1932

Abstract

This article reviews the recent observational results regarding γ-ray emission from active galaxies. The most numerous discrete extragalactic γ-ray sources are AGNs dominated by relativistic jets pointing in our direction (commonly known as blazars), and they are the main subject of the review. They are detected in all observable energy bands and are highly variable. The advent of the sensitive γ-ray observations, afforded by the launch and continuing operation of the and the AGILE Gamma-ray Imaging Detector, as well as by the deployment of current-generation Air Cerenkov Telescope arrays such as VERITAS, MAGIC, and HESS-II, continually provides sensitive γ-ray data over the energy range of ∼100 MeV to multi-TeV. Importantly, it has motivated simultaneous, monitoring observations in other bands, resulting in unprecedented time-resolved broadband spectral coverage. After an introduction, in Sections 3, 4, and 5, we cover the current status and highlights of γ-ray observations with (mainly) but also AGILE and put those in the context of broadband spectra in Section 6. We discuss the radiation processes operating in blazars in Section 7, and we discuss the content of their jets and the constraints on the location of the energy dissipation regions in, respectively, Sections 8 and 9. Section 10 covers the current ideas for particle acceleration processes in jets, and Section 11 discusses the coupling of the jet to the accretion disk in the host galaxy. Finally, Sections 12, 13, and 14 cover, respectively, the contribution of blazars to the diffuse γ-ray background, the utility of blazars to study the extragalactic background light, and the insight they provide for study of populations of supermassive black holes early in the history of the Universe.

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2016-09-19
2025-04-28
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Literature Cited

  1. Abdo A, Ackermann M, Agudo I. et al. 2010a. Ap. J. 716:30 [Google Scholar]
  2. Abdo A, Ackermann M, Ajello M. et al. 2009. Ap. J. 699:817 [Google Scholar]
  3. Abdo A, Ackermann M, Ajello M. et al. 2010b. Ap. J. 715:429 [Google Scholar]
  4. Abdo A, Ackermann M, Ajello M. et al. 2010c. Ap. J. 722:520 [Google Scholar]
  5. Abdo A, Ackermann M, Ajello M. et al. 2010d. Nature 463:919 [Google Scholar]
  6. Abdo A, Ackermann M, Ajello M. et al. 2011. Ap. J. 733:L26 [Google Scholar]
  7. Abeysekara AU, Alfaro R, Alvarez C. et al. 2015a. Astropart. Phys. 62:125 [Google Scholar]
  8. Abeysekara A, Archambault S, Archer A. et al. 2015b. Ap. J. Lett. 815:L22 [Google Scholar]
  9. Abramowski A, Acero F, Aharonian F. et al. 2013. Astron. Astrophys. 554:A107 [Google Scholar]
  10. Acero F, Ackermann M, Ajello M. et al. 2015. Ap. J. (Suppl.) 218:23 [Google Scholar]
  11. Ackermann M, Ajello M, Albert A. et al. 2015a. Ap. J. Lett. 813:L41 [Google Scholar]
  12. Ackermann M, Ajello M, Allafort A. et al. 2011. Ap. J. 743:171 [Google Scholar]
  13. Ackermann M, Ajello M, Allafort A. et al. 2012a. Ap. J. 755:164 [Google Scholar]
  14. Ackermann M, Ajello M, Allafort A. et al. 2012b. Ap. J. 747:104 [Google Scholar]
