49 research outputs found
Silverrush. Xii. Intensity Mapping for Ly Α Emission Extending over 100-1000 Comoving Kpc Around Z ∼2-7 Laes with Subaru Hsc-Ssp and Chorus Data
We conduct intensity mapping to probe for extended diffuse Lyα emission around Lyα emitters (LAEs) at z ∼2-7, exploiting very deep (∼26 mag at 5σ) and large-area (∼4.5 deg2) Subaru/Hyper Suprime-Cam narrowband (NB) images and large LAE catalogs consisting of a total of 1540 LAEs at z = 2.2, 3.3, 5.7, and 6.6 obtained by the HSC-SSP and CHORUS projects. We calculate the spatial correlations of these LAEs with ∼1-2-billion-pixel flux values of the NB images, deriving the average Lyα surface brightness (SBLyα ) radial profiles around the LAEs. By carefully estimating systematics such as fluctuations of sky background and point-spread functions, we detect Lyα emission at 100-1000 comoving kpc around z = 3.3 and 5.7 LAEs at the 3.2σ and 3.7σ levels, respectively, and tentatively (=2.0σ) at z = 6.6. The emission is as diffuse as ∼10-20-10-19 erg s-1 cm-2 arcsec-2 and extended beyond the virial radius of a dark matter halo with a mass of 1011 M. While the observed SBLyα profiles have similar amplitudes at z = 2.2-6.6 within the uncertainties, the intrinsic SBLyα profiles (corrected for the cosmological dimming effect) increase toward high redshifts. This trend may be explained by increasing hydrogen gas density due to the evolution of the cosmic volume. Comparisons with theoretical models suggest that extended Lyα emission around an LAE is powered by resonantly scattered Lyα photons in the CGM and IGM that originate from the inner part of the LAE and/or neighboring galaxies around the LAE
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
A Candidate Galaxy Strongly Lensed into a Spatially Resolved Arc
The most distant galaxies known are at z~10-11, observed 400-500 Myr after
the Big Bang. The few z~10-11 candidates discovered to date have been
exceptionally small- barely resolved, if at all, by the Hubble Space Telescope.
Here we present the discovery of SPT0615-JD, a fortuitous z~10
(z_phot=9.9+/-0.6) galaxy candidate stretched into an arc over ~2.5" by the
effects of strong gravitational lensing. Discovered in the Reionization Lensing
Cluster Survey (RELICS) Hubble Treasury program and companion S-RELICS Spitzer
program, this candidate has a lensed H-band magnitude of 25.7+/-0.1 AB mag.
With a magnification of \mu~4-7 estimated from our lens models, the de-lensed
intrinsic magnitude is 27.6+/-0.3 AB mag, and the half-light radius is r_e<0.8
kpc, both consistent with other z>9 candidates. The inferred stellar mass (log
[M* /M_Sun]=9.7^{+0.7}_{-0.5}) and star formation rate (\log [SFR/M_Sun
yr^{-1}]=1.3^{+0.2}_{-0.3}) indicate that this candidate is a typical
star-forming galaxy on the z>6 SFR-M* relation. We note that three independent
lens models predict two counterimages, at least one of which should be of a
similar magnitude to the arc, but these counterimages are not yet detected.
Counterimages would not be expected if the arc were at lower redshift. However,
the only spectral energy distributions capable of fitting the Hubble and
Spitzer photometry well at lower redshifts require unphysical combinations of
z~2 galaxy properties. The unprecedented lensed size of this z~10 candidate
offers the potential for the James Webb Space Telescope to study the geometric
and kinematic properties of a galaxy observed 500 Myr after the Big Bang.Comment: 7 pages, 4 figures. Submitted to ApJ Letter
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: 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
EMPRESS. III. Morphology, Stellar Population, and Dynamics of Extremely Metal Poor Galaxies (EMPGs): Are EMPGs Local Analogs of High- Young Galaxies?
We present the morphology and stellar population of 27 extremely metal poor
galaxies (EMPGs) at with metallicities of 0.01--0.1 Z. We
conduct multi-component surface brightness (SB) profile fitting for the deep
Subaru/HSC -band images of the EMPGs with the {\sc Galfit} software,
carefully removing the SB contributions of tails. We find that the EMPGs with a
median stellar mass of have a median
S{\'e}rsic index of and a median effective radius of
pc, suggesting that typical EMPGs have very compact disk. We compare the EMPGs
with galaxies and local galaxies on the size-mass (-)
diagram, and identify that the majority of the EMPGs have a -
relation similar to star-forming galaxies rather than
galaxies. Not every EMPG is a local analog of high- young galaxies in the
- relation. A spectrum of one pair of EMPG and tail, so far
available, indicates that the tail is dynamically related to the EMPG with a
median velocity difference of km s. This
moderately-large cannot be explained by the dynamics of the tail,
but likely by the infall on the tail. For the first time, we may identify the
metal-poor star-forming system just now infalling into the tail.Comment: ApJ in Pres
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