In this paper, we investigate the relationship between star formation and structure, using a mass-complete sample of 27,893 galaxies at 0.5 < z < 2.5 selected from 3D-HST. We confirm that ...star-forming galaxies are larger than quiescent galaxies at fixed stellar mass ( ). However, in contrast with some simulations, there is only a weak relation between star formation rate (SFR) and size within the star-forming population: when dividing into quartiles based on residual offsets in SFR, we find that the sizes of star-forming galaxies in the lowest quartile are 0.27 0.06 dex smaller than the highest quartile. We show that 50% of star formation in galaxies at fixed takes place within a narrow range of sizes (0.26 dex). Taken together, these results suggest that there is an abrupt cessation of star formation after galaxies attain particular structural properties. Confirming earlier results, we find that central stellar density within a 1 kpc fixed physical radius is the key parameter connecting galaxy morphology and star formation histories: galaxies with high central densities are red and have increasingly lower SFR/ , whereas galaxies with low central densities are blue and have a roughly constant (higher) SFR/ at a given redshift. We find remarkably little scatter in the average trends and a strong evolution of >0.5 dex in the central density threshold correlated with quiescence from z ∼ 0.7-2.0. Neither a compact size nor high-n are sufficient to assess the likelihood of quiescence for the average galaxy; instead, the combination of these two parameters together with results in a unique quenching threshold in central density/velocity.
We constrain the slope of the star formation rate (SFR; log Psi) to stellar mass (log M sub(*)) relation down to log(M sub(*)/M sub(middot in circle)) = 8.4 (log(M sub(*)/M sub(middot in circle)) = ...9.2) at z = 0.5 (z = 2.5) with a mass-complete sample of 39,106 star-forming galaxies selected from the 3D-HST photometric catalogs, using deep photometry in the CANDELS fields. For the first time, we find that the slope is dependent on stellar mass, such that it is steeper at low masses (log Psi is proportional to log M sub(*)) than at high masses (log Psi is proportional to (0.3-0.6) log M sub(*)). These steeper low-mass slopes are found for three different star formation indicators: the combination of the ultraviolet (UV) and infrared (IR), calibrated from a stacking analysis of Spitzer/MIPS 24 mu m imaging; beta -corrected UV SFRs; and H alpha SFRs. The normalization of the sequence evolves differently in distinct mass regimes as well: for galaxies less massive than log(M sub(*)/M sub(middot in circle)) < 10 the specific SFR (Psi/M sub(*)) is observed to be roughly self-similar with Psi/M sub(*) is proportional to (1 + z) super(1.9), whereas more massive galaxies show a stronger evolution with Psi/M sub(*) is proportional to (1 + z) super(2.2-3.5) for log(M sub(*)/M sub(middot in circle)) = 10.2-11.2. The fact that we find a steep slope of the star formation sequence for the lower mass galaxies will help reconcile theoretical galaxy formation models with the observations.
ABSTRACT We derive average radial gradients in the dust attenuation toward H ii regions in 609 galaxies at z ∼ 1.4, using measurements of the Balmer decrement out to r ∼ 3 kpc. The Balmer decrements ...are derived from spatially resolved maps of H and Hβ emission from the 3D-HST survey. We find that with increasing stellar mass M both the normalization and strength of the gradient in dust attenuation increases. Galaxies with a mean mass of M have little dust attenuation at all radii, whereas galaxies with M have AH 2 mag in their central regions. We parameterize this as , with , c = −1.9-2.2 log M10, r in kpc, and M10 the stellar mass in units of 1010 M . This expression can be used to correct spatially resolved measurements of H to radial distributions of star formation. When applied to our data, we find that the star formation rates (SFRs) in the central r < 1 kpc of galaxies in the highest mass bin are ∼6 M yr−1, six times higher than before correction and approximately half of the total SFR of these galaxies. If this high central SFR is maintained for several Gyr, a large fraction of the stars in present-day bulges likely formed in situ.