  15. Ackermann M, Ajello M, Allafort A. et al. 2013. Ap. J. 765:54 [Google Scholar]
  16. Ackermann M, Ajello M, Atwood WB. et al. 2015b. Ap. J. 810:14 [Google Scholar]
  17. Aharonian F. 2000. New Astronomy 5:377 [Google Scholar]
  18. Aharonian F, Akhperjanian AG, Bazer-Bachi AR. et al. 2007. Ap. J. Lett. 664:L71 [Google Scholar]
  19. Ahnen ML, Anslodi S, Antonelli LA. et al. 2015. Ap. J. Lett. 815:L23 [Google Scholar]
  20. Ajello M, Dominguez A, Gasparini D, Cutini S. 2015b. Proc. 5th Fermi Symp., Nogoya, Japan, Oct. 20–24, 2014 eConf C14102.1 [Google Scholar]
  21. Ajello M, Gasparrini D, Sánchez-Conde M. et al. 2015a. Ap. J. Lett. 800:L27 [Google Scholar]
  22. Albert J, Aliu E, Anderhub H. et al. 2008. Science 320:1752 [Google Scholar]
  23. Aleksić J, Anslodi S, Antonelli LA. et al. 2015a. Astropart. Phys. 72:61 [Google Scholar]
  24. Aleksić J, Anslodi S, Antonelli LA. et al. 2015b. Astropart. Phys. 72:76 [Google Scholar]
  25. Aleksić J, Antonelli LA, Antoranz P. et al. 2011. Ap. J. Lett. 730:L8 [Google Scholar]
  26. Amato E, Arons J. 2006. Ap. J. 653:325 [Google Scholar]
  27. Archambault S, Archer A, Beilicke M. et al. 2015. Ap. J. 808:110 [Google Scholar]
  28. Atwood WB, Abdo A, Ackermann M. et al. 2009. Ap. J. 697:1071 [Google Scholar]
  29. Baloković M, Paneque D, Madejski G. et al. 2016. Ap. J. 819:156 [Google Scholar]
  30. Barbiellini G, Tavani M, Argan A. et al. 2001. Gamma 2001: Gamma-Ray Astrophys. 2001 S Ritz, N Gehrels, CR Schader AIP Conf. Proc. 587774 Melville, NY: AIP [Google Scholar]
  31. Barth A, Ho L, Sargent W. 2002. Ap. J. Lett. 566:L13 [Google Scholar]
  32. Barth A, Ho L, Sargent W. 2003. Active Galactic Nuclei: From Central Engine Host Galaxy S Collin, F Combes, I Shlosman ASP Conf. Ser. 290601 San Francisco: ASP [Google Scholar]
  33. Begelman MC, Blandford R, Rees M. 1984. Rev. Mod. Phys. 56:255 [Google Scholar]
  34. Begelman MC, Fabian A, Rees M. 2008. MNRAS 384:L19 [Google Scholar]
  35. Begelman MC, Sikora M. 1987. Ap. J. 322:650 [Google Scholar]
  36. Bell A. 1978a. MNRAS 182:147 [Google Scholar]
  37. Bell A. 1978b. MNRAS 182:443 [Google Scholar]
  38. Blandford R, East W, Nalewajko K, Yuan Y, Zrake J. 2015. Pubs. Acad. Mex. Cienc. Submitted. arXiv:1511.07515 [Google Scholar]
  39. Blandford R, Königl A. 1979. Ap. J. 232:34 [Google Scholar]
  40. Blandford R, Ostriker J. 1978. Ap. J. Lett. 221:L29 [Google Scholar]
  41. Blandford R, Znajek R. 1977. MNRAS 179:433 [Google Scholar]
  42. Blinov D, Pavlidou V, Papadakis I. et al. 2015. MNRAS 453:1669 [Google Scholar]
  43. Blumenthal G, Gould R. 1970. Rev. Mod. Phys. 42:237 [Google Scholar]
  44. Bonning E, Urry CM, Bailyn C. et al. 2012. Ap. J. 756:13 [Google Scholar]
  45. Böttcher M, Chiang J. 2002. Ap. J. 581:127 [Google Scholar]
  46. Böttcher M, Reimer A, Sweeney K, Prakash A. 2013. Ap. J. 768:54 [Google Scholar]
  47. Casandjian J-M, Grenier I. 2008. Astron. Astrophys. 489:849 [Google Scholar]
  48. Chadwick PM, Lyons K, McComb TJL. et al. 1999. Ap. J. 513:161 [Google Scholar]
  49. Choi J-H, Schlosman I, Begelman MC. 2015. MNRAS 450:4411 [Google Scholar]
  50. Coppi P, Aharonian F. 1997. Ap. J. Lett. 487:L9 [Google Scholar]
