S18A0021abst
S18A0021
We propose to carry out a spectroscopic follow-up observation for a ultra-faint dwarf galaxy in the Milky Way, Virgo I, which has recently been discovered by our group from the Hyper Suprime-Cam (HSC) survey data. This galaxy is one of the faintest dwarf satellites ever discovered, with the V-band absolute magnitude of only MV ≃ −0.33 mag, and is located at the heliocentric distance of 91 kpc, which is just at the limit where Subaru/HSC can really reach for identifying this very low-luminosity galaxy. Medium resolution spectroscopy of seven candidate bright member stars in Virgo I, including red giant branch and asymptotic giant branch stars, as well as candidate field halo stars in the same direction, will allow us to assess the membership in Virgo I through the analysis of their radial velocities. Based on the obtained radial velocity dispersion of the genuine member stars, we will estimate the dynamical mass in this system. Combined with metallicity measurements for candidate member stars, we will constrain the basic chemo-dynamical properties of this newly discovered ultra-faint dwarf galaxy and probe the mass-metallicity relation at the lowest mass end.
This document was translated from LATEX by HEVEA.