ABSTRACT We present reduced data and data products from the 3D-HST survey, a 248-orbit HST Treasury program. The survey obtained WFC3 G141 grism spectroscopy in four of the five CANDELS fields: ...AEGIS, COSMOS, GOODS-S, and UDS, along with WFC3 H140 imaging, parallel ACS G800L spectroscopy, and parallel I814 imaging. In a previous paper, we presented photometric catalogs in these four fields and in GOODS-N, the fifth CANDELS field. Here we describe and present the WFC3 G141 spectroscopic data, again augmented with data from GO-1600 in GOODS-N (PI: B. Weiner). We developed software to automatically and optimally extract interlaced two-dimensional (2D) and one-dimensional (1D) spectra for all objects in the Skelton et al. (2014) photometric catalogs. The 2D spectra and the multi-band photometry were fit simultaneously to determine redshifts and emission line strengths, taking the morphology of the galaxies explicitly into account. The resulting catalog has redshifts and line strengths (where available) for 22,548 unique objects down to (79,609 unique objects down to ). Of these, 5459 galaxies are at and 9621 are at , where H falls in the G141 wavelength coverage. The typical redshift error for galaxies is , i.e., one native WFC3 pixel. The limit for emission line fluxes of point sources is erg s−1 cm−2. All 2D and 1D spectra, as well as redshifts, line fluxes, and other derived parameters, are publicly available.18
The 3D-HST and CANDELS programs have provided WFC3 and ACS spectroscopy and photometry over approximate900 arcmin super(2) in five fields: AEGIS, COSMOS, GOODS-North, GOODS-South, and the UKIDSS UDS ...field. All these fields have a wealth of publicly available imaging data sets in addition to the Hubble Space Telescope (HST) data, which makes it possible to construct the spectral energy distributions (SEDs) of objects over a wide wavelength range. In this paper we describe a photometric analysis of the CANDELS and 3D-HST HST imaging and the ancillary imaging data at wavelengths 0.3-8Mum. Objects were selected in the WFC3 near-IR bands, and their SEDs were determined by carefully taking the effects of the point-spread function in each observation into account. A total of 147 distinct imaging data sets were used in the analysis. The photometry is made available in the form of six catalogs: one for each field, as well as a master catalog containing all objects in the entire survey. We also provide derived data products: photometric redshifts, determined with the EAZY code, and stellar population parameters determined with the FAST code. We make all the imaging data that were used in the analysis available, including our reductions of the WFC3 imaging in all five fields. 3D-HST is a spectroscopic survey with the WFC3 and ACS grisms, and the photometric catalogs presented here constitute a necessary first step in the analysis of these grism data. All the data presented in this paper are available through the 3D-HST Web site (http://3dhst.research.yale.edu).
ABSTRACT Using the UltraVISTA DR1 and 3D-HST catalogs, we construct a stellar-mass-complete sample, unique for its combination of surveyed volume and depth, to study the evolution of the fractions of ...quiescent galaxies, moderately unobscured star-forming galaxies, and dusty star-forming galaxies as a function of stellar mass over the redshift interval 0.2 ≤ z ≤ 3.0. We show that the role of dusty star-forming galaxies within the overall galaxy population becomes more important with increasing stellar mass and grows rapidly with increasing redshift. Specifically, dusty star-forming galaxies dominate the galaxy population with log ( M star / M ) 10.3 at z 2. The ratio of dusty and non-dusty star-forming galaxies as a function of stellar mass changes little with redshift. Dusty star-forming galaxies dominate the star-forming population at log ( M star / M ) 10.0 - 10.5 , being a factor of ∼3-5 more common, while unobscured star-forming galaxies dominate at log ( M star / M ) 10 . At log ( M star / M ) > 10.5 , red galaxies dominate the galaxy population at all redshift z < 3, either because they are quiescent (at late times) or dusty star-forming (in the early universe).
Abstract In this paper, we present the Heavy Metal Survey, which obtained ultradeep medium-resolution spectra of 21 massive quiescent galaxies at 1.3 < z < 2.3 with Keck/LRIS and MOSFIRE. With ...integration times of up to 16 hr per band per galaxy, we observe numerous Balmer and metal absorption lines in atmospheric windows. We successfully derive spectroscopic redshifts for all 21 galaxies, and for 19 we also measure stellar velocity dispersions ( σ v ), ages, and elemental abundances, as detailed in an accompanying paper. Except for one emission-line active galactic nucleus, all galaxies are confirmed as quiescent through their faint or absent H α emission and evolved stellar spectra. For most galaxies exhibiting faint H α , elevated N ii /H α suggests a non-star-forming origin. We calculate dynamical masses ( M dyn ) by combining σ v with structural parameters obtained from the Hubble Space Telescope COSMOS(-DASH) survey and compare them with stellar masses ( M * ) derived using spectrophotometric modeling, considering various assumptions. For a fixed initial mass function (IMF), we observe a strong correlation between M dyn / M * and σ v . This correlation may suggest that a varying IMF, with high- σ v galaxies being more bottom heavy, was already in place at z ∼ 2. When implementing the σ v -dependent IMF found in the cores of nearby early-type galaxies and correcting for biases in our stellar mass and size measurements, we find a low scatter in M dyn / M * of 0.14 dex. However, these assumptions result in unphysical stellar masses, which exceed the dynamical masses by 34%. This tension suggests that distant quiescent galaxies do not simply grow inside-out into today’s massive early-type galaxies and the evolution is more complicated.
