114 research outputs found
RELICS: The Reionization Lensing Cluster Survey and the Brightest High-z Galaxies
Massive foreground galaxy clusters magnify and distort the light of objects behind them, permitting a view into both the extremely distant and intrinsically faint galaxy populations. We present here the z ~ 6-8 candidate high-redshift galaxies from the Reionization Lensing Cluster Survey (RELICS), a Hubble and Spitzer Space Telescope survey of 41 massive galaxy clusters spanning an area of ≈200 arcmin². These clusters were selected to be excellent lenses, and we find similar high-redshift sample sizes and magnitude distributions as the Cluster Lensing And Supernova survey with Hubble (CLASH). We discover 257, 57, and eight candidate galaxies at z ~ 6, 7, and 8 respectively, (322 in total). The observed (lensed) magnitudes of the z ~ 6 candidates are as bright as AB mag ~23, making them among the brightest known at these redshifts, comparable with discoveries from much wider, blank-field surveys. RELICS demonstrates the efficiency of using strong gravitational lenses to produce high-redshift samples in the epoch of reionization. These brightly observed galaxies are excellent targets for follow-up study with current and future observatories, including the James Webb Space Telescope
RELICS: Strong Lens Models for Five Galaxy Clusters From the Reionization Lensing Cluster Survey
Strong gravitational lensing by galaxy clusters magnifies background
galaxies, enhancing our ability to discover statistically significant samples
of galaxies at z>6, 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 TelescopesComment: Accepted to Ap
RELICS: High-Resolution Constraints on the Inner Mass Distribution of the z=0.83 Merging Cluster RXJ0152.7-1357 from strong lensing
Strong gravitational lensing (SL) is a powerful means to map the distribution
of dark matter. In this work, we perform a SL analysis of the prominent X-ray
cluster RXJ0152.7-1357 (z=0.83, also known as CL 0152.7-1357) in \textit{Hubble
Space Telescope} images, taken in the framework of the Reionization Lensing
Cluster Survey (RELICS). On top of a previously known galaxy multiply
imaged by RXJ0152.7-1357, for which we identify an additional multiple image,
guided by a light-traces-mass approach we identify seven new sets of multiply
imaged background sources lensed by this cluster, spanning the redshift range
[1.79-3.93]. A total of 25 multiple images are seen over a small area of ~0.4
, allowing us to put relatively high-resolution constraints on the
inner matter distribution. Although modestly massive, the high degree of
substructure together with its very elongated shape make RXJ0152.7-1357 a very
efficient lens for its size. This cluster also comprises the third-largest
sample of z~6-7 candidates in the RELICS survey. Finally, we present a
comparison of our resulting mass distribution and magnification estimates with
those from a Lenstool model. These models are made publicly available through
the MAST archive.Comment: 15 Pages, 7 Figures, 4 Tables Accepted for publication in Ap
RELICS: A Strong Lens Model for SPT-CLJ0615-5746, a z=0.972 Cluster
We present a lens model for the cluster SPT-CLJ06155746, which is the
highest redshift () system in the Reionization of Lensing Clusters
Survey (RELICS), 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 and ,
which we use as constraints for the model. We find a foreground structure at
, 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 (the
region where the strong lensing constraints exist) to be
~M. If we extrapolate out to
, our projected mass density is consistent with the mass inferred from
weak lensing and from the Sunyaev-Zel'dovich effect
(~M). This cluster is lensing a previously reported
galaxy, which, if spectroscopically confirmed, will be the
highest-redshift strongly lensed galaxy known.Comment: 15 pages, 8 figures 4 tables. ApJ Accepte
RELICS: The Reionization Lensing Cluster Survey and the Brightest High-z Galaxies
Massive foreground galaxy clusters magnify and distort the light of objects behind them, permitting a view into both the extremely distant and intrinsically faint galaxy populations. We present here the z ~ 6-8 candidate high-redshift galaxies from the Reionization Lensing Cluster Survey (RELICS), a Hubble and Spitzer Space Telescope survey of 41 massive galaxy clusters spanning an area of ≈200 arcmin². These clusters were selected to be excellent lenses, and we find similar high-redshift sample sizes and magnitude distributions as the Cluster Lensing And Supernova survey with Hubble (CLASH). We discover 257, 57, and eight candidate galaxies at z ~ 6, 7, and 8 respectively, (322 in total). The observed (lensed) magnitudes of the z ~ 6 candidates are as bright as AB mag ~23, making them among the brightest known at these redshifts, comparable with discoveries from much wider, blank-field surveys. RELICS demonstrates the efficiency of using strong gravitational lenses to produce high-redshift samples in the epoch of reionization. These brightly observed galaxies are excellent targets for follow-up study with current and future observatories, including the James Webb Space Telescope
RELICS: A Very Large () Cluster Lens -- RXC J0032.1+1808
Extensive surveys with the \textit{Hubble Space Telescope} (HST) over the
past decade, targeting some of the most massive clusters in the sky, have
uncovered dozens of galaxy-cluster strong lenses. The massive cluster
