We discuss V and R band photometry for 67% of the Sullivan et al. (2000) SA57 ultraviolet-selected galaxy sample. In a sample of 176 UV-selected galaxies, Sullivan et al. (2000) find that 24% have (UV-B) colors too blue for consistency with starburst spectral synthesis models. We propose that these extreme blue, UV excess galaxies are Wolf-Rayet (WR) galaxies, starburst galaxies with strong UV ...

Radio continuum observations are a probe of star formation in galaxies, and are unaffected by dust extinction. Observations of the distant rich cluster Cl 0939+4713 have detected radio galaxies classified as post-starburst (“k+a”) on the basis of their optical spectra, and presumably this situation arises from heavily dust-obscured star formation (Smail et al. 1999). We present the results of a...

We present a new technique for accurately determining the ages of starbursts in post-starburst galaxies. In particular, it uses the strength of the Ca II H + H absorption feature relative to that of Ca II K to separate the e ects of burst strength from burst age in a spectrum comprised of a post-starburst population and an underlying old galaxy population. The technique is based on comparing th...

As a logical next step in improving the radio-to-submm spectral index as a redshift indicator (Carilli & Yun), we have investigated a technique of using the entire radio-to-FIR spectral energy distribution (SED) for deriving photometric redshifts for dusty starburst galaxies at high redshift. A dusty starburst SED template is developed from theoretical understanding on various emission mechanis...

It is known that the class of luminous starburst galaxies tends to have higher R =CO(J=1– 0)/CO(J=1–0) integrated line intensity ratios (R > 20) than normal spiral galaxies (R ∼ 10). Since most previous studies investigated only R, it remains uncertain whether the luminous starburst galaxies are overabundant in CO or underabundant in CO. Here we propose a new observational test to examine this ...

We present a detailed analysis of the spectroscopic catalog of galaxies in 10 distant clusters from Dressler et al. (1999, D99). We investigate the nature of the different spectral classes defined by D99 including star forming, post–starburst and passive galaxy populations, and reproduce their basic properties using our spectral synthesis model. We attempt to identify the evolutionary pathways ...

Averaged spectral energy distributions (SEDs) of active and starburst galaxies from the 12μm sample in the Local Universe and quasars, from an optically selected sample at a mean redshift 〈z〉=0.7 are built from optical, near-IR and far-IR (IRAS and ISO) photometric observations. These SEDs are then used to predict at various redshifts the number of Seyfert type 1 and type 2, starburst, normal g...

With a goal toward deriving the physical conditions in external galaxies, we present a survey of the formaldehyde emission in a sample of starburst systems. By extending a technique used to derive the spatial density in star formation regions in our own Galaxy, we show how the relative intensity of the 110 − 111 and 211 − 212 K-doublet transitions of H2CO can provide an accurate densitometer fo...

We present long slit spectra and multi-color CCD images which demonstrate that the strong star formation episodes that occurred in the post-starburst galaxies in the Coma Cluster and two eld galaxies were not restricted to the central regions of the galaxies. Rather, the remnant young stars from the starbursts are found to be distributed over a large radius, though changes in the relative stren...

We present a detailed analysis of the spectroscopic catalog of galaxies in 10 distant clusters from Dressler et al. (1999, D99). We investigate the nature of the diierent spectral classes deened by D99 including star forming, post{starburst and passive galaxy populations, and reproduce their basic properties using our spectral synthesis model. We attempt to identify the evolutionary pathways be...