Very high energy Fermi/LAT detection of HESS J0632+057

TL;DR

This study reports the detection of HESS J0632+057 at very high energies (10-600 GeV) using Fermi/LAT over seven years, highlighting phase-dependent emission and spectral features with implications for understanding its emission mechanisms.

Contribution

First detection of HESS J0632+057 at energies above 80 GeV with Fermi/LAT, revealing phase-dependent emission and spectral break, advancing knowledge of this gamma-ray source.

Findings

Detection at 200-600 GeV with >3.6sigma significance during specific orbital phases.

No emission detected at lower energies or different phases.

Spectral break located above 80 GeV with a low-energy slope less than 2.0.

Abstract

We report on the results of ~7 yrs of the very-high energy (10-600 GeV) observations of HESS J0632+057 with FERMI/LAT. In the highest energy band, 200-600 GeV, the source is clearly detected with the statistical significance >3.6sigma at orbital phases 0.2-0.4 and 0.6-0.8 at which HESS J0632+057 is known to demonstrate enhanced emission in TeV energy band. The analysis did not reveal the emission from HESS J0632+057 at lower energies and different orbital phases. Using the upper limits on source's flux we locate the break of the spectrum to >80 GeV and low-energy slope <2.0 (2sigma statistical significance).