Discovery of the Narrow-Line Seyfert 1 Galaxy Markarian 335 in a Historical Low X-Ray Flux State

Grupe, D.; Komossa, Stefanie; Gallo, Luigi

doi:10.1086/523042

Cited by 72 publications

(127 citation statements)

References 44 publications

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“…The ∼ 0.9 keV feature was not required in the high-flux spectrum with the normalisation being consistent with zero when a Gaussian profile was included. The emission feature is comparable in flux and energy to that reported by Grupe et al (2007) The residuals to this model portray an absorption-like feature at approximately 7 keV in the low-flux spectrum that could arise from highly ionised iron in a warm absorber. Longinotti et al (2013) modeled the complex absorption seen in the intermediate flux-state of Mrk 335 with a triple-zone warm absorber.…”

Section: Blurred Reflection Fits For the Multi-epoch Spectral Datasupporting

confidence: 75%

“…The low-flux spectra are identical above 2 keV, but the XMM-Newton spectrum exhibits excess emission below that energy. This excess emission could be from the ionised emitter that was present at that time (Grupe et al 2007;Longinotti et al 2008). The ratio of the difference spectrum (2006FI data -2013 from the high-flux spectrum) fitted with a power law between 2.5 − 10 keV reveals significant changes in the Fe Kα band and below about 2 keV.…”

Section: The Spectral Characteristics In the High-and Low-statementioning

confidence: 93%

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Suzaku observations of Mrk 335: confronting partial covering and relativistic reflection

Gallo

Wilkins

Bonson

et al. 2014

Monthly Notices of the Royal Astronomical Society

101

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We report on the deepest X-ray observation of the narrow-line Seyfert 1 galaxy Mrk 335 in the low-flux state obtained with Suzaku. The data are compared to a 2006 high-flux Suzaku observation when the source was ∼ 10× brighter. Describing the two flux levels self-consistently with partial covering models would require extreme circumstances, as the source would be subject to negligible absorption during the bright state and ninety-five per cent covering with near Compton-thick material when dim. Blurred reflection from an accretion disc around a nearly maximum spinning black hole (a > 0.91, with preference for a spin parameter as high as ∼ 0.995) appears more likely and is consistent with the long-term and rapid variability. Measurements of the emissivity profile and spectral modelling indicate the high-flux Suzaku observation of Mrk 335 is consistent with continuum-dominated, jet-like emission (i.e. beamed away from the disc). It can be argued that the ejecta must be confined to within ∼ 25 r g if it does not escape the system. During the low-flux state the corona becomes compact and only extends to about 5 r g from the black hole, and the spectrum becomes reflectiondominated. The low-frequency lags measured at both epochs are comparable indicating that the accretion mechanism is not changing between the two flux levels. Various techniques to study the spectral variability (e.g. principal component analysis, fractional variability, difference spectra, and hardness ratio analysis) indicate that the low-state variability is dominated by changes in the power law flux and photon index, but that changes in the ionisation state of the reflector are also required. Most notably, the ionisation parameter becomes inversely correlated with the reflected flux after a long-duration flare-like event during the observation.

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Section: Blurred Reflection Fits For the Multi-epoch Spectral Datasupporting

confidence: 75%

Section: The Spectral Characteristics In the High-and Low-statementioning

confidence: 93%

Suzaku observations of Mrk 335: confronting partial covering and relativistic reflection

Gallo

Wilkins

Bonson

et al. 2014

Monthly Notices of the Royal Astronomical Society

101

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“…Holt et al 1980;Reichert et al 1985;Boller et al 2002Boller et al , 2003Immler et al 2003;Tanaka et al 2004;Gallo et al 2004a,b;Pounds et al 2004;Turner et al 2005;Grupe et al 2007, inter alia). previously tested a partial covering model for the 2001 XMM-Newton spectrum of MCG-6-30-15 and concluded that, although such a model provided an acceptable fit, a relativistically-blurred model was superior.…”

