ORCID Profile
0000-0003-2680-005X
Current Organisations
Københavns Universitet
,
IT University of Copenhagen
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Sensory Processes, Perception and Performance | Psychology | Behavioural Ecology |
Expanding Knowledge in the Biological Sciences | Expanding Knowledge in Psychology and Cognitive Sciences | Expanding Knowledge in Technology
Publisher: American Astronomical Society
Date: 12-2022
Abstract: Wide Field Slitless Spectroscopy (WFSS) provides a powerful tool for detecting strong line emission in star-forming galaxies (SFGs) without the need for target preselection. As part of the GLASS-JWST Early Release Science (ERS) program, we leverage the near-infrared wavelength capabilities of NIRISS (1–2.2 μ m) to observe rest-optical emission lines out to z ∼ 3.4, to a depth and with a spatial resolution higher than ever before (H α to z 2.4 [O iii ]+H β to z 3.4). In this Letter we constrain the rest-frame [O III ] λ 5007 equivalent width (EW) distribution for a s le of 76 1 z 3.4 SFGs in the A2744 Hubble Frontier Field and determine an abundance fraction of extreme emission line galaxies with EW 750Å in our s le to be 12%. We determine a strong correlation between the measured H β and [O III ] λ 5007 EWs, supporting that the high [O III ] λ 5007 EW objects require massive stars in young stellar populations to generate the high-energy photons needed to doubly ionize oxygen. We extracted spectra for objects up to 2 mag fainter in the near-infrared than previous WFSS studies with the Hubble Space Telescope. Thus, this work clearly highlights the potential of JWST/NIRISS to provide high-quality WFSS data sets in crowded cluster environments.
Publisher: American Astronomical Society
Date: 07-2023
Abstract: The abundance of carbon relative to oxygen (C/O) is a promising probe of star formation history in the early universe, as the ratio changes with time due to production of these elements by different nucleosynthesis pathways. We present a measurement of log ( C / O ) = − 1.01 ± 0.12 (stat) ±0.15 (sys) in a z = 6.23 galaxy observed as part of the GLASS–JWST Early Release Science Program. Notably, we achieve good precision thanks to the detection of the rest-frame ultraviolet O iii ], C iii ], and C iv emission lines delivered by JWST/NIRSpec. The C/O abundance is ∼0.8 dex lower than the solar value and is consistent with the expected yield from core-collapse supernovae, indicating that longer-lived intermediate-mass stars have not fully contributed to carbon enrichment. This in turn implies rapid buildup of a young stellar population with age ≲100 Myr in a galaxy seen ∼900 Myr after the big bang. Our chemical abundance analysis is consistent with spectral energy distribution modeling of JWST/NIRCam photometric data, which indicates a current stellar mass log M * / M ☉ = 8.4 − 0.2 + 0.4 and specific star formation rate ≃20 Gyr −1 . These results showcase the value of chemical abundances and C/O in particular to study the earliest stages of galaxy assembly.
Publisher: American Astronomical Society
Date: 23-05-2023
Abstract: We select and characterize a s le of massive (log( M * / M ⊙ ) 10.6) quiescent galaxies (QGs) at 3 z 5 in the latest Cosmological Evolution Survey catalog (COSMOS2020). QGs are selected using a new rest-frame color-selection method, based on their probability of belonging to the quiescent group defined by a Gaussian mixture model (GMM) trained on rest-frame colors ( NUV − U , U − V , V − J ) of similarly massive galaxies at 2 z 3. We calculate the quiescent probability threshold above which a galaxy is classified as quiescent using simulated galaxies from the shark semi-analytical model. We find that, at z ≥ 3 in shark , the GMM/ NUVU − VJ method outperforms classical rest-frame UVJ selection and is a viable alternative. We select galaxies as quiescent based on their probability in COSMOS2020 at 3 z 5, and compare the selected s le to both UVJ - and NUVrJ -selected s les. We find that, although the new selection matches UVJ and NUVrJ in number, the overlap between color selections is only ∼50%–80%, implying that rest-frame color commonly used at lower-redshift selections cannot be equivalently used at z 3. We compute median rest-frame spectral energy distributions for our s le and find the median QG at 3 z 5 has a strong Balmer/4000 Å break, and residual NUV flux indicating recent quenching. We find the number densities of the entire quiescent population (including post-starbursts) more than doubles from 3.5 ± 2.2 × 10 −6 Mpc −3 at 4 z 5 to 1.4 ± 0.4 × 10 −5 Mpc −3 at 3 z 4, confirming that the onset of massive galaxy quenching occurs as early as 3 z 5.
Publisher: American Astronomical Society
Date: 27-12-2019
Publisher: American Astronomical Society
Date: 12-05-2017
Publisher: American Astronomical Society
Date: 02-2023
Abstract: The study of galaxy evolution hinges on our ability to interpret multiwavelength galaxy observations in terms of their physical properties. To do this, we rely on spectral energy distribution (SED) models, which allow us to infer physical parameters from spectrophotometric data. In recent years, thanks to wide and deep multiwave band galaxy surveys, the volume of high-quality data have significantly increased. Alongside the increased data, algorithms performing SED fitting have improved, including better modeling prescriptions, newer templates, and more extensive s ling in wavelength space. We present a comprehensive analysis of different SED-fitting codes including their methods and output with the aim of measuring the uncertainties caused by the modeling assumptions. We apply 14 of the most commonly used SED-fitting codes on s les from the CANDELS photometric catalogs at z ∼ 1 and z ∼ 3. We find agreement on the stellar mass, while we observe some discrepancies in the star formation rate (SFR) and dust-attenuation results. To explore the differences and biases among the codes, we explore the impact of the various modeling assumptions as they are set in the codes (e.g., star formation histories, nebular, dust and active galactic nucleus models) on the derived stellar masses, SFRs, and A V values. We then assess the difference among the codes on the SFR–stellar mass relation and we measure the contribution to the uncertainties by the modeling choices (i.e., the modeling uncertainties) in stellar mass (∼0.1 dex), SFR (∼0.3 dex), and dust attenuation (∼0.3 mag). Finally, we present some resources summarizing best practices in SED fitting.
Publisher: American Astronomical Society
Date: 08-2022
Abstract: The GLASS-JWST Early Release Science (hereafter GLASS-JWST-ERS) Program will obtain and make publicly available the deepest extragalactic data of the ERS c aign. It is primarily designed to address two key science questions, namely, “what sources ionized the universe and when?” and “how do baryons cycle through galaxies?”, while also enabling a broad variety of first look scientific investigations. In primary mode, it will obtain NIRISS and NIRSpec spectroscopy of galaxies lensed by the foreground Hubble Frontier Field cluster, Abell 2744. In parallel, it will use NIRCam to observe two fields that are offset from the cluster center, where lensing magnification is negligible, and which can thus be effectively considered blank fields. In order to prepare the community for access to this unprecedented data, we describe the scientific rationale, the survey design (including target selection and observational setups), and present pre-commissioning estimates of the expected sensitivity. In addition, we describe the planned public releases of high-level data products, for use by the wider astronomical community.
