Warm absorbers in Narrow-Line Seyfert 1 galaxies

The Narrow-line Seyfert 1 galaxy RXJ0134.3-4258 was detected during the ROSAT all-sky survey with an ultrasoft spectrum (Greiner 1996). Our later pointed observation led to the discovery of drastic spectral variability. Here, we present the first detailed analysis of the soft X-ray properties of this peculiar source.

The Narrow-line Seyfert 1 galaxy NGC 4051 is known to exhibit significant X-ray spectral/flux variations and have a number of emission/absorption features. X-ray observations have revealed that these absorption features are blueshifted, which indicates that NGC 4051 has warm absorber outflow. In order to constrain physical parameters of the warm absorber outflow, we analyze the archival data with the longest exposure taken by XMM-Newton in 2009. We calculate the root-mean-squ...

The bright Seyfert 1 galaxy H1419+480 (z~0.072), whose X-ray colours from earlier HEAO-1 and ROSAT missions suggested a complex X-ray spectrum, has been observed with XMM-Newton. The EPIC spectrum above 2 keV is well fit by a power-law with photon index \Gamma=1.84\pm 0.01 and an Fe Ka line of equivalent width ~250 eV. At softer energies, a decrement with respect to this model extending from 0.5 to 1 keV is clearly detected. After trying a number of models, we find that the b...

Narrow Line Seyfert 1 (NLSy1) galaxies have recently received a lot of attention due to their unusual optical--X-ray properties which are not yet well understood. Photoionization models of the circum-nuclear emission/absorption regions allow to investigate scenarios to explain the main characteristics of NLSy1s, i.e., (i) extremely steep X-ray spectra within the ROSAT energy range, (ii) narrow Balmer lines and (iii) weak forbidden lines except for some relatively strong high-...

The Seyfert 1 galaxy, NGC3516 has been the subject of many absorption line studies at both ultraviolet and X-ray wavelengths. In the UV, strong, broad, variable associated metal line absorption with velocity width $\sim 2000$ \kms\ is thought to originate in gas with nh larger than about $10^{19}$ cm$^{-2}$ lying between 0.01 and 9 pc from the central active nucleus. The Ginga X-ray data are consistent with several possibilities: a warm absorber and a cold absorber combined e...

We report the discovery of RX J2317.8-4422 in an extremely low X-ray flux state by the Neil Gehrels Swift observatory in 2014 April/May. In total, the low-energy X-ray emission dropped by a factor 100. We have carried out multi-wavelength follow-up observations of this Narrow-Line Seyfert 1 galaxy. Here we present observations with Swift, XMM-Newton, and NuSTAR in October and November 2014 and further monitoring observations by Swift from 2015 to 2018. Compared with the begin...

X-ray observations of unabsorbed active galactic nuclei provide an opportunity to explore the innermost regions of supermassive black hole accretion discs. Our goal in this paper is to investigate the central environment of a Seyfert 1.5 galaxy IRAS 05078+1626. We studied the time-averaged spectrum obtained with the EPIC and RGS instruments. A power-law continuum (photon index ~ 1.75) dominates the 2-10 keV energy range. A narrow iron K alpha spectral line is clearly seen, pr...

Warm absorbers are an important new probe of the central regions of active galaxies. So far, they revealed their existence mainly in the soft X-ray spectral region. In observing and modeling this component, we can learn a lot about the nature of the warm absorber itself, its relation to other components of the active nucleus, and the intrinsic AGN X-ray spectral shape. Here, we briefly review the basic X-ray spectral features of warm absorbers (dust-free WAs, dusty WAs, pec...

We present the first detailed X-ray analysis of three AGN, the Seyfert 1 galaxies UGC 3142 and ESO 140-43, and the Seyfert 2 galaxy ESO 383-18, in order to study the geometry and the physical characteristics of their absorbers. High quality XMM-Newton EPIC and RGS data were analysed, as well as Swift/XRT and BAT and INTEGRAL IBIS/ISGRI data, in order to cover the 0.3--110 keV energy range. For ESO 140-43 also XMM-Newton/OM and Swift/UVOT data were used. We studied the variabi...

We present a detailed analysis of the complex absorption apparent in the 2-6 keV X-ray spectrum of the bright nearby Seyfert galaxy NGC 4151. We first utilize the large bandpass and medium spectral resolution afforded by BeppoSAX data to construct a 1-100 keV spectral template, which assumes the absorption arises in both warm (i.e. partially photoionized) and cold gas present in the line of sight to the active nucleus of the source. Application of this spectral model to an AS...