AAS 201st Meeting, January, 2003
Session 52. Galaxy Evolution and Surveys: Observations and Interpretation
Poster, Tuesday, January 7, 2003, 9:20am-6:30pm, Exhibit Hall AB

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[52.05] H I Evolutionary Studies of IR-Selected AGN

S. L. Stevenson (Wesleyan University), L. K. Hunt (IRA/Firenze-CNR, Firenze, Italy), T. Ghosh, J. Eder (NAIC/Arecibo Observatory)

We present a comparative analysis of the evolutionary properties of a sample of \approx 27 Seyfert, 13 Starburst, and 14 non-active galaxies selected from the Extended 12-Micron Galaxy Sample (E12GS). The E12GS was used in an effort to minimize the contribution of any active nucleus to the total flux density emitted by the object, allowing us to choose objects with similar host properties (i.e. morphology, surface brightness) but different activity types. For the objects in our subsample, both radio (21-cm) and infrared (12 and 2\mum) data is available. H I information is derived from L-band observations performed at the Arecibo Observatory, combined with archival data from the HIPASS and LEDA databases, while infrared information is drawn from 2MASS. We have used the \lambda 21-cm HI spectra of our objects to determine the effects of evolution on the physical properties of galaxies as a function of activity type. The effects of the infrared selection criterion are examined; the non-active subsample is found to be globally similar to previous optically-selected galaxy samples in parameters such as H I mass fraction and central surface brightness. We construct evolutionary diagrams - e.g., total (dynamical) mass vs. H surface brightness, mass-to-light ratio vs. H I mass fraction - for each of our subsamples, and compare evolutionary effects between different activity types and evaluate them against those of the non-active control sample.

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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.