CaltechAUTHORS
Published May 10, 2023 | Version Published
Journal Article Open

Evidence of a Decreased Binary Fraction for Massive Stars within 20 milliparsecs of the Supermassive Black Hole at the Galactic Center

Creators

  • 1. ROR icon University of California, Los Angeles
  • 2. ROR icon University of California, Berkeley
  • 3. ROR icon California Institute of Technology

Abstract

We present the results of the first systematic search for spectroscopic binaries within the central 2 × 3 arcsec² around the supermassive black hole at the center of the Milky Way galaxy. This survey is based primarily on over a decade of adaptive optics-fed integral-field spectroscopy (R ∼ 4000), obtained as part of the Galactic Center Orbits Initiative at Keck Observatory, and it has a limiting K'-band magnitude of 15.8, which is at least 4 mag deeper than previous spectroscopic searches for binaries at larger radii within the central nuclear star cluster. From this primary data set, over 600 new radial velocities are extracted and reported, increasing by a factor of 3 the number of such measurements. We find no significant periodic signals in our sample of 28 stars, of which 16 are massive, young (main-sequence B) stars and 12 are low-mass, old (M and K giant) stars. Using Monte Carlo simulations, we derive upper limits on the intrinsic binary star fraction for the young star population at 47% (at 95% confidence) located ∼20 mpc from the black hole. The young star binary fraction is significantly lower than that observed in the field (70%). This result is consistent with a scenario in which the central supermassive black hole drives nearby stellar binaries to merge or be disrupted, and it may have important implications for the production of gravitational waves and hypervelocity stars.

Additional Information

© 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. We are grateful for the helpful and constructive comments from the referee. We thank M. R. Morris for his comments and long-term efforts on the Galactic Center Orbits Initiative. The primary data for this work were collected with the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. We wish to recognize that the summit of Maunakea has always held a very significant cultural role for the indigenous Hawaiian community. We are most fortunate to have the opportunity to observe from this mountain. We also thank the staff of the Keck Observatory, especially Jim Lyke, Randy Campbell, Gary Puniwai, Heather Hershey, Hien Tran, Scott Dahm, Jason McIlroy, Joel Hicock, and Terry Stickel, for all their help in obtaining the new observations. Finally, we are grateful for the financial support for this work provided by NSF AST grants 1412615 and 1909554, the Gordon & Betty Moore Foundation, the Levine–Leichtman Family Foundation, Ken and Eileen Kaplan Student Support Fund, the Galactic Center Board of Advisors, and the Janet Marott Student Travel Awards. S.N. acknowledges the partial support from NASA ATP 80NSSC20K0505 and from NSF-AST 2206428 grants and thanks Howard and Astrid Preston for their generous support. Facilities: W. M. Keck Observatory - , Gemini North Observatory. - Software: Numpy (van der Walt et al. 2011; Harris et al. 2020), Astropy (Astropy Collaboration et al. 2013, 2018), Starkit (Kerzendorf & Do 2015), gatspy (VanderPlas & Ivezić 2015; VanderPlas 2018), IRAF (Tody 1986, 1993), Multinest (Feroz & Hobson 2008; Feroz et al. 2009, 2019), SPISEA (Hosek et al. 2020a; Hosek et al. 2020b), Scipy (Virtanen et al. 2020), OSIRIS Data Reduction Pipeline (Lyke et al. 2017; Lockhart et al. 2019).

Attached Files

Published - Chu_2023_ApJ_948_94.pdf

Files

Chu_2023_ApJ_948_94.pdf

Files (6.0 MB)

Name Size Download all
md5:8e3d21dde5d5e223a5494bbee5b0759e
6.0 MB Preview Download

Additional details

Identifiers

Eprint ID
121651
Resolver ID
CaltechAUTHORS:20230531-151922700.3

Funding

NSF
AST-1412615
NSF
AST-1909554
Gordon and Betty Moore Foundation
Levine-Leichtman Family Foundation
Ken and Eileen Kaplan Student Support Fund
Galactic Center Board of Advisors
Janet Marott Student Travel Awards
NASA
80NSSC20K0505
NSF
AST-2206428

Dates

Created
2023-07-11
Created from EPrint's datestamp field
Updated
2023-07-11
Created from EPrint's last_modified field