Fermi-LAT Gamma-ray Follow up Observations of AGL J2233-2212 (within 90% PSF containment of IceCube-190331A)
ATel #12624; S. Buson (Univ. of Wuerzburg, UMBC) and S. Garrappa (DESY-Zeuthen) on behalf of the Fermi-LAT collaboration
on 2 Apr 2019; 17:46 UT
Credential Certification: Sara Buson (sara.buson@gmail.com)
Subjects: Gamma Ray, Neutrinos, Transient
Referred to by ATel #: 12627
The AGILE collaboration reported the detection of significant (4sigma) gamma-ray emission from AGL J2233-2212 (ATEL #12623), a new transient positionally consistent with the IceCube neutrino IC190331A. The reported flux is F(E>100 MeV)=(2.2 +/- 0.9) x 10^-6 ph cm^-2 s^-1, when integrating a 3-day time interval from 2019-03-30 05:00 UT to 2019-04-02 05:00 UT.
We have searched the Fermi-LAT data for gamma-ray emission from this new transient. Assuming a single power-law spectrum for a putative source at the same location of AGL J2233-2212, i.e. R.A., Decl. (J2000) = (338.3 deg, -22.2 deg), integrating from 2019-03-30 05:00 UT to 2019-04-02 05:00 UT, a preliminary analysis (E>100MeV) does not find evidence for significant (>1sigma) point-source gamma-ray emission. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the AGL J2233-2212 best-fit position, the >100 MeV flux upper limit (95% confidence) is <1.9e-8 ph cm^-2 s^-1.
Because Fermi normally operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. For this source the Fermi-LAT contact persons are Sara Buson (sara.buson at astro.uni-wuerzburg.edu) and Simone Garrappa (simone.garrappa at desy.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.
