AAS 205th Meeting, 9-13 January 2005
Session 60 Secular Evolution Potpourri: Star Formation to Galactic Structures
Poster, Tuesday, January 11, 2005, 9:20am-6:30pm, Exhibit Hall

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[60.22] Star Formation in the Center of the Advanced Merger NGC 4194

M. Hancock, D. Weistrop (UNLV), M. E. Kaiser (JHU)

We have obtained STIS longslit spectra of the central region of the advanced merger NGC 4194. The spectra cover the wavelength range 1150-1750 angstroms in the FUV and 2900-10270 angstroms in the visible. Results from the study of the properties of 14 star forming regions (knots) are presented. We determine the average E(B-V)=0.98 mag by comparing the Halpha+[N II] flux to the Hbeta flux. If the [N II] contribution is 40% then the average E(B-V)=0.50 mag. The presence of strong stellar winds, indicated by blue shifted FUV absorption lines, and the absence of emission lines lead us to believe that knot 6 is a bubble. The combined Halpha+[N II] luminosity of the 14 knots yield a total SFR of ~6 solar masses per year and the combined [O II] luminosity of those knots yield a total SFR of ~8 solar masses per year. Using Starburst99, and the EW(Halpha+[N II]) and EW(Hbeta), we estimate the ages of the star forming regions to be ~6-11 Myr. The sizes of the knots were determined from L(Hbeta) and range from ~7 pc to ~22 pc when a filling factor of 1 is assumed. The sizes are a factor of ~2.15 larger for a filling factor of 0.1.

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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.