학술논문
Galaxy Build-up in the first 1.5 Gyr of Cosmic History: Insights from the Stellar Mass Function at $z\sim4-9$ from JWST NIRCam Observations
Document Type
Working Paper
Author
Weibel, Andrea; Oesch, Pascal A.; Barrufet, Laia; Gottumukkala, Rashmi; Ellis, Richard S.; Santini, Paola; Weaver, John R.; Allen, Natalie; Bouwens, Rychard; Bowler, Rebecca A. A.; Brammer, Gabe; Carnall, Adam C.; Cullen, Fergus; Dayal, Pratika; Donnan, Callum T.; Dunlop, James S.; Giavalisco, Mauro; Grogin, Norman A.; Illingworth, Garth D.; Koekemoer, Anton M.; Labbe, Ivo; Marchesini, Danilo; McLeod, Derek J.; McLure, Ross J.; Naidu, Rohan P.; Shuntov, Marko; Stefanon, Mauro; Toft, Sune; Xiao, Mengyuan
Source
Subject
Language
Abstract
Combining the public JWST/NIRCam imaging programs CEERS, PRIMER and JADES, spanning a total area of $\sim$500 arcmin$^2$, we obtain a sample of $>$30,000 galaxies at $z\sim4-9$ that allows us to perform a complete, rest-optical selected census of the galaxy population at $z>3$. Comparing the stellar mass $M_*$ and the UV-slope $\beta$ distributions between JWST- and HST-selected samples, we generally find very good agreement and no significant biases. Nevertheless, JWST enables us to probe a small population of UV-red galaxies that was missing from previous HST-based LBG samples. We measure galaxy stellar mass functions (SMFs) at $z\sim4-9$ and show that they are broadly consistent with existing literature results. However, UV-red galaxies dominate the high-mass end of the SMF at least out to $z\sim6$. In particular the most massive galaxies typically show very red colors between $\lambda_{obs}\sim1.5\mu$m and $\sim4.5\mu$m, and thus JWST's unprecedented resolution and sensitivity at these wavelengths yields more accurate constraints on their abundance and masses. The implied redshift evolution of the high-mass end of the SMF suggests a rapid build-up of massive dust-obscured as well as quiescent galaxies from $z\sim6$ to $z\sim4$ as well as an enhanced efficiency of star formation towards earlier times ($z\gtrsim6$). We find the SMFs to be steep over the entire redshift range, and slightly steepening with redshift from $z\sim 4-6$, reaching values of $\approx-2$ at $z\gtrsim6$. Finally, we show that the galaxy mass density grows by a factor $\sim20\times$ in the $\sim1$ Gyr of cosmic time from $z\sim9$ to $z\sim4$. Our results emphasize the importance of rest-frame optically-selected samples in inferring accurate distributions of physical properties and studying the mass build-up of galaxies in the first 1.5 Gyr of cosmic history.
Comment: 29 pages, 17 figures, submitted to MNRAS
Comment: 29 pages, 17 figures, submitted to MNRAS