74 results on '"Risaliti A"'
Search Results
2. Disentangling the complex broad-band X-ray spectrum of IRAS 13197−1627 with NuSTAR, XMM–Newton and Suzaku
- Author
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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.
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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
3. Bulk Comptonization: new hints from the luminous blazar 4C+25.05
- Author
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E. S. Kammoun, Gabriele Ghisellini, Annalisa Celotti, Emanuele Nardini, E. Behar, Guido Risaliti, ITA, and USA
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Astrophysics::High Energy Astrophysical Phenomena ,galaxies: active ,FOS: Physical sciences ,Context (language use) ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,X-rays: general ,01 natural sciences ,Power law ,quasars: general ,quasars: individual: 4C+25.05 ,X-rays: galaxies ,Spectral line ,symbols.namesake ,Settore FIS/05 - Astronomia e Astrofisica ,0103 physical sciences ,Black-body radiation ,Blazar ,010303 astronomy & astrophysics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,010308 nuclear & particles physics ,Astronomy ,Astronomy and Astrophysics ,Quasar ,Rest frame ,Lorentz factor ,Space and Planetary Science ,symbols ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
Blazars are often characterized by a spectral break at soft X-rays, whose origin is still debated. While most sources show a flattening, some exhibit a blackbody-like soft excess with temperatures of the order of $\sim$0.1 keV, similar to low-luminosity, non-jetted Seyferts. Here we present the analysis of the simultaneous XMM-Newton and NuSTAR observation of the luminous FSRQ 4C+25.05 ($z=2.368$). The observed 0.3-30 keV spectrum is best described by the sum of a hard X-ray power law ($\Gamma = 1.38_{-0.03}^{+0.05}$) and a soft component, approximated by a blackbody with $kT_{\rm BB} = 0.66_{-0.04}^{+0.05}$ keV (rest frame). If the spectrum of 4C+25.05 is interpreted in the context of bulk Comptonization by cold electrons of broad-line region photons emitted in the direction of the jet, such an unusual temperature implies a bulk Lorentz factor of the jet of $\Gamma_{\rm bulk}\sim 11.7$. Bulk Comptonization is expected to be ubiquitous on physical grounds, yet no clear signature of it has been found so far, possibly due to its transient nature and the lack of high-quality, broad-band X-ray spectra., Comment: 6 pages, 4 figures, 2 tables. Accepted for publication in MNRASL
- Published
- 2017
4. Q wind code release: a non-hydrodynamical approach to modelling line-driven winds in active galactic nuclei
- Author
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Quera-Bofarull, Arnau, primary, Done, Chris, primary, Lacey, Cedric, primary, McDowell, Jonathan C, primary, Risaliti, Guido, primary, and Elvis, Martin, primary
- Published
- 2020
- Full Text
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5. Orientation effects on spectral emission features of quasars
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Guido Risaliti, Alessandro Marconi, Susanna Bisogni, and ITA
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Physics ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Quasar ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Lambda ,Astrophysics - Astrophysics of Galaxies ,01 natural sciences ,Spectral line ,Orientation (vector space) ,Spectral emission ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Emission spectrum ,010303 astronomy & astrophysics ,Equivalent width ,Astrophysics::Galaxy Astrophysics ,Line (formation) - Abstract
We present an analysis of the orientation effects in Sloan Digital Sky Survey (SDSS) quasar composite spectra. In a previous work, we have shown that the equivalent width (EW) of the [O III] λ5007 Å (vacuum rest wavelength 5008.24 Å) line is a reliable indicator of the inclination of the accretion disc. Here, we have selected a sample of ∼12 000 quasars from the SDSS 7th Data Release and divided it in subsamples with different values of EW_{[{O {III}]}}. We find inclination effects both on broad and narrow quasars emission lines, among which an increasing broadening from low to high EW for the broad lines and a decreasing importance of the blue component for the narrow lines. These effects are naturally explained with a variation of source inclination from nearly face-on to edge-on, confirming the goodness of EW_{[{O {III}]}} as an orientation indicator. Moreover, we suggest that orientation effects could explain, at least partially, the origin of the anticorrelation between [O III] and Fe II intensities, I.e. the well-known eigenvector 1.
- Published
- 2016
6. Simultaneous NuSTAR and XMM–Newton 0.5–80舁keV spectroscopy of the narrow-line Seyfert 1 galaxy SWIFT J2127.4+5654
- Author
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Giorgio Matt, Fiona A. Harrison, Guido Risaliti, A. C. Fabian, Christopher S. Reynolds, Laura Brenneman, Finn Erland Christensen, Massimo Cappi, Franz E. Bauer, Wenqi Zhang, F. Fuerst, Dominic J. Walton, S. E. Boggs, Giovanni Miniutti, William W. Craig, Andrea Marinucci, Patricia Arevalo, David R. Ballantyne, Erin Kara, Daniel Stern, C. J. Hailey, Martin Elvis, Mislav Baloković, Marinucci, A., Matt, Giorgio, Kara, E., Miniutti, G., Elvis, M., Arevalo, P., Ballantyne, D. R., Balokovic, M., Bauer, F., Brenneman, L., Boggs, S. E., Cappi, M., Christensen, F. E., Craig, W. W., Fabian, A. C., Fuerst, F., Hailey, C. J., Harrison, F. A., Risaliti, G., Reynolds, C. S., Stern, D. K., Walton, D. J., and Zhang, W.
