Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· References in the article
· SIMBAD Objects (40)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
X-Ray Variability of Active Galactic Nuclei in the Soft and Hard X-Ray Bands
Authors:
Chitnis, V. R.; Pendharkar, J. K.; Bose, D.; Agrawal, V. K.; Rao, A. R.; Misra, R.
Affiliation:
AA(Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005, India ), AB(Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034, India, and Physical Research Laboratory, Ahmedabad 380009, India ), AC(Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005, India ; Current address: Universidad Complutense, E-28040 Madrid, Spain.), AD(Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005, India ), AE(Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005, India ), AF(Inter-University Center for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007, India )
Publication:
The Astrophysical Journal, Volume 698, Issue 2, pp. 1207-1220 (2009). (ApJ Homepage)
Publication Date:
06/2009
Origin:
IOP
ApJ Keywords:
black hole physics, galaxies: active, galaxies: nuclei, galaxies: Seyfert, X-rays: galaxies
DOI:
10.1088/0004-637X/698/2/1207
Bibliographic Code:
2009ApJ...698.1207C

Abstract

We investigate the X-ray variability characteristics of hard X-ray-selected active galactic nuclei (AGNs)—based on Swift/Burst Alert Telescope—in the soft X-ray band using the Rossi X-ray Timing Explorer/All-Sky Monitor (RXTE/ASM) data. The uncertainties involved in the individual dwell measurements of the ASM are critically examined, and a method is developed to combine a large number of dwells with appropriate error propagation to derive long-duration flux measurements (greater than 10 days). We also provide a general prescription to estimate the errors in variability derived from rms values from unequally spaced data. Though the derived variability for individual sources is not of very high significance, we find that, in general, the soft X-ray variability is higher than that in hard X-rays, and the variability strengths decrease with energy for the diverse classes of AGNs. We also examine the strength of variability as a function of the break timescale in the power density spectrum (derived from the estimated mass and bolometric luminosity of the sources) and find that the data are consistent with the idea of higher variability at timescales longer than the break timescale.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints