We present the identification and characterization of the optical counterpart to 2XMM J011942.7+032421, one of the most luminous and distant ultra-luminous X-ray sources (ULXs). The counterpart is located near a star-forming region in a spiral arm of the galaxy NGC 470 with u, g, and r magnitudes of 21.53, 21.69, and 21.71 mag, respectively. The

We present the results of optical photometry of the X-ray transient XTE J2123-058. CCD R-band images, have been obtained since 2 Jul until 29 Sep 1998. Following the behaviour of the XTE/ASM lightcurve, the system decline optically from the begining of August at approximately 0.1 mag/day. Despite the drop in luminosity, we observe a dramatic

An international collaboration of fourty scientists have been involved in multifrequency observations of the blazar OJ 287, as well as of a few other complementary objects, taken both photometrically and spectroscopically. We present the optical light curve of OJ 287 obtained between the fall of 1993 through the present. Over 1200 photometric

To asses stability against 1/f noise, the Low Frequency Instrument (LFI) on-board the Planck mission will acquire data at a rate much higher than the data rate allowed by the science telemetry bandwith of 35.5 Kbps. The data are processed by an on-board pipeline, followed on-ground by a decoding and reconstruction step, to reduce the volume of data

Aims: We explore the relations between physical and orbital properties of planets and properties of their host stars to identify the main observable signatures of the formation and evolution processes of planetary systems. Methods: We used a large sample of FGK dwarf planet-hosting stars with stellar parameters derived in a homogeneous way from the

Se presenta un análisis arqueoastronómico de la orientación definida por los muros del santuario de entrada del oppidum ibérico Cerro de las Cabezas (Valdepeñas, Ciudad Real), situado en la Oretania septentrional, así como de otros recintos pertinentes para el análisis. El resultado más relevante es que dos de los muros perimetrales del santuario