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Paper: Evolution and Internal Kinematics of Faint Blue Galaxies
Volume: 156, Highly Redshifted Radio Lines
Page: 113
Authors: Guhathakurta, P.; Ing, K.
Abstract: This paper describes two projects in progress aimed at improving our understanding of the evolution of distant field galaxies through a study of their linewidth-vs-luminosity relation. The first project relies on high dispersion spectroscopy using AAT/AUTOFIB of 100 faint blue galaxies at <{z}> = 0.25. Galaxy disks must be modeled in detail to statistically correct the observed ensemble of spatially averaged linewidths and to thereby derive a mean rotation speed for the sample: vcirc = 66 kms^{-1}. This is significantly smaller than the characteristic circular speed of local galaxies of comparable absolute magnitude (M_B = -19) and color (B-R = 1), 105kms^{-1}, indicating about 1 > ! - > ! 1.5 mag of luminosity evolution in the B band. The second project investigates the nature of faint galaxy internal dynamics with the help of spatially resolved Fabry-Perot datacubes of a subset of about 20 galaxies in the redshift range z = 0.3 - 0.45. The primary cause of line broadening appears to be overall disk rotation. Each galaxy is modeled on the basis of surface photometry derived from high angular resolution HST/WFPC2 and Keck/NIRC near infrared images to obtain a reliable estimate of its circular speed.
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