NuSTAR view of the central region of M31

2018/01/15 by H. Stiele, A. K. H. Kong
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae #Physics #astro-ph.GA #astro-ph.HE

paper · pdf · doi:10.1093/mnras/sty106

14 pages, 8 figures, accepted by MNRAS

openalex publication_date 2018/01/15 · arxiv created 2018/01/30 · arxiv updated 2018/02/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

Our neighbouring large spiral galaxy, the Andromeda galaxy (M31 or NGC 224), is an ideal target to study the X-ray source population of a nearby galaxy. NuSTAR observed the central region of M31 in 2015 and allows studying the population of X-ray point sources at energies higher than 10 keV. Based on the source catalogue of the large XMM–Newton survey of M31, we identified counterparts to the XMM–Newton sources in the NuSTAR data. The NuSTAR data only contain sources of a brightness comparable (or even brighter) than the selected sources that have been detected in XMM–Newton data. We investigate hardness ratios, spectra, and long-term light curves of individual sources obtained from NuSTAR data. Based on our spectral studies, we suggest four sources as possible X-ray binary candidates. The long-term light curves of seven sources that have been observed more than once show low (but significant) variability.

Citations

• A Synoptic X‐Ray Study of M31 with theChandraHigh Resolution Camera
• A study of the population of LMXBs in the bulge of M 31
• Three X-ray transients in M 31 observed with Swift
• Tracing a Z-track in the M 31 X-ray binary RX J0042.6+4115
• The second ROSAT PSPC survey of M 31 and the complete ROSAT PSPC source list
• Supersoft X‐Ray Sources in M31. I. AChandraSurvey and an Extension to Quasi‐soft Sources