EDP Sciences
Free Access
Volume 429, Number 1, January I 2005
Page(s) 267 - 276
Section Stellar structure and evolution
DOI https://doi.org/10.1051/0004-6361:20041194
Published online 13 December 2004

A&A 429, 267-276 (2005)
DOI: 10.1051/0004-6361:20041194

High-mass microquasars and low-latitude gamma-ray sources

V. Bosch-Ramon1, G. E. Romero2, 3 and J. M. Paredes1

1  Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona, Spain
    e-mail: vbosch@am.ub.es;jmparedes@ub.edu
2  Instituto Argentino de Radioastronomía, C.C.5, (1894) Villa Elisa, Buenos Aires, Argentina
    e-mail: romero@iar.unlp.edu.ar
3  Facultad de Ciencias Astronómicas y Geofísicas, UNLP, Paseo del Bosque, 1900 La Plata, Argentina

(Received 29 April 2004 / Accepted 11 August 2004 )

Population studies of unidentified EGRET sources suggest that there exist at least three different populations of galactic gamma-ray sources. One of these populations is formed by young objects distributed along the galactic plane with a strong concentration toward the inner spiral arms of the Galaxy. Variability, spectral and correlation analysis indicate that this population is not homogeneous. In particular, there is a subgroup of sources that display clear variability in their gamma-ray fluxes on timescales from days to months. Following the proposal by Kaufman Bernadó et al. (2002), we suggest that this group of sources might be high-mass microquasars, i.e. accreting black holes or neutron stars with relativistic jets and early-type stellar companions. We present detailed inhomogeneous models for the gamma-ray emission of these systems that include both external and synchrotron self-Compton interactions. We have included effects of interactions between the jet and all external photon fields to which it is exposed: companion star, accretion disk, and hot corona. We make broadband calculations to predict the spectral energy distribution of the emission produced in the inner jet of these objects up to GeV energies. The results and predictions can be tested by present and future gamma-ray instruments like INTEGRAL, AGILE, and GLAST.

Key words: X-rays: binaries -- stars: winds, outflows -- gamma-rays: observations -- gamma-rays: theory

SIMBAD Objects

© ESO 2004

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