  51. Dermer C, Schlickheiser R, Mastichiadis A. 1992. Astron. Astrophys. 256:L27 [Google Scholar]
  52. Fermi E. 1949. Phys. Rev. 75:1169 [Google Scholar]
  53. Finke JD, Reyes LC, Georganopoulos M. et al. 2015. Ap. J. 814:20 [Google Scholar]
  54. Foschini L, Berton M, Caccianiga A. et al. 2015. Astron. Astrophys. 575:13 [Google Scholar]
  55. Fossati G, Maraschi L, Celotti A, Comastri A, Ghisellini G. 1998. MNRAS 299:433 [Google Scholar]
  56. Furniss A, Noda K, Boggs S. et al. 2015. Ap. J. 812:65 [Google Scholar]
  57. Furniss A, Williams DA, Danforth C. et al. 2013. Ap. J. Lett. 768:L31 [Google Scholar]
  58. Ghisellini G. 2011. 5th Texas Symp. Relativ. Astrophys. (Texas 2010) FA Aharonian, W Hofmann, FM Rieger AIP Conf. Proc. 1381180 Melville, NY: AIP [Google Scholar]
  59. Ghisellini G. 2012. MNRAS 424:L26 [Google Scholar]
  60. Ghisellini G, Celotti A, Costamante L. 2002. Astron. Astrophys. 386:833 [Google Scholar]
  61. Ghisellini G, Maraschi L, Treves A. 1985. Astron. Astrophys. 146:204 [Google Scholar]
  62. Ghisellini G, Nardini M, Tagliaferri G. et al. 2013. MNRAS 428:1449 [Google Scholar]
  63. Ghisellini G, Tavecchio F. 2009. MNRAS 397:985 [Google Scholar]
  64. Ghisellini G, Tavecchio F, Foschini L, Ghirlanda G. 2011. MNRAS 414:2674 [Google Scholar]
  65. Ghisellini G, Tavecchio F, Foschini L, Ghirlanda G, Maraschi L. 2010. MNRAS 402:497 [Google Scholar]
  66. Ghisellini G, Tavecchio F, Maraschi L, Celotti A, Sbarrato T. 2014. Nature 515:376 [Google Scholar]
  67. Giommi P, Padovani P, Polenta G. et al. 2012. MNRAS 420:2899 [Google Scholar]
  68. Grandi P. 2012. Int. J. Mod. Phys. Conf. Ser. 8:25 [Google Scholar]
  69. Gubbay J, Legg A, Robertson D. et al. 1969. Nature 224:1094 [Google Scholar]
  70. Guo F, Liu Y-H, Daughton W, Li H. 2015. Ap. J. 806:167 [Google Scholar]
  71. Harrison FA, Craig WW, Christensen FE. et al. 2013. Ap. J. 770:103 [Google Scholar]
  72. Hartman RC, Bertsch DL, Bloom SB. et al. 1999. Ap. J. Suppl. 123:79 [Google Scholar]
  73. Hayashida M, Madejski G, Nalewajko K. et al. 2012. Ap. J. 754:114 [Google Scholar]
  74. Hayashida M, Nalewajko K, Madejski G. et al. 2015. Ap. J. 807:79 [Google Scholar]
  75. Holder J, Aliu E, Arlen T. et al. 2011. Presented at 32nd Int. Cosmic Ray Conf, Beijing, China. arxiv:1111.1225
  76. Holder J, Atkins RW, Badran HM. et al. 2006. Astropart. Phys. 25:391 [Google Scholar]
  77. Hoshino M, Arons J, Gallant YA, Langdon AB. 1992. Ap. J. 390:454 [Google Scholar]
  78. Inoue Y. 2011. Ap. J. 733:66 [Google Scholar]
  79. Jelley J. 1966. Nature 211:472 [Google Scholar]
  80. Johnson WN, Kinzer RL, Kurfess JD. et al. 1993. Ap. J. Suppl. 86:693 [Google Scholar]
  81. Jorstad S, Marscher A, Lister M. et al. 2005. Astron. J. 130:1418 [Google Scholar]
  82. Katarzynski K, Ghisellini G, Mastichiadis A, Tavecchio F, Maraschi L. 2006. Astron. Astrophys. 453:47 [Google Scholar]
  83. Katarzynski K, Ghisellini G, Tavecchio F. et al. 2005. Astron. Astrophys. 433:479 [Google Scholar]
  84. Kellermann K, Pauliny-Toth I. 1969. Ap. J. Lett. 155:L71 [Google Scholar]
  85. Königl A. 1981. Ap. J. 243:700 [Google Scholar]
