The Star Formation History of a Post-starburst Galaxy from SDSS Data Release 7

Type Conference Paper
Names Ryan Sanders, E. Hooper, M. Wolf, C. Tremonti
Proceedings Title Bulletin of the American Astronomical Society
Conference Name American Astronomical Society, AAS Meeting #219, #346.07
Volume 219
Date January 1, 2012
URL http://adsabs.harvard.edu/abs/2012AAS...21924607S
Library Catalog NASA ADS
Abstract We discuss studies on the E+A galaxy J0754+1648 from SDSS Data Release 7. The stages of galaxy mergers are well established, but the time scales of the transition between phases are not well understood. We look into the star formation history of this galaxy using deep optical spectra acquired on the WIYN 3.5-meter telescope at KPNO with the Sparsepak IFU on the bench spectrograph. The galaxy was chosen from a sample of E+A galaxies which show extended or variable radio emission indicating possible ongoing or recent AGN activity. The galaxy displays a highly disturbed morphology indicating a recent merger, as well as showing both poststarburst and starburst spectroscopic signatures in different regions. We estimate star formation rates using emission line flux measurements, providing a lower limit for the total star formation rate in the galaxy. We use the R23 ratio to roughly estimate metallicity. We fit simple stellar populations to the continuum using the Bruzual and Charlot 2003 models to estimate stellar population ages in different regions of the galaxy. We have 1.4 GHz radio data from FIRST which suggests the possibility of an AGN along with large amounts of [OIII] flux in fibers near the peak radio emission. The fibers showing a poststarburst spectroscopic signature also lie in the vicinity of the peak radio emission. We also see evidence of possible gas outflow in this region. The galaxy shows a large amount of ongoing star formation in regions farther removed from the possible AGN. Overall, the galaxy appears to be transitioning between the starburst and poststarburst phase. This work was supported by the National Science Foundation's REU program through NSF Award AST-1004881.
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