Rapid Compton-thick/Compton-thin Transitions in the Seyfert 2 Galaxy NGC 1365

Risaliti, G.; Elvis, M.; Fabbiano, G.; Baldi, A.; Zezas, A.

doi:10.1086/430252

Cited by 277 publications

(288 citation statements)

References 23 publications

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“…Dramatic changes of the column density and/or the ionization state of the absorber have already been observed in other sources, the most spectacular being NGC 4151 (e.g. Schurch & Warwick 2002;de Rosa et al 2007), NGC 7582 (Bianchi et al 2009), and NGC 1365 (Risaliti et al 2005(Risaliti et al , 2009). In the last two sources in particular considerable variations of the column density of the (cold) absorber occur on time scales as short as less than a day.…”

Section: Discussionmentioning

confidence: 67%

Extreme warm absorber variability in the Seyfert galaxy Mrk 704

Matt

Bianchi

Guainazzi

et al. 2011

A&A

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Context. In about half of the Seyfert galaxies, the X-ray emission is absorbed by an optically thin, ionized medium, the so-called "warm absorber", whose origin and location is still a matter of debate. Aims. The aim of this paper is to constrain the warm absorber further by studying its variability. Methods. We analyzed the X-ray spectra of a Seyfert 1 galaxy, Mrk 704, which was observed twice, three years apart, by XMM-Newton. Results. The spectra were well fitted with a two-zones absorber, which possibly covers the source only partially. The parameters of the absorbing matter -column density, ionization state, covering factor -changed significantly between the two observations. Possible explanations for the more ionized absorber are a torus wind (the source is a polar scattering one) or, in the partial covering scenario, an accretion disk wind. The less ionized absorber is possibly composed of orbiting clouds in the surroundings of the nucleus, similarly to what was already found in other sources, most notably NGC 1365.

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Section: Discussionmentioning

confidence: 67%

Extreme warm absorber variability in the Seyfert galaxy Mrk 704

Matt

Bianchi

Guainazzi

et al. 2011

A&A

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“…1.5×10 7 M (Bian & Zhao 2003) and 1.2×10 8 M (Winter et al 2010). Applying a bolometric correction of 30 to the observed 2-10 keV luminosity (as appropriate in this luminosity range, according to Marconi et al 2004), we recover L bol /L edd 0.1−1.…”

Section: A Global Scenariomentioning

confidence: 77%

“…Bianchi et al 2008a;Panessa et al 2009), to act as a Compton-thick X-ray absorber in others (e.g. Elvis et al 2004;Risaliti et al 2005;Puccetti et al 2007;Bianchi et al 2009b), or even to produce most of the observed neutral iron Kα line, when no other evidence of the torus could be found in the data (Bianchi et al 2008b). …”

Section: Introductionmentioning

confidence: 99%

The broad-band X-ray spectrum of the Seyfert 1 galaxy, MCG+8-11-11

Bianchi

Angelis

Matt

et al. 2010

A&A

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Aims. Evidence is mounting that the main ingredients of the unification models of active galactic nuclei may behave differently from expectations, and be intimately related to fundamental physical parameters. The availability of high signal-to-noise broad-band X-ray spectra provides us with the opportunity to study in detail all the contributions from the materials invoked in these models, and infer their general properties, including whether their presence or absence is related to other quantities. Methods. We present a long (100 ks) Suzaku observation of one of the X-ray brightest AGN, MCG+8-11-11. These data are complemented with the 54-month Swift BAT spectrum, allowing us to perform a broad-band fit to the 0.6-150 keV range. Results. The fits performed in the 0.6-10 keV band provide results consistent with those of a a previous XMM-Newton observation, i.e. a lack of a soft excess, warm absorption along the line of sight, a large Compton reflection component (R 1), and an absence of a relativistic component of the neutral iron Kα emission line. However, when the PIN and Swift BAT data are included, the reflection amount drops significantly (R 0.2−0.3), and a relativistic iron line is required, the latter being confirmed by a phenomenological analysis in a restricted energy band (3-10 keV). When a self-consistent model is applied to the whole broad-band data, the observed reflection component appears to be entirely associated with the relativistic component of the iron Kα line. Conclusions. The implied scenario, though strongly model-dependent, requires that all the reprocessing spectral components from Compton-thick material be associated with the accretion disc, and no evidence of a classical pc-scale torus is found. The narrow core of the neutral iron Kα line is therefore produced in Compton-thin material, such as the BLR, similarly to what is found in another Seyfert galaxy, NGC 7213, but with the notable difference that MCG+8-11-11 presents spectral signatures from an accretion disc. The very low accretion rate of NGC 7213 could explain the lack of relativistic signatures in its spectrum, but the absence of the torus in both sources is more difficult to explain, since their luminosities are comparable, and their accretion rates are completely different.

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“…6.1 V404 Cyg: an obscured super-Eddington AGN-analogue Both significant reflected emission (see, e.g., NGC 7582, Bianchi et al 2009 andRivers et al 2015) and the effects of a patchy, neutral absorber (see, e.g., the case of NGC 4151, Zdziarski et al 2002, de Rosa et al 2007and NGC 1365, Risaliti et al 2005) are sometimes seen in obscured AGN, where the variability of the absorber is thought to be responsible of most of the variability from the source.…”

Section: Discussionmentioning

confidence: 99%

The black hole binary V404 Cygni: a highly accreting obscured AGN analogue

Motta

Kajava

Sánchez–Fernández

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Typical black hole binaries in outburst show spectral states and transitions, characterized by a clear connection between the inflow onto the black hole and outflows from its vicinity. The transient stellar mass black hole binary V404 Cyg apparently does not fit in this picture. Its outbursts are characterized by intense flares and intermittent plateau and low-luminosity states, with a dynamical intensity range of several orders of magnitude on time-scales of hours. During the 2015 June-July X-ray outburst a joint Swift and INTEGRAL observing campaign captured V404 Cyg in one of these plateau states. The simultaneous Swift/XRT and INTE-GRAL /JEM-X/ISGRI spectrum is reminiscent of that of obscured/absorbed AGN. It can be modelled as a Comptonization spectrum, heavily absorbed by a partial covering, high-column density material (N H ≈ 1 − 3 × 10 24 cm −2 ), and a dominant reprocessed component, including a narrow Iron-Kα line. Such spectral distribution can be produced by a geometrically thick accretion flow able to launch a clumpy outflow, likely responsible for both the high intrinsic absorption and the intense reprocessed emission observed. Similarly to what happens in certain obscured AGN, the low-flux states might not be (solely) related to a decrease in the intrinsic luminosity, but could instead be caused by an almost complete obscuration of the inner accretion flow.

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Rapid Compton-thick/Compton-thin Transitions in the Seyfert 2 Galaxy NGC 1365

Cited by 277 publications

References 23 publications

Extreme warm absorber variability in the Seyfert galaxy Mrk 704

Extreme warm absorber variability in the Seyfert galaxy Mrk 704

The broad-band X-ray spectrum of the Seyfert 1 galaxy, MCG+8-11-11

The black hole binary V404 Cygni: a highly accreting obscured AGN analogue

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