# Fast Extragalactic X-ray Transients From Binary Neutron Star Mergers

## TL;DR

This paper investigates two extragalactic fast X-ray transients, XT1 and XT2, suggesting they originate from different astrophysical phenomena related to neutron star mergers, with implications for understanding transient populations.

## Contribution

It proposes that XT1 is an off-axis gamma-ray burst and XT2 is nebular emission from a neutron star merger, highlighting diverse origins of fast X-ray transients.

## Key findings

- XT1 is likely an off-axis gamma-ray burst.
- XT2 is probably nebular emission from a neutron star merger.
- These transients belong to different populations.

## Abstract

The observed light curves and other properties of the two extragalactic fast x-ray transients, CDF-S XT1 and CDF-S XT2, which were discovered recently in archival data of the Chandra Deep Field-South (CDF-S) observations, indicate that they belong to two different populations of X-ray transients. XT1 seems to be an x-ray flash (XRF), i.e., a narrowly beamed long duration gamma ray burst viewed from far off-axis while XT2 seems to be a nebular emission powered by a newly born millisecond pulsar in a neutron stars binary merger.