Chain Galaxies in the Tadpole Advanced Camera for Surveys Field

Colors and magnitudes were determined for 69 chain galaxies, 58 other linearstructures, 32 normal edge-on galaxies, and all of their large star formationclumps in the HST ACS field of the Tadpole galaxy. Redshifts of 0.5 to 2 areinferred from comparisons with published color-evolution models. The lineargalaxies have no red nuclear bulges like the normal disk galaxies in our field,but the star formation clumps in each have about the same colors andmagnitudes. Light profiles along the linear galaxies tend to be flat, unlikethe exponential profiles of normal galaxies. Although the most extreme of thelinear objects look like beaded filaments, they are all probably edge-on disksthat will evolve to late Hubble type galaxies. The lack of an exponentialprofile is either the result of a dust scale height that is comparable to thestellar scale height, or an intrinsically irregular structure. Examples ofgalaxies that could be face-on versions of linear galaxies are shown. They havean irregular clumpy structure with no central bulge and with clump colors andmagnitudes that are comparable to those in the linears. Radiative transfersolutions to the magnitudes and surface brightnesses of inclined dusty galaxiessuggest that edge-on disks should become more prominent near the detectionlimit for surface brightness. The surface brightness distribution of theedge-on galaxies in this field confirm this selection effect. The starformation regions are much more massive than in modern galaxies, averaging upto 10^9 Msun for kpc scales.Comment: 15 pages, 9 figures, accepted for ApJ, 603, March 1, 200