Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Steven L. Finkelstein
Micaela B. Bagley
Henry C. Ferguson
Stephen M. Wilkins
Jeyhan S. Kartaltepe
Casey Papovich
L. Y. Aaron Yung
Pablo Arrabal Haro
Peter Behroozi
Mark Dickinson
Dale D. Kocevski
Anton M. Koekemoer
Rebecca L. Larson
Aurelien Le Bail
Alexa M. Morales
Pablo G. Perez-Gonzalez
Denis Burgarella
Romeel Dave
Michaela Hirschmann
Rachel S. Somerville
Abstract： We present an investigation into the first 500 Myr of galaxy evolution from the Cosmic Evolution Early Release Science (CEERS) survey. CEERS, one of 13 JWST ERS programs, targets galaxy formation from z~0.5 to z>10 using several imaging and spectroscopic modes. We make use of the first epoch of CEERS NIRCam imaging, spanning 35.5 sq. arcmin, to search for candidate galaxies at z>9. Following a detailed data reduction process implementing several custom steps to produce high-quality reduced images, we perform multi-band photometry across seven NIRCam broad and medium-band (and six Hubble broadband) filters focusing on robust colors and accurate total fluxes. We measure photometric redshifts and devise a robust set of selection criteria to identify a sample of 26 galaxy candidates at z~9-16. These objects are compact with a median half-light radius of ~0.5 kpc. We present an early estimate of the z~11 rest-frame ultraviolet (UV) luminosity function, finding that the number density of galaxies at M_UV ~ -20 appears to evolve very little from z~9 to z~11. We also find that the abundance (surface density [arcmin^-2]) of our candidates exceeds nearly all theoretical predictions. We explore potential implications, including that at z>10 star formation may be dominated by top-heavy initial mass functions, which would result in an increased ratio of UV light per unit halo mass, though a complete lack of dust attenuation and/or changing star-formation physics may also play a role. While spectroscopic confirmation of these sources is urgently required, our results suggest that the deeper views to come with JWST should yield prolific samples of ultra-high-redshift galaxies with which to further explore these conclusions.
Peer Review Status:
Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Jorge A. Zavala
Veronique Buat
Caitlin M. Casey
Denis Burgarella
Steven L. Finkelstein
Micaela B. Bagley
Laure Ciesla
Emanuele Daddi
Mark Dickinson
Henry C. Ferguson
Maximilien Franco
E. F. Jim'enez-Andrade
Jeyhan S. Kartaltepe
Anton M. Koekemoer
Aurélien Le Bail
E. J. Murphy
Casey Papovich
Sandro Tacchella
Stephen M. Wilkins
Itziar Aretxaga
Abstract： Lyman Break Galaxy (LBG) candidates at z>10 are rapidly being identified in JWST/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of rest-frame UV photons, these sources are expected to drop out in the bluer filters while being well detected in redder filters. However, here we show that dust-enshrouded star-forming galaxies at lower redshifts (z<7) may also mimic the near-infrared (near-IR) colors of z>10 LBGs, representing potential contaminants in LBG candidate samples. First, we analyze CEERS-DSFG-1, a NIRCam dropout undetected in the F115W and F150W filters but detected at longer wavelengths. Combining the JWST data with (sub)millimeter constraints, including deep NOEMA interferometric observations, we show that this source is a dusty star-forming galaxy (DSFG) at z~5.1. We also present a tentative 2.6sigma SCUBA-2 detection at 850um around a recently identified z~16 LBG candidate in the same field and show that, if the emission is real and associated with this candidate, the available photometry is consistent with a z~5 dusty galaxy with strong nebular emission lines despite its blue near-IR colors. Further observations on this candidate are imperative to mitigate the low confidence of this tentative submillimeter emission and its positional uncertainty. Our analysis shows that robust (sub)millimeter detections of NIRCam dropout galaxies likely imply z=4-6 redshift solutions, where the observed near-IR break would be the result of a strong rest-frame optical Balmer break combined with high dust attenuation and strong nebular line emission, rather than the rest-frame UV Lyman break. This provides evidence that DSFGs may contaminate searches for ultra high-redshift LBG candidates from JWST observations.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2023-02-19
Micaela B. Bagley
Nor Pirzkal
Steven L. Finkelstein
Casey Papovich
Danielle A. Berg
Jennifer M. Lotz
Gene C. K. Leung
Henry C. Ferguson
Anton M. Koekemoer
Mark Dickinson
Jeyhan S. Kartaltepe
Dale D. Kocevski
Rachel S. Somerville
L. Y. Aaron Yung
Bren E. Backhaus
Caitlin M. Casey
Marco Castellano
Óscar A. Chávez Ortiz
Katherine Chworowsky
Isabella G. Cox
Abstract： We present the Next Generation Deep Extragalactic Exploratory Public (NGDEEP)
Survey, a deep slitless spectroscopic and imaging Cycle 1 JWST treasury survey
designed to constrain feedback mechanisms in low-mass galaxies across cosmic
time. NGDEEP targets the Hubble Ultra Deep Field (HUDF) with NIRISS slitless
spectroscopy (f~1.2e-18 erg/s/cm^2, 5sigma) to measure metallicities and
star-formation rates (SFRs) for low-mass galaxies through the peak of the
cosmic SFR density (0.5
Peer Review Status:Awaiting Review
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