Updated radial velocities and new constraints on the nature of the unseen source in NGC1850 BH1

Abstract

A black hole candidate orbiting a luminous star in the Large Magellanic Cloud young cluster NGC 1850 ($\sim 100$Myr) has recently been reported based on radial velocity and light curve modelling. Subsequently, an alternative explanation has been suggested for the system: a bloated post-mass transfer secondary star (M${}_{\mathrm{initial}}\sim 4-5M_{\odot }$, M${}_{\mathrm{current}}\sim 1-2M_{\odot }$) with a more massive, yet luminous companion (the primary). Upon reanalysis of the MUSE spectra, we found that the radial velocity variations originally reported were underestimated ($K_{2,\mathrm{revised}}=176\pm 3$km/s vs $K_{2,\mathrm{original}}=140\pm 3$km/s) because of the weighting scheme adopted in the full-spectrum fitting analysis. The increased radial velocity semi-amplitude translates into a system mass function larger than previously deduced ($f_{\mathrm{revised}}$=2.83$M_{\odot }$ vs $f_{\mathrm{original}}$=1.42$M_{\odot }$). By exploiting the spectral disentangling technique, we place an upper limit of 10\% of a luminous primary source to the observed optical light in NGC1850 BH1, assuming that the primary and secondary are the only components contributing to the system. Furthermore, by analysing archival near-infrared data, we find clues to the presence of an accretion disk in the system. These constraints support a low-mass post-mass transfer star but do not provide a definitive answer whether the unseen component in NGC1850 BH1 is indeed a black hole. These results predict a scenario where, if a primary luminous source of mass M $\ge 4.7M_{\odot }$, is present in the system (given the inclination and secondary mass constraints), it must be hidden in a optically thick disk to be undetected in the MUSE spectra.

arXiv comment10 pages, 8 Figures and 2 Tables. Accepted for publication by MNRAS

References in corpus (26)

• Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• X-ray Properties of Black-Hole Binaries
• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• Neutron Star Structure and the Equation of State
• A Grid of NLTE Line-Blanketed Model Atmospheres of O-type Stars
• A Grid of NLTE Line-Blanketed Model Atmospheres of Early B-type Stars
• Classical Be Stars: Rapidly Rotating B Stars with Viscous Keplerian Decretion Disks
• BPASS predictions for Binary Black-Hole Mergers
• Spectral models for binary products: Unifying Subdwarfs and Wolf-Rayet stars as a sequence of stripped-envelope stars
• A wide star-black-hole binary system from radial-velocity measurements
• The Optical Light Curves of Cygnus X-2 (V1341 Cyg) and the Mass of its Neutron Star
• The 'hidden' companion in LB-1 unveiled by spectral disentangling
• MUSE crowded field 3D spectroscopy of over 12,000 stars in the globular cluster NGC 6397 - I. The first comprehensive spectroscopic HRD of a globular cluster
• Is HR 6819 a triple system containing a black hole? -- An alternative explanation
• A naked-eye triple system with a nonaccreting black hole in the inner binary
• Effects of close binary evolution on the main-sequence morphology of young star clusters
• No signature of the orbital motion of a putative 70 solar mass black hole in LB-1
• A stripped-companion origin for Be stars: clues from the putative black holes HR 6819 and LB-1
• The Tarantula Massive Binary Monitoring VI: Characterisation of hidden companions in 51 single-lined O-type binaries, a flat mass-ratio distribution, and black-hole binary candidates
• Double-periodic blue variables in the Magellanic Clouds
• Evidence for a physically bound third component in HD 150136
• The effects of stellar rotation along the main sequence of the 100 Myr old massive cluster NGC 1850
• A spectroscopic multiplicity survey of Galactic Wolf-Rayet stars. I. The northern WC sequence
• Fundamental parameters of the close interacting binary HD170582 and its luminous accretion disc
• To be or not to be a black hole: detailed binary population models as a sanity check

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• Binarity at Low Metallicity (BLOeM) -- Multiplicity properties of Oe and Be stars
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• Tracing the evolution of short-period binaries with super-synchronous fast rotators
• Binary properties of the globular cluster 47 Tuc (NGC 104). A dearth of short-period binaries
• Extreme mass ratios and fast rotation in three massive binaries
• Everything that glitters is not gold: V1315 Cas is not a dormant black hole
• Origin of High Dark Remnant Fractions in Milky Way Globular Clusters: The Crucial Role of Initial Black Hole Retention