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Session 49 - Starburst Galaxies.
Display session, Tuesday, January 16
North Banquet Hall, Convention Center
The nearby peculiar SAB(r)bc galaxy NGC3310 provides a superb opportunity to obtain a detailed understanding of a burst of massive star formation triggered by the accretion of a satellite object. With a global B-V color of +0.32, this galaxy is one of the bluest spiral galaxies in the RC3 catalog. The far--infrared luminosity of NGC3310 (L_fir=1.2\times10^10 L_ødot) indicates that the global starburst occurring in this galaxy is comparable in strength to that of the ``prototypical'' starburst galaxy M82. The presence of arcs and a jet--like feature, a displacement between the dynamical and stellar centers of mass, and low metallicities suggest that NGC3310 represents the final stages of a merger between a spiral and a dwarf galaxy, and perhaps has undergone a nuclear explosion. A detailed understanding of the star forming properties of NGC3310 will provide a unique foundation for studies of more distant objects.
We present the first far--ultraviolet (FUV, \lambda \sim 1500 Åimage of NGC3310. This \sim 3^\prime\prime FWHM resolution image was obtained by the Ultraviolet Imaging Telescope as part of the Astro--2 mission in March 1995. The FUV image shows a bright disk with a luminous nuclear ring of star formation. FUV emission also arises from several knots in a ``loop'' to the northwest of the galaxy and from the ``jet''; these regions are also sites of recent star formation. FUV luminosities of the knots in the nuclear ring are \sim 10 times higher than that of 30 Doradus; the emission from each of these regions is equivalent to that of 100 to 400 O stars in a region <200 pc in diameter. The luminosities and morphologies of the FUV emitting regions will be compared to those observed at H\alpha and other wavelengths in order to constrain the star formation properties of this unusual galaxy.
Program listing for Tuesday