Survey of nearby active galactic nuclei with the HAWC Observatory

TL;DR

This paper reviews the use of the HAWC Observatory for surveying and monitoring nearby active galactic nuclei (AGNs) in TeV gamma rays, highlighting improvements in sensitivity and presenting search results.

Contribution

It provides a systematic survey of nearby AGNs using HAWC data, with enhanced low-energy sensitivity and new results on AGN monitoring.

Findings

Improved HAWC sensitivity at 100 GeV to 1 TeV based on Crab pulsar calibration.

Detection and monitoring of nearby AGNs in TeV gamma rays.

Insights into particle acceleration in AGN jets and photon propagation effects.

Abstract

The High Altitude Water Cherenkov Observatory (HAWC) has a wide field-of-view (FOV, $\sim$2sr) and a high duty cycle ($\sim$95\%), which make it a powerful survey and monitoring experiment for sources of TeV gamma rays. We present a systematic survey of gamma-ray sources based on the Fermi 3FHL catalog. Sources are restricted to HAWC's FOV (Declination 19$^\circ$ $\pm$ 40$^\circ$) and to extragalactic sources with redshift: 0.001 $<$ z $<$ 0.3. Extragalactic gamma-ray sources are dominated by active galactic nuclei (AGN) and TeV gamma-ray sources are mostly BL Lac-type blazars. The study of AGNs through high energy gamma rays has opened a new window into the extreme processes of particle acceleration in the jets of these objects and provides a way to study the photon propagation and extra-galactic background light. We have improved the HAWC sensitivity at low energies (100 GeV to 1 TeV) based on the Crab pulsar, which is an excellent calibration source for TeV gamma rays. We will present the results of searching for and monitoring nearby AGNs with the improved analysis.