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Images of 7 Compact groups of galaxies (CG) were obtained using the 2.1m telescope in San Pedro Martir (B.C. Mexico) equipped with the NIR camera CAMILA. The NIR images trace the mass of the galaxies, through the oldest and more evolved stellar populations. The goal of this project is to search for evidence of morphological perturbations correlated with the level of activity (AGN or star formation) of the galaxies. We find that the level of perturbation is well correlated with activity observed in optical spectrocopy (Coziol et al. 2004). Evidence for perturbations decreases from more active groups to less active groups, confirming the classification. Our analysis suggests that galaxies in more active groups are undergoing important transformations due to interaction and merging and that the whole groups is on a merger path. Galaxies in less active CG have gone through similar processes in the recent past and are either in a final merging phase or in equilibrium due to a more massive halo of dark matter.
We are using the 2dF spectrograph to make a survey of all objects (`stars and `galaxies) in a 12 sq.deg region towards the Fornax cluster. We have discovered a population of compact emission-line galaxies unresolved on photographic sky survey plates
We present a near-infrared (NIR) imaging study of barred low surface brightness (LSB) galaxies using the TIFR near-infrared Spectrometer and Imager (TIRSPEC). LSB galaxies are dark matter dominated, late type spirals that have low luminosity stellar
Bayesian statistical calculations and linear-bisector calculations for obtaining Cepheid distances and radii by the infrared surface brightness method have been compared for a set of 38 Cepheids. The distances obtained by the two techniques agree to
The Hubble Ultra Deep Field (HUDF) contains a significant number of B, V and i-band dropout objects, many of which were recently confirmed to be young star-forming galaxies at z~4-6. These galaxies are too faint individually to accurately measure the
We measured infrared surface brightness fluctuation (SBF) distances to an isotropically-distributed sample of 16 distant galaxies with redshifts reaching 10,000 km/s using the near-IR camera and multi-object spectrometer (NICMOS) on the Hubble Space