We examine the possibility of the active galactic nucleus (AGN) obscuration by dusty gas clouds that spurt out from circumnuclear starburst regions. For the purpose, the dynamical evolution of gas clouds is pursued, including the effects of radiation forces by an AGN as well as a starburst. Here, we solve the radiative transfer equations for clouds, taking into consideration the growth of cloud...

Spectra have been obtained with the Infrared Spectrograph ( IRS) on the Spitzer Space Telescope for 20 sources in the Lockman Hole field of the SWIRE survey. The sample is divided between sources with indicators of an obscured AGN, based primarily on X-ray detections of optically faint sources, and sources with indicators of a starburst, based on optical and near-infrared spectral energy distri...

The peak star formation intensity in starburst galaxies does not vary significantly from the local universe to redshift z∼6. We arrive at this conclusion through new surface brightness measurements of 47 starburst galaxies at z≃5−6, doubling the redshift range for such observations. These galaxies are spectroscopically confirmed in the Hubble Ultra Deep Field (HUDF) through the GRism ACS progra...

A summary of starburst luminosities based on PAH features is given for 243 starburst galaxies with 0 < z < 2.5, observed with the Spitzer Infrared Spectrograph. Luminosity νLν(7.7μm) for the peak luminosity of the 7.7μm PAH emission feature is found to scale as log[νLν (7.7μm)] = 44.63(±0.09) + 2.48(±0.28) log(1+z) for the most luminous starbursts observed. Empirical calibrations of νLν(7.7μm) ...

We model the constraints set on the evolution of dusty starburst galaxies by the current deep extragalactic surveys performed in the far-infrared with Spitzer , and at radio wavelengths with the VLA. Our models fit the number counts in all the available spectral bands well, and also provide a reasonably close match to the redshift distribution of the Spitzer detections. We find: 1.) dusty starb...

We compare the arcsecond-scale circumnuclear radio continuum properties between five Seyfert and five starburst galaxies, concentrating on the search for any structures that could imply a spatial or causal connection between the nuclear activity and a circumnuclear starburst ring. No evidence is found in the radio emission for a link between the triggering or feeding of nuclear activity and the...

We examine the power source of 41 local Ultraluminous Infrared Galaxies (ULIRGs) using archival infrared (IR) and optical photometry. We fit the observed Spectral Energy Distributions (SEDs) with starburst and AGN components; each component being drawn from a family of templates. We find all of the sample require a starburst, whereas only half require an AGN. In 90% of the sample the starburst ...

Loeb and Waxman have argued that high energy neutrinos from the decay of pions produced in interactions of cosmic rays with interstellar gas in starburst galaxies would be produced with a large enough flux to be observable. Their model is reexamined here and it is shown that the the neutrino flux from starburst galaxies, even given the various assumptions made by them, is more than an order of ...

We present models of the 1.4 GHz to 350 GHz spectral index, α 1.4 , for starburst galaxies as a function of redshift. The models include a semi-analytic formulation, based on the well quantified radio-to-far infrared correlation for low redshift star forming galaxies, and an empirical formulation, based on the observed spectrum of the starburst galaxies M82 and Arp 220. We compare the models to...

We present the first determination of the 15 m luminosity function of galaxies from the European Large Area ISO Survey (ELAIS) southern fields. We have adopted a new criterion to separate the quiescent, nonevolving and the starburst, evolving populations based on the ratio of mid-infrared to optical luminosity. Strong evolution is suggested by our data for the starburst galaxy population, while...