Fermi-LAT detection of renewed gamma-ray activity from Fermi J0008+6829
ATel #15740; G. La Mura (LIP, Portugal), J. Valverde (UMBC/NASA GSFC), P. Bruel (CNRS/IN2P3, France), on behalf of the Fermi Large Area Telescope Collaboration
on 2 Nov 2022; 23:49 UT
Credential Certification: Giovanni La Mura (glamura@lip.pt)
Subjects: Gamma Ray, >GeV, Request for Observations, Transient
The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed renewed activity from a direction positionally consistent with the unassociated gamma-ray source Fermi J0008+6829, which is potentially associated with the unidentified flat-spectrum radio-source NVSS J000833+683721, with coordinates R.A. = 2.13947 deg, Decl. = +68.62279 deg (J2000; Petrov et al. 2008, AJ, 136, 580), and unknown redshift.
Preliminary analysis indicates that this source was in an elevated gamma-ray emission state on November 1, 2022, with a daily averaged gamma-ray flux (E>100MeV) of (1.7+/-0.3) X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only). This corresponds to approximately twice the flux observed at the time of its first detection (ATel #14089) and is the highest daily flux so far observed by Fermi from this source. The corresponding photon index is 2.2+/-0.1, and is consistent with the spectral index observed at the time of its previous detection. Using data collected by Fermi-LAT between October 27 00:00:00 UT and November 1 10:59:00 UT, the best fit localization is obtained at R.A. = 2.086 deg and Decl. = +68.579 deg, with a 95% confidence localization radius of 0.070 deg. This best fit localization, combined with a detection at R.A. = 2.125 deg, Decl. = +68.604 deg and 95% confidence radius of 0.027 deg between July 21 and August 20, 2021, supports the possible association with NVSS J000833+683721.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. We encourage multifrequency observations of this source. For this source, the Fermi-LAT contact person is Isabella Mereu (mereuisabella AT gmail DOT com).
The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
