We have developed an automatic procedure to determine Teff and log g from the comparison of observational data with their theoretical values. After a description of the method we compare our results for a sample of 100 O-type stars with the classifications of Conti and Walborn and with the determinations of Morrison by photometric indices. The

A case of cancellation of magnetic fields is observed during the decay of a small active region. Three different sources of information were simultaneously used: high resolution magnetograms, chromospheric Ca II filtergrams and transverse velocity fields. A magnetic structure is apparently dragged to the network by the supergranular velocity field

We present near-infrared integral field spectroscopy data obtained with Very Large Telescope/Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI) of `the Teacup galaxy'. The nuclear K-band (1.95-2.45 μm) spectrum of this radio-quiet type-2 quasar reveals a blueshifted broad component of FWHM ˜ 1600-1800 km s-1 in the hydrogen

Observations taken at Calar Alto and Loiano led to the possible identification of the GRB 971227 optical counterpart. Details on the observations are presented.

The Kepler mission will provide a huge amount of asteroseismic data during the next few years, among which hundreds of solar-like stars will be targeted. The amount of stars and their observation length represent a step forward in the comprehension of the stellar evolution that has already been initiated by CoRoT and MOST missions. Up to now, the

Recently the readout of the MAGIC telescopes has been upgraded to a new system based on the Domino Ring Sampler version 4 chip. We present the analysis techniques and the signal extraction performance studies of this system. We study the behavior of the baseline, the noise, the cross-talk, the linearity and the time resolution. We investigate also