Enrico Piconcelli, Stefano Bianchi, A. Tortosa, P.-O. Petrucci, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Tortosa, A., Bianchi, S., Marinucci, A., Matt, G., Middei, R., Piconcelli, E., Brenneman, L. W., Cappi, M., Dadina, M., De Rosa, A., Petrucci, P. O., Ursini, F., Walton, D. J., Institut de Planétologie et d'Astrophysique de Grenoble ( IPAG ), Observatoire des Sciences de l'Univers de Grenoble ( OSUG ), and Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
Active galactic nucleus, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], Astrophysics::High Energy Astrophysical Phenomena, galaxies: individual: MCG +8-11-11, galaxies: active, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, 0103 physical sciences, Spectral analysis, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, galaxies: individual: NGC 6814, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysics, Plasma, Galaxy, galaxies: Seyfert, X-rays: galaxies, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We report on the NuSTAR observations of two bright Seyfert 1 galaxies, namely MCG +8-11-11 (100 ks) and NGC 6814 (150 ks). The main goal of these observations was to investigate the Comptonization mechanisms acting in the innermost regions of AGN which are believed to be responsible for the UV/X-ray emission. The spectroscopic analysis of the NuSTAR spectra of these two sources revealed that although they had different properties overall (black hole masses, luminosity and Eddington ratios) they had very similar coronal properties. Both presented a power law spectrum with a high-energy cutoff at $\sim 150-200$ keV, a relativistically broadened Fe K$\alpha$ line and the associated disk reflection component, plus a narrow iron line likely emitted in Compton thin and distant matter. The intrinsic continuum was well described by Comptonization models that show for MCG +8-11-11 a temperature of the coronal plasma of kT$_{\rm e} \sim$ 60 keV and an extrapolated optical depth $\tau$=1.8; for NGC 6814 the coronal temperature was kT$_{\rm e} \sim$ 45 keV with an extrapolated optical depth of $\tau$=2.5. We compare and discuss these values to some most common Comptonization models which aim at explaining the energy production and stability of coronae in active galactic nuclei.

Published
2018
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28. A Potential Cyclotron Resonant Scattering Feature in the Ultraluminous X-Ray Source Pulsar NGC 300 ULX1 Seen by NuSTAR and XMM-Newton

Author

Dom Walton, J. A. Kennea, P. Kosec, Murray Brightman, Marianne Heida, J. Steiner, Ryan M. Lau, Ciro Pinto, Fiona A. Harrison, F. Fürst, Matthew J. Middleton, N. A. Webb, Matteo Bachetti, Didier Barret, Andrew C. Fabian, Brian W. Grefenstette, K. K. Madsen, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), ITA, USA, GBR, FRA, Institut de recherche en astrophysique et planétologie ( IRAP ), and Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
Ultraluminous X-ray source, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], Astrophysics::High Energy Astrophysical Phenomena, Cyclotron, Astrophysics, Electron, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, law.invention, stars: neutron, X-rays: binaries, Pulsar, law, 0103 physical sciences, 010306 general physics, Spectroscopy, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Line (formation), Physics, Scattering, Astronomy and Astrophysics, Neutron star, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], X-rays: individual
Abstract

International audience; Based on phase-resolved broadband spectroscopy using XMM-Newton and NuSTAR, we report on a potential cyclotron resonant scattering feature (CRSF) at E ∼ 13 keV in the pulsed spectrum of the recently discovered ultraluminous X-ray source (ULX) pulsar NGC 300 ULX1. If this interpretation is correct, the implied magnetic field of the central neutron star is B ∼ 1012 G (assuming scattering by electrons), similar to that estimated from the observed spin-up of the star, and also similar to known Galactic X-ray pulsars. We discuss the implications of this result for the connection between NGC 300 ULX1 and the other known ULX pulsars, particularly in light of the recent discovery of a likely proton cyclotron line in another ULX, M51 ULX-8.

Published
2018
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29. A new Ultraluminous X-ray source in the galaxy NGC 5907

Author

Fabio Pintore, Andrea Belfiore, A. De Luca, G. Rodriguez, Andrea Tiengo, M. Marelli, Luca Zampieri, G. Novara, G. L. Israel, Ruben Salvaterra, Dom Walton, Felix Fuerst, C. Salvaggio, Sandro Mereghetti, Michela Rigoselli, Anna Wolter, Elena Ambrosi, Pintore, F, Belfiore, A, Novara, G, Salvaterra, R, Marelli, M, De&nbsp, Luca, A, Rigoselli, M, Israel, G, Rodriguez, G, Mereghetti, S, Wolter, A, Walton, D, Fuerst, F, Ambrosi, E, Zampieri, L, Tiengo, A, Salvaggio, C, ITA, GBR, and ESP

Subjects
accretion, accretion discs, X-rays: binaries, X-rays: galaxies, X-rays: individual: NGC 5907 ULX-2, Ultraluminous X-ray source, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Luminosity, FIS/05 - ASTRONOMIA E ASTROFISICA, symbols.namesake, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Solar mass, Accretion (meteorology), Astronomy and Astrophysics, Galaxy, Black hole, Neutron star, Space and Planetary Science, Eddington luminosity, symbols, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We report on the serendipitous discovery of a new transient in NGC 5907, at a peak luminosity of 6.4x10^{39} erg/s. The source was undetected in previous 2012 Chandra observations with a 3 sigma upper limit on the luminosity of 1.5x10^{38} erg/s, implying a flux increase of a factor of >35. We analyzed three recent 60ks/50ks Chandra and 50ks XMM-Newton observations, as well as all the available Swift observations performed between August 2017/March 2018. Until the first half of October 2017, Swift observations do not show any emission from the source. The transient entered the ULX regime in less than two weeks and its outburst was still on-going at the end of February 2018. The 0.3-10 keV spectrum is consistent with a single multicolour blackbody disc (kT~1.5 keV). The source might be a ~30 solar mass black hole accreting at the Eddington limit. However, although we did not find evidence of pulsations, we cannot rule-out the possibility that this ULX hosts an accreting neutron star., Accepted on MNRAS, 5 pages, 2 figure, 1 table

Published
2018
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30. A tale of two periods: determination of the orbital ephemeris of the super-Eddington pulsar NGC 7793 P13

Author

V. Rana, Ciro Pinto, Peter Kretschmar, Fiona A. Harrison, A. C. Fabian, Frank Tramper, M. Heida, Murray Brightman, Felix Fürst, Didier Barret, N. A. Webb, Dom Walton, Matthew Middleton, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
TELESCOPE, Astrophysics::High Energy Astrophysical Phenomena, X-RAY SOURCES, Orbital resonance, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, Ephemeris, Computer Science::Digital Libraries, 01 natural sciences, neutron [stars], Pulsar, Accretion disc, individual: NGC 7793 P13 [pulsars], SPECTRAL-ANALYSIS, 0103 physical sciences, MAGNETIC NEUTRON-STARS, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ULTRALUMINOUS STATE, XMM-NEWTON, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), accretion, accretion disks, Science & Technology, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, radial velocities [techniques], Astronomy and Astrophysics, NGC 7793 P13, Orbital period, Physics::History of Physics, SIMULATIONS, Accretion (astrophysics), Space and Planetary Science, Physical Sciences, BLACK-HOLE, ACCRETION DISKS, System parameters, binaries [X-rays], Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We present a timing analysis of multiple XMM-Newton and NuSTAR observations of the ultra-luminous pulsar NGC 7793 P13 spread over its 65d variability period. We use the measured pulse periods to determine the orbital ephemeris, confirm a long orbital period with P_orb = 63.9 (+0.5,-0.6) d, and find an eccentricity of e, 10 pages, 6 figures, accepted for publication in A&A

Published
2018
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31. Magnetic field strength of a neutron-star-powered ultraluminous X-ray source

