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Session 76 - Star Formation in Galaxies.
Display session, Friday, January 09
The optical structure of the luminous blue galaxy NGC 7673 (Mrk 325) is analyzed based on new images obtained with WFPC2 and the WIYN Telescope. This galaxy resembles moderate-to-high redshift blue galaxies in having strong [OII] emission, blue colors, and high surface brightness. The WFPC2 F555W and F814W data show this "clumpy irregular" galaxy is a distorted spiral with a dusty nuclear region and a myriad of bright stellar clusters, many of which are embedded in HII regions observed in our WIYN images. Of particular interest is the giant HII complex in the NE corner of the galaxy. This symmetrical H-alpha feature has a (V-I) color of about 0.3, and separates into several smaller clusters in the WFPC2 images. A lower limit for the H\alpha flux from this "blue blob" is about 5\times10^40 erg s^-1 cm^-2 . The outer structure of NGC 7673 in our WIYN images also shows an arc-like feature similar to that seen in the luminous blue galaxy NGC 3310. This is probably a remnant of a past interaction and we suggest that the unusual state of NGC 7673 is the result of a "soft merger" with a small system.
This work is part of the WFPC2 Investigation Definition Team program which is supported by NASA Contract NAS7-1260 to JPL. The WIYN Observatory is a joint facility of the University of Wisconsin - Madison, Indiana University, Yale University, and the National Optical Astronomy Observatories.
Program listing for Friday