|Program Name||Starburst Galaxies in the UZC|
|Lisa Kewley [email] [web]|
|Co-Investigator(s)||Margaret Geller, Michael Kurtz
Understanding the star formation rate in the nearby universe is a crucial
anchor for understanding the star formation history of the universe. The
differences between samples of star forming galaxies selected on the basis
of large equivalent width (EW(H) and samples selected on the basis of
60 - 100 micron luminosity (IR hereafter) are one of many indications of
inadequacies in our observational and theoretical understanding.
Optically selected samples contain sets of extreme HII galaxies which are
essentially absent from IR-selected samples of starburst galaxies.
IR selected samples contain extreme dust-enshrouded
(hidden) starbursts which are absent from optically selected samples.
Cross-correlation of the UZC with the IRAS catalog yields 5679 sources. This trimester we propose to obtain FAST spectra for the 130 galaxies which have (i) EW(H < A 5; 000 km s1, and (iii) RAs between 10 and 15 hours. None of these galaxies have FAST spectra, nor do they have other spectra of sufficient quality to derive optical classifications, reliable Balmer decrements, or abundances. The lower limit on cz implies a typical slit covering fraction > 15%. For substantially elongated galaxies we plan to orient the slit along the major axis to maximize the slit covering fraction. To obtain metallicities and reliable Balmer decrements we require S/N ~ 25 at Ha. Our experience and the experience of Barton Gillespie at al. indicate that 10-20 minute exposures are adequate to achieve the required S/N. We also require several flux standards throughout each night. We therefore request 5 dark nights for this portion of the "outlier" sample.
To understand the role of tidal triggering in initiating the starbursts, we will require redshifts for the probable companion galaxies of our "outlier" sample. Most of these companion galaxies already have redshifts. We plan to measure the few missings ones as necessary.
|Spectra||[search in archive]|
|Trimester(s) data taken||2003b (proposed 2003a)|
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