CLEAR: Survey Overview, Data Analysis, and Products Simons, Raymond C.; Papovich, Casey; Momcheva, Ivelina G. ...
The Astrophysical journal. Supplement series,
05/2023, Volume:
266, Issue:
1
Journal Article
Peer reviewed
Open access
Abstract
We present an overview of the CANDELS Ly
α
Emission At Reionization (CLEAR) survey. CLEAR is a 130 orbit program of the Hubble Space Telescope using the Wide Field Camera 3 (WFC3) IR G102 ...grism. CLEAR targets 12 pointings divided between the GOODS-N and GOODS-S fields of the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). Combined with existing spectroscopic data from other programs, the full CLEAR data set includes spectroscopic imaging of these fields over 0.8–1.7
μ
m. In this paper, we describe the CLEAR survey, the survey strategy, the data acquisition, reduction, processing, and science products and catalogs released alongside this paper. The catalogs include emission line fluxes and redshifts derived from the combination of the photometry and grism spectroscopy for 6048 galaxies, primarily ranging from 0.2 ≲
z
≲ 3. We also provide an overview of CLEAR’s science goals and results. In conjunction with this paper we provide links to electronic versions of the data products, including 1D+2D extracted spectra and emission line maps.
ABSTRACT With a large, unique spectroscopic survey in the fields of 28 galaxy-scale strong gravitational lenses, we identify groups of galaxies in the 26 adequately sampled fields. Using a ...group-finding algorithm, we find 210 groups with at least 5 member galaxies; the median number of members is 8. Our sample spans redshifts of 0.04 ≤ zgrp ≤ 0.76 with a median of 0.31, including 174 groups with 0.1 < zgrp < 0.6. The groups have radial velocity dispersions of 60 ≤ grp ≤ 1200 km s−1 with a median of 350 km s−1. We also discover a supergroup in field B0712+472 at z = 0.29 that consists of three main groups. We recover groups similar to ∼85% of those previously reported in these fields within our redshift range of sensitivity and find 187 new groups with at least five members. The properties of our group catalog, specifically, (1) the distribution of grp, (2) the fraction of all sample galaxies that are group members, and (3) the fraction of groups with significant substructure, are consistent with those for other catalogs. The distribution of group virial masses agrees well with theoretical expectations. Of the lens galaxies, 12 of 26 (46%) (B1422+231, B1600+434, B2114+022, FBQS J0951+2635, HE0435-1223, HST J14113+5211, MG0751+2716, MGJ1654+1346, PG 1115+080, Q ER 0047-2808, RXJ1131-1231, and WFI J2033-4723) are members of groups with at least five galaxies, and one more (B0712+472) belongs to an additional, visually identified group candidate. There are groups not associated with the lens that still are likely to affect the lens model; in six of 25 (24%) fields (excluding the supergroup), there is at least one massive ( grp ≥ 500 km s−1) group or group candidate projected within 2′ of the lens.
Abstract
The 3D-Drift And SHift (3D-DASH) program is a Hubble Space Telescope (HST) WFC3 F160W imaging and G141 grism survey of the equatorial COSMOS field. 3D-DASH extends the legacy of HST ...near-infrared imaging and spectroscopy to degree-scale swaths of the sky, enabling the identification and study of distant galaxies (
z
> 2) that are rare or in short-lived phases of galaxy evolution at rest-frame optical wavelengths. Furthermore, when combined with existing ACS/F814W imaging, the program facilitates spatially resolved studies of the stellar populations and dust content of intermediate redshift (0.5 <
z
< 2) galaxies. Here we present the reduced F160W imaging mosaic available to the community. Observed with the efficient DASH technique, the mosaic comprises 1256 individual WFC3 pointings, corresponding to an area of 1.35 deg
2
(1.43 deg
2
in 1912 when including archival data). The median 5
σ
point-source limit in
H
160
is 24.74 ± 0.20 mag. We also provide a point-spread function (PSF) generator tool to determine the PSF at any location within the 3D-DASH footprint. 3D-DASH is the widest HST/WFC3 imaging survey in the F160W filter to date, increasing the existing extragalactic survey area in the near-infrared at HST resolution by an order of magnitude.
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