A new candidate Wolf-Rayet X-ray binary in NGC 253

Abstract

We have discovered a persistent, but highly variable X-ray source in the nearby starburst galaxy NGC 253. The source varies at the level of a factor of about 5 in count rate on timescales of a few hours. Two long observations of the source with Chandra and XMM-Newton show suggestive evidence for the source having a period of about 14-15 hours, but the time sampling in existing data is insufficient to allow a firm determination that the source is periodic. Given the amplitude of variation and the location in a nuclear starburst, the source is likely to be a Wolf-Rayet X-ray binary, with the tentative period being the orbital period of the system. In light of the fact that we have demonstrated that careful examination of the variability of moderately bright X-ray sources in nearby galaxies can turn up candidate Wolf-Rayet X-ray binaries, we discuss the implications of Wolf-Rayet X-ray binaries for predictions of the gravitational wave source event rate, and, potentially, interpretations of the events.

9 pages, 3 figures, accepted to MNRAS

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Cited by in corpus (14)

• The Evolution of Compact Binary Star Systems
• Spatially Resolving a Starburst Galaxy at Hard X-ray Energies: NuSTAR, Chandra, AND VLBA Observations of NGC 253
• Revisiting the Dynamical Case for a Massive Black Hole in IC10 X-1
• Gemini/GNIRS infrared spectroscopy of the Wolf-Rayet stellar wind in Cygnus X-3
• Outflows from Super Star Clusters in the Central Starburst of NGC253
• Periodic signals from the Circinus region: two new cataclysmic variables and the ultraluminous X-ray source candidate GC X-1
• dart_board: Binary Population Synthesis with Markov Chain Monte Carlo
• CG X-1: an eclipsing Wolf-Rayet ULX in the Circinus galaxy
• Formation of Black Hole Low-Mass X-ray Binaries
• The Next Generation X-ray Galaxy Survey with eROSITA
• The First Candidate Colliding-Wind Binary in M33
• Progenitor constraints for core-collapse supernovae from Chandra X-ray observations
• Peculiar outbursts of an ultra luminous source likely signs of an aperiodic disc-wind
• Monitoring of the eclipsing Wolf-Rayet ULX in the Circinus galaxy