Author

Fiona A. Harrison, Andrew C. Fabian, Murray Brightman, Didier Barret, Dom Walton, D. Stern, Matthew J. Middleton, Marianne Heida, Felix Fürst, Matteo Bachetti, Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), ITA, USA, GBR, FRA, ESP, Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Centre d'étude spatiale des rayonnements ( CESR ), and Université Paul Sabatier - Toulouse 3 ( UPS ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
Ultraluminous X-ray source, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], Astrophysics::High Energy Astrophysical Phenomena, Cyclotron resonance, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, symbols.namesake, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Supermassive black hole, Scattering, Astronomy and Astrophysics, Accretion (astrophysics), Neutron star, Radiation pressure, Eddington luminosity, symbols, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Ultraluminous X-ray sources (ULXs) are bright X-ray sources in nearby galaxies not associated with the central supermassive black hole. Their luminosities imply they are powered by either an extreme accretion rate onto a compact stellar remnant, or an intermediate mass ($\sim100-10^5$ M$_{\odot}$) black hole. The recent detection of coherent pulsations coming from three bright ULXs demonstrates that some of these sources are powered by accretion onto a neutron star, implying accretion rates significantly in excess of the Eddington limit, a high degree of geometric beaming, or both. The physical challenges associated with the high implied accretion rates can be mitigated if the neutron star surface field is high - in the magnetar regime ($10^{14}$ G), since this suppresses the electron scattering cross section, reducing the radiation pressure that chokes off accretion for high luminosities. One of the few ways to determine surface magnetic fields is through the detection of cyclotron resonance scattering features (CRSFs) produced by the transition of charged particles between quantized Landau levels. To date, CRSFs have only been detected in Galactic accreting pulsars. Here we present the detection at 3.8-{\sigma} significance of a strong absorption line at a rest-frame energy of 4.5 keV in the Chandra spectrum of a ULX in M51. We find that this feature is likely to be a CRSF produced by the strong magnetic field of a neutron star. Assuming scattering off electrons, the magnetic field strength is implied to be $\sim10^{11}$ G, however the line is narrower than any electron CRSFs previously observed, and assuming thermal broadening, the implied temperature is significantly cooler than the accretion disk or column. The line shape is, however, consistent with a proton resonance scattering feature, implying that the neutron star has a magnetic field near the surface of B$\sim10^{15}$ G., Comment: Author version of the paper published in Nature Astronomy on 26 February 2018. See free-to-view published version here: http://rdcu.be/HQpR

Published
2018
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32. The 1.5 Ms Observing Campaign on IRAS 13224-3809: X-ray Spectral Analysis I

Author

Giovanni Miniutti, Thomas Dauser, Douglas J. K. Buisson, Chia-Ying Chiang, B. De Marco, Jon M. Miller, Erin Kara, Javier A. García, Jiachen Jiang, Luigi C. Gallo, Dan R. Wilkins, Fiona A. Harrison, Ciro Pinto, A. C. Fabian, William Alston, Edward M. Cackett, Michael Parker, Dom Walton, and Anne M. Lohfink

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Electron density, Absorption spectroscopy, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Light curve, 01 natural sciences, Galaxy, Spectral line, Gravitation, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Space and Planetary Science, Ionization, 0103 physical sciences, Outflow, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics
Abstract

We present a detailed spectral analysis of the recent 1.5\,Ms XMM-Newton observing campaign on the narrow line Seyfert 1 galaxy IRAS~13224$-$3809, taken simultaneously with 500\,ks of NuSTAR data. The X-ray lightcurve shows three flux peaks, registering at about 100 times the minimum flux seen during the campaign, and rapid variability with a time scale of kiloseconds. The spectra are well fit with a primary powerlaw continuum, two relativistic-blurred reflection components from the inner accretion disk with very high iron abundance, and a simple blackbody-shaped model for the remaining soft excess. The spectral variability is dominated by the power law continuum from a corona region within a few gravitational radii from the black hole. Additionally, blueshifted Ne \textsc{x}, Mg \textsc{xii}, Si \textsc{xiv} and S \textsc{xvi} absorption lines are identified in the stacked low-flux spectrum, confirming the presence of a highly ionized outflow with velocity up to $v= 0.267$ and $0.225$\,c. We fit the absorption features with \texttt{xstar} models and find a relatively constant velocity outflow through the whole observation. Finally, we replace the \texttt{bbody} and supersolar abundance reflection models by fitting the soft excess successfully with the extended reflection model \texttt{relxillD}, which allows for higher densities than the standard \texttt{relxill} model. This returns a disk electron density $n_{\rm e}>10^{18.7}$\,cm$^{-3}$ and lowers the iron abundance from $Z_{\rm Fe}=24^{+3}_{-4}Z_\odot$ with $n_{\rm e}\equiv10^{15}$\,cm$^{-3}$ to $Z_{\rm Fe}=6.6^{+0.8}_{-2.1}Z_\odot$., 18 pages, 14 figures. Accepted by MNRAS

Published
2018
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33. Evidence for Pulsar-like Emission Components in the Broadband ULX Sample

Author

Matthew J. Middleton, Dom Walton, Daniel Stern, Murray Brightman, Felix Fürst, Fiona A. Harrison, Andrew C. Fabian, Didier Barret, Marianne Heida, Matteo Bachetti, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), ITA, USA, GBR, and FRA

Subjects
Spectral shape analysis, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], Astrophysics::High Energy Astrophysical Phenomena, Population, Magnetosphere, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, stars: neutron, X-rays: binaries, Pulsar, 0103 physical sciences, Broadband, Astrophysics::Solar and Stellar Astrophysics, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), education.field_of_study, Accretion (meteorology), 010308 nuclear & particles physics, Astronomy and Astrophysics, Neutron star, Space and Planetary Science, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], X-rays: individual
Abstract

We present broadband X-ray analyses of a sample of bright ultraluminous X-ray sources with the goal of investigating the spectral similarity of this population to the known ULX pulsars, M82 X-2, NGC7793 P13 and NGC5907 ULX. We perform a phase-resolved analysis of the broadband XMM-Newton+NuSTAR dataset of NGC5907 ULX, finding that the pulsed emission from the accretion column in this source exhibits a similar spectral shape to that seen in both M82 X-2 and NGC7793 P13, and that this is responsible for the excess emission observed at the highest energies when the spectra are fit with accretion disk models. We then demonstrate that similar 'hard' excesses are seen in all the ULXs in the broadband sample. Finally, for the ULXs where the nature of the accretor is currently unknown, we test whether the hard excesses are all consistent with being produced by an accretion column similar to those present in M82 X-2, NGC7793 P13 and NGC5907 ULX. Based on the average shape of the pulsed emission, we find that in all cases a similar accretion column can successfully reproduce the observed data, consistent with the hypothesis that this ULX sample may be dominated by neutron star accretors. Compared to the known pulsar ULXs, our spectral fits for the remaining ULXs suggest that the non-pulsed emission from the accretion flow beyond the magnetosphere makes a stronger relative contribution than the component associated with the accretion column. If these sources do also contain neutron star accretors, this may help to explain the lack of detected pulsations., 13 pages, 6 figures; accepted for publication in ApJ

Published
2018
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34. The Broadband Spectral Variability of Holmberg IX X-1

Author

D. Stern, Fiona A. Harrison, Dom Walton, A. C. Fabian, F. Fuerst, Didier Barret, Lian Tao, Matthew J. Middleton, Matteo Bachetti, A. F. Ptak, Jon M. Miller, V. Rana, Walton, Dominic [0000-0001-5819-3552], Fabian, Andrew [0000-0002-9378-4072], and Apollo - University of Cambridge Repository

Subjects
Astrophysics::High Energy Astrophysical Phenomena, black hole physics, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 7. Clean energy, 01 natural sciences, Spectral line, X-rays: binaries, 0103 physical sciences, Thermal, Black-body radiation, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Line-of-sight, Accretion (meteorology), Degree (graph theory), 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Outflow, Astrophysics - High Energy Astrophysical Phenomena, X-rays: individual (Holmberg IX X-1)
Abstract

We present results from four new broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 ($L_{\rm{X}} > 10^{40}$ erg/s), performed by $Suzaku$ and $NuSTAR$ in coordination. Combined with the archival data, we now have broadband observations of this remarkable source from six separate epochs. Two of these new observations probe lower fluxes than seen previously, allowing us to extend our knowledge of the broadband spectral variability exhibited. The spectra are well fit by two thermal blackbody components, which dominate the emission below 10 keV, as well as a steep ($\Gamma \sim 3.5$) powerlaw tail which dominates above $\sim$15 keV. Remarkably, while the 0.3-10.0 keV flux varies by a factor of $\sim$3 between all these epochs, the 15-40 keV flux varies by only $\sim$20%. Although the spectral variability is strongest in the $\sim$1-10 keV band, both of the thermal components are required to vary when all epochs are considered. We also re-visit the search for iron absorption features, leveraging the high-energy $NuSTAR$ data to improve our sensitivity to extreme velocity outflows in light of the ultra-fast outflow recently detected in NGC 1313 X-1. Iron absorption from a similar outflow along our line of sight can be ruled out in this case. We discuss these results in the context of super-Eddington accretion models that invoke a funnel-like geometry for the inner flow, and propose a scenario in which we have an almost face-on view of a funnel that expands to larger radii with increasing flux, resulting in an increasing degree of geometrical collimation for the emission from intermediate temperature regions., Comment: 11 pages, 6 Figures, accepted for publication in ApJ

