4 papers · 1 filter
Laser Guide Star Adaptive Optics without Tip-tilt
R. Davies, S. Rabien, C. Lidman +8
Adaptive optics (AO) systems allow a telescope to reach its diffraction limit at near infrared wavelengths. But to achieve this, a bright natural guide star (NGS) is needed for the…
Detections of Warm-Hot Intergalactic Medium
L. Zappacosta, R. Maiolino, F. Mannucci +3
Several popular cosmological models predict that most of the baryonic mass in the local universe is located in filamentary and sheet-like structures associated with groups and clus…
Optically dim counterparts of hard X-ray selected AGNs
R. Maiolino, M. Salvati, L. A. Antonelli +9
We present near-IR photometry and imaging observations of a small sample of sources identified in the BeppoSAX 5-10 keV survey (HELLAS) which resolves ~ 20-30% of the X-ray backgro…
New Clues on the Nature of Extremely Red Galaxies
A. Cimatti, E. Daddi, S. di Serego Alighieri +7
We present near-infrared VLT-UT1+ISAAC spectroscopy of a sample of 9 extremely red galaxies (ERGs) with R-K>5 and K<19.0. Neither strong emission lines (F_lim<1-5 10^{-16} erg s^{-…