42 research outputs found
JADES: Using NIRCam Photometry to Investigate the Dependence of Stellar Mass Inferences on the IMF in the Early Universe
The detection of numerous and relatively bright galaxies at redshifts z > 9
has prompted new investigations into the star-forming properties of
high-redshift galaxies. Using local forms of the initial mass function (IMF) to
estimate stellar masses of these galaxies from their light output leads to
galaxy masses that are at the limit allowed for the state of the LambdaCDM
Universe at their redshift. We explore how varying the IMF assumed in studies
of galaxies in the early universe changes the inferred values for the stellar
masses of these galaxies. We infer galaxy properties with the SED fitting code
Prospector using varying IMF parameterizations for a sample of 102 galaxies
from the JWST Advanced Deep Extragalactic Survey (JADES) spectroscopically
confirmed to be at z > 6.7, with additional photometry from the JWST
Extragalactic Medium Band Survey (JEMS) for twenty-one galaxies. We demonstrate
that models with stellar masses reduced by a factor of three or more do not
affect the modeled spectral energy distribution (SED).Comment: The Significance statement is required for PNAS submissio
JADES: Resolving the Stellar Component and Filamentary Overdense Environment of Hubble Space Telescope (HST)-dark Submillimeter Galaxy HDF850.1 at z = 5.18
© 2024 The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/HDF850.1 is the brightest submillimeter galaxy (SMG) in the Hubble Deep Field. It is known as a heavily dust-obscured star-forming galaxy embedded in an overdense environment at z = 5.18. With nine-band NIRCam images at 0.8–5.0 μm obtained through the JWST Advanced Deep Extragalactic Survey, we detect and resolve the rest-frame UV–optical counterpart of HDF850.1, which splits into two components because of heavy dust obscuration in the center. The southern component leaks UV and Hα photons, bringing the galaxy ∼100 times above the empirical relation between infrared excess and UV continuum slope (IRX–β UV). The northern component is higher in dust attenuation and thus fainter in UV and Hα surface brightness. We construct a spatially resolved dust-attenuation map from the NIRCam images, well matched with the dust continuum emission obtained through millimeter interferometry. The whole system hosts a stellar mass of 1010.8±0.1 M ⊙ and star formation rate (SFR) of 102.8±0.2 M ⊙ yr−1, placing the galaxy at the massive end of the star-forming main sequence at this epoch. We further confirm that HDF850.1 resides in a complex overdense environment at z = 5.17–5.30, which hosts another luminous SMG at z = 5.30 (GN10). The filamentary structures of the overdensity are characterized by 109 Hα-emitting galaxies confirmed through NIRCam slitless spectroscopy at 3.9–5 μm, of which only eight were known before the JWST observations. Given the existence of a similar galaxy overdensity in the GOODS-S field, our results suggest that 50% ± 20% of the cosmic star formation at z = 5.1–5.5 occur in protocluster environments.Peer reviewe
JADES: Resolving the Stellar Component and Filamentary Overdense Environment of HST-Dark Submillimeter Galaxy HDF850.1 at
HDF850.1 is the brightest submillimeter galaxy (SMG) in the Hubble Deep
Field. It is known as a heavily dust-obscured star-forming galaxy embedded in
an overdense environment at . With nine-band NIRCam images at 0.8-5.0
m obtained through the JWST Advanced Deep Extragalactic Survey (JADES), we
detect and resolve the rest-frame UV-optical counterpart of HDF850.1, which
splits into two components because of heavy dust obscuration in the center. The
southern component leaks UV and H photons, bringing the galaxy
100 times above the empirical relation between infrared excess and UV
continuum slope (IRX-). The northern component is higher in
dust attenuation and thus fainter in UV and H surface brightness. We
construct a spatially resolved dust attenuation map from the NIRCam images,
well matched with the dust continuum emission obtained through millimeter
interferometry. The whole system hosts a stellar mass of
and star-formation rate of
, placing the galaxy at the
massive end of the star-forming main sequence at this epoch. We further confirm
that HDF850.1 resides in a complex overdense environment at ,
which hosts another luminous SMG at (GN10). The filamentary structures
of the overdensity are characterized by 109 H-emitting galaxies
confirmed through NIRCam slitless spectroscopy at 3.9-5 m, of which only
eight were known before the JWST observations. Given the existence of a similar
galaxy overdensity in the GOODS-S field, our results suggest that % of
the cosmic star formation at occur in protocluster environments.Comment: 44 pages, 16 figures, 2 tables. Resubmitted to ApJ after including
the first-round referee's comment
JADES + JEMS: A Detailed Look at the Buildup of Central Stellar Cores and Suppression of Star Formation in Galaxies at Redshifts 3 < z < 4.5
We present a spatially resolved study of stellar populations in 6 galaxies
with stellar masses at using 14-filter
JWST/NIRCam imaging from the JADES and JEMS surveys. The 6 galaxies are