Published
2017

35. Living on a Flare: Relativistic Reflection in V404 Cyg Observed by NuSTAR during Its Summer 2015 Outburst

Author

Matthew J. Middleton, V. Rana, F. Fuerst, Thomas Dauser, Fiona A. Harrison, David L. Meier, A. C. Fabian, Javier A. García, A. L. King, K. K. Madsen, Dom Walton, Matteo Bachetti, K. Forster, D. Stern, Poshak Gandhi, Jon M. Miller, John A. Tomsick, Lorenzo Natalucci, Brian W. Grefenstette, Farid Rahoui, Murray Brightman, Kunal Mooley, Walton, Dominic [0000-0001-5819-3552], Fabian, Andrew [0000-0002-9378-4072], and Apollo - University of Cambridge Repository

Subjects
Astrophysics::High Energy Astrophysical Phenomena, black hole physics, Flux, FOS: Physical sciences, Astrophysics, 01 natural sciences, law.invention, Gravitation, X-rays: binaries, law, Primary (astronomy), 0103 physical sciences, X-rays: individual (V404 Cyg), Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Jet (fluid), Accretion (meteorology), 010308 nuclear & particles physics, Astronomy and Astrophysics, Black hole, 13. Climate action, Space and Planetary Science, Reflection (physics), Astrophysics - High Energy Astrophysical Phenomena, Flare
Abstract

We present first results from a series of $NuSTAR$ observations of the black hole X-ray binary V404 Cyg obtained during its summer 2015 outburst, primarily focusing on observations during the height of this outburst activity. The $NuSTAR$ data show extreme variability in both the flux and spectral properties of the source. This is partly driven by strong and variable line-of-sight absorption, similar to previous outbursts. The latter stages of this observation are dominated by strong flares, reaching luminosities close to Eddington. During these flares, the central source appears to be relatively unobscured and the data show clear evidence for a strong contribution from relativistic reflection, providing a means to probe the geometry of the innermost accretion flow. Based on the flare properties, analogy with other Galactic black hole binaries, and also the simultaneous onset of radio activity, we argue that this intense X-ray flaring is related to transient jet activity during which the ejected plasma is the primary source of illumination for the accretion disk. If this is the case, then our reflection modelling implies that these jets are launched in close proximity to the black hole (as close as a few gravitational radii), consistent with expectations for jet launching models that tap either the spin of the central black hole, or the very innermost accretion disk. Our analysis also allows us to place the first constraints on the black hole spin for this source, which we find to be $a^* > 0.92$ (99% statistical uncertainty, based on an idealized lamppost geometry)., 23 pages, 16 figures, accepted for publication in ApJ

Published
2017

36. NuSTAR reveals the extreme properties of the super-Eddington accreting supermassive black hole in PG 1247+267

Author

Duncan Farrah, Franz E. Bauer, M. Cappi, W. N. Brandt, W. W. Zhang, Giorgio Lanzuisi, M. Dadina, Enrico Piconcelli, Fausto Vagnetti, Andrea Comastri, C. J. Hailey, William W. Craig, S. E. Boggs, Fiona A. Harrison, Giorgio Matt, Claudio Ricci, A. C. Fabian, Dom Walton, Andrea Marinucci, F. E. Christensen, Michele Perna, S. Puccetti, David R. Ballantyne, Alberto Masini, D. Stern, C. Vignali, Cristian Saez, B. Luo, Marcella Brusa, Lanzuisi, G., Perna, M., Comastri, A., Cappi, M., Dadina, M., Marinucci, Andrea, Masini, A., Matt, Giorgio, Vagnetti, F., Vignali, C., Ballantyne, D. R., Bauer, F. E., Boggs, S. E., Brandt, W. N., Brusa, M., Christensen, F. E., Craig, W. W., Fabian, A. C., Farrah, D., Hailey, C. J., Harrison, F. A., Luo, B., Piconcelli, E., Puccetti, S., Ricci, C., Saez, C., Stern, D., Walton, D. J., Zhang, W. W., Marinucci, A., Matt, G., Ballantyne, D.R., Bauer, F.E., Boggs, S.E., Brandt, W.N., Christensen, F.E., Craig, W.W., Fabian, A.C., Hailey, C.J., Harrison, F.A., Walton, D.J., and Zhang, W.W.

Subjects
Accretion, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Power law, Relativistic disk, Quasars: individual: PG 1247+267, Accretion, accretion disk, Settore FIS/05 - Astronomia e Astrofisica, individual: PG 1247+267 [Quasars], Ionization, 0103 physical sciences, Cutoff, Emission spectrum, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Galaxies: nuclei, Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Quasar, Plasma, Galaxies: active, Astronomy and Astrophysic, Redshift, Space and Planetary Science, nuclei [Galaxies], Accretion disks
Abstract

PG1247+267 is one of the most luminous known quasars at z similar to 2 and is a strongly super-Eddington accreting supermassive black hole (SMBH) candidate. We obtained NuSTAR data of this intriguing source in December 2014 with the aim of studying its high-energy emission, leveraging the broad band covered by the new NuSTAR and the archival XMM-Newton data. Several measurements are in agreement with the super-Eddington scenario for PG1247+267: the soft power law (Gamma = 2.3 +/- 0.1); the weak ionized Fe emission line; and a hint of the presence of outflowing ionized gas surrounding the SMBH. The presence of an extreme reflection component is instead at odds with the high accretion rate proposed for this quasar. This can be explained with three different scenarios; all of them are in good agreement with the existing data, but imply very different conclusions: i) a variable primary power law observed in a low state, superimposed on a reflection component echoing a past, higher flux state; ii) a power law continuum obscured by an ionized, Compton thick, partial covering absorber; and iii) a relativistic disk reflector in a lamp-post geometry, with low coronal height and high BH spin. The first model is able to explain the high reflection component in terms of variability. The second does not require any reflection to reproduce the hard emission, while a rather low high-energy cutoff of similar to 100 keV is detected for the first time in such a high redshift source. The third model require a face-on geometry, which may affect the SMBH mass and Eddington ratio measurements. Deeper X-ray broad-band data are required in order to distinguish between these possibilities.

Published
2016
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37. A 78 Day X-ray Period Detected from NGC 5907 ULX1 by Swift

Author

Timothy P.L. Roberts, Fiona A. Harrison, A. C. Fabian, Lian Tao, N. A. Webb, Matteo Bachetti, N. Gehrels, D. Stern, F. Fuerst, Didier Barret, Dom Walton, Murray Brightman, Matthew Middleton, M. Heida, V. Rana, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), ITA, USA, GBR, and FRA

Subjects
Swift, Period (periodic table), [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], black hole physics, FOS: Physical sciences, Flux, Astrophysics, 01 natural sciences, X-rays: binaries, 0103 physical sciences, 010303 astronomy & astrophysics, computer.programming_language, High Energy Astrophysical Phenomena (astro-ph.HE), Current time, Physics, 010308 nuclear & particles physics, X-ray, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Monitoring program, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], computer, X-rays: individual
Abstract

We report the detection of a $78.1\pm0.5$ day period in the X-ray lightcurve of the extreme ultraluminous X-ray source NGC 5907 ULX1 ($L_{\rm{X,peak}}\sim5\times10^{40}$ erg s$^{-1}$), discovered during an extensive monitoring program with Swift. These periodic variations are strong, with the observed flux changing by a factor of $\sim$3-4 between the peaks and the troughs of the cycle; our simulations suggest that the observed periodicity is detected comfortably in excess of 3$\sigma$ significance. We discuss possible origins for this X-ray period, but conclude that at the current time we cannot robustly distinguish between orbital and super-orbital variations., Comment: 6 pages, 3 figures, accepted for publication in ApJL

Published
2016
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38. NuSTARand Swift observations of the very high state in GX 339-4: Weighing the black hole with X-rays

Author

J. A. Kennea, F. Fuerst, Didier Barret, W. W. Zhang, D. Stern, Fiona A. Harrison, A. C. Fabian, S. E. Boggs, John A. Tomsick, Jon M. Miller, P. Romano, F. E. Christensen, Dom Walton, C. J. Hailey, William W. Craig, Victoria Grinberg, and Michael Parker

