학술논문
Clumpy Galaxies in CANDELS. I. The Definition of UV Clumps and the Fraction of Clumpy Galaxies at 0.5
Astrophysics - Astrophysics of Galaxies
Document Type
Working Paper
Author
Guo, Yicheng; Ferguson, Henry C.; Bell, Eric F.; Koo, David C.; Conselice, Christopher J.; Giavalisco, Mauro; Kassin, Susan; Lu, Yu; Lucas, Ray; Mandelker, Nir; McIntosh, Daniel M.; Primack, Joel R.; Ravindranath, Swara; Barro, Guillermo; Ceverino, Daniel; Dekel, Avishai; Faber, Sandra M.; Fang, Jerome J.; Koekemoer, Anton M.; Noeske, Kai; Rafelski, Marc; Straughn, Amber
Source
ApJ 800 (2015) 39-60
Subject
Language
Abstract
Although giant clumps of stars are crucial to galaxy formation and evolution, the most basic demographics of clumps are still uncertain, mainly because the definition of clumps has not been thoroughly discussed. In this paper, we study the basic demographics of clumps in star-forming galaxies (SFGs) at 0.50.5. The redshift evolution of Fclumpy changes with the stellar mass (M*) of the galaxies. Low-mass (log(M*/Msun)<9.8) galaxies keep an almost constant Fclumpy of about 60% from z~3.0 to z~0.5. Intermediate-mass and massive galaxies drop their Fclumpy from 55% at z~3.0 to 40% and 15%, respectively, at z~0.5. We find that (1) the trend of disk stabilization predicted by violent disk instability matches the Fclumpy trend of massive galaxies; (2) minor mergers are a viable explanation of the Fclumpy trend of intermediate-mass galaxies at z<1.5, given a realistic observability timescale; and (3) major mergers are unlikely responsible for the Fclumpy trend in all masses at z<1.5. The clump contribution to the rest-frame UV light of SFGs shows a broad peak around galaxies with log(M*/Msun)~10.5 at all redshifts, possibly linked to the molecular gas fraction of the galaxies. (Abridged)
Comment: 22 pages, 15 figures. Appeared in ApJ (2015, 800, 39). A few typos corrected
Comment: 22 pages, 15 figures. Appeared in ApJ (2015, 800, 39). A few typos corrected