Based on the Sérsic parameters, obtained by fitting pixel to pixel their deep optical galaxy images, the structural properties of the underlying stellar host of a sample of 20 star-forming dwarf galaxies have been analyzed. Our 2D technique has been improved to derive reliable Sérsic models, such as the proper isolation of the starburst emission

We have made B, V, and I-band observations of satellite galaxies which lie around isolated disk galaxies, using the satellite sample of Zaritsky et al. (1997). We present 3D light profiles of the centers of these satellites, and discuss how we plan to use the profiles to study the survival or disruption of satellites in minor mergers, an issue that

We present with outstanding detail an extragalactic perspective of an extended stellar tidal stream wrapping around the edge-on, spiral galaxy NGC 5907. Our deep images reveal for the first time a large scale complex of arcing loops that is an excellent example of how a low-mass satellite accretion can produce a interweaved, rosette-like structure

Seismology of single δ Scuti stars has mainly been inhibited by failing to detect many of the theoretically predicted pulsation modes, resulting in difficulties with mode identification. Theoretical and observational advances have, however, helped to overcome this problem, but the following questions then remain: do we know enough about the star to

Based on spectrophotometric observations from the Guillermo Haro Observatory (Cananea, Mexico), a study of the spectral properties of the complete sample of 24 blue straggler stars (BSs) in the old Galactic open cluster M67 (NGC 2682) is presented. All spectra, calibrated using spectral standards, were recalibrated by means of photometric

The present paper discusses the seismic modelling of five δ Scuti stars belonging to the Praesepe cluster. Linear analysis is confronted with observations, using refined descriptions for the effects of rotation on the determination of the global stellar parameters and on the adiabatic oscillation frequency computations. A single, complete, and