- Subjects
High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,X-ray astronomy ,Active galactic nucleus ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,01 natural sciences ,Accretion (astrophysics) ,Galaxy ,Spectral line ,Black hole ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Emission spectrum ,Astrophysics - High Energy Astrophysical Phenomena ,Spectroscopy ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present a broad band spectral analysis of the joint XMM-Newton and NuSTAR observational campaign of the Narrow Line Seyfert 1 SWIFT J2127.4+5654, consisting of 300 ks performed during three XMM-Newton orbits. We detect a relativistic broadened iron K$\alpha$ line originating from the innermost regions of the accretion disc surrounding the central black hole, from which we infer an intermediate spin of $a$=$0.58^{+0.11}_{-0.17}$. The intrinsic spectrum is steep ($\Gamma=2.08\pm0.01$) as commonly found in Narrow Line Seyfert 1 galaxies, while the cutoff energy (E$_{\rm c}=108^{+11}_{-10}$ keV) falls within the range observed in Broad Line Seyfert 1 Galaxies. We measure a low-frequency lag that increases steadily with energy, while at high frequencies, there is a clear lag following the shape of the broad Fe K emission line. Interestingly, the observed Fe K lag in SWIFT J2127.4+5654 is not as broad as in other sources that have maximally spinning black holes. The lag amplitude suggests a continuum-to-reprocessor distance of about $ 10-20\ r_{\mathrm{g}}$. These timing results independently support an intermediate black hole spin and a compact corona., Comment: 11 pages, 10 figures, accepted for publication on MNRAS
- Published
- 2014
7. Orientation effects on the near-infrared broad-band emission of quasars
- Author
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Bisogni, Susanna, primary, Lusso, Elisabeta, additional, Marconi, Alessandro, additional, and Risaliti, Guido, additional
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- 2019
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8. A low-flux state in IRAS 00521−7054 seen withNuSTARandXMM–Newton: relativistic reflection and an ultrafast outflow
- Author
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Walton, D J, primary, Nardini, E, additional, Gallo, L C, additional, Reynolds, M T, additional, Ricci, C, additional, Dauser, T, additional, Fabian, A C, additional, García, J A, additional, Harrison, F A, additional, Risaliti, G, additional, and Stern, D, additional
- Published
- 2019
- Full Text
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9. Search for X-ray occultations in active galactic nuclei
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M. Salvati, Paola Pietrini, Guido Risaliti, and G. Torricelli-Ciamponi
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High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,X-ray ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Light curve ,Astrophysics - Astrophysics of Galaxies ,Occultation ,Space and Planetary Science ,Homogeneous ,Primary (astronomy) ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics - High Energy Astrophysical Phenomena ,Absorption (electromagnetic radiation) ,Astrophysics::Galaxy Astrophysics ,Line (formation) - Abstract
Recent time-resolved spectral studies of a few Active Galactic Nuclei in hard X-rays revealed occultations of the X-ray primary source probably by Broad Line Region (BLR) clouds. An important open question on the structure of the circumnuclear medium of AGN is whether this phenomenon is common, i.e. whether a significant fraction of the X-ray absorption in AGN is due to BLR clouds. Here we present the first attempt to perform this kind of analysis in a homogeneous way, on a statistically representative sample of AGN, consisting of the ~40 brightest sources with long XMM-Newton and/or Suzaku observations. We describe our method, based on a simple analysis of hardness-ratio light curves, and its validation through a complete spectroscopic analysis of a few cases. We find that X-ray eclipses, most probably due to clouds at the distance of the BLR, are common in sources where the expected occultation time is compatible with the observation time, while they are not found in sources with longer estimated occultation times. Overall, our results show that occultations by BLR clouds may be responsible for most of the observed X-ray spectral variability at energies higher than 2 keV, on time scales longer than a few ks., Comment: Accepted for publication in MNRAS. 15 pages, 7 figures. Table 2 not included, will be available in the published version. Please contact the authors if you need it in advance of publication
- Published
- 2014
10. PCA of PCA: principal component analysis of partial covering absorption in NGC 1365
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Michael Parker, Guido Risaliti, Dominic J. Walton, and A. C. Fabian
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High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Spectral line ,Space and Planetary Science ,Principal component analysis ,Reflection (physics) ,Astrophysics - High Energy Astrophysical Phenomena ,Absorption (electromagnetic radiation) - Abstract
We analyse 400 ks of XMM-Newton data on the active galactic nucleus NGC 1365 using principal component analysis (PCA) to identify model independent spectral components. We find two significant components and demonstrate that they are qualitatively different from those found in MCG?6-30-15 using the same method. As the variability in NGC 1365 is known to be due to changes in the parameters of a partial covering neutral absorber, this shows that the same mechanism cannot be the driver of variability in MCG-6-30-15. By examining intervals where the spectrum shows relatively low absorption we separate the effects of intrinsic source variability, including signatures of relativistic reflection, from variations in the intervening absorption. We simulate the principal components produced by different physical variations, and show that PCA provides a clear distinction between absorption and reflection as the drivers of variability in AGN spectra. The simulations are shown to reproduce the PCA spectra of both NGC 1365 and MCG-6-30-15, and further demonstrate that the dominant cause of spectral variability in these two sources requires a qualitatively different mechanism., 8 pages, 10 figures. Accepted for publication in MNRAS
- Published
- 2014
11. SP769THE ROLE OF CYP3A5 GENOTYPE AND TACROLIMUS MONITORING IN STABLE KIDNEY TRANSPLANTATIONS
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Gian Luigi Adani, Umberto Baccarani, Andrea Risaliti, Clotilde Vallone, Massimo Baraldo, P. Tulissi, Domenico Montanaro, Elda Righi, and Giuseppe Damante
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Transplantation ,medicine.medical_specialty ,Kidney ,business.industry ,Gastroenterology ,Tacrolimus ,medicine.anatomical_structure ,Nephrology ,Internal medicine ,Genotype ,medicine ,Social role ,business ,CYP3A5 - Published
- 2018
12. Spectral and polarimetric signatures of X-ray eclipses in AGNs
