We report the detection of an orbital period decay of dot{P}=-1.83+/- 0.66 ms yr-1 in the black hole X-ray binary XTE J1118+480. This corresponds to a period change of -0.85 ± 0.30 μs per orbital cycle, which is ~150 times larger than expected from the emission of gravitational waves. These observations cannot be reproduced by conventional models

Extremely low mass (ELM) white dwarfs (WDs) with masses 0.25 M &sun; are rare objects that result from compact binary evolution. Here, we present a targeted spectroscopic survey of ELM WD candidates selected by color. The survey is 71% complete and has uncovered 18 new ELM WDs. Of the seven ELM WDs with follow-up observations, six are short-period

We use ˜2000 galaxies from PM2GC (Calvi, Poggianti & Vulcani 2011a) belonging to different environments to show how the fractions of different galaxy morphological types vary with global environment and as function of galaxy stellar mass at low redshift. Considering mass-limited galaxy samples with log10M★/M⊙≥ 10.25, we find a smooth increase

Aims: We present a determination of the intrinsic colors and ages of galaxies at very high redshift, in particular old galaxies (OGs) within extremely red objects (EROs). To date, the definition of EROs has been restricted to objects with z 2.5, however, here we consider objects with the same properties but shifted to higher redshifts (z > 2.5)

The Advanced X-ray Spectroscopic Imaging Observatory (AXSIO) is a NASA facility class X-ray observatory which can carry out many of the science goals of the International X-ray Observatory as outlined in the NWNH Astro2010 Decadal Survey. Studies of the mission configuration and science reach will inform NASA technology investments over the next

We present the first investigation of the Blue Straggler star (BSS) population in two isolated dwarf spheroidal galaxies of the Local Group, Cetus and Tucana. Deep Hubble Space Telescope/Advanced Camera for Surveys photometry allowed us to identify samples of 940 and 1214 candidates, respectively. The analysis of the star formation histories of the