Facial reconstruction

Search LJMU Research Online

Browse Repository | Browse E-Theses

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

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

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
Open Access URL: https://doi.org/10.1093/mnras/stad764 (Published version)


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
View Item View Item