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Kammoun, E S, primary, Marin, F, additional, Dovčiak, M, additional, Nardini, E, additional, Risaliti, G, additional, and Sanfrutos, M, additional
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- 2018
- Full Text
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13. SP769THE ROLE OF CYP3A5 GENOTYPE AND TACROLIMUS MONITORING IN STABLE KIDNEY TRANSPLANTATIONS
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Baraldo, Massimo, primary, Adani, Gian Luigi, additional, Righi, Elda, additional, Tulissi, Patrizia, additional, Vallone, Clotilde, additional, Baccarani, Umberto, additional, Damante, Giuseppe, additional, Risaliti, Andrea, additional, and Montanaro, Domenico, additional
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- 2018
- Full Text
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14. Disentangling the complex broad-band X-ray spectrum of IRAS 13197−1627 with NuSTAR, XMM–Newton and Suzaku
- Author
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Walton, D. J., primary, Brightman, M., additional, Risaliti, G., additional, Fabian, A. C., additional, Fürst, F., additional, Harrison, F. A., additional, Lohfink, A., additional, Matt, G., additional, Miniutti, G., additional, Parker, M. L., additional, and Stern, D., additional
- Published
- 2017
- Full Text
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15. Bulk Comptonization: new hints from the luminous blazar 4C+25.05
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Kammoun, E S, primary, Nardini, E, additional, Risaliti, G, additional, Ghisellini, G, additional, Behar, E, additional, and Celotti, A, additional
- Published
- 2017
- Full Text
- View/download PDF
16. Decoupling absorption and continuum variability in the Seyfert 2 NGC 4507
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Guido Risaliti, V. Braito, James Reeves, Lucía Ballo, Andy Ptak, and T. J. Turner
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High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Photon ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Torus ,Astrophysics ,Galaxy ,Full width at half maximum ,Space and Planetary Science ,Reprocessor ,Ionization ,Emission spectrum ,Astrophysics - High Energy Astrophysical Phenomena ,Equivalent width - Abstract
We present the results of the Suzaku observation of the Seyfert 2 galaxy NGC 4507. This source is one of the X-ray brightest Compton-thin Seyfert 2s and a candidate for a variable absorber. Suzaku caught NGC 4507 in a highly absorbed state characterised by a high column density (NH \sim8 x10^23 cm^-2), a strong reflected component (R\sim 1.9) and a high equivalent width Fe K alpha emission line (EW\sim 500 eV). The Fe K alpha emission line is unresolved at the resolution of the Suzaku CCDs (sigma < 30 eV or FWHM < 3000 km s^-1) and most likely originates in a distant absorber. The Fe K beta emission line is also clearly detected and its intensity is marginally higher than the theoretical value for low ionisation Fe. A comparison with previous observations performed with XMM-Newton and BeppoSAX reveals that the X-ray spectral curvature changes on a timescale of a few months. We analysed all these historical observations, with standard models as well as with a most recent model for a toroidal reprocessor and found that the main driver of the observed 2-10 keV spectral variability is a change of the line-of-sight obscuration, varying from \sim4x10^23 cm^-2 to \sim9 x 10^23 cm^-2. The primary continuum is also variable, although its photon index does not appear to vary, while the Fe K alpha line and reflection component are consistent with being constant across the observations. This suggests the presence of a rather constant reprocessor and that the observed line of sight NH variability is either due to a certain degree of clumpiness of the putative torus or due to the presence of a second clumpy absorber., 14 pages, 7 figures, 5 tables. Accepted for publication in MNRAS
- Published
- 2012
17. The X-ray reflector in NGC 4945: a time- and space-resolved portrait
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Emanuele Nardini, Andrea Marinucci, Giorgio Matt, Junfeng Wang, Guido Risaliti, Martin Elvis, Giuseppina Fabbiano, and Simone Bianchi
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Physics ,Spacetime ,Astrophysics::High Energy Astrophysical Phenomena ,media_common.quotation_subject ,X-ray ,Astronomy and Astrophysics ,Reflector (antenna) ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Physical structure ,Space and Planetary Science ,Sky ,Primary (astronomy) ,Reflection (physics) ,Absorption (electromagnetic radiation) ,Astrophysics::Galaxy Astrophysics ,media_common - Abstract
We present a time, spectral and imaging analysis of the X-ray reflector in NGC 4945, which reveals its geometrical and physical structure with unprecedented detail. NGC 4945 hosts one of the brightest AGN in the sky above 10 keV, but it is only visible through its reflected/scattered emission below 10 keV, due to absorption by a column density of ~4\times10^24 cm-2. A new Suzaku campaign of 5 observations spanning ~6 months, together with past XMM-Newton and Chandra observations, show a remarkable constancy (within 30-50 pc, well within the imaging capabilities of Chandra at the distance of NGC 4945 (1"~18 pc). Accordingly, the Chandra imaging reveals a resolved, flattened, ~150 pc-long clumpy structure, whose spectrum is fully due to cold reflection of the primary AGN emission. The clumpiness may explain the small covering factor derived from the spectral and variability properties.
- Published
- 2012
18. Suzaku X-ray spectral study of the Compton-thick Seyfert galaxy NGC 5135
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Valentina Braito, Guido Risaliti, Veeresh Singh, and Prajval Shastri
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Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Continuum (design consultancy) ,X-ray ,Astronomy and Astrophysics ,Torus ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Viewing angle ,Galaxy ,Luminosity ,Space and Planetary Science ,Reflection (physics) ,Emission spectrum ,Astrophysics::Galaxy Astrophysics - Abstract
We present the 0.5 - 50 keV Suzaku broad-band X-ray spectral study of the Compton-thick AGN in NGC 5135. The Suzaku observation provides the first detection of NGC 5135 above 10 keV that allowed us, for the first time, to estimate the absorbing column density, the intrinsic X-ray luminosity, the strength of the reflection component and the viewing angle of the torus for this AGN. The 0.5 - 10 keV spectrum of NGC 5135 is characterized by the standard components for a Compton-thick source: a scattered continuum, a prominent Fe K{\alpha} emission line (EW ~ 2.1 keV) and a soft excess. At higher energies (E > 10 keV) the intrinsic AGN continuum shows up, implying an absorbing column density of the order of ~ 2.5 \times 10^24 cm^-2 and the intrinsic 2.0 - 10 keV X-ray luminosity of ~ 1.8 \times 10^43 erg s^-1. Assuming a toroidal geometry of the reprocessing material we show that an edge-on view of the obscuring torus is preferred in this source.
