Enhanced X-Ray Activity in the TeV-detected Blazar RGB J0710+591
ATel #15830; Bidzina Kapanadze (E. Kharadze National Astrophysical Observatory; Ilia State University, Tbilisi, Georgia; INAF-OAB, Merate, Italy)
on 27 Dec 2022; 19:59 UT
Credential Certification: Bidzina Kapanadze (bidzina_kapanadze@iliauni.edu.ge)
The TeV-detected HBL object RGB J0710+591 (z=0.125) was targeted 66 times with X-Ray Telescope onboard Neil Gehrels Swift Observatory (Swift-XRT) during 2009 February 20 - 2017 December 23 with a net exposure of 78 ks. During that period, the 0.3-10 keV count rate showed an overall variability by a factor of ~5.3 with the maximum value of 3.10+/-0.07 cts/s and long-term (several years) decline in the baseline X-ray level (see https://www.swift.psu.edu/monitoring/source.php?source=RGBJ0710+591). The latter can be related to the long-term variability in the jet matter collimation rate, triggered to some instable processes in the accretion disc (see, e.g., Kapanadze et al. 2018, ApJS, 238, 13). We have renewed the Swift monitoring of the source (Swift-TOO Request Number 18265; 8 observations between 2022 December 26 and 2023 February 13, each of 2 ks exposure). The first observations of this campaign detected RGB J0710+591 in the significantly elevated X-ray state: the 0.3-10 keV count rate was 1.24+/-0.07 cts/s, which is a factor 2 higher than that recorded during the previous XRT visit to the source. The extracted spectrum is very hard with the photon index at 1 keV $a$=1.77+/-0.07, the curvature parameter $b$=0.39+/-0.14 and the unabsorbed 0.3-10 keV flux of (4.02+/-020)\times10^{-11}erg/cm^2/s. Since the enhanced activity is expected in the framework of one-zone SSC scenario, we strongly encourage intense MWL observations with the space and ground-based instruments.
XRT is one of the Swift instruments along with Burst Alert Telescope (BAT) and UV/Optical Telescope (UVOT). It is a JET-X Wolter I type telescope, developed jointly by Pennsylvania State University, Brera Astronomical Observatory (OAB) and University of Leicester. Thanks to the unique characteristics, good photon statistics and low background counts of this instrument (in combination with EEV CCD2 detector), we can investigate a flux variability on different time-scales from minutes to years, obtain high-quality spectra for the majority of the observations, derive different spectral parameters, and study their timing behaviour in the 0.3-10 keV range of the electromagnetic spectrum. The Swift Satellite is operated by Pennsylvania State University.
