We combine a number of powerful mathematical techniques to produce an effective method for treating multidimensional radiative transfer problems in complex atomic models without assuming local thermodynamic equilibrium (LTE). The approach is so efficient that multilevel two-dimensional (2D) modeling can now be performed with no more than a

An increasing number of both photometric and spectroscopic observations over the last years have shown the existence of distinct sub-populations in many Galactic globular clusters and shattered the paradigm of globulars hosting single, simple stellar populations. These multiple populations manifest themselves in a split of different evolutionary

We report on a near-infrared adaptive optics imaging survey of 31 young brown dwarfs and very low mass (VLM) stars, 28 of which are in the Chamaeleon I star-forming region, using the ESO Very Large Telescope. We resolve the suspected 0.16'' (~26 AU) binary Cha Hα 2 and present two new binaries, Hn 13 and CHXR 15, with separations of 0.13'' (~20 AU)

We characterized the broad-band X-ray spectra of Swift J1745-26 during the decay of the 2013 outburst using INTEGRAL ISGRI, JEM-X and Swift XRT. The X-ray evolution is compared to the evolution in optical and radio. We fit the X-ray spectra with phenomenological and Comptonization models. We discuss possible scenarios for the physical origin of an

We present multiwavelength monitoring of the Galactic microquasar GRS1915+105 in the infrared, X-ray, and radio bands using observations from the Whipple Observatory 1.2-m, Lowell Observatory 1.8-m, Palomar 5-m, and the United Kingdom Infrared telescopes, the Rossi X-ray Timing Explorer All-Sky Monitor, and the Green Bank Interferometer during May

The unprecedented spatial resolution of Chandra is allowing reliable identifications of the counterparts of M31 X-ray sources at other wavelengths. Comparisons with Hubble Space Telescope data, recent ground-based Local Group Survey data, and Very Large Array radio data reveal many interesting objects. These include newly-resolved X-ray/optical