- Published
- 2011
19. Probing general relativistic effects during active galactic nuclei X-ray eclipses
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Laura Brenneman, M. Salvati, E. Nardini, Guido Risaliti, and Martin Elvis
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Physics ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Thin disc ,symbols.namesake ,Accretion disc ,Space and Planetary Science ,symbols ,Astrophysics::Earth and Planetary Astrophysics ,Relativistic quantum chemistry ,Doppler effect ,Event (particle physics) ,Astrophysics::Galaxy Astrophysics ,Gravitational redshift ,Eclipse - Abstract
Long X-ray observations of bright active galactic nuclei (AGN) show that X-ray eclipses, with durations from a few hours to a few days, are rather common. This opens up a new window of opportunity in the search for signatures of relativistic effects in AGN: an obscuring cloud covers/uncovers different parts of the accretion disc at different times, allowing a direct check of the expected pattern of disc emission. In particular, the combination of gravitational redshift and relativistic Doppler boosting should imply strong differences between the receding and approaching parts of an inclined thin disc. At present, these effects may be already detectable with a ‘lucky’XMM–Newton or Suzaku observation of a complete eclipse by a Compton-thick cloud (a rare, but not impossible-to-see event). In the future, higher sensitivity observatories will be able to perform these tests easily on tens of AGN. This will provide a powerful and direct way to test extreme gravity, and to probe the structure of AGN in the close vicinity of the central black holes.
- Published
- 2011
20. The effects of X-ray absorption variability in NGC 4395
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Guido Risaliti and Emanuele Nardini
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Physics ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,Continuum (design consultancy) ,Flux ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Power law ,Galaxy ,Black hole ,Space and Planetary Science ,Spectral slope ,Absorption (electromagnetic radiation) ,Astrophysics::Galaxy Astrophysics - Abstract
We present a new X-ray analysis of the dwarf Seyfert galaxy NGC 4395, based on two archival XMM-Newton and Suzaku observations. This source is well known for a series of remarkable properties: one of the smallest estimated black hole masses among Active Galactic Nuclei (of the order of ~10^5 M_sun), intense flux variability on very short time-scales (a few tens of seconds), an unusually flat X-ray continuum (Gamma ~ 1.4 over the 2-10 keV energy range). NGC 4395 is also characterized by significant variations of the X-ray spectral shape, and here we show that such behaviour can be explained through the partial occultation by circumnuclear cold absorbers with column densities of ~10^22-10^23 cm^-2. In this scenario, the primary X-ray emission is best reproduced by means of a power law with a standard Gamma ~ 1.8 photon index, consistent with both the spectral slope observed at higher energies and the values typical of local AGN.
- Published
- 2011
21. Compton-thick active galactic nuclei inside local ultraluminous infrared galaxies
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E. Nardini and Guido Risaliti
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Luminous infrared galaxy ,Physics ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,Strong interaction ,Flux ,Astronomy and Astrophysics ,Quasar ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Spectral line ,Luminosity ,Space and Planetary Science ,Absorption (electromagnetic radiation) ,Astrophysics::Galaxy Astrophysics - Abstract
We present the X-ray analysis of the most luminous obscured active galactic nuclei (AGN) inside local ultraluminous infrared galaxies (ULIRGs). Our sample consists of ten sources, harbouring AGN components with estimated luminosity in excess of ~10^12 L_sun and yet unidentified at optical wavelengths because of their large obscuration. According to the Chandra and XMM-Newton spectra, only in two cases out of ten clear AGN signatures are detected at 2-10 keV in the shape of reflected emission. The X-ray flux from the starburst (SB) components, instead, is always broadly consistent with the expectations based on their IR emission. The most convincing explanation for the missing AGN detections is therefore the Compton-thickness of the X-ray absorber. In general, the combination of our mid-IR and X-ray spectral analysis suggests that the environment surrounding the AGN component in ULIRGs is much richer in gas and dust than in ordinary active galaxies, and the degree of AGN absorption can be tentatively related to the SB intensity, indicating a strong interaction between the two processes and supporting the ULIRG/quasar evolutionary scheme.
- Published
- 2011
22. The Spitzer/IRAC view of black hole-bulge scaling relations
- Author
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Alessandro Marconi, Guido Risaliti, Leslie K. Hunt, and E. Sani
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Physics ,Effective radius ,Supermassive black hole ,Stellar mass ,Sigma ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy ,Luminosity ,Black hole ,Space and Planetary Science ,Bulge ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present a mid-IR investigation of the scaling relations between supermassive black hole masses (MBH) and the structural parameters of the host spheroids in local galaxies. The work is based on two-dimensional bulge-disk decompositions of Spitzer/IRAC 3.6 um images of 57 galaxies with MBH estimates. Our estimates of effective radii (Re) and surface brightnesses, combined with velocity dispersions (sigma) from the literature, define a FP relation consistent with previous determinations but doubling the observed range in Re. None of our galaxies is an outlier of the FP, demonstrating the accuracy of our bulge-disk decomposition which also allows us to independently identify pseudobulges in our sample. We calibrate M/L at 3.6 um by using the tight Mdyn-Lbul relation (~0.1 dex of rms) and find that no color corrections are required to estimate the stellar mass. The 3.6 um luminosity is thus the best tracer of Mstar yet studied. We then explore the connection between MBH and bulge structural parameters (luminosity, mass, effective radius). We find tight correlations of MBH with both 3.6 um bulge luminosity and dynamical mass (MBH/Mdyn~1/1000), with rms of ~0.35 dex, similar to the MBH-sigma relation. Our results are consistent with previous determinations at shorter wavelengths. By using our calibrated M/L, we rescale MBH-Lbul to obtain the MBH-Mstar relation, which can be used as the local reference for high-z studies which probe the cosmic evolution of MBH-galaxy relations and where the stellar mass is inferred directly from luminosity measurements. The analysis of pseudobulges shows that 4 out of 9 lie on the scaling relations within the observed scatter, while those with small MBH are significantly displaced. We explore the different origins for such behavior, while considering the possibility of nuclear morphological components not reproduced by our two-dimensional decomposition.
