Extensive Lensing Survey of Optical and Near-infrared Dark Objects (El Sonido): HST H-faint Galaxies behind 101 Lensing Clusters

Sun, Fengwu; Egami, Eiichi; Pérez-González, Pablo G.; Smail, Ian; Caputi, Karina I.; Bauer, Franz E.; Rawle, Timothy D.; Fujimoto, Seiji; Kohno, Kotaro; Dudzevičiūtė, Ugnė; Atek, Hakim; Bianconi, Matteo; Chapman, Scott C.; Combes, Francoise; Jauzac, Mathilde; Jolly, Jean-Baptiste; Koekemoer, Anton M.; Magdis, Georgios E.; Rodighiero, Giulia; Rujopakarn, Wiphu; Schaerer, Daniel; Steinhardt, Charles L.; Van der Werf, Paul; Walth, Gregory L.; Weaver, John R.

Abstract

We present a Spitzer/IRAC survey of H-faint (H160 ≳ 26.4, < 5σ) sources in 101 lensing cluster fields. Across a CANDELS/Wide-like survey area of ∼648 arcmin2 (effectively ∼221 arcmin2 in the source plane), we have securely discovered 53 sources in the IRAC Channel-2 band (CH2, 4.5 μm; median CH2 = 22.46 ± 0.11 AB mag) that lack robust HST/WFC3-IR F160W counterparts. The most remarkable source in our sample, namely ES-009 in the field of Abell 2813, is the brightest H-faint galaxy at 4.5 μm known so far (CH2 = 20.48 ± 0.03 AB mag). We show that the H-faint sources in our sample are massive (median Mstar = 1010.3±0.3 M⊙), star-forming (median star formation rate $={100}_{-40}^{+60}$ M⊙ yr−1), and dust-obscured (AV = 2.6 ± 0.3) galaxies around a median photometric redshift of z = 3.9 ± 0.4. The stellar continua of 14 H-faint galaxies can be resolved in the CH2 band, suggesting a median circularized effective radius (Re,circ; lensing corrected) of 1.9 ± 0.2 kpc and <1.5 kpc for the resolved and whole samples, respectively. This is consistent with the sizes of massive unobscured galaxies at z ∼ 4, indicating that H-faint galaxies represent the dusty tail of the distribution of a wider galaxy population. Comparing with the ALMA dust continuum sizes of similar galaxies reported previously, we conclude that the heavy dust obscuration in H-faint galaxies is related to the compactness of both stellar and dust continua (Re,circ ∼ 1 kpc). These H-faint galaxies make up ${16}_{-7}^{+13}$% of the galaxies in the stellar-mass range of 1010 − 1011.2 M⊙ at z = 3 ∼ 5, contributing to ${8}_{-4}^{+8}$% of the cosmic star formation rate density in this epoch and likely tracing the early phase of massive galaxy formation

Citation

Sun, F., Egami, E., Pérez-González, P. G., Smail, I., Caputi, K. I., Bauer, F. E., …Weaver, J. R. (2021). Extensive Lensing Survey of Optical and Near-infrared Dark Objects (El Sonido): HST H-faint Galaxies behind 101 Lensing Clusters. Astrophysical Journal, 922(2), https://doi.org/10.3847/1538-4357/ac2578

• Journal Article Type: Article
• Acceptance Date: Sep 8, 2021
• Online Publication Date: Nov 25, 2021
• Publication Date: 2021-12
• Deposit Date: Dec 21, 2021
• Publicly Available Date: Dec 21, 2021
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 922
• Issue: 2
• DOI: https://doi.org/10.3847/1538-4357/ac2578
• Public URL: https://durham-repository.worktribe.com/output/1218292