A&A 417, 1075-1081 (2004)

DOI: 10.1051/0004-6361:20035615

## A numerical model for the -ray emission of the microquasar LS 5039

**V. Bosch-Ramon and J. M. Paredes**

Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona, Spain

e-mail: vbosch@am.ub.es,jmparedes@ub.edu

(Received 3 November 2003 / Accepted 6 January 2004 )

** Abstract **

The possible association between the microquasar LS 5039 and the EGRET source
3EG J1824-1514 suggests that microquasars could also be sources of high-energy
-rays. In
this paper, we explore, with a detailed numerical model, if this
system can produce the emission detected by EGRET (
>100 MeV) through inverse Compton (IC)
scattering. Our numerical approach considers a population of relativistic electrons entrained
in a cylindrical inhomogeneous jet, interacting with both the radiation and the magnetic
fields, taking into account the Thomson and Klein-Nishina regimes of interaction. The
computed spectrum reproduces the observed spectral characteristics at very high energy.

**Key words:**X-rays: binaries

**--**stars: individual: LS 5039

**--**gamma-rays: observations

**--**gamma-rays: theory

Offprint request: V. Bosch-Ramon, vbosch@am.ub.es

SIMBAD Objects

**©**

*ESO 2004*