VERITAS Upper Limit on the VHE Emission from the Radio Galaxy NGC 1275

TL;DR

This paper reports a VERITAS observation of NGC 1275, setting an upper limit on its very high energy gamma-ray emission, which constrains models of gamma-ray production in misaligned active galactic nuclei.

Contribution

It provides the first VHE upper limit for NGC 1275, complementing Fermi-LAT observations and informing models of gamma-ray emission in radio galaxies.

Findings

No VHE gamma-ray emission detected by VERITAS.

Established a 99% confidence upper limit of 2.1% of the Crab flux.

Upper limit constrains theoretical models of gamma-ray emission.

Abstract

The recent detection by the Fermi gamma-ray space telescope of high-energy gamma-rays from the radio galaxy NGC 1275 makes the observation of the very high energy (VHE: E > 100 GeV) part of its broadband spectrum particularly interesting, especially for the understanding of active galactic nuclei (AGN) with misaligned multi-structured jets. The radio galaxy NGC 1275 was recently observed by VERITAS at energies above 100 GeV for about 8 hours. No VHE gamma-ray emission was detected by VERITAS from NGC 1275. A 99% confidence level upper limit of 2.1% of the Crab Nebula flux level is obtained at the decorrelation energy of approximately 340 GeV, corresponding to 19% of the power-law extrapolation of the Fermi Large Area Telescope (LAT) result.