Fermi-LAT detection of enhanced gamma-ray activity from BL Lac
Abstract
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed enhanced gamma-ray activity from a source positionally consistent with BL Lacertae, also known as 4FGL J2207.1+4316 (The Fermi-LAT collaboration 2020, ApJS, 247, 33), with coordinates R.A.=22:02:43.29137 Dec.=+42:16:39.9799 (J2000; Beasley et al. 2002, ApJS, 141, 13), and redshift z=0.0686 (Vermeulen et al., 1995, ApJ, 452, L5). Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on 2021-04-27, with a daily averaged gamma-ray flux (E > 100MeV) of (7.7+/-0.3) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only).
- Publication:
-
The Astronomer's Telegram
- Pub Date:
- April 2021
- Bibcode:
- 2021ATel14583....1L
- Keywords:
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- AGN;
- Blazar