The need for speed : escape velocity and dynamical mass measurements of the Andromeda galaxy
| Autor: | Simon P. Driver, Geraint F. Lewis, Aaron S. G. Robotham, Prajwal R. Kafle, Sanjib Sharma |
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| Přispěvatelé: | University of St Andrews. School of Physics and Astronomy |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
statistical [Methods]
Cosmology and Nongalactic Astrophysics (astro-ph.CO) Andromeda Galaxy Stellar mass Astrophysics::High Energy Astrophysical Phenomena individual: planetary nebulae [Stars] FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences individual: M31 [Galaxies] 0103 physical sciences Satellite galaxy QB Astronomy 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics QC QB Physics 010308 nuclear & particles physics kinematics and dynamics [Galaxies] Local Group Astronomy and Astrophysics Virial mass Escape velocity 3rd-DAS Astrophysics - Astrophysics of Galaxies Galaxy Dark matter halo QC Physics Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Astrophysics - Cosmology and Nongalactic Astrophysics |
| Popis: | Our nearest large cosmological neighbour, the Andromeda galaxy (M31), is a dynamical system, and an accurate measurement of its total mass is central to our understanding of its assembly history, the life-cycles of its satellite galaxies, and its role in shaping the Local Group environment. Here, we apply a novel approach to determine the dynamical mass of M31 using high velocity Planetary Nebulae (PNe), establishing a hierarchical Bayesian model united with a scheme to capture potential outliers and marginalize over tracers unknown distances. With this, we derive the escape velocity run of M31 as a function of galacto-centric distance, with both parametric and non-parametric approaches. We determine the escape velocity of M31 to be $470\pm{40}$ km s$^{-1}$ at a galacto-centric distance of 15 kpc, and also, derive the total potential of M31, estimating the virial mass and radius of the galaxy to be $0.8\pm{0.1}\times10^{12}\,M_\odot$ and $240\pm{10}$ kpc, respectively. Our M31 mass is on the low-side of the measured range, this supports the lower expected mass of the M31-Milky Way system from the timing and momentum arguments, satisfying the HI constraint on circular velocity between $10\lesssim R/\textrm{kpc} Comment: 14 pages, 7 figures, 1 table. Accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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