Abstract
A subset of the unidentified EGRET γ-ray sources with no active galactic nucleus or other conspicuous counterpart appears to be concentrated at medium latitudes. Their long-term variability and their spatial distribution indicate that they are distinct from the more persistent sources associated with the nearby Gould Belt. They exhibit a large scale height of 1.3 ± 0.6 kpc above the Galactic plane. Potential counterparts for these sources include microquasars accreting from a low-mass star and spewing a continuous jet. Detailed calculations have been performed of the jet inverse Compton emission in the radiation fields from the star, the accretion disc, and a hot corona. Different jet Lorentz factors, powers, and aspect angles have been explored. The up-scattered emission from the corona predominates below 100 MeV whereas the disc and stellar contributions are preponderant at higher energies for moderate (∼15°) and small (∼1°) aspect angles, respectively. Yet, unlike in the high- mass, brighter versions of these systems, the external Compton emission largely fails to produce the luminosities required for 5 to 10 kpc distant EGRET sources. Synchrotron-self-Compton emission appears as a promising alternative.
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References
Atoyan, A.M. and Aharonian, F.A.: 1999, MNRAS 302, 253.
Bosch-Ramon, V., Romero, G.E. and Paredes, J.M.: 2004, A&A, submitted, astro-ph/0405017.
Chaty, S., Haswell, C.A., Malzac, J., Hynes, R.I., Shrader, C.R. and Cui, W.: 2003, MNRAS 346, 689.
Corbel, S., Fender, R.P., Tzioumis, A.K., Tomsick, J.A., Orosz, J.A., Miller, J.M., Wijnands, R. and Kaaret, P.: 2002, Science 298, 196.
Dermer, C.D., Schlickeiser, R. and Mastichiadis, A.: 1992, A&A 256, L27.
Dermer, C.D. and Schlickeiser, R.: 2002, ApJ 575, 667.
Esin, A.A., McClintock, J.E., Drake, J.J., Garcia, M.R., Haswell, C.A., Hynes, R.I. and Muno, M.P.: 2001, ApJ 555, 483.
Eadie, W.T., et al.: 1977, Statistical Methods in Experimental Physics, North-Holland Publ., p. 279.
Fender, R., et al.: 2004, Nature 427, 222.
Gehrels, N., Macomb, D.J., Bertsch, D.L., Thompson, D.J. and Hartman R.C.: 2000, Nature 404, 363.
Georganopoulos, M., Aharonian, F.A. and Kirk, J.G.: 2002, A&A 388, L25.
Grenier, I.A.: 2000, A&A 364, L93.
Grenier, I.A.: 2004, in: K. S. Cheng and G.E. Romero (eds.), Cosmic Gamma-Ray Sources, Kluwer Academic Publishers, in press.
Hartman, R.C., Bertsch, D.L., Bloom, S.D., et al.: 1999, ApJ 123, 79.
Hynes, R.I., et al.: 2003, MNRAS 345, 292.
Kaufman Bernardó, M.M., et al.: 2002, A&A 385, L10.
Kirk, J.G., Ball, L. and Skjaeraasen, O.: 1999, Astroparticle Phys. 10, 31.
Kniffen, D.A., et al.: 1997, ApJ 486, 126.
Kuiper, L., et al.: 2002, ApJ 577, 917.
Malzac, J., Merloni, A. and Fabian, A.C.: 2004, MNRAS 351, 253.
Massi, M.: 2004, A&A 422, 267.
Mattox, J.R., Hartman, R.C. and Reimer, O.: 2001, ApJS 135, 155.
McClintock, J.E., et al.: 2001, ApJ 551, L147.
McClintock, J.E., et al.: 2001, ApJ 555, 477.
Mirabel, I.F., et al.: 2001, Nature 413, 139.
Nolan, P., et al.: 2003, ApJ 597, 615.
Paredes, J.M., Marti, J., Ribo, M. and Massi, M., 2000, Science 288, 2340.
Romero, G.E., Benaglia, P. and Torres, D.F.: 1999, A&A 348, 868.
Romero, G.E., Kaufman Bernardó, M.M. and Mirabel, I.F.: 2002, A&A 393, L61.
Romero, G.E., Grenier, I.A., Kaufman Bernardó, M.M., Mirabel, I.F. and Torres, D.F.: 2004, Proceedings of the Vth INTEGRAL Workshop, Munich 2004, ESA SP-552, in press. astro-ph/0402285.
Sowards-Emmerd, D., Romani, R.W. and Michelson, P.: 2003, ApJ 590, 109.
Sowards-Emmerd, D., Romani, R.W., Michelson, P.F. and Ulvestad, J.S.: 2004, ApJ 609, 564.
Torres, M.A.P., et al.: 2002, ApJ 569, 423.
Wagner, R.M., et al.: 2001, ApJ 556, 42.
Zhang, L. and Cheng, K.S.: 2003, A&A 398, 639.
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Grenier, I., Kaufman Bernadó, M., Romero, G. (2005). Unidentified γ-Ray Sources off the Galactic Plane as Low-Mass Microquasars?. In: Cheng, K., Romero, G. (eds) Multiwavelength Approach to Unidentified Gamma-Ray Sources. Springer, Dordrecht. https://doi.org/10.1007/1-4020-3881-X_12
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DOI: https://doi.org/10.1007/1-4020-3881-X_12
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