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Radio core dominance of Fermi/LAT-detected AGNs

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We present a sample of 4388 AGNs with available radio core-dominance parameters—defined as the ratio of the core flux densities to the extended ones, R = Score/Sext.—which includes 630 Fermi-detected AGNs from the fourth source catalog (4FGL) of the Fermi Large Area Telescope (Fermi/LAT); the rest are non-Fermi-detected AGNs. In our sample, 584 blazars are Fermi-detected and 1310 are not. The sample also contains other subclasses, such as Seyferts, Fanaroff-Riley I/II galaxies, and normal galaxies. We investigate various properties of the Fermi-detected and non-Fermi-detected AGNs by using core-dominance parameters, capitalizing on a previous study which showed that R is a good indicator of beaming. We then calculate radio spectral indices for the whole sample, and adopt γ-ray-photon indices for the Fermi AGNs from the 4FGL catalog to discuss the properties of different subclasses. We obtain a relation between the core-dominance parameters and the radio spectral indices for both Fermi and non-Fermi sources, assuming a two-component model in the radio band. Our previous study ruled out the assumption that the core-dominance parameters and radio spectral indices are quite different for different AGN subclasses. This holds not only for Fermi sources but also for non-Fermi sources. In particular, R is, on average, greater for the former AGNs than for the latter. In this study, we enlarge our sample with available values of R to 4388 AGNs, and the obtained conclusions are consistent with our previous study. We assume that the same two-component model holds for the γ-ray band as for the radio band, and therefore, adopt the same relation between the core-dominance parameters and the γ-ray-photon indices for Fermi AGNs. Our fitting results indicate that the γ-ray emissions of Fermi blazars originate mainly from the jet, and therefore, we conclude that the Fermi blazars are beamed.

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  1. 1

    C. M. Urry, and P. Padovani, Publ. Astron. Soc. Pacific 107, 803 (1995).

  2. 2

    M. L. Lister, M. F. Aller, H. D. Aller, T. Hovatta, W. Max-Moerbeck, A. C. S. Readhead, J. L. Richards, and E. Ros, Astrophys. J. 810, L9 (2015), arXiv: 1507.05953.

  3. 3

    J. D. Linford, G. B. Taylor, R. W. Romani, S. E. Healey, J. F. Helmboldt, A. C. S. Readhead, R. Reeves, J. L. Richards, and G. Cotter, Astrophys. J. 726, 16 (2011), arXiv: 1010.5812.

  4. 4

    Z. Wu, D. Jiang, M. Gu, and L. Chen, Astron. Astrophys. 562, A64 (2014), arXiv: 1401.0652.

  5. 5

    M. L. Lister, M. H. Cohen, D. C. Homan, M. Kadler, K. I. Kellermann, Y. Y. Kovalev, E. Ros, T. Savolainen, and J. A. Zensus, Astron. J. 138, 1874 (2009), arXiv: 0909.5100.

  6. 6

    T. Savolainen, D. C. Homan, T. Hovatta, M. Kadler, Y. Y. Kovalev, M. L. Lister, E. Ros, and J. A. Zensus, Astron. Astrophys. 512, A24 (2010), arXiv: 0911.4924.

  7. 7

    A. B. Pushkarev, Y. Y. Kovalev, M. L. Lister, and T. Savolainen, Astron. Astrophys. 507, L33 (2009), arXiv: 0910.1813.

  8. 8

    Y. Y. Kovalev, Astrophys. J. 707, L56 (2009), arXiv: 0908.4152.

  9. 9

    B. G. Piner, A. B. Pushkarev, Y. Y. Kovalev, C. J. Marvin, J. G. Arenson, P. Charlot, A. L. Fey, A. Collioud, and P. A. Voitsik, Astrophys. J. 758, 84 (2012), arXiv: 1208.4399.

  10. 10

    A. B. Pushkarev, and Y. Y. Kovalev, Astron. Astrophys. 544, A34 (2012), arXiv: 1205.5559.

  11. 11

    J. D. Linford, G. B. Taylor, R. W. Romani, J. F. Helmboldt, A. C. S. Readhead, R. Reeves, and J. L. Richards, Astrophys. J. 744, 177 (2012), arXiv: 1111.4505.

  12. 12

    H. B. Xiao, J. H. Fan, J. H. Yang, Y. Liu, Y. H. Yuan, J. Tao, D. Costantin, Y. T. Zhang, Z. Y. Pei, L. X. Zhang, and W. X. Yang, Sci. China-Phys. Mech. Astron. 62, 129811 (2019), arXiv: 1902.10764.