Publisher: American Astronomical Society
Date: 04-2023
Abstract: We present the spectroscopic confirmation of a protocluster at z = 7.88 behind the galaxy cluster Abell 2744 (hereafter A2744-z7p9OD). Using JWST NIRSpec, we find seven galaxies within a projected radius of 60 kpc. Although the galaxies reside in an overdensity around ≳20× greater than a random volume, they do not show strong Ly α emission. We place 2 σ upper limits on the rest-frame equivalent width –28 Å. Based on the tight upper limits to the Ly α emission, we constrain the volume-averaged neutral fraction of hydrogen in the intergalactic medium to be x HI 0.45 (68% C i ). Using an empirical M UV – M halo relation for in idual galaxies, we estimate that the total halo mass of the system is ≳4 × 10 11 M ⊙ . Likewise, the line-of-sight velocity dispersion is estimated to be 1100 ± 200 km s −1 . Using an empirical relation, we estimate the present-day halo mass of A2744-z7p9OD to be ∼2 × 10 15 M ⊙ , comparable to the Coma cluster. A2744-z7p9OD is the highest redshift spectroscopically confirmed protocluster to date, demonstrating the power of JWST to investigate the connection between dark-matter halo assembly and galaxy formation at very early times with medium-deep observations at hr total exposure time. Follow-up spectroscopy of the remaining photometric candidates of the overdensity will further refine the features of this system and help characterize the role of such overdensities in cosmic reionization.
Publisher: American Astronomical Society
Date: 25-08-2016
Publisher: American Astronomical Society
Date: 26-06-2014
Publisher: American Astronomical Society
Date: 03-04-2017
Publisher: American Astronomical Society
Date: 28-11-2019
Publisher: American Astronomical Society
Date: 24-01-2017
Publisher: American Astronomical Society
Date: 12-03-2018
Publisher: American Astronomical Society
Date: 12-2022
Abstract: We investigate the blue and optical rest-frame sizes ( λ ≃ 2300–4000 Å) of three compact star-forming regions in a galaxy at z = 4 strongly lensed (×30, ×45, and ×100) by the Hubble Frontier Field galaxy cluster A2744 using GLASS-ERS James Webb Space Telescope (JWST)/NIRISS imaging at 1.15 μ m, 1.50 μ m, and 2.0 μ m with a point-spread function ≲0.″1. In particular, the Balmer break is probed in detail for all multiply imaged sources of the system. With ages of a few tens of Myr, stellar masses in the range (0.7–4.0) ×10 6 M ⊙ and optical/ultraviolet effective radii spanning the interval 3 R eff 20 pc, such objects are currently the highest-redshift (spectroscopically confirmed) gravitationally bound young massive star clusters (YMCs), with stellar mass surface densities resembling those of local globular clusters. Optical (4000 Å, JWST-based) and ultraviolet (1600 Å, Hubble Space Telescope–based) sizes are fully compatible. The contribution to the ultraviolet underlying continuum emission (1600 Å) is ∼30%, which decreases by a factor of 2 in the optical for two of the YMCs (∼4000 Å rest-frame), reflecting the young ages ( Myr) inferred from the spectral energy distribution fitting and supported by the presence of high-ionization lines secured with the Very Large Telescope/MUSE. Such bursty forming regions enhance the specific star formation rate of the galaxy, which is ≃10 Gyr −1 . This galaxy would be among the extreme analogs observed in the local universe having a high star formation rate surface density and a high occurrence of massive stellar clusters in formation.
Publisher: American Astronomical Society
Date: 04-09-2019
Publisher: American Astronomical Society
Date: 04-2023
Abstract: We present a first look at the reddest 2–5 μ m sources found in deep images from the GLASS Early Release Science program. We undertake a general search, i.e., not looking for any particular spectral signatures, for sources detected only in bands redder than is reachable with the Hubble Space Telescope, and which would likely not have been identified in pre-JWST surveys. We search for sources down to AB ∼27 (corresponding to σ detection threshold) in any of the F200W to F444W filters, with a magnitude excess relative to F090W to F150W bands. Fainter than F444W we find 56 such sources of which 37 have reasonably constrained spectral energy distributions to which we can fit photometric redshifts. We find the majority of this population (∼65%) as 2 z 6 star-forming low-attenuation galaxies that are faint at rest-frame ultraviolet-optical wavelengths, have stellar masses 10 8.5 –10 9.5 M ⊙ , and have observed fluxes at μ m boosted by a combination of the Balmer break and emission lines. The typical implied rest equivalent widths are ∼200 Å with some extreme objects up to ∼1000 Å. This is in contrast with brighter magnitudes where the red sources tend to be z 3 quiescent galaxies and dusty star-forming objects. Our general selection criteria for red sources allow us to independently identify other phenomena as erse as extremely low-mass (∼10 8 M ⊙ ) quiescent galaxies at z 1, recovering recently identified z 11 galaxies and a very cool brown dwarf.
Publisher: American Astronomical Society
Date: 10-2022
Abstract: We present the first search for z ≥ 7, continuum-confirmed Lyman break sources with NIRISS/WFS spectroscopy over the Abell 2744 Frontier Fields cluster, as part of the GLASS-JWST-ERS survey. With ∼15 hr of preimaging and multiangle grism exposures in the F115W, F150W, and F200W filters, we describe the general data handling (i.e., reduction, cleaning, modeling, and extraction processes) and analysis for the GLASS-JWST survey. We showcase the power of JWST to peer deep into reionization, when most intergalactic hydrogen is neutral, by confirming two galaxies at z = 8.04 ± 0.15 and z = 7.90 ± 0.13 by means of their Lyman breaks. Fainter continuum spectra are observed in both the F150W and F200W bands, indicative of blue (−1.69 and −1.33) UV slopes and moderately bright absolute magnitudes (−20.37 and −19.68 mag). We do not detect strong Ly α in either galaxy, but do observe tentative (∼2.7–3.8 σ ) He ii λ 1640 Å, O iii ] λλ 1661,1666 Å, and N iii ] λλ 1747,1749 Å line emission in one, suggestive of low-metallicity, star-forming systems with possible nonthermal contributions. These novel observations provide a first look at the extraordinary potential of JWST/NIRISS for confirming representative s les of bright z ≥ 7 sources in the absence of strong emission lines, and gain unprecedented insight into their contributions toward cosmic reionization.
