The Highest Historical 0.3-10 keV Flux in TeV Blazar 1ES 1011+496
ATel #5866; Bidzina Kapanadze (Ilia State University, Tbilisi, Georgia)
on 9 Feb 2014; 16:11 UT
Credential Certification: Bidzina Kapanadze (bidzina_kapanadze@iliauni.edu.ge)
We report the highest historical 0.3-10 keV brightness of a distant (z=0.212) TeV BL Lacertae source MS1221.8+2452 (z=0.218, also known as H 1011+496, 1FGL J1015.1+4927, BZBJ1015+496) in the 0.3-10 keV energy band detected by the X-ray Telescope (XRT) onboard the Swift satellite which observed the source 3 times during February 7-9 (total exposure - about 4 hr). Using the data provided at http://www.swift.psu.edu/monitoring/ , we have found that the object showed the 0.3-10 keV flux of 3.50+/-0.07 cts/s on February 7 which is with 38% higher compared to the highest flux recorded during the past observations. The flux was practically at the same level in the case of next observation and increased with 11% until the pointing performed on February 9 (F(0.3-10 keV)=3.88+/-0.09 cts/s. In the framework of one-zone SSC model, an increased activity is also expected in the UV-radio and gamma-ray bands and intensive multiwavelength observations of 1ES 1011+496 will be very important to study nonstationary processes and emission mechanisms in this source. Since the current flux level is much higher of the Swift-XRT pileup threshold (about 0.5 cts/s), we recommend a windowed timing (WT) mode for upcoming observations with this telescope instead the photon counting (PC) ones adopted during the past days.