strong-lens scale is typically \theta_{E}\sim10\arcsec to \sim30-35\arcsec,
with only a handful of clusters known with Einstein radii
\theta_{E}\sim40\arcsec or above (for , nominally). Here we
report another very large cluster lens, RXC J0032.1+1808 (), the
second richest cluster in the redMapper cluster catalog and the 85th most
massive cluster in the Planck Sunyaev-Zel'dovich catalog. With our
Light-Traces-Mass and fully parametric (dPIEeNFW) approaches, we construct
strong lensing models based on 18 multiple images of 5 background galaxies
newly identified in the \textit{Hubble} data mainly from the
\textit{Reionization Lensing Cluster Survey} (RELICS), in addition to a known
sextuply imaged system in this cluster. Furthermore, we compare these models to
Lenstool and GLAFIC models that were produced independently as part of the
RELICS program. All models reveal a large effective Einstein radius of
\theta_{E}\simeq40\arcsec (), owing to the obvious
concentration of substructures near the cluster center. Although RXC
J0032.1+1808 has a very large critical area and high lensing strength, only
three magnified high-redshift candidates are found within the field targeted by
RELICS. Nevertheless, we expect many more high-redshift candidates will be seen
in wider and deeper observations with \textit{Hubble} or \emph{JWST}. Finally,
the comparison between several algorithms demonstrates that the total error
budget is largely dominated by systematic uncertainties.Comment: 23 pages, accepted for publication in Ap
RELICS: Strong Lensing analysis of the galaxy clusters Abell S295, Abell 697, MACS J0025.4-1222, and MACS J0159.8-0849
We present a strong-lensing analysis of four massive galaxy clusters imaged
with the Hubble Space Telescope in the Reionization Lensing Cluster Survey. We
use a Light-Traces-Mass technique to uncover sets of multiply images and
constrain the mass distribution of the clusters. These mass models are the
first published for Abell S295 and MACS J0159.8-0849, and are improvements over
previous models for Abell 697 and MACS J0025.4-1222. Our analysis for MACS
J0025.4-1222 and Abell S295 shows a bimodal mass distribution supporting the
merger scenarios proposed for these clusters. The updated model for MACS
J0025.4-1222 suggests a substantially smaller critical area than previously
estimated. For MACS J0159.8-0849 and Abell 697 we find a single peak and
relatively regular morphology, revealing fairly relaxed clusters. Despite being
less prominent lenses, three of these clusters seem to have lensing strengths,
i.e. cumulative area above certain magnification, similar to the Hubble
Frontier Fields clusters (e.g., A() arcmin, A()
arcmin), which in part can be attributed to their merging
configurations. We make our lens models publicly available through the Mikulski
Archive for Space Telescopes. Finally, using Gemini-N/GMOS spectroscopic
observations we detect a single emission line from a high-redshift
galaxy candidate lensed by Abell 697. While we cannot rule
out a lower-redshift solution, we interpret the line as Ly at
, in agreement with its photometric redshift and dropout
nature. Within this scenario we measure a Ly rest-frame equivalent
width of \AA, and an observed Gaussian width of km/s.Comment: 23 pages, 16 figures; V2, accepted for publication in Ap
RELICS: Reionization Lensing Cluster Survey
Large surveys of galaxy clusters with the Hubble and Spitzer Space
Telescopes, including CLASH and the Frontier Fields, have demonstrated the
power of strong gravitational lensing to efficiently deliver large samples of
high-redshift galaxies. We extend this strategy through a wider, shallower
survey named RELICS, the Reionization Lensing Cluster Survey. This survey,
described here, was designed primarily to deliver the best and brightest
high-redshift candidates from the first billion years after the Big Bang.
RELICS observed 41 massive galaxy clusters with Hubble and Spitzer at 0.4-1.7um
and 3.0-5.0um, respectively. We selected 21 clusters based on Planck PSZ2 mass
estimates and the other 20 based on observed or inferred lensing strength. Our
188-orbit Hubble Treasury Program obtained the first high-resolution
near-infrared images of these clusters to efficiently search for lensed
high-redshift galaxies. We observed 46 WFC3/IR pointings (~200 arcmin^2) with
two orbits divided among four filters (F105W, F125W, F140W, and F160W) and ACS
imaging as needed to achieve single-orbit depth in each of three filters
(F435W, F606W, and F814W). As previously reported by Salmon et al., we
discovered 322 z ~ 6 - 10 candidates, including the brightest known at z ~ 6,
and the most distant spatially-resolved lensed arc known at z ~ 10. Spitzer
IRAC imaging (945 hours awarded, plus 100 archival) has crucially enabled us to
distinguish z ~ 10 candidates from z ~ 2 interlopers. For each cluster, two HST
observing epochs were staggered by about a month, enabling us to discover 11
supernovae, including 3 lensed supernovae, which we followed up with 20 orbits
from our program. We delivered reduced HST images and catalogs of all clusters
to the public via MAST and reduced Spitzer images via IRSA. We have also begun
delivering lens models of all clusters, to be completed before the JWST GO call
for proposals.Comment: 29 pages, 6 figures, submitted to ApJ. For reduced images, catalogs,
lens models, and more, see relics.stsci.ed
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