TY - JOUR

T1 - A Long Time Ago in a Galaxy Far, Far Away

T2 - A Candidate z similar to 12 Galaxy in Early JWST CEERS Imaging

AU - Finkelstein, Steven L.

AU - Bagley, Micaela B.

AU - Haro, Pablo Arrabal

AU - Dickinson, Mark

AU - Ferguson, Henry C.

AU - Kartaltepe, Jeyhan S.

AU - Papovich, Casey

AU - Burgarella, Denis

AU - Kocevski, Dale D.

AU - Huertas-Company, Marc

AU - Iyer, Kartheik G.

AU - Koekemoer, Anton M.

AU - Larson, Rebecca L.

AU - Perez-Gonzalez, Pablo G.

AU - Rose, Caitlin

AU - Tacchella, Sandro

AU - Wilkins, Stephen M.

AU - Chworowsky, Katherine

AU - Medrano, Aubrey

AU - Morales, Alexa M.

AU - Somerville, Rachel S.

AU - Yung, L. Y. Aaron

AU - Fontana, Adriano

AU - Giavalisco, Mauro

AU - Grazian, Andrea

AU - Grogin, Norman A.

AU - Kewley, Lisa J.

AU - Kirkpatrick, Allison

AU - Kurczynski, Peter

AU - Lotz, Jennifer M.

AU - Pentericci, Laura

AU - Pirzkal, Nor

AU - Ravindranath, Swara

AU - Ryan, Russell E.

AU - Trump, Jonathan R.

AU - Yang, Guang

AU - Almaini, Omar

AU - Amorin, Ricardo O.

AU - Annunziatella, Marianna

AU - Backhaus, Bren E.

AU - Barro, Guillermo

AU - Behroozi, Peter

AU - Bell, Eric F.

AU - Bhatawdekar, Rachana

AU - Bisigello, Laura

AU - Bromm, Volker

AU - Fujimoto, Seiji

AU - Gomez-Guijarro, Carlos

AU - Hirschmann, Michaela

AU - Matharu, Jasleen

AU - CEERS Team

PY - 2022/12/1

Y1 - 2022/12/1

N2 - We report the discovery of a candidate galaxy with a photo -z of z similar to 12 in the first epoch of the James Webb Space Telescope (JWST) Cosmic Evolution Early Release Science Survey. Following conservative selection criteria, we identify a source with a robust zphot = 11.8(+0.3) (-0.2) (1 sigma uncertainty) with m(F200W) = 27.3 and > 7 sigma detections in five filters. The source is not detected at lambda < 1.4 mu m in deep imaging from both Hubble Space Telescope (HST) and JWST and has faint similar to 3 sigma detections in JWST F150W and HST F160W, which signal a Ly alpha break near the red edge of both filters, implying z similar to 12. This object (Maisie's Galaxy) exhibits F115W - F200W > 1.9 mag (2 sigma lower limit) with a blue continuum slope, resulting in 99.6% of the photo-z probability distribution function favoring z > 11. All data-quality images show no artifacts at the candidate's position, and independent analyses consistently find a strong preference for z > 11. Its colors are inconsistent with Galactic stars, and it is resolved (r(h) = 340 +/- 14 pc). Maisie's Galaxy has log M-*/M-?similar to 8.5 and is highly star-forming (log sSFR similar to -8.2 yr(-1)), with a blue rest-UV color (beta similar to -2.5) indicating little dust, though not extremely low metallicity. While the presence of this source is in tension with most predictions, it agrees with empirical extrapolations assuming UV luminosity functions that smoothly decline with increasing redshift. Should follow-up spectroscopy validate this redshift, our universe was already aglow with galaxies less than 400 Myr after the Big Bang.

AB - We report the discovery of a candidate galaxy with a photo -z of z similar to 12 in the first epoch of the James Webb Space Telescope (JWST) Cosmic Evolution Early Release Science Survey. Following conservative selection criteria, we identify a source with a robust zphot = 11.8(+0.3) (-0.2) (1 sigma uncertainty) with m(F200W) = 27.3 and > 7 sigma detections in five filters. The source is not detected at lambda < 1.4 mu m in deep imaging from both Hubble Space Telescope (HST) and JWST and has faint similar to 3 sigma detections in JWST F150W and HST F160W, which signal a Ly alpha break near the red edge of both filters, implying z similar to 12. This object (Maisie's Galaxy) exhibits F115W - F200W > 1.9 mag (2 sigma lower limit) with a blue continuum slope, resulting in 99.6% of the photo-z probability distribution function favoring z > 11. All data-quality images show no artifacts at the candidate's position, and independent analyses consistently find a strong preference for z > 11. Its colors are inconsistent with Galactic stars, and it is resolved (r(h) = 340 +/- 14 pc). Maisie's Galaxy has log M-*/M-?similar to 8.5 and is highly star-forming (log sSFR similar to -8.2 yr(-1)), with a blue rest-UV color (beta similar to -2.5) indicating little dust, though not extremely low metallicity. While the presence of this source is in tension with most predictions, it agrees with empirical extrapolations assuming UV luminosity functions that smoothly decline with increasing redshift. Should follow-up spectroscopy validate this redshift, our universe was already aglow with galaxies less than 400 Myr after the Big Bang.

KW - STAR-FORMATION HISTORIES

KW - EPOCH SIMULATIONS FLARES

KW - LUMINOSITY FUNCTION

KW - SEMIANALYTIC FORECASTS

KW - SPACE-TELESCOPE

KW - 1ST GALAXIES

KW - LIGHT-CONES

KW - L-DWARF

KW - STELLAR

KW - MASS

U2 - 10.3847/2041-8213/ac966e

DO - 10.3847/2041-8213/ac966e

M3 - Letter

VL - 940

JO - The Astrophysical Journal Letters

JF - The Astrophysical Journal Letters

SN - 2041-8205

IS - 2

M1 - 55

ER -