ABSTRACT
We present a measurement of average histograms of line-of-sight velocities over pairs of galaxies and galaxy clusters. Since the histogram can be measured at different galaxy-cluster ...separations, this observable is commonly referred to as the stacked phase-space density. We formulate the stacked phase-space density based on a halo-model approach so that the model can be applied to real samples of galaxies and clusters. We examine our model by using an actual sample of massive clusters with known weak-lensing masses and spectroscopic observations of galaxies around the clusters. A likelihood analysis with our model enables us to infer the spherical-symmetric velocity dispersion of observed galaxies in massive clusters. We find the velocity dispersion of galaxies surrounding clusters with their lensing masses of $1.1\times 10^{15}\, h^{-1}\,{\rm M}_{\odot }$ to be $1180^{+83}_{-70}\, \mathrm{km\,s^{-1}}$ at the 68 per cent confidence level. Our constraint confirms that the relation between the galaxy velocity dispersion and the host cluster mass in our sample is consistent with the prediction in dark-matter-only N-body simulations under General Relativity. Assuming that the Poisson equation in clusters can be altered by an effective gravitational constant of Geff, our measurement of the velocity dispersion can place a tight constraint of $0.88 \lt G_\mathrm{eff}/G_\mathrm{N} \lt 1.29\, (68{{\ \rm per\ cent}})$ at length-scales of a few Mpc about 2.5 Giga years ago, where GN is the Newton’s constant.
The far-infrared fine-structure line C ii at 1900.5 GHz is known to be one of the brightest cooling lines in local galaxies, and therefore it has been suggested to be an efficient tracer for star ...formation in very high redshift galaxies. However, recent results for galaxies at z > 6 have yielded numerous non-detections in star-forming galaxies, except for quasars and submillimetre galaxies. We report the results of ALMA observations of two lensed, star-forming galaxies at z = 6.029 and z = 6.703. The galaxy A383-5.1 (star formation rate SFR of 3.2 M⊙ yr−1 and magnification of μ = 11.4 ± 1.9) shows a line detection with $L_{\rm C\,\small {II}} = 8.9\times 10^{6}$ L⊙, making it the lowest $L_{\rm C\,\small {II}}$ detection at z > 6. For MS0451-H (SFR = 0.4 M⊙ yr−1 and μ = 100 ± 20) we provide an upper limit of $L_{\rm C\,\small {II}} < 3\times 10^{5}$ L⊙, which is 1 dex below the local SFR–$L_{\rm C\,\small {II}}$ relations. The results are consistent with predictions for low-metallicity galaxies at z > 6; however, other effects could also play a role in terms of decreasing LCII. The detection of A383-5.1 is encouraging and suggests that detections are possible, but much fainter than initially predicted.
Extending over three Hubble Space Telescope (HST) cycles, the Hubble Frontier Fields (HFF) initiative constitutes the largest commitment ever of HST time to the exploration of the distant Universe ...via gravitational lensing by massive galaxy clusters. Here, we present models of the mass distribution in the six HFF cluster lenses, derived from a joint strong- and weak-lensing analysis anchored by a total of 88 multiple-image systems identified in existing HST data. The resulting maps of the projected mass distribution and of the gravitational magnification effectively calibrate the HFF clusters as gravitational telescopes. Allowing the computation of search areas in the source plane, these maps are provided to the community to facilitate the exploitation of forthcoming HFF data for quantitative studies of the gravitationally lensed population of background galaxies. Our models of the gravitational magnification afforded by the HFF clusters allow us to quantify the lensing-induced boost in sensitivity over blank-field observations and predict that galaxies at z > 10 and as faint as m(AB) = 32 will be detectable, up to 2 mag fainter than the limit of the Hubble Ultra Deep Field.
Abstract
We present JWST NIRCam nine-band near-infrared imaging of the luminous
z
= 10.6 galaxy GN-z11 from the JWST Advanced Deep Extragalactic Survey of the GOODS-N field. We find a spectral energy ...distribution (SED) entirely consistent with the expected form of a high-redshift galaxy: a clear blue continuum from 1.5 to 4
μ
m with a complete dropout in F115W. The core of GN-z11 is extremely compact in JWST imaging. We analyze the image with a two-component model, using a point source and a Sérsic profile that fits to a half-light radius of 200 pc and an index
n
= 0.9. We find a low-surface-brightness haze about 0.″4 to the northeast of the galaxy, which is most likely a foreground object but might be a more extended component of GN-z11. At a spectroscopic redshift of 10.60 (Bunker et al. 2023), the comparison of the NIRCam F410M and F444W images spans the Balmer jump. From population-synthesis modeling, here assuming no light from an active galactic nucleus, we reproduce the SED of GN-z11, finding a stellar mass of ∼10
9
M
⊙
, a star formation rate of ∼20
M
⊙
yr
−1
, and a young stellar age of ∼20 Myr. Since massive galaxies at high redshift are likely to be highly clustered, we search for faint neighbors of GN-z11, finding nine galaxies out to ∼5 comoving Mpc transverse with photometric redshifts consistent with
z
= 10.6, and a tenth more tentative dropout only 3″ away. This is consistent with GN-z11 being hosted by a massive dark-matter halo (≈8 × 10
10
M
⊙
), though lower halo masses cannot be ruled out.
