相关论文: Weak emission line quasar SDSS J101353.45+492758.1…

We use the rms and lag spectra of the type-C quasi-periodic oscillation (QPO) to study the properties of the Comptonisation region (aka corona) during the low/hard and hard-intermediate states of the main outburst and reflare of MAXI…

We present the spatial analysis of five Compton thick (CT) active galactic nuclei (AGNs), including MKN 573, NGC 1386, NGC 3393, NGC 5643, and NGC 7212, for which high resolution Chandra observations are available. For each source, we find…

We identify a sample of 74 high-redshift quasars (z>3) with weak emission lines from the Fifth Data Release of the Sloan Digital Sky Survey and present infrared, optical, and radio observations of a subsample of four objects at z>4. These…

PKS J2310-437 is an AGN with bright X-ray emission relative to its weak radio emission and optical continuum. It is believed that its jet lies far enough from the line of sight that it is not highly relativistically beamed. It thus provides…

We present the analysis of the first NuSTAR observations ($\sim 220$ ks), simultaneous with the last SUZAKU observations ($\sim 50$ ks), of the active galactic nucleus of the bright Seyfert 1 galaxy Mrk 509. The time-averaged spectrum in…

We present medium and high resolution X-ray spectral study of a Seyfert 1 galaxy ESO~198--G24 using a long (122 ks) XMM-Newton observation performed in February 2006. The source has a prominent featureless soft X-ray excess below $2\kev$.…

We present the results from a joint Suzaku/NuSTAR broad-band spectral analysis of 3C 390.3. The high quality data enables us to clearly separate the primary continuum from the reprocessed components allowing us to detect a high energy…

We present a multi-epoch study of the extreme X-ray variability of the type~1 quasar SDSS~J000532.84+200717.4 using archival observations from \textit{XMM-Newton}, \textit{Swift}/XRT, \textit{EP-FXT}, and \textit{ROSAT}, together with new…

The X-ray spectra of the narrow line Seyfert 1 galaxy, 1H 0707-495, obtained with XMM-Newton, from time periods of varying X-ray luminosity are analysed in the context of understanding the changes to the X-ray emitting corona that lead to…

The spectral energy distributions of galactic black holes in the low/hard state and of low-luminosity AGN possess many common features, the most prominent being: compact, flat (or inverted) spectrum radio cores with high brightness…

The correlation between the X-ray and UV luminosities observed in quasars, spanning a wide redshift range and holding true for several decades in both spectral bands, suggests the presence of a universal mechanism governing the transfer of…

X-ray emission from AGN is believed to be produced via Comptonization of optical/UV seed photons emitted by the accretion disk, up-scattered by hot electrons in a corona surrounding the black hole. A critical compactness vs. temperature…

The physical conditions near the optical continuum peak (``hot spot'') in the inner narrow line region (NLR) of the Seyfert 2 galaxy, NGC 1068. Spectra were taken with HST/STIS through the 0.1X52 arcsec slit, covering the full STIS 1200 to…

We review the Seyfert 1.5 Galaxy ESO 362-G18 for exploring the origin of the soft X-ray excess. The Warm Corona and Relativistic Reflection models are two main scenarios to interpret the soft X-ray excess in AGNs at present. We use the…

The geometry of the accretion flow around stellar mass and supermassive black holes depends on the accretion rate. Broad iron emission lines originating from the irradiation of cool matter can indicate that there is an inner disk below a…

We have simultaneously fit Chandra and RXTE spectra of the Galactic black hole XTE J1118+480 with three models for X-ray reflection. We explored a range of accretion disc ionizations (log(xi)=1-4; xi=L_X/nR^{2}) and iron abundances…

We study the relationship between the UV and X-ray variability of the narrow-line Seyfert 1 galaxy 1H~0707-495. Using a year long {\it Swift} monitoring and four long {\it XMM-Newton} observations, we perform cross-correlation analyses of…

The soft X-ray excess in the spectra of active galactic nuclei is characterized by similar electron temperatures of 0.1 -- 0.3 keV and similar photon indices around 2.2 -- 3, if fitted with inverse Comptonization. It remains a puzzle why…

We present an XMM-Newton observation of the radio-quiet quasar Q0056-363 (z=0.162). This is the first time that this quasar is observed in the hard X-ray range (above 2 keV). We find that Q0056-363 is a powerful X-ray quasar, with a 0.3-12…

Merging luminous galaxies are ideal laboratories to study some of the most extreme astrophysical phenomena. The local (z=0.1232) obscured quasar J1356+1026 has two nuclei, North and South (J1356N and J1356S), but despite numerous efforts,…