- Published
- 2011
23. [O iii] equivalent width and orientation effects in quasars
- Author
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M. Salvati, Guido Risaliti, and Alessandro Marconi
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Physics ,Line-of-sight ,Astrophysics::High Energy Astrophysical Phenomena ,Continuum (design consultancy) ,Doubly ionized oxygen ,Astronomy and Astrophysics ,Quasar ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Luminosity ,Space and Planetary Science ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Emission spectrum ,Equivalent width ,Astrophysics::Galaxy Astrophysics ,Line (formation) - Abstract
The flux of the [OIII] line is considered to be a good indicator of the bolometric emission of quasars. The observed continuum emission from the accretion disc should instead be strongly dependent on the inclination angle theta between the disc axis and the line of sight. Based on this, the equivalent width (EW) of [OIII] should provide a direct measure of theta. Here we analyze the distribution of EW([OIII]) in a sample of ~6,000 SDSS quasars, and find that it can be accurately reproduced assuming a relatively small intrinsic scatter and a random distribution of inclination angles. This result has several implications: 1) it is a direct proof of the disc-like emission of the optical continuum of quasars; 2) the value of EW([OIII]) can be used as a proxy of the inclination, to correct the measured continuum emission and then estimate the bolometric luminosity of quasars; 3) the presence of almost edge-on discs among broad line quasars implies that the accretion disc is not aligned with the circumnuclear absorber, and/or that the covering fraction of the latter is rather small. Finally, we show that a similar analysis of EW distributions of broad lines (Hbeta, Mg II, C IV) provides no evidence of inclination effects, suggesting a disc-like geometry of the broad emission line region.
- Published
- 2010
24. Enhanced star formation in narrow-line Seyfert 1 active galactic nuclei revealed bySpitzer
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E. Sani, Guido Risaliti, Luigi C. Gallo, Benny Trakhtenbrot, Eckhard Sturm, Thomas Boller, Dieter Lutz, and Hagai Netzer
- Subjects
Physics ,Space and Planetary Science ,Star formation ,Astrophysics::High Energy Astrophysical Phenomena ,Low resolution ,ROSAT ,Astrophysics::Solar and Stellar Astrophysics ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Spectroscopy ,Astrophysics::Galaxy Astrophysics ,Galaxy - Abstract
We present new low resolution Spitzer mid-infrared spectroscopy of a sample of 20 ROSAT selected local Narrow Line Seyfert 1 galaxies (NLS1s). We detect strong AGN continuum in all and clear PAH emission in 70% of the sources. The 6.2 micron PAH luminosity spans three orders of magnitudes, from ~10^(39) erg/s to ~10^(42) erg/s providing strong evidence for intense ongoing star formation in the circumnuclear regions of these sources. Using the IRS/Spitzer archive we gather a large number of additional NLS1s and their broad line counterparts (BLS1s) and constructed NLS1 and BLS1 sub-samples to compare them in various ways. The comparison shows a clear separation according to FWHM(H_beta) such that objects with narrower broad H_beta lines are the strongest PAH emitters. We test this division in various ways trying to remove biases due to luminosity and aperture size. Specifically, we find that star formation activity around NLS1 AGN is larger than around BLS1 of the same AGN luminosity. The above result seems to hold over the entire range of distance and luminosity. Moreover the star formation rate is higher in low black hole mass and high L/L_Edd systems indicating that black hole growth and star formation are occurring simultaneously.
- Published
- 2010
25. A quantitative determination of the AGN content in local ULIRGs throughL-band spectroscopy
- Author
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Guido Risaliti, E. Sani, and Masatoshi Imanishi
- Subjects
Physics ,L band ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Infrared ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Quantitative determination ,Luminosity ,Space and Planetary Science ,Content (measure theory) ,Spectroscopy ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present a quantitative estimate of the relative AGN/starburst content in a sample of 59 nearby (z85% of the observed infrared luminosity. The subsample of sources optically classified as LINERs (31 objects) shows a similar AGN/starburst distribution as the whole sample, indicating a composite nature for this class of objects. We also show that a few ULIRGs, optically classified as starbursts, have L-band spectral features suggesting the presence of a buried AGN., 8 Pages, 5 figures. Accepted for publication in MNRAS
- Published
- 2010
26. Exploring the active galactic nucleus and starburst content of local ultraluminous infrared galaxies through 5-8 μm spectroscopy
- Author
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Guido Risaliti, Y. Watabe, E. Sani, E. Nardini, M. Salvati, Roberto Maiolino, and A. Marconi
- Subjects
Luminous infrared galaxy ,Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Active galactic nucleus ,Star formation ,Infrared ,Astrophysics::High Energy Astrophysical Phenomena ,Bolometer ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Redshift ,Spectral line ,law.invention ,Space and Planetary Science ,law ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Spectroscopy ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present a 5-8 micron analysis of the Spitzer-IRS spectra of 71 ultraluminous infrared galaxies (ULIRGs) with redshift z < 0.15, devoted to the study of the role of active galactic nuclei (AGN) and starbursts (SB) as the power source of the extreme infrared emission. Around 5 micron an AGN is much brighter (by a factor 30) than a starburst of equal bolometric luminosity. This allows us to detect the presence of even faint accretion-driven cores inside ULIRGs: signatures of AGN activity are found in 70 per cent of our sample (50/71 sources). Through a simple analytical model we are also able to obtain a quantitative estimate of the AGN/SB contribution to the overall energy output of each source. Although the main fraction of ULIRG luminosity is confirmed to arise from star formation events, the AGN contribution is non-negligible (23 per cent) and is shown to increase with luminosity. The existence of a rather heterogeneous pattern in the composition and geometrical structure of the dust among ULIRGs is newly supported by the comparison between individual absorption features and continuum extinction., 56 pages, 13 figures, 4 tables. Accepted for publication in MNRAS
- Published
- 2009
27. The active galactic nuclei/starburst content in high-redshift ultraluminous infrared galaxies
- Author
-
M. Salvati, Guido Risaliti, E. Nardini, E. Sani, A. Marconi, and Y. Watabe
- Subjects
Physics ,Active galactic nucleus ,Infrared ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Spectral line ,Redshift ,Luminosity ,Space and Planetary Science ,Content (measure theory) ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We apply a simple model, tested on local ULIRGs, to disentangle the active galactic nucleus (AGN) and starburst contributions in submillimiter and 24um-selected ULIRGs observed with the Spitzer-IRS spectrometer. We quantitatively estimate the average AGN contribution to the stacked 6-8um rest-frame spectra of these sources in different luminosity and redshift ranges, and, under the assumption of similar infrared-to-bolometric ratios as in local ULIRGs, the relative AGN/starburst contributions to the total infrared luminosity. Though the starburst component is always dominant in submillimeter-selected ULIRGs, we find a significant increase of the AGN contribution at redshift z>2.3 with respect to lower z objects. Finally, we quantitatively confirm that the mid-infrared emission of 24um-selected ULIRGs is dominated by the AGN component, but the starburst component contributes significantly to the bolometric luminosity.