  13. 13

    Z. Y. Pei, J. H. Fan, Y. Liu, Y. H. Yuan, W. Cai, H. B. Xiao, C. Lin, and J. H. Yang, Astrophys. Space Sci. 361, 237 (2016).

  14. 14

    D. Xiong, X. Zhang, J. Bai, and H. Zhang, Mon. Not. R. Astron. Soc. 451, 2750 (2015), arXiv: 1505.01408.

  15. 15

    J. H. Fan, and J. S. Zhang, Astron. Astrophys. 407, 899 (2003).

  16. 16

    J. H. Fan, J. H. Yang, J. Pan, and T. X. Hua, Res. Astron. Astrophys. 11, 1413 (2011).

  17. 17

    A. A. Abdo, et al. (The Fermi-LAT Collaboration), Astrophys. J. Suppl. Ser. 183, 46 (2009), arXiv: 0902.1340.

  18. 18

    A. A. Abdo, et al. (The Fermi-LAT Collaboration), Astrophys. J. Suppl. Ser. 188, 405 (2010), arXiv: 1002.2280.

  19. 19

    F. Acero, et al. (The Fermi-LAT Collaboration), Astrophys. J. Suppl. Ser. 218, 23 (2015), arXiv: 1501.02003.

  20. 20

    P. L. Nolan, et al. (The Fermi-LAT Collaboration), Astrophys. J. Suppl. Ser. 199, 31 (2012), arXiv: 1108.1435.

  21. 21

    S. Abdollahi, et al. (The Fermi-LAT Collaboration), arXiv: 1902.10045.

  22. 22

    S. Abdollahi, et al. (The Fermi-LAT Collaboration), arXiv: 1905.10771.

  23. 23

    Z. Y. Pei, J. H. Fan, D. Bastieri, U. Sawangwit, and J. H. Yang, Res. Astron. Astrophys. 19, 070 (2019), arXiv: 1811.08774.

  24. 24

    Z. Y. Pei, J. H. Fan, D. Bastieri, J. H. Yang, H. B. Xiao, and W. X. Yang, arXiv: 1909.06177.

  25. 25

    A. A. Abdo, M. Ackermann, M. Ajello, A. Allafort, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, A. Cannon, P. A. Caraveo, J. M. Casandjian, C. Cecchi, O. Celik, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C. D. Dermer, A. de Angelis, F. de Palma, S. W. Digel, E. do Couto e Silva, P. S. Drell, A. Drlica-Wagner, R. Dubois, Favuzzi, S. J. Fegan, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, S. Guiriec, M. Gustafsson, D. Hadasch, A. K. Harding, K. Hayashi, M. Hayashida, Hays, S. E. Healey, P. Jean, G. Johannesson, A. S. Johnson, R. P. Johnson, T. J. Johnson, T. Kamae, H. Katagiri, J. Kataoka, M. Kerr, J. Knodlseder, M. Kuss, J. Lande, L. Latronico, S. H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, P. Martin, M. N. Mazziotta, J. Mehault, P. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, Parent, M. Pepe, M. Persic, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Raino, R. Rando, M. Razzano, A. Reimer, O. Reimer, S. Ritz, R. W. Romani, H. F. W. Sadrozinski, P. M. Saz Parkinson, C. Sgro, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, M. S. Strickman, L. Strigari, A. W. Strong, D. J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, J. Vandenbroucke, G. Vianello, N. Vilchez, V. Vitale, A. P. Waite, P. Wang, B. L. Winer, K. S. Wood, Z. Yang, and M. Ziegler, Astron. Astrophys. 523, L2 (2010), arXiv: 1012.1952.

  26. 26

    J. Fan, J. H. Yang, J. Y. Zhang, T. X. Hua, Y. Liu, Y. P. Qin, and Y. Huang, Publ. Astron. Soc. Jpn. 65, 25 (2013), arXiv: 1210.4096.

  27. 27

    A. De Angelis, and M. Mallamaci, Eur. Phys. J. Plus 133, 324 (2018), arXiv: 1805.05642.

  28. 28

    S. Ostapchenko, Phys. Rev. D 83, 014018 (2011), arXiv: 1010.1869.

  29. 29

    T. Pierog, I. Karpenko, J. M. Katzy, E. Yatsenko, and K. Werner, Phys. Rev. C 92, 034906 (2015).

  30. 30

    G. Ghisellini, Adv. Space Res. 13, 587 (1993).

  31. 31

    G. Z. Xie, E. W. Liang, S. B. Zhou, K. H. Li, B. Z. Dai, and L. Ma, Mon. Not. R. Astron. Soc. 334, 459 (2002).

  32. 32

    G. Z. Xie, L. E. Chen, H. Z. Li, L. S. Mao, H. Dai, Z. H. Xie, L. Ma, and S. B. Zhou, Chin. J. Astron. Astrophys. 5, 463 (2005).

