Fermi-LAT gamma-ray observations of SN 2023ixf
ATel #16075; G. Marti-Devesa (University of Innsbruck), on behalf of the Fermi-LAT Collaboration
on 6 Jun 2023; 13:26 UT
Credential Certification: Teddy Cheung (Teddy.Cheung@nrl.navy.mil)
Subjects: Gamma Ray, >GeV, Supernovae
We report an analysis of SN 2023ixf with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. The SN 2023ixf was initially reported by K. Itagaki in M101 on May 19 (T0 = 2023-05-19 17:27:15 UTC) and later classified as a Type II SN (Perley et al., AstroNote 2023-119). Since then, it has been monitored at several wavelengths (e.g. ATels #16045, #16047, #16049, #16052, #16073) and neutrino limits have been provided (ATels #16043, #16070).
We searched for emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (> 5 sigma) new excess emission (> 100 MeV) at the optical position of SN 2023ixf (TNS). Assuming a power-law spectrum (photon index = 2.0, fixed) for a point source at the SN 2023ixf nominal position, the >100 MeV flux upper limit (95% confidence) is < 1.9e-8 ph cm^-2 s^-1 (< 2.6e-11 erg cm^-2 s^-1) for a 14-day integration time after its discovery (2023-05-19 17:27:15 to 2023-06-02 17:27:15 UTC). This corresponds to a luminosity limit of < 1.3e41 erg s^-1 for a distance of 6.4 Mpc. No signal with larger fluence is detected either on shorter time scales (from T0 to T0+1, T0+5, or T0+12 days). This limit is about one order of magnitude above the hard X-ray luminosity reported by NuSTAR, which has a power-law index of 1.3 (ATel #16049).
Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this region will continue. For this source the Fermi-LAT contact person is Guillem Marti-Devesa (guillem.marti-devesa@uibk.ac.at).
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.
