engleski

First detection of very-high-energy gamma-ray emission from the extreme blazar PGC 2402248 with the MAGIC telescopes

The MAGIC collaboration reports the first detection of very-high-energy (VHE ; E>100 GeV) gamma-ray emission from PGC 2402248, also known as 2WHSP J073326.7+515354 (Chang et al. 2016, A&A, 598, A17) with coordinates R.A.: 07:33:26.7 h, Dec: +51:53:54.99 deg. The source is classified as an extreme high-energy peaked BL Lacertae object of unknown redshift, included in the 2WHSP catalog with a synchrotron peak located at 10^17.9 Hz. PGC 2402248 was observed with the MAGIC telescopes from 2018/01/23 to 2018/04/18 (MJD 58141-58226) for about 23 h. The preliminary analysis of these data resulted in the detection of PGC 2402248 with a statistical significance of more than 6 standard deviations. The VHE integral flux was estimated to be (2.2 +/- 0.6)e-12 ph cm^-2 s-1 above 200 GeV, corresponding to around 1% of the Crab Nebula flux above the same energy threshold. The source was also observed with the XRT instrument on-board the Neil Gehrels Swift Observatory from 2018/01/26 to 2018/04/08 (MJD 58144-58216) with 7 visits almost contemporaneous to the MAGIC observations. The preliminary analysis performed with the publicly available tools (http://www.swift.ac.uk/results/index.php) shows a hint of flux variability from a minimum count rate of 0.43 (MJD 58164) to a maximum of 0.62 cnt/s during the last observation (MJD 58216), in the 0.3-10 keV range. MAGIC and Swift/XRT observations of PGC 2402248 will continue during the next days and multiwavelength observations are encouraged. The MAGIC contact persons for these observations are R. Mirzoyan (Razmik.Mirzoyan@mpp.mpg.de), L. Foffano (luca.foffano@phd.unipd.it) and J. Becerra Gonzalez (jbecerra@iac.es). MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located on the Canary island of La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV. We would like to thank the Swift Team for making these observations possible.

TeV ; VHE ; AGN ; Blazar

nije evidentirano