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arXiv · 2207.07674

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

Tomer Shenar·Hugues Sana·Laurent Mahy·Jesus Maiz Apellaniz·Paul A. Crowther·Mariusz Gromadzki·Artemio Herrero·Norbert Langer·Pablo Marchant·Fabian R. N. Schneider·Koushik Sen·Igor Soszynski·S. Toonen
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Abstract

We aim to hunt for massive binaries hosting a black hole companion (OB+BH) and establish the natal mass-ratio distribution of massive stars at the subsolar metallicity environment of the Large Magellanic Cloud (LMC). We use the shift-and-add grid disentangling technique to characterize the hidden companions in 51 SB1 O-type and evolved B-type binaries in the LMC monitored in the framework of the Tarantula Massive Binary Monitoring (TMBM). Out of the 51 SB1 systems, 43 (84%) are found to have non-degenerate stellar companions, of which 28 are confident detections, and 15 are less certain (SB1: or SB2:). Of these 43 targets, one is found to be a triple (VFTS 64), and two are found to be quadruples (VFTS 120, 702). The remaining eight targets (16%) retain an SB1 classification. Aside from the unambiguous case of VFTS 243, analysed in detailed in a separate paper, we identify two additional OB+BH candidates: VFTS 514 and VFTS 779. Additional black holes may be present in the sample but at a lower probability. Our study firmly establishes a virtually flat natal mass-ratio distribution for O-type stars at LMC metallicity, covering the entire mass-ratio range (0.05 < q < 1) and periods in the range 0 < log P < 3 [d]. The nature of the OB+BH candidates should be verified through future monitoring, but the frequency of OB+BH candidates is generally in line with recent predictions at LMC metallicity.

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Tomer Shenar, Hugues Sana, Laurent Mahy, Jesus Maiz Apellaniz, Paul A. Crowther, Mariusz Gromadzki, Artemio Herrero, Norbert Langer, Pablo Marchant, Fabian R. N. Schneider, Koushik Sen, Igor Soszynski, S. Toonen. 2022-07-15. 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. https://doi.org/10.1051/0004-6361%2F202244245

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