Publisher: American Astronomical Society
Date: 07-2023
Abstract: We present a new high-precision, JWST-based, strong-lensing model for the galaxy cluster Abell 2744 at z = 0.3072. By combining the deep, high-resolution JWST imaging from the Grism Lens Amplified Survey from Space–JWST and Ultradeep NIRSpec and NIRCam Observations before the Epoch of Reionization programs and a Director’s Discretionary Time program, with newly obtained Very Large Telescope/Multi Unit Spectroscopic Explorer (MUSE) data, we identify 32 multiple images from 11 background sources lensed by two external subclusters at distances of ∼160″ from the main cluster. The new MUSE observations enable the first spectroscopic confirmation of a multiple-image system in the external clumps. Moreover, the reanalysis of the spectrophotometric archival and JWST data yields 27 additional multiple images in the main cluster. The new lens model is constrained by 149 multiple images (∼66% more than in our previous model) covering an extended redshift range between 1.03 and 9.76. The subhalo mass component of the cluster includes 177 member galaxies down to m F160W = 21, of which 163 are spectroscopically confirmed. Internal velocity dispersions are measured for 85 members. The new lens model is characterized by a remarkably low scatter between the predicted and observed positions of the multiple images (0.″43). This precision is unprecedented given the large multiple-image s le, the complexity of the cluster mass distribution, and the large modeled area. The improved precision and resolution of the cluster total mass distribution provides a robust magnification map over a ∼30 arcmin 2 area, which is critical for inferring the intrinsic physical properties of the highly magnified, high- z sources. The lens model and the new MUSE redshift catalog are released with this publication.
Publisher: American Astronomical Society
Date: 02-2021
Abstract: For the extremely bright lensed galaxy SDSS J1723+3411 at z = 1.3293, we analyze spatially integrated MMT, Keck, and Hubble Space Telescope spectra that fully cover the rest-frame wavelength range of 1400–7200 Å. We also analyze near-IR spectra from Gemini that cover H α for a portion of the lensed arc. We report fluxes for 42 detected emission lines, and upper limits for an additional 22. This galaxy has extreme emission-line ratios and high equivalent widths that are characteristic of extreme emission-line galaxies. We compute strong emission-line diagnostics from both the rest-frame optical and rest-frame ultraviolet (UV), to constrain physical conditions and test the spectral diagnostics themselves. We tightly determine the nebular physical conditions using the most reliable diagnostics, and then compare to results from other diagnostics. We find disappointing performance from the UV-only diagnostics: they either are unable to measure the metallicity or dramatically underestimate it they overestimate the pressure and the UV diagnostic of ionization parameter has a strong metallicity dependence in this regime. Based on these results, we suggest that upcoming James Webb Space Telescope (JWST) spectroscopic surveys of galaxies in the reionization epoch should invest the additional integration time to capture the optical [O ii ] and [O iii ] emission lines, and not rely solely on the rest-frame UV emission lines. We make available the spectra they represent one of the highest-quality emission-line spectral atlases of star-forming galaxies available beyond the local universe, and will aid the planning of observations with JWST.
Publisher: Oxford University Press (OUP)
Date: 29-07-2023
Abstract: We present the results of a search for high-redshift (z & 9) galaxy candidates in the JWST UNCOVER survey, using deep NIRCam and NIRISS imaging in seven bands over ∼45 arcmin2 and ancillary Hubble Space Telescope (HST) observations. The NIRCam observations reach a 5σ limiting magnitude of ∼29.2 AB. The identification of high-z candidates relies on a combination of a dropout selection and photometric redshifts. We find 16 candidates at 9 & z & 12 and three candidates at 12 & z & 13, eight candidates are deemed very robust. Their lensing lification ranges from μ = 1.2 to 11.5. Candidates have a wide range of (lensing corrected) luminosities and young ages, with low stellar masses [6.8 & log(M⋆/M⊙) & 9.5] and low star formation rates (SFR = 0.2–7 M⊙ yr−1), confirming previous findings in early JWST observations of z & 9. A few galaxies at z ∼ 9−10 appear to show a clear Balmer break between the F356W and F444W/F410M bands, which helps constrain their stellar mass. We estimate blue UV continuum slopes between β = −1.8 and −2.3, typical for early galaxies at z & 9 but not as extreme as the bluest recently discovered sources. We also find evidence for a rapid redshift-evolution of the mass-luminosity relation and a redshift evolution of the UV continuum slope for a given range of intrinsic magnitude, in line with theoretical predictions. These findings suggest that deeper JWST observations are needed to reach the fainter galaxy population at those early epochs, and follow-up spectroscopy will help better constrain the physical properties and star formation histories of a larger s le of galaxies.
Publisher: American Astronomical Society
Date: 02-2016
Publisher: American Astronomical Society
Date: 03-04-2020
Publisher: American Astronomical Society
Date: 09-2023
Publisher: American Astronomical Society
Date: 25-07-2023
Abstract: Recent JWST/NIRCam imaging taken for the ultra-deep UNCOVER program reveals a very red dropout object at z phot ≃ 7.6, triply imaged by the galaxy cluster A2744 ( z d = 0.308). All three images are very compact, i.e., unresolved, with a delensed size upper limit of r e ≲ 35 pc. The images have apparent magnitudes of m F444W ∼ 25−26 AB, and the magnification-corrected absolute UV magnitude of the source is M UV,1450 = −16.81 ± 0.09. From the sum of observed fluxes and from a spectral energy distribution (SED) analysis, we obtain estimates of the bolometric luminosities of the source of L bol ≳ 10 43 erg s −1 and L bol ∼ 10 44 –10 46 erg s −1 , respectively. Based on its compact, point-like appearance, its position in color–color space, and the SED analysis, we tentatively conclude that this object is a UV-faint dust-obscured quasar-like object, i.e., an active galactic nucleus at high redshift. We also discuss other alternative origins for the object’s emission features, including a massive star cluster, Population III, supermassive, or dark stars, or a direct-collapse black hole. Although populations of red galaxies at similar photometric redshifts have been detected with JWST, this object is unique in that its high-redshift nature is corroborated geometrically by lensing, that it is unresolved despite being magnified—and thus intrinsically even more compact—and that it occupies notably distinct regions in both size–luminosity and color–color space. Planned UNCOVER JWST/NIRSpec observations, scheduled in Cycle 1, will enable a more detailed analysis of this object.
