1. Galaxy build-up in the first 1.5 Gyr of cosmic history: insights from the stellar mass function at z ~ 4–9 from JWST NIRCam observations.
- Author
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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, Dickinson, Mark, Donnan, Callum T, Dunlop, James S, Giavalisco, Mauro, Grogin, Norman A, and Illingworth, Garth D
- Subjects
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GALACTIC evolution , *STELLAR mass , *CENSUS , *PHYSICAL distribution of goods , *STAR formation - Abstract
Combining the public JWST /NIRCam imaging programs CEERS, PRIMER, and JADES, spanning a total area of |$\sim 500\, {\rm arcmin}^2$| , we obtain a sample of |$\gt $| 30 000 galaxies at |$z_{\rm phot}\sim 4\!-\!9$| that allows us to perform a complete, rest-optical-selected census of the galaxy population at |$z\gt 3$|. Comparing the stellar mass |$M_*$| and the UV-slope |$\beta$| distributions between JWST - and HST -selected samples, we generally find very good agreement and no significant biases. Nevertheless, JWST enables us to probe a new population of UV-red galaxies that was missing from previous HST -based Lyman-break galaxy (LBG) samples. We measure galaxy stellar mass functions (SMFs) at |$z\sim 4\!-\!9$| down to limiting masses of |$10^{7.5}\!-\!10^{8.5}\, {\rm M_\odot }$| , finding steep low-mass slopes over the entire redshift range, reaching values of |$\alpha \approx -2$| at |$z\gtrsim 6$|. At the high-mass end, UV-red galaxies dominate at least out to |$z\sim 6$|. The implied redshift evolution of the SMF suggests a rapid build-up of massive dust-obscured or quiescent galaxies from |$z\sim 6$| to |$z\sim 4$| as well as an enhanced efficiency of star formation towards earlier times (|$z\gtrsim 6$|). Finally, we show that the galaxy mass density grows by a factor |$\sim 20\times$| from |$z\sim 9$| to |$z\sim 4$|. 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. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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