Subjects
Swift, X-ray spectra, X-ray binary stars, statistical errors, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, continuum fitting method, Astrophysics, Stellar radiation and spectra, 01 natural sciences, stellar spectra, statistical analysis, 0103 physical sciences, black hole spin, Spectral fitting, Swift observation data, 010303 astronomy & astrophysics, computer.programming_language, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, disk spectrum, 010308 nuclear & particles physics, X-ray spectrum, Astronomy and Astrophysics, black holes, physical parameters, X-ray binaries, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, spectral fitting, Astrophysics - High Energy Astrophysical Phenomena, Nuclear Spectroscopic Telescope Array observation data, computer, relativistic reflection modeling
Abstract

We present results from spectral fitting of the very high state of GX~339-4 with NuSTAR and Swift. We use relativistic reflection modelling to measure the spin of the black hole and inclination of the inner disk, and find a spin of $a=0.95^{+0.02}_{-0.08}$ and inclination of $30${\deg}$\pm1$ (statistical errors). These values agree well with previous results from reflection modelling. With the exceptional sensitivity of NuSTAR at the high-energy side of the disk spectrum, we are able to constrain multiple physical parameters simultaneously using continuum fitting. By using the constraints from reflection as input for the continuum fitting method, we invert the conventional fitting procedure to estimate the mass and distance of GX~339-4 using just the X-ray spectrum, finding a mass of $9.0^{+1.6}_{-1.2}M_\odot$ and distance of $8.4\pm0.9$ kpc (statistical errors)., Comment: 6 pages, 4 figures, accepted for publication in ApJ Letters

Published
2016
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39. Multiple cyclotron line-forming regions in GX 301−2

Author

Sebastian Falkner, Brian W. Grefenstette, Katja Pottschmidt, Peter Kretschmar, Dom Walton, Diana M. Marcu-Cheatham, John A. Tomsick, Felix Fürst, and Lorenzo Natalucci

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Accretion (meteorology), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Gaussian, Cyclotron, Continuum (design consultancy), Phase (waves), FOS: Physical sciences, Binary number, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, law.invention, symbols.namesake, Space and Planetary Science, law, 0103 physical sciences, symbols, Astrophysics - High Energy Astrophysical Phenomena, Relativistic quantum chemistry, 010303 astronomy & astrophysics, Line (formation)
Abstract

We present two observations of the high-mass X-ray binary GX 301-2 with NuSTAR, taken at different orbital phases and different luminosities. We find that the continuum is well described by typical phenomenological models, like a very strongly absorbed NPEX model. However, for a statistically acceptable description of the hard X-ray spectrum we require two cyclotron resonant scattering features (CRSF), one at ~35 keV and the other at ~50 keV. Even though both features strongly overlap, the good resolution and sensitivity of NuSTAR allows us to disentangle them at >=99.9% significance. This is the first time that two CRSFs are seen in GX 301-2. We find that the CRSFs are very likely independently formed, as their energies are not harmonically related and, if it were a single line, the deviation from a Gaussian shape would be very large. We compare our results to archival Suzaku data and find that our model also provides a good fit to those data. We study the behavior of the continuum as well as the CRSF parameters as function of pulse phase in seven phase bins. We find that the energy of the 35 keV CRSF varies smoothly as function of phase, between 30-38 keV. To explain this variation, we apply a simple model of the accretion column, taking the altitude of the line-forming region, the velocity of the in-falling material, and the resulting relativistic effects into account. We find that in this model the observed energy variation can be explained simply due to a variation of the projected velocity and beaming factor of the line forming region towards us., 18 pages, 10 figures, accepted for publication in A&A

Published
2018
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40. The hard X-ray emission of the luminous infrared galaxy NGC 6240 as observed by NuSTAR

Author

Simonetta Puccetti, W. N. Brandt, Franz E. Bauer, Luca Zappacosta, D. Stern, Dom Walton, Andrea Marinucci, Fabrizio Fiore, C. J. Hailey, William W. Craig, C. M. Urry, S. E. Boggs, Murray Brightman, Mislav Baloković, Andrea Comastri, Fiona A. Harrison, W. W. Zhang, F. E. Christensen, A. Annuar, P. Arévalo, Claudio Ricci, Michael Koss, David M. Alexander, S. La Massa, P. Gandhi, B. Luo, Puccetti, S., Comastri, A., Bauer, F. E., Brandt, W. N., Fiore, F., Harrison, F. A., Luo, B., Stern, D., Urry, C. M., Alexander, D. M., Annuar, A., Arévalo, P., Baloković, M., Boggs, S. E., Brightman, M., Christensen, F. E., Craig, W. W., Gandhi, P., Hailey, C. J., Koss, M. J., La Massa, S., Marinucci, A., Ricci, C., Walton, D. J., Zappacosta, L., and Zhang, W.

Subjects
galaxie [X-rays], Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, individual: NGC 6240 [galaxies], 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Luminous infrared galaxy, astro-ph.HE, Line-of-sight, 010308 nuclear & particles physics, Spatially resolved, X-ray, Compton scattering, Astronomy and Astrophysics, Astronomy and Astrophysic, Galaxy, galaxies [X-rays], Amplitude, Space and Planetary Science, active [galaxies], Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present a broad-band (~0.3-70 keV) spectral and temporal analysis of NuSTAR observations of the luminous infrared galaxy NGC 6240, combined with archival Chandra, XMM-Newton and BeppoSAX data. NGC 6240 is a galaxy in a relatively early merger state with two distinct nuclei separated by ~1."5. Previous Chandra observations have resolved the two nuclei, showing that they are both active and obscured by Compton-thick material. Although they cannot be resolved by NuSTAR, thanks to the unprecedented quality of the NuSTAR data at energies >10 keV, we clearly detect, for the first time, both the primary and the reflection continuum components. The NuSTAR hard X-ray spectrum is dominated by the primary continuum piercing through an absorbing column density which is mildly optically thick to Compton scattering (tau ~ 1.2, N_H ~ 1.5 x 10^(24) cm^-2). We detect moderate hard X-ray (> 10 keV) flux variability up to 20% on short (15-20 ksec) timescales. The amplitude of the variability is maximum at ~30 keV and is likely to originate from the primary continuum of the southern nucleus. Nevertheless, the mean hard X-ray flux on longer timescales (years) is relatively constant. Moreover, the two nuclei remain Compton-thick, although we find evidence of variability of the material along the line of sight with column densities N_H, Comment: 14 pages, 10 figures, accepted for publication in A&A

Published
2015
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41. THE BROADBAND SPECTRAL VARIABILITY OF MCG-6-30-15 OBSERVED BY NUSTAR AND XMM-NEWTON

Author

David R. Ballantyne, Erin Kara, M. Cappi, W. W. Zhang, A. C. Fabian, F. E. Christensen, C. J. Hailey, William W. Craig, Fiona A. Harrison, Daniel Stern, Laura Brenneman, Dom Walton, P. Arévalo, C. S. Reynolds, Michael Parker, Matteo Guainazzi, Giorgio Matt, M. Elvis, Guido Risaliti, G. Miniutti, Andrea Marinucci, S. E. Boggs, Marinucci, A., Matt, Giorgio, Miniutti, G., Guainazzi, M., Parker, M. L., Brenneman, L., Fabian, A. C., Kara, E., Arevalo, P., Ballantyne, D. R., Boggs, S. E., Cappi, M., Christensen, F. E., Craig, W. W., Elvis, M., Hailey, C. J., Harrison, F. A., Reynolds, C. S., Risaliti, G., Stern, D. K., Walton, D. J., and Zhang, W.

