Related papers: Variable X-ray reflection from 1H~0419--577
We report on a 100 ks Suzaku observation of the bright, nearby (z=0.008486) Seyfert 1.9 galaxy MCG -5-23-16. The broad-band (0.4-100 keV) X-ray spectrum allows us to determine the nature of the high energy emission with little ambiguity.…
The soft (\approx 0.1--2.0 keV) X-ray spectra of narrow-line Seyfert 1 galaxies are known to be generally steeper than those of Seyfert 1 galaxies with broader optical permitted lines. This has been attributed to the presence of strong soft…
In this paper we present a temporal and spectral analysis of X-ray data from the XMM and Chandra observations of the ultrasoft and variable Seyfert galaxy RX J1301.9+2747. In both observations the source clearly displays two distinct states…
MCG-6-30-15, at a distance of 37 Mpc (z=0.008), is the archetypical Seyfert 1 galaxy showing very broad Fe K$\alpha$ emission. We present results from a joint NuSTAR and XMM-Newton observational campaign that, for the first time, allows a…
We investigate the relationship between the long term X-ray spectral variability in the Seyfert 1.5 galaxy NGC 4151 and its intrinsic absorption, by comparing the 2014 simultaneous ultraviolet/X-Ray observations taken with Hubble STIS…
We present the results from a study of the X-ray variability and the near-IR to X-ray spectral energy distribution of four low-luminosity, Seyfert 1 galaxies. We compared their variability amplitude and broad band spectrum with those of…
Aims: We used data from the 58 month long, continuous Swift/Burst Alert Telescope (BAT) observations of the five brightest Seyfert galaxies at hard X-rays, to study their flux and spectral variability in the 20-100 keV energy band. The…
We present our investigation into the long-term variability of the X-ray obscuration and optical-UV-X-ray continuum in the Seyfert 1 galaxy NGC 5548. In 2013 and 2014, the Swift observatory monitored NGC 5548 on average every day or two,…
The first seven years of RXTE monitoring of Seyfert 1 active galactic nuclei have been systematically analyzed to yield five homogeneous samples of 2-12 keV light curves, probing hard X-ray variability on successively longer durations from…
We present a complete analysis of the hard X-ray (2-10 keV) properties of the Seyfert galaxy NGC 1365, based on a 60 ks XMM-Newton observation performed in January 2004. The two main results are: 1) We detect an obscuring cloud with…
We analyze the X-ray, optical, and mid-infrared data of a "changing-look" Seyfert galaxy \sdssj15 at $z\simeq0.086$. Over a period of one decade (2009 - 2018), its broad H$\alpha$ line intensity increased by a factor of $\sim$4. Meanwhile,…
We investigate the origin of the soft X-ray excess emission from narrow-line Seyfert 1 galaxies Akn564 and Mrk1044 using XMM-Newton observations. We find clear evidence for time delays between the soft and hard X-ray emission from Akn564…
We present results from the coordinated broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 performed by NuSTAR, XMM-Newton and Suzaku in late 2012. These observations provide the first high-quality…
We report results from a 2003 FUSE observation, and reanalysis of a 1996 HST observation of the unusual X-ray transient Narrow-line Seyfert 1 galaxy WPVS 007. The HST FOS spectrum revealed mini-BALs with V_max ~ 900 km s^-1 and FWHM ~ 550…
The EPIC detectors on XMM-Newton provide the most sensitive broad band (0.3-12 keV) X-ray spectra to date. Observations of 6 Seyfert 1 galaxies, covering a wide luminosity range, are examined with the aim of identifying the primary X-ray…
We report the discovery of a luminous ultra-soft X-ray excess in a radio-loud narrow-line Seyfert1 galaxy, RXJ1633+4718, from archival ROSAT observations. The thermal temperature of this emission, when fitted with a blackbody, is as low as…
We present new results of uniform spectral analysis of Swift/XRT observations of the X-ray binary system 4U 1957+11. This includes 26 observations of the source made between MJD 54282$-$55890 (2007 July 01 $-$ 2011 November 25). All 26…
We present an analysis of the X-ray spectra of a sample of 37 observations of 26 Seyfert galaxies observed by XMM-Newton in order to characterize their iron K emission. All objects show evidence for iron line emission in the 6-7 keV band. A…
We have analyzed a long-look Suzaku observation of the Seyfert 1.2 Mkn~590. We aimed to measure the Compton reflection strength, Fe K complex properties and soft excess emission as had been observed previously in this source. The Compton…
To investigate further the comparison between AGN and black hole X-ray binaries, we have studied the main X-ray variability properties of the Seyfert 1 Galaxy Markarian 335. We put particular emphasis on the X-ray time lags, which is a…