The Morphology of 9 Radio-selected Faint Galaxies from deep HST Imaging

Using the HST WFPC2 we perform deep I-band imaging of 9 radio-selected (limit 14 microJanskys at 8.5 GHz) faint galaxies from Roche, Lowenthal and Koo (2002). Two are also observed in V. Six of the galaxies have known redshifs of 0.4<z<1.0. Radial intensity profiles indicate that 7 are disk galaxies and 2 are bulge-dominated. Four of the six with redshifts have a high optical surface brightness compared to typical disk galaxies. Two of the 9 galaxies are in close interacting pairs, another two are very asymmetric and three have large, luminous rings resembling the collisional starburst rings in the Cartwheel galaxy. In most of these galaxies the high radio luminosities are probably the result of interaction-triggered starbursts. The mixture of observed morphologies suggests that enhanced radio luminosities often persist for >0.2 Gyr, to a late stage of the interaction. One of these 9 galaxies may be an exception in that it is a large red elliptical and its strong radio emission is more likely to be from an obscured AGN.Comment: 12 pages, latex, 8 figures, accepted for publication in MNRA

Dynamics of Lyman Break Galaxies and Their Host Halos

We present deep two-dimensional spectra of 22 candidate and confirmed Lyman break galaxies (LBGs) at redshifts

Introduction: Going Public

The period in which the public history movement has developed has been one of considerable change. This has been a result of the passing of post-war generations, the effects wrought by continuing internal and external conflicts, the globalisation of economies, the emergence of new media forms and the major impact of the digital revolution. This has seen significant shifts in the transmission, reception and practice of history

Parallel Implementation of the PHOENIX Generalized Stellar Atmosphere Program. III: A parallel algorithm for direct opacity sampling

We describe two parallel algorithms for line opacity calculations based on a local file and on a global file approach. The performance and scalability of both approaches is discussed for different test cases and very different parallel computing systems. The results show that a global file approach is more efficient on high-performance parallel supercomputers with dedicated parallel I/O subsystem whereas the local file approach is very useful on farms of workstations, e.g., cheap PC clusters.Comment: 19 pages, ApJ Suppl in press (July 2001), 6 figures. Also available at http://phoenix.physast.uga.edu