The Ubiquitous Radio Continuum Emission from the Most Massive Early-Type Galaxies
The Ubiquity and Dual Nature of Ultra Compact Dwarfs
The UDF05 Follow-up of the Hubble Ultra Deep Field. III. The Luminosity Function at z~6
The UFFO (Ultra-Fast Flash Observatory) Pathfinder
The ugrizYJHK luminosity distributions and densities from the combined MGC, SDSS and UKIDSS LAS datasets
The Ultraluminous State
The ultraviolet flare at the center of the elliptical galaxy NGC 4278
The Ultraviolet Spectrum of the Gravitationally Lensed Galaxy `The Cosmic Horseshoe': A Close-up of a Star-forming Galaxy at z = 2
The Ultraviolet-to-Mid-Infrared Spectral Energy Distribution of Weak Emission Line Quasars
The Ultraviolet-X-ray connection in AGN outflows
The UNAM-KIAS Catalog of Isolated Galaxies
The underlying stellar absorption contribution to the primordial helium abundance determination
The Unifying Dark Fluid Model
The universal distribution of halo interlopers in projected phase space. Bias in galaxy cluster concentration and velocity anisotropy?
The Universal Einstein Radius Distribution from 10,000 SDSS Clusters
The Universal Faber-Jackson Relation
The universal galaxy cluster pressure profile from a representative sample of nearby systems (REXCESS) and the Y_SZ-M_500 relation
The Universal Gas Mass Fraction in Clusters of Galaxies
The Universal Initial Mass Function In The XUV Disk of M83
The universe is accelerating. Do we need a new mass scale?