scholarly journals Blueshifted absorption lines from X-ray reflection in IRAS 13224−3809

2020 ◽  
Vol 493 (2) ◽  
pp. 2518-2522 ◽  
Author(s):  
A C Fabian ◽  
C S Reynolds ◽  
J Jiang ◽  
C Pinto ◽  
L C Gallo ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Power Law ◽  
Galactic Nuclei ◽  
Absorption Lines ◽  
Narrow Line ◽  
X Ray ◽  
Absorbing Layer ◽  
Reflection Component

ABSTRACT We explore a disc origin for the highly blueshifted, variable absorption lines seen in the X-ray spectrum of the narrow-line Seyfert 1 galaxy IRAS 13224−3809. The blueshift corresponds to a velocity of ∼0.25c. Such features in other active galactic nuclei are often interpreted as ultrafast outflows. The velocity is of course present in the orbital motions of the inner disc. The absorption lines in IRAS 13224−3809 are best seen when the flux is low and the reflection component of the disc is strong relative to the power-law continuum. The spectra are consistent with a model in which the reflection component passes through a thin, highly ionized absorbing layer at the surface of the inner disc, the blueshifted side of which dominates the flux due to relativistic aberration (the disc inclination is about 70°). No fast outflow need occurs beyond the disc.

On the origin of power-law X-ray spectra of active galactic nuclei

1984 ◽  
Vol 287 ◽  
pp. 534 ◽  
Author(s):  
I. Schlosman ◽  
J. Shaham ◽  
G. Shaviv
Keyword(s):  
Active Galactic Nuclei ◽  
Power Law ◽  
Galactic Nuclei ◽  
X Ray

scholarly journals The coronal temperature of NGC 4388 and NGC 2110 measured with INTEGRAL

2019 ◽  
Vol 629 ◽  
pp. A54 ◽  
Author(s):  
F. Ursini ◽  
L. Bassani ◽  
A. Malizia ◽  
A. Bazzano ◽  
A. J. Bird ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Spherical Geometry ◽  
High Energy ◽  
Coronal Temperature ◽  
Signal To Noise ◽  
X Ray ◽  
Good Signal ◽  
High Energy Emission ◽  
Reflection Component

Aims. We aim to measure the physical properties of the hot X-ray corona of two active galactic nuclei, NGC 4388 and NGC 2110. Methods. We analysed the hard X-ray (20–300 keV) INTEGRAL spectrum in conjunction with archival XMM–Newton and NuSTAR data. Results. The X-ray spectrum of both sources is phenomenologically well described by an absorbed cut-off power law. In agreement with previous results, we find no evidence of a Compton reflection component in these sources. We obtain a high-energy cut-off of 200−40+75 keV for NGC 4388 and 320−60+100 keV for NGC 2110. A fit with a thermal Comptonisation model yields a coronal temperature of 80−20+40 keV and 75−15+20 keV, respectively, and an optical depth of approximately two, assuming a spherical geometry. The coronal temperature and luminosity of both sources are consistent with pair production that acts as a thermostat for the thermal plasma. These results emphasise the importance of good signal-to-noise X-ray data above 100 keV to probe the high-energy emission of AGNs.

scholarly journals X-ray variability of 104 active galactic nuclei

2012 ◽  
Vol 8 (S290) ◽  
pp. 37-40
Author(s):  
O. González-Martín ◽  
S. Vaughan
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Power Law ◽  
Galactic Nuclei ◽  
Power Law Model ◽  
Black Hole Mass ◽  
Periodic Oscillations ◽  
Fundamental Plane ◽  
X Ray ◽  
Single Power

AbstractWe have performed a uniform analysis of the power spectrum densities (PSDs) of 104 nearby (z<0.4) active galactic nuclei (AGN) using 209 XMM-Newton/pn observations, including several AGN classes. These PSDs span ≃ 3 decades in temporal frequencies, ranging from minutes to days. We have fitted each PSD to two models: (1) a single power-law model and (2) a bending power-law model. A fraction of 72% show significant variability. The PSD of the majority of the variable AGN was well described by a simple power-law with a mean index of α = 2.01±0.01. In 15 sources we found that the bending power law model was preferred with a mean slope of α = 3.08±0.04 and a mean bend frequency of 〈νb〉 ≃ 2 × 10−4 Hz. Only KUG 1031+398 (RE J1034+396) shows evidence for quasi-periodic oscillations. The ‘fundamental plane’ relating variability timescale, black hole mass, and luminosity is demonstrated using the new X-ray timing results presented here together with a compilation of the previously detected timescales from the literature.

