Kinematics and metallicity of the dwarf spheroidal galaxy Andromeda XVIII
arXiv:2404.11804 · doi:10.3847/1538-4357/ad55f0
Abstract
Andromeda XVIII is an isolated dwarf galaxy 579 kpc away from the nearest large galaxy, M31. It is a candidate "backsplash galaxy" that might have been affected by a close passage to M31. We present new Keck/DEIMOS spectroscopy of Andromeda XVIII to assess the likelihood that it is a backsplash galaxy. We estimated the velocities, metallicities ([Fe/H]), and -enhancements ([/Fe]) for 56 probable members. Based on the abundances of 38 stars with low errors (), parameters for the simplest chemical evolution models were estimated using the maximum likelihood coupled with a Markov Chain Monte Carlo (MCMC) method. The metallicity distribution is inconsistent with these models, due to a sharp metal-rich cutoff. We estimated Andromeda XVIII's mean heliocentric velocity, rotation velocity, position angle of the rotation axis, and velocity dispersion using the maximum likelihood coupled with an MCMC. There is no evidence for bulk rotation, though subpopulations might be rotating. The mean heliocentric velocity is -337.2 km s, such that the line-of-sight velocity relative to M31 is lower than the escape velocity from M31. Together, the metallicity distribution and the mean velocity are consistent with a sudden interruption of star formation. For possible causes of this quenching, we considered gas loss due to ram pressure stripping during a close passage by M31 or due to a past major merger. However, we cannot rule out internal feedback (i.e., a terminal wind).
arXiv comment24 pages, 13 figures, 4 tables
References in corpus (65)
- SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
- Astropy: A Community Python Package for Astronomy
- emcee: The MCMC Hammer
- The NumPy array: a structure for efficient numerical computation
- The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
- The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
- The USNO-B Catalog
- The observed properties of dwarf galaxies in and around the Local Group
- Theoretical isochrones in several photometric systems I. Johnson-Cousins-Glass, HST/WFPC2, HST/NICMOS, Washington, and ESO Imaging Survey filter sets
- The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
- The Universal Stellar Mass-Stellar Metallicity Relation for Dwarf Galaxies
- The DEEP2 Galaxy Redshift Survey: Design, Observations, Data Reduction, and Redshifts
- Accurate masses for dispersion-supported galaxies
- A Method for Measuring (Slopes of) the Mass Profiles of Dwarf Spheroidal Galaxies
- The ACS Nearby Galaxy Survey Treasury VIII. The Global Star Formation Histories of 60 Dwarf Galaxies in the Local Volume
- Multi-Element Abundance Measurements from Medium-Resolution Spectra. III. Metallicity Distributions of Milky Way Dwarf Satellite Galaxies
- The large-scale structure of the halo of the Andromeda Galaxy Part I: global stellar density, morphology and metallicity properties
- The M31 Velocity Vector. II. Radial Orbit Towards the Milky Way and Implied Local Group Mass
- The NIR Ca II triplet at low metallicity - Searching for extremely low-metallicity stars in classical dwarf galaxies
- Analysis and calibration of CaII triplet spectroscopy of Red Giant Branch stars from VLT/FLAMES observations
- Multi-Element Abundance Measurements from Medium-Resolution Spectra. II. Catalog of Stars in Milky Way Dwarf Satellite Galaxies
- A kinematic study of the Andromeda dwarf spheroidal system
- The large-scale structure of the halo of the Andromeda galaxy II. Hierarchical structure in the Pan-Andromeda Archaeological Survey
- A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude (Part II); Distances to the Satellites of M31
