High X-Ray State in HBL Source Mrk 421

ATel #4792; Bidzina Kapanadze (Ilia State Iniversity)
on 6 Feb 2013; 17:59 UT
Credential Certification: Bidzina Kapanadze (bidzina_kapanadze@iliauni.edu.ge)

Tweet

We report a high X-ray State through 0.3-10 keV band in the high-energy peaked BL Lacertae source Mrk 421 (z=0.031) which was observed five times between 2013 January 25 and February 6 with the X-ray Telescope (XRT) onboard the Swift satellite. Using the data allocated at the webpage http://www.swift.psu.edu/monitoring/, it was found that the object increased its 0.3-10 keV flux from 11.80+/-0.14 cts/s (January 25, ObsID=00035025038) to 34.60+/-0.39 cts/s corresponding to the first orbit of the observation performed on February 4 (ObsID=00035025041). Then it showed a decay during the rest part of the pointing and dropped to 23.67+/-0.31 cts/s in the case of third orbit, separated by about 11 hr from the first one. During the last observation (ObsID=00035025042), the source showed the average 0.3-10 keV flux of 21.48+/-0.07 cts/s but it is still almost twice high compared to its initial level. Furthermore, the object showed again a fast variability – the reduced chi square is equal to 3.325 with 95 d.o.f. for this pointing, lasting less than 3.7 hr. In that case, the flux decreased from 21.65+/-0.13 cts/s (Orbit 1) to 20.30+/-0.11 cts/s (Orbit 2) and then rose to 22.82+/-0.13 cts/s (Orbit 3). Since a high-energy brightening in BL Lacertae sources is often followed by those at longer wavelength, we encourage intensive observations of Mrk 421 with the optical-infrared-radio telescopes.