[vsnet-grb-info 28463] Fermi-LAT Gamma-ray Observations of IceCube-210730A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30566
SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-210730A 
DATE:    21/07/31 19:49:50 GMT
FROM:    Sara Buson at GSFC/Fermi  <sara.buson at gmail.com>

S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg) and R. de Menezes (Univ. of Sao Paulo, Univ. of Wuerzburg) on behalf of the Fermi-LAT collaboration:
We report an analysis of observations of the vicinity of the high-energy IC210730A neutrino event (GCN 30559) 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 2021-07-30 at 22:12:40.629 UT (T0) with J2000 position RA = 105.73 (+2.00, -1.85) deg, Decl. = 14.79 (+0.91, -0.86) deg (90% PSF containment). One cataloged gamma-ray (>100 MeV) source is located within the 90% IC210730A localization region (4FGL-DR2, The Fermi-LAT collaboration 2020, ApJS, 247, 33). This is 4FGL J0659.7+1416, associated with the pulsar PSR J0659+1414 (Jankowski et al. 2019 MNRAS, 484, 3691). Based on a preliminary analysis of the LAT data over the timescale 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 IC210730A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC210730A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 5.1e-10 ph cm^-2 s^-1 for ~13-years (2008-08-04 to 2021-07-30 UTC), and < 2.7e-8 (< 1.6e-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 <http://desy.de/>) and S. Buson (sara.buson at uni-wuerzburg.de <http://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.