Letter to the Editor

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

¹ GEPI, Observatoire de Paris, Université PSL, CNRS, 5 Place Jules Janssen, 92190 Meudon, France
e-mail: pasquale.panuzzo@observatoiredeparis.psl.eu
² School of Physics and Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel
³ Department of Astronomy, University of Geneva, Chemin Pegasi 51, 1290 Versoix, Switzerland
⁴ Department of Astronomy, University of Geneva, Chemin d’Ecogia 16, 1290 Versoix, Switzerland
⁵ Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles CP 226, Boulevard du Triomphe, 1050 Brussels, Belgium
⁶ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
⁷ RHEA for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁸ Astronomisches Rechen-Institut, Zentrum fr Astronomie der Universitt Heidelberg, Mnchhofstr. 12-14, 69120 Heidelberg, Germany
⁹ Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
¹⁰ HE Space Operations BV for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
¹¹ Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
¹² Telespazio UK S.L. for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
¹³ Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands
¹⁴ Leiden Observatory, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
¹⁵ INAF – Osservatorio astronomico di Padova, Vicolo Osservatorio 5, 35122 Padova, Italy
¹⁶ European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
¹⁷ CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
¹⁸ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire, CS 34229, 06304 Nice Cedex 4, France
¹⁹ Laboratoire d’astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
²⁰ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
²¹ European Space Agency (ESA), European Space Astronomy Centre (ESAC), Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
²² Aurora Technology for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
²³ Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (UB), Martí i Franquès 1, 08028 Barcelona, Spain
²⁴ Institut d’Estudis Espacials de Catalunya (IEEC), c. Esteve Terradas 1, 08860 Castelldefels, (Barcelona), Spain
²⁵ Lohrmann Observatory, Technische Universitt Dresden, Mommsenstraße 13, 01062 Dresden, Germany
²⁶ Lund Observatory, Division of Astrophysics, Department of Physics, Lund University, Box 43, 22100 Lund, Sweden
²⁷ Departament de Física Quàntica i Astrofísica (FQA), Universitat de Barcelona (UB), c. Martí i Franquès 1, 08028 Barcelona, Spain
²⁸ INAF – Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy
²⁹ Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716 Warsaw, Poland
³⁰ Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
³¹ Department of Astrophysics/IMAPP, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands
³² Max Planck Institute for Astronomy, Knigstuhl 17, 69117 Heidelberg, Germany
³³ INAF – Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese, (TO), Italy
³⁴ European Space Agency (ESA, retired), European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
³⁵ University of Turin, Department of Physics, Via Pietro Giuria 1, 10125 Torino, Italy
³⁶ Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium
³⁷ DAPCOM Data Services, c. dels Vilabella, 5-7, 80500 Vic, Barcelona, Spain
³⁸ Observational Astrophysics, Division of Astronomy and Space Physics, Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
³⁹ ALTEC S.p.a, Corso Marche, 79, 10146 Torino, Italy
⁴⁰ Sednai Sàrl, Geneva, Switzerland
⁴¹ Gaia DPAC Project Office, ESAC, Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁴² SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, 61 avenue de l’Observatoire, 75014 Paris, France
⁴³ IMCCE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Univ. Lille, 77 av. Denfert-Rochereau, 75014 Paris, France
⁴⁴ INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy
⁴⁵ Serco Gestión de Negocios for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁴⁶ Institut d’Astrophysique et de Géophysique, Université de Liège, 19c, Allée du 6 Août, 4000 Liège, Belgium
⁴⁷ CRAAG – Centre de Recherche en Astronomie, Astrophysique et Géophysique, Route de l’Observatoire Bp 63, Bouzareah, 16340 Algiers, Algeria
⁴⁸ Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
⁴⁹ CIGUS CITIC – Department of Computer Science and Information Technologies, University of A Coruña, Campus de Elviña s/n, A Coruña 15071, Spain
⁵⁰ Kavli Institute for Cosmology Cambridge, Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK
⁵¹ Department of Astrophysics, Astronomy and Mechanics, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, 15783 Athens, Greece
⁵² Donald Bren School of Information and Computer Sciences, University of California, Irvine, CA 92697, USA
