Jets in gamma-bright AGN: Constraints on reprocessing mechanisms

  • Stefan J. Wagner
Jets from Agn, The Core
First Online:
Part of the Lecture Notes in Physics book series (LNP, volume 471)

Abstract

Several dozen active galaxies have been detected by instruments sensitive to hard gamma-ray radiation. All of these objects are radio-loud AGN and share several other characteristics in the low-energy part of their spectra. The gamma-ray emission varies on time-scales from days to years and is characterized by a power-law spectrum. In order to determine the broad-band energy distributions of these objects, a series of simultaneous multifrequency campaigns has been arranged. Apart from providing the low-frequency properties during those states when the sources were bright enough in the gamma-ray range to be detected, such campaigns provide clues to the degree of correlation between variations in different energy regimes. Several cases were found which indicate that the optically thin part of the synchrotron radiation is closely connected to the gamma-ray range. This sets constraints on the reprocessing mechanisms responsible for the gamma-ray emission.

In addition to studies in the GeV regime, ground-based Cherenkov telescopes allow investigations of the gamma-ray properties in the TeV regime. One such source, the BL Lac object Mrk 421 has been found to emit variable TeV radiation which might be related to the variable emission seen in the optical regime.

Keywords

Optical Flare Seed Photon Egret Source Quiescent Level Unidentified Egret Source 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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References

  1. Aller, M. et al., 1996, in IAU Symp. 175, Extragalactic Radio Sources, C. Fanti et al. (Eds.), Kluwer, in pressGoogle Scholar
  2. Buckley J., Quinn J., Weekes T., Catanese M., Carter-Lewis D. A., et al., 1995, IAUC 6167Google Scholar
  3. Barthel, P.D., Conway, J.E., Myers, S.T., Pearson, T.J., and Readhead, A.C.S., 1995, ApJ 444, L21ADSCrossRefGoogle Scholar
  4. Bednarek, W. and Kirk, J.G., 1995, A&A 294, 366ADSGoogle Scholar
  5. Dermer C.D., Schlickeiser, R., and Mastichiadis A., 1992, A&A 256, L27ADSGoogle Scholar
  6. Eckart, A., Witzel, A., Biermann P.L., Johnston, K.J., Simon, R., Schalinski, C.J., and Kühr, H.: 1987, A&A Supp. 67, 121ADSGoogle Scholar
  7. Hartman R.C., Bertsch D.L., Dingus B.L., Fichtel C.E., Hunter S.D., et al., 1993, ApJ Lett. 407, 41ADSCrossRefGoogle Scholar
  8. Hartman R.C. et al., 1996, ApJ, in pressGoogle Scholar
  9. Henri, G., Pelletier, G., and Roland, J., 1993, ApJ 404, L41ADSCrossRefGoogle Scholar
  10. Heidt J. and Wagner, S., 1996, A&A 305, 42ADSGoogle Scholar
  11. Hunter, S.D., Bertsch D.L., Dingus B.L., Fichtel C.E., Hartman R.C., et al., 1993, ApJ 409, 134ADSCrossRefGoogle Scholar
  12. Kerrick, A.D., Akerlof, C.W., Biller, S.D., Buckley, J.H., Cawley, M.F., et al., 1995, ApJ Lett. 438, 59ADSCrossRefGoogle Scholar
  13. Kniffen D.A., Bertsch D.L., Fichtel C.E., Hartman R.C., Hunter S.D., et al., 1993, ApJ 411, 133ADSCrossRefGoogle Scholar
  14. Kundt, W. and Gopal-Krishna, 1980, Nature 288, 149ADSCrossRefGoogle Scholar
  15. Mannheim, K., and Biermann, P.L., 1992, A&A 253, L21ADSGoogle Scholar
  16. Maraschi, L., Ghisellini, G., and Celotti, A., 1992, ApJ 397, L5ADSCrossRefGoogle Scholar
  17. Marscher, A.P., 1980, ApJ 235, 3865CrossRefGoogle Scholar
  18. Marscher, A., 1996, in Quasars and AGN: High Resolution Radio Imaging, M. Cohen and K. Kellerman (Eds.), Proc. Nat. Acad. Sci., in pressGoogle Scholar
  19. Mattox J.R., Bertsch D.L., Chiang J., Dingus B.L., Fichtel C.E., et al., 1993, ApJ 410, 609ADSCrossRefGoogle Scholar
  20. Mattox, J.R., Wagner, S.J., McGlynn, T.A., Malkan, M., Schachter, J.F., Sreekumar, P., 1995, IAUC, 6179, 6181ADSGoogle Scholar
  21. McBreen, B., 1979, A&A 71, L19ADSGoogle Scholar
  22. McGlynn T.A., Mattox J.R., Vestrand W.T., Dingus B.L., Bertsch D.L., et al., 1994, IAUC 6061Google Scholar
  23. McGlynn T.A., Hartman R.C., Aller M.F., Filippenko A.V., Marscher A.P, et al., 1996, ApJ, submittedGoogle Scholar
  24. Mukherjee R., Aller H.D., Aller M.F., Bertsch D.L., Collmar W, et al., 1995, ApJ 445, 189ADSCrossRefGoogle Scholar
  25. Mukherjee R. et al., 1996, ApJ, in pressGoogle Scholar
  26. Reich, W., et al., 1993, A&A 273, 65ADSGoogle Scholar
  27. Schlickeiser, R., 1996, A&A Supp., in pressGoogle Scholar
  28. Sikora M., Begelman M.C., and Rees M.J., 1994, ApJ 421, 153ADSCrossRefGoogle Scholar
  29. Sol, H., Pelletier, G., and Asséo, E., 1989, MN 237, 411ADSGoogle Scholar
  30. Takahashi, T. et al., 1996, ApJ, in pressGoogle Scholar
  31. Thompson, D. et al., 1996, ApJ Supp., in pressGoogle Scholar
  32. Valtaoja, E. et al., 1996, A&A Supp., in pressGoogle Scholar
  33. von Linde J, Borgeest U., Schramm K.-J., Graser U., Heidt J. et al., 1993, A&A 267, L23ADSGoogle Scholar
  34. von Montigny C., Bertsch D.L., Chiang J., Dingus B.L., Esposito J.A., et al., 1995, ApJ 440, 525ADSCrossRefGoogle Scholar
  35. Wagner, S.J., 1996a, in 17th Texas Symposium on Relativistic Astrophysics, H. Böhringer et al. (Eds.), New York Acad. Sci., 759, p. 526Google Scholar
  36. Wagner, S.J., 1996b, A&A Supp., in pressGoogle Scholar
  37. Wagner S.J. and Witzel A., 1995, ARAA 33, 163ADSCrossRefGoogle Scholar
  38. Wagner, S.J., Sanchez-Pons, F., Quirrenbach, A., and Witzel, A., 1990, A&A 235, L1ADSGoogle Scholar
  39. Wagner, S.J., Camenzind M., Dreissigacker O., Borgeest U., Britzen S., et al., 1995a, A&A 298, 688ADSGoogle Scholar
  40. Wagner, S.J., Mattox, J.R., Hopp, U., Bock, H., Heidt, J., et al., 1995b, ApJ Lett., 454, L97ADSCrossRefGoogle Scholar
  41. Wagner, S.J., et al., 1996, ApJ, in pressGoogle Scholar
  42. Wehrle, A, et al., 1996, A&A Supp, in pressGoogle Scholar
  43. Zhang, Y.C. et al., 1994, ApJ 432, 91ADSCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 1996

Authors and Affiliations

  • Stefan J. Wagner
    • 1
  1. 1.LandessternwarteHeidelbergGermany

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