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THE M31 VELOCITY VECTOR. II. RADIAL ORBIT TOWARD THE MILKY WAY AND IMPLIED LOCAL GROUP MASS
Open accessAbstract
We determine the velocity vector of M31 with respect to the Milky Way and use this to constrain the mass of the Local Group, based on Hubble Space Telescope proper-motion measurements of three fields presented in Paper I. We construct N -body models for M31 to correct the measurements for the contributions from stellar motions internal to M31. This yields an unbiased estimate for the M31 center-of-mass motion. We also estimate the center-of-mass motion independently, using the kinematics of satellite galaxies of M31 and the Local Group, following previous work but with an expanded satellite sample. All estimates are mutually consistent, and imply a weighted average M31 heliocentric transverse velocity of ( v W , v N ) = (− 125.2 ± 30.8, −73.8 ± 28.4) km s −1 . We correct for the reflex motion of the Sun using the most recent insights into the solar motion within the Milky Way, which imply a larger azimuthal velocity than previously believed. This implies a radial velocity of M31 with respect to the Milky Way of V rad, M31 = −109.3 ± 4.4 km s −1 , and a tangential velocity of V tan, M31 = 17.0 km s −1 , with a 1σ confidence region of V tan, M31 ⩽ 34.3 km s −1 . Hence, the velocity vector of M31 is statistically consistent with a radial (head-on collision) orbit toward the Milky Way. We revise prior estimates for the Local Group timing mass, including corrections for cosmic bias and scatter, and obtain M LG ≡ M MW, vir + M M31, vir = (4.93 ± 1.63) × 10 12 M ☉ . Summing known estimates for the individual masses of M31 and the Milky Way obtained from other dynamical methods yields smaller uncertainties. Bayesian combination of the different estimates demonstrates that the timing argument has too much (cosmic) scatter to help much in reducing uncertainties on the Local Group mass, but its inclusion does tend to increase other estimates by ∼10%. We derive a final estimate for the Local Group mass from literature and new considerations of M LG = (3.17 ± 0.57) × 10 12 M ☉ . The velocity and mass results at 95% confidence imply that M33 is bound to M31, consistent with expectation from observed tidal deformations.
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“Such a tilt can be a result of a westward CGM wind due to the relative motion ( v cgm -wind ∼ 50 km s -1 ) of the MW in the local galaxy group medium (van der Marel et al. 2012).”
From The Fermi/eROSITA bubbles: a look into the nuclear outflow from the Milky Way (2024) · cites this paper as van der Marel et al. 2012
Citations
Cites
A Universal Density Profile from Hierarchical Clustering
Navarro, J. F., Frenk, C. S., & White, S. D. M. (1997) · The Astrophysical Journal · doi:10.1086/304888 · Cited by 9,917
A Universal Density Profile from Hierarchical ClusteringPreprint
Navarro, J. F., Frenk, C. S., & White, S. D. M. (1996) · Cited by 6,275
An analytical model for spherical galaxies and bulges
Hernquist, L. (1990) · The Astrophysical Journal · doi:10.1086/168845 · Cited by 3,166
Astrophysics Source Code LibraryPreprint
Allen, A., DuPrie, K., Berriman, G. B., Hanisch, R. J., Mink, J. D., & Teuben, P. J. (2012) · arXiv (Cornell University) · doi:10.48550/arxiv.1212.1916 · Cited by 2,722
Modelling feedback from stars and black holes in galaxy mergers
Springel, V., Matteo, T. D., & Hernquist, L. (2005) · Monthly Notices of the Royal Astronomical Society · doi:10.1111/j.1365-2966.2005.09238.x · Cited by 2,233
Local kinematics and the local standard of rest
Schönrich, R. A., Binney, J. J., & Dehnen, W. (2010) · Monthly Notices of the Royal Astronomical Society · doi:10.1111/j.1365-2966.2010.16253.x · Cited by 1,934
MONITORING STELLAR ORBITS AROUND THE MASSIVE BLACK HOLE IN THE GALACTIC CENTER
Gillessen, S., Eisenhauer, F., Trippe, S., Alexander, T., Genzel, R., Martins, F., & Ott, T. (2009) · The Astrophysical Journal · doi:10.1088/0004-637x/692/2/1075 · Cited by 1,779
Ghez, A. M., Salim, S., Weinberg, N. N., Lu, J. R., Do, T., Dunn, J. K., Matthews, K., Morris, M. R., Yelda, S., Becklin, E. E., et al. (2008) · The Astrophysical Journal · doi:10.1086/592738 · Cited by 1,577
Jarosik, N., Bennett, C. L., Dunkley, J., Gold, B., Greason, M. R., Halpern, M., Hill, R. S., Hinshaw, G., Kogut, A., Komatsu, E., et al. (2011) · The Astrophysical Journal Supplement Series · doi:10.1088/0067-0049/192/2/14 · Cited by 1,115
Local stellar kinematics from Hipparcos data
Dehnen, W., & Binney, J. J. (1998) · Monthly Notices of the Royal Astronomical Society · doi:10.1046/j.1365-8711.1998.01600.x · Cited by 1,049
Research works printed but not linked: 4
- Dorman, 2012, ApJ
- Fardal, 2012, MNRAS
- Lynden-Bell, 1981, Observatory, 101, 111
- Tollerud, 2012, ApJ
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Self-citation
Metadata
- Authors
- van der Marel, R. P., Fardal, M., Besla, G., Beaton, R. L., Sohn, S. T., Anderson, J., Brown, T., & Guhathakurta, P.
- Affiliations
- Space Telescope Science Institute (US)
- University of Massachusetts Amherst (US)
- Columbia University (US)
- University of Virginia (US)
- University of California, Santa Cruz (US)
- ORCID
- Venue
- The Astrophysical Journal
- Publisher
- American Astronomical Society
- Published
- 2012-06-08
- Volume
- 753
- Issue
- 1
- Pages
- 8
- ISSN
- 0004-637X (ISSN-L)
- 1538-4357
- OpenAlex
- W2110691121
- Cited by
- 259
- References
- 108
- Citations by year
- 2026: 10 · 2025: 20 · 2024: 22 · 2023: 18 · 2022: 17 · 2021: 15 · 2020: 19 · 2019: 13 · 2018: 19 · 2017: 15 · 2016: 19 · 2015: 19 · 2014: 30 · 2013: 17 · 2012: 6
- FWCI
- 12.61
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- The Astrophysical Journal (publishedVersion)
- arXiv (Cornell University) (publishedVersion)
- arXiv (Cornell University)
- Funders
- National Science Foundation (1009652, NAS 5-26555)
- National Aeronautics and Space Administration (NAS 526555, 526555)
- Space Telescope Science Institute (NAS5- 26555, 5-26555, 26555)
- Topics
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Galaxies: Formation, Evolution, Phenomena
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Stellar, planetary, and galactic studies
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Cosmology and Gravitation Theories
- Keywords
- M31, Local Group mass, radial velocity, proper motions, Milky Way, head-on collisions, N-body simulations, center-of-mass motion, satellite galaxies, timing argument, M33, M32, M101, M104
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