Publisher: American Astronomical Society
Date: 16-12-2016
Publisher: American Astronomical Society
Date: 29-06-2018
Publisher: American Astronomical Society
Date: 08-2016
Publisher: American Astronomical Society
Date: 20-07-2017
Publisher: American Astronomical Society
Date: 05-2023
Abstract: We report the detection of a high density of redshift z ≈ 10 galaxies behind the foreground cluster A2744, selected from imaging data obtained recently with NIRCam on board JWST by three programs—GLASS-JWST, UNCOVER, and DDT#2756. To ensure robust estimates of the lensing magnification μ , we use an improved version of our model that exploits the first epoch of NIRCam images and newly obtained MUSE spectra and avoids regions with μ 5 where the uncertainty may be higher. We detect seven bright z ≈ 10 galaxies with demagnified rest frame −22 ≲ M UV ≲ −19 mag, over an area of ∼37 arcmin 2 . Taking into account photometric incompleteness and the effects of lensing on luminosity and cosmological volume, we find that the density of z ≈ 10 galaxies in the field is about 10× (3×) larger than the average at M UV ≈ −21 ( −20) mag reported so far. The density is even higher when considering only the GLASS-JWST data, which are the deepest and the least affected by magnification and incompleteness. The GLASS-JWST field contains five out of seven galaxies, distributed along an apparent filamentary structure of 2 Mpc in projected length, and includes a close pair of candidates with M UV −20 mag having a projected separation of only 16 kpc. These findings suggest the presence of a z ≈ 10 overdensity in the field. In addition to providing excellent targets for efficient spectroscopic follow-up observations, our study confirms the high density of bright galaxies observed in early JWST observations but calls for multiple surveys along independent lines of sight to achieve an unbiased estimate of their average density and a first estimate of their clustering.
Publisher: American Astronomical Society
Date: 21-07-2014
Publisher: American Astronomical Society
Date: 30-11-2015
Publisher: EDP Sciences
Date: 04-2023
DOI: 10.1051/0004-6361/202245532
Abstract: Aims. The demographics of the production and escape of ionizing photons from UV-faint early galaxies is a key unknown that has hindered attempts to discover the primary drivers of reionization. With the advent of JWST, it is finally possible to observe the rest-frame optical nebular emission from in idual sub- L * z 3 galaxies to measure the production rate of ionizing photons, ξ ion . Methods. Here we study a s le of 370 z ∼ 3 − 7 galaxies spanning −23 M UV −15.5 (median M UV ≈ −18) with deep multiband HST and JWST/NIRCam photometry that covers the rest-UV to the optical from the GLASS and UNCOVER JWST surveys. Our s le includes 102 galaxies with Lyman-alpha emission detected in MUSE spectroscopy. We used H α fluxes inferred from NIRCam photometry to estimate the production rate of ionizing photons that do not escape these galaxies, ξ ion (1 − f esc ). Results. We find median log 10 ξ ion (1 − f esc ) = 25.33 ± 0.47, with a broad intrinsic scatter of 0.42 dex, which implies a broad range of galaxy properties and ages in our UV-faint s le. Galaxies detected with Lyman-alpha have ∼0.1 dex higher ξ ion (1 − f esc ), which is explained by their higher H α equivalent width distribution this implies younger ages and higher specific star formation rates and, thus, more O/B stars. We find significant trends of increasing ξ ion (1 − f esc ) with increasing H α equivalent width, decreasing UV luminosity, and decreasing UV slope this implies that the production of ionizing photons is enhanced in young galaxies with assumed low metallicities. We find no significant evidence for sources with very high ionizing escape fractions ( f esc 0.5) in our s le based on their photometric properties, even amongst the Lyman-alpha-selected galaxies. Conclusions. This work demonstrates that considering the full distribution of ξ ion across galaxy properties is important for assessing the primary drivers of reionization.
Publisher: American Astronomical Society
Date: 09-08-2016
Publisher: American Astronomical Society
Date: 20-03-2017
Publisher: American Astronomical Society
Date: 10-10-2016
Publisher: American Astronomical Society
Date: 24-07-2019
Publisher: American Astronomical Society
Date: 07-11-2016
Publisher: American Astronomical Society
Date: 12-03-2015
Publisher: American Astronomical Society
Date: 22-04-2016
Publisher: American Astronomical Society
Date: 06-09-2019
Publisher: American Astronomical Society
Date: 07-2023
Abstract: We present images and a multiwavelength photometric catalog based on all of the JWST NIRCam observations obtained to date in the region of the Abell 2744 galaxy cluster. These data come from three different programs, namely, the GLASS-JWST Early Release Science Program, UNCOVER, and the Director’s Discretionary Time program 2756. The observed area in the NIRCam wide-band filters—covering the central and extended regions of the cluster, as well as new parallel fields—is 46.5 arcmin 2 in total. All images in eight bands (F090W, F115W, F150W, F200W, F277W, F356W, F410M, and F444W) have been reduced adopting the latest calibration and reference files available. Data reduction has been performed using an augmented version of the official JWST pipeline, with improvements aimed at removing or mitigating defects in the raw images and improving the background subtraction and photometric accuracy. We obtain an F444W-detected multiband catalog, including all NIRCam and available Hubble Space Telescope data, adopting forced-aperture photometry on point-spread-function-matched images. The catalog is intended to enable early scientific investigations and is optimized for the study of faint galaxies it contains 24,389 sources, with a 5 σ limiting magnitude in the F444W band ranging from 28.5 AB to 30.5 AB, as a result of the varying exposure times of the surveys that observed the field. We publicly release the reduced NIRCam images, associated multiwavelength catalog, and the code adopted for 1/ f noise removal with the aim of aiding users in familiarizing themselves with JWST NIRCam data and identifying suitable targets for follow-up observations.
Publisher: Oxford University Press (OUP)
Date: 16-08-2023
Abstract: We present the JWST cycle 1 53.8 h medium program FRESCO, short for ‘First Reionization Epoch Spectroscopically Complete Observations’. FRESCO covers 62 arcmin2 in each of the two GOODS/CANDELS fields for a total area of 124 arcmin2 exploiting JWST’s powerful new grism spectroscopic capabilities at near-infrared wavelengths. By obtaining ∼2 h deep NIRCam/grism observations with the F444W filter, FRESCO yields unprecedented spectra at R ∼ 1600 covering 3.8–5.0 µm for most galaxies in the NIRCam field of view. This setup enables emission line measurements over most of cosmic history, from strong PAH lines at z ∼ 0.2–0.5, to Pa α and Pa β at z ∼ 1–3, He i and [S iii] at z ∼ 2.5–4.5, H α and [N ii] at z ∼ 5–6.5, up to [O iii] and H β for z ∼ 7–9 galaxies. FRESCO’s grism observations provide total line fluxes for accurately estimating galaxy stellar masses and calibrating slit-loss corrections of NIRSpec/MSA spectra in the same field. Additionally, FRESCO results in a mosaic of F182M, F210M, and F444W imaging in the same fields to a depth of ∼28.2 mag (5σ in 0${_{.}^{\\prime\\prime}}$32 diameter apertures). Here, we describe the overall survey design and the key science goals that can be addressed with FRESCO. We also highlight several, early science results, including: spectroscopic redshifts of Lyman break galaxies that were identified almost 20 yr ago, the discovery of broad-line active galactic nuclei at z & 4, and resolved Pa α maps of galaxies at z ∼ 1.4. These results demonstrate the enormous power for serendipitous discovery of NIRCam/grism observations.
