Ultraluminous X-ray Sources in Seven Edge-On Spiral Galaxies

TL;DR

This study uses Chandra X-ray observations of seven edge-on spiral galaxies to identify and analyze ultraluminous X-ray sources, revealing their typical locations and transient nature, which informs understanding of their origins.

Contribution

It provides the first detailed analysis of ULXs in edge-on spiral galaxies, highlighting their prevalence in central regions and identifying transient ULXs for further study.

Findings

12 candidate ULXs identified after removing contaminants

Most ULXs are located in the central disk/bulge regions

Detection of two transient ULXs suggesting diverse source types

Abstract

We investigate a sample of seven edge-on spiral galaxies using Chandra observations. Edge-on spiral galaxies allow us to clearly separate source associated with their star-forming regions versus the outer edges of the system; offering a clear advantage over other systems. We uncover a number of X-ray point sources across these galaxies, and after eliminating contaminating foreground and background sources, we identify 12 candidate ultraluminous X-ray sources. All of these sources are projected onto the central regions, implying that the majority of ULXs in this sample of spiral galaxies are disk/bulge, and thus not halo sources. This also includes two transient ULXs, which may be long-duration transients and low mass X-ray binaries. This finding illustrates the need for further studies of transient ULXs.