Using HST/ACS broad- and narrow-band (Hα) images of M51 we have examined the ionizing radiation budget in a set of luminous H II regions in a spiral arm between 5 kpc and 11 kpc from the center. The extinctions within the regions were estimated, and a mean value for the differential extinction coefficient, RV, of 3.3, similar to the Galactic value

We present two-dimensional Hα velocity fields for ten well-defined nuclear rings observed with the DensePak fiber-optic array on the KPNO WIYN telescope. In this paper, we present detailed results for two of those rings, in NGC 1530 and NGC 4314. We conclude that in general regions of enhanced Hα, thus massive star formation, in the nuclear rings

We report on XMM-Newton and Chandra observations of the globular cluster NGC 2808. We detect one quiescent low mass X-ray binary of the 3±1 expected, if these systems are formed through encounters, and we show evidence for the presence of 20±10 bright cataclysmic variables in the core with a luminosity above 4×1031 erg s-1. We also review the

The fact that another SN Ia, SN 2002bo, exploded in the same galaxy a few months before SN 2002cv, makes available pre-discovery optical and near-IR (NIR) data and hence templates for photometric measurements via image subtraction. SN 2002cv was observed for seven months, from day 10.7 to +205.9 relative to I-band maximum light. Here, we present

The fact that another SN Ia, SN 2002bo, exploded in the same galaxy a few months before SN 2002cv, makes available pre-discovery optical and near-IR (NIR) data and hence templates for photometric measurements via image subtraction. SN 2002cv was observed for seven months, from day 10.7 to +205.9 relative to I-band maximum light. Here, we present

We observed a new cataclysmic variable (CV) SDSS J080434.20+510349.2 to study the origin of long-term variability found in its light curve. Multi-longitude, time-resolved, photometric observations were acquired to analyze this uncommon behavior, which has been found in two newly discovered CVs. This study of SDSS J080434.20+510349.2 concerns