The BUFFALO HST Survey Steinhardt, Charles L.; Jauzac, Mathilde; Acebron, Ana ...
The Astrophysical journal. Supplement series,
04/2020, Letnik:
247, Številka:
2
Journal Article
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The Beyond Ultra-deep Frontier Fields and Legacy Observations (BUFFALO) is a 101 orbit + 101 parallel Cycle 25 Hubble Space Telescope (HST) Treasury program taking data from 2018 to 2020. BUFFALO ...will expand existing coverage of the Hubble Frontier Fields (HFF) in Wide Field Camera 3/IR F105W, F125W, and F160W and Advanced Camera for Surveys/WFC F606W and F814W around each of the six HFF clusters and flanking fields. This additional area has not been observed by HST but is already covered by deep multiwavelength data sets, including Spitzer and Chandra. As with the original HFF program, BUFFALO is designed to take advantage of gravitational lensing from massive clusters to simultaneously find high-redshift galaxies that would otherwise lie below HST detection limits and model foreground clusters to study the properties of dark matter and galaxy assembly. The expanded area will provide the first opportunity to study both cosmic variance at high redshift and galaxy assembly in the outskirts of the large HFF clusters. Five additional orbits are reserved for transient follow-up. BUFFALO data including mosaics, value-added catalogs, and cluster mass distribution models will be released via MAST on a regular basis as the observations and analysis are completed for the six individual clusters.
Abstract
We study the spatially resolved stellar populations of 444 galaxies at 0.3 <
z
< 6.0 in two clusters (WHL 0137–08 and MACS 0647+70) and a blank field, combining imaging data from the Hubble ...Space Telescope and JWST to perform spatially resolved spectral energy distribution (SED) modeling using
piXedfit
. The high spatial resolution of the imaging data combined with magnification from gravitational lensing in the cluster fields allows us to resolve a large fraction of our galaxies (109) to subkiloparsec scales. At redshifts around cosmic noon and higher (2.5 ≲
z
≲ 6.0), we find mass-doubling times to be independent of radius, inferred from flat specific star formation rate (sSFR) radial profiles and similarities between the half-mass and half-SFR radii. At lower redshifts (1.5 ≲
z
≲ 2.5), a significant fraction of our star-forming galaxies shows evidence for nuclear starbursts, inferred from a centrally elevated sSFR and a much smaller half-SFR radius compared to the half-mass radius. At later epochs, we find more galaxies suppress star formation in their centers but are still actively forming stars in the disk. Overall, these trends point toward a picture of inside-out galaxy growth consistent with theoretical models and simulations. We also observe a tight relationship between the central mass surface density and global stellar mass with ∼0.38 dex scatter. Our analysis demonstrates the potential of spatially resolved SED analysis with JWST data. Future analysis with larger samples will be able to further explore the assembly of galaxy mass and the growth of their structures.
We present the largest search to date for Y-band dropout galaxies (z ~ 8 Lyman break galaxies, LBGs) based on 350 arcmin super(2) of Hubble Space Telescope observations in the V, Y, J, and H bands ...from the Brightest of Reionizing Galaxies (BoRG) survey. We introduce a new Bayesian formalism for estimating the galaxy luminosity function, which does not require binning (and thus smearing) of the data and includes a likelihood based on the formally correct binomial distribution as opposed to the often-used approximate Poisson distribution. We demonstrate the utility of the new method on a sample of 97 Y-band dropouts that combines the bright BoRG galaxies with the fainter sources published in Bouwens et al. from the Hubble Ultra Deep Field and Early Release Science programs. The data are consistent with a substantial fraction of neutral hydrogen at z > 7, in agreement with recent suggestions based on deep spectroscopy of z ~ 8 LBGs.
We present a new method for photometering objects in galaxy clusters. We introduce a mode-filtering technique for removing spatially variable backgrounds, improving both detection and photometric ...accuracy (roughly halving the scatter in the red sequence compared to previous catalogs of the same clusters). This method is based on robustly determining the distribution of background pixel values and should provide comparable improvement in photometric analysis of any crowded fields. We produce new multiwavelength catalogs for the 25 CLASH cluster fields in all 16 bandpasses from the UV through the near-IR, as well as rest-frame magnitudes. A comparison with spectroscopic values from the literature finds a decrease in the redshift deviation from previously released CLASH photometry. This improvement in redshift precision, in combination with a detection scheme designed to maximize purity, yields a substantial upgrade in cluster member identification over the previous CLASH galaxy catalog. We construct luminosity functions for each cluster, reliably reaching depths of at least 4.5 mag below M* in every case, and deeper still in several clusters. We measure M* , , and their redshift evolution, assuming the cluster populations are coeval, and find little to no evolution of , and M* values consistent with passive evolution. We present a catalog of galaxy photometry, photometric and spectroscopic redshifts, and rest-frame photometry for the full fields of view of all 25 CLASH clusters. Not only will our new photometric catalogs enable new studies of the properties of CLASH clusters, but mode-filtering techniques, such as those presented here, should greatly enhance the data quality of future photometric surveys of crowded fields.