scholarly journals Examining the physical conditions of a warm corona in active galactic nuclei accretion discs

2019 ◽  
Vol 491 (3) ◽  
pp. 3553-3561 ◽  
Author(s):  
D R Ballantyne
Keyword(s):  
Active Galactic Nuclei ◽  
Power Law ◽  
Galactic Nuclei ◽  
Accretion Discs ◽  
Internal Heating ◽  
One Dimensional ◽  
X Ray ◽  
Physical Conditions ◽  
Gas Layer ◽  
Hot Corona

ABSTRACT A warm corona at the surface of an accretion disc has been proposed as a potential location for producing the soft excess commonly observed in the X-ray spectra of active galactic nuclei (AGNs). In order to fit the observed data, the gas must be at temperatures of ∼1 keV and have an optical depth of τT ≈ 10–20. We present one-dimensional calculations of the physical conditions and emitted spectra of a τT = 10 or 20 gas layer subject to illumination from an X-ray power law (from above), a blackbody (from below), and a variable amount of internal heating. The models show that a warm corona with kT ∼ 1 keV can develop, producing a strong Comptonized soft excess, but only if the internal heating flux is within a relatively narrow range. Similarly, if the gas density of the layer is too large then efficient cooling will stop a warm corona from forming. The radiation from the hard X-ray power law is crucial in producing a warm corona, indicating that a warm and hot corona may coexist in AGN accretion discs, and their combined effect leads to the observed soft excess. Intense heating of a warm corona leads to steep X-ray spectra with ionized Fe K α lines, similar to those seen in some narrow-line Seyfert 1 galaxies.

scholarly journals EUV and Soft X-ray Evidence for Partially Ionized Gas in Active Galactic Nuclei

1996 ◽  
Vol 152 ◽  
pp. 45-49
Author(s):  
J.P.D. Mittaz ◽  
R. Lieu ◽  
S. Bowyer ◽  
C.-Y. Hwang ◽  
J. Lewis
Keyword(s):  
Active Galactic Nuclei ◽  
Power Law ◽  
Galactic Nuclei ◽  
Ionized Gas ◽  
X Ray ◽  
Partially Ionized ◽  
Best Fit

We present a synoptic study of active galactic nuclei (AGN) detected by EUVE. We also present complementary ROSAT PSPC spectra for these sources and for other AGN in directions of low galactic absorption. It is found that the best-fit power-law photon indices of the X-ray spectra at 0.1–2.4 keV are anti-correlated with their galactic hydrogen columns. The indices for the 0.9–2.4 keV range do not show such a correlation, and are considerably smaller (i.e. flatter). We discuss a number of possible interpretations of this correlation but only one of these, the presence of a partially ionized absorbing gas in the AGN, explains the observations satisfactorily. The ubiquity of this effect suggests that this component be may very common in AGN.

scholarly journals X-ray power law spectra in active galactic nuclei

2010 ◽  
Vol 512 ◽  
pp. A58 ◽  
Author(s):  
W. Ishibashi ◽  
T. J.-L. Courvoisier
Keyword(s):  
Active Galactic Nuclei ◽  
Power Law ◽  
Galactic Nuclei ◽  
X Ray

scholarly journals Swift monitoring and Suzaku spectroscopy of the γ-ray detected narrow-line Seyfert 1 galaxy 1H 0323+342

2014 ◽  
Vol 10 (S312) ◽  
pp. 66-67
Author(s):  
S. Yao ◽  
W. Yuan ◽  
S. Komossa ◽  
D. Grupe ◽  
L. Fuhrmann ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Broad Band ◽  
Galactic Nuclei ◽  
Optical Monitoring ◽  
Narrow Line ◽  
Black Hole Mass ◽  
X Ray ◽  
Small Black Hole ◽  
Special Subset ◽  
Γ Ray

