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We present new X-ray observations of luminous heavily dust-reddened quasars (HRQs) selected from infrared sky surveys. HRQs appear to be a dominant population at high redshifts and the highest luminosities, and may be associated with a transitional "blowout" phase of black hole and galaxy co-evolution models. Despite this, their high-energy properties have been poorly known. We use the overall sample of $10$ objects with XMM-Newton coverage to study the high-energy properties of HRQs at $\left< L_{\rm bol} \right> = 10^{47.5}$ erg/s and $\left< z \right>= 2.5$. For the seven sources with strong X-ray detections, we perform spectral analyses. These find a median X-ray luminosity of $\left< L_{\rm 2-10\,keV} \right> = 10^{45.1}$ erg/s, comparable to the most powerful X-ray quasars known. The gas column densities are $N_{\rm H}=(1$-$8)\times 10^{22}$ cm$^{-2}$, in agreement with the amount of dust extinction observed. The dust to gas ratios are sub-Galactic, but are higher than found in local AGN. The intrinsic X-ray luminosities of HRQs are weak compared to the mid-infrared ($L_{\rm 6\mu m}$) and bolometric luminosities ($L_{\rm bol}$), in agreement with findings for other luminous quasar samples. For instance, the X-ray to bolometric corrections range from $\kappa_{\rm bol}\approx 50$-$3000$. The moderate absorption levels and accretion rates close to the Eddington limit ($\left< \lambda_{\rm Edd} \right>=1.06$) are in agreement with a quasar blowout phase. Indeed, we find that the HRQs lie in the forbidden region of the $N_{\rm H}$-$\lambda_{\rm Edd}$ plane, and therefore that radiation pressure feedback on the dusty interstellar medium may be driving a phase of blowout that has been ongoing for a few $10^{5}$ years. The wider properties, including [OIII] narrow-line region kinematics, broadly agree with this interpretation., Comment: In press. Accepted for publication in MNRAS

We present new Karl G. Jansky Very Large Array (VLA, 1.5 GHz) radio data for the giant elliptical galaxy IC 4296, supported by archival radio, X-ray (Chandra, XMM-Newton) and optical (SOAR, HST) observations. The galaxy hosts powerful radio jets piercing through the inner hot X-ray emitting atmosphere, depositing most of the energy into the ambient intra-cluster medium (ICM). Whereas the radio surface brightness of the A configuration image is consistent with a Fanaroff-Riley Class I (FR I) system, the D configuration image shows two bright, relative to the central region, large (~160 kpc diameter), well-defined lobes, previously reported by Killeen et al., at a projected distance r~>230 kpc. The XMM-Newton image reveals an X-ray cavity associated with one of the radio lobes. The total enthalpy of the radio lobes is ~7x10^59 erg and the mechanical power output of the jets is ~10^44 erg/s. The jets are mildly curved and possibly re-brightened by the relative motion of the galaxy and the ICM. The lobes display sharp edges, suggesting the presence of bow shocks, which would indicate that they are expanding supersonically. The central entropy and cooling time of the X-ray gas are unusually low and the nucleus hosts a warm H\alpha+[NII] nebula and a cold molecular CO disk. Because most of the energy of the jets is deposited far from the nucleus, the atmosphere of the galaxy continues to cool, apparently feeding the central supermassive black hole and powering the jet activity., Comment: Accepted for publication in MNRAS

X-ray substructures in clusters of galaxies provide indirect clues about the microphysical properties of the intracluster medium (ICM), which are still not very well known. In order to investigate X-ray substructures in detail, we studied archival $\sim$1~Msec Chandra data of the core of the Perseus cluster, focusing on the substructures associated with the sloshing cold front. In the east half of the cold front, we found a Kelvin-Helmholtz instability (KHI) layer candidate. The measured width-to-azimuthal extension ratio and the thermodynamic properties are all consistent with it being a KHI layer currently developing along the sloshing cold front. We found a thermal pressure deficit of the order of 10$^{-2}~\mathrm{keV~cm^{-3}}$ at the KHI layer. Assuming that turbulent pressure fully supports the pressure deficit, we estimated the turbulent strength at several hundred km~s$^{-1}$, which translates into the turbulent heating rate of $Q_\mathrm{turb}\sim 10^{-26}~\mathrm{erg~cm^{-3}~s^{-1}}$. This value agrees within an order of magnitude with the previous estimation derived from the surface brightness fluctuations, and can balance the radiative cooling at this radius. In the west half of the cold front, we found feather-like structures which are similar to the structures observed in recent numerical simulations of the gas sloshing of magnetized plasma. Their thermodynamic properties are consistent with one of the feathers being a projected gas depletion layer induced by the amplified magnetic field whose strength is $B\sim$30$~\mathrm{\mu G}$., Comment: Accepted for publication in MNRAS

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

The excitation of the filamentary gas structures surrounding giant elliptical galaxies at the center of cool-core clusters, a.k.a BCGs (brightest cluster galaxies), is key to our understanding of active galactic nucleus feedback, and of the impact of environmental and local effects on star formation. We investigate the contribution of the thermal radiation from the cooling flow surrounding BCGs to the excitation of the filaments. We explore the effects of small levels of extra-heating (turbulence), and of metallicity, on the optical and infrared lines. Using the Cloudy code, we model the photoionization and photodissociation of a slab of gas of optical depth AV{\leq}30mag at constant pressure, in order to calculate self-consistently all of the gas phases, from ionized gas to molecular gas. The ionizing source is the EUV and soft X-ray radiation emitted by the cooling gas. We test these models comparing their predictions to the rich multi-wavelength observations, from optical to submillimeter. These models reproduce most of the multi-wavelength spectra observed in the nebulae surrounding the BCGs, not only the LINER-like optical diagnostics: [O iii]{\lambda} 5007 {\AA}/H\b{eta}, [N ii]{\lambda} 6583 {\AA}/H{\alpha} and ([S ii]{\lambda} 6716 {\AA}+[S ii]{\lambda} 6731 {\AA})/H{\alpha} but also the infrared emission lines from the atomic gas. The modeled ro-vib H2 lines also match observations, which indicates that near and mid-IR H2 lines are mostly excited by collisions between H2 molecules and secondary electrons produced naturally inside the cloud by the interaction between the X-rays and the cold gas in the filament. However, there is still some tension between ionized and molecular line tracers (i.e. CO), which requires to optimize the cloud structure and the density of the molecular zone., Comment: 16 pages, 9 figures, 3 tables. Accepted for publication in A&A

KUG 1141+371 is a Seyfert 1 galaxy that shows a simultaneous flux increase in the optical and UV bands in the past decade. For instance, the latest Swift observation in 2019 shows that the UVW2 flux of the AGN in KUG 1141+371 has increased by over one order of magnitude since 2009. Meanwhile, the soft X-ray flux of KUG 1141+371 also shows a steady increase by one order of magnitude since 2007. The significant multi-wavelength luminosity change is likely due to a boost of mass accretion rate from approximately 0.6% of the Eddington limit to 3.2%, assuming a black hole mass of $10^{8}M_{\odot}$. In this work, we conduct detailed multi-epoch X-ray spectral analysis focusing on the variability of the X-ray continuum emission and the puzzling soft excess emission. In addition, our SED models also suggest a simultaneous increase of disc temperature and a decreasing inner disc radius along with the increasing accretion rate. Finally, we discuss possible connection between KUG 1141+371 and black hole transients in outburst., 18 pages, 14 figures, accepted by MNRAS

