The long-term X–ray variability properties of AGN in the Lockman Hole region
نویسندگان
چکیده
Context. We present the results from a detailed X–ray variability analysis of 66 AGN in the Lockman Hole, which have optical spectroscopic identifications. Aims. We compare, quantitatively, their variability properties with the properties of local AGN, and we study the “variability – luminosity” relation as a function of redshift, and the “variability – redshift” relation in two luminosity
منابع مشابه
A brief review of long - term X - ray and optical variability in radio - quiet AGN
Long-time-scale X-ray and optical variability is a key characteristic of AGN. Here, we summarise our current understanding of the X-ray and optical continuum variability of radioquiet AGN and the relation between the two bands. We demonstrate the strong connection between the X-ray variability properties of AGN and the variability of stellar-mass black hole candidates on much shorter time-scale...
متن کاملThe ROSAT Deep Survey III. Optical spectral properties of X–ray sources in the Lockman Hole
The ROSAT Deep Survey in the Lockman Hole contains a complete sample of 50 X-ray sources with fluxes in the 0.5-2 keV band larger than 5.5 · 10 erg cm s. Previous work has provided optical identification of 46 of the 50 X-ray sources; over 75 % of the sources are AGNs (Schmidt et al. 1998). We present now the atlas of optical finding charts and the full description of the spectra, including emi...
متن کاملX-ray iron line reverberation from black hole accretion disks
The relativistically broad X-ray iron line seen in many AGN spectra is thought to originate from the central regions of the putative black hole accretion disk. Both the line profile and strength will vary in response to rapid variability of the primary X-ray continuum source. The temporal response of the line contains information on the accretion disk structure, the X-ray source geometry, and t...
متن کاملX-ray Reflections on Agn
X-ray reflection generates much of the spectral complexity in the X-ray spectra of AGN. It is argued that strong relativistic blurring of the reflection spectrum should commonly be expected from objects accreting at a high Eddington rate. The good agreement found between the local density in massive black holes and the energy density in quasar and AGN light requires that the accretion which bui...
متن کاملX-ray transient galaxies and AGN
X-ray transience is the most extreme form of variability observed in AGN or normal in-active galaxies. While factors of 2-3 on timescales of days to years are quite commen among AGN, X-ray transients appear only once and vanish from the X-ray sky years later. The ROSAT All-Sky Survey was the tool to discover these sources. X-ray transience in AGN or galaxies can be caused by dramatic changes in...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2008