From the equivalent widths of the main features of the K band spectra (the NaI, CaI and CO bandheads) we have derived the metallicities of the sources by means of the empirical scale obtained by Ramirez et al. (2000AJ....120..833R) and Frogel et al. (2001AJ....122.1896F) for luminous red giants. (2 data files).

Aims:The analysis of near infrared spectropolarimetric data at the internetwork in different regions on the solar surface could offer constraints that reject current modeling of these quiet areas. Methods: We present spectro-polarimetric observations of very quiet regions for different values of the heliocentric angle for the Fe i lines at 1.56 μm

We present near-infrared (1.15-2.50μm) medium-resolution (R = 1700) spectroscopy of a sample of 23 brown dwarf candidates in the young UpperSco association. We confirm membership of 21 brown dwarfs based on their spectral shape, comparison with field dwarfs and presence of weak gravity-sensitive features. Their spectral types range from M8 to L2

The properties of high-redshift quasar host galaxies are studied in order to investigate the connection between galaxy evolution, nuclear activity, and the formation of supermassive black holes. We combine new near-IR observations of three high-redshift quasars (2 1.5. Radio-quiet quasar hosts also follow a similar trend but at a lower average

The reliability of quiet-Sun magnetic field diagnostics based on the Fe I lines at 6302 Å has been questioned by recent work. Here we present the results of a thorough study of high-resolution multiline observations taken with the new spectropolarimeter SPINOR, comprising the 5250 and 6302 Å spectral domains. The observations were analyzed using

I have developed an IDL simulation of an electron multiplying L3 (low light level) technology CCD that includes the effects of clock induced charge and multiplication noise. This model allows observers interested in obtaining high time resolution photometry and spectroscopy of faint sources to compare more easily the gains in performance that can