We present new deep, high-resolution, 1.5 GHz observations of the prototypical nearby Perseus galaxy cluster from the Karl G. Jansky Very Large Array. We isolate for the first time the complete tail of radio emission of the bent-jet radio galaxy NGC 1272, which had been previously mistaken to be part of the radio mini-halo. The possibility that diffuse radio galaxy emission contributes to mini-halo emission may be a general phenomenon in relaxed cool-core clusters, and should be explored. The collimated jets of NGC 1272 initially bend to the west, and then transition eastward into faint, 60 kpc-long extensions with eddy-like structures and filaments. We suggest interpretations for these structures that involve bulk motions of intracluster gas, the galaxy's orbit in the cluster including projection effects, and the passage of the galaxy through a sloshing cold front. Instabilities and turbulence created at the surface of this cold front and in the turbulent wake of the infalling host galaxy most likely play a role in the formation of the observed structures. We also discover a series of faint rings, south-east of NGC 1272, which are a type of structure that has never been seen before in galaxy clusters., 16 pages, 9 figures, Submitted to ApJ

NGC1275 is the Brightest Cluster Galaxy (BCG) in the Perseus cluster and hosts the active galactic nucleus (AGN) that is heating the central 100\,kpc of the intracluster medium (ICM) atmosphere via a regulated feedback loop. Here we use a deep 490ks Cycle-19 Chandra High-Energy Transmission Grating (HETG) observation of NGC1275 to study the anatomy of this AGN. The X-ray continuum is adequately described by an unabsorbed power-law with photon index $\Gamma\approx 1.9$, creating strong tension with the detected column of molecular gas seen via HCN and HCO$^+$ line absorption against the parsec-scale core/jet. This tension is resolved if we permit a composite X-ray source; allowing a column of $N_H\sim 8\times 10^{22}\,{\rm cm}^{-2}$ to cover $\sim 15$% of the X-ray emitter does produce a significant improvement in the statistical quality of the spectral fit. We suggest that the dominant unabsorbed component corresponds to the accretion disk corona, and the sub-dominant X-ray component is the jet working surface and/or jet cocoon that is expanding into clumpy molecular gas. We suggest that this may be a common occurence in BCG-AGN. We conduct a search for photoionized absorbers/winds and fail to detect such a component, ruling out columns and ionization parameters often seen in many other Seyfert galaxies. We detect the 6.4keV iron-K$\alpha$ fluorescence line seen previously by XMM-Newton and Hitomi. We describe an analysis methodology which combines dispersive HETG spectra, non-dispersive microcalorimeter spectra, and sensitive XMM-Newton/EPIC spectra in order to constrain (sub)arcsec-scale extensions of the iron-K$\alpha$ emission region., Comment: 13 pages, accepted for publication in MNRAS

In order to connect galaxy clusters to their progenitor protoclusters, we must constrain the star formation histories within their member galaxies and the timescale of virial collapse. In this paper we characterize the complex star-forming properties of a $z=2.5$ protocluster in the COSMOS field using ALMA dust continuum and new VLA CO(1-0) observations of two filaments associated with the structure, sometimes referred to as the "Hyperion" protocluster. We focus in particular on the protocluster "core" which has previously been suggested as the highest redshift bona fide galaxy cluster traced by extended X-ray emission in a stacked Chandra/XMM image. We re-analyze this data and refute these claims, finding that at least 40 $\pm$ 17% of extended X-ray sources of similar luminosity and size at this redshift arise instead from Inverse Compton scattering off recently extinguished radio galaxies rather than intracluster medium. Using ancillary COSMOS data, we also constrain the SEDs of the two filaments' eight constituent galaxies from the rest-frame UV to radio. We do not find evidence for enhanced star formation efficiency in the core and conclude that the constituent galaxies are already massive (M$_{\star} \approx 10^{11} M_{\odot}$), with molecular gas reservoirs $>10^{10} M_{\odot}$ that will be depleted within 200-400 Myr. Finally, we calculate the halo mass of the nested core at $z=2.5$ and conclude that it will collapse into a cluster of 2-9 $\times 10^{14} M_{\odot}$, comparable to the size of the Coma cluster at $z=0$ and accounting for at least 50% of the total estimated halo mass of the extended "Hyperion" structure., 30 pages, 12 figures, 1 appendix. Accepted for publication in ApJ

We present a recent ALMA observation of the CO(1-0) line emission in the central galaxy of the Zw 3146 galaxy cluster ($z=0.2906$). We also present updated X-ray cavity measurements from archival Chandra observations. The $5\times 10^{10}\,M_{\odot}$ supply of molecular gas, which is confined to the central 4 kpc, is marginally resolved into three extensions that are reminiscent of the filaments observed in similar systems. No velocity structure that would be indicative of ordered motion is observed. The three molecular extensions all trail X-ray cavities, and are potentially formed from the condensation of intracluster gas lifted in the wakes of the rising bubbles. Many cycles of feedback would be require to account for the entire molecular gas reservoir. The molecular gas and continuum source are mutually offset by 2.6 kpc, with no detected line emission coincident with the continuum source. It is the molecular gas, not the continuum source, that lies at the gravitational center of the brightest cluster galaxy. As the brightest cluster galaxy contains possible tidal features, the displaced continuum source may correspond to the nucleus of a merging galaxy. We also discuss the possibility that a gravitational wave recoil following a black hole merger may account for the displacement., Accepted to ApJ. 12 pages, 9 figures

The actual mechanism(s) powering galactic outflows in active galactic nuclei (AGN) is still a matter of debate. At least two physical models have been considered in the literature: wind shocks and radiation pressure on dust. Here we provide a first quantitative comparison of the AGN radiative feedback scenario with observations of galactic outflows. We directly compare our radiation pressure-driven shell models with the observational data from the most recent compilation of molecular outflows on galactic scales. We show that the observed dynamics and energetics of galactic outflows can be reproduced by AGN radiative feedback, with the inclusion of radiation trapping and/or luminosity evolution. The predicted scalings of the outflow energetics with AGN luminosity can also quantitatively account for the observational scaling relations. Furthermore, sources with both ultra-fast and molecular outflow detections are found to be located in the `forbidden' region of the $N_\mathrm{H} - \lambda$ plane. Overall, an encouraging agreement is obtained over a wide range of AGN and host galaxy parameters. We discuss our results in the context of recent observational findings and numerical simulations. In conclusion, AGN radiative feedback is a promising mechanism for driving galactic outflows that should be considered, alongside wind feedback, in the interpretation of future observational data., Comment: accepted for publication in MNRAS

