1508.07369
Sub-kiloparsec imaging of cool molecular gas in two strongly lensed dusty, star-forming galaxies
Spilker, et al
Two objects at z=2.78 and 5.66, with effective source-plane resolution of less than 1kpc. The cold molecular gas as traced by low-J CO always has a larger half-light radius than the 870um dust continuum emission. ...
1508.07373
The most massive ultra-compact dwarf galaxy in the Virgo Cluster
Liu, et al
Report on the properties of the most massive UCD in the nearby Virgo Cluster of galaxies using imaging from the NGVS and spectroscopy from Keck/DEIMOS. This object (M59-UCD3) appears to be associated with the massive Virgo galaxy M59 (NGC 4621), has an integrated velocity dispersion of 78 km/s, a dynamical mass of 3.7e8 Mxun, and an effective radius (Re) of 25 pc. With an effective surface mass density of 9.4e10 Msun/kpc^2, it is the densest galaxy in the local Universe discovered to date, surpassing the density of the luminous Virgo UCD, M60-UCD1. M59-UCD3 has a total luminosity of M_g'=-14.2 mag, and a spectral energy distribution consistent with an old (14 Gyr) stellar population with [Fe/H]=0.0 and [alpha/Fe]=+0.2. Also examine deep imaging around M59 and find a broad low surface brightness stream pointing towards M59-UCD3, which may represent a tidal remnant of the UCD progenitor. This UCD, along with similar objects like M60-UCD1 and M59cO, likely represents an extreme population of tidally stripped galaxies more akin to larger and more massive compact early-type galaxies than to nuclear star clusters in present-day dwarf galaxies.
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