The Morphological Diversities among Star‐forming Galaxies at High Redshifts in the Great Observatories Origins Deep Survey
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We used the deep, multiwavelength images obtained by the Great Observatories Origins Deep Survey (GOODS) to identify ∼4700 Lyman break galaxies (LBGs) at z > 2.5, and 292 starburst galaxies at z ∼ 1.2. We present the results from morphological analysis based on light profile shape and ellipticity for ∼1333 of the most luminous LBGs. About 40% of LBGs at z ∼ 3 have exponential profiles, ∼30% of the galaxies have steep (r 1/4-like) profiles, and ∼30% of LBGs have multiple cores of disturbed morphologies suggestive of close pairs or mergers. The fraction of spheriod-like LBGs decrease by about 15% from z ∼ 5 to 3. A comparison of LBGs with the starburst galaxies at z ∼ 1.2 shows that disklike and merger morphologies are dominant, but the fraction of spheroid-like profiles is about 20% higher among LBGs. The ellipticity distribution for LBGs exhibits a pronounced skew toward high ellipticities (ε > 0.5), which cannot be explained by morphologies similar to the local disks and spheroids viewed at random orientations. The peak of the distribution evolves toward lower ε, from 0.7 at z = 4 to ∼0.5 at z = 3. The ellipticity distribution for the z ∼ 1.2 galaxies is relatively flat, similar to that seen for present-day galaxies. The dominance of elongated morphologies suggests that in a significant fraction of LBGs we may be witnessing star formation in clumps along gas-rich filaments, or the earliest gas-rich bars that encompass essentially the entire visible galaxy. © 2006. The American Astronomical Society. All rights reserved.
author list (cited authors)
Ravindranath, S., Giavalisco, M., Ferguson, H. C., Conselice, C., Katz, N., Weinberg, M., ... Papovich, C.