Abstract
We present results of C
ii
158
μ
m emission line observations, and report the spectroscopic redshift confirmation of a strongly lensed (
μ
∼ 20) star-forming galaxy, MACS0308-zD1 at
z
= ...6.2078 ± 0.0002. The C
ii
emission line is detected with a signal-to-noise ratio >6 within the rest-frame UV-bright clump of the lensed galaxy (zD1.1) and exhibits multiple velocity components; the narrow C
ii
has a velocity full width half maximum (FWHM) of 110 ± 20 km s
−1
, while broader C
ii
is seen with an FWHM of 230 ± 50 km s
−1
. The broader C
ii
component is blueshifted (−80 ± 20 km s
−1
) with respect to the narrow C
ii
component, and has a morphology that extends beyond the UV-bright clump. We find that, while the narrow C
ii
emission is most likely associated with zD1.1, the broader component is possibly associated with a physically distinct gas component from zD1.1 (e.g., outflowing or inflowing gas). Based on the nondetection of
λ
158
μ
m
dust continuum, we find that MACS0308-zD1's star formation activity occurs in a dust-free environment indicated by a strong upper limit of infrared luminosity ≲9 × 10
8
L
⊙
. Targeting this strongly lensed faint galaxy for follow-up Atacama Large Millimeter/submillimeter Array and JWST observations will be crucial to characterize the details of typical galaxy growth in the early Universe.
Patient-reported outcomes (PROs) are becoming increasingly important to define successful outcomes. With the potential transition toward quality-based reimbursement, identifying risk factors for poor ...surgical outcomes becomes increasingly important. This study compared functional and PROs of primary shoulder arthroplasty in patients aged younger than 65 years with lower socioeconomic insurance compared with those with private insurance.
A retrospective review of all primary shoulder arthroplasties in patients aged younger than 65 was performed at a single institution. Patients were stratified according to insurance type (private vs. Medicare/Medicaid) with 2-year minimum follow-up. Preoperative, postoperative, and improvements in range of motion, visual analog scale (VAS) pain, and PROs were compared.
We evaluated 143 shoulders (64 Medicare/Medicaid, 79 private insurance). Age, race, diagnosis, and type of arthroplasty were similar between groups. Patients with Medicare/Medicaid insurance demonstrated worse PROs before and after surgery, despite similar range of motion at both assessments. Despite poorer PROs postoperatively, both groups demonstrated similar improvements after surgery. Complications and reoperation were more common in the socioeconomically disadvantaged group (14% vs. 9%, P = .3; 11% vs. 6%, P = .2, respectively).
Medicaid and Medicare patients aged younger than 65 years undergoing shoulder arthroplasty demonstrate poorer preoperative and postoperative PRO measures compared with similar patients with private insurance. However, both groups demonstrate similar improvements in scores from baseline.
We present a lens model for the cluster SPT-CLJ0615−5746, which is the highest-redshift (z = 0.972) system in the Reionization of Lensing Clusters Survey, making it the highest-redshift cluster for ...which a full, strong lens model is published. We identify three systems of multiply imaged lensed galaxies, two of which we spectroscopically confirm at z = 1.358 and z = 4.013, which we use as constraints for the model. We find a foreground structure at z ∼ 0.4, which we include as a second cluster-sized halo in one of our models; however, two different statistical tests find the best-fit model consists of one cluster-sized halo combined with three individually optimized galaxy-sized halos, as well as contributions from the cluster galaxies themselves. We find the total projected mass density within r = 26 7 (the region where the strong lensing constraints exist) to be M☉. If we extrapolate out to r500, our projected mass density is consistent with the mass inferred from weak lensing and from the Sunyaev-Zel'dovich effect (M ∼ 1015 M☉). This cluster is lensing a previously reported z ∼ 10 galaxy, which, if spectroscopically confirmed, will be the highest-redshift strongly lensed galaxy known.