Subjects
ACTIVE GALACTIC NUCLEI, Astrophysics::High Energy Astrophysical Phenomena, DUSTY WARM ABSORBER, IRON LINE, FOS: Physical sciences, Flux, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Occultation, individual (MCG-6-30-015) [X-rays], Seyfert [galaxies], 0103 physical sciences, K-ALPHA LINE, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, SEYFERT-1 GALAXIES, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, accretion, accretion disks, Line-of-sight, 010308 nuclear & particles physics, 1 GALAXY MCG-6-30-15, ASTRONOMY, Astronomy and Astrophysics, REFLECTION MODEL, Galaxy, Rotating black hole, Space and Planetary Science, BLACK-HOLE, active [galaxies], X-RAY-SPECTRUM, Astrophysics - High Energy Astrophysical Phenomena, Relativistic quantum chemistry, Event (particle physics), PHOTON IMAGING CAMERA
Abstract

MCG-6-30-15, at a distance of 37 Mpc (z=0.008), is the archetypical Seyfert 1 galaxy showing very broad Fe K$\alpha$ emission. We present results from a joint NuSTAR and XMM-Newton observational campaign that, for the first time, allows a sensitive, time-resolved spectral analysis from 0.35 keV up to 80 keV. The strong variability of the source is best explained in terms of intrinsic X-ray flux variations and in the context of the light bending model: the primary, variable emission is reprocessed by the accretion disk, which produces secondary, less variable, reflected emission. The broad Fe K$\alpha$ profile is, as usual for this source, well explained by relativistic effects occurring in the innermost regions of the accretion disk around a rapidly rotating black hole. We also discuss the alternative model in which the broadening of the Fe K$\alpha$ is due to the complex nature of the circumnuclear absorbing structure. Even if this model cannot be ruled out, it is disfavored on statistical grounds. We also detected an occultation event likely caused by BLR clouds crossing the line of sight., Comment: 19 pages, 16 figures, accepted for publication on ApJ

Published
2014
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42. The Large Observatory For x-ray Timing