⁵³ CENTRA, Faculdade de Ciências, Universidade de Lisboa, Edif. C8, Campo Grande, 1749-016 Lisboa, Portugal
⁵⁴ INAF – Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania, Italy
⁵⁵ Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università di Catania, Via S. Sofia 64, 95123 Catania, Italy
⁵⁶ Université de Strasbourg, CNRS, Observatoire astronomique de Strasbourg, UMR 7550, 11 rue de l’Université, 67000 Strasbourg, France
⁵⁷ INAF – Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monte Porzio Catone, (Roma), Italy
⁵⁸ Space Science Data Center – ASI, Via del Politecnico SNC, 00133 Roma, Italy
⁵⁹ Department of Physics, University of Helsinki, PO Box 64, 00014 Helsinki, Finland
⁶⁰ Finnish Geospatial Research Institute FGI, Vuorimiehentie 5, 02150 Espoo, Finland
⁶¹ Institut UTINAM CNRS UMR6213, Université de Franche-Comté, OSU THETA Franche-Comté Bourgogne, Observatoire de Besançon, BP1615, 25010 Besançon Cedex, France
⁶² HE Space Operations BV for European Space Agency (ESA), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
⁶³ Dpto. de Inteligencia Artificial, UNED, c/ Juan del Rosal 16, 28040 Madrid, Spain
⁶⁴ Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
⁶⁵ Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, MTA Centre of Excellence, 1121 Konkoly Thege Miklós út 15-17, Budapest, Hungary
⁶⁶ Institute of Physics and Astronomy, ELTE Etvs Loránd University, 1117 Pázmány Péter sétány 1A, Budapest, Hungary
⁶⁷ University of Vienna, Department of Astrophysics, Türkenschanzstraße 17, A1180 Vienna, Austria
⁶⁸ ATG Europe for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada 28692 Madrid, Spain
⁶⁹ Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland
⁷⁰ Centre for Astrophysics Research, University of Hertfordshire, College Lane, AL10 9AB Hatfield, UK
⁷¹ Quasar Science Resources for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
⁷² LASIGE, Faculdade de Ciências, Universidade de Lisboa, Edif. C6, Campo Grande, 1749-016 Lisboa, Portugal
⁷³ School of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK
⁷⁴ Astrophysics Group, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK
⁷⁵ Thales Services for CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
⁷⁶ Telespazio for CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
⁷⁷ National Observatory of Athens, I. Metaxa and Vas. Pavlou, Palaia Penteli, 15236 Athens, Greece
⁷⁸ University of Maryland, College Park, MD, USA
⁷⁹ EURIX S.r.l., Corso Vittorio Emanuele II 61, 10128 Torino, Italy
⁸⁰ Porter School of the Environment and Earth Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
⁸¹ Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS 15, Cambridge, MA 02138, USA
⁸² Laboratoire de Recherche en Neuroimagerie, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
⁸³ Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney, NSW 2006, Australia
⁸⁴ ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Mt. Stromlo, Australia
⁸⁵ ATOS for CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
⁸⁶ Department of Physics and Astronomy G. Galilei, University of Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
⁸⁷ LFCA/DAS,Universidad de Chile, CNRS, Casilla 36-D, Santiago, Chile
⁸⁸ University of West Attica, Ag. Spyridonos Str., Egaleo, 12243 Athens, Greece
⁸⁹ SISSA – Scuola Internazionale Superiore di Studi Avanzati, via Bonomea 265, 34136 Trieste, Italy
⁹⁰ SII for CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
⁹¹ University of Turin, Department of Computer Sciences, Corso Svizzera 185, 10149 Torino, Italy
⁹² Dpto. de Matemática Aplicada y Ciencias de la Computación, Univ. de Cantabria, ETS Ingenieros de Caminos, Canales y Puertos, Avda. de los Castros s/n, 39005 Santander, Spain
⁹³ Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra, (Barcelona), Spain
⁹⁴ Port d’Informació Científica (PIC), Campus UAB, C. Albareda s/n, 08193 Bellaterra, (Barcelona), Spain
⁹⁵ Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Avenida Complutense 40, 28040 Madrid, Spain
⁹⁶ Monash University, 10 College Walk, Monash University, Clayton, VIC 3800, Australia
⁹⁷ Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
⁹⁸ Universidad Andres Bello, Facultad de Ciencias Exactas, Departamento de Ciencias Físicas – Instituto de Astrofísica, Fernandez Concha 700, Las Condes, Santiago, Chile
⁹⁹ LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, 5 Place Jules Janssen, 92190 Meudon, France
¹⁰⁰ University of Turin, Mathematical Department “G.Peano”, Via Carlo Alberto 10, 10123 Torino, Italy
¹⁰¹ University of Antwerp, Onderzoeksgroep Toegepaste Wiskunde, Middelheimlaan 1, 2020 Antwerp, Belgium
¹⁰² INAF – Osservatorio Astronomico d’Abruzzo, Via Mentore Maggini, 64100 Teramo, Italy