ABSTRACT
Recent observations have revealed the presence of strong C iii emission (EW$_{\rm {C\,{\small III}}}\gt 20$ Å) in z > 6 galaxies, the origin of which remains unclear. In an effort to ...understand the nature of these line emitters, we have initiated a survey targeting C iii emission in gravitationally lensed reionization-era analogues identified in Hubble Space Telescope imaging of clusters from the Reionization Lensing Cluster Survey. Here, we report initial results on four galaxies selected to have low stellar masses (2–8 × 107 M⊙) and J125-band flux excesses indicative of intense O iii + H β emission (EW$_{\rm {O\,{\small III}+H\,\beta }}$ = 500–2000 Å), similar to what has been observed at z > 6. We detect C iii emission in three of the four sources, with the C iii EW reaching values seen in the reionization era (EW$_{\rm {C\,{\small III}}}\simeq 17\!-\!22$ Å) in the two sources with the strongest optical line emission (EW$_{\rm {O\,{\small III}+H\,\beta }}\simeq 2000$ Å). We have obtained a Magellan/FIRE (Folded-port InfraRed Echellette) near-infrared spectrum of the strongest C iii emitter in our sample, revealing gas that is both metal poor and highly ionized. Using photoionization models, we are able to simultaneously reproduce the intense C iii and optical line emission for extremely young (2–3 Myr) and metal-poor (0.06–0.08 Z⊙) stellar populations, as would be expected after a substantial upturn in the star formation rate of a low-mass galaxy. The sources in this survey are among the first for which C iii has been used as the primary means of redshift confirmation. We suggest that it should be possible to extend this approach to z > 6 with current facilities, using C iii to measure redshifts of objects with IRAC excesses indicating EW$_{\rm {O\,{\small III}+H\,\beta }}\simeq 2000$ Å, providing a method of spectroscopic confirmation independent of Ly α.
We have selected a sample of 11 massive clusters of galaxies observed by the Hubble Space Telescope in order to study the impact of the dynamical state on the intracluster light (ICL) fraction, the ...ratio of total integrated ICL to the total galaxy member light. With the exception of the Bullet cluster, the sample is drawn from the Cluster Lensing and Supernova Survey and the Frontier Fields program, containing five relaxed and six merging clusters. The ICL fraction is calculated in three optical filters using the CHEFs ICL estimator, a robust and accurate algorithm free of a priori assumptions. We find that the ICL fraction in the three bands is, on average, higher for the merging clusters, ranging between ∼7% and 23%, compared with the ∼2%-11% found for the relaxed systems. We observe a nearly constant value (within the error bars) in the ICL fraction of the regular clusters at the three wavelengths considered, which would indicate that the colors of the ICL and the cluster galaxies are, on average, coincident and, thus, so are their stellar populations. However, we find a higher ICL fraction in the F606W filter for the merging clusters, consistent with an excess of lower-metallicity/younger stars in the ICL, which could have migrated violently from the outskirts of the infalling galaxies during the merger event.
Strong gravitational lensing by galaxy clusters magnifies background galaxies, enhancing our ability to discover statistically significant samples of galaxies at , in order to constrain the ...high-redshift galaxy luminosity functions. Here, we present the first five lens models out of the Reionization Lensing Cluster Survey (RELICS) Hubble Treasury Program, based on new HST WFC3/IR and ACS imaging of the clusters RXC J0142.9+4438, Abell 2537, Abell 2163, RXC J2211.7-0349, and ACT-CLJ0102-49151. The derived lensing magnification is essential for estimating the intrinsic properties of high-redshift galaxy candidates, and properly accounting for the survey volume. We report on new spectroscopic redshifts of multiply imaged lensed galaxies behind these clusters, which are used as constraints, and detail our strategy to reduce systematic uncertainties due to lack of spectroscopic information. In addition, we quantify the uncertainty on the lensing magnification due to statistical and systematic errors related to the lens modeling process, and find that in all but one cluster, the magnification is constrained to better than 20% in at least 80% of the field of view, including statistical and systematic uncertainties. The five clusters presented in this paper span the range of masses and redshifts of the clusters in the RELICS program. We find that they exhibit similar strong lensing efficiencies to the clusters targeted by the Hubble Frontier Fields within the WFC3/IR field of view. Outputs of the lens models are made available to the community through the Mikulski Archive for Space Telescopes.
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