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

The very small accretion disks in ultra-compact X-ray binaries (UCXBs) are special laboratories in which to study disk accretion and outflows. We report on three sets of new (250 ks total) and archival (50 ks) Chandra/HETG observations of the "dipping" neutron-star X-ray binary 4U 1916$-$053, which has an orbital period of $P\simeq 50$~minutes. We find that the bulk of the absorption in all three spectra originates in a disk atmosphere that is redshifted by $v\simeq 220-290$ $\text{km}$ $\text{s}^{-1}$, corresponding to the gravitational redshift at radius of $R \sim 1200$ $GM/{c}^{2}$. This shift is present in the strongest, most highly ionized lines (Si XIV and Fe XXVI), with a significance of 5$\sigma$. Absorption lines observed during dipping events (typically associated with the outermost disk) instead display no velocity shifts and serve as a local standard of rest, suggesting that the redshift is intrinsic to an inner disk atmosphere and not due to radial motion in the galaxy or a kick. In two spectra, there is also evidence of a more strongly redshifted component that would correspond to a disk atmosphere at $R \sim 70$ $GM/{c}^{2}$; this component is significant at the 3$\sigma$ level. Finally, in one spectrum, we find evidence of disk wind with a blue shift of $v = {-1700}^{+1700}_{-1200}$ $\text{km}$ $\text{s}^{-1}$. If real, this wind would require magnetic driving., Comment: 15 Pages, 6 Figures, Accepted to ApJ Letters

arXiv:2007.15660v1, Cosmological simulations, as well as mounting evidence from observations, have shown that supermassive black holes play a fundamental role in regulating the formation of stars throughout cosmic time. This has been clearly demonstrated in the case of galaxy clusters in which powerful feedback from the central black hole is preventing the hot intracluster gas from cooling catastrophically, thus reducing the expected star formation rates by orders of magnitude. These conclusions, however, have been almost entirely based on nearby clusters. Based on new Chandra X-ray observations, we present the first observational evidence for massive, runaway cooling occurring in the absence of supermassive black hole feedback in the high-redshift galaxy cluster SpARCS104922.6 + 564032.5 (z = 1.709). The hot intracluster gas appears to be fueling a massive burst of star formation (≈900 M⊙ yr−1) that is offset by dozens of kpc from the central galaxy. The burst is co-spatial with the coolest intracluster gas but not associated with any galaxy in the cluster. In less than 100 million years, such runaway cooling can form the same amount of stars as in the Milky Way. Therefore, intracluster stars are not only produced by tidal stripping and the disruption of cluster galaxies, but can also be produced by runaway cooling of hot intracluster gas at early times. Overall, these observations show the dramatic impact when supermassive black hole feedback fails to operate in clusters. They indicate that in the highest overdensities, such as clusters and protoclusters, runaway cooling may be a new and important mechanism for fueling massive bursts of star formation in the early universe., J.H.-L. acknowledges support from NSERC via the Discovery grant program, as well as the Canada Research Chair program. C.R. acknowledges financial support from the physics department of the Université de Montréal. G.W. acknowledges support from the National Science Foundation through grant AST-1517863, by HST program number GO15294, and by grant number 80NSSC17K0019 issued through the NASA Astrophysics Data Analysis Program (ADAP). Support for program number GO-15294 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. M.J.J. acknowledges support for the current research from the National Research Foundation of Korea under the programs 2017R1A2B2004644 and 2020R1A4A2002885. H.R.R. acknowledges support from an STFC Ernest Rutherford Fellowship and an Anne McLaren Fellowship.

We present Atacama Large Millimeter/submillimeter Array observations of the brightest cluster galaxy Hydra-A, a nearby ($z=0.054$) giant elliptical galaxy with powerful and extended radio jets. The observations reveal CO(1-0), CO(2-1), $^{13}$CO(2-1), CN(2-1), SiO(5-4), HCO$^{+}$(1-0), HCO$^{+}$(2-1), HCN(1-0), HCN(2-1), HNC(1-0) and H$_{2}$CO(3-2) absorption lines against the galaxy's bright and compact active galactic nucleus. These absorption features are due to at least 12 individual molecular clouds which lie close to the centre of the galaxy and have velocities of approximately $-50$ to $+10$ km/s relative to its recession velocity, where positive values correspond to inward motion. The absorption profiles are evidence of a clumpy interstellar medium within brightest cluster galaxies composed of clouds with similar column densities, velocity dispersions and excitation temperatures to those found at radii of several kpc in the Milky Way. We also show potential variation in a $\sim 10$ km/s wide section of the absorption profile over a two year timescale, most likely caused by relativistic motions in the hot spots of the continuum source which change the background illumination of the absorbing clouds., Comment: Accepted for publication in MNRAS

Galactic outflows are known to consist of several gas phases; however, the connection between these phases has been investigated little and only in a few objects. In this paper, we analyse Multi Unit Spectroscopic Explorer (MUSE)/Very Large Telescope (VLT) data of 26 local (U)LIRGs and study their ionized and neutral atomic phases. We also include objects from the literature to obtain a sample of 31 galaxies with spatially resolved multiphase outflow information. We find that the ionized phase of the outflows has on average an electron density three times higher than the disc (ne,disc ∼145 cm-3 versus ne,outflow ∼500 cm-3), suggesting that cloud compression in the outflow is more important than cloud dissipation. We find that the difference in extinction between outflow and disc correlates with the outflow gas mass. Together with the analysis of the outflow velocities, this suggests that at least some of the outflows are associated with the ejection of dusty clouds from the disc. This may support models where radiation pressure on dust contributes to driving galactic outflows. The presence of dust in outflows is relevant for potential formation of molecules inside them. We combine our data with millimetre data to investigate the molecular phase. We find that the molecular phase accounts for more than 60 per cent of the total mass outflow rate in most objects and this fraction is higher in active galactic nuclei (AGN)-dominated systems. The neutral atomic phase contributes of the order of 10 per cent, while the ionized phase is negligible. The ionized-to-molecular mass outflow rate declines slightly with AGN luminosity, although with a large scatter. © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society., RM and AF acknowledge ERC Advanced Grant 695671 ‘QUENCH’ and support by the Science and Technology Facilities Council (STFC). SA acknowledges support from the Spanish Ministerio de Ciencia e Innovación through grant ESP2017-83197-P. S Cazzoli acknowledges financial support from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). AM, GC, and FM acknowledge the grant PRIN 2017PH3WAT_003 from the Italian Ministry for University and Research. MP is supported by the Programa Atracción de Talento de la Comunidad de Madrid via grant 2018-T2/TIC-11715. GV acknowledges support from ANID programs FONDECYT Postdoctorado 3200802 and Basal-CATA AFB-170002. EB acknowledges the support from Comunidad de Madrid through the Atracción de Talento grant 2017-T1/TIC-5213.