  86. Kormendy J, Ho L. 2013. Annu. Rev. Astron. Astrophys. 51:511 [Google Scholar]
  87. Kraushaar W, Clark G, Garmire G. et al. 1972. Ap. J. 177:341 [Google Scholar]
  88. Larsson S. 2012. J. Phys. Conf. Ser. 355:2029 [Google Scholar]
  89. Lister ML, Aller MF, Aller HD. et al. 2013. Astron. J. 146:120 [Google Scholar]
  90. Madsen K, Fuerst F, Walton D. et al. 2015. Ap. J. 812:14 [Google Scholar]
  91. Mannheim K, Biermann PL. 1992. Astron. Astrophys. 253:L21 [Google Scholar]
  92. Marscher A. 2014. Ap. J. 780:87 [Google Scholar]
  93. Marscher A, Gear W. 1985. Ap. J. 298:114 [Google Scholar]
  94. Marscher AP, Jorstad SG, D'Arcangelo FD. et al. 2008. Nature 452:966 [Google Scholar]
  95. Marscher AP, Marshall FE, Mushotzky RF. et al. 1979. Ap. J. 233:498 [Google Scholar]
  96. Massaro F, Thompson D, Ferrara E. 2016. Astron. Astrophys. Rev. 24:2 [Google Scholar]
  97. McKinney J, Blandford R. 2009. MNRAS 394:L126 [Google Scholar]
  98. McKinney J, Tchekhovskoy A, Blandford R. 2012. MNRAS 423:3083 [Google Scholar]
  99. Moderski R, Sikora M, Blazejowski M. 2003. Astron. Astrophys. 406:855 [Google Scholar]
  100. Nalewajko K, Begelman MC, Sikora M. 2014. Ap. J. 789:161 [Google Scholar]
  101. Nalewajko K, Giannios D, Begelman MC, Uzdensky D, Sikora M. 2011. MNRAS 413:333 [Google Scholar]
  102. Nalewajko K, Uzdensky D, Cerutti B, Werner GR, Begelman MC. 2015. Ap. J. 815:101 [Google Scholar]
  103. Narayan R, Kumar P. 2009. MNRAS 394:L117 [Google Scholar]
  104. Narayan R, Piran T. 2012. MNRAS 420:604 [Google Scholar]
  105. Narayan R, Yi I. 1994. Ap. J. Lett. 428:L13 [Google Scholar]
  106. Narayan R, Yi I. 1995. Ap. J. 452:710 [Google Scholar]
  107. Neronov A, Semikoz D. 2006. JETP Lett. 85:473 [Google Scholar]
  108. Neronov A, Semikoz D. 2009. Phys. Rev. D 80:123012 [Google Scholar]
  109. Padovani P, Urry CM. 1992. Ap. J. 387:449 [Google Scholar]
  110. Poutanen J, Stern B. 2010. Ap. J. Lett. 717:L118 [Google Scholar]
  111. Punch M, Akerlof CW, Cawley MF. et al. 1992. Nature 358:477 [Google Scholar]
  112. Punsly B, Igumenshchev I, Hirose S. 2009. Ap. J. 687:162 [Google Scholar]
  113. Quinn J, Akerlof CW, Biller S. et al. 1996. Ap. J. 456:83 [Google Scholar]
  114. Rando R, Buson S. 2015. Riv. Nuovo Cim. 38:209 [Google Scholar]
  115. Rees M. 1966. Nature 211:468 [Google Scholar]
  116. Romani R, Sowards-Emmerd D, Greenhill L, Michelson P. 2004. Ap. J. Lett. 610:L9 [Google Scholar]
  117. Sanders D, Phinney ES, Neugerbauer G, Soifer BT, Matthews K. 1989. Ap. J. 347:29 [Google Scholar]
  118. Sbarrato T, Ghisellini G, Nardini M. et al. 2012. MNRAS 426:L91 [Google Scholar]
  119. Sbarrato T, Tagliaferri G, Ghisellini G. et al. 2013. Ap. J. 777:147 [Google Scholar]
  120. Schoenfelder V, Aarts H, Bennett K. et al. 1993. Ap. J. Suppl. 86:657 [Google Scholar]
  121. Shaw M, Romani R, Cotter G. et al. 2012. Ap. J. 748:49 [Google Scholar]
  122. Shaw M, Romani R, Cotter G. et al. 2013. Ap. J. 764:135 [Google Scholar]
  123. Sikora M. 2011. Jets at All Scales, IAU Symp. S275 G Romero, R Sunyaev, T Bellon 659 Cambridge, UK: Cambridge Univ. Press [Google Scholar]