Publisher: American Astronomical Society
Date: 09-04-2019
Publisher: American Astronomical Society
Date: 11-08-2016
Publisher: American Astronomical Society
Date: 28-09-2022
Abstract: Galaxy sizes and their evolution over cosmic time have been studied for decades and serve as key tests of galaxy formation models. However, at z ≳ 1 these studies have been limited by a lack of deep, high-resolution rest-frame infrared imaging that accurately traces stellar mass distributions. Here, we leverage the new capabilities of the James Webb Space Telescope (JWST) to measure the 4.4 μ m sizes of ∼1000 galaxies with log M * / M ⊙ ≥ 9 and 1.0 ≤ z ≤ 2.5 from public CEERS imaging in the Extended Groth Strip deep field. We compare the sizes of galaxies measured from NIRCam imaging at 4.4 μ m ( λ rest ∼ 1.6 μ m) with sizes measured at 1.5 μ m ( λ rest ∼ 5500 Å). We find that, on average, galaxy half-light radii are ∼9% smaller at 4.4 μ m than 1.5 μ m in this s le. This size difference is markedly stronger at higher stellar masses and redder rest-frame V − J colors: galaxies with M * ∼ 10 11 M ⊙ have 4.4 μ m sizes that are ∼30% smaller than their 1.5 μ m sizes. Our results indicate that galaxy mass profiles are significantly more compact than their rest-frame optical light profiles at cosmic noon, and demonstrate that spatial variations in age and attenuation are important, particularly for massive galaxies. The trend we find here impacts our understanding of the size growth and evolution of galaxies, and suggests that previous studies based on rest-frame optical light may not have captured the mass-weighted structural evolution of galaxies. This paper represents a first step toward a new understanding of the morphologies of early massive galaxies enabled by JWST’s infrared window into the distant universe.
Publisher: American Astronomical Society
Date: 11-2022
Abstract: The gravitationally lensed star WHL 0137–LS, nicknamed Earendel, was identified with a photometric redshift z phot = 6.2 ± 0.1 based on images taken with the Hubble Space Telescope. Here we present James Webb Space Telescope (JWST) Near Infrared Camera images of Earendel in eight filters spanning 0.8–5.0 μ m. In these higher-resolution images, Earendel remains a single unresolved point source on the lensing critical curve, increasing the lower limit on the lensing magnification to μ 4000 and restricting the source plane radius further to r 0.02 pc, or ∼4000 au. These new observations strengthen the conclusion that Earendel is best explained by an in idual star or multiple star system and support the previous photometric redshift estimate. Fitting grids of stellar spectra to our photometry yields a stellar temperature of T eff ≃ 13,000–16,000 K, assuming the light is dominated by a single star. The delensed bolometric luminosity in this case ranges from log ( L ) = 5.8 to 6.6 L ⊙ , which is in the range where one expects luminous blue variable stars. Follow-up observations, including JWST NIRSpec scheduled for late 2022, are needed to further unravel the nature of this object, which presents a unique opportunity to study massive stars in the first billion years of the universe.
Publisher: American Astronomical Society
Date: 02-2021
Abstract: We examine the Fundamental Plane (FP) and mass-to-light ratio ( M / L ) scaling relations using the largest s le of massive quiescent galaxies at 1.5 z 2.5 to date. The FP ( r e , σ e , I e ) is established using 19 UVJ quiescent galaxies from COSMOS with Hubble Space Telescope H F 160 W rest-frame optical sizes and X-shooter absorption line-measured stellar velocity dispersions. For a very massive, log ( M * / M ⊙ ) 11.26 , subset of eight quiescent galaxies at z 2, from Stockmann et al., we show that they cannot passively evolve to the local Coma cluster relation alone and must undergo significant structural evolution to mimic the sizes of local massive galaxies. The evolution of the FP and M / L scaling relations, from z = 2 to present day, for this subset are consistent with passive aging of the stellar population and minor merger structural evolution into the most massive galaxies in the Coma cluster and other massive elliptical galaxies from the MASSIVE Survey. Modeling the luminosity evolution from minor merger-added stellar populations favors a history of merging with “dry” quiescent galaxies.
Publisher: American Astronomical Society
Date: 05-2023
Abstract: With just a month of data, JWST is already transforming our view of the universe, revealing and resolving starlight in unprecedented populations of galaxies. Although “HST-dark” galaxies have previously been detected at long wavelengths, these observations generally suffer from a lack of spatial resolution, which limits our ability to characterize their sizes and morphologies. Here we report on a first view of starlight from a subset of the HST-dark population that is bright with JWST/NIRCam (4.4 μ m 24.5 mag) and very faint or even invisible with HST ( .6 μ m). In this Letter we focus on a dramatic and unanticipated population of physically extended galaxies (≳0.″25). These 12 galaxies have photometric redshifts 2 z 6, high stellar masses M ⋆ ≳ 10 10 M ⊙ , and significant dust-attenuated star formation. Surprisingly, the galaxies have elongated projected axis ratios at 4.4 μ m, suggesting that the population is disk dominated or prolate and we hence refer to them as ultrared flattened objects. Most of the galaxies appear red at all radii, suggesting significant dust attenuation throughout. With R e (F444W) ∼ 1–2 kpc, the galaxies are similar in size to compact massive galaxies at z ∼ 2 and the cores of massive galaxies and S0s at z ∼ 0. The stellar masses, sizes, and morphologies of the s le suggest that some could be progenitors of lenticular or fast-rotating galaxies in the local universe. The existence of this population suggests that our previous censuses of the universe may have missed massive, dusty edge-on disks, in addition to dust-obscured starbursts.
