3 research outputs found
Chain Galaxies in the Tadpole ACS Field
Colors and magnitudes were determined for 69 chain galaxies, 58 other linear
structures, 32 normal edge-on galaxies, and all of their large star formation
clumps in the HST ACS field of the Tadpole galaxy. Redshifts of 0.5 to 2 are
inferred from comparisons with published color-evolution models. The linear
galaxies 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 and
magnitudes. Light profiles along the linear galaxies tend to be flat, unlike
the exponential profiles of normal galaxies. Although the most extreme of the
linear objects look like beaded filaments, they are all probably edge-on disks
that will evolve to late Hubble type galaxies. The lack of an exponential
profile is either the result of a dust scale height that is comparable to the
stellar scale height, or an intrinsically irregular structure. Examples of
galaxies that could be face-on versions of linear galaxies are shown. They have
an irregular clumpy structure with no central bulge and with clump colors and
magnitudes that are comparable to those in the linears. Radiative transfer
solutions to the magnitudes and surface brightnesses of inclined dusty galaxies
suggest that edge-on disks should become more prominent near the detection
limit for surface brightness. The surface brightness distribution of the
edge-on galaxies in this field confirm this selection effect. The star
formation regions are much more massive than in modern galaxies, averaging up
to 10^9 Msun for kpc scales.Comment: 15 pages, 9 figures, accepted for ApJ, 603, March 1, 200