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X-ray Variability of Blazars

Published online by Cambridge University Press:  05 March 2013

Elena Pian*
Affiliation:
INAF, Astronomical Observatory of Trieste, Via G. B. Tiepolo 11, I-34131 Trieste, Italy; [email protected]
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Abstract

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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.

Type
Research Article
Copyright
Copyright © Astronomical Society of Australia 2002

References

Aharonian, F. 2000, NewA, 5, 377 CrossRefGoogle Scholar
Aharonian, F., et al. 2001, ApJ, 546, 898 Google Scholar
Ballo, L., et al. 2002, ApJ, 567, in press (astro-ph/0111499)Google Scholar
Boettcher, M., & Dermer, C. D. 2002, ApJ, 564, 86 CrossRefGoogle Scholar
Brinkmann, W., Gliozzi, M., Urry, C. M., Maraschi, L., & Sambruna, R. 2000, A&A, 362, 105 Google Scholar
Brinkmann, W., et al. 2001, A&A, 365, L162 Google Scholar
Catanese, M., et al. 1997, ApJ, 487, L143 CrossRefGoogle Scholar
Catanese, M., & Sambruna, R. M. 2000, ApJ, 534, L39 Google Scholar
Chadwick, P. M., et al. 1999, ApJ, 513, 161 Google Scholar
Chiaberge, M., & Ghisellini, G. 1999, MNRAS, 306, 551 Google Scholar
Chiappetti, L., et al. 1999, ApJ, 521, 552 Google Scholar
Costamante, L., et al. 2001, A&A, 371, 512 Google Scholar
Donato, D., Ghisellini, G., Tagliaferri, G., & Fossati, G. 2001, A&A, 375, 739 Google Scholar
Donea, A.-C., & Protheroe, R. J. 2002, PASA, 19, 39 Google Scholar
Edelson, R. A., et al. 1995, ApJ, 438, 120 Google Scholar
Edelson, R. A., & Nandra, K. 1999, ApJ, 514, 682 CrossRefGoogle Scholar
Edelson, R. A., Griffiths, G., Markowitz, A., Sembay, S., Turner, M. J. L., & Warwick, R. 2001, ApJ, 554, 274 Google Scholar
Fossati, G., Maraschi, L., Celotti, A., Comastri, A., & Ghisellini, G. 1998, MNRAS, 299, 433 CrossRefGoogle Scholar
Fossati, G., et al. 2000a, ApJ, 541, 153 Google Scholar
Fossati, G., et al. 2000b, ApJ, 541, 166 Google Scholar
Fossati, G. 2001, Proc. of “X-ray Astronomy 2000” (Palermo, September 2000), Eds. R. Giacconi, L. Stella, and S. Serio, ASP Conf. Ser., in pressGoogle Scholar
Georganopoulos, M., & Marscher, A. P. 1998, ApJ, 506, L11 Google Scholar
Ghisellini, G., Celotti, A., Fossati, G., Maraschi, L., & Comastri, A. 1998, MNRAS, 301, 451 CrossRefGoogle Scholar
Ghisellini, G., et al. 1999, A&A, 348, 63 Google Scholar
Giommi, P., et al. 1998, A&A, 333, L5 Google Scholar
Giommi, P., et al. 1999, A&A, 351, 59 Google Scholar
Giommi, P., Padovani, P., & Perlman, E. 2000, MNRAS, 317, 743 Google Scholar
Guainazzi, M., Vacanti, G., Malizia, A., O'Flaherty, K. S., Palazzi, E., & Parmar, A. N. 1999, A&A, 342, 124 Google Scholar
Hartman, R. C., et al. 2001, ApJ, 553, 683 Google Scholar
Kataoka, J., et al. 1999, ApJ, 514, 138 Google Scholar
Kataoka, J., et al. 2000, ApJ, 528, 243 Google Scholar
