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Saracino, S, Shenar, T, Kamann, S, Bastian, N, Gieles, M, Usher, C, Bodensteiner, J, Kochoska, A, Orosz, JA and Sana, H (2023) Updated radial velocities and new constraints on the nature of the unseen source in NGC1850 BH1. Monthly Notices of the Royal Astronomical Society, 521 (2). pp. 3162-3171. ISSN 0035-8711
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Updated radial velocities and new constraints on the nature of the unseen source in NGC1850 BH1.pdf - Published Version Available under License Creative Commons Attribution. Download (1MB) | Preview |
Abstract
A black hole candidate orbiting a luminous star in the Large Magellanic Cloud young cluster NGC 1850 (∼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 (Minitial ∼ 4–5 M⊙ and Mcurrent ∼ 1–2 M⊙) 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 (K2, revised = 176 ± 3 km s−1 versus K2, original = 140 ± 3 km s−1) 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 (frevised = 2.83 M⊙versus foriginal = 1.42 M⊙). By exploiting the spectral disentangling technique, we place an upper limit of 10 per cent 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 disc 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 ≥ 4.7 M⊙ is present in the system (given the inclination and secondary mass constraints), it must be hidden in a optically thick disc to be undetected in the MUSE spectra.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | astro-ph.GA; astro-ph.GA; astro-ph.SR |
| Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
| Divisions: | Astrophysics Research Institute |
| Publisher: | Oxford University Press |
| Related URLs: | |
| SWORD Depositor: | A Symplectic |
| Date Deposited: | 24 Mar 2023 19:17 |
| Last Modified: | 25 Mar 2023 08:00 |
| DOI or ID number: | 10.1093/mnras/stad764 |
| URI: | https://researchonline.ljmu.ac.uk/id/eprint/19164 |
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