We analyzed Chandra X-ray observations of five galaxy clusters whose atmospheric cooling times, entropy parameters, and cooling time to free-fall time ratios within the central galaxies lie below 1 Gyr, below 30 keV cm^2, and between 20 < tcool/tff < 50, respectively. These thermodynamic properties are commonly associated with molecular clouds, bright H-alpha emission, and star formation in central galaxies. However, none of these clusters have detectable H-alpha indicated in the ACCEPT database, nor do they have significant star formation rates or detectable molecular gas. Among these, only RBS0533 has a detectable radio/X-ray bubble which are commonly observed in cooling atmospheres. Signatures of uplifted, high metallicity atmospheric gas are absent. Despite its prominent X-ray bubble, RBS0533 lacks significant levels of molecular gas. Cold gas is absent at appreciable levels in these systems perhaps because their radio sources have failed to lift low entropy atmospheric gas to an altitude where the ratio of the cooling time to the free-fall time falls below unity., Accepted for publication in ApJ. The draft includes significant changes to the Introduction intended to better motivate this work by placing the problem in the context of current theoretical understanding of thermally unstable cooling. The abstract and conclusion were edited for clarity

We present results of temporal and spectral analyses on four XMM-Newton EPIC pn observations of IRAS 17020+4544, a narrow-line Seyfert 1 galaxy with evidence of a radio jet. Analysis of the light curves reveals that this radio-loud source does not behave like the bulk population of its radio-quiet counterparts. A trend of spectral hardening with increased flux is found. Variability is found to increase with energy, though it decreases as the spectrum hardens. The first 40 ks of the most recent observation behave uniquely among the epochs, exhibiting a softer spectral state than at any other time. Possible non-stationarity at low energies is found, with no such effect present at higher energies, suggesting at least two distinct spectral components. A reverberation signature is confirmed, with the lag-frequency, lag-energy, and covariance spectra changing significantly during the soft-state epoch. The temporal analysis suggests a variable power-law in the presence of a reflection component, thus motivating such a fit for the 0.3-10 keV EPIC pn spectra from all epochs. We find an acceptable spectral fit using the timing-motivated parameters and report the detection of a broad Fe K emission line, requiring an additional model component beyond the reflection spectrum. We discuss links between this source and other narrow-line Seyfert 1 sources that show evidence of jet activity, finding similarities among this currently very limited sample of interesting objects., Comment: Accepted for publication in MNRAS. 19 pages, 14 figures

Axions/axion-like particles (ALPs) are a well motivated extension of the Standard Model and are generic within String Theory. The X-ray transparency of the intracluster medium (ICM) in galaxy clusters is a powerful probe of light ALPs (with mass $, Comment: Published in The Astrophysical Journal, 2020, vol 890, pp59. This posting corrects typos in equation (2) and the likelihood function just prior to equation (3). Typos were introduced into the draft at late stage and the analysis is correct

A variety of large-scale diffuse radio structures have been identified in many clusters with the advent of new state-of-the-art facilities in radio astronomy. Among these diffuse radio structures, radio mini-halos are found in the central regions of cool core clusters. Their origin is still unknown and they are challenging to discover; less than thirty have been published to date. Based on new VLA observations, we confirmed the mini-halo in the massive strong cool core cluster PKS 0745$-$191 ($z=0.1028$) and discovered one in the massive cool core cluster MACS J1447.4+0827 ($z=0.3755$). Furthermore, using a detailed analysis of all known mini-halos, we explore the relation between mini-halos and AGN feedback processes from the central galaxy. We find evidence of strong, previously unknown correlations between mini-halo radio power and X-ray cavity power, and between mini-halo and the central galaxy radio power related to the relativistic jets when spectrally decomposing the AGN radio emission into a component for past outbursts and one for on-going accretion. Overall, our study indicates that mini-halos are directly connected to the central AGN in clusters, following previous suppositions. We hypothesize that AGN feedback may be one of the dominant mechanisms giving rise to mini-halos by injecting energy into the intra-cluster medium and reaccelerating an old population of particles, while sloshing motion may drive the overall shape of mini-halos inside cold fronts. AGN feedback may therefore not only play a vital role in offsetting cooling in cool core clusters, but may also play a fundamental role in re-energizing non-thermal particles in clusters., Comment: 26 pages, 9 figures, 8 tables, accepted for publication in MNRAS

We present the results of X-ray spectral and timing analyses of the closest gamma-ray emitting narrow-line Seyfert 1 ($\gamma$-NLS1) galaxy, 1H 0323+342. We use observations from a recent, simultaneous XMM-Newton/NuSTAR campaign. As in radio-quiet NLS1s, the spectrum reveals a soft excess at low energies ($\lesssim2$ keV) and reflection features such as a broad iron K emission line. We also find evidence of a hard excess at energies above $\sim35$ keV that is likely a consequence of jet emission. Our analysis shows that relativistic reflection is statistically required, and using a combination of models that includes the reflection model relxill for the broadband spectrum, we find an inclination of $i=63^{+7}_{-5}$ degrees, which is in tension with much lower values inferred by superluminal motion in radio observations. We also find a flat ($q=2.2\pm0.3$) emissivity profile, implying that there is more reflected flux than usual being emitted from the outer regions of the disk, which in turn suggests a deviation from the thin disk model assumption. We discuss possible reasons for this, such as reflection off of a thick accretion disk geometry., Comment: Accepted for publication in MNRAS. 11 pages, 9 figures; references added

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

We present a detailed analysis of the spectral properties of the Seyfert 1 galaxy 1H0419-577, based on the archival XMM-Newton, NuSTAR and simultaneous Swift observations taken between 2002-2015. All the observations show a broad emission line feature at the iron band. We demonstrate that the broad band spectral variability at different levels can be explained by the combination of light-bending effects in the vicinity of the central black hole plus a thin warm absorber. We obtain a black hole spin of a > 0.98 by fitting the multi-epoch spectra with the relativistic disc reflection model. 1H0419-577 is accreting at 40% of its Eddington limit and its X-ray band shows the hardest powerlaw continuum in the highest flux state, which was previously more commonly seen in AGNs with a low accretion rate (e.g. $L_{\rm X} /L_{\rm Edd} < 10^{-2}$). The NuSTAR observation shows a cool coronal temperature of $kT=30^{+22}_{-7}$keV in the high flux state., Accepted by MNRAS

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

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

Recent observations confirm the existence of ultra-massive black holes (UMBH) in the nuclei of compact galaxies, with physical properties similar to NGC 1277. The nature of these objects poses a new puzzle to the `black hole-host galaxy co-evolution' scenario. We discuss the potential link between UMBH and galaxy compactness, possibly connected via extreme active galactic nucleus (AGN) feedback at early times ($z > 2$). In our picture, AGN feedback is driven by radiation pressure on dust. We suggest that early UMBH feedback blows away all the gas beyond a $\sim$kpc or so, while triggering star formation at inner radii, eventually leaving a compact galaxy remnant. Such extreme UMBH feedback can also affect the surrounding environment on larger scales, e.g. the outflowing stars may form a diffuse stellar halo around the compact galaxy, or even escape into the intergalactic or intracluster medium. On the other hand, less massive black holes will drive less powerful feedback, such that the stars formed within the AGN feedback-driven outflow remain bound to the host galaxy, and contribute to its size growth over cosmic time., accepted for publication in MNRAS