Author

Antonios Manousakis, S. Boutloukos, F. Zwart, Jose M. Torrejon, C. Pittori, Alessandro Drago, Dieter H. Hartmann, Feryal Özel, T. J. L. Courvoisier, Tim Johannsen, Jordi José, M. Michalska, Christian Schmid, I. Rashevskaya, Gottfried Kanbach, V. Petracek, L. Bradley, Allan Hornstrup, M. H. Erkut, Sergio Campana, Rudy Wijnands, Andrew Cumming, Nils Andersson, Tomaso Belloni, M. C. Miller, Roman Wawrzaszek, Stefano Bianchi, Enrique García-Berro, Sandro Mereghetti, C. Guidorzi, C. Corral Van Damme, Søren Brandt, Francesco Tombesi, Felix Ryde, Didier Barret, Simon Vaughan, Marco Feroci, T. Di Salvo, C. van Baren, Angelo Antonelli, Marc Ribó, J. L. Atteia, P. Soleri, Alessio Trois, Silvia Zane, G. Mouret, Ersin Gogus, Emanuele Perinati, J. Coker, Piero Malcovati, V. Mangano, F. Jetter, P. Uter, P. Romano, M. Nowak, Roberto Turolla, Laura Tolos, Antonino D'Ai, Laura Alvarez, C. Amoros, Simone Scaringi, A. Possenti, David M. Smith, M. Falanga, A. Goldwurm, René Hudec, Ignacio Negueruela, M. van der Klis, Francesco Longo, José A. Pons, I. M. McHardy, R. Rohlfs, P. Cais, Luigi Stella, S. Di Cosimo, Antoine Rousseau, M. Ayre, M. Gschwender, D. Klochkov, Niels Lund, Chryssa Kouveliotou, P. Azzarello, F. Château, Michael Gabler, S. Vercellone, Martin Durant, I. Donnarumma, Giorgio Matt, Mauro Orlandini, P. Kaaret, Patrick Smith, P. T. O'Brien, A. Argan, M. Orienti, Marco Grassi, Claudio Labanti, Edward F. Brown, Christopher S. Reynolds, Gloria Sala, Y. Evangelista, Gabriel Török, José Braga, Riccardo Campana, Alan Smith, C. Gouiffes, Nevin N. Weinberg, Leonardo Gualtieri, Yannick Favre, P.G. Jonker, Gabriele Giovannini, D. de Martino, Irfan Kuvvetli, S. Motta, Teresa Mineo, Paul J. Groot, Pablo Reig, Martino Marisaldi, Andrea Sanna, Lorenzo Amati, G. L. Israel, D. Macera, K. S. Wood, Pablo Cerdá-Durán, F. Fuschino, Suvi Gezari, Mariano Mendez, Slawomir Suchy, Damien Rambaud, Nanda Rea, R. Artigue, J.-Y. Seyler, S. N. Shore, Frederick K. Lamb, Jörn Wilms, Mark G. Alford, Margarita Hernanz, Thomas M. Tauris, Luca Izzo, Tobias Boenke, J. J. M. in 't Zand, J. Mulačová, P. Binko, Daniel Maier, Jan Schee, Bruce Gendre, Enrico Bozzo, Paul S. Ray, Giuseppe Bertuccio, Simone Migliari, Ignazio Bombaci, Vladimir Karas, Nikolaos Stergioulas, P. P. Laubert, D. Karelin, A. C. Fabian, Giovanni Miniutti, Dacheng Lin, L. Guy, Martine Mouchet, Colleen A. Wilson-Hodge, Valeria Ferrari, Kai Hebeler, Mark H. Finger, Shigeto Watanabe, Pawel Haensel, H. Jacobs, Adrian Martindale, A. A. Zdziarski, Andrea Santangelo, Giuseppe Baldazzi, Piergiorgio Casella, Fabio Muleri, M. Hailey, Antonio Bianchini, Giuseppe Lodato, E. Del Monte, M. Rapisarda, Zdeněk Stuchlík, Alain Cros, V. Sochora, Laurens Keek, Jorge Casares, Andrew Melatos, Pere Blay, E. Rossi, A. P. Spencer, G. Stratta, Conrado Albertus, J. M. Paredes, M. Ahangarianabhari, Anna L. Watts, M. Del Santo, I. Kreykenbohm, Alessandro Patruno, G. A. Caliandro, C. Feldman, M. Pohl, Fabrizio Tamburini, G. Zampa, Marina Orio, Flemming Hansen, P. Ramon, Ruben Salvaterra, David H. Lumb, Edward M. Cackett, Andrew Shearer, Sharon M. Morsink, L. Pacciani, J.-M. Bonnet Bidaud, A. De Luca, Jérôme Chenevez, Sebastian Diebold, N. Zampa, Carole A. Haswell, Luciano Burderi, E. Cavazzuti, Adam Ingram, Dhiren Kataria, Berend Winter, A. Vacchi, W. Hermsen, P. Giommi, Dong Lai, N. A. Webb, P. Bodin, Dom Walton, Solen Balman, Benjamin Stappers, M. Burgay, Luca Zampieri, Carl Budtz-Jørgensen, Ralph A. M. J. Wijers, Giancarlo Cusumano, J. L. Galvez Sanchez, Raffaella Schneider, Luciano Rezzolla, Alexander Heger, S. Korpela, Dimitrios Emmanoulopoulos, Biswajit Paul, Diego Götz, B. Artigues, Paolo Soffitta, M. H. Finger, J. W. den Herder, Paolo Esposito, Kazushi Iwasawa, Poul Erik Holmdahl Olsen, J. Neilsen, Marco Barbera, Deepto Chakrabarty, R. A. Osten, M. Reina Aranda, A. J. Castro-Tirado, Andrea Tramacere, D. Haas, Johannes Dercksen, John A. Tomsick, A. V. Penacchioni, V. D'Elia, Alfonso Collura, Altan Baykal, P. Le Provost, S. Turriziani, Kostas D. Kokkotas, Duncan K. Galloway, Ron Remillard, Juhani Huovelin, Somak Bhattacharyya, Pavel Bakala, Phil Uttley, Richard E. Cole, Mahesh Prakash, L. Kuiper, T. Munoz-Darias, Diego F. Torres, S. Mahmoodifar, G. Ramsay, Andrew Norton, T. Kennedy, Achim Schwenk, L. Zdunik, A. B. Giles, Jerome Rodriguez, C. Motch, Ilya Mandel, Marcello Giroletti, Dimitrios Psaltis, J. Sandberg, Fiamma Capitanio, Remon Cornelisse, M. R. Gilfanov, Peggy Varniere, Franck Cadoux, Peter J. Wheatley, M. de Pasquale, Juri Poutanen, S. Maestre, A. Pellizzoni, Axel Schwope, Diego Altamirano, Piotr Orleanski, V. Vrba, Agata Różańska, Kateřina Goluchová, P. Rodríguez Gil, Niccolò Bucciantini, Stéphane Schanne, Carlo Ferrigno, Thomas J. Maccarone, H. Wende, Tod E. Strohmayer, Tadayuki Takahashi, Francois Lebrun, E. Kuulkers, Jeroen Homan, Maurizio Paolillo, M. A. Perez, J. P. Osborne, A. Alpar, Sanjay Reddy, G.W. Fraser, V. Sulemainov, D. Linder, L. Sabau-Graziati, A. Rachevski, Bing Zhang, Alessandro Papitto, C. Tenzer, Alex Markowitz, J. Portell, Roberto Mignani, Fabrizio Bocchino, Arnau Rios, R. de la Rie, M. Wille, A. de Rosa, Alessandro Riggio, M. Frericks, Andrew W. Steiner, Michal Bursa, Federico Bernardini, Jon M. Miller, W. Kluzniak, INAF - Osservatorio Astronomico di Roma ( OAR ), Istituto Nazionale di Astrofisica ( INAF ), Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées ( LATT ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Variable Energy Cyclotron Centre, Institut Pasteur de Montevideo, Réseau International des Instituts Pasteur ( RIIP ) -Institut Pasteur de Montevideo, Mullard Space Science Laboratory ( MSSL ), University College of London [London] ( UCL ), FORMATION STELLAIRE 2014, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux ( L3AB ), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Observatoire aquitain des sciences de l'univers ( OASU ), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Laboratoire d'Astrophysique de Bordeaux [Pessac] ( LAB ), Université de Bordeaux ( UB ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Bordeaux ( UB ), Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, Interactions et dynamique des environnements de surface ( IDES ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Licryl Laboratory ( CNR-IPCF UOS Cosenza ), University of Calabria, Laboratori Nazionali di Frascati ( LNF ), National Institute for Nuclear Physics ( INFN ), PCAS, Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano ( IASF-MI ), AstroParticule et Cosmologie ( APC - UMR 7164 ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Astrophysique Interactions Multi-échelles ( AIM - UMR 7158 - UMR E 9005 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Paris Diderot - Paris 7 ( UPD7 ), Canada's National Laboratory for Particle and Nuclear Physics ( TRIUMF ), NRC, Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] ( UNIBO ), Institut de recherches sur la catalyse et l'environnement de Lyon ( IRCELYON ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Univers et Théories ( LUTH ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Spectrochimie Infrarouge et Raman - UMR 8516 ( LASIR ), Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), Dipartimento di Scienze Fisiche [Naples], Università degli studi di Napoli Federico II, Energétique, propulsion, espace, environnement ( EPEE ), Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Department of Physics and Astronomy [Hanover], Dartmouth College [Hanover], Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d’Optique Atmosphérique - UMR 8518 ( LOA ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), Institut de Biologie du Développement de Marseille ( IBDM ), Aix Marseille Université ( AMU ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ), Universitat Politècnica de Catalunya [Barcelona] ( UPC ), INAF-IASF Milano, Climate and Environmental Physics [Bern], University of Bern, Centre National d'Etudes Spatiales ( CNES ), Institute of Geology, Eidgenössische Technische Hochschule [Zürich] ( ETH Zürich ), IEEC-CSIC, Universitat Autònoma de Barcelona [Barcelona] ( UAB ), MedisysResearch Lab ( Medisys ), Philips Research, European Space Astronomy Center ( ESAC ), European Space Agency ( ESA ), High Energy Astrophys. & Astropart. Phys (API, FNWI), INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Réseau International des Instituts Pasteur (RIIP), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Licryl Laboratory (CNR-IPCF UOS Cosenza), Università della Calabria [Arcavacata di Rende] (Unical), Laboratori Nazionali di Frascati (LNF), Istituto Nazionale di Fisica Nucleare (INFN), Istituto di Astrofisica Spaziale e Fisica Cosmica - Milano (IASF-MI), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Canada's particle accelerator centre (TRIUMF), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRE), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), University of Naples Federico II = Università degli studi di Napoli Federico II, Energétique, propulsion, espace, environnement (EPEE), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie du Développement de Marseille (IBDM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Universitat Politècnica de Catalunya [Barcelona] (UPC), Climate and Environmental Physics [Bern] (CEP), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE), Centre National d'Études Spatiales [Toulouse] (CNES), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Universitat Autònoma de Barcelona (UAB), MedisysResearch Lab (Medisys), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), SPIE, Takahashi, Tadayuki, Feroci M., Den Herder J.W., Bozzo E., Barret D., Brandt S., Hernanz M., Van Der Klis M., Pohl M., Santangelo A., Stella L., Watts A., Wilms J., Zane S., Ahangarianabhari M., Albertus C., Alford M., Alpar A., Altamirano D., Alvarez L., Amati L., Amoros C., Andersson N., Antonelli A., Argan A., Artigue R., Artigues B., Atteia J.