MAGIC Upper Limits for two Milagro-detected, Bright Fermi Sources in the Region of SNR G65.1+0.6

TL;DR

This study used the MAGIC-I telescope to search for TeV gamma-ray emission from two bright Fermi sources near SNR G65.1+0.6, setting upper limits that suggest the emission is either extended or at higher energies.

Contribution

First MAGIC upper limits at TeV energies for two Fermi sources near SNR G65.1+0.6, constraining their gamma-ray emission characteristics.

Findings

No significant TeV emission detected by MAGIC.

Upper limits imply emission is extended or at higher energies.

Results constrain models of gamma-ray sources near SNR G65.1+0.6.

Abstract

We report on the observation of the region around supernova remnant G65.1+0.6 with the stand-alone MAGIC-I telescope. This region hosts the two bright GeV gamma-ray sources 1FGL J1954.3+2836 and 1FGL J1958.6+2845. They are identified as GeV pulsars and both have a possible counterpart detected at about 35 TeV by the Milagro observatory. MAGIC collected 25.5 hours of good quality data, and found no significant emission in the range around 1 TeV. We therefore report differential flux upper limits, assuming the emission to be point-like (<0.1 deg) or within a radius of 0.3 deg. In the point-like scenario, the flux limits around 1 TeV are at the level of 3 % and 2 % of the Crab Nebula flux, for the two sources respectively. This implies that the Milagro emission is either extended over a much larger area than our point spread function, or it must be peaked at energies beyond 1 TeV, resulting in a photon index harder than 2.2 in the TeV band.