RATAN-600 multi-frequency measurements of GRS1915+105
ATel #12855; S. A. Trushkin, N. A. Nizhelskij, P. G. Tsybulev, N. N. Bursov, A. V. Shevchenko (SAO RAS, Russia)
on 9 Jun 2019; 13:45 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Sergei Trushkin (satr@sao.ru)
Subjects: Radio, Infra-Red, X-ray, Request for Observations, Binary, Black Hole, Transient
We continue the monitoring of microquasar GRS 1915+105 at 2.3, 4.8, 8.2, 11.2 and 22.3 GHz with the RATAN-600 radio telescope (see also ATEL #1509, #2899). During 1 April - 11 May 2019 we have detected the source at level less 10 mJy at 4.8 GHz. After 8 May the microquasar entered in very low flux state (Swift/BAT data in ATEL #12743), like the similar state in 2007 (within MJD54300-54550, see the plot in ATel #1509). We restarted the daily observations on 16 May 2019 (MJD 58619) and we have detected GRS1915+105 with fluxes about 100 mJy at 11.2 GHz just after X-ray events detected with Swift/BAT (15-50 keV) and MAXI (2-20 keV). Our data agree with AMI-LA data (ATel #12773). The spectra of the detected optically thin or thick synchrotron emission are well fitted by power laws with different spectral indices
http://www.sao.ru/hq/lran/XB/1915_sp_2019.png
The most bright flaring event (obviously related with a jet ejection) was detected on 4 June (MJD 58637.99) after near one day from the brightest event detected by MAXI on MJD 58636.78. The spectrum is well fitted by: S_nu[mJy] = 720nu[GHz]^-0.3. Such flux densities are the most high during two last years and obviously related with flaring X-ray activity. The light curves (RATAN, MAXI and Swift/BAT) of GRS 1915+105 during May-June 2019 are shown below. We will daily conduct the multi-frequency observations. Observations in other spectral bands are strongly encouraged.
The RATAN multi-frequency light curves of GRS1915+105 in May-June 2019
