Star-Formation Histories of Luminous Starburst Galaxies

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Session 119 -- Starbursts and Seyfert 2s
Oral presentation, Saturday, January 15, 10:15-11:45, Crystal Forum Room (Crystal City Marriott)

[119.01] Star-Formation Histories of Luminous Starburst Galaxies

D.A. Smith (Cornell U.)

A multi-wavelength technique is used to study the origin and evolution of star-formation in a sample of twenty UGC radio-luminous starburst galaxies. Deep broad-band J (1.25 $\mu$m), H (1.65 $\mu$m) and K (2.2 $\mu$m) images of these galaxies and two ``normal'' comparison galaxies have been obtained with the IPAC/JPL Prime Focus Infrared Camera at the Palomar 5-meter telescope. Color maps constructed from these images provide an extinction estimate and assess the relative contributions of evolved red stars and thermal dust emission to the K band emission. Low-resolution K band spectra, acquired with the Cryogenic Spectrograph on the KPNO 2.1-meter, measure the strength of CO absorption features and determine whether red supergiants dominate the stellar component of the 2.2 $\mu$m emission. The spatial distribution of evolved stars mapped in the K band images is then compared to the recent star-formation traced in published radio maps. Together, the galaxy mass, supergiant population, and extinction corrected 2.2 $\mu$m luminosity constrain the star-formation history of the galaxy. Comparing star-formation properties as a function of interaction strength and age traces the evolution of starburst activity. An analysis of UGC8387, a luminous merging starburst system, is presented along with preliminary results from the near-infrared imaging and spectral observations of the sample.

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