TY - JOUR

T1 - UV luminosity density results at z > 8 from the first JWST/NIRCam fields

T2 - limitations of early data sets and the need for spectroscopy

AU - Bouwens, Rychard

AU - Illingworth, Garth

AU - Oesch, Pascal

AU - Stefanon, Mauro

AU - Naidu, Rohan

AU - Van Leeuwen, Ivana

AU - Magee, Dan

N1 - Publisher Copyright: © 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.

PY - 2023/7/1

Y1 - 2023/7/1

N2 - We have derived luminosity functions and set constraints on the UV luminosity and SFR density from z ∼17 to z ∼8, using the three most-studied JWST/NIRCam data sets, the SMACS0723, GLASS Parallel, and CEERS fields. We first used our own selections on two independent reductions of these data sets using the latest calibrations. A total of 18 z ∼8, 12 z ∼10, 5 z ∼13, and 1 z ∼17 candidate galaxies are identified over these fields in our primary reductions, with a similar number of candidates in our secondary reductions. We then use these two reductions, applying a quantitative discriminator, to segregate the full set of z ≥ 8 candidates reported over these fields from the literature, into three different samples, 'robust', 'solid', and 'possible'. Using all of these samples, we then derive UV LF and luminosity density results at z ≥ 8, finding substantial differences. For example, including the full set of 'solid' and 'possible' z ≥ 12 candidates from the literature, we find UV luminosity densities, which are ∼7× and ∼20× higher than relying on the 'robust' candidates alone. These results indicate the evolution of the UV LF and luminosity densities at z ≥ 8 is still extremely uncertain, emphasizing the need for spectroscopy and deeper NIRCam + optical imaging to obtain reliable results. Nevertheless, even with the very conservative 'robust' approach to selections, both from our own and those of other studies, we find the luminosity density from luminous (MUV < -19) galaxies to be ∼2 × larger than is easily achievable using constant star formation efficiency models, similar to what other early JWST results have suggested.

AB - We have derived luminosity functions and set constraints on the UV luminosity and SFR density from z ∼17 to z ∼8, using the three most-studied JWST/NIRCam data sets, the SMACS0723, GLASS Parallel, and CEERS fields. We first used our own selections on two independent reductions of these data sets using the latest calibrations. A total of 18 z ∼8, 12 z ∼10, 5 z ∼13, and 1 z ∼17 candidate galaxies are identified over these fields in our primary reductions, with a similar number of candidates in our secondary reductions. We then use these two reductions, applying a quantitative discriminator, to segregate the full set of z ≥ 8 candidates reported over these fields from the literature, into three different samples, 'robust', 'solid', and 'possible'. Using all of these samples, we then derive UV LF and luminosity density results at z ≥ 8, finding substantial differences. For example, including the full set of 'solid' and 'possible' z ≥ 12 candidates from the literature, we find UV luminosity densities, which are ∼7× and ∼20× higher than relying on the 'robust' candidates alone. These results indicate the evolution of the UV LF and luminosity densities at z ≥ 8 is still extremely uncertain, emphasizing the need for spectroscopy and deeper NIRCam + optical imaging to obtain reliable results. Nevertheless, even with the very conservative 'robust' approach to selections, both from our own and those of other studies, we find the luminosity density from luminous (MUV < -19) galaxies to be ∼2 × larger than is easily achievable using constant star formation efficiency models, similar to what other early JWST results have suggested.

KW - dark ages, reionization, first stars

KW - galaxies: evolution

KW - galaxies: high-redshift

U2 - 10.1093/mnras/stad1014

DO - 10.1093/mnras/stad1014

M3 - Journal article

AN - SCOPUS:85161288534

VL - 523

SP - 1009

EP - 1035

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

SN - 0035-8711

IS - 1

ER -