Exploring the spectral variability of the Seyfert 1.5 galaxy Markarian 530 with Suzaku

Monthly Notices of the Royal Astronomical Society

et al. 2019

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We have carried out a systematic analysis of the nearby (z=0.0279) active galaxy Zw 229.015 using multi-epoch, multi-instrument and deep pointed observations with XMM-Newton, Suzaku, Swift and NuSTAR. Spectral and temporal variability are examined in detail on both the long (weeks-to-years) and short (hours) timescales. A deep Suzaku observation of the source shows two distinct spectral states; a bright-soft state and a dim-hard state in which changes in the power law component account for the differences. Partial covering, blurred reflection and soft Comptonisation models describe the X-ray spectra comparably well, but the smooth, rather featureless, spectrum may be favouring the soft Comptonisation scenario. Moreover, independent of the spectral model, the observed spectral variability is ascribed to the changes in the power law continuum only and do not require changes in the properties of the absorber or blurred reflector incorporated in the other scenarios. The multi-epoch observations between 2009 and 2018 can be described in similar fashion. This could be understood if the primary emission is originating at a large distance from a standard accretion disc or if the disc is optically thin and geometrically thick as recently proposed for Zw 229.015. Our investigation shows that Zw 229.015 behaves similar to sources like Akn 120 and Mrk 530, that exhibit a strong soft-excess, but weak Compton hump and Fe Kα emission.

Section: Rapid X-ray Variabilitysupporting

confidence: 69%

“…Zw 229.015 exhibits a blend of curious features similar to features exhibited by sources like Akn 120 (e.g. Vaughan et al 2004;Matt et al 2014;Porquet et al 2018) and Mrk 530 (Ehler et al 2018). Zw 229.015 shows a soft excess that is gently increasing above the power law starting at about 2 keV toward lower energies.…”

Section: Origin Of the Soft Excessmentioning

confidence: 91%

The nature of the soft excess and spectral variability in the Seyfert 1 galaxy Zw 229.015

Tripathi

Monthly Notices of the Royal Astronomical Society

et al. 2019

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“…Furthermore, ionised iron emission features have been reported in both NLS1 and BLS1 AGN (e.g. Patrick et al 2012;Mantovani et al 2016;Ehler et al 2018;Waddell et al 2019). Overall, this suggests that the presence of ionised iron emission is similar for NLS1 and BLS1 galaxies.…”

Section: Modelling Proceduresmentioning

confidence: 70%

A Suzaku sample of unabsorbed narrow-line and broad-line Seyfert 1 galaxies – I. X-ray spectral properties

Monthly Notices of the Royal Astronomical Society

2020

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A sample of narrow-line (NLS1) and broad-line Seyfert 1 (BLS1) galaxies observed with Suzaku is presented. The final sample consists of 22 NLS1s and 47 BLS1s, for a total of 69 AGN that are all at low redshift (z < 0.5) and exhibit low host galaxy column densities (<1022 cm−2 ). The average spectrum for each object is fit with a toy model to characterise important parameters, including the photon index, soft excess, Compton hump (or hard excess), narrow iron line strength, luminosity and X-ray Eddington ratio (Lx/LEdd). We confirm previous findings that NLS1s have steeper power laws and higher X-ray Eddington ratios, but also find that NLS1 galaxies have stronger soft and hard excesses than their BLS1 counterparts. Studying the correlations between parameters shows that the soft and hard excesses are correlated for NLS1 galaxies, while no such correlation is observed for BLS1s. Performing a principal component analysis (PCA) on the measured X-ray parameters shows that while the X-ray Eddington ratio is the main source of variations within our sample (PC1), variations in the soft and hard excesses form the second principal component (PC2) and it is dominated by the NLS1s. The correlation between the soft and hard excess in NLS1 galaxies may suggest a common origin for the two components, such as a blurred reflection model. The presented Suzaku sample of Seyfert 1 galaxies is a useful tool for analysis of the X-ray properties of AGN, and for the study of the soft and hard excesses observed in AGN.

“…This feature is seen in some AGN including Ark 120 (e.g. Vaughan et al 2004;Porquet et al 2018), Mrk 530 (Ehler et al 2018), and Zw 229.015 (Tripathi et al 2019). A separate source of emission is then required to explain the presence of Fe Kα lines and other emission features.…”

Section: Introductionmentioning

confidence: 99%

Multi-epoch X-ray spectral analysis of the narrow-line Seyfert 1 galaxy Mrk 478

Monthly Notices of the Royal Astronomical Society

Gonzalez

et al. 2019

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A multi-epoch X-ray spectral and variability analysis is conducted for the narrow-line Seyfert 1 (NLS1) active galactic nucleus (AGN) Mrk 478. All available X-ray data from XMM-Newton and Suzaku satellites, spanning from 2001 to 2017, are modelled with a variety of physical models including partial covering, soft-Comptonisation, and blurred reflection, to explain the observed spectral shape and variability over the 16 years. All models are a similar statistical fit to the data sets, though the analysis of the variability between data sets favours the blurred reflection model. In particular, the variability can be attributed to changes in flux of the primary coronal emission. Different reflection models fit the data equally well, but differ in interpretation. The use of REFLIONX predicts a low disc ionisation and power law dominated spectrum, while RELXILL predicts a highly ionised and blurred reflection dominated spectrum. A power law dominated spectrum might be more consistent with the normal X-rayto-UV spectral shape (α ox ). Both blurred reflection models suggest a rapidly spinning black hole seen at a low inclination angle, and both require a sub-solar (∼ 0.5) abundance of iron. All physical models require a narrow emission feature at 6.7 keV likely attributable to Fe XXV emission, while no evidence for a narrow 6.4 keV line from neutral iron is detected.