LB-1 is inconsistent with the X-ray source population and pulsar-black hole binary searches in the Milky Way

Abstract

If confirmed, a wide binary system of 70 $M_{\odot }$ black hole (BH) and an 8 $M_{\odot }$ main sequence star (LB-1) is observed to reside in the Milky Way (MW). We show that long term evolution of an 8 $M_{\odot }$ star around a BH with mass between 5-70 $M_{\odot }$ makes them visible as ultra-luminous X-ray (ULX) sources in the sky. Given the expected ULX phase lifetime ($\approx 0.1$ Myr) and their lack of detection in the MW, we conclude that the frequency of an 8-20 $M_{\odot }$ star to be in binary around a stellar mass BH should be less than ($f<2\times 10^{-3}$). This is in tension with Liu et al. (2019) claimed detection frequency of LB-1 like system around 8-20$M_{\odot }$ stars ($f\approx 3\times 10^{-2}$). Moreover, the 8 $M_{\odot }$ star is likely to end as a neutron star (NS) born with a very small kick from an electron capture supernova (ECSN), leaving behind a wide NS-BH binary. So far less than 1\% of all the detectable pulsars in the MW are mapped and there has been no detection of any pulsars in binary systems around BHs which sets an upper bound of about 100 possible pulsar-BH systems in the MW. We show if the NS is born from ECSN, a frequency upper limit of ($f=5\times 10^{-4}$) for stars with masses $\approx 8-20M_{\odot }$ in the MW to have a BH companion. The rate discrepancy will further increase as more pulsars are mapped in the MW, yet these searches would not be able to rule out the Liu et al. detection frequency if NSs are instead born in core collapse SNe with the commonly inferred high kick velocities.

arXiv commentAccepted for publication in ApJ

References in corpus (30)

• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• A statistical study of 233 pulsar proper motions
• Compact Object Modeling with the StarTrack Population Synthesis Code
• Pulsational Pair-Instability Supernovae
• Formation of Double Neutron Star Systems
• The Relation Between Optical Extinction and Hydrogen Column Density in the Galaxy
• Binary and Millisecond Pulsars
• Improved Estimates of the Milky Way's Stellar Mass and Star Formation Rate from Hierarchical Bayesian Meta-Analysis
• A Geometric Determination of the Distance to the Galactic Center
• The Milky Way in X-rays for an outside observer: Log(N)-Log(S) and Luminosity Function of X-ray binaries from RXTE/ASM data
• The White Dwarf Initial-Final Mass Relation for Progenitor Stars From 0.85 to 7.5 M${}_{\odot }$
• Global properties of the HI distribution in the outer Milky Way
• Grand Unification in Neutron Stars
• A wide star-black-hole binary system from radial-velocity measurements
• Spin-down Measurement of PSR J1852+0040 in Kesteven 79: Central Compact Objects as Anti-Magnetars
• Neutron star kicks by the gravitational tug-boat mechanism in asymmetric supernova explosions: progenitor and explosion dependence
• Hydrodynamical Neutron-star Kicks in Electron-capture Supernovae and Implications for the CRAB Supernova
• Neutrino-driven explosions of ultra-stripped type Ic supernovae generating binary neutron stars
• Synthetic catalog of black holes in the Milky Way
• Comparing Neutron Star Kicks to Supernova Remnant Asymmetries
• Not so fast: LB-1 is unlikely to contain a 70 $M_{\odot }$ black hole
• The Evolution and Properties of Rotating Massive Star Populations
• No signature of the orbital motion of a putative 70 solar mass black hole in LB-1
• The Edge of the Milky Way Stellar Disk Revealed Using Clump Giant Stars as Distance Indicators
• The Formation of a 70 Msun Black Hole at High Metallicity
• Weighing in on black hole binaries with BPASS: LB-1 does not contain a 70M${}_{\odot }$ black hole
• Pulsar Binary Birthrates with Spin-Opening Angle Correlations
• The connection between merging double compact objects and the Ultraluminous X-ray Sources
• Searching for Millisecond Pulsars: Surveys, Techniques and Prospects
• Constraints on the binary black hole hypothesis for system LB-1

Cited by in corpus (3)

• Search for a Black Hole Binary in Gaia DR3 Astrometric Binary Stars with Spectroscopic Data
• Non-interacting black hole binaries with Gaia and LAMOST
• Detectablity of Black Hole Binaries with Gaia: Dependence on Binary Evolution Models