visually selected to have clumpy substructures with distinct colors over
rest-frame \r{A}, including a bright dominant stellar core that is
close to their stellar-light centroids. With 23-filter photometry from HST to
JWST, we measure the stellar-population properties of individual structural
components via SED fitting using Prospector. We find that the central stellar
cores are times more massive than the Toomre mass, indicating they
may not form via in-situ fragmentation. The stellar cores have stellar ages of
Gyr that are similar to the timescale of clump inward migration due
to dynamical friction, suggesting that they likely instead formed through the
coalescence of giant stellar clumps. While they have not yet quenched, the 6
galaxies are below the star-forming main sequence by dex. Within each
galaxy, we find that the specific star formation rate is lower in the central
stellar core, and the stellar-mass surface density of the core is already
similar to quenched galaxies of the same masses and redshifts. Meanwhile, the
stellar ages of the cores are either comparable to or younger than the
extended, smooth parts of the galaxies. Our findings are consistent with model
predictions of the gas-rich compaction scenario for the buildup of galaxies'
central regions at high redshifts. We are likely witnessing the coeval
formation of dense central cores, along with the onset of galaxy-wide quenching
at .Comment: 32 pages, 16 figures, submitted to ApJ. Comments are welcom
The JWST Advanced Deep Extragalactic Survey: Discovery of an Extreme Galaxy Overdensity at with JWST/NIRCam in GOODS-S
We report the discovery of an extreme galaxy overdensity at in the
GOODS-S field using JWST/NIRCam imaging from JADES and JEMS alongside
JWST/NIRCam wide field slitless spectroscopy from FRESCO. We identified
potential members of the overdensity using HST+JWST photometry spanning
. These data provide accurate and
well-constrained photometric redshifts down to .
We subsequently confirmed galaxies at using JWST
slitless spectroscopy over through a
targeted line search for around the best-fit photometric
redshift. We verified that of these galaxies reside in the field while
galaxies reside in a density around times that of a random
volume. Stellar populations for these galaxies were inferred from the
photometry and used to construct the star-forming main sequence, where
protocluster members appeared more massive and exhibited earlier star formation
(and thus older stellar populations) when compared to their field galaxy
counterparts. We estimate the total halo mass of this large-scale structure to
be using an empirical stellar mass to halo mass relation, which is
likely an underestimate as a result of incompleteness. Our discovery
demonstrates the power of JWST at constraining dark matter halo assembly and
galaxy formation at very early cosmic times.Comment: Resubmitted to ApJ based on reviewer report; main text has 15 pages,
6 figures and 1 table; appendix has 1 page, 2 figure sets, and 2 table
The JWST Advanced Deep Extragalactic Survey: Discovery of an Extreme Galaxy Overdensity at z = 5.4 with JWST/NIRCam in GOODS-S
© 2024 The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/We report the discovery of an extreme galaxy overdensity at in the GOODS-S field using JWST/NIRCam imaging from JADES and JEMS alongside JWST/NIRCam wide field slitless spectroscopy from FRESCO. We identified potential members of the overdensity using HST+JWST photometry spanning . These data provide accurate and well-constrained photometric redshifts down to . We subsequently confirmed galaxies at using JWST slitless spectroscopy over through a targeted line search for around the best-fit photometric redshift. We verified that of these galaxies reside in the field while galaxies reside in a density around times that of a random volume. Stellar populations for these galaxies were inferred from the photometry and used to construct the star-forming main sequence, where protocluster members appeared more massive and exhibited earlier star formation (and thus older stellar populations) when compared to their field galaxy counterparts. We estimate the total halo mass of this large-scale structure to be using an empirical stellar mass to halo mass relation, which is likely an underestimate as a result of incompleteness. Our discovery demonstrates the power of JWST at constraining dark matter halo assembly and galaxy formation at very early cosmic times.Peer reviewe
Inside the bubble: exploring the environments of reionisation-era Lyman-α emitting galaxies with JADES and FRESCO⋆
