Multi-frequency Radio Observations of Cygnus X-3 at the Time of Giant Flare of May 2006
We are reporting a multi-frequency radio observation of the galactic high mass X-ray binary Cygnus X-3 when the source underwent a major flare which is one of the largest in recorded history. We used Giant Metrewave Radio Telescope (GMRT) at 244 and 614 MHz and Very Large Array (VLA) at 8.43 and 43.3 GHz. We have studied evolution of radio spectrum during both rising and fading part of the flare using GMRT and VLA measurements along with published data using RATAN telescope. The radio spectrum showed turn-over which shifted towards lower frequencies as the flare progresses and correspondingly the two point spectral index between 244 and 614 MHz shows clear transition from positive (optically thick) and negative (optically thin) values. We showed that this behavior is consistent with the synchrotron self absorption model. Using this model, we also obtain the physical parameters such as the size of the emitting region and the velocity of the expansion of the radio emitting synchrotron blob. If we assume the magnetic field strength in the range 0.1 to 1 Gauss, then the the velocity of the expansion of the blob becomes in the range 0.02c to 0.17c.
Sabyasachi Pal C. H. Ishwara-Chandra A. Pramesh Rao
National Centre of Radio Astrophysics, Tata Institute of Fundamental Research, Pune, India
国际会议
The 10th Asian-Pacific Regional International Astronomical Union Meeting(第十届亚洲及太平洋地区天文学大会 APRIM)
昆明
英文
254-255
2008-08-03（万方平台首次上网日期，不代表论文的发表时间）