  33. 33

    J. H. Fan, G. Z. Xie, and R. Bacon, Astron. Astrophys. Suppl. Ser. 136, 13 (1999).

  34. 34

    I. Liodakis, T. Hovatta, D. Huppenkothen, S. Kiehlmann, W. Max-Moerbeck, and A. C. S. Readhead, Astrophys. J. 866, 137 (2018), arXiv: 1809.08249.

  35. 35

    B. J. Wills, D. Wills, M. Breger, R. R. J. Antonucci, and R. Barvainis, Astrophys. J. 398, 454 (1992).

  36. 36

    Z. Fan, X. Cao, and M. Gu, Astrophys. J. 646, 8 (2006).

  37. 37

    J. H. Fan, J. H. Yang, J. Tao, Y. Huang, and Y. Liu, Publ. Astron. Soc. Jpn. 62, 211 (2010).

  38. 38

    D. X. Wu, J. H. Fan, Y. Liu, J. H. Yang, J. M. Hao, Z. Y. Pei, and C. Lin, Publ. Astron. Soc. Jpn. 66, 117 (2014).

  39. 39

    J. H. Fan, Astrophys. J. 585, L23 (2003).

  40. 40

    F. W. Stecker, C. R. Shrader, and M. A. Malkan, arXiv: 1903.06544.

  41. 41

    M. Di Mauro, F. Calore, F. Donato, M. Ajello, and L. Latronico, Astrophys. J. 780, 161 (2014), arXiv: 1304.0908.

  42. 42

    D. Hooper, T. Linden, and A. Lopez, J. Cosmol. Astropart. Phys. 2016(08), 019 (2016), arXiv: 1604.08505.

  43. 43

    E. Nieppola, M. Tornikoski, E. Valtaoja, J. Leon-Tavares, T. Hovatta, A. Lahteenmaki, and J. Tammi, Astron. Astrophys. 535, A69 (2011), arXiv: 1109.5844.

  44. 44

    I. Liodakis, N. Marchili, E. Angelakis, L. Fuhrmann, I. Nestoras, I. Myserlis, V. Karamanavis, T. P. Krichbaum, A. Sievers, H. Ungerechts, and J. A. Zensus, Mon. Not. R. Astron. Soc. 466, 4625 (2017), arXiv: 1701.01452.

  45. 45

    T. Hovatta, E. Valtaoja, M. Tornikoski, and A. Lahteenmaki, Astron. Astrophys. 494, 527 (2009), arXiv: 0811.4278.

  46. 46

    J. H. Fan, Y. Huang, T. M. He, J. H. Yang, T. X. Hua, Y. Liu, and Y. X. Wang, Publ. Astron. Soc. Jpn. 61, 639 (2009).

  47. 47

    J. H. Fan, K. S. Cheng, and L. Zhang, Publ. Astron. Soc. Jpn. 54, 533 (2002).

  48. 48

    B. L. Fanaroff, and J. M. Riley, Mon. Not. R. Astron. Soc. 167, 31P (1974).

  49. 49

    R. I. Kollgaard, J. F. C. Wardle, D. H. Roberts, and D. C. Gabuzda, Astron. J. 104, 1687 (1992).

  50. 50

    D. W. Murphy, I. W. A. Browne, and R. A. Perley, Mon. Not. R. Astron. Soc. 264, 298 (1993).

  51. 51

    G. Z. Xie, Y. H. Zhang, J. H. Fan, and F. K. Liu, Astron. Astrophys. 278, 6 (1993).

  52. 52

    A. Capetti, E. Trussoni, A. Celotti, L. Feretti, and M. Chiaberge, Mon. Not. R. Astron. Soc. 318, 493 (2000).

  53. 53

    A. Capetti, and A. Celotti, Mon. Not. R. Astron. Soc. 304, 434 (1999).

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Correspondence to ZhiYuan Pei or JunHui Fan.

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Pei, Z., Fan, J., Bastieri, D. et al. Radio core dominance of Fermi/LAT-detected AGNs. Sci. China Phys. Mech. Astron. 63, 259511 (2020). https://doi.org/10.1007/s11433-019-1454-6

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Key words

  • active galactic nuclei (AGNs)
  • quasars
  • γ-rays