A catalogue of galaxies with extremely red colours (R-J≥5), covering 8.43 square degrees has been selected from optical and near-infrared data. Based on their bright near-infrared magnitude and their very red colour, these objects are likely to be very massive galaxies with little or no ongoing star formation. We have derived a surface density of 0

Breaking age/metallicity degeneracy ([19], [1]) is crucial for understanding stellar populations in elliptical galaxies. Spectroscopic properties, such as line strength, can partially break age/metallicity degeneracy. Reference [19] found that Hβ index, defined in [4] (Lick indices), is relatively sensitive to luminosity-weighted age of galaxies

This work presents the first quiet Sun spectropolarimetric observations carried out in the visible and the infrared (IR) simultaneously. The Fe I lines at 6301.5, 6302.5, 15648, and 15652 Å were observed co-spatially, and at the same time (with a time lag of only 1 minute), with high sensitive spectropolarimeters operated in two different

The ratio of the intensities is related to the emph{equivalent width}, W, of the spectral lines, which shape is approximated to a Voigt function resulting from the convolution of a Lorentzian (Stark and Van der Waals effects) and Gaussian (Doppler effect and optical broadening) profiles. Thus, we have studied the influence of the self-absorption

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