The proper characterization of the turbulence structure in an astronomical site requires a statistical analysis of the refractive index structure constant, CN2(h). Our team has been monitoring this variable since November 2002 at the Teide Observatory (Tenerife, Canary Islands, Spain). We have derived the seasonal evolution of turbulence structure

This paper presents the first results of an Hα imaging survey of galaxies in the central regions of the A2151 cluster. A total of 50 sources were detected in Hα, from which 41 were classified as secure members of the cluster and 2 as likely members based on spectroscopic and photometric redshift considerations. The remaining seven galaxies were

HH 202 was observed on 2003 March 30 at Cerro Paranal Observatory, Chile, using the UT2 (Kueyen) of the Very Large Telescope (VLT) with the Ultraviolet Visual Echelle Spectrograph (UVES). (1 data file).

We report on the results of two coordinated multiwavelength campaigns that focused on the blazar Markarian 421 during its 2006 and 2008 outbursts. These campaigns obtained UV and X-ray data using the XMM-Newton satellite, while the gamma-ray data were obtained utilizing three imaging atmospheric Cerenkov telescopes, the Whipple 10 m telescope and

Based on MAGIC observations from 2007 June to July, we have obtained an integral upper limit to the VHE energy emission of the globular cluster M13 of F(E>200 GeV) 5.1 × 10-12 cm-2 s-1, and differential upper limits for E > 140 GeV. Those limits allow us to constrain the population of millisecond pulsars within M13 and to test models for

RXTE PCA Bulge scans detected activity of what appeared to be a known source. However, based on the results presented below, and the report of a new INTEGRAL source IGR J17511-305 (Baldovin et al. ATEL #2196), the activity detected by RXTE is due to a new 245 Hz X-ray pulsar. The source was initially detected on 2009-09-11 at 17:50 UT as a rising