Active galactic nucleus (AGN) feedback is the process by which supermassive black holes in the centres of galaxies may moderate the growth of their hosts. Gas outflows from supermassive black holes release huge quantities of energy into the interstellar medium, clearing the surrounding gas. The most extreme of these, the ultra-fast outflows (UFOs), are the subset of X-ray detected outflows with velocities higher than 10,000 km/s, believed to originate in relativistic disc winds, a few hundred gravitational radii from the black hole. The absorption features produced by these outflows are variable, but no clear link has been found between the behaviour of the X-ray continuum and the energy or equivalent width of the outflow features due to the long time-scales of quasar variability. Here, we present the detection of multiple absorption lines from an extreme ultra-fast gas flow in the X-ray spectrum of the active galactic nucleus IRAS 13224-3809, at 0.236+/-0.006 times the speed of light (71,000 km/s), where the absorption is strongly anti-correlated with the emission from the inner regions of the accretion disk. If the gas flow is identified as a genuine outflow then it is in the fastest 5 per cent of such winds, and its variability is hundreds of times faster than in other variable winds, allowing us to observe in hours what would take months in a quasar. We find signatures of the wind simultaneously in both low and high energy detectors, which are consistent with a single ionized outflow, linking the two phenomena. The detection of the wind responding to the emission from the inner disk demonstrates a connection between accretion processes occurring on very different scales, with the X-rays from within a few gravitational radii of the black hole ionizing the relativistically outflowing gas as the flux rises., Comment: 13 pages, 7 figures, published in Nature 02/03/17

We present a high density disc reflection spectral analysis of a sample of 17 Seyfert 1 galaxies to study the inner disc densities at different black hole mass scales and accretion rates. All the available XMM-Newton observations in the archive are used. OM observations in the optical/UV band are used to estimate their accretion rates. We find that 65% of sources in our sample show a disc density significantly higher than 1e15 cm^{-3}, which was assumed in previous reflection-based spectral analyses. The best-fit disc densities show an anti-correlation with black hole mass and mass accretion rate. High density disc reflection model can successfully explain the soft excess emission and significantly reduce inferred iron abundances. We also compare our black hole spin and disc inclination angle measurements with previous analyses., Accepted by MNRAS. The first paper of this series can be found here: arXiv:1901.01739

We explore the impact of the central black hole (BH) spin on the large-scale properties of the host galaxy, by considering radiative feedback. The BH spin determines the radiation pattern from the accretion disc, which directly imprints on the geometry of the radiation-driven outflows. We show that for low BH spins, the emission is vertically focused, giving rise to polar/prolate outflows; while for high BH spins, the radiation pattern is more isotropic, leading to quasi-spherical/oblate outflows. Reversing the argument, we can potentially deduce the spin of the central BH from the observed morphology of galactic outflows. In principle, this may provide a novel way of constraining the central BH spin from galaxy-scale observations. Indeed, the BH spin can have significant macroscopic effects on galactic scales, ultimately shaping the large-scale feedback and the resulting obscuration., accepted for publication in MNRAS

We study the X-ray properties of two elliptical galaxies, NGC 1270 and NGC 1272, in the core of the Perseus cluster with deep Chandra observations. Both galaxies have central supermassive black holes, the mass of which is $6.0 \times 10^{9}$ M$_{\odot}$ and $2.0 \times 10^{9}$ M$_{\odot}$ respectively. Our aim is to examine relatively cool soft X-ray emitting gas within the central region of these massive early-type galaxies. Such gas, referred to as a Minicorona in previous studies is common in the core of large elliptical cluster galaxies. It has not been completely stripped or evaporated by the surrounding hot intracluster medium and nor fully accreted onto the central black hole. With thermal emission from the minicorona dominating over any power-law radiation components, we find that both NGC 1270 and NGC 1272 encompass minicoronae, the temperature and radius of which are $0.99$ keV and $0.63$ keV; $1.4$ kpc and $1.2$ kpc respectively. For NGC 1272, the thermal coronal component dominates the core emission by a factor of over 10. We show that the depletion time scale of minicoronal gas via viscous stripping is shorter by a factor of $100$ than the replenishment time scale due to stellar mass loss. Magnetic fields are presumably responsible for suppression of the transport processes. Finally, we show that both objects have to meet a balance between cooling and heating as well as that among mass replenishment, stripping and accretion., Accepted for publication in MNRAS; 9 pages, 4 figures, 2 tables

We present new, deep (245 ks) Chandra observations of the galaxy cluster Abell 1664 ($z = 0.1283$). These images reveal rich structure, including elongation and accompanying compressions of the X-ray isophotes in the NE-SW direction, suggesting that the hot gas is sloshing in the gravitational potential. This sloshing has resulted in cold fronts, at distances of 55, 115 and 320 kpc from the cluster center. Our results indicate that the core of A1664 is highly disturbed, as the global metallicity and cooling time flatten at small radii, implying mixing on large scales. The central AGN appears to have recently undergone a mechanical outburst, as evidenced by our detection of cavities. These cavities are the X-ray manifestations of radio bubbles inflated by the AGN, and may explain the motion of cold molecular CO clouds previously observed with ALMA. The estimated mechanical power of the AGN, using the minimum energy required to inflate the cavities as a proxy, is $P_{\rm cav} = (1.1 \pm 1.0) \times 10^{44} $ erg s$^{-1}$, which may be enough to drive the molecular gas flows, and offset the cooling luminosity of the ICM, at $L_{\rm cool} = (1.90 \pm0.01)\times 10^{44}$ erg s$^{-1}$. This mechanical power is orders of magnitude higher than the measured upper limit on the X-ray luminosity of the central AGN, suggesting that its black hole may be extremely massive and/or radiatively inefficient. We map temperature variations on the same spatial scale as the molecular gas, and find that the most rapidly cooling gas is mostly coincident with the molecular gas reservoir centered on the BCG's systemic velocity observed with ALMA and may be fueling cold accretion onto the central black hole., Submitted to ApJ. 14 pages, 7 figures, 1 table, 1 appendix. Comments welcome!

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

We present the analysis of the first Nuclear Spectroscopic Telescope Array observations (~220 ks), simultaneous with the last Suzaku observations (~50 ks), of the active galactic nucleus of the bright Seyfert 1 galaxy Mrk 509. The time-averaged spectrum in the 1–79 keV X-ray band is dominated by a power-law continuum (Γ ~ 1.8–1.9), a strong soft excess around 1 keV, and signatures of X-ray reflection in the form of Fe K emission (~6.4 keV), an Fe K absorption edge (~7.1 keV), and a Compton hump due to electron scattering (~20–30 keV). We show that these data can be described by two very different prescriptions for the soft excess: a warm (kT ~ 0.5–1 keV) and optically thick (τ ~ 10–20) Comptonizing corona or a relativistically blurred ionized reflection spectrum from the inner regions of the accretion disk. While these two scenarios cannot be distinguished based on their fit statistics, we argue that the parameters required by the warm corona model are physically incompatible with the conditions of standard coronae. Detailed photoionization calculations show that even in the most favorable conditions, the warm corona should produce strong absorption in the observed spectrum. On the other hand, while the relativistic reflection model provides a satisfactory description of the data, it also requires extreme parameters, such as maximum black hole spin, a very low and compact hot corona, and a very high density for the inner accretion disk. Deeper observations of this source are thus necessary to confirm the presence of relativistic reflection and further understand the nature of its soft excess.