Abstract
We present JWST Extragalactic Medium-band Survey, the first public medium-band imaging survey carried out using JWST/NIRCam and NIRISS. These observations use ∼2 and ∼4
μ
m medium-band ...filters (NIRCam F182M, F210M, F430M, F460M, F480M; and NIRISS F430M and F480M in parallel) over 15.6 arcmin
2
in the Hubble Ultra Deep Field (UDF), thereby building on the deepest multiwavelength public data sets available anywhere on the sky. We describe our science goals, survey design, NIRCam and NIRISS image reduction methods, and describe our first data release of the science-ready mosaics, which reach 5
σ
point-source limits (AB mag) of ∼29.3–29.4 in 2
μ
m filters and ∼28.2–28.7 at 4
μ
m. Our chosen filters create a JWST imaging survey in the UDF that enables novel analysis of a range of spectral features potentially across the redshift range of 0.3 <
z
< 20, including Paschen-
α
, H
α
+N
ii
, and O
iii
+H
β
emission at high spatial resolution. We find that our JWST medium-band imaging efficiently identifies strong line emitters (medium-band colors >1 mag) across redshifts 1.5 <
z
< 9.3, most prominently H
α
+N
ii
and O
iii
+H
β
. We present our first data release including science-ready mosaics of each medium-band image available to the community, adding to the legacy value of past and future surveys in the UDF. This survey demonstrates the power of medium-band imaging with JWST, informing future extragalactic survey strategies using JWST observations.
We report 14 and 26 protocluster candidates at z = 5.7 and 6.6 over 14 and 16 deg2 areas, respectively, selected from 2230 (259) Ly emitters (LAEs) photometrically (spectroscopically) identified ...using Subaru/Hyper Suprime-Cam (HSC) deep images (Keck, Subaru, and Magellan spectra, and literature data). Six out of the 40 protocluster candidates include one to 13 spectroscopically confirmed LAEs. We conduct Monte Carlo simulations to estimate how many protocluster candidates are found by chance for randomly distributed sources, and find that the effective number of protocluster candidates at z = 5.7 (6.6) is six (five). By comparing with the cosmological Ly radiative transfer (RT) model reproducing the LAEs with reionization effects, we find that more than half of these protocluster candidates are progenitors of present-day clusters with mass of . We then investigate the correlation between the LAE overdensity δ and the Ly rest-frame equivalent width , because the cosmological Ly RT model suggests that the slope of the -δ relation steepens toward the epoch of cosmic reionization (EoR), due to the existence of ionized bubbles around galaxy overdensities easing the escape of Ly emission from the partly neutral intergalactic medium. The available HSC data suggest that the slope of the -δ correlation does not evolve from the post-reionization epoch, z = 5.7, to the EoR, z = 6.6, beyond the moderately large statistical errors. There is a possibility that we could detect the evolution of the -δ relation from z = 5.7 to 7.3 using the upcoming HSC observations that will provide large samples of LAEs at z = 6.6-7.3.
Abstract
We present a catalog of 717 candidate galaxies at
z
> 8 selected from 125 square arcmin of NIRCam imaging as part of the JWST Advanced Deep Extragalactic Survey (JADES). We combine the full ...JADES imaging data set with data from the JWST Extragalactic Medium Survey and First Reionization Epoch Spectroscopic COmplete Survey (FRESCO) along with extremely deep existing observations from Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) for a final filter set that includes 15 JWST/NIRCam filters and five HST/ACS filters. The high-redshift galaxy candidates were selected from their estimated photometric redshifts calculated using a template-fitting approach, followed by visual inspection from seven independent reviewers. We explore these candidates in detail, highlighting interesting resolved or extended sources, sources with very red long-wavelength slopes, and our highest-redshift candidates, which extend to
z
phot
∼ 18. Over 93% of the sources are newly identified from our deep JADES imaging, including 31 new galaxy candidates at
z
phot
> 12. We also investigate potential contamination by stellar objects, and do not find strong evidence from spectral energy distribution fitting that these faint high-redshift galaxy candidates are low-mass stars. Using 42 sources in our sample with measured spectroscopic redshifts from NIRSpec and FRESCO, we find excellent agreement to our photometric redshift estimates, with no catastrophic outliers and an average difference of 〈Δ
z
=
z
phot
−
z
spec
〉 = 0.26. These sources comprise one of the most robust samples for probing the early buildup of galaxies within the first few hundred million years of the Universe’s history.