- Published
- 2009
28. Spectral decomposition of starbursts and active galactic nuclei in 5–8 μm Spitzer-IRS spectra of local ultraluminous infrared galaxies
- Author
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E. Nardini, G. Risaliti, M. Salvati, E. Sani, M. Imanishi, A. Marconi, and R. Maiolino
- Subjects
Luminous infrared galaxy ,Physics ,Active galactic nucleus ,Star formation ,Infrared ,Astrophysics::High Energy Astrophysical Phenomena ,Analytic model ,Dominant power ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Spectral line ,Luminosity ,Space and Planetary Science ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present an analysis of the 5-8 micron Spitzer-IRS spectra of a sample of 68 local Ultraluminous Infrared Galaxies (ULIRGs). Our diagnostic technique allows a clear separation of the active galactic nucleus (AGN) and starburst (SB) components in the observed mid-IR emission, and a simple analytic model provides a quantitative estimate of the AGN/starburst contribution to the bolometric luminosity. We show that AGNs are ~30 times brighter at 6 micron than starbursts with the same bolometric luminosity, so that even faint AGNs can be detected. Star formation events are confirmed as the dominant power source for extreme infrared activity, since ~85% of ULIRG luminosity arises from the SB component. Nonetheless an AGN is present in the majority (46/68) of our sources.
- Published
- 2008
29. Spatially resolved Fe K spectroscopy of NGC 4945
- Author
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Marinucci, A., primary, Bianchi, S., additional, Fabbiano, G., additional, Matt, G., additional, Risaliti, G., additional, Nardini, E., additional, and Wang, J., additional
- Published
- 2017
- Full Text
- View/download PDF
30. New flaring of an ultraluminous X-ray source in NGC 1365
- Author
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Andreas Zezas, Alessandro Baldi, A. R. King, Guido Risaliti, Roberto Soria, Giuseppina Fabbiano, and V. La Parola
- Subjects
Physics ,Ultraluminous X-ray source ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Flux ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Radius ,Galaxy ,Luminosity ,Black hole ,Corona (optical phenomenon) ,symbols.namesake ,Space and Planetary Science ,Eddington luminosity ,symbols ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We have studied a highly variable ultraluminous X-ray source (ULX) in the Fornax galaxy NGC 1365, with a series of 12 Chandra and XMM-Newton observations between 2002 and 2006. In 2006 April, the source peaked at a luminosity ~ 3 x 10^{40} erg/s in the 0.3-10 keV band (similar to the maximum luminosity found by ASCA in 1995), and declined on an e-folding timescale ~ 3 days. The X-ray spectrum is always dominated by a broad power-law-like component. When the source is seen at X-ray luminosities ~ 10^{40} erg/s, an additional soft thermal component (which we interpret as emission from the accretion disk) contributes ~ 1/4 of the X-ray flux; when the luminosity is higher, ~ 3 x 10^{40} erg/s, the thermal component is not detected and must contribute < 10% of the flux. At the beginning of the decline, ionized absorption is detected around 0.5-2 keV; it is a possible signature of a massive outflow. The power-law is always hard, with a photon index Gamma ~ 1.7 (and even flatter at times), as is generally the case with bright ULXs. We speculate that this source and perhaps most other bright ULXs are in a high/hard state: as the accretion rate increases well above the Eddington limit, more and more power is extracted from the inner region of the inflow through non-radiative channels, and is used to power a Comptonizing corona, jet or wind. The observed thermal component comes from the standard outer disk; the transition radius between outer standard disk and Comptonizing inner region moves further out and to lower disk temperatures as the accretion rate increases. This produces the observed appearance of a large, cool disk. Based on X-ray luminosity and spectral arguments, we suggest that this accreting black hole has a likely mass ~ 50-150 Msun (even without accounting for possible beaming)., 14 pages, to appear in MNRAS
- Published
- 2007
31. RapidNHchanges in NGC 4151
- Author
-
Fabrizio Fiore, G. C. Perola, Fabrizio Nicastro, Simonetta Puccetti, Guido Risaliti, M. Capalbi, and M. Elvis
- Subjects
Physics ,Line-of-sight ,Astrophysics::High Energy Astrophysical Phenomena ,Flux ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy ,Space and Planetary Science ,Ionization ,Reverberation mapping ,Emission spectrum ,Absorption (electromagnetic radiation) ,Schwarzschild radius - Abstract
We have analyzed the two longest (elapsed time > 3 days) BeppoSAX observations of the X-ray brightest Seyfert galaxy, NGC 4151, to search for spectral variability on time-scales from a few tens of ksec to years. We found in both cases highly significant spectral variability below ~ 6 keV down to the shortest time-scales investigated. These variations can be naturally explained in terms of variations in the low energy cut-off due to obscuring matter along the line of sight. If the cut-off is modeled by two neutral absorption components, one fully covering the source and the second covering only a fraction of the source, the shortest time-scale of variability of a few days constrains the location of the obscuring matter to within 3.4 X 10^4 Schwarzschild radii from the central X-ray source. This is consistent with the distance of the Broad Emission Line Region, as inferred from reverberation mapping, and difficult to reconcile with the parsec scale dusty molecular torus of Krolik & Begelman (1988). We have also explored a more complex absorption structure, namely the presence of an ionized absorber. Although the behaviour of the ionization parameter is nicely consistent with the expectations, the results are not completely satisfactory from the statistical point of view. The overall absorption during the 2001 December observation is lower than in all other historical observations with similar 2-10 keV flux. This suggests that absorption variability plays a crucial role in the observed flux variability of this source.
