Fraction of Clumpy Star-forming Galaxies at 0.5 ≤ z ≤ 3 in UVCANDELS: Dependence on Stellar Mass and Environment

Zahra Sattari, Bahram Mobasher, Nima Chartab, Daniel D. Kelson, Harry I. Teplitz, Marc Rafelski, Norman A. Grogin, Anton M. Koekemoer, Xin Wang, Rogier A. Windhorst, Anahita Alavi, Laura Prichard, Ben Sunnquist, Jonathan P. Gardner, Eric Gawiser, Nimish P. Hathi, Matthew J. Hayes, Zhiyuan Ji, Vihang Mehta, Brant E. RobertsonClaudia Scarlata, L. Y.Aaron Yung, Christopher J. Conselice, Y. Sophia Dai, Yicheng Guo, Ray A. Lucas, Alec Martin, Swara Ravindranath

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

High-resolution imaging of galaxies in rest-frame UV has revealed the existence of giant star-forming clumps prevalent in high-redshift galaxies. Studying these substructures provides important information about their formation and evolution and informs theoretical galaxy evolution models. We present a new method to identify clumps in galaxies’ high-resolution rest-frame UV images. Using imaging data from CANDELS and UVCANDELS, we identify star-forming clumps in an HST/F160W ≤ 25 AB mag sample of 6767 galaxies at 0.5 ≤ z ≤ 3 in four fields, GOODS-N, GOODS-S, EGS, and COSMOS. We use a low-passband filter in Fourier space to reconstruct the background image of a galaxy and detect small-scale features (clumps) on the background-subtracted image. Clumpy galaxies are defined as those having at least one off-center clump that contributes a minimum of 10% of the galaxy’s total rest-frame UV flux. We measure the fraction of clumpy galaxies (f clumpy) as a function of stellar mass, redshift, and galaxy environment. Our results indicate that f clumpy increases with redshift, reaching ∼65% at z ∼ 1.5. We also find that f clumpy in low-mass galaxies ( 9.5 ≤ log ( M * / M ⊙ ) ≤ 10 ) is 10% higher compared to that of their high-mass counterparts ( log ( M * / M ⊙ ) > 10.5 ). Moreover, we find no evidence of significant environmental dependence of f clumpy for galaxies at the redshift range of this study. Our results suggest that the fragmentation of gas clouds under violent disk instability remains the primary driving mechanism for clump formation, and incidents common in dense environments, such as mergers, are not the dominant processes.

Original languageEnglish (US)
Article number147
JournalAstrophysical Journal
Volume951
Issue number2
DOIs
StatePublished - Jul 1 2023
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.

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