UNJ1025−0040 is a quasar at z = 0.6344 that shows an extremely bright post starburst population of age ∼ 400 Myr (Brotherton et al. 1999). Images of UNJ1025−0040 show a nearly stellar object 4. 2 SSW of the quasar. We present imaging and spectroscopy that confirm that this object is a companion galaxy at redshift z = 0.6341. We estimate an age of ∼ 800 Myr for the dominant stellar population in...

If cosmic ray protons interact with gas at roughly the mean density of the interstellar medium in starburst galaxies, then pion decay in starbursts is likely to contribute significantly to the diffuse extra-galactic background in both γ-rays and high energy neutrinos. We describe the assumptions that lead to this conclusion and clarify the difference between our estimates and those of Stecker (...

Models of galaxy formation invoke the major merger of gas-rich progenitor galaxies as the trigger for significant phases of black hole growth and the associated feedback that suppresses star formation to create red spheroidal remnants. However, the observational evidence for the connection between mergers and active galactic nucleus (AGN) phases is not clear. We analyze a sample of low-mass ear...

ASTRONOMY AND ASTROPHYSICS Photometric studies of some starburst galaxies. Abstract. We present the results of a detailed morphological analysis of ten starburst galaxies selected from the Markarian catalogue of uv-excess objects. CCD surface photometry of these galaxies was carried out based on observations made in B, V (Johnson) and R, I (Kron-Cousins) band passes. We present the radial varia...

We study the correlation between the radio, mid-infrared, and far-infrared properties for a sample of 28 blue compact dwarf (BCD) and low-metallicity star-forming galaxies observed by Spitzer. We find that these sources extend the same far-infraredYtoYradio correlation typical of star-forming late-type galaxies to lower luminosities. In BCDs, the 24 m (or 22 m) mid-infraredYtoYradio correlation...

In this paper we use neutral hydrogen (H I) and optical spectroscopic observations to compare the timescales of a merger event, starburst episode and radio-AGN activity in the radio galaxy B2 0648+27. We detect a large ring-like structure of H I in emission around the early-type host galaxy of B2 0648+27 (M H I = 8.5 × 10 9 M ⊙ , diameter = 190 kpc). We interpret this as the result of a major m...

We present multi-fiber spectroscopy and broadband imaging of early-type galaxies in five nearby rich clusters of galaxies. The main purpose was to look for “abnormal” spectrum galaxies (i.e., post-starburst galaxies which have strong Balmer absorption lines and emission line galaxies) in nearby clusters that are similar to those found by Caldwell et al. (1993) in the Coma cluster. Three of the ...

We present a new analysis of the dust obscuration in starburst galaxies at low and high redshift. This study is motivated by our unique sample of the most extreme UV-selected starburst galaxies in the nearby universe (z < 0.3), found to be good analogs of high-redshift Lyman Break Galaxies (LBGs) in most of their physical properties. We find that the dust properties of the Lyman Break Analogs (...

Post-starburst (or "E+A") galaxies trace the fastest and most dramatic processes in galaxy evolution. Recent work studying evolution of through this phase have revealed insights on how undergo structural stellar population changes as well role various feedback mechanisms. In review, I summarize recent identifying post-starburst galaxies; tracing cosmic time; measuring populations, on-going star...

SBS0335-052 is a blue compact dwarf galaxy (BCD) with one of the lowest known metallicities, Z∼Z⊙/41, making it a local example of how primordial starburst galaxies and their precursors might appear. A spectrum obtained with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope clearly shows silicate absorption features, emission lines of [SIV] and [NeIII], and puts strong upper limits...