- Published
- 2007
32. Coronal properties of the luminous radio-quiet quasar QSO B2202–209
- Author
-
Kammoun, E. S., primary, Risaliti, G., additional, Stern, D., additional, Jun, H. D., additional, Graham, M., additional, Celotti, A., additional, Behar, E., additional, Elvis, M., additional, Harrison, F. A., additional, Matt, G., additional, and Walton, D. J., additional
- Published
- 2016
- Full Text
- View/download PDF
33. Local supermassive black holes, relics of active galactic nuclei and the X-ray background
- Author
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Roberto Maiolino, Alessandro Marconi, Roberto Gilli, Guido Risaliti, M. Salvati, and L. K. Hunt
- Subjects
Physics ,Supermassive black hole ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics (astro-ph) ,X-ray background ,FOS: Physical sciences ,Velocity dispersion ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy ,Accretion (astrophysics) ,Continuity equation ,Space and Planetary Science ,Bulge ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We quantify the importance of mass accretion during AGN phases in the growth of supermassive black holes (BH) by comparing the mass function of black holes in the local universe with that expected from AGN relics, which are black holes grown entirely with mass accretion during AGN phases. The local BH mass function (BHMF) is estimated by applying the well-known correlations between BH mass, bulge luminosity and stellar velocity dispersion to galaxy luminosity and velocity functions. The density of BH's in the local universe is 4.6 (-1.4; +1.9) (h/0.7)^2 10^5 Msun Mpc^-3. The relic BHMF is derived from the continuity equation with the only assumption that AGN activity is due to accretion onto massive BH's and that merging is not important. We find that the relic BHMF at z=0 is generated mainly at z 10^9 Msun. (abridged), 19 pages, 18 figures, MNRAS in press, minor changes following referee's comments
- Published
- 2004
34. Orientation effects on spectral emission features of quasars
- Author
-
Bisogni, Susanna, primary, Marconi, Alessandro, additional, and Risaliti, Guido, additional
- Published
- 2016
- Full Text
- View/download PDF
35. The nature of the torus in the heavily obscured AGN Markarian 3: an X-ray study
- Author
-
Guainazzi, M., primary, Risaliti, G., additional, Awaki, H., additional, Arevalo, P., additional, Bauer, F. E., additional, Bianchi, S., additional, Boggs, S. E., additional, Brandt, W. N., additional, Brightman, M., additional, Christensen, F. E., additional, Craig, W. W., additional, Forster, K., additional, Hailey, C. J., additional, Harrison, F., additional, Koss, M., additional, Longinotti, A., additional, Markwardt, C., additional, Marinucci, A., additional, Matt, G., additional, Reynolds, C. S., additional, Ricci, C., additional, Stern, D., additional, Svoboda, J., additional, Walton, D., additional, and Zhang, W., additional
- Published
- 2016
- Full Text
- View/download PDF
36. TheChandra/HETG view of NGC 1365 in a Compton-thick state
- Author
-
Nardini, E., primary, Gofford, J., additional, Reeves, J. N., additional, Braito, V., additional, Risaliti, G., additional, and Costa, M., additional
- Published
- 2015
- Full Text
- View/download PDF
37. Final verdict from XMM-Newton: the X-ray obscured Seyfert galaxy NGC 5506 has a broad Fe Kα line
- Author
-
Stefano Bianchi, Julien Malzac, Guido Risaliti, Matteo Guainazzi, Mauro Dadina, Jelle Kaastra, and Giorgio Matt
- Subjects
Physics ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,X-ray ,Astronomy and Astrophysics ,Torus ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy ,Space and Planetary Science ,Observatory ,Emissivity ,Astrophysics::Solar and Stellar Astrophysics ,Emission spectrum ,Basso continuo ,Astrophysics::Galaxy Astrophysics - Abstract
We present the first unambiguous evidence of a broad (Gaussian width ∼330 eV) component of the iron K α fluorescent emission line in the X-ray obscured narrow-line Seyfert 1 galaxy, NGC 5506. This is the main result of a spectroscopic monitoring campaign on this source, performed with the XMM–Newton observatory between 2001 February and 2009 January. The broad line lacks extreme redward skewness. If modelled with a relativistic component, the profile of the line is consistent with a flat emissivity radial dependence (α � 1.9). The disc inclination (� 40 ◦ ) is nominally larger than typically observed in unobscured active galactic nuclei (AGNs), in agreement with most measurements of broadened iron lines in Seyfert 2 galaxies. The quality of the data allows us to decompose the full iron emission-line complex, and to study its long-term (time-scales of weeks to yr) variability pattern. The intensity of the neutral and narrow iron Kα core remains constant during the monitoring campaign. This indicates that the optically thick gas responsible for the non-relativistic reprocessing of the primary AGN continuum in NGC 5506 is probably located in the torus rather than in the optical broad-line region.
