A Population of Neutron Star Ultraluminous X-ray Sources with A Helium Star Companion

Abstract

It was recently proposed that a significant fraction of ultraluminous X-ray sources (ULXs) actually host a neutron star (NS) accretor. We have performed a systematic study on the NS ULX population in Milky Way-like galaxies, by combining binary population synthesis and detailed stellar evolution calculations. Besides a normal star, the ULX donor can be a helium star (the hydrogen envelope of its progenitor star was stripped during previous common envelope evolution) if the NS is accreting at a super-Eddington rate via Roche lobe overflow. We find that the NS$-$helium star binaries can significantly contribute the ULX population, with the overall number of about several in a Milky Way-like galaxy. Our calculations show that such ULXs are generally close systems with orbital period distribution peaked at $\sim 0.1$ day (with a tail up to $\sim 100$ days), and the helium stars have relatively low masses distributing with a maximum probability at $\sim 1M_{\odot }$.

9 pages, 7 figures, accepted by ApJ

References in corpus (24)

• Modules for Experiments in Stellar Astrophysics (MESA)
• An Ultraluminous X-ray Source Powered by An Accreting Neutron Star
• Super-critically accreting stellar-mass black holes as ultraluminous X-ray sources
• An accreting pulsar with extreme properties drives an ultraluminous x-ray source in NGC 5907
• Discovery of a 0.42-s pulsar in the ultraluminous X-ray source NGC 7793 P13
• Discovery of coherent pulsations from the Ultraluminous X-ray Source NGC 7793 P13
• Post-common-envelope binaries from SDSS. IX: Constraining the common-envelope efficiency
• A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source
• A 400 solar mass black hole in the Ultraluminous X-ray source M82 X-1 accreting close to its Eddington limit
• Masses, Beaming and Eddington Ratios in Ultraluminous X-ray Sources
• The discovery of weak coherent pulsations in the ultraluminous X-ray source NGC 1313 X-2
• On the formation of Be stars through binary interaction
• Pulsing ULXs: tip of the iceberg?
• The ultra luminous X-ray source NuSTAR J095551+6940.8: A magnetar in a high mass X-ray binary
• NuSTAR J095551+6940.8: a highly magnetised neutron star with super-Eddington mass accretion
• An ultraluminous nascent millisecond pulsar
• A Population of Ultraluminous X-ray Sources with An Accreting Neutron Star
• Near-infrared counterparts of ultraluminous X-ray sources
• On the Formation of Ultraluminous X-ray Sources with Neutron Star Accretors: the Case of M82 X-2
• New Hubble Space Telescope imaging of the counterparts to six ultraluminous X-ray sources
• An accreting low magnetic field magnetar for the ultraluminous X-ray source in M82
• Nonconservative Mass Transfer in Massive Binaries and the Formation of Wolf-Rayet+O Binaries
• Searching for the Donor Stars of ULX Pulsars
• Constraining the dipolar magnetic field of M82 X-2 by the accretion model

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• The impact of mass-transfer physics on the observable properties of field binary black hole populations
• Binary Black Hole Formation with Detailed Modeling: Stable Mass Transfer Leads to Lower Merger Rates
• Population Synthesis of Black Hole X-Ray Binaries
• Ultra-compact X-ray binaries with He star companions
• Multi-messenger-Athena Synergy White Paper
• A pulsar-helium star compact binary system formed by common envelope evolution
• Identification of a Helium Donor Star in NGC 247 ULX-1
• X-ray emission from helium star+black hole binaries as probes of tidally induced spin-up of second-born black holes
• Ultraluminous X-ray sources with He star companions
• Populations of ultraluminous X-ray sources in galaxies: origin and evolution