Long-term multi-frequency studies of flaring activity from microquasars

Autor: N. Nizhelsky, P. Tsybulev, N. Bursov, A. Shevchenko, S. Trushkin
Rok vydání: 2022
Zdroj: ASTRONOMY AT THE EPOCH OF MULTIMESSENGER STUDIES. Proceedings of the VAK-2021 conference, Aug 23–28, 2021.
Popis: The long-term monitoring at RATAN-600 of studies of bright X-ray binary stars in various ranges of the electromagneticspectrum, a search and detailed study of correlations between variable X-ray, radio and gamma radiation was carried out.It is a key point for understanding the formation of jet emissions from accreting matter onto a black hole (or neutron star).From April 2019 For a year, we began to use the multi-azimuth measurement mode on the Southern Sector antenna systemwith a flat reflector, when 31 measurements of flux densities at frequencies 4.7, 8.6, 15 and 30 GHz of several giant CygnusX-3 flares, SS433 [1] and GRS1915+105 bright flashes were carried out for 5–6 hours around the culmination of the source.In January 2020, Cyg X-3 switched to a hyper-soft X-ray state, the exit from which in early February led to the brightest theradio flash for the all history of its observations. The Cygnus X-3 flow density increased from 5 mJy to 20 Jy at a frequencyof 4.7 GHz and up to 22 Jy at 2.3 GHz in 2–3 days. In multi-azimuthal observations in the beginning phase, we registered alinear law of increase in the flux at times from 1 to 5 hours. Comparing the data of the space Gamma-ray telescopes (Swift,AGILE and Fermi) and the MAXI and NICER X-ray monitors on board the ISS, we found that flaring events from the radioto the Gamma-rays are interrelated, which is a reflection of the causal relationship of physical processes in the accretiondisk and in jet emissions. The spectral and time dependence of the evolution of flares allow us to model the synchrotronradiation of microquasars based on changes in the volume of jet emissions, the strength of their magnetic field and the modeof generation and absorption of radio radiation from relativistic electrons. Radio flares of the microquasar GRS1915+105,as a clear manifestation of a new jet activity, always have the character of a reaction to changes in the conditions forgenerating X-rays in the accretion disk (MAXI) and in the corona (Swift). We have studied in details periodic radio flaresfrom the X-ray binary with bright Gamma-ray radiation LSI+61d303 for more than 60 orbital periods. Undoubtedly, thenature of these flares changes dramatically depending on the known super-orbital 4.6-year period.
Databáze: OpenAIRE