Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-08-16
Astrophys.J.634:L81-L84,2005
Astronomy and Astrophysics
Astrophysics
Submitted to ApJ Letters. AASTeX, 12 ms pages, including 4 eps figures
Scientific paper
10.1086/498615
Very high energy (VHE) gamma-rays have recently been detected from the Galactic black-hole candidate and microquasar LS 5039. A plausible site for the production of these VHE gamma-rays is the region close to the mildly relativistic outflow. However, at distances comparable to the binary separation, the intense photon field of the stellar companion will lead to substantial gamma-gamma absorption of VHE gamma-rays. If the system is viewed at a substantial inclination (i > 0), this absorption feature will be modulated on the orbital period of the binary as a result of a phase-dependent stellar-radiation intensity and pair-production threshold. We apply our results to LS 5039 and find that (1) gamma-gamma absorption effects will be substantial if the photon production site is located at a distance from the central compact object of the order of the binary separation (~ 2.5e12 cm) or less; (2) the gamma-gamma absorption depth will be largest at a few hundred GeV, leading to a characteristic absorption trough; (3) the gamma-gamma absorption feature will be strongly modulated on the orbital period of the binary, characterized by a spectral hardening accompanying periodic dips of the VHE gamma-ray flux; and (4) gamma rays can escape virtually unabsorbed, even from within ~ 10^{12} cm, when the star is located behind the production site as seen by the observer.
Boettcher Markus
Dermer Carles D.
No associations
LandOfFree
Photon-Photon Absorption of Very High Energy Gamma-Rays from Microquasars: Application to LS 5039 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Photon-Photon Absorption of Very High Energy Gamma-Rays from Microquasars: Application to LS 5039, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photon-Photon Absorption of Very High Energy Gamma-Rays from Microquasars: Application to LS 5039 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-130796