-L., Azzarello P., Bakala P., Baldazzi G., Balman S., Barbera M., Van Baren C., Bhattacharyya S., Baykal A., Belloni T., Bernardini F., Bertuccio G., Bianchi S., Bianchini A., Binko P., Blay P., Bocchino F., Bodin P., Bombaci I., Bonnet Bidaud J.-M., Boutloukos S., Bradley L., Braga J., Brown E., Bucciantini N., Burderi L., Burgay M., Bursa M., Budtz-Jorgensen C., Cackett E., Cadoux F.R., Cais P., Caliandro G.A., Campana R., Campana S., Capitanio F., Casares J., Casella P., Castro-Tirado A.J., Cavazzuti E., Cerda-Duran P., Chakrabarty D., Chateau F., Chenevez J., Coker J., Cole R., Collura A., Cornelisse R., Courvoisier T., Cros A., Cumming A., Cusumano G., D'ai A., D'elia V., Del Monte E., De Luca A., De Martino D., Dercksen J.P.C., De Pasquale M., De Rosa A., Del Santo M., Di Cosimo S., Diebold S., Di Salvo T., Donnarumma I., Drago A., Durant M., Emmanoulopoulos D., Erkut M.H., Esposito P., Evangelista Y., Fabian A., Falanga M., Favre Y., Feldman C., Ferrari V., Ferrigno C., Finger M., Finger M.H., Fraser G.W., Frericks M., Fuschino F., Gabler M., Galloway D.K., Galvez Sanchez J.L., Garcia-Berro E., Gendre B., Gezari S., Giles A.B., Gilfanov M., Giommi P., Giovannini G., Giroletti M., Gogus E., Goldwurm A., Goluchova K., Gotz D., Gouiffes C., Grassi M., Groot P., Gschwender M., Gualtieri L., Guidorzi C., Guy L., Haas D., Haensel P., Hailey M., Hansen F., Hartmann D.H., Haswell C.A., Hebeler K., Heger A., Hermsen W., Homan J., Hornstrup A., Hudec R., Huovelin J., Ingram A., In't Zand J.J.M., Israel G., Iwasawa K., Izzo L., Jacobs H.M., Jetter F., Johannsen T., Jonker P., Jose J., Kaaret P., Kanbach G., Karas V., Karelin D., Kataria D., Keek L., Kennedy T., Klochkov D., Kluzniak W., Kokkotas K., Korpela S., Kouveliotou C., Kreykenbohm I., Kuiper L.M., Kuvvetli I., Labanti C., Lai D., Lamb F.K., Laubert P.P., Lebrun F., Lin D., Linder D., Lodato G., Longo F., Lund N., Maccarone T.J., Macera D., Maestre S., Mahmoodifar S., Maier D., Malcovati P., Mandel I., Mangano V., Manousakis A., Marisaldi M., Markowitz A., Martindale A., Matt G., Mchardy I.M., Melatos A., Mendez M., Mereghetti S., Michalska M., Migliari S., Mignani R., Miller M.C., Miller J.M., Mineo T., Miniutti G., Morsink S., Motch C., Motta S., Mouchet M., Mouret G., Mulaova J., Muleri F., Munoz-Darias T., Negueruela I., Neilsen J., Norton A.J., Nowak M., O'brien P., Olsen P.E.H., Orienti M., Orio M., Orlandini M., Orleaaski P., Osborne J.P., Osten R., Ozel F., Pacciani L., Paolillo M., Papitto A., Paredes J.M., Patruno A., Paul B., Perinati E., Pellizzoni A., Penacchioni A.V., Perez M.A., Petracek V., Pittori C., Pons J., Portell J., Possenti A., Poutanen J., Prakash M., Le Provost P., Psaltis D., Rambaud D., Ramon P., Ramsay G., Rapisarda M., Rachevski A., Rashevskaya I., Ray P.S., Rea N., Reddy S., Reig P., Reina Aranda M., Remillard R., Reynolds C., Rezzolla L., Ribo M., De La Rie R., Riggio A., Rios A., Rodriguez-Gil P., Rodriguez J., Rohlfs R., Romano P., Rossi E.M.R., Rozanska A., Rousseau A., Ryde F., Sabau-Graziati L., Sala G., Salvaterra R., Sanna A., Sandberg J., Scaringi S., Schanne S., Schee J., Schmid C., Shore S., Schneider R., Schwenk A., Schwope A.D., Seyler J.-Y., Shearer A., Smith A., Smith D.M., Smith P.J., Sochora V., Soffitta P., Soleri P., Spencer A., Stappers B., Steiner A.W., Stergioulas N., Stratta G., Strohmayer T.E., Stuchlik Z., Suchy S., Sulemainov V., Takahashi T., Tamburini F., Tauris T., Tenzer C., Tolos L., Tombesi F., Tomsick J., Torok G., Torrejon J.M., Torres D.F., Tramacere A., Trois A., Turolla R., Turriziani S., Uter P., Uttley P., Vacchi A., Varniere P., Vaughan S., Vercellone S., Vrba V., Walton D., Watanabe S., Wawrzaszek R., Webb N., Weinberg N., Wende H., Wheatley P., Wijers R., Wijnands R., Wille M., Wilson-Hodge C.A., Winter B., Wood K., Zampa G., Zampa N., Zampieri L., Zdunik L., Zdziarski A., Zhang B., Zwart F., Ayre M., Boenke T., Corral Van Damme C., Kuulkers E., Lumb D., Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille Institut (CLIL), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Universität Bern [Bern]-Universität Bern [Bern], European Space Agency (ESA), Feroci, M., den Herder, J., Bozzo, E., Barret, D., Brandt, S., Hernanz, M., van der Klis, M., Pohl, M., Santangelo, A., Stella, L., Watts, A., Wilms, J., Zane, S., Ahangarianabhari, M., Albertus, C., Alford, M., Alpar, A., Altamirano, D., Alvarez, L., Amati, L., Amoros, C., Andersson, N., Antonelli, A., Argan, A., Artigue, R., Artigues, B., Atteia, J., Azzarello, P., Bakala, P., Baldazzi, G., Balman, S., Barbera, M., van Baren, C., Bhattacharyya, S., Baykal, A., Belloni, T., Bernardini, F., Bertuccio, G., Bianchi, S., Bianchini, A., Binko, P., Blay, P., Bocchino, F., Bodin, P., Bombaci, I., Bonnet Bidaud, J., Boutloukos, S., Bradley, L., Braga, J., Brown, E., Bucciantini, N., Burderi, L., Burgay, M., Bursa, M., Budtz Jørgensen, C., Cackett, E., Cadoux, F., Caïs, P., Caliandro, G., Campana, R., Campana, S., Capitanio, F., Casares, J., Casella, P., Castro Tirado, A., Cavazzuti, E., Cerda Duran, P., Chakrabarty, D., Château, F., Chenevez, J., Coker, J., Cole, R., Collura, A., Cornelisse, R., Courvoisier, T., Cros, A., Cumming, A., Cusumano, G., D'Ai', A., D'Elia, V., Del Monte, E., de Luca, A., de Martino, D., Dercksen, J., de Pasquale, M., De Rosa, A., Del Santo, M., Di Cosimo, S., Diebold, S., DI SALVO, T., Donnarumma, I., Drago, A., Durant, M., Emmanoulopoulos, D., Erkut, M., Esposito, P., Evangelista, Y., Fabian, A., Falanga, M., Favre, Y., Feldman, C., Ferrari, V., Ferrigno, C., Finger, M., Fraser, G., Frericks, M., Fuschino, F., Gabler, M., Galloway, D., Galvez Sanchez, J., Garcia Berro, E., Gendre, B., Gezari, S., Giles, A., Gilfanov, M., Giommi, P., Giovannini, G., Giroletti, M., Gogus, E., Goldwurm, A., Goluchová, K., Götz, D., Gouiffes, C., Grassi, M., Groot, P., Gschwender, M., Gualtieri, L., Guidorzi, C., Guy, L., Haas, D., Haensel, P., Hailey, M., Hansen, F., Hartmann, D., Haswell, C., Hebeler, K., Heger, A., Hermsen, W., Homan, J., Hornstrup, A., Hudec, R., Huovelin, J., Ingram, A., In't Zand, J., Israel, G., Iwasawa, K., Izzo, L., Jacobs, H., Jetter, F., Johannsen, T., Jonker, P., Josè, J., Kaaret, P., Kanbach, G., Karas, V., Karelin, D., Kataria, D., Keek, L., Kennedy, T., Klochkov, D., Kluzniak, W., Kokkotas, K., Korpela, S., Kouveliotou, C., Kreykenbohm, I., Kuiper, L., Kuvvetli, I., Labanti, C., Lai, D., Lamb, F., Laubert, P., Lebrun, F., Lin, D., Linder, D., Lodato, G., Longo, F., Lund, N., Maccarone, T., Macera, D., Maestre, S., Mahmoodifar, S., Maier, D., Malcovati, P., Mandel, I., Mangano, V., Manousakis, A., Marisaldi, M., Markowitz, A., Martindale, A., Matt, G., Mchardy, I., Melatos, A., Mendez, M., Mereghetti, S., Michalska, M., Migliari, S., Mignani, R., Miller, M., Miller, J., Mineo, T., Miniutti, G., Morsink, S., Motch, C., Motta, S., Mouchet, M., Mouret, G., Mulačová, J., Muleri, F., Muñoz Darias, T., Negueruela, I., Neilsen, J., Norton, A., Nowak, M., O'Brien, P., Olsen, P., Orienti, M., Orio, M., Orlandini, M., Orleański, P., Osborne, J., Osten, R., Ozel, F., Pacciani, L., Paolillo, M., Papitto, A., Paredes, J., Patruno, A., Paul, B., Perinati, E., Pellizzoni, A., Penacchioni, A., Perez, M., Petracek, V., Pittori, C., Pons, J., Portell, J., Possenti, A., Poutanen, J., Prakash, M., Le Provost, P., Psaltis, D., Rambaud, D., Ramon, P., Ramsay, G., Rapisarda, M., Rachevski, A., Rashevskaya, I., Ray, P., Rea, N., Reddy, S., Reig, P., Reina Aranda, M., Remillard, R., Reynolds, C., Rezzolla, L., Ribo, M., de la Rie, R., Riggio, A., Rios, A., Rodríguez Gil, P., Rodriguez, J., Rohlfs, R., Romano, P., Rossi, E., Rozanska, A., Rousseau, A., Ryde, F., Sabau Graziati, L., Sala, G., Salvaterra, R., Sanna, A., Sandberg, J., Scaringi, S., Schanne, S., Schee, J., Schmid, C., Shore, S., Schneider, R., Schwenk, A., Schwope, A., Seyler, J., Shearer, A., Smith, A., Smith, D., Smith, P., Sochora, V., Soffitta, P., Soleri, P., Spencer, A., Stappers, B., Steiner, A., Stergioulas, N., Stratta, G., Strohmayer, T., Stuchlik, Z., Suchy, S., Sulemainov, V., Takahashi, T., Tamburini, F., Tauris, T., Tenzer, C., Tolos, L., Tombesi, F., Tomsick, J., Torok, G., Torrejon, J., Torres, D., Tramacere, A., Trois, A., Turolla, R., Turriziani, S., Uter, P., Uttley, P., Vacchi, A., Varniere, P., Vaughan, S., Vercellone, S., Vrba, V., Walton, D., Watanabe, S., Wawrzaszek, R., Webb, N., Weinberg, N., Wende, H., Wheatley, P., Wijers, R., Wijnands, R., Wille, M., Wilson Hodge, C., Winter, B., Wood, K., Zampa, G., Zampa, N., Zampieri, L., Zdunik, L., Zdziarski, A., Zhang, B., Zwart, F., Ayre, M., Boenke, T., Corral van Damme, C., Kuulkers, E., Lumb, D., Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), National Institute for Nuclear Physics (INFN), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Canada's National Laboratory for Particle and Nuclear Physics (TRIUMF), Università di Bologna [Bologna] (UNIBO), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Spectrochimie Infrarouge et Raman - UMR 8516 (LASIR), Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Aix Marseille Université (AMU)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Universitat Autònoma de Barcelona [Barcelona] (UAB), Astronomy, den Herder, J. W., Atteia, J. L., Bonnet Bidaud, J. M., Cadoux, F. R., Cais, P., Caliandro, G. A., Castro Tirado, A. J., D'Aì, A., De Luca, A., De Martino, D., Dercksen, J. P. C., De Pasquale, M., Di Salvo, T., Erkut, M. H., Finger, M. H., Fraser, G. W., Galloway, D. K., Galvez Sanchez, J. L., Giles, A. B., Hartmann, D. H., Haswell, C. A., in't Zand, J. J. M., Jacobs, H. M., Kuiper, L. M., Lamb, F. K., Laubert, P. P., Maccarone, T. J., Mchardy, I. M., Miller, M. C., Miller, J. M., Norton, A. J., Olsen, P. E. H., Orleanski, P., Osborne, J. P., Paolillo, Maurizio, Paredes, J. M., Penacchioni, A. V., Perez, M. A., Ray, P. S., Rossi, E. M. R., Schwope, A. D., Seyler, J. Y., Smith, D. M., Smith, P. J., Steiner, A. W., Strohmayer, T. E., Torrejon, J. M., Torres, D. F., and Wilson Hodge, C. A.

