In the last 12 years NGC 2770 hosted 2 standard supernovae (SNe) and one X-ray transient event (SN2008D) similar to a Gamma-Ray Burst (GRB). Given the close (27 Mpc) distance of NGC 2770, we could resolve with the OSIRIS tunable filter (TF) the 3 explosion sites in Hα. We also show Hα data of its satellite galaxy NGC 2770B, one of the least

The young massive cluster Cyg OB2 is the closest massive star forming region to the Sun, with hundreds of OB members, and then the best target in the Milky Way to study the feedback of massive stars on the star formation process. To study in detail the stellar population of such a unique target, Cyg OB2 has been observed with GTC/OSIRIS and Chandra

The hardware of the OSIRIS instrument is nearly complete. The instrument commissioning will continue with the validation of the remaining observing modes that are still pending. In the present contribution, the instrument status and the tasks to be tackled in the nearby future will be briefly described.

OB stars are very active actors shaping their environment and contributing to the chemical and dynamical evolution of their host galaxies. Accurate analyses of massive stars are thus a key ingredient in our interpretation of the light coming from the Milky Way and nearby galaxies. These analyses rely in the use of state-of-the-art model atmospheres

Quasars belong to the most energetic phenomena in the universe. Physical processes at the origin of them can be explained in the framework of the AGN unified scenario. The unified scenario predicts two classes of quasars, obscured and unobscured ones, depending on the orientation of the dusty torus which surrounds the central supermassive black

O Vz stars are defined as those O-type stars displaying He II 4686 absorption line stronger than other He line in the blue spectral region. These stars have been hypothesized on spectroscopic grounds to be O-type stars on or close to the Zero-Age-Main-Sequence (ZAMS), also having weaker winds than normal O V stars. We have tested these hypothesis