Another Strong X-Ray flare in the TeV-Detected Blazar 1ES 0647+250

ATel #14264; Bidzina Kapanadze (Ilia State University, Tbilisi, Gerogia; E. Kharadze National Astrophysical Observatory, Abastumani, Georgia)
on 14 Dec 2020; 08:07 UT
Credential Certification: Bidzina Kapanadze (bidzina_kapanadze@iliauni.edu.ge)

Tweet

The TeV-detected blazar of unknown redhsift 1ES 0647+250 has been targeted 63 times with X-Ray Telescope onboard Neil Gehrels Swift Observatory during 2010 March 6 - 2020 December 13 with a net exposure of 101 ks. During this period, the 0.3-10 keV count rate varied by a factor of ~6, and reached the value of 5.14+/-0.08 cts/s on 2019 December 3 when the source was showing a strong X-ray flaring activity since the previous month (observed mostly in the framework of our ToO requests of different urgency; see http://www.swift.psu.edu/monitoring /source.php?source=QSOB1727+502; Kapanadze B., ATel#13324). Meanwhile, the TeV-band observations with MAGIC resulted in the detection of the source with a significance higher than 5 sigma during 2019 December 2-4, corresponding to about 10% of the flux of the Crab Nebula above 100 GeV (Mirzoyan et al. ATel#13324). Another strong X-ray flare by a factor of ~3.5 was recorded in 2020 February. The first observation of our current TOO request (Number 14942), performed on December 13, detected the source in another strong X-ray flaring state: the 0.3-10 keV count rate amounted to 2.56+/-0.16 cts/s, which is a factor of ~2.5 higher than that shown by the source during the previous XRT observation (on March 6). In the framework of one-zone SSC models, a flaring activity of 1ES 0647+250 is also expected in the UV-radio and gamma-ray parts of the spectrum, and intense multiwavelength observations of the source are strongly encouraged for discerning the underlying emission mechanisms and instable processes. 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.