Publication Date
5-14-2020
Document Type
Article
Publication Title
Monthly Notices of the Royal Astronomical Society
Volume
495
Issue
3
DOI
10.1093/mnras/staa1282
First Page
2582
Last Page
2598
Abstract
Here, we present a kinematical analysis of the Virgo cluster ultradiffuse galaxy (UDG) VCC 1287 based on data taken with the Keck Cosmic Web Imager (KCWI). We confirm VCC 1287's association both with the Virgo cluster and its globular cluster (GC) system, measuring a recessional velocity of 1116 ± 2 km s-1. We measure a stellar velocity dispersion (19 ± 6 km s-1) and infer both a dynamical mass ($1.11^{+0.81}_{-0.81} \times 10^{9} \ \mathrm{M_{\odot }}$) and mass-To-light ratio (M/L) ($13^{+11}_{-11}$) within the half-light radius (4.4 kpc). This places VCC 1287 slightly above the well-established relation for normal galaxies, with a higher M/L for its dynamical mass than normal galaxies. We use our dynamical mass, and an estimate of GC system richness, to place VCC 1287 on the GC number-dynamical mass relation, finding good agreement with a sample of normal galaxies. Based on a total halo mass derived from GC counts, we then infer that VCC 1287 likely resides in a cored or low-concentration dark matter halo. Based on the comparison of our measurements to predictions from simulations, we find that strong stellar feedback and/or tidal effects are plausibly the dominant mechanisms in the formation of VCC 1287. Finally, we compare our measurement of the dynamical mass with those for other UDGs. These dynamical mass estimates suggest relatively massive haloes and a failed galaxy origin for at least some UDGs.
Funding Number
1518294
Funding Sponsor
National Science Foundation
Keywords
galaxies: formation, galaxies: haloes, galaxies: kinematics and dynamics, techniques: spectroscopic
Department
Physics and Astronomy
Recommended Citation
Jonah S. Gannon, Duncan A. Forbes, Aaron J. Romanowsky, Anna Ferré-Mateu, Warrick J. Couch, and Jean P. Brodie. "On the stellar kinematics and mass of the Virgo ultradiffuse galaxy VCC 1287" Monthly Notices of the Royal Astronomical Society (2020): 2582-2598. https://doi.org/10.1093/mnras/staa1282
Comments
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.