Publisher: American Astronomical Society
Date: 03-11-2016
Publisher: American Astronomical Society
Date: 23-07-2015
Publisher: American Astronomical Society
Date: 02-09-2015
Publisher: American Astronomical Society
Date: 06-2023
Abstract: MACS0647–JD is a triply lensed z ∼ 11 galaxy originally discovered with the Hubble Space Telescope. The three lensed images are magnified by factors of ∼8, 5, and 2 to AB mag 25.1, 25.6, and 26.6 at 3.5 μ m. The brightest is over a magnitude brighter than other galaxies recently discovered at similar redshifts z 10 with JWST. Here, we report new JWST imaging that clearly resolves MACS0647–JD as having two components that are either merging galaxies or stellar complexes within a single galaxy. The brighter larger component “A” is intrinsically very blue ( β ∼ −2.6 ± 0.1), likely due to very recent star formation and no dust, and is spatially extended with an effective radius ∼70 ± 24 pc. The smaller component “B” ( r ∼ 20 − 5 + 8 pc) appears redder ( β ∼ −2 ± 0.2), likely because it is older (100–200 Myr) with mild dust extinction ( A V ∼ 0.1 mag). With an estimated stellar mass ratio of roughly 2:1 and physical projected separation ∼400 pc, we may be witnessing a galaxy merger 430 million years after the Big Bang. We identify galaxies with similar colors in a high-redshift simulation, finding their star formation histories to be dissimilar, which is also suggested by the spectral energy distribution fitting, suggesting they formed further apart. We also identify a candidate companion galaxy “C” ∼3 kpc away, likely destined to merge with A and B. Upcoming JWST Near Infrared Spectrograph observations planned for 2023 January will deliver spectroscopic redshifts and more physical properties for these tiny magnified distant galaxies observed in the early universe.
Publisher: American Astronomical Society
Date: 10-2022
Abstract: We report the first gas-phase metallicity map of a distant galaxy measured with the James Webb Space Telescope (JWST). We use the NIRISS slitless spectroscopy acquired by the GLASS Early Release Science program to spatially resolve the rest-frame optical nebular emission lines in a gravitationally lensed galaxy at z = 3.06 behind the A2744 galaxy cluster. This galaxy (dubbed GLASS-Zgrad1) has stellar mass ∼10 8.6 M ⊙ , instantaneous star formation rate ∼8.6 M ⊙ yr −1 (both corrected for lensing magnification), and global metallicity one-fourth solar. From its emission-line maps ([O iii ], H β , H γ , [Ne iii ], and [O ii ]), we derive its spatial distribution of gas-phase metallicity using a well-established forward-modeling Bayesian inference method. The exquisite resolution and sensitivity of JWST/NIRISS, combined with lensing magnification, enable us to resolve this z ∼ 3 dwarf galaxy in ≳50 resolution elements with sufficient signal, an analysis hitherto not possible. We find that the radial metallicity gradient of GLASS-Zgrad1 is strongly inverted (i.e., positive): Δ log ( O / H ) / Δ r = 0.165 ± 0.023 dex kpc −1 . This measurement is robust at ≳ 4 − σ confidence level against known systematics. This positive gradient may be due to tidal torques induced by a massive nearby (∼15 kpc projected) galaxy, which can cause inflows of metal-poor gas into the central regions of GLASS-Zgrad1. These first results showcase the power of JWST wide-field slitless spectroscopic modes to resolve the mass assembly and chemical enrichment of low-mass galaxies in and beyond the peak epoch of cosmic star formation ( z ≳ 2). Reaching masses ≲ 10 9 M ⊙ at these redshifts is especially valuable to constrain the effects of galactic feedback and environment and is possible only with JWST’s new capabilities.
Publisher: American Astronomical Society
Date: 21-09-2017
Publisher: American Astronomical Society
Date: 05-06-2019
Publisher: American Astronomical Society
Date: 22-06-2017
Publisher: American Astronomical Society
Date: 07-2021
Publisher: American Astronomical Society
Date: 17-05-2017
Publisher: American Astronomical Society
Date: 16-09-2015
Publisher: American Astronomical Society
Date: 14-10-2015
Publisher: American Astronomical Society
Date: 19-03-2020
Publisher: American Astronomical Society
Date: 03-11-2014
Publisher: Springer Science and Business Media LLC
Date: 22-02-2023
Publisher: EDP Sciences
Date: 04-2023
DOI: 10.1051/0004-6361/202345866
Abstract: The escape fraction of Lyman-continuum (LyC) photons ( f esc ) is a key parameter for determining the sources of cosmic reionization at z ≥ 6. At these redshifts, owing to the opacity of the intergalactic medium, the LyC emission cannot be measured directly. However, LyC leakers during the epoch of reionization could be identified using indirect indicators that have been extensively tested at low and intermediate redshifts. These include a high [O III ]/[O II ] flux ratio, high star-formation surface density, and compact sizes. In this work, we present observations of 29 4.5 ≤ z ≤ 8 gravitationally lensed galaxies in the Abell 2744 cluster field. From a combined analysis of JWST-NIRSpec and NIRCam data, we accurately derived their physical and spectroscopic properties: our galaxies have low masses (log( M ⋆ )∼8.5), blue UV spectral slopes ( β ∼ −2.1), compact sizes ( r e ∼ 0.3 − 0.5 kpc), and high [O III ]/[O II ] flux ratios. We confirm that these properties are similar to those characterizing low-redshift LyC leakers. Indirectly inferring the fraction of escaping ionizing photons, we find that more than 80% of our galaxies have predicted f esc values larger than 0.05, indicating that they would be considered leakers. The average predicted f esc value of our s le is 0.12, suggesting that similar galaxies at z ≥ 6 have provided a substantial contribution to cosmic reionization.
Publisher: Springer Science and Business Media LLC
Date: 21-09-2023
Publisher: Springer Science and Business Media LLC
Date: 25-10-2023
Publisher: American Astronomical Society
Date: 07-03-2017
Publisher: Oxford University Press (OUP)
Date: 27-04-2023
Abstract: Using CANUCS imaging we found an apparent major merger of two $z$ ∼ 5 ultra-low-mass galaxies (M⋆∼107M⊙ each) that are doubly imaged and magnified ∼12–15× by the lensing cluster MACS 0417. Both galaxies are experiencing young (∼100 Myr), synchronised bursts of star formation with log (sSFR/Gyr−1) ∼1.3–1.4, yet SFRs of just ∼0.2M⊙ yr−1. They have sub-solar (Z ∼ 0.2Z⊙) gas-phase metallicities and are connected by an even more metal-poor star-forming bridge. The galaxy that forms from the merger will have a mass of at least M⋆∼2 × 107 M⊙, at least half of it formed during the interaction-induced starburst. More than half of the ionizing photons produced by the system (before and during the merger) will have been produced during the burst. This system provides the first detailed look at a merger involving two high-$z$ ultra-low-mass galaxies of the type believed to be responsible for reionizing the Universe. It suggests that such galaxies can grow via a combination of mass obtained through major mergers, merger-triggered starbursts, and long-term in-situ star formation. If such high-$z$ mergers are common, then merger-triggered starbursts could be significant contributors to the ionizing photon budget of the Universe.