© 2024 The Author(s). Published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/We present a study of the environments of 17 Lyman-α emitting galaxies (LAEs) in the reionisation-era (5.8 5%) observed in our sample of LAEs, suggesting the presence of ionised hydrogen along the line of sight towards at least eight out of 17 LAEs. We find minimum physical 'bubble'sizes of the order of R ion ∼ 0.1- 1pMpc are required in a patchy reionisation scenario where ionised bubbles containing the LAEs are embedded in a fully neutral IGM. Around half of the LAEs in our sample are found to coincide with large-scale galaxy overdensities seen in FRESCO at z ∼ 5.8- 5.9 and z ∼ 7.3, suggesting Lyman-α transmission is strongly enhanced in such overdense regions, and underlining the importance of LAEs as tracers of the first large-scale ionised bubbles. Considering only spectroscopically confirmed galaxies, we find our sample of UV-faint LAEs (M UV ≳ -20mag) and their direct neighbours are generally not able to produce the required ionised regions based on the Lyman-α transmission properties, suggesting lower-luminosity sources likely play an important role in carving out these bubbles. These observations demonstrate the combined power of JWST multi-object and slitless spectroscopy in acquiring a unique view of the early Universe during cosmic reionisation via the most distant LAEs.Peer reviewe
JADES: Insights into the low-mass end of the mass–metallicity–SFR relation at 3 < z < 10 from deep JWST/NIRSpec spectroscopy⋆
© 2024 The Author(s). Published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/We analysed the gas-phase metallicity properties of a sample of low-stellar-mass (log M⋆/M⊙ ≲ 9) galaxies at 3  6, with galaxies significantly less enriched than predicted given their M⋆ and SFR (with a median offset in log(O/H) of ∼0.5 dex, significant at ∼5σ). These observations are consistent with an enhanced stochasticity in the gas accretion and star-formation history of high-redshift systems, prompting us to reconsider the nature of the relationship between M⋆, O/H, and SFR in the early Universe.Peer reviewe
The Star-forming and Ionizing Properties of Dwarf z~6-9 Galaxies in JADES: Insights on Bursty Star Formation and Ionized Bubble Growth
Reionization is thought to be driven by faint star-forming galaxies, but
characterizing this population in detail has long remained very challenging.
Here we utilize deep nine-band NIRCam imaging from JADES to study the
star-forming and ionizing properties of 756 galaxies, including
hundreds of very UV-faint objects (). The faintest
() galaxies in our sample typically have stellar masses of
and young light-weighted ages (50
Myr), though some show strong Balmer breaks implying much older ages (500
Myr). We find no evidence for extremely massive galaxies (
) in our sample. We infer a strong (factor 2) decline in the
typical [OIII]H EWs towards very faint galaxies, yet a
weak UV luminosity dependence on the H EWs at . We demonstrate
that these EW trends can be explained if fainter galaxies have systematically
lower metallicities as well as more recently-declining star formation histories
relative to the most UV-luminous galaxies in our sample. Our data provide
evidence that the brightest galaxies are frequently experiencing a recent
strong upturn in SFR. We also discuss how the EW trends may be influenced by a
strong correlation between and Lyman continuum escape fraction.
This alternative explanation has dramatically different implications for the
contribution of galaxies along the luminosity function to cosmic reionization,
highlighting the need for deep spectroscopic follow-up. Finally, we quantify
the photometric overdensities around two strong Ly emitters in
the JADES footprint. One Ly emitter lies close to a strong photometric
overdensity while the other shows no significant nearby overdensity, perhaps
implying that not all strong Ly emitters reside in large ionized
bubbles.Comment: 29 pages, 16 figures. Submitted to MNRAS. Comments welcom
The galaxies missed by Hubble and ALMA: the contribution of extremely red galaxies to the cosmic census at 3<z<8
Using deep JWST imaging from JADES, JEMS and SMILES, we characterize
optically-faint and extremely red galaxies at that were previously
missing from galaxy census estimates. The data indicate the existence of
abundant, dusty and post-starburst-like galaxies down to M, below
the sensitivity limit of Spitzer and ALMA. Modeling the NIRCam and HST
photometry of these red sources can result in extreme, high values for both
stellar mass and star formation rate (SFR); however, including 7 MIRI filters
out to 21m results in decreased mass (median 0.6 dex for
logM/M10), and SFR (median 10 for SFR100
M/yr). At , our sample includes a high fraction of little red
dots (LRDs; NIRCam-selected dust-reddened AGN candidates). We significantly
measure older stellar populations in the LRDs out to rest-frame 3m (the
stellar bump) and rule out a dominant contribution from hot dust emission, a
signature of AGN contamination to stellar population measurements. This allows
us to measure their contribution to the cosmic census at , below the
typical detection limits of ALMA (). We find that
these sources, which are overwhelmingly missed by HST and ALMA, could
effectively double the obscured fraction of the star formation rate density at
compared to some estimates, showing that prior to JWST, the obscured
contribution from fainter sources could be underestimated. Finally, we identify
five sources with evidence for Balmer breaks and high stellar masses at
. While spectroscopy is required to determine their nature, we
discuss possible measurement systematics to explore with future data.Comment: submitted to AAS Journals, comments welcome