GCN Circular 29473
Subject
Fermi-LAT Gamma-ray Observations of IceCube-210210A
Date
2021-02-11T09:21:35Z (4 years ago)
From
Simone Garrappa at DESY <simone.garrappa@desy.de>
S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg), C. C. Cheung
(NRL) on behalf of the Fermi-LAT collaboration:
We report an analysis of observations of the vicinity of the high-energy
IC210210A neutrino event (GCN 29454) with all-sky survey data from the
Large Area Telescope (LAT), on board the Fermi Gamma-ray Space
Telescope. The IceCube event was detected on 2021-02-10 at 11:53:55.65
UT (T0) with J2000 position RA = 206.06 (+1.40, -0.95) deg, Decl. = 4.78
(+0.62, -0.56) deg (90% PSF containment). One cataloged >100 MeV
gamma-ray source is located within the 90% IC200210A localization
region. This is 4FGL J1342.7+0505 (4FGL, The Fermi-LAT collaboration
2020, ApJS, 247, 33), associated with 4C +05.57 (Pilkington and Scott
1965, MmRAS, 69, 183), a.k.a., PKS 1340+05 (Bolton et al. 1975 Aust.J.
Phys. Astrophys. SuppL, No. 34, 1), at redshift z = 0.13663 (Hewett and
Wild, 2010, MNRAS, 405, 2302). PKS 1340+05 has been classified
spectroscopically as a BL Lac (BL Lac galaxy-dominated, de Menezes et al
2019, A&A 630, A55) and broad-line radio galaxy (Grandi 1983, MNRAS,
204, 691). Based on a preliminary analysis of the LAT data over the
timescales of 1-day and 1-month prior to T0, this object is not
significantly detected (> 5 sigma).
We searched for intermediate (days to years) timescale emission from a
new gamma-ray transient source. Preliminary analysis indicates no
significant (> 5 sigma) new excess emission (> 100 MeV) at the IC210210A
best-fit position. Assuming a power-law spectrum (photon index = 2.0
fixed) for a point source at the IC210210A best-fit position, the >100
MeV flux upper limit (95% confidence) is < 6.1e-10 ph cm^-2 s^-1 for
~12-years (2008-08-04 to 2021-02-10 UTC), and < 9.8e-9 (< 1e-7) ph cm^-2
s^-1 for a 1-month (1-day) integration time before T0.
Since Fermi normally operates in an all-sky scanning mode, regular
monitoring of this source will continue. For these observations the
Fermi-LAT contact persons are S. Garrappa (simone.garrappa at desy.de)
and S. Buson (sara.buson at uni-wuerzburg.de).
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.