  124. Sikora M, Begelman MC, Madejski G, Lasota J-P. 2005. Ap. J. 625:72 [Google Scholar]
  125. Sikora M, Begelman MC, Rees M. 1994. Ap. J. 421:153 [Google Scholar]
  126. Sikora M, Madejski G. 2000. Ap. J. 534:109 [Google Scholar]
  127. Sikora M, Rutkowski M, Begelman MC. 2016. MNRAS 457:1352 [Google Scholar]
  128. Sikora M, Stawarz L, Moderski R, Nalewajko K, Madejski G. 2009. Ap. J. 704:38 [Google Scholar]
  129. Sillanpaa A, Haarala S, Valtonen M, Sundelius B, Byrd G. 1988. Ap. J. 325:628 [Google Scholar]
  130. Sironi L, Petropoulu D, Giannios D. 2015. MNRAS 450:183 [Google Scholar]
  131. Sironi L, Spitkovsky A. 2011. Ap. J. 726:75 [Google Scholar]
  132. Sironi L, Spitkovsky A. 2014. Ap. J. Lett. 783:L21 [Google Scholar]
  133. Sitarek J, Becerra-Gonzlez J, Dominis-Prester D. et al. 2015. Proc. 34th ICRS, Hague, The Netherlands, Jul. 30–Aug. 6. arXiv:1508.04580 [Google Scholar]
  134. Soldi S, Beckmann V, Türler M. 2009. Proc. 2009 Fermi Symp., Washington, DC, Nov. 2–5 eConf C09112. arXiv:0912.2266 [Google Scholar]
  135. Spada M, Ghisellini G, Lazzati D, Celotti A. 2001. MNRAS 325:1559 [Google Scholar]
  136. Stawarz L, Petrosian V. 2008. Ap. J. 681:1725 [Google Scholar]
  137. Stein W, O`Dell S, Strittmatter P. 1976. Annu. Rev. Astron. Astrophys. 14:173 [Google Scholar]
  138. Swanenburg B, Bennet K, Bignami GF. et al. 1981. Ap. J. Lett. 243:L69 [Google Scholar]
  139. Swanenburg B, Hermsen W, Bennett K. et al. 1978. Nature 275:298 [Google Scholar]
  140. Tavani M, Barbiellini G, Argan A. et al. 2009. Astron. Astrophys. 502:995 [Google Scholar]
  141. Tavecchio F, Ghisellini G, Bonnoli G, Foschini L. 2011. MNRAS 414:3566 [Google Scholar]
  142. Tchekhovskoy A, Narayan R, McKinney J. 2011. MNRAS 418:L79 [Google Scholar]
  143. The Fermi LAT Collab., Ackermann M, Ajello M, Albert A et al. 2015. J. Cosmol. Astropart. Phys. 9:8 [Google Scholar]
  144. Thompson D, Bertsch DL, Fichtel CE. et al. 1993. Ap. J. Suppl. 86:629 [Google Scholar]
  145. Tramacere A, Giommi P, Perri M, Verrecchia F, Tosti G. 2009. Astron. Astrophys. 501:879 [Google Scholar]
  146. Tramacere A, Massaro E, Taylor A. 2011. Ap. J. 739:66 [Google Scholar]
  147. Ushio M, Stawarz L, Takahashi T. et al. 2010. Ap. J. 724:1509 [Google Scholar]
  148. Ushio M, Tanaka T, Madejski G. et al. 2009. Ap. J. 699:1964 [Google Scholar]
  149. Vermeulen R, Ogle PM, Tran HD. et al. 1995. Ap. J. Lett. 452:L5 [Google Scholar]
  150. Weekes T, Turver K. 1977. ESA Recent Advances in Gamma-ray Astronomy279 [Google Scholar]
  151. Wehrle A, Grupe D, Jorstad SG. et al. 2016. Ap. J. 816:53 [Google Scholar]
  152. Williams R, Pogge R, Mathur S. 2002. Astron. J. 124:30429 [Google Scholar]
  153. Yuan F, Narayan R. 2014. Annu. Rev. Astron. Astrophys. 52:529 [Google Scholar]
  154. Zaborov D, Romoli C, Taylor AM. et al. 2015. Proc. 34th ICRS, Hague, The Netherlands, Jul. 30–Aug. 6. arXiv:1509.06509 [Google Scholar]
  155. Zdziarski A, Böttcher M. 2015. MNRAS 450:21 [Google Scholar]
  156. Zhang H, Chen X, Böttcher M, Guo F, Li H. 2015. Ap. J. 804:58 [Google Scholar]
  157. Zrake J, East W. 2016. Ap. J. 817:89 [Google Scholar]
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