Publisher: American Astronomical Society
Date: 29-03-2016
Publisher: American Astronomical Society
Date: 15-09-2020
Publisher: American Astronomical Society
Date: 29-10-2014
Publisher: American Astronomical Society
Date: 05-12-2018
Publisher: American Astronomical Society
Date: 11-2022
Abstract: The first few 100 Myr at z 10 mark the last major uncharted epoch in the history of the universe, where only a single galaxy (GN-z11 at z ≈ 11) is currently spectroscopically confirmed. Here we present a search for luminous z 10 galaxies with JWST/NIRCam photometry spanning ≈1–5 μ m and covering 49 arcmin 2 from the public JWST Early Release Science programs (CEERS and GLASS). Our most secure candidates are two M UV ≈ −21 systems: GLASS-z12 and GLASS-z10. These galaxies display abrupt ≳1.8 mag breaks in their spectral energy distributions (SEDs), consistent with complete absorption of flux bluewards of Ly α that is redshifted to z = 12.4 − 0.3 + 0.1 and z = 10.4 − 0.5 + 0.4 . Lower redshift interlopers such as quiescent galaxies with strong Balmer breaks would be comfortably detected at σ in multiple bands where instead we find no flux. From SED modeling we infer that these galaxies have already built up ∼10 9 solar masses in stars over the ≲300–400 Myr after the Big Bang. The brightness of these sources enable morphological constraints. Tantalizingly, GLASS-z10 shows a clearly extended exponential light profile, potentially consistent with a disk galaxy of r 50 ≈ 0.7 kpc. These sources, if confirmed, join GN-z11 in defying number density forecasts for luminous galaxies based on Schechter UV luminosity functions, which require a survey area × larger than we have studied here to find such luminous sources at such high redshifts. They extend evidence from lower redshifts for little or no evolution in the bright end of the UV luminosity function into the cosmic dawn epoch, with implications for just how early these galaxies began forming. This, in turn, suggests that future deep JWST observations may identify relatively bright galaxies to much earlier epochs than might have been anticipated.
Publisher: American Astronomical Society
Date: 09-2023
Publisher: Oxford University Press (OUP)
Date: 03-02-2020
Abstract: We present a catalogue of 22 755 objects with slitless, optical, Hubble Space Telescope (HST) spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS). The data cover ∼220 sq. arcmin to 7-orbit (∼10 ks) depth in 20 parallel pointings of the Advanced Camera for Survey’s G800L grism. The fields are located 6 arcmin away from 10 massive galaxy clusters in the HFF and CLASH footprints. 13 of the fields have ancillary HST imaging from these or other programs to facilitate a large number of applications, from studying metal distributions at z ∼ 0.5, to quasars at z ∼ 4, to the star formation histories of hundreds of galaxies in between. The spectroscopic catalogue has a median redshift of 〈z〉 = 0.60 with a median uncertainty of $\\Delta z / (1+z)\\lesssim 2{{\\ \\rm per\\ cent}}$ at $F814\\mathit{ W}\\lesssim 23$ AB. Robust continuum detections reach a magnitude fainter. The 5 σ limiting line flux is $f_{\\rm lim}\\approx 5\\times 10^{-17}\\rm ~erg~s^{-1}~cm^{-2}$ and half of all sources have 50 per cent of pixels contaminated at ≲1 per cent. All sources have 1D and 2D spectra, line fluxes/uncertainties and identifications, redshift probability distributions, spectral models, and derived narrow-band emission-line maps from the Grism Redshift and Line Analysis tool (grizli). We provide other basic s le characterizations, show data ex les, and describe sources and potential investigations of interest. All data and products will be available online along with software to facilitate their use.
Publisher: American Astronomical Society
Date: 10-2022
Abstract: We present the reduced images and multiwavelength catalog of the first JWST NIRCam extragalactic observations from the GLASS Early Release Science Program, obtained as coordinated parallels of the NIRISS observations of the Abell 2744 cluster. Images in seven bands (F090W, F115W, F150W, F200W, F277W, F356W, and F444W) have been reduced using an augmented version of the official JWST pipeline we discuss the procedures adopted to remove or mitigate defects in the raw images. We obtain a multiband catalog by means of forced aperture photometry on point-spread function (PSF)-matched images at the position of F444W-detected sources. The catalog is intended to enable early scientific investigations, and it is optimized for faint galaxies it contains 6368 sources, with limiting magnitude 29.7 at 5 σ in F444W. We release both images and catalog in order to allow the community to become familiar with the JWST NIRCam data and evaluate their merit and limitations given the current level of knowledge of the instrument.
Publisher: American Astronomical Society
Date: 23-03-2201
Publisher: American Astronomical Society
Date: 23-06-2014
Publisher: American Astronomical Society
Date: 08-06-2017
Publisher: American Astronomical Society
Date: 2023
Abstract: How passive galaxies form, and the physical mechanisms which prevent star formation over long timescales, are some of the most outstanding questions in understanding galaxy evolution. The properties of quiescent galaxies over cosmic time provide crucial information to identify the quenching mechanisms. Passive galaxies have been confirmed and studied out to z ∼ 4, but all of these studies have been limited to massive systems (mostly with log ( M star / M ⊙ ) 10.8 ). Using JWST-NIRISS grism slitless spectroscopic data from the GLASS-JWST Early Release Science program, we present spectroscopic confirmation of two quiescent galaxies at z spec = 2.650 − 0.006 + 0.004 and z spec = 2.433 − 0.016 + 0.032 (3 σ errors) with stellar masses of log ( M star / M ⊙ ) = 10.59 − 0.05 + 0.11 and log ( M star / M ⊙ ) = 10.07 − 0.03 + 0.06 (corrected for magnification factors of μ = 2.0 and μ = 2.1, respectively). The latter represents the first spectroscopic confirmation of the existence of low-mass quiescent galaxies at cosmic noon, showcasing the power of JWST to identify and characterize this enigmatic population.
