15 research outputs found
Full Lensing Analysis of Abell 1703: Comparison of Independent Lens-Modelling Techniques
The inner mass-profile of the relaxed cluster Abell 1703 is analysed by two
very different strong-lensing techniques applied to deep ACS and WFC3 imaging.
Our parametric method has the accuracy required to reproduce the many sets of
multiple images, based on the assumption that mass approximately traces light.
We test this assumption with a fully non-parametric, adaptive grid method, with
no knowledge of the galaxy distribution. Differences between the methods are
seen on fine scales due to member galaxies which must be included in models
designed to search for lensed images, but on the larger scale the general
distribution of dark matter is in good agreement, with very similar radial mass
profiles. We add undiluted weak-lensing measurements from deep multi-colour
Subaru imaging to obtain a fully model-independent mass profile out to the
virial radius and beyond. Consistency is found in the region of overlap between
the weak and strong lensing, and the full mass profile is well-described by an
NFW model of a concentration parameter, (and
). Abell 1703 lies above
the standard -- relation predicted for the standard CDM model,
similar to other massive relaxed clusters with accurately determined
lensing-based profiles.Comment: 12 pages, 17 figures, 1 table, accepted for publication in MNRAS. V2
includes minor changes and revised figure
BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1
In this work, we present a constraint on the abundance of supergiant (SG) stars at redshift z ≈ 1, based on recent observations of astrongly lensed arc at this redshift. First we derived a free-form model of MACS J0416.1-2403 using data from the Beyond Ultradeep Frontier Fields and Legacy Observations (BUFFALO) program. The new lens model is based on 72 multiply lensed galaxies thatproduce 214 multiple images, making it the largest sample of spectroscopically confirmed lensed galaxies on this cluster. The largercoverage in BUFFALO allowed us to measure the shear up to the outskirts of the cluster, and extend the range of lensing constraintsup to ∼1 Mpc from the central region, providing a mass estimate up to this radius. As an application, we make predictions for thenumber of high-redshift multiply lensed galaxies detected in future observations with the James Webb Space Telescope (JWST).Then we focus on a previously known lensed galaxy at z = 1.0054, nicknamed Spock, which contains four previously reportedtransients. We interpret these transients as microcaustic crossings of SG stars and explain how we computed the probability of suchevents. Based on simplifications regarding the stellar evolution, we find that microlensing (by stars in the intracluster medium) ofSG stars at z = 1.0054 can fully explain these events. The inferred abundance of SG stars is consistent with either (1) a numberdensity of stars with bolometric luminosities beyond the Humphreys-Davidson (HD) limit (Lmax ≈ 6 × 105 L for red stars), whichis below ∼400 stars kpc−2, or (2) the absence of stars beyond the HD limit but with a SG number density of ∼9000 kpc−2 for starswith luminosities between 105 L and 6 × 105 L. This is equivalent to one SG star per 10 × 10 pc2. Finally, we make predictions forfuture observations with JWST’s NIRcam. We find that in observations made with the F200W filter that reach 29 mag AB, if cool red SG stars exist at z ≈ 1 beyond the HD limit, they should be easily detected in this arc
BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1
We present a constraint on the abundance of supergiant (SG) stars at redshift
z approx. 1, based on recent observations of a strongly lensed arc at this
redshift. First we derive a free-form model of MACS J0416.1-2403 using data
from the BUFFALO program. The new lens model is based on 72 multiply lensed
galaxies that produce 214 multiple images, making it the largest sample of
spectroscopically confirmed lensed galaxies on this cluster. The larger
coverage in BUFFALO allows us to measure the shear up to the outskirts of the
cluster, and extend the range of lensing constraints up to ~ 1 Mpc from the
central region, providing a mass estimate up to this radius. As an application,
we make predictions for the number of high-redshift multiply-lensed galaxies
detected in future observations with JWST. Then we focus on a previously known
lensed galaxy at z=1.0054, nicknamed Spock, which contains four previously
reported transients. We interpret these transients as microcaustic crossings of
SG stars and compute the probability of such events. Based on simplifications
regarding the stellar evolution, we find that microlensing (by stars in the
intracluster medium) of SG stars at z=1.0054 can fully explain these events.
