Optical Imaging and Spectroscopy of the Edge-On Sbc Galaxy UGC10043: Evidence for a Galactic Wind and a Peculiar Triaxial Bulge

Abstract

We present new optical imaging and spectroscopy of the peculiar, edge-on Sbc galaxy UGC10043. B & R imaging reveals that the inner bulge of UGC10043 is elongated perpendicular to the major axis. At larger r, the bulge isophotes twist to become oblate and nearly circular, suggesting the bulge is triaxial. Based on stellar and ionized gas kinematics, the bulge shows no clear evidence for rotation about either its major or minor axis. The southwestern quadrant of the bulge is girdled by a narrow dust lane parallel to the minor axis that may be part of an inner polar ring. The stellar disk of UGC10043 has a low optical surface brightness, a small scale height, a mild integral sign warp, and a dusty, inner region that appears tilted relative to the outlying disk. The HA and [NII] emission lines in UGC10043 resolve into multiple velocity components, indicating the presence of a large-scale galactic wind with an outflow velocity of ~104 km/s. HA+[NII] imaging reaffirms this picture by revealing ionized gas extended to |z|~3.5kpc in a biconical structure. The [NII]/HA line intensity ratio increases with increasing distance from the plane, reaching values as high as 1.7. Unlike most galaxies with large-scale winds, UGC10043 has only a modest global star formation rate (~1M_sun/yr), implying the wind is powered by a rather feeble central starburst. We discuss evolutionary scenarios that could account for both the structural complexities of UGC10043 and its large-scale wind. [Abridged]