Discovery of a dormant 33 solar-mass black hole in pre-release Gaia astrometry

Author(s): , P. Panuzzo, T. Mazeh, F. Arenou, B. Holl, E. Caffau, A. Jorissen, C. Babusiaux, P. Gavras, J. Sahlmann, U. Bastian, L. Wyrzykowski, L. Eyer, N. Leclerc, N. Bauchet, A. Bombrun, N. Mowlavi, G. M. Seabroke, D. Teyssier, E. Balbinot, A. Helmi, A. G.A. Brown, A. Vallenari, T. Prusti, J. H.J. De Bruijne, A. Barbier, M. Biermann, O. L. Creevey, C. Ducourant, D. W. Evans, C. Aerts, M. Altmann, D. Hestroffer, M. Schultheis, M. Smith, P. Ábrahám, S. Ahmed, F. Anders, P. Charlot, M. Crosta, T. Lebzelter, R. G. Mann, L. Molnár, A. Riva, H. W. Rix, M. Semczuk, J. Souchay, L. Szabados, M. B. Taylor, N. Unger, M. Weiler
Abstract: Context. Gravitational waves from black-hole (BH) merging events have revealed a population of extra-galactic BHs residing in short-period binaries with masses that are higher than expected based on most stellar evolution models-And also higher than known stellar-origin black holes in our Galaxy. It has been proposed that those high-mass BHs are the remnants of massive metal-poor stars. Aims. Gaia astrometry is expected to uncover many Galactic wide-binary systems containing dormant BHs, which may not have been detected before. The study of this population will provide new information on the BH-mass distribution in binaries and shed light on their formation mechanisms and progenitors. Methods. As part of the validation efforts in preparation for the fourth Gaia data release (DR4), we analysed the preliminary astrometric binary solutions, obtained by the Gaia Non-Single Star pipeline, to verify their significance and to minimise false-detection rates in high-mass-function orbital solutions. Results. The astrometric binary solution of one source, Gaia BH3, implies the presence of a 32.70a ±a 0.82aM- BH in a binary system with a period of 11.6 yr. Gaia radial velocities independently validate the astrometric orbit. Broad-band photometric and spectroscopic data show that the visible component is an old, very metal-poor giant of the Galactic halo, at a distance of 590 pc. Conclusions. The BH in the Gaia BH3 system is more massive than any other Galactic stellar-origin BH known thus far. The low metallicity of the star companion supports the scenario that metal-poor massive stars are progenitors of the high-mass BHs detected by gravitational-wave telescopes. The Galactic orbit of the system and its metallicity indicate that it might belong to the Sequoia halo substructure. Alternatively, and more plausibly, it could belong to the ED-2 stream, which likely originated from a globular cluster that had been disrupted by the Milky Way.
Organisation(s): Department of Astrophysics
External organisation(s): Paris Observatory, Tel Aviv University, Université de Genève, Université Libre de Bruxelles, University of Grenoble Alpes, European Space Astronomy Centre (ESA), Scientific Software Center, University of Warsaw, University College London, University of Groningen, Leiden University, Osservatorio Astronomico, Science and Operations Department - Science Division (SCI-SC), Centre national d'études spatiales (CNES), Université Côte d'Azur, Laboratoire d'Astrophysique de Bordeaux, University of Cambridge, Katholieke Universiteit Leuven, Radboud University, Max-Planck-Institut für Astronomie, Université de recherche Paris Sciences et Lettres, Hungarian Academy of Sciences, Eötvös Loránd University Budapest, HUN-REN Hungarian Research Network, University of Barcelona, Institute of Space Studies of Catalonia (IEEC), INAF-Osservatorio Astrofisico di Torino, University of Turin, Centre de Recherche en Astronomie Astrophysique et Géophysique, University of Bristol
Journal: Astronomy and Astrophysics
Volume: 686
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202449763
Publication date: 05-2024
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy
Keywords
ASJC Scopus subject areas: Astronomy and Astrophysics, Space and Planetary Science
Portal url: https://ucrisportal.univie.ac.at/en/publications/b9671dc3-f858-413a-ad1d-59ba54c121ab

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