We report on the results of optical follow-up observations of the counterpart of the gamma-ray burst GRB 970508, starting 7 hr after the event. Multicolor U-, B-, V-, Rc-, and Ic-band observations were obtained during the first three consecutive nights. The counterpart was monitored regularly in Rc until ~4 months after the burst. The light curve

We present the results of a high resolution (0.27'' px(-1) ) near-infrared H band (1.65 μm) imaging survey of a complete sample of 20 flat spectrum radio quasars (FSRQ) extracted from the 2Jy catalogue of radio sources (Wall & Peacock 1985). The observed objects are intrinsically luminous with median M(B) =3D -25.5. The median redshift of the

Observations of the Local Arm have been carried out in the near-infrared with the 1.5 m ``Carlos Sanchez'' telescope in Tenerife. A model of the disc with adjustable parameters fitted to reproduce the DIRBE-COBE survey, has been subtracted from the observational data in order to obtain a clean map of the Local Arm, uncontaminated by other

The blazar 3C 279, one of the brightest identified extragalactic objects in the gamma -ray sky, underwent a large (factor of ~10 in amplitude) flare in gamma -rays toward the end of a 3 week pointing by Compton Gamma Ray Observatory (CGRO), in 1996 January-February. The flare peak represents the highest gamma -ray intensity ever recorded for this

Since its discovery in 1992, the superluminal X-ray transient GRS 1915+105 has been extensively observed in an attempt to understand its behavior. We present here first results from a multiwavelength campaign undertaken from 1996 July to September. This study includes X-ray data from the RXTE All Sky Monitor and BATSE, two-frequency data from the

La tesis presenta los resultados del experimento Bartol-IAC sobre medidas de la anisotropía en el Fondo Cósmico de Microondas. Estas observaciones se realizaron en los meses de Junio y Julio de 1994 en el Observatorio del Teide. Se observó la región del cielo a delta=+40 grados en cuatro bandas a lamda=3,3; 2,1; 1,3 y 1,1 mm. En la tesis e han