Kirk, J. G., Rieger, F. M., & Mastichiadis, A. 1998, A&A, 333, 452 Google Scholar
Krawczynski, H., Coppi, P. S., Maccarone, T., & Aharonian, F. A. 2000, A&A, 353, 97 Google Scholar
Krawczynski, H., et al. 2001, ApJ, 559, 187 Google Scholar
Lamer, G., & Wagner, S. J. 1998, A&A, 331, L13 Google Scholar
Lawson, A. J., McHardy, I. M., & Marscher, A. P. 1999, MNRAS, 306, 247 Google Scholar
Malizia, A., et al. 2000, MNRAS, 312, 123 CrossRefGoogle Scholar
Mannheim, K. 1998, Science, 279, 684 Google Scholar
Maraschi, L., et al. 1999, ApJ, 526, L81 Google Scholar
Maraschi, L., Chiappetti, L., Fossati, G., Pian, E., & Tavecchio, F. 2000, AdSpR, 25, 713 Google Scholar
Maraschi, L., & Tavecchio, F. 2001, Proc. of “X-ray Astronomy 2000” (Palermo, September 2000), Eds. R. Giacconi, L. Stella, and S. Serio, ASP Conf. Ser., in press (astro-ph/0107566)Google Scholar
Maraschi, L. 2001, in Relativistic Astrophysics: 20th Texas Symposium, AIP Conf. Proc. 586, Eds. J. C. Wheeler and H. Martel, p. 409 Google Scholar
McHardy, I. 1999, in BL Lac Phenomenon, ASP Conf. Ser., Vol. 159, Eds. L. O. Takalo and A. Sillanpää, p. 155 Google Scholar
Padovani, P., & Giommi, P. 1995, ApJ, 444, 567 Google Scholar
Perlman, E. S., Madejski, G., Stocke, J. T., & Rector, T. A. 1999, ApJ, 523, L11 Google Scholar
Petry, D., et al. 2000, ApJ, 536, 742 Google Scholar
Pian, E., et al. 1998, ApJ, 492, L17 CrossRefGoogle Scholar
Rachen, J. P. 2000, astro-ph/0010289Google Scholar
Ravasio, M., et al. 2002, A&A, in press (astro-ph/0201307)Google Scholar
Sambruna, R. M., et al. 1997, ApJ, 474, 639 Google Scholar
Sambruna, R. M. 1999, Frascati Workshop 1999, May 24–29, 1999, Vulcano, Italy, MEMSAIt, (astro-ph/9912060)Google Scholar
Sambruna, R. M., et al. 2000, ApJ, 538, 127 Google Scholar
Sembay, S., et al. 1993, ApJ, 404, 112 CrossRefGoogle Scholar
Tagliaferri, G., et al. 2000, A&A, 354, 431 Google Scholar
Tagliaferri, G., et al. 2001, A&A, 368, 38 Google Scholar
Takahashi, T., et al. 1996, ApJ, 470, L89 Google Scholar
Takahashi, T., Madejski, G., & Kubo, H. 1999, APh, 11, 177 Google Scholar
Takahashi, T., et al. 2000, ApJ, 542, L105 Google Scholar
Tanihata, C., et al. 2000, ApJ, 543, 124 Google Scholar
Tavecchio, F., Maraschi, L., & Ghisellini, G. 1998, ApJ, 509, 608 Google Scholar
Tavecchio, F., et al. 2001, ApJ, 554, 725 Google Scholar
Treves, A., et al. 1999, Astronomische Nachrichten 320, n. 4, p. 317 Google Scholar
Ulrich, M.-H., Maraschi, L., & Urry, C. M. 1997, ARA&A, 35, 445 Google Scholar
Urry, C. M., et al. 1993, ApJ, 411, 614 Google Scholar
Urry, C. M., et al. 1997, ApJ, 486, 799 Google Scholar
Urry, C. M. 1999, APh, 11, 159 Google Scholar
Vestrand, W. T., & Sreekumar, P. 1999, APh, 11, 197 Google Scholar
Wehrle, A. E., et al. 1998, ApJ, 497, 178 Google Scholar
Zhang, Y. H., et al. 1999, ApJ, 527, 719 Google Scholar