Abstract
We present a study of the mass–metallicity relation (MZR) of 51 dwarf galaxies (
M
⋆
≈ 10
6.5
–10
9.5
M
⊙
) at
z
= 2–3 from the A2744 and SMACS J0723-3732 galaxy cluster fields. These dwarf ...galaxies are identified and confirmed by deep JWST/NIRISS imaging and slitless grism spectroscopic observations. By taking advantage of the superior performance of JWST and the gravitational lensing effect, we extend the previous MZR relation at
z
= 2–3 to a much lower-mass regime down by ≈2.5 orders of magnitude as compared with previous studies. We find that the MZR has a shallower slope at the low-mass end (
M
⋆
< 10
9
M
⊙
), with a slope turnover point of ≈10
9
M
⊙
. This implies that the dominating feedback processes in dwarf galaxies may be different from that in massive galaxies. From
z
= 3, to
z
= 2, the metallicity of the dwarf galaxies is enhanced by ≈0.09 dex for a given stellar mass, consistent with the mild evolution found in galaxies with higher mass. Furthermore, we confirm the existence of a fundamental metallicity relation (FMR) between the gas-phase metallicity, stellar mass, and star formation rate in dwarf galaxies at
z
= 2–3. Our derived FMR, which has no significant redshift evolution, can be used as a benchmark to understand the origin of the anticorrelation between the star formation rate and metallicity of dwarf galaxies in the high-
z
Universe.
Abstract
The dramatic first images with JWST demonstrated its power to provide unprecedented spatial detail for galaxies in the high-redshift universe. Here, we leverage the resolution and depth of ...the JWST Cosmic Evolution Early Release Science Survey data in the Extended Groth Strip to perform pixel-level morphological classifications of galaxies in JWST F150W imaging using the Morpheus deep-learning framework for astronomical image analysis. By cross-referencing with existing photometric redshift catalogs from the Hubble Space Telescope (HST) CANDELS survey, we show that JWST images indicate the emergence of disk morphologies before
z
∼ 2 and with candidates appearing as early as
z
∼ 5. By modeling the light profile of each object and accounting for the JWST point-spread function, we find the high-redshift disk candidates have exponential surface brightness profiles with an average Sérsic index 〈
n
〉 = 1.04 and >90% displaying “disky” profiles (
n
< 2). Comparing with prior Morpheus classifications in CANDELS we find that a plurality of JWST disk galaxy candidates were previously classified as
compact
based on the shallower HST imagery, indicating that the improved optical quality and depth of the JWST helps to reveal disk morphologies that were hiding in the noise. We discuss the implications of these early disk candidates on theories for cosmological disk galaxy formation.
Abstract
Spiral arms serve crucial purposes in star formation and galaxy evolution. In this paper, we report the identification of “A2744-DSG-
z
3,” a dusty, multiarm spiral galaxy at
z
= 3.059 using ...the James Webb Space Telescope (JWST) NIRISS imaging and grism spectroscopy. A2744-DSG-z3 was discovered as a gravitationally lensed submillimeter galaxy with the Atacama Large Millimeter/submillimeter Array (ALMA). This is the most distant stellar spiral structure seen thus far, consistent with cosmological simulations that suggest
z
≈ 3 as the epoch when spirals emerge. Thanks to the gravitational lensing and excellent spatial resolution of JWST, the spiral arms are resolved with a spatial resolution of ≈290 pc. Based on spectral energy distribution fitting, the spiral galaxy has a delensed star formation rate of 85 ± 30
M
⊙
yr
−1
, and a stellar mass of ≈10
10.6
M
⊙
, indicating that A2744-DSG-
z
3 is a main-sequence galaxy. After fitting the spiral arms, we find a stellar effective radius (
R
e,star
) of 5.0 ± 1.5 kpc. Combining with ALMA measurements, we find that the effective radii ratio between dust and stars is ≈0.4, similar to those of massive star‐forming galaxies (SFGs) at
z
∼ 2, indicating a compact dusty core in A2744-DSG-z3. Moreover, this galaxy appears to be living in a group environment: including A2744-DSG-z3, at least three galaxies at
z
= 3.05–3.06 are spectroscopically confirmed by JWST/NIRISS and ALMA, residing within a lensing-corrected projected scale of ≈70 kpc. This, along with the asymmetric brightness profile, further suggests that the spiral arms may be triggered by minor-merger events at
z
≳ 3.
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![[C ii] emission in z ∼ 6 st...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1745-3925_1745-3933/small "[C ii] emission in z ∼ 6 strongly lensed, star-forming galaxies")
