Gemini Spectroscopy of Ultra-Compact Dwarfs in the Fossil Group NGC 1132
Abstract
A spectroscopic follow up of Ultra-Compact Dwarf (UCD) candidates in the fossil group NGC 1132 is undertaken with the Gemini Multi Object Spectrograph (GMOS). These new Gemini spectra prove the presence of six UCDs in the fossil group NGC 1132 at a distance of D~100 Mpc and a recessional velocity of vr = 6935 +/- 11 km/s. The brightest and largest member of the UCD population is an M32 analog with a size of 77.1 pc and a magnitude of MV=-14.8 mag with the characteristics in between those of the brightest UCDs and compact elliptical galaxies. The ensemble of UCDs have an average radial velocity of <vr> = 6966 +/- 208 km/s and a velocity dispersion of sigmav = 169 +/-18 km/s similar to the one of poor galaxy groups. This work shows that UCDs can be used as test particles to determine the dynamical properties of galaxy groups. The presence of UCDs in the fossil group environment is confirmed and thus the fact that UCDs can form across diverse evolutionary conditions.
Turn this paper into a lesson
ArcXiv compiles a structured reading guide from this paper's metadata: plain-English importance, contributions, prerequisite concepts, which sections to read first, flashcards, and a quiz. Grounded in the abstract, never invented.