Understanding the physics of the X-factor

Understanding the spiral structure of the Milky Way using the local kinematic groups

Unexpected Formation Modes of the First Hard Binary in Core Collapse

Unidentified Features in the Ultraviolet Spectrum of X Per

Unification of Luminous Type 1 Quasars through CIV Emission

Unification of Radio Galaxies and Their Accretion/Jet Properties

Uniform detection of the pre-main sequence population in the 5 embedded clusters related to the H\,II region NGC\,2174 (Sh2-252)

Unifying boxy bulge and planar long bar in the Milky Way

Universal Nonlinear Small-Scale Dynamo

Universal Scaling Function of Velocity Rotation in Spiral galaxies

Universality of young cluster sequences

Unravelling the origins of S0 galaxies using maximum likelihood analysis of planetary nebulae kinematics

Unresolved X-ray emission in M31 and constraints on progenitors of Classical Novae

Unstable $m=1$ modes of counter-rotating Keplerian discs

Unveiling Extragalactic Star Formation Using Radio Recombination Lines: An EVLA Pilot Study with NGC 253

Unveiling hidden properties of young star clusters: differential reddening, star-formation spread and binary fraction

Unveiling Sources of Heating in the Vicinity of the Orion BN/KL Hot Core as Traced by Highly Excited Inversion Transitions of Ammonia

Unveiling the molecular environment of the ring nebula RCW 78

Unveiling the physical properties and kinematics of molecular gas in the Antennae Galaxies (NGC 4038/9) through high resolution CO (J = 3-2) observations

Update on the Nature of Virgo Overdensity