Un modelo leptónico para la emisión electromagnética de microcuásares

Gustavo E. Romero (IAR -- FCAGLP), Valenti Bosch-Ramon (UB), & Josep María Paredes (UB)

AAA 05, Septiembre 2005

Microquasars: accreting X-ray binaries with jet-like radio features

The Power-Evolution of Black Hole XRBs

Accretion DiskRadio & X-ray Spectrum Radio Jet

M

Fender (2001)Fender (2001)

High-mass microquasars: leptonic models

The jet must traverse different external photon fields generated by the hot corona, the accretion disk and the companion star. IC interactions between relativistic leptons in the jet and the external photons may produce a significant gamma-ray flux. If a magnetic field is present, SSC interactions will also contribute to the high-energy emission.

Basics of the Leptonic ModelBasics of the Leptonic Model

The jet is dynamically dominated by cold protons and radiatively dominated by relativistic leptons.

The matter content and power of the jet are both related to the accretion process.

The magnetic field is considered to be close to equipartition, although it is attached to and dominated by the jet matter.

Concerning the relativistic particles in the jet, their maximum energy depends on both the acceleration efficiency and the energy losses.

Basics of the Leptonic ModelBasics of the Leptonic Model

Basics of the Leptonic ModelBasics of the Leptonic Model

Particle distribution:

Basics of the Leptonic ModelBasics of the Leptonic Model

Radiative processes considered:

•Synchrotron emission•Relativistic Bremsstrahlung•Invese Compton emission with a) external (corona, disk, and star) photon fields b) internal (synchrotron-SSC-, Bremsstahlung-BSC-, and Compton-CSC-) photon fileds.

Full Klein-Nishina cross-section was used in the calculations.

In addition, we considered pair creation and annihilation in the jet and opacities to high-energy photons in the different fields were computed and taken into account.

Evolution of the maximum Lorentz factor for leptons in the jet

Evolution of the bulk Lorentz factor of the jet

Energy losses for electrons along the jet

Opacity to gamma-ray propagation along the jet

Results: model A

Results: model B

Results: model C

Results: model D

In July, 2005, the microquasar LS 5039 was detected by HESS

Detection of LS 5039 in very high energygamma rays by H.E.S.S. Science 309, July 2005

LS5039 had already been associatedwith the EGRET source3EG 1824-1514 by Paredes et al. 2000 (Science 288).

The leptonic model applied to the MQ LS 5039

Future ObservationsFuture Observations

I. , “the EGRET successor” 30 MeV - 300 GeV. The sensitivity is expected to be about 10 to 100 times better than EGRET’s.

GLASTGLAST

II. TeV-Sources vs Cherenkov telescopesCherenkov telescopes

HESSHESS

VERITASVERITASMAGICMAGIC