X-ray Variability of Blazars

Abstract

Critical progress in our understanding of high energy emission from AGN has been determined in the last 10 years by X-ray monitoring campaigns with many space missions, notably ROSAT, ASCA, RXTE, BeppoSAX, and XMM, often in conjunction with observations at other frequencies. The emphasis of the present review is on recent findings about X-ray variability of blazars. Among AGN, these exhibit the largest amplitude variations of the X-ray emission, often well correlated with variations at higher energies (GeV and TeV radiation). The accurate sampling of the X-ray spectra over more than three decades in energy, made possible by the wide energy range of BeppoSAX, has also shown strong spectral variability in blazar active states, suggesting extreme electron energies and leading to the identification of a class of `extreme synchrotron' sources.

Review talk at the Elizabeth and Frederick White Workshop "AGN Variability across the Electromagnetic Spectrum", held in Sydney, 25 - 29 June 2001; Publications of the Astronomical Society of Australia, 19, in press

References in corpus (7)

• Hard X-ray properties of blazars
• Extreme synchrotron BL Lac objects
• An evolutionary scenario for blazar unification
• Multi-Epoch Multiwavelength Spectra and Models for Blazar 3C~279
• Simultaneous X-Ray and TeV Gamma-Ray Observations of the TeV Blazar Markarian 421 during February and May 2000
• High Temporal Resolution XMM Monitoring of PKS 2155-304
• Spectral Energy Distributions of 3C 279 revisited: BeppoSAX observations and variability models

Cited by in corpus (11)

• Month-Timescale Optical Variability in the M87 Jet
• XMM-Newton timing mode observations of Mrk 421
• XMM-Newton view of PKS 2155-304: hardness ratio and cross-correlation analysis of EPIC pn observations
• Synthetic X-ray light curves of BL Lacs from relativistic hydrodynamic simulations
• Multiwavelength Observations of the BL Lacertae Object PKS 2155-304 with XMM-Newton
• Evolution of the synchrotron and inverse Compton emissions of the low energy peaked BL Lac object S5 0716+714
• A Search for Intraday Variability in the Blazar PKS 2005-489
• Rapid X-ray Variability in Mkn 421 during a Multiwavelength Campaign
• Long-term hard X-ray variability properties of Swift-BAT blazars
• An XMM-Newton look at the strongly variable radio-weak BL Lac Fermi J1544-0639
• Characterizing the Variable X-ray and UV-Optical Flux Behavior of Blazars