- Published
- 2010
38. SP848A SHARED PROTOCOL FOR CARDIOVASCULAR EVALUATION SIGNIFICANTLY REDUCES THE TIME FOR WAITLISTING THE POTENTIAL KIDNEY TRANSPLANT RECIPIENTS
- Author
-
Montanaro, Domenico, primary, Groppuzo, Maria, additional, Vallone, Clotilde, additional, Tulissi, Patrizia, additional, Adani, Gian Luigi, additional, Risaliti, Andrea, additional, Mioni, Roberto, additional, Miani, Daniela, additional, and Costa, Maria Gabriella, additional
- Published
- 2015
- Full Text
- View/download PDF
39. Revealing the X-ray variability of AGN with principal component analysis
- Author
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Parker, M. L., primary, Fabian, A. C., additional, Matt, G., additional, Koljonen, K. I. I., additional, Kara, E., additional, Alston, W., additional, Walton, D. J., additional, Marinucci, A., additional, Brenneman, L., additional, and Risaliti, G., additional
- Published
- 2014
- Full Text
- View/download PDF
40. Iron K and Compton hump reverberation in SWIFT J2127.4+5654 and NGC 1365 revealed by NuSTAR and XMM–Newton
- Author
-
Kara, E., primary, Zoghbi, A., additional, Marinucci, A., additional, Walton, D. J., additional, Fabian, A. C., additional, Risaliti, G., additional, Boggs, S. E., additional, Christensen, F. E., additional, Fuerst, F., additional, Hailey, C. J., additional, Harrison, F. A., additional, Matt, G., additional, Parker, M. L., additional, Reynolds, C. S., additional, Stern, D., additional, and Zhang, W. W., additional
- Published
- 2014
- Full Text
- View/download PDF
41. SP848A SHARED PROTOCOL FOR CARDIOVASCULAR EVALUATION SIGNIFICANTLY REDUCES THE TIME FOR WAITLISTING THE POTENTIAL KIDNEY TRANSPLANT RECIPIENTS
- Author
-
Domenico Montanaro, Maria Groppuzo, Clotilde Vallone, Patrizia Tulissi, Gian Luigi Adani, Andrea Risaliti, Roberto Mioni, Daniela Miani, and Maria Gabriella Costa
- Subjects
Protocol (science) ,Transplantation ,medicine.medical_specialty ,Nephrology ,business.industry ,Internal medicine ,Medicine ,business ,Kidney transplant - Published
- 2015
42. Black hole spin and size of the X-ray-emitting region(s) in the Seyfert 1.5 galaxy ESO 362−G18
- Author
-
Agís-González, B., primary, Miniutti, G., additional, Kara, E., additional, Fabian, A. C., additional, Sanfrutos, M., additional, Risaliti, G., additional, Bianchi, S., additional, Strotjohann, N. L., additional, Saxton, R. D., additional, and Parker, M. L., additional
- Published
- 2014
- Full Text
- View/download PDF
43. The NuSTAR spectrum of Mrk 335: extreme relativistic effects within two gravitational radii of the event horizon?
- Author
-
Parker, M. L., primary, Wilkins, D. R., additional, Fabian, A. C., additional, Grupe, D., additional, Dauser, T., additional, Matt, G., additional, Harrison, F. A., additional, Brenneman, L., additional, Boggs, S. E., additional, Christensen, F. E., additional, Craig, W. W., additional, Gallo, L. C., additional, Hailey, C. J., additional, Kara, E., additional, Komossa, S., additional, Marinucci, A., additional, Miller, J. M., additional, Risaliti, G., additional, Stern, D., additional, Walton, D. J., additional, and Zhang, W. W., additional
- Published
- 2014
- Full Text
- View/download PDF
44. Search for X-ray occultations in active galactic nuclei
- Author
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Torricelli-Ciamponi, G., primary, Pietrini, P., additional, Risaliti, G., additional, and Salvati, M., additional
- Published
- 2014
- Full Text
- View/download PDF
45. PCA of PCA: principal component analysis of partial covering absorption in NGC 1365
- Author
-
Parker, M. L., primary, Walton, D. J., additional, Fabian, A. C., additional, and Risaliti, G., additional
- Published
- 2014
- Full Text
- View/download PDF
46. Simultaneous NuSTAR and XMM–Newton 0.5–80舁keV spectroscopy of the narrow-line Seyfert 1 galaxy SWIFT J2127.4+5654
- Author
-
Marinucci, A., primary, Matt, G., additional, Kara, E., additional, Miniutti, G., additional, Elvis, M., additional, Arevalo, P., additional, Ballantyne, D. R., additional, Baloković, M., additional, Bauer, F., additional, Brenneman, L., additional, Boggs, S. E., additional, Cappi, M., additional, Christensen, F. E., additional, Craig, W. W., additional, Fabian, A. C., additional, Fuerst, F., additional, Hailey, C. J., additional, Harrison, F. A., additional, Risaliti, G., additional, Reynolds, C. S., additional, Stern, D. K., additional, Walton, D. J., additional, and Zhang, W., additional
- Published
- 2014
- Full Text
- View/download PDF
47. The variable ionized absorber in the Seyfert 2 Mrk 348
- Author
-
Marchese, E., primary, Braito, V., additional, Reeves, J. N., additional, Ceca, R. Della, additional, Caccianiga, A., additional, Markowitz, A., additional, Risaliti, G., additional, Severgnini, P., additional, and Turner, T. J., additional
- Published
- 2013
- Full Text
- View/download PDF
48. A Chandra view of the clumpy reflector at the heart of the Circinus galaxy
- Author
-
Marinucci, A., primary, Miniutti, G., additional, Bianchi, S., additional, Matt, G., additional, and Risaliti, G., additional
- Published
- 2013
- Full Text
- View/download PDF
49. An examination of the spectral variability in NGC 1365 with Suzaku
- Author
-
Brenneman, L. W., primary, Risaliti, G., additional, Elvis, M., additional, and Nardini, E., additional
- Published
- 2013
- Full Text
- View/download PDF
50. X-ray absorption variability in NGC 4507
- Author
-
Marinucci, Andrea, primary, Risaliti, Guido, additional, Wang, Junfeng, additional, Bianchi, Stefano, additional, Elvis, Martin, additional, Matt, Giorgio, additional, Nardini, Emanuele, additional, and Braito, Valentina, additional
- Published
- 2013
- Full Text
- View/download PDF
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