Section: The Role Of Absorber Partial Coveringmentioning

confidence: 98%

An absorption origin for the X-ray spectral variability of MCG–6-30-15

Miller¹,

Turner

Reeves

2008

A&A

198

261

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Context. The Seyfert I galaxy MCG-6-30-15 shows one of the best examples of a broad "red wing" of emission in its X-ray spectrum at energies 2 < E < 6.4 keV, commonly interpreted as being caused by relativistically-blurred reflection close to the event horizon of the black hole. Aims. We aim to test an alternative model in which absorption creates the observed spectral shape, explains the puzzling lack of variability of the red wing and reduces the high reflection albedo, substantially greater than unity, that is otherwise inferred at energies E > 20 keV.Methods. We compiled all the available long-exposure, high-quality data for MCG-6-30-15: 522 ks of Chandra hetgs, 282 ks of XMM-Newton pn/rgs and 253 ks of Suzaku xis/pin data. This is the first analysis of this full dataset. We investigated the spectral variability on timescales >20 ks using principal components analysis and fitted spectral models to "flux state" and mean spectra over the energy range 0.5−45 keV (depending on detector). The absorber model was based on the zones previously identified in the highresolution grating data. Joint fits were carried out to any data that were simultaneous. Results. Multiple absorbing zones covering a wide range of ionisation are required by the grating data, including a highly ionised outflowing zone. A variable partial-covering zone plus absorbed low-ionisation reflection, distant from the source, provides a complete description of the variable X-ray spectrum. A single model fits all the data. We conclude that these zones are responsible for the red wing, its apparent lack of variability, the absorption structure around the Fe Kα line, the soft-band "excess" and the high flux seen in the hard X-ray band. A relativistically-blurred Fe line is not required in this model. We suggest the partial covering zone is a clumpy wind from the accretion disk.

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“…Despite their different shape in the Fe-line energy region, the superposition of different layers of partially-ionised absorbing material could mimic the presence of a broad line component superimposed to the continuum, a feature naturally present in a relativistically-blurred, ionized reflection model (see e.g. Reeves et al 2004;Grupe et al 2007;Petrucci et al 2007 Table 3). …”

Section: The Emission At Energies >3 5 Kevmentioning

confidence: 99%

X-ray spectral variability in PG 1535+547: the changing look of a “soft X-ray weak” AGN

Ballo¹,

Giustini

Schartel³

et al. 2008

A&A

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Context. PG 1535+547 is a bright Narrow Line Seyfert 1 galaxy, whose high-energy emission shows strong variability both in shape and flux. On the basis of ROSAT observations, it is classified as "soft X-ray weak quasi-stellar object (QSO)", a class of objects whose X-ray-to-optical flux ratio is smaller than in typical QSOs. Their X-ray spectra are often characterized by highly-ionized, complex absorbers and/or reflection from the inner accretion disk, and the relative importance of the two is currently debated. Whatever the correct interpretation may be, the presence of such features implies that we are looking at matter located in the innermost regions of these AGN. Aims. We want to clarify the nature of the X-ray emission of PG 1535+547, and constrain the physical properties of its innermost regions, where this emission originates. Methods. We present new XMM-Newton observations of PG 1535+547 (90 ks exposure time, January 2006), from which we obtained two spectra European Photon Imaging Camera (EPIC) separated by about one week. We compare these spectra with those from a previous (November 2002) XMM-Newton observation. Results. These latest observations support the complex and variable nature of the X-ray emission of PG 1535+547. The broadband observed flux increases by a factor ∼2.3 in three years, and then decreases by a factor ∼1.3 in about one week. In the new spectra, strong absorption features at E < 3 keV and a complex spectral shape in the iron-line energy range are evident, coupled with a drop in the emission at higher energies. We describe all the different states in a consistent way, assuming either a warm absorber plus a relativistically-blurred ionized reflection, or a two-phase warm absorber partially covering the source with the addition of a scattered component. Conclusions. The observed variability can be ascribed mostly to warm absorbing gas in the innermost regions of PG 1535+547, which appears to vary in its physical properties on timescales of both years and days. In the blurred reflection scenario, all the analyzed states require a high fraction of reflection from the disk, calling for some mechanisms able to increase the reflection component with respect to the intrinsic continuum. Finally, the strong variability observed in the X-ray band opposed to a more constant emission at optical frequencies, changes the value of the X-ray-to-optical spectral index, implying that PG 1535+547 can not actually be classified as a soft X-ray weak active galactic nucleus (AGN).

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Discovery of the Narrow-Line Seyfert 1 Galaxy Markarian 335 in a Historical Low X-Ray Flux State

Cited by 72 publications

References 44 publications

Suzaku observations of Mrk 335: confronting partial covering and relativistic reflection

Suzaku observations of Mrk 335: confronting partial covering and relativistic reflection

An absorption origin for the X-ray spectral variability of MCG–6-30-15

X-ray spectral variability in PG 1535+547: the changing look of a “soft X-ray weak” AGN

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