Dusty starbursts masquerading as ultra-high redshift galaxies in jwst ceers observations
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
American Astronomical Society
Abstract
Lyman-break galaxy (LBG) candidates at z 10 are rapidly being identified in James Webb Space Telescope
(JWST)/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of restframe 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 2.6σ SCUBA-2 detection at 850 μm 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.
Description
Keywords
Astronomy, Physics, Cosmology, Galaxy photometry, High-redshift galaxies
Citation
Fontana, A. et al. (2023). Dusty starbursts masquerading as ultra-high redshift galaxies in jwst ceers observations. The Astrophysical Journal Letters, 943,L9. https://doi.org/10.3847/2041-8213/acacfe