We present recent {\it Chandra} X-ray observations of the RXJ0821.0+0752 galaxy cluster in addition to ALMA observations of the CO(1-0) and CO(3-2) line emission tracing the molecular gas in its central galaxy. All of the CO line emission, originating from a $10^{10}\,M_{\odot}$ molecular gas reservoir, is located several kpc away from the nucleus of the central galaxy. The cold gas is concentrated into two main clumps surrounded by a diffuse envelope. They form a wide filament coincident with a plume of bright X-ray emission emanating from the cluster core. This plume encompasses a putative X-ray cavity that is only large enough to have uplifted a few percent of the molecular gas. Unlike other brightest cluster galaxies, stimulated cooling, where X-ray cavities lift low entropy cluster gas until it becomes thermally unstable, cannot have produced the observed gas reservoir. Instead, the molecular gas has likely formed as a result of sloshing motions in the intracluster medium induced by a nearby galaxy. Sloshing can emulate uplift by dislodging gas from the galactic center. This gas has the shortest cooling time, so will condense if disrupted for long enough., 10 pages, 5 figures, accepted to ApJ

We present the results of a detailed multi-wavelength study of a sample of sixteen narrow-line Seyfert 1 (NLSy1) galaxies known in $\gamma$-rays so far. This includes a focused X-ray spectral analysis, to compare them with a more general NLSy1 population, and a broadband spectral energy distribution (SED) modeling considering the leptonic radiative processes to understand their similarity/dissimilarity with blazars. The X-ray spectra of $\gamma$-NLSy1 galaxies exhibit similarities both with typical NLSy1 sources below $\lesssim$2 keV and blazars at higher energies. We also find weak evidences of excess absorption in the soft X-ray spectra of 3 sources and a tentative detection of Fe line in 1H~0323+342. A comparison of the broadband parameters derived from the SED modeling reveals the similarity of $\gamma$-NLSy1 objects with blazars, in particular more with flat spectrum radio quasars. The $\gamma$-NLS1 galaxies host relatively low power jets with small bulk Lorentz factors with respect to blazars and this explains the paucity of such sources in the $\gamma$-ray catalogs and identification of an even fewer parent population members. Many of the observed features of these intriguing objects suggest they host low-mass black holes. The accretion rate in Eddington units can be considered as the driving factor to explain the physical properties of $\gamma$-NLSy1 sources, similar to that which is known for general blazar population., Comment: 34 pages, 11 figures, 8 tables, to appear in the Astrophysical journal

We present XMM-Newton, NuSTAR, Swift and Hubble Space Telescope observations of the Narrow-line Seyfert 1 galaxy Mrk 335 in a protracted low state in 2018 and 2019. The X-ray flux is at the lowest level so far observed, and the extremely low continuum flux reveals a host of soft X-ray emission lines from photoionised gas. The simultaneous UV flux drop suggests that the variability is intrinsic to the source, and we confirm this with broad-band X-ray spectroscopy. The dominance of the soft X-ray lines at low energies and distant reflection at high energies is therefore due to the respective emission regions being located far enough from the X-ray source that they have not yet seen the flux drop. Between the two XMM-Newton spectra, taken 6 months apart, the emission line ratio in the Ovii triplet changes drastically. We attribute this change to a drop in the ionisation of intervening warm absorption, which means that the absorber must cover a large fraction of the line emitting region, and extend much further from the black hole than previously assumed. The HST spectrum, taken in 2018, shows that new absorption features have appeared on the blue wings of Ciii*, Ly{\alpha}, Nv, Siiv and Civ, likely due to absorbing gas cooling in response to the low flux state., Comment: 15 pages, 11 figures, accepted for publication in MNRAS

We study molecular outflows in a sample of 45 local galaxies, both star forming and active galactic nucleus (AGN), primarily by using CO data from the Atacama Large Millimeter/submillimeter Array (ALMA) archive and from the literature. For a subsample, we also compare the molecular outflow with the ionized and neutral atomic phases. We infer an empirical analytical function relating the outflow rate simultaneously to the star formation rate (SFR), L AGN, and galaxy stellar mass; this relation is much tighter than the relations with the individual quantities. The outflow kinetic power shows a larger scatter than in previous, more biased studies, spanning from 0.1 to 5 per cent of L AGN, while the momentum rate ranges from 1 to 30 times L AGN /c, indicating that these outflows can be both energy driven, but with a broad range of coupling efficiencies with the interstellar medium (ISM), and radiation pressure driven. For about 10 per cent of the objects, the outflow energetics significantly exceed the maximum theoretical values; we interpret these as 'fossil outflows' resulting from activity of a past strong AGN, which has now faded. We estimate that, in the stellar mass range probed here (> 10 10 ,M⊙), less than 5 per cent of the outflowing gas escapes the galaxy. The molecular gas depletion time associated with the outflow can be as short as a few million years in powerful AGN; however, the total gas (H 2 + Hi) depletion times are much longer. Altogether, our findings suggest that even AGN-driven outflows might be relatively ineffective in clearing galaxies of their entire gas content, although they are likely capable of clearing and quenching the central region. We study molecular outflows in a sample of 45 local galaxies, both star forming and active galactic nucleus (AGN), primarily by using CO data from the Atacama Large Millimeter/submillimeter Array (ALMA) archive and from the literature. For a subsample, we also compare the molecular outflow with the ionized and neutral atomic phases. We infer an empirical analytical function relating the outflow rate simultaneously to the star formation rate (SFR), L AGN, and galaxy stellar mass; this relation is much tighter than the relations with the individual quantities. The outflow kinetic power shows a larger scatter than in previous, more biased studies, spanning from 0.1 to 5 per cent of L AGN, while the momentum rate ranges from 1 to 30 times L AGN /c, indicating that these outflows can be both energy driven, but with a broad range of coupling efficiencies with the interstellar medium (ISM), and radiation pressure driven. For about 10 per cent of the objects, the outflow energetics significantly exceed the maximum theoretical values; we interpret these as 'fossil outflows' resulting from activity of a past strong AGN, which has now faded. We estimate that, in the stellar mass range probed here (> 1010,M⊙), less than 5 per cent of the outflowing gas escapes the galaxy. The molecular gas depletion time associated with the outflow can be as short as a few million years in powerful AGN; however, the total gas (H2 + Hi) depletion times are much longer. Altogether, our findings suggest that even AGN-driven outflows might be relatively ineffective in clearing galaxies of their entire gas content, although they are likely capable of clearing and quenching the central region.