- Milky Way Satellite Census. I. The Observational Selection Function for Milky Way Satellites in DES Y3 and Pan-STARRS DR1
- The SPLASH Survey: Spectroscopy of 15 M31 Dwarf Spheroidal Satellite Galaxies
- Multi-Element Abundance Measurements from Medium-Resolution Spectra. I. The Sculptor Dwarf Spheroidal Galaxy
- A trio of new Local Group galaxies with extreme properties
- Gaia Proper Motions and Orbits of the Ultra-Faint Milky Way Satellites
- Still Missing Dark Matter: KCWI High-Resolution Stellar Kinematics of NGC1052-DF2
- Exploring Halo Substructure with Giant Stars: I. Survey Description and Calibration of the Photometric Search Technique
- The Dearth of Neutral Hydrogen in Galactic Dwarf Spheroidal Galaxies
- Metallicity and Alpha-Element Abundance Measurement in Red Giant Stars from Medium Resolution Spectra
- Exploring Halo Substructure with Giant Stars X. Extended Dark Matter or Tidal Disruption?: The Case for the Leo I Dwarf Spheroidal Galaxy
- Spectroscopic Confirmation of the Dwarf Galaxies Hydra II and Pisces II and the Globular Cluster Laevens 1
- Identifying Local Group Field Galaxies which have interacted with the Milky Way
- The M31 Velocity Vector. III. Future Milky Way-M31-M33 Orbital Evolution, Merging, and Fate of the Sun
- Resonant stripping as the origin of dwarf spheroidal galaxies
- Global Properties of M31's Stellar Halo from the SPLASH Survey. I. Surface Brightness Profile
- The triggering of starbursts in low-mass galaxies
- A New Method for Isolating M31 Red Giant Stars: The Discovery of Stars out to a Radial Distance of 165 Kiloparsecs
- Discovery of Andromeda XIV: A Dwarf Spheroidal Dynamical Rogue in the Local Group?
- The Comparative Chemical Evolution of an Isolated Dwarf Galaxy: A VLT and Keck Spectroscopic Survey of WLM
- Mergers and the outside-in formation of dwarf spheroidals
- Carbon in Red Giants in Globular Clusters and Dwarf Spheroidal Galaxies
- An Infrared Census of DUST in Nearby Galaxies with Spitzer (DUSTiNGS), I. Overview
- Quiescent Ultra-diffuse galaxies in the field originating from backsplash orbits
- Evidence for Ultra-Diffuse Galaxy `Formation' Through Galaxy Interactions
- Grids of ATLAS9 Model Atmospheres and MOOG Synthetic Spectra
- Comparing the Quenching Times of Faint M31 and Milky Way Satellite Galaxies
- The stellar metallicity gradients of Local Group dwarf galaxies
- Renegade Subhaloes in the Local Group
- Pericentric passage-driven star formation in satellite galaxies and their hosts: CLUES from Local Group simulations
- An Infrared Census Of Dust In Nearby Galaxies With Spitzer (DUSTiNGS): V. The Period-luminosity Relation For Dusty Metal-Poor AGB Stars
- JWST-TST Proper Motions: I. High-Precision NIRISS Calibration and Large Magellanic Cloud Kinematics
- The distinct stellar metallicity populations of simulated Local Group dwarfs
- Long-term orbital evolution of Galactic satellites and the effects on their star formation histories
- Elemental Abundances in M31: Alpha and Iron Element Abundances from Low-Resolution Resolved Stellar Spectroscopy in the Stellar Halo
- On the early evolution of Local Group dwarf galaxy types: star formation and supernova feedback
- Star formation history of And XVIII: a dwarf spheroidal galaxy in isolation
- Elemental abundances in M31: [Fe/H] and [α/Fe] in M31 Dwarf Galaxies Using Coadded Spectra
- Solo dwarfs IV: Comparing and contrasting satellite and isolated dwarf galaxies in the Local Group
- A new kinematic model of the Galaxy: analysis of the stellar velocity field from Gaia Data Release 3
- Origin of stellar prolate rotation in a cosmologically simulated faint dwarf galaxy
- The rotational kinetic Sunyaev-Zeldovich contribution to the temperature asymmetry toward the M31 halo