We present the results of a high-spatial-resolution study of the line emission in a sample of z=3.1 Lyman-Alpha-Emitting Galaxies (LAEs) in the Extended Chandra Deep Field-South. Of the eight objects with coverage in our HST/WFPC2 narrow-band imaging
, two have clear detections and an additional two are barely detected (~2-sigma). The clear detections are within ~0.5 kpc of the centroid of the corresponding rest-UV continuum source, suggesting that the line-emitting gas and young stars in LAEs are spatially coincident. The brightest object exhibits extended emission with a half-light radius of ~1.5 kpc, but a stack of the remaining LAE surface brightness profiles is consistent with the WFPC2 point spread function. This suggests that the Lyman Alpha emission in these objects originates from a compact (<~2 kpc) region and cannot be significantly more extended than the far-UV continuum emission (<~1 kpc). Comparing our WFPC2 photometry to previous ground-based measurements of their monochromatic fluxes, we find at 95% (99.7%) confidence that we cannot be missing more than 22% (32%) of the Lyman Alpha emission.
We present line-strength measurements for 74 early-type galaxies in the core of the Coma cluster reaching down to velocity dispersions, sigma, of 30 km/s. The index-sigma relations for our sample, including galaxies with sigma<100 km/s (low-sigma), d
iffer in shape depending on which index is used. We notice two types of relations for the metallic indices: one showing a break in the slope around ~100 km/s, and another group with strong linear relations between an index and log sigma. We find no connection between the behavior of index-sigma relations with either alpha- or Fe-peak elements. However, we find indications that the relations are tighter for indices which do not depend on the micro-turbulent velocities of stellar atmospheres. We confirm previous results that low-sigma galaxies including dE/dS0s are on average younger, less metal rich, and have lower [alpha/Fe] in comparison to E/S0s. Our data show that these trends derived for high-sigma galaxies extend down to dE/dS0s. This is a factor of ~2 lower in sigma than previously published work. We confirm that the observed anti-correlation between age and metallicity for high-sigma galaxies is consistent with the effects of correlated errors. Low-sigma galaxies also show a similar relation between age and metallicity as a result of correlated errors. However, they are offset from this relationship so that, on average, they are less metal rich and younger than their high-sigma counterparts.
