VERITAS observations of M87 from 2007 to present

TL;DR

This paper reports on VERITAS observations of M87 from 2007 onwards, highlighting the detection of high flux states and flares, and discusses the implications for understanding high-energy gamma-ray emission mechanisms in active galactic nuclei.

Contribution

It provides a comprehensive analysis of M87's TeV gamma-ray emission over several years, including multi-observatory campaigns and detection of rapid variability.

Findings

Detection of a high flux state in February 2008 with multiple flares

Observation of rapid variability in TeV gamma-ray emission

Preliminary results from the 2009 campaign

Abstract

M87 is a nearby radio galaxy and because of its misaligned jet, it is possible to correlate detailed spatially-resolved emission regions in the radio, optical to X-ray waveband with unresolved but contemporaneous flux measurements in the TeV regime. Hence, M87 provides a unique opportunity to reveal the emission mechanisms responsible for high energy gamma-ray emission from active galactic nuclei. Observations with VERITAS since 2007 have resulted in 90 hours of data while 2008 observations were part of a concerted effort involving the three major atmospheric Cherenkov observatories: H.E.S.S., MAGIC and VERITAS. As a result of the TeV campaign, a high flux state of M87 was detected in February 2008 showing multiple flares with rapid variability. We will present the comprehensive results from VERITAS observations since 2007 and also show preliminary results from the 2009 campaign.