Aims:We aim to identify the nature of several objects previously catalogued as ultra-luminous X-ray (ULX) source candidates. Methods: Long-slit spectroscopy of the optical counterparts has been carried out. Results: The eight objects are at higher redshift than their putative parent galaxies. Conclusions: It is found that these eight previously

Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron

FRIDA will be a common-user near infrared imager and integral field spectrograph covering the wavelength range from 0.9 to 2.5 microns. Primary observing modes driven the instrument design are two: direct imaging and integral field spectroscopy. FRIDA will be installed at the Nasmyth-B platform of the Gran Telescopio Canarias (GTC) behind the GTC

High-resolution spectra of the program stars were obtained during the period 2002 December-2004 June at the Harlan J. Smith 2.7-m telescope of the W.J. McDonald Observatory, using the 2dcoude echelle spectrometer with a 2048x2048 Tektronix CCD as detector. (2 data files).

We study the emergence of magnetic flux at very small spatial scales (less than 2") in the quiet-Sun internetwork. To this aim, a time series of spectropolarimetric maps was taken at disk center using the instrument SP/SOT on board Hinode. The LTE inversion of the full Stokes vector measured in the Fe I 6301 and 6302 Å lines allows us to retrieve

OSIRIS (Optical System for Imaging and low/intermediate-Resolution Integrated Spectroscopy) and EMIR (InfraRed MultiObject Spectrograph) are instruments designed to obtain images and low resolution spectra of astronomical objects in the optical and infrared domains. They will be installed on Day One and Day Two, respectively, in the Nasmyth focus