The inferred abundance of SG stars is consistent with either (1) a number
density of stars with bolometric luminosities beyond the Humphreys-Davidson
(HD) limit (L ~ ) that is below 400 stars per sq. kpc,
or (2) the absence of stars beyond the HD limit but with a SG number density of
~ 9000 per sq. kpc for stars with luminosities between and
. This is equivalent to one SG star per 10x10 pc. We finally
make predictions for future observations with JWST's NIRcam. We find that in
observations made with the F200W filter that reach 29 mag AB, if cool red SG
stars exist at z~1 beyond the HD limit, they should be easily detected in this
arcComment: 24 pages & 18 figure
Delivery of SAR 1118 to the Retina via Ophthalmic Drops and its Effectiveness in a Rat Streptozotocin (STZ) Model of Diabetic Retinopathy (DR)
The delivery and efficacy of SAR 1118 were examined in a rat model of diabetic retinopathy
BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1
International audienceWe present a constraint on the abundance of supergiant (SG) stars at redshift z approx. 1, based on recent observations of a strongly lensed arc at this redshift. First we derive a free-form model of MACS J0416.1-2403 using data from the BUFFALO program. The new lens model is based on 72 multiply lensed galaxies that produce 214 multiple images, making it the largest sample of spectroscopically confirmed lensed galaxies on this cluster. The larger coverage in BUFFALO allows us to measure the shear up to the outskirts of the cluster, and extend the range of lensing constraints up to ~ 1 Mpc from the central region, providing a mass estimate up to this radius. As an application, we make predictions for the number of high-redshift multiply-lensed galaxies detected in future observations with JWST. Then we focus on a previously known lensed galaxy at z=1.0054, nicknamed Spock, which contains four previously reported transients. We interpret these transients as microcaustic crossings of SG stars and compute the probability of such events. Based on simplifications regarding the stellar evolution, we find that microlensing (by stars in the intracluster medium) of SG stars at z=1.0054 can fully explain these events. The inferred abundance of SG stars is consistent with either (1) a number density of stars with bolometric luminosities beyond the Humphreys-Davidson (HD) limit (L ~) that is below 400 stars per sq. kpc, or (2) the absence of stars beyond the HD limit but with a SG number density of ~ 9000 per sq. kpc for stars with luminosities between and . This is equivalent to one SG star per 10x10 pc. We finally make predictions for future observations with JWST's NIRcam. We find that in observations made with the F200W filter that reach 29 mag AB, if cool red SG stars exist at z~1 beyond the HD limit, they should be easily detected in this ar
BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1
International audienceWe present a constraint on the abundance of supergiant (SG) stars at redshift z approx. 1, based on recent observations of a strongly lensed arc at this redshift. First we derive a free-form model of MACS J0416.1-2403 using data from the BUFFALO program. The new lens model is based on 72 multiply lensed galaxies that produce 214 multiple images, making it the largest sample of spectroscopically confirmed lensed galaxies on this cluster. The larger coverage in BUFFALO allows us to measure the shear up to the outskirts of the cluster, and extend the range of lensing constraints up to ~ 1 Mpc from the central region, providing a mass estimate up to this radius. As an application, we make predictions for the number of high-redshift multiply-lensed galaxies detected in future observations with JWST. Then we focus on a previously known lensed galaxy at z=1.0054, nicknamed Spock, which contains four previously reported transients. We interpret these transients as microcaustic crossings of SG stars and compute the probability of such events. Based on simplifications regarding the stellar evolution, we find that microlensing (by stars in the intracluster medium) of SG stars at z=1.0054 can fully explain these events. The inferred abundance of SG stars is consistent with either (1) a number density of stars with bolometric luminosities beyond the Humphreys-Davidson (HD) limit (L ~) that is below 400 stars per sq. kpc, or (2) the absence of stars beyond the HD limit but with a SG number density of ~ 9000 per sq. kpc for stars with luminosities between and . This is equivalent to one SG star per 10x10 pc. We finally make predictions for future observations with JWST's NIRcam. We find that in observations made with the F200W filter that reach 29 mag AB, if cool red SG stars exist at z~1 beyond the HD limit, they should be easily detected in this ar