We analyze high signal-to-noise spectra for 14 globular clusters (GCs) in the Sombrero galaxy, NGC 4594 (=M104), obtained with the LRIS spectrograph on the Keck I telescope. We find generally good agreement between spectroscopic metallicities and previous photometric metallicities based on V-I colors. Further, we use measurements of various Balmer

The IRIS network has been operated continuously since July 1st 1989. To date, it has acquired more than a complete solar cycle of full-disk helioseismic data which has been used to constrain the structure and rotation of the deep solar interior. However, the duty cycle of the network data has never reached initial expectations. To improve this

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We present the first infrared (IR) light curves in the J, H and K bands of δ Lib obtained at different observing runs from 1994 to 1998. These IR light curves, showing a secondary minimum much deeper than in visual bands, have been analysed in order to determine a new set of physical parameters. A new program using the Roche geometry, and stellar

We investigate the diagnostic potential of polarimetric measurements with filtergraph instruments. Numerical simulations are used to explore the possibility of inferring the magnetic field vector, its filling factor, and the thermodynamics of model atmospheres when only a few wavelength measurements are available. These simulations assume the

Through observations and modeling, we demonstrate how the recently discovered large-scale bar in NGC 5248 generates spiral structure that extends from 10 kpc down to 100 pc, fuels star formation on progressively smaller scales, and drives disk evolution. Deep inside the bar, two massive molecular spirals cover nearly 180° in azimuth, show streaming