Publication Date
6-1-2024
Document Type
Article
Publication Title
Monthly Notices of the Royal Astronomical Society
Volume
531
Issue
1
DOI
10.1093/mnras/stae1274
First Page
1789
Last Page
1804
Abstract
We present spatially resolved Keck Cosmic Web Imager stellar spectroscopy of the Virgo cluster dwarf galaxies VCC 9 and VCC 1448. These galaxies have similar stellar masses and large half-light radii but very different globular cluster (GC) system richness (∼25 versus ∼99 GCs). Using the KCWI data, we spectroscopically confirm 10 GCs associated with VCC 1448 and one GC associated with VCC 9. We make two measurements of dynamical mass for VCC 1448 based on the stellar and GC velocities, respectively. VCC 1448’s mass measurements suggest that it resides in a halo in better agreement with the expectation of the stellar mass–halo mass relationship than the expectation from its large GC counts. For VCC 9, the dynamical mass we measure agrees with the expected halo mass from both relationships. We compare VCC 1448 and VCC 9 to the GC-rich galaxy Dragonfly 44 (∼74 GCs), which is similar in size but has ∼1 dex less stellar mass than either Virgo galaxy. In dynamical mass – GC number space, Dragonfly 44 and VCC 1448 exhibit richer GC systems given their dynamical mass than that of VCC 9 and other ‘normal’ galaxies. We also place the galaxies in kinematics–ellipticity space finding evidence of an anticorrelation between rotational support and the fraction of a galaxy’s stellar mass in its GC system, that is, VCC 9 is more rotationally supported than VCC 1448, which is more rotationally supported than Dragonfly 44. This trend may be expected if a galaxy’s GC content depends on its natal gas properties at formation.
Funding Number
CE170100013
Funding Sponsor
National Aeronautics and Space Administration
Keywords
galaxies: clusters: Virgo, galaxies: dwarf, galaxies: fundamental parameters, galaxies: individual: VCC 1448, galaxies: kinematics and dynamics
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Department
Physics and Astronomy
Recommended Citation
Jonah S. Gannon, Duncan A. Forbes, Aaron J. Romanowsky, Jean P. Brodie, Lydia Haacke, Anna Ferré-Mateu, Shany Danieli, Pieter van Dokkum, Maria Luisa Buzzo, Warrick J. Couch, and Zili Shen. "Analysis of galaxies at the extremes: a kinematic analysis of the Virgo cluster dwarfs VCC 9 and VCC 1448 using the Keck cosmic web imager" Monthly Notices of the Royal Astronomical Society (2024): 1789-1804. https://doi.org/10.1093/mnras/stae1274
