Abstract
Population synthesis is used to study the contribution from unresolved sources to the Galactic ridge emission measured by EGRET. Synthesized source counts are compared with the 3rd EGRET catalogue at low and high latitudes. For pulsar-like populations, 5–10% of the emission >100 MeV comes from sources below the EGRET threshold. A steeper luminosity function can increase this to 20% without violating EGRET source statistics. Less luminous populations can produce much higher values without being detected. Since the unresolved source spectrum is different from the interstellar spectrum, it could provide an explanation of the observed MeV and GeV excesses above the predictions, and we give an explicit example of how this could work.
Similar content being viewed by others
References
Bergström, L., Edsjö, J., Gustafsson, M., Salati, P.: J. Cosmol. Astropart. Phys. 5, 6 (2006)
Bhattacharya, D., Akyüz, A., Miyagi, T., Samimi, J., Zych, A.: Astron. Astrophys. 404, 163 (2003)
Bouchet, L., Roques, J.P., Mandrou, P., et al.: Astrophys. J. 635, 1103 (2005)
Chen, A.W., Mereghetti, S., Pellizzoni, A., Tavani, M., Vercellone, S.: In: AIP Conf. Proc., vol. 587, p. 663. Gamma 2001: Gamma-Ray Astrophysics (2001)
Cheng, K.S., Zhang, L., Leung, P., Jiang, Z.J.: Astrophys. J. 608, 418 (2004)
de Boer, W., Sander, C., Zhukov, V., Gladyshev, A.V., Kazakov, D.I.: Astron. Astrophys. 444, 51 (2005)
Fierro, J.M., Michelson, P.F., Nolan, P.L., Thompson, D.J.: Astrophys. J. 494, 734 (1998)
Gehrels, N., Macomb, D.J., Bertsch, D.L., Thompson, D.J., Hartman, R.C.: Nature 404, 363 (2000)
Gonthier, P.L., Ouellette, M.S., Berrier, J., O’Brien, S., Harding, A.K.: Astrophys. J. 565, 482 (2002)
Gonthier, P.L., Coltisor, S., Harding, A.K.: In: Pulsars, AXPs and SGRs Observed with BeppoSAX and Other Observatories, pp. 115–120 (2003)
Gonthier, P.L., Van Guilder, R., Harding, A.K.: Astrophys. J. 604, 775 (2004)
Gonthier, P.L., Guilder, R., Harding, A.K., Grenier, I.A., Perrot, C.A.: Astrophys. Space Sci. 297, 71 (2005)
Harding, A.K., Zhang, B.: Astrophys. J. Lett. 548, L37 (2001)
Harding, A.K., Gonthier, P.L., Grenier, I.A., Perrot, C.A.: Adv. Space Res. 33, 571 (2004)
Kanbach, G., Bertsch, D.L., Dingus, B.L., et al.: Astron. Astrophys. Suppl. Ser. 120, C461 (1996)
Kuiper, L., Hermsen, W., Cusumano, G., et al.: Astron. Astrophys. 378, 918 (2001)
Lorimer, D.R.: In: IAU Symposium 218, p. 105. ASP, San Francisco (2004) astro-ph/0308501
Muslimov, A.G., Harding, A.K.: Astrophys. J. 588, 430 (2003)
Reimer, O., Thompson, D.J.: In: International Cosmic Ray Conference, p. 2566 (2001)
Revnivtsev, M., Sazonov, S., Gilfanov, M., Churazov, E., Sunyaev, R.: Astron. Astrophys. 452, 169 (2006)
Strong, A.W., Moskalenko, I.V., Reimer, O.: Astrophys. J. 613, 962 (2004a)
Strong, A.W., Moskalenko, I.V., Reimer, O., Digel, S., Diehl, R.: Astron. Astrophys. 422, L47 (2004b)
Strong, A.W., Diehl, R., Halloin, H., et al.: Astron. Astrophys. 444, 495 (2005)
Thompson, D.J., Bailes, M., Bertsch, D.L., et al.: Astrophys. J. 516, 297 (1999)
Zhang, L., Cheng, K.S.: Mon. Not. Roy. Astron. Soc. 301, 841 (1998)
Zhang, L., Zhang, Y.J., Cheng, K.S.: Astron. Astrophys. 357, 957 (2000)
Zhang, L., Cheng, K.S., Jiang, Z.J., Leung, P.: Astrophys. J. 604, 317 (2004)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Strong, A.W. Source population synthesis and the Galactic diffuse gamma-ray emission. Astrophys Space Sci 309, 35–41 (2007). https://doi.org/10.1007/s10509-007-9480-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10509-007-9480-1