Improving constraints on the extended mass distribution in the Galactic center with stellar orbits

Studying the orbital motion of stars around Sagittarius A* in the Galactic center provides a unique opportunity to probe the gravitational potential near the supermassive black hole at the heart of our Galaxy. Interferometric data obtained with the GRAVITY instrument at the Very Large Telescope Interferometer (VLTI) since 2016 has allowed us to achieve unprecedented precision in tracking the orbits of these stars. GRAVITY data have been key to detecting the in-plane, prograde Schwarzschild precession of the orbit of the star S2 that is predicted by general relativity. By combining astrometric and spectroscopic data from multiple stars, including S2, S29, S38, and S55 – for which we have data around their time of pericenter passage with GRAVITY – we can now strengthen the significance of this detection to an approximately 10 σ confidence level. The prograde precession of S2’s orbit provides valuable insights into the potential presence of an extended mass distribution surrounding Sagittarius A*, which could consist of a dynamically relaxed stellar cusp comprising old stars and stellar remnants, along with a possible dark matter spike. Our analysis, based on two plausible density profiles – a power-law and a Plummer profile – constrains the enclosed mass within the orbit of S2 to be consistent with zero, establishing an upper limit of approximately 1200 M ⊙ with a 1 σ confidence level. This significantly improves our constraints on the mass distribution in the Galactic center. Our upper limit is very close to the expected value from numerical simulations for a stellar cusp in the Galactic center, leaving little room for a significant enhancement of dark matter density near Sagittarius A*.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2024-11-28
DOI
https://doi.org/10.1051/0004-6361/202452274
Citations
28
Primary Topic
Astrophysical Phenomena and Observations
Type
article
Field-Weighted Citation Impact
9.28

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article

Improving constraints on the extended mass distribution in the Galactic center with stellar orbits

F. Haussmann, C. Straubmeier, M. Hartl, S. Lacour et al.
28 citations
Astronomy and Astrophysics
Astrophysical Phenomena and Observations
9.28
article

Improving constraints on the extended mass distribution in the Galactic center with stellar orbits

F. Haussmann, C. Straubmeier, M. Hartl, S. Lacour, G. Finger, K. Perraut, R. Capuzzo‐Dolcetta, E. Wieprecht, D. C. Ribeiro, A. Drescher, S. Hippler, Pierre Léna, Jean-Philippe Berger, Fupeng Zhang, J. Shangguan, G. Bourdarot, A. Kaufer, R. Davies, P. T. de Zeeuw, M. Horrobin, T. Ott, R. Genzel, T. Paumard, Nikhil More, Pau Amaro‐Seoane, J. Stadler, G. Heißel, A. Eckart, Vítor Cardoso, V. Lapeyrère, G. Perrin, D. Lutz, L. Jocou, H. Feuchtgruber, Silvia Scheithauer, A. Amorim, Thomas Shimizu, S. Gillessen, J. G. Beck, P. Kervella, J.-B. Le Bouquin, X. Haubois, S. Rabien, Thomas Henning, P. García, A. Foschi, S. D. von Fellenberg, R. Abuter, N. Aimar, N. M. Förster Schreiber, K. Abd El Dayem, E. Gendron, Frédéric E. Vincent, Frank Eisenhauer, F. Widmann, J. Woillez, L. Jochum, O. Straub, Y. Clénet, W. Brandner, O. Pfuhl, L. J. Tacconi, F. Mang, E. Sturm, I. Urso, H. Bonnet, M. S. Bordoni, F. Gao
article en
28 citations

Abstract

Studying the orbital motion of stars around Sagittarius A* in the Galactic center provides a unique opportunity to probe the gravitational potential near the supermassive black hole at the heart of our Galaxy. Interferometric data obtained with the GRAVITY instrument at the Very Large Telescope Interferometer (VLTI) since 2016 has allowed us to achieve unprecedented precision in tracking the orbits of these stars. GRAVITY data have been key to detecting the in-plane, prograde Schwarzschild precession of the orbit of the star S2 that is predicted by general relativity. By combining astrometric and spectroscopic data from multiple stars, including S2, S29, S38, and S55 – for which we have data around their time of pericenter passage with GRAVITY – we can now strengthen the significance of this detection to an approximately 10 σ confidence level. The prograde precession of S2’s orbit provides valuable insights into the potential presence of an extended mass distribution surrounding Sagittarius A*, which could consist of a dynamically relaxed stellar cusp comprising old stars and stellar remnants, along with a possible dark matter spike. Our analysis, based on two plausible density profiles – a power-law and a Plummer profile – constrains the enclosed mass within the orbit of S2 to be consistent with zero, establishing an upper limit of approximately 1200 M ⊙ with a 1 σ confidence level. This significantly improves our constraints on the mass distribution in the Galactic center. Our upper limit is very close to the expected value from numerical simulations for a stellar cusp in the Galactic center, leaving little room for a significant enhancement of dark matter density near Sagittarius A*.

Astronomy and AstrophysicsVol. 692
Centre National de la Recherche Scientifique (FR), European Southern Observatory (DE), University of Lisbon (PT), Délégation Paris 7 (FR), University of Cologne (DE), Universidade do Porto (PT), Université Paris Cité (FR), Observatoire de Paris (FR), Guangzhou University (CN), Sorbonne Université (FR), Institute of Astrophysics and Space Sciences (PT), Max Planck Institute for Extraterrestrial Physics (DE), Key Laboratory of Guangdong Province (CN), Excellence Cluster Origins (DE), Max Planck Institute for Astrophysics (DE), Kavli Institute for Theoretical Sciences (CN), Department of Education of Guangdong Province (CN), Centro de Astrofísica da Universidade do Porto (PT), Max Planck Institute for Astronomy (DE), Institut de Planétologie et d'Astrophysique de Grenoble (FR), Laboratoire d’études spatiales et d’instrumentation en astrophysique (FR), European Southern Observatory (CL), Max Planck Institute for Radio Astronomy (DE), Universitat Politècnica de València (ES), Technical University of Munich (DE), Université Grenoble Alpes (FR), University of California, Berkeley (US)
European Commission, Deutsche Forschungsgemeinschaft, Bundesministerium für Bildung und Forschung, Max-Planck-Gesellschaft, European Southern Observatory, Centre National de la Recherche Scientifique, Observatoire de Paris, Université de Recherche Paris Sciences et Lettres, Fundação para a Ciência e a Tecnologia
Openalex Percentile: Top 2%
Astrophysical Phenomena and Observations
9.28
DOIOpen Access PDFOpenAlex
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