Subjects
x-ray and γ-ray instrumentation, compact objects, microchannel plates, X-ray detectors, X-ray imaging, X-ray spectroscopy, X-ray timing, Electronic, Optical and Magnetic Materials, Condensed Matter Physics, Computer Science Applications1707 Computer Vision and Pattern Recognition, Applied Mathematics, Electrical and Electronic Engineering, Vision, Observatories, Field of view, 01 natural sciences, 7. Clean energy, neutron stars, Observatory, 010303 astronomy & astrophysics, Physics, Equipment and services, Astrophysics::Instrumentation and Methods for Astrophysics, Steradian, [ SDU.ASTR.IM ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Astrophysics - Instrumentation and Methods for Astrophysics, X-ray detector, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Cosmic Vision, Spectral resolution, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, NO, microchannel plate, Settore FIS/05 - Astronomia e Astrofisica, X-rays, compact object, 0103 physical sciences, Electronic, Optical and Magnetic Materials, Instrumentation and Methods for Astrophysics (astro-ph.IM), dense hadronic matter, Sensors, 010308 nuclear & particles physics, Astronomy, Accretion (astrophysics), [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Neutron star, 13. Climate action, [ PHYS.ASTR.IM ] Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Gamma-ray burst, astro-ph.IM
Abstract

The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final down-selection for a launch slot in 2022-2024. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument, LOFT will study the behaviour of matter under extreme conditions, such as the strong gravitational field in the innermost regions of accretion flows close to black holes and neutron stars, and the supra-nuclear densities in the interior of neutron stars. The science payload is based on a Large Area Detector (LAD, 10 m 2 effective area, 2-30 keV, 240 eV spectral resolution, 1 deg collimated field of view) and a WideField Monitor (WFM, 2-50 keV, 4 steradian field of view, 1 arcmin source location accuracy, 300 eV spectral resolution). The WFM is equipped with an on-board system for bright events (e.g. GRB) localization. The trigger time and position of these events are broadcast to the ground within 30 s from discovery. In this paper we present the status of the mission at the end of its Phase A study., Proc. SPIE 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 91442T

Published
2014
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43. A large area detector proposed for the Large Observatory for X-ray Timing (LOFT)

Author

I. Donnarumma, Y. Evangelista, Phil Uttley, Christian Schmid, D. Macera, L. Pacciani, Paul S. Smith, T. Kennedy, J.-Y. Seyler, J. W. den Herder, Martino Marisaldi, Michael A. Nowak, A. de Rosa, Berend Winter, Dom Walton, E. Bozzo, A. Argan, Miriam Grassi, C. Tenzer, M. Ahangarianabhari, G. Zampa, Andrea Santangelo, Jörn Wilms, A. Vacchi, P. Bodini, Riccardo Campana, Claudio Labanti, Slawomir Suchy, Silvia Zane, P. Soffitta, F. Fuschino, Fabio Muleri, M. Hailey, S. Di Cosimo, Adrian Martindale, V. Petracek, P. Cais, Giuseppe Baldazzi, Yannick Favre, Mauro Orlandini, E. Del Monte, Didier Barret, Alain Cros, Emanuele Perinati, C. Feldman, M. Pohl, Franck Cadoux, J. Coker, Piero Malcovati, M. Feroci, René Hudec, P. Azzarello, Teresa Mineo, A. Rachevski, G.W. Fraser, Giuseppe Bertuccio, N. Zampa, SPIE, Takahashi, Tadayuki, Zane S., Walton D., Kennedy T., Feroci M., Den Herder J.-W., Ahangarianabhari M., Argan A., Azzarello P., Baldazzi G., Barret D., Bertuccio G., Bodin P., Bozzo E., Cadoux F., Cais P., Campana R., Coker J., Cros A., Del Monte E., De Rosa A., Di Cosimo S., Donnarumma I., Evangelista Y., Favre Y., Feldman C., Fraser G., Fuschino F., Grassi M., Hailey M.R., Hudec R., Labanti C., Macera D., Malcovati P., Marisaldi M., Martindale A., Mineo T., Muleri F., Nowak M., Orlandini M., Pacciani L., Perinati E., Petracek V., Pohl M., Rachevski A., Smith P., Santangelo A., Seyler J.-Y., Schmid C., Soffitta P., Suchy S., Tenzer C., Uttley P., Vacchi A., Zampa G., Zampa N., Wilms J., Winter B., High Energy Astrophys. & Astropart. Phys (API, FNWI), FORMATION STELLAIRE 2012, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Mullard Space Science Laboratory (MSSL), and University College of London [London] (UCL)

Subjects
Silicon, Photon, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Observatories, Collimators, FOS: Physical sciences, ddc:500.2, Astrophysics, 7. Clean energy, 01 natural sciences, Optics, Observatory, 0103 physical sciences, X-rays, Electronic, Optical and Magnetic Materials, Electrical and Electronic Engineering, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Compact objects, Physics, Millisecond, Photons, Equipment and services, sezele, 010308 nuclear & particles physics, Payload, business.industry, Sensors, Applied Mathematics, Detector, Antenna aperture, Computer Science Applications1707 Computer Vision and Pattern Recognition, Condensed Matter Physics, Capillaries, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Neutron star, X-ray Timing, Electronic, Optical and Magnetic Materials, Instrumentation and Methods for Astrophysics, business, Astrophysics - Instrumentation and Methods for Astrophysics, Energy (signal processing), Compact object
Abstract

The Large Observatory for X-ray Timing (LOFT) is one of the four candidate ESA M3 missions considered for launch in the 2022 time-frame. It is specifically designed to perform fast X-ray timing and probe the status of the matter near black holes and neutron stars. The LOFT scientific payload is composed of a Large Area Detector (LAD) and a Wide Field Monitor (WFM). The LAD is a 10 m2-class pointed instrument with 20 times the collecting area of the best past timing missions (such as RXTE) over the 2-30 keV range, which holds the capability to revolutionize studies of X-ray variability down to the millisecond time scales. Its ground-breaking characteristic is a low mass per unit surface, enabling an effective area of ~10 m^2 (@10 keV) at a reasonable weight. The development of such large but light experiment, with low mass and power per unit area, is now made possible by the recent advancements in the field of large-area silicon detectors - able to time tag an X-ray photon with an accuracy, Proceedings of SPIE, Vo. 8443, Paper No. 8443-87

Published
2012
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44. Discovery and analysis of a ULX nebula in NGC 3521

Author

Dom Walton, Peter G. Jonker, K. M. López, Fiona A. Harrison, Marianne Heida, Manuel A. P. Torres, Dae-Sik Moon, and Timothy P.L. Roberts

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Photosphere, Very Large Telescope, Nebula, Astronomy, Metallicity, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Luminosity, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Emission spectrum, Astrophysics - High Energy Astrophysical Phenomena, 010306 general physics, 010303 astronomy & astrophysics, Line (formation)
Abstract

We present Very Large Telescope/X-shooter and Chandra X-ray observatory/ACIS observations of the ULX [SST2011] J110545.62+000016.2 in the galaxy NGC 3521. The source identified as a candidate near-infrared counterpart to the ULX in our previous study shows an emission line spectrum of numerous recombination and forbidden lines in the visible and near-infrared spectral regime. The emission from the candidate counterpart is spatially extended ($\sim$ 34 pc) and appears to be connected with an adjacent H II region, located $\sim$ 138 pc to the NE. The measured velocities of the emission lines confirm that both the candidate counterpart and H II region reside in NGC 3521. The intensity ratios of the emission lines from the ULX counterpart show that the line emission originates from the combined effect of shock and photoionisation of low metallicity (12 + log (O/H) = 8.19 $\pm$ 0.11) gas. Unfortunately, there is no identifiable spectral signature directly related to the photosphere of the mass-donor star in our spectrum. From the archival Chandra data, we derive the X-ray luminosity of the source in the 0.3-7 keV range to be (1.9 $\pm$ 0.8) $\times$ 10$^{40}$ erg cm$^{-2}$ s$^{-1}$, almost a factor of four higher than what is previously reported., Comment: 17 pages, 10 figures, accepted for publication in MNRAS

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