CaltechAUTHORS
Published October 20, 2022 | Version public
Journal Article Metadata-only

The Hubble Space Telescope Survey of M31 Satellite Galaxies. I. RR Lyrae-based Distances and Refined 3D Geometric Structure

Creators

  • 1. ROR icon University of California, Berkeley
  • 2. ROR icon University of Minnesota
  • 3. ROR icon University of Arizona
  • 4. ROR icon University of Virginia
  • 5. ROR icon University of California, Davis
  • 6. ROR icon Space Telescope Science Institute
  • 7. ROR icon The University of Texas at Austin
  • 8. ROR icon University of California, Irvine
  • 9. ROR icon University of Tasmania
  • 10. ROR icon University of Surrey
  • 11. ROR icon Durham University
  • 12. ROR icon Dartmouth College
  • 13. ROR icon University of Edinburgh
  • 14. ROR icon Yale University
  • 15. ROR icon Johns Hopkins University
  • 16. ROR icon University of California, Santa Cruz
  • 17. ROR icon Observatory of Strasbourg
  • 18. ROR icon University of Cambridge
  • 19. ROR icon Kyung Hee University
  • 20. ROR icon California Institute of Technology
  • 21. ROR icon University of Notre Dame
  • 22. ROR icon University of Sydney
  • 23. ROR icon Australian National University
  • 24. ROR icon Max Planck Institute for Astronomy
  • 25. ROR icon Herzberg Institute of Astrophysics
  • 26. ROR icon University of Victoria
  • 27. ROR icon New York State Office for People With Developmental Disabilities
  • 28. ROR icon University of California, Los Angeles
  • 29. ROR icon Carnegie Observatories

Abstract

We measure homogeneous distances to M31 and 38 associated stellar systems (−16.8 ≤ M_V ≤ −6.0), using time-series observations of RR Lyrae stars taken as part of the Hubble Space Telescope Treasury Survey of M31 Satellites. From >700 orbits of new/archival Advanced Camera for Surveys imaging, we identify >4700 RR Lyrae stars and determine their periods and mean magnitudes to a typical precision of 0.01 day and 0.04 mag. Based on period–Wesenheit–metallicity relationships consistent with the Gaia eDR3 distance scale, we uniformly measure heliocentric and M31-centric distances to a typical precision of ∼20 kpc (3%) and ∼10 kpc (8%), respectively. We revise the 3D structure of the M31 galactic ecosystem and: (i) confirm a highly anisotropic spatial distribution such that ∼80% of M31's satellites reside on the near side of M31; this feature is not easily explained by observational effects; (ii) affirm the thin (rms 7–23 kpc) planar "arc" of satellites that comprises roughly half (15) of the galaxies within 300 kpc from M31; (iii) reassess the physical proximity of notable associations such as the NGC 147/185 pair and M33/AND xxii; and (iv) illustrate challenges in tip-of-the-red-giant branch distances for galaxies with M_V > − 9.5, which can be biased by up to 35%. We emphasize the importance of RR Lyrae for accurate distances to faint galaxies that should be discovered by upcoming facilities (e.g., Rubin Observatory). We provide updated luminosities and sizes for our sample. Our distances will serve as the basis for future investigation of the star formation and orbital histories of the entire known M31 satellite system.

Additional Information

A.S. thanks Y. Zheng for useful discussions at various stages of this work. Support for this work was provided by NASA through grants GO-13768, GO-15746, GO-15902, AR-16159, and GO-16273 from the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555. M.C.C. acknowledges support though NSF grant AST-1815475. M.B.K. acknowledges support from NSF CAREER award AST-1752913, NSF grants AST-1910346 and AST-2108962, NASA grant NNX17AG29G, and HST-AR-15006, HST-AR-15809, HST-GO-15658, HST-GO-15901, HST-GO-15902, HST-AR-16159, and HST-GO-16226 from STScI. A.S. wishes to thank M. Marconi and R. Molinaro for providing the PWZ scaling relations used in this paper. This research has made use of NASA's Astrophysics Data System Bibliographic Services. All of the HST data used in this paper can be found in MAST:10.17909/jb41-ex86.

Additional details

Identifiers

Eprint ID
117668
Resolver ID
CaltechAUTHORS:20221031-575177800.33

Funding

NASA
HST-GO-13768
NASA
HST-GO-15746
NASA
HST-GO-15902
NASA
HST-AR-16159
NASA
HST-GO-16273
NASA
NAS5-26555
NSF
AST-1815475
NSF
AST-1752913
NSF
AST-1910346
NSF
AST-2108962
NASA
NNX17AG29G
NASA
HST-AR-15006
NASA
HST-AR-15809
NASA
HST-GO-15658
NASA
HST-GO-15901
NASA
HST-GO-15902
NASA
HST-AR-16159
NASA
HST-GO-16226

Dates

Created
2022-11-09
Created from EPrint's datestamp field
Updated
2022-11-11
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Astronomy Department