UV-bright Star-forming Clumps and Their Host Galaxies in UVCANDELS at 0.5 ≤ z ≤ 1

October 2023 • 2023ApJ...955..106M

Authors • Martin, Alec • Guo, Yicheng • Wang, Xin • Koekemoer, Anton M. • Rafelski, Marc • Teplitz, Harry I. • Windhorst, Rogier A. • Alavi, Anahita • Grogin, Norman A. • Prichard, Laura • Sunnquist, Ben • Ceverino, Daniel • Chartab, Nima • Conselice, Christopher J. • Dai, Y. Sophia • Dekel, Avishai • Gardner, Jonathan P. • Gawiser, Eric • Hathi, Nimish P. • Hayes, Matthew J. • Jansen, Rolf A. • Ji, Zhiyuan • Koo, David C. • Lucas, Ray A. • Mandelker, Nir • Mehta, Vihang • Mobasher, Bahram • Nedkova, Kalina V. • Primack, Joel • Ravindranath, Swara • Robertson, Brant E. • Rutkowski, Michael J. • Sattari, Zahra • Soto, Emmaris • Yung, L. Y. Aaron

Abstract • Giant star-forming clumps are a prominent feature of star-forming galaxies (SFGs) and contain important clues on galaxy formation and evolution. However, the basic demographics of clumps and their host galaxies remain uncertain. Using the Hubble Space Telescope/Wide Field Camera 3 F275W images from the Ultraviolet Imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, we detect and analyze giant star-forming clumps in galaxies at 0.5 ≤ z ≤ 1, connecting two epochs when clumps are common (at cosmic high noon, z ~ 2) and rare (in the local Universe). We construct a clump sample whose rest-frame 1600 Å luminosity is 3 times higher than the most luminous local H II regions (M _UV ≤ -16 AB). In our sample, 35% ± 3% of low-mass galaxies (log[M _∗/M _⊙] < 10) are clumpy (i.e., containing at least one off-center clump). This fraction changes to 22% ± 3% and 22% ± 4% for intermediate (10 ≤ log[M _∗/M _⊙] ≤ 10.5) and high-mass (log[M _∗/M _⊙] > 10.5) galaxies, in agreement with previous studies. When compared to similar-mass nonclumpy SFGs, low- and intermediate-mass clumpy SFGs tend to have higher star formation rates (SFRs) and bluer rest-frame U - V colors, while high-mass clumpy SFGs tend to be larger than nonclumpy SFGs. However, clumpy and nonclumpy SFGs have similar Sérsic index, indicating a similar underlying density profile. Furthermore, we investigate how the UV luminosity of star-forming regions correlates with the physical properties of host galaxies. On average, more luminous star-forming regions reside in more luminous, smaller, and/or higher specific SFR galaxies and are found closer to their hosts' galactic centers.

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Anahita Alavi

Assistant Scientist

Harry Teplitz

Senior Scientist