We have analyzed observations with the Chandra X-ray Observatory of the diffuse emission by hot gas in 7 dwarf starburst galaxies, 6 edge-on starburst galaxies, and 9 Ultra Luminous Infrared Galaxies. These systems cover ranges of ∼ 10 4 in X-ray luminosity and several thousand in star formation rate and K-band luminosity (a proxy for stellar mass). Despite this range in fundamental parameters,...

We investigate radio-mode AGN activity among post-starburst galaxies from the Sloan Digital Sky Survey (SDSS) to determine whether AGN feedback may be responsible for the cessation of star formation. Based on radio morphology and radio loudness from the FIRST and NVSS data, we separate objects with radio activity due to an AGN from ongoing residual star formation. Of 513 SDSS galaxies with stro...

We examine the physical conditions of the molecular gas in the extremely red object (ERO), HR10 (J164502+4626.4, or [HR94] 10) at z = 1.44, as constrained by the recent detection of CO J + 1 → J, J = 1, 4 lines. The line ratios of such widely spaced CO transitions are very sensitive probes of gas excitation; in the case of HR10, they provide a rare opportunity to study the state of H2 gas in a ...

We present the first results of a new set of population synthesis models, which utilize the latest stellar evolutionary tracks, recent non-LTE atmosphere models which include stellar winds, and observed line strengths in WR spectra to predict the relative strengths of various WN and WC/WO emission features in the spectra of starburst galaxies. Our results will be used to derive accurate numbers...

During the 2007/2008 season, VERITAS was used for observations at E>200 GeV of several extragalactic nonblazar objects such as galaxy clusters, starburst and interacting galaxies, dwarf galaxies, and nearby galaxies. In these proceedings, we present preliminary results from our observations of dwarf galaxies and M87. Results from observation of other non-blazar sources are presented in separate...

The rotation curve of the small-mass starburst galaxy M82 has a steep nuclear rise, peaking at 200 pc radius, and then, declines in a Keplerian fashion. This rotation curve mimics that for a central bulge of spiral galaxies with high concentration of stellar mass. The declining rotation indicates that its extended disk mass is missing. In order to explain this peculiar rotation characteristics,...

We study 87 Extremely Red Objects (EROs), selected both to have color redder than R−[3.6] = 4.0, and to have confirmed spectroscopic redshifts. Together, these two constraints result in this sample populating a fairly narrow redshift range at 0.76 < z < 1.42. The key new ingredient included here is deep Spitzer Space Telescope InfraRed Array Camera (IRAC) data. Based on [3.6]− [8.0] color, we d...

We present observations of the 492 GHz [CI] emission for four individual giant molecular clouds in the Local Group galaxy M33 obtained with the James Clerk Maxwell Telescope. The average [CI] to CO J=1-0 integrated intensity ratio of 0.10± 0.03 is similar to what is observed in Galactic molecular clouds but smaller than what is seen in starburst galaxies. Similarly, the column density ratio N(C...

We present deep Hubble Space Telescope NICMOS near-infrared and WFPC2 optical imaging of a small region in the core of the distant rich cluster Cl 0939+4713 (z = 0.41). We compare the optical and near-infrared morphologies of cluster members and find apparent small-scale optical structures within the galaxies which are absent in the near-infrared. We conclude that strong dust obscuration is a c...

We report on observations of CO(1→0) emission from the chemically young starburst galaxy Mrk 109. These observations were part of a study to constrain the O2/CO ratio in metal–deficient galaxies, which were motivated by theoretical work that suggests the possible enhancement of the O2/CO ratio in chemically young systems. Five low metallicity (Z ≤ 0.5Z⊙) IRAS galaxies at redshifts z > 0.02 (req...