We present an analysis of new and archival ALMA observations of molecular gas in twelve central cluster galaxies. We examine emerging trends in molecular filament morphology and gas velocities to understand their origins. Molecular gas masses in these systems span $10^9-10^{11}\mathrm{M}_{\odot}$, far more than most gas-rich galaxies. ALMA images reveal a distribution of morphologies from filamentary to disk-dominated structures. Circumnuclear disks on kiloparsec scales appear rare. In most systems, half to nearly all of the molecular gas lies in filamentary structures with masses of a few $\times10^{8-10}\mathrm{M}_{\odot}$ that extend radially several to several tens of kpc. In nearly all cases the molecular gas velocities lie far below stellar velocity dispersions, indicating youth, transience or both. Filament bulk velocities lie far below the galaxy's escape and free-fall speeds indicating they are bound and being decelerated. Most extended molecular filaments surround or lie beneath radio bubbles inflated by the central AGN. Smooth velocity gradients found along the filaments are consistent with gas flowing along streamlines surrounding these bubbles. Evidence suggests most of the molecular clouds formed from low entropy X-ray gas that became thermally unstable and cooled when lifted by the buoyant bubbles. Uplifted gas will stall and fall back to the galaxy in a circulating flow. The distribution in morphologies from filament to disk-dominated sources therefore implies slowly evolving molecular structures driven by the episodic activity of the AGN., 20 pages, 21 figures, 4 tables, accepted to MNRAS

We present the discovery of diffuse optical line emission in the Centaurus cluster seen with the MUSE IFU. The unparalleled sensitivity of MUSE allows us to detect the faint emission from these structures which extend well beyond the bounds of the previously known filaments. Diffuse structures (emission surrounding the filaments, a northern shell and an extended Halo) are detected in many lines typical of the nebulae in cluster cores ([NII]$_{\lambda 6548\&6583}$ ,[SII]$_{\lambda 6716\&6731}$, [OI]$_{\lambda 6300}$, [OIII]$_{\lambda 4959\&5007}$ etc.) but are more than an order of magnitude fainter than the filaments, with the faint halo only detected through the brightest line in the spectrum ([NII]$_{\lambda 6583}$). These structures are shown to be kinematically distinct from the stars in the central galaxy and have different physical and excitation states to the filaments. Possible origins are discussed for each structure in turn and we conclude that shocks and/or pressure imbalances are resulting in gas dispersed throughout the cluster core, formed from either disrupted filaments or direct cooling, which is not confined to the bright filaments., Comment: 17 pages, 19 figures, Published in MNRAS

We report the discovery of RX J2317.8-4422 in an extremely low X-ray flux state by the Neil Gehrels Swift observatory in 2014 April/May. In total, the low-energy X-ray emission dropped by a factor 100. We have carried out multi-wavelength follow-up observations of this Narrow-Line Seyfert 1 galaxy. Here we present observations with Swift, XMM-Newton, and NuSTAR in October and November 2014 and further monitoring observations by Swift from 2015 to 2018. Compared with the beginning of the Swift observations in 2005, in the November 2014 XMM and NuSTAR observation RX J2317--4422.8 dropped by a factor of about 80 in the 0.3-10 keV band. While the high-state Swift observations can be interpreted by a partial covering absorption model with a moderate absorption column density of $N_H=5.4\times 10^{22}$ cm$^{-2}$ or blurred reflection, due to dominating background at energies above 2 keV the low-state XMM data can not distinguish between different multi-component models and were adequately fit with a single power-law model. We discuss various scenarios like a long-term change of the accretion rate or absorption as the cause for the strong variability seen in RX J2317.8--4422., Comment: 10 pages, 7 figures, accepted to be published in the Monthly Notices of the Royal Astronomical Society

Multi-phase filamentary structures around Brightest Cluster Galaxies are likely a key step of AGN-feedback. We observed molecular gas in 3 cool cluster cores: Centaurus, Abell S1101, and RXJ1539.5 and gathered ALMA and MUSE data for 12 other clusters. Those observations show clumpy, massive and long, 3--25 kpc, molecular filaments, preferentially located around the radio bubbles inflated by the AGN (Active Galactic Nucleus). Two objects show nuclear molecular disks. The optical nebula is certainly tracing the warm envelopes of cold molecular filaments. Surprisingly, the radial profile of the H$\alpha$/CO flux ratio is roughly constant for most of the objects, suggesting that (i) between 1.2 to 7 times more cold gas could be present and (ii) local processes must be responsible for the excitation. Projected velocities are between 100--400 km s$^{-1}$, with disturbed kinematics and sometimes coherent gradients. This is likely due to the mixing in projection of several thin unresolved filaments. The velocity fields may be stirred by turbulence induced by bubbles, jets or merger-induced sloshing. Velocity and dispersions are low, below the escape velocity. Cold clouds should eventually fall back and fuel the AGN. We compare the filament's radial extent, r$_{fil}$, with the region where the X-ray gas can become thermally unstable. The filaments are always inside the low-entropy and short cooling time region, where t$_{cool}$/t$_{ff}$, Comment: 33 Pages, 17 Figures, submitted to A&A

We present a spectral analysis of cool and cooling gas in 45 cool-core clusters and groups of galaxies obtained from Reflection Grating Spectrometer (RGS) XMM-$Newton$ observations. The high-resolution spectra show FeXVII emission in many clusters, which implies the existence of cooling flows. The cooling rates are measured between the bulk Intracluster Medium (ICM) temperature and 0.01 keV and are typically weak, operating at less than a few tens of $\rm M_{\odot}\rm yr^{-1}$ in clusters, and less than 1 $\rm M_{\odot}\rm yr^{-1}$ in groups of galaxies. They are 10-30% of the classical cooling rates in the absence of heating, which suggests that AGN feedback has a high level of efficiency. If cooling flows terminate at 0.7 keV in clusters, the associated cooling rates are higher, and have a typical value of a few to a few tens of $\rm M_{\odot}\rm yr^{-1}$. Since the soft X-ray emitting region, where the temperature $kT, Comment: 17 pages, 10 figures, accepted for publication in MNRAS

A triggered 140 ks XMM-Newton observation of the narrow-line Seyfert 1 (NLS1) Mrk 335 in December 2015 caught the active galaxy at its lowest X-ray flux since 2007. The NLS1 is relatively quiescent for the first ~120 ks of the observation before it flares in brightness by a factor of about five in the last 20 ks. Although only part of the flare is captured before the observation is terminated, the data reveal significant differences between the flare and quiescent phases. During the low-flux state, Mrk 335 demonstrates a reflection-dominated spectrum that results from a compact corona around a Kerr black hole. In addition to the rapid brightening, the flare is further described by spectral softening and a falling reflection fraction that are consistent with previous observations advocating at least part of the corona in Mrk 335 could be the base of an aborted jet. The spectrum during the flaring interval reveals several residuals between the 2-3 sigma level that could be attributed to absorption lines from a highly ionised plasma that is moving outward at v~0.12c. It could be that the increased luminosity during the flare enhances the radiation pressure sufficiently to launch a possible wind. If the wind is indeed responding to the change in corona luminosity then it must be located within ~80 Rg. The escape velocity at this distance is comparable to the estimated wind velocity. If confirmed, this is the first example of a radio-quiet AGN exhibiting behaviour consistent with both diffuse and collimated outflow., Comment: 11 pages, 10 figures, accepted for publication in MNRAS