¹⁰³ APAVE EXPLOITATION for CNES Centre Spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France
¹⁰⁴ Dpto. Física Teórica y del Cosmos, Universidad de Granada, 18071 Granada, Spain
¹⁰⁵ The Center for Cosmology and Particle Physics, New York University, 726 Broadway, New York, NY 10003, USA
¹⁰⁶ Finnish Centre for Astronomy with ESO, University of Turku, 20014 Turku, Finland
¹⁰⁷ Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN, UK
¹⁰⁸ Institute for Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE, UK
¹⁰⁹ Data Science and Big Data Lab, Pablo de Olavide University, 41013 Seville, Spain
¹¹⁰ Institute of Astrophysics, FORTH, Crete, Greece
¹¹¹ Barcelona Supercomputing Center (BSC), Plaça Eusebi Gell 1-3, 08034 Barcelona, Spain
¹¹² Center for Astrophysics and Cosmology, University of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia
¹¹³ F.R.S.-FNRS, Rue d’Egmont 5, 1000 Brussels, Belgium
¹¹⁴ Asteroid Engineering Laboratory, Luleå University of Technology, Box 848, 981 28 Kiruna, Sweden
¹¹⁵ IAC – Instituto de Astrofisica de Canarias, Via Láctea s/n, 38200 La Laguna S.C., Tenerife, Spain
¹¹⁶ Department of Astrophysics, University of La Laguna, Via Láctea s/n, 38200 La Laguna S.C., Tenerife, Spain
¹¹⁷ Las Cumbres Observatory, 6740 Cortona Drive Suite 102, Goleta, CA 93117, USA
¹¹⁸ Université Rennes, CNRS, IPR (Institut de Physique de Rennes), UMR 6251, 35000 Rennes, France
¹¹⁹ INAF – Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy
¹²⁰ Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, PR China
¹²¹ University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing 100049, PR China
¹²² São Paulo State University, Grupo de Dinâmica Orbital e Planetologia, CEP 12516-410, Guaratinguetá, SP, Brazil
¹²³ CIGUS CITIC, Department of Nautical Sciences and Marine Engineering, University of A Coruña, Paseo de Ronda 51, 15071 A Coruña, Spain
¹²⁴ Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UK
¹²⁵ IRAP, Université de Toulouse, CNRS, UPS, CNES, 9 Av. colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
¹²⁶ Serco Gestión de Negocios for European Space Agency (ESA), Camino bajo del Castillo, s/n, Urbanizacion Villafranca del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
¹²⁷ Astronomical Institute, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 180 00 Prague, Czech Republic
¹²⁸ Dribia Data Research S.L., Pg. de Gràcia, 55, 3r 4a 08007, Barcelona, Spain
¹²⁹ Pioneer Research Center for Climate and Earth Science, Institute for Basic Science, Daejeon 34126, Republic of Korea
¹³⁰ Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Kraków, Poland
¹³¹ Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Ave, New York, NY 10010, USA
¹³² INAF – Osservatorio Astronomico di Brera, Via E. Bianchi, 46, 23807 Merate, (LC), Italy
¹³³ National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
¹³⁴ Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 7610001, Israel
¹³⁵ Centre de Données Astronomique de Strasbourg, Strasbourg, France
¹³⁶ Astrophysics Group, Department of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, UK
¹³⁷ Departamento de Astrofísica, Centro de Astrobiología (CSIC-INTA), ESA-ESAC, Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
¹³⁸ naXys, Department of Mathematics, University of Namur, Rue de Bruxelles 61, 5000 Namur, Belgium
¹³⁹ INAF. Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, 34131 Trieste, Italy
¹⁴⁰ H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK
¹⁴¹ Instituto de Astronomia, Geofìsica e Ciências Atmosféricas, Universidade de São Paulo, Rua do Matão, 1226, Cidade Universitaria, 05508-900 São Paulo, SP, Brazil
¹⁴² Escuela de Arquitectura y Politécnica – Universidad Europea de Valencia, Valencia, Spain
¹⁴³ Escuela Superior de Ingeniería y Tecnología – Universidad Internacional de la Rioja, Rioja, Spain
¹⁴⁴ Institut fr Physik und Astronomie, Universitt Potsdam, Haus 28, Karl-Liebknecht-Str. 24/25, 14476 Golm, (Potsdam), Germany
¹⁴⁵ Applied Physics Department, Universidade de Vigo, 36310 Vigo, Spain
¹⁴⁶ Instituto de Física e Ciencias Aeroespaciais (IFCAE), Universidade de Vigo Campus de As Lagoas, 32004 Ourense, Spain
¹⁴⁷ Purple Mountain Observatory and Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210033, PR China
¹⁴⁸ Sorbonne Université, CNRS, UMR7095, Institut d’Astrophysique de Paris, 98bis bd. Arago, 75014 Paris, France
¹⁴⁹ Faculty of Mathematics and Physics, University of Ljubljana, Jadranska ulica 19, 1000 Ljubljana, Slovenia

Received: 27 February 2024
Accepted: 30 March 2024

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 32.70 ± 0.82 M_⊙ 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.