A First Look at Periodicity in HAWC with TeV Binaries

TL;DR

This paper investigates periodic TeV gamma-ray emission from binary systems using HAWC data, aiming to understand their emission mechanisms and the nature of their compact objects through a stacking analysis of 760 days of observations.

Contribution

It introduces a stacking analysis method applied to HAWC data to enhance detection of TeV binaries and explores their orbital emission characteristics.

Findings

No significant periodic TeV emission detected yet.

Method improves sensitivity to faint TeV signals.

Provides constraints on TeV emission timing in binaries.

Abstract

Only five binary systems have been found to emit at TeV energies. Each of these systems is composed of a massive O or B type star and a compact object (black hole or a pulsar). The type of compact object and the origin of the gamma-ray emission is unknown for most of these systems. Extending spectral observations to higher energies can help disentangle the nature of the compact object as well as the particle acceleration mechanisms present. Interestingly, the TeV emission from these systems does not always coincide with their emission in GeV or X-ray, which is how many such systems have been originally discovered. Increased coverage of these systems may allow HAWC to see precisely when in the orbit the TeV emission begins and ends. The HAWC Observatory detects TeV gamma-rays with high sensitivity, covering over two-thirds of the overhead sky every day. Applying a stacking method to known TeV binary systems can help HAWC enhance the signal from TeV binaries above the steady background from other sources in the galaxy. We will present results from this stacking analysis using 760 days of HAWC data.