Thursday, May 21, 2015

Newest blazar discoveries in VHE gamma-rays band

  1. Discovery of Very High Energy Gamma-Ray Emission from the distant FSRQ PKS 1441+25 with the MAGIC telescopes: This source is the second distant VHE gamma-ray source with the redshift of 0.939 (Shaw et al. 2012, ApJ, 748, 49). It is discovered by MAGIC on April 20, 2015. MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV. The flux above 80 GeV is estimated to be about 8e-11 cm^-2 s^-1 (16% of Crab Nebula flux). Preliminary analysis show detection significant of 6 standard deviations during ~2 hours observation in the night between 17 and 18 of April; and 11 standard deviations during ~4 hours observations in the night between 18 and 19 of April (http://www.astronomerstelegram.org/?read=7416 ). The highest optical R-band magnitude is 15.6 and was measured in the night between 21 and 22 April using KVA telescope (http://users.utu.fi/kani/1m/PKS_1441+25.html ).
  2. MAGIC detects an increased activity from FSRQ PKS 1510-089 at very high energy gamma-rays: The redshift of this source is 0.36. The preliminary analysis shows a highly significant signal and a flux of ~20% from that of the Crab nebula above 100 GeV for the data taken from 2015/05/18 to 2015/05/19. This implies an increase by a factor of ~5 with respect to the flux reported previously in 2012. The source is active now in Optical and IR-band as well (http://www.astronomerstelegram.org/?read=7542 ). We are performing optical monitoring in R-band using KVA telescope. The current flare in Optical is the second one after 6 years since the monitoring of this source started in the Tuorla blazar monitoring program (http://users.utu.fi/kani/1m/PKS_1510-089.html )