Publisher: American Astronomical Society
Date: 22-09-2015
Publisher: American Astronomical Society
Date: 31-08-2018
Publisher: American Astronomical Society
Date: 04-05-2018
Publisher: American Astronomical Society
Date: 26-10-2023
Publisher: American Astronomical Society
Date: 29-05-2015
Publisher: American Astronomical Society
Date: 14-03-2017
Publisher: American Astronomical Society
Date: 25-03-2019
Publisher: American Astronomical Society
Date: 19-03-2018
Publisher: American Astronomical Society
Date: 05-2023
Abstract: We present the first results on the spatial distribution of dust attenuation at 1.0 z 2.4 traced by the Balmer decrement, H α /H β , in emission-line galaxies using deep JWST NIRISS slitless spectroscopy from the CAnadian NIRISS Unbiased Cluster Survey (CANUCS). H α and H β emission-line maps of emission-line galaxies are extracted and stacked in bins of stellar mass for two grism redshift bins, 1.0 z grism 1.7 and 1.7 z grism 2.4. Surface brightness profiles for the Balmer decrement are measured and radial profiles of the dust attenuation toward H α , A H α , are derived. In both redshift bins, the integrated Balmer decrement increases with stellar mass. Lower-mass (7.6 ≤ Log( M * / M ⊙ ) 10.0) galaxies have centrally concentrated, negative dust attenuation profiles whereas higher-mass galaxies (10.0 ≤ Log( M * / M ⊙ ) 11.1) have flat dust attenuation profiles. The total dust obscuration is mild, with on average 0.07 ± 0.07 and 0.14 ± 0.07 mag in the low- and high-redshift bins respectively. We model the typical light profiles of star-forming galaxies at these redshifts and stellar masses with GALFIT and apply both uniform and radially varying dust attenuation corrections based on our integrated Balmer decrements and radial dust attenuation profiles. If the H α star formation rates (SFRs) of these galaxies were measured after slit-loss corrections assuming uniform dust attenuation with typical JWST NIRSpec slit spectroscopy (0.″2 × 0.″5 shutters), the total SFR will be overestimated by 6% ± 21% and 26% ± 9% at 1.0 ≤ z 1.7 and 1.7 ≤ z 2.4 respectively.
Publisher: American Astronomical Society
Date: 09-2022
Abstract: We use deep spectroscopy from the Hubble Space Telescope Wide-Field-Camera 3 IR grisms combined with broadband photometry to study the stellar populations, gas ionization and chemical abundances in star-forming galaxies at z ∼ 1.1–2.3. The data stem from the CANDELS Ly α Emission At Reionization (CLEAR) survey. At these redshifts, the grism spectroscopy measure the [O II ] λ λ 3727, 3729, [O III ] λ λ 4959, 5008, and H β strong emission features, which constrain the ionization parameter and oxygen abundance of the nebular gas. We compare the line-flux measurements to predictions from updated photoionization models (MAPPINGS V Kewley et al.), which include an updated treatment of nebular gas pressure, log P / k = n e T e . Compared to low-redshift s les ( z ∼ 0.2) at fixed stellar mass, log M * / M ⊙ = 9.4–9.8, the CLEAR galaxies at z = 1.35 (1.90) have lower gas-phase metallicity, Δ ( log Z ) = 0.25 (0.35) dex, and higher ionization parameters, Δ ( log q ) = 0.25 (0.35) dex, where U ≡ q / c . We provide updated analytic calibrations between the [O III ], [O II ], and H β emission-line ratios, metallicity, and ionization parameter. The CLEAR galaxies show that at fixed stellar mass, the gas ionization parameter is correlated with the galaxy specific star formation rates, where Δ log q ≃ 0.4 × Δ ( log sSFR ) , derived from changes in the strength of galaxy H β equivalent width. We interpret this as a consequence of higher gas densities, lower gas covering fractions, combined with a higher escape fraction of H-ionizing photons. We discuss both tests to confirm these assertions and implications this has for future observations of galaxies at higher redshifts.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2023
Publisher: Research Square Platform LLC
Date: 24-07-2023
DOI: 10.21203/RS.3.RS-3135743/V1
Abstract: The mergers of binary compact objects such as neutron stars and black holes are of central interest to several areas of astrophysics, including as the progenitors of gamma-ray bursts (GRBs), sources of high-frequency gravitational waves and likely production sites for heavy element nucleosynthesis via rapid neutron capture (the r-process). These heavy elements include some of great geophysical, biological and cultural importance, such as thorium, iodine, and gold. Here we present observations of the exceptionally bright gamma-ray burst GRB230307A. We show that GRB 230307A belongs to the class of long-duration gamma-ray bursts associated with compact object mergers, and contains a kilonova similar to AT2017gfo, associated with the gravitational-wave merger GW170817. We obtained James Webb Space Telescope mid-infrared (mid-IR) imaging and spectroscopy 29 & 61 days after the burst. The spectroscopy shows an emission line at 2.1 microns which we interpret as tellurium (atomic mass A=130), and a very red source, emitting most of its light in the mid-IR due to the production of lanthanides. These observations demonstrate that nucleosynthesis in GRBs can create r-process elements across a broad atomic mass range and play a central role in heavy element nucleosynthesis across the Universe.
Publisher: American Astronomical Society
Date: 07-2023
Abstract: We report ALMA detections of [C ii ] and a dust continuum in Az9, a multiply imaged galaxy behind the Frontier Field cluster MACS J0717.5+3745. The bright [C ii ] emission line provides a spectroscopic redshift of z = 4.274. This strongly lensed ( μ = 7 ± 1) galaxy has an intrinsic stellar mass of only 2 × 10 9 M ⊙ and a total star formation rate of 26 M ⊙ yr −1 (∼80% of which is dust-obscured). Using public magnification maps, we reconstruct the [C ii ] emission in the source plane to reveal a stable, rotation-dominated disk with V / σ = 5.3, which is × higher than predicted from simulations for similarly high-redshift, low-mass galaxies. In the source plane, the [C ii ] disk has a half-light radius of 1.8 kpc and, along with the dust, is spatially offset from the peak of the stellar light by 1.4 kpc. Az9 is not deficient in [C ii ] L [C II ] / L IR = 0.0027, consistent with local and high-redshift normal star-forming galaxies. While dust-obscured star formation is expected to dominate in higher-mass galaxies, such a large reservoir of dust and gas in a lower-mass disk galaxy 1.4 Gyr after the Big Bang challenges our picture of early galaxy evolution. Furthermore, the prevalence of such low-mass dusty galaxies has important implications for the selection of the highest-redshift dropout galaxies with JWST. As one of the lowest stellar mass galaxies at z 4 to be detected in a dust continuum and [C ii ], Az9 is an excellent laboratory in which to study early dust enrichment in the interstellar medium.
Start Date: 2014
End Date: 12-2017
Amount: $360,000.00
Funder: Australian Research Council
View Funded Activity