Identification and properties of intense star-forming galaxies at redshifts z > 10

Abstract

Surveys with James Webb Space Telescope (JWST) have discovered candidate galaxies in the first 400 Myr of cosmic time 1-5 . The properties of these distant galaxies provide initial conditions for understanding early galaxy formation and cosmic reionisation 6 . Preliminary indications have suggested these candidate galaxies may be more massive and abundant than previously thought 1,7-9 . However, without spectroscopic confirmation of their distances to constrain their intrinsic brightnesses, their inferred properties remain uncertain. Here we report on four galaxies located in the JWST Advanced Deep Extragalactic Survey (JADES) Near-Infrared Camera (NIRCam) imaging with photometric redshifts 𝒛 ∼ 𝟏𝟎 − 𝟏𝟑 subsequently confirmed by JADES JWST Near-Infrared Spectrograph (NIRSpec) observations 10 . These galaxies include the first redshift 𝒛 > 𝟏𝟐 systems both discovered and spectroscopically confirmed by JWST. Using stellar population modelling, we find the galaxies typically contain a hundred million solar masses in stars, in stellar populations that are less than one hundred million years old. The moderate star formation rates and compact sizes suggest elevated star formation rate surface densities, a key indicator of their formation pathways. Taken together, these measurements show that the first galaxies contributing to cosmic reionisation formed rapidly and with intense internal radiation fields.

CEERS Spectroscopic Confirmation of NIRCam-selected z ≳ 8 Galaxy Candidates with JWST/NIRSpec: Initial Characterization of Their Properties

“…This sets the benchmark for the spectroscopic confirmation of large samples of galaxies, further allowing detailed investigations into the UV luminosity function shape at z  8.5 and the characterization of the highredshift Lyman-break galaxy (LBG) population newly identified with JWST. This work is complementary to the recent successful spectroscopic confirmation of the higher redshift, but much (1-2 mag) fainter galaxies at z = 9.51-13.20 in lensing cluster fields (Roberts-Borsani et al 2022;Williams et al 2023) or very deep observations of the Hubble Ultra Deep Field (Curtis-Lake et al 2023; Robertson et al 2023).…”

“…Another reason might be the difficulty of determining the redshift at z  9.5 due to the lack of strong emission lines in the NIRSpec wavelength coverage. Then, while the true redshifts are distributed on both sides of the peak of P(z) according to uncertainties in the broadband photometry, the spec-z confirmation may be biased to z  9.5 when the sensitivity is not deep enough to capture the Lyα break (Curtis-Lake et al 2023;Roberts-Borsani et al 2022;Robertson et al 2023) and has to rely on the line identification to determine z spec . The absence of the NIRCam-based dropout filter may also at least partially contribute to the >1σ difference between z phot and z spec for these sources.…”

CEERS Key Paper. V. Galaxies at 4 < z < 9 Are Bluer than They Appear–Characterizing Galaxy Stellar Populations from Rest-frame ∼1 μm Imaging

“…Future studies will be able to combine both NIRCam and MIRI imaging, providing JWST-quality data from 0.8 to 10 μm, with NIRSPec spectroscopy, which will improve the constraints presented here. Already there are indications, using JWST/NIRCam data only, that the number density of luminous galaxies at z > 10 may be much higher than predictions (e.g., Finkelstein et al 2022b;Bouwens et al 2023;Donnan et al 2023;Harikane et al 2023;Naidu et al 2022;Robertson et al 2023). One interpretation of these discoveries is that the UV luminosity per unit of stellar mass (the UV "efficiency") may be higher than models predict.…”

“…The ionization from these sources is needed to explain observations that the hydrogenneutral fraction of the intergalactic medium (IGM) was 50% by z ∼ 8 (Planck Collaboration et al 2020). 33 Indeed, early observations from JWST have already identified candidates for galaxies at z  15 (Finkelstein et al 2022b;Curtis-Lake et al 2023;Donnan et al 2023;Robertson et al 2023). Spectroscopy from JWST of galaxies at z ∼ 8-9 shows emission lines from heavy elements that appear to require metallicities of ≈5%-10% Z e (Arellano-Córdova et al 2022;Fujimoto et al 2022;Heintz et al 2023;Langeroodi et al 2022;Matthee et al 2022;Schaerer et al 2022;Trump et al 2023;Curti et al 2023;Katz et al 2023), implying these galaxies have experienced at least one (and probably multiple) generation(s) of previous stars.…”

Discovery of a quiescent galaxy at z=7.3

“…Finally, the mosaics were created using the stage 3 of the pipeline. For further details on the JADES photometry data reduction pipeline we refer to Robertson et al 2022 [83] and Tacchella et al 2023 [84].…”