Hyper-luminous infrared galaxies (HyLIRGs) lie at the extreme luminosity end of the IR galaxy population with $L_{\rm IR}>10^{13}$L$_\odot$. They are thought to be closer counterparts of the more distant sub-mm galaxies, and should therefore be optimal targets to study the most massive systems in formation. We present deep $Chandra$ observations of IRAS~F15307+3252 (100ks), a classical HyLIRG located at $z=$0.93 and hosting a radio-loud AGN ($L_{\rm 1.4 GHz}\sim3.5\times10^{25}$ W/Hz). The $Chandra$ images reveal the presence of extended ($r=160$ kpc), asymmetric X-ray emission in the soft 0.3-2.0 keV band that has no radio counterpart. We therefore argue that the emission is of thermal origin originating from a hot intragroup or intracluster medium virializing in the potential. We find that the temperature ($\sim2$ keV) and bolometric X-ray luminosity ($\sim3\times10^{43}$ erg s$^{-1}$) of the gas follow the expected $L_{\rm X-ray}-T$ correlation for groups and clusters, and that the gas has a remarkably short cooling time of $1.2$ Gyrs. In addition, VLA radio observations reveal that the galaxy hosts an unresolved compact steep-spectrum (CSS) source, most likely indicating the presence of a young radio source similar to 3C186. We also confirm that the nucleus is dominated by a redshifted 6.4 keV Fe K$\alpha$ line, strongly suggesting that the AGN is Compton-thick. Finally, Hubble images reveal an over-density of galaxies and sub-structure in the galaxy that correlates with soft X-ray emission. This could be a snapshot view of on-going groupings expected in a growing cluster environment. IRAS~F15307+3252 might therefore be a rare example of a group in the process of transforming into a cluster., Comment: 12 pages, 7 figures, 4 tables. Accepted for publication in MNRAS (11 August 2016)

EK thanks Ari Laor for interesting discussions on this work and acknowledges support from the International Space Science Institute. This work is based on observations obtained with XMM–Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. EK thanks the Gates Cambridge Scholarship and the Hubble Fellowship Program. Support for Program number HSTHF2-51360.001-A was provided by NASA through a Hubble Fellowship grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. EK, WNA, and ACF acknowledge support from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312789, StrongGravity. CSR acknowledges support from NASA under grant NNX14AF86G. EMC gratefully acknowledges support from the National Science Foundation through CAREER award number 1351222.

Quasi-periodic oscillations (QPOs) are coherent peaks of variability power observed in the X-ray power spectra (PSDs) of stellar mass X-ray binaries (XRBs). A scale invariance of the accretion process implies they should be present in the active galactic nuclei. The first robust detection was a ∼ 1 h periodicity in the Seyfert galaxy RE J1034+396 from a ∼ 90 ks XMM-Newton observation; however, subsequent observations failed to detect the QPO in the 0.3–10.0 keV band. In this talk we present the recent detection of the ∼ 1 h periodicity in the 1.0–4.0 keV band of 4 further low-flux/spectrally-harder observations of RE J1034+396 (see Alston et al. 2014). We also present recent work on the discovery of a QPO in the Seyfert galaxy, MS 2254.9–3712, which again is only detected in energy bands associated with the primary power-law continuum emission (Alston et al. 2015). We conclude these features are most likely analogous to the high-frequency QPOs observed in XRBs. In both sources, we also see evidence for X-ray reverberation at the QPO frequency, where soft X-ray bands and Iron Kα emission lag the primary X-ray continuum. These time delays may provide another diagnostic for understanding the underlying QPO mechanism observed in accreting black holes. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Significant reservoirs of cool gas are observed in the circumgalactic medium (CGM) surrounding galaxies. The CGM is also found to contain substantial amounts of metals and dust, which require some transport mechanism. We consider AGN (active galactic nucleus) feedback-driven outflows based on radiation pressure on dust. Dusty gas is ejected when the central luminosity exceeds the effective Eddington luminosity for dust. We obtain that a higher dust-to-gas ratio leads to a lower critical luminosity, implying that the more dusty gas is more easily expelled. Dusty outflows can reach large radii with a range of velocities (depending on the outflowing shell configuration and the ambient density distribution) and may account for the observed CGM gas. In our picture, dust is required in order to drive AGN feedback, and the preferential expulsion of dusty gas in the outflows may naturally explain the presence of dust in the CGM. On the other hand, the most powerful AGN outflow events can potentially drive gas out of the local galaxy group. We further discuss the effects of radiation pressure of the central AGN on satellite galaxies. AGN radiative feedback may therefore have a significant impact on the evolution of the whole surrounding environment., Monthly Notices of the Royal Astronomical Society, 457 (3), ISSN:0035-8711, ISSN:1365-2966, ISSN:1365-8711

We report on Chandra gratings spectra of the stellar-mass black hole GRS 1915+105 obtained during a novel, highly obscured state. As the source entered this state, a dense, massive accretion disk wind was detected through strong absorption lines. Photionization modeling indicates that it must originate close to the central engine, orders of magnitude from the outer accretion disk. Strong, nearly sinusoidal flux variability in this phase yielded a key insight: the wind is blue-shifted when its column density is relatively low, but red-shifted as it approaches the Compton-thick threshold. At no point does the wind appear to achieve the local escape velocity; in this sense, it is a "failed wind." Later observations suggest that the disk ultimately fails to keep even the central engine clear of gas, leading to heavily obscured and Compton-thick states characterized by very strong Fe K emission lines. Indeed, these later spectra are successfully described using models developed for obscured AGN. We discuss our results in terms the remarkable similarity of GRS 1915+105 deep in its "obscured state" to Seyfert-2 and Compton-thick AGN, and explore how our understanding of accretion and obscuration in massive black holes is impacted by our observations., Submitted to ApJ

We report the discovery of a $\sim 1.5 \times 10^{-4}$ Hz ($\sim 2$ hr) X-ray quasi-periodic oscillation (QPO) in the active galaxy MS 2254.9-3712, using a $\sim 70$ ks XMM-Newton observation. The QPO is significantly detected ($\sim 3.3 \sigma$) in the $1.2 - 5.0$ keV band only, connecting its origin with the primary X-ray power-law continuum. We detect a highly coherent soft lag between the $0.3 - 0.7$ keV and $1.2 - 5.0$ keV energy bands at the QPO frequency and at a frequency band in a 3:2 ratio, strongly suggesting the presence of a QPO harmonic. An iron K$\alpha$ reverberation lag is found at the harmonic frequency, indicating the reflecting material subtends some angle to the primary continuum, which is modulated by the QPO mechanism. Frequency resolved spectroscopy reveals the QPO and harmonic to have a hard energy dependence. These properties of the QPO variability, together with the current black hole mass estimate, $M_{\rm bh} \sim 4 \times 10^{6} M_{\rm sun}$, are consistent with the QPO originating from the same process as the high frequency QPO phenomenon observed in black hole X-ray binaries. Principle component analysis reveals the spectral variability in MS 2254.9-3712 is similar to that of the active galaxy RE J1034+396, a source which also displays an X-ray QPO. This suggests a distinct spectral variability pattern for accreting black holes when in a state where QPOs are present., Comment: Accepted by MNRAS following moderate revision. 10 pages, 10 figures, 1 table. Comments welcomed

著者人数: 39名（所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): Simionescu, Aurora), Accepted: 2018-07-28, 資料番号: SA1180203000