Abstract1H 0323+342 is one of the rare γ-ray detected narrow-line Seyfert 1 galaxies (NLS1s), a special subset of active galactic nuclei (AGN) owing to their hybrid behavior of both NLS1s and blazars. The rarity of such kind of sources makes their properties far from being understood. We analyze simultaneous X-ray and UV/optical monitoring observations of 1H 0323+342 performed by Swift over ~7 years. The UV/X-ray correlation and the broad band SED reveal that the X-ray band is dominated by the disk/corona emission during the observations. The large normalized excess variance of the X-ray variability detected with Suzaku suggests a relatively small black hole mass of the order of 107M⊙, consistent with the estimation based on the broad Hβ line in the optical band.

scholarly journals Ensemble quasar spectral variability from the XMM-Newton Serendipitous Source Catalogue

2016 ◽  
Vol 12 (S324) ◽  
pp. 249-250
Author(s):  
Roberto Serafinelli ◽  
Fausto Vagnetti ◽  
Riccardo Middei
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Spectral Slope ◽  
High Luminosity ◽  
Spectral Variability ◽  
General Behaviour ◽  
Large Sample ◽  
X Ray ◽  
Spectral Models ◽  
Reflection Component

AbstractVariations of the X-ray spectral slope have been found in many Active Galactic Nuclei (AGN) at moderate luminosities and redshifts, typically showing a “softer when brighter” behaviour. However, similar studies are not usually performed for high-luminosity AGNs. We present an analysis of the spectral variability based on a large sample of quasars in wide intervals of luminosity and redshift, measured at several different epochs, extracted from the fifth release of the XMM Newton Serendipitous Source Catalogue. Our analysis confirms a “softer when brighter” trend also for our sample, extending to high luminosity and redshift the general behaviour previously found. These results can be understood in light of current spectral models, such as intrinsic variations of the X-ray primary radiation, or superposition with a constant reflection component.

scholarly journals 15-GHz radio emission from nearby low-luminosity active galactic nuclei

2018 ◽  
Vol 616 ◽  
pp. A152 ◽  
Author(s):  
Payaswini Saikia ◽  
Elmar Körding ◽  
Deanne L. Coppejans ◽  
Heino Falcke ◽  
David Williams ◽  
...  
Keyword(s):  
Black Hole ◽  
Radio Emission ◽  
Active Galactic Nuclei ◽  
Power Law ◽  
Critical Mass ◽  
Galactic Nuclei ◽  
Radio Luminosity ◽  
Solar Mass ◽  
Fundamental Plane ◽  
X Ray

We present a sub-arcsec resolution radio imaging survey of a sample of 76 low-luminosity active galactic nuclei (LLAGN) that were previously not detected with the Very Large Array at 15 GHz. Compact, parsec-scale radio emission has been detected above a flux density of 40 μ Jy in 60% (45 of 76) of the LLAGN sample. We detect 20 out of 31 (64%) low-ionization nuclear emission-line region (LINER) nuclei, ten out of 14 (71%) low-luminosity Seyfert galaxies, and 15 out of 31 (48%) transition objects. We use this sample to explore correlations between different emission lines and the radio luminosity. We also populate the X-ray and the optical fundamental plane of black hole activity and further refine its parameters. We obtain a fundamental plane relation of log LR = 0.48 (±0.04) log LX + 0.79 (±0.03) log M and an optical fundamental plane relation of log LR = 0.63 (±0.05) log L[O III] + 0.67 (±0.03) log M after including all the LLAGN detected at high resolution at 15 GHz, and the best-studied hard-state X-ray binaries (luminosities are given in erg s−1 while the masses are in units of solar mass). Finally, we find conclusive evidence that the nuclear 15 GHz radio luminosity function (RLF) of all the detected Palomar Sample LLAGN has a turnover at the low-luminosity end, and is best-fitted with a broken power law. The break in the power law occurs at a critical mass accretion rate of 1.2 × 10−3 M⊙ yr−1, which translates to an Eddington ratio of ṁEdd ~ 5.1 × 10−5, assuming a black hole mass of 109 M⊙. The local group stands closer to the extrapolation of the higher-luminosity sources, and the classical Seyferts agree with the nuclear RLF of the LLAGN in the local universe.

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