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Responsive coaching at engage2learn is an innovative, and with this and previous reports--an evidence-based solution. This 2021-2022 study compellingly validates the efficacy of the engage2learn program through an exploration of NWEA MAP® Growth™ and STAAR test scores for Math and Science, Grades 6-8. LXD Research, an independent research firm, analyzed educator achievement through the life of the engage2learn partnership with a large urban school district in Texas. This report focuses on student growth on benchmark assessments (over 2,000 students in total) during the 2021-2022 school year and evaluates the relationship between educator engage2Learn participation and student growth, along with differences in school climate. The robust sample, 169 teachers across 10 schools, showed that the impact of teacher participation in engage2Learn on student academic growth is positive and significant in both math and science.

A quadruply lensed source, J125856.3-031944, has been discovered using the DELVE survey and WISE W1 - W2 colors. Followup direct imaging carried out with the MPIA 2.2 m and the Baade 6.5 m telescopes is analyzed, as is spectroscopy from the 2.5 m Nordic Optical Telescope. The lensed image configuration is kite-like, with the faintest image 2 magnitudes fainter than the other three. Redward of 6000 AA that image is badly blended with the lensing galaxy, which is elongated along the symmetry axis of the kite. Magellan direct imaging carried out in Sloan g permits better deblending. As the lensed image configuration is nearly circular, simple models give individual magnifications of at least 25 for the 3 brighter images. The source's narrow emission lines and low intrinsic luminosity qualify it as a type 2 AGN., Comment: 8 pages, 5 figures, submitted to AJ, comments welcome

Microlensing near macro-caustics is a complex phenomenon in which swarms of micro-images produced by micro-caustics form on both sides of a macro-critical curve. Recent discoveries of highly magnified images of individual stars in massive galaxy cluster lenses, predicted to be formed by these micro-image swarms, have stimulated studies on this topic. In this Chapter, we explore microlensing near macro-caustics using both simulations and analytic calculations. We show that the mean total magnification of the micro-image swarms follows that of an extended source in the absence of microlensing. Micro-caustics join into a connected network in a region around the macro-critical line of a width proportional to the surface density of microlenses; within this region, the increase of the mean magnification toward the macro-caustic is driven by the increase of the number of micro-images rather than individual magnifications of micro-images. The maximum achievable magnification in micro-caustic crossings decreases with the mass fraction in microlenses. We conclude with a review of applications of this microlensing phenomenon, including limits to the fraction of dark matter in compact objects, and searches of Population III stars and dark matter subhalos. We argue that the discovered highly magnified stars at cosmological distances already imply that less than $\sim$ 10\% of the dark matter may be in the form of compact objects with mass above $\sim 10^{-6}\, M_{\odot}$., Comment: 9 pages, 6 figures; to be submitted to Space Science Reviews, Topical Collection "Strong Gravitational Lensing", eds. J. Wambsganss et al

When a rectangular hyperbola is constructed from the image positions of a quadruply lensed quasar, as proposed by Witt (1996), it passes very close to the the lensing galaxy. The median measured perpendicular offset between the observed light center of the lens and Witt's hyperbola is 0.013" for a sample for 39 systems lensed by a relatively isolated galaxy. The family of lens models adopted by Witt predicts that the lens lies on the hyperbola, but its position in not used for its construction. The median offset corresponds to roughly 1% of the Einstein ring radius, and suggests that the centers of the lensing potential are close to the light centers of the lens. By putting a restrictive prior on the perpendicular distance to Witt's hyperbola (or on the distance between the galaxy and the potential), one reduces by one the dimensionality of a model space when fitting data. Taking the brightest pixel of a lensing galaxy as its center avoids a shortcoming of using the average light center for a constraint., Comment: 10 pages. Refereed, re-imagined, re-titled and re-submitted to ApJ

EPS contracted with LXD Research, a third-party research company, to examine the relationship between progress in S.P.I.R.E. and student reading outcomes at Martin County School District in Florida. LXD Research analyzed 192 students from grades 3-5 in 13 elementary schools who use S.P.I.R.E./i.S.P.I.R.E. reading intervention that uses an Orton-Gillingham approach. The Martin County School District's largest racial/ethnic group is Hispanic (48%), and over one-third of students (38%) had a Limited English Proficiency class or were still being monitored. Researchers used S.P.I.R.E. progress level and the Florida Assessment of Student Thinking (FAST) to understand the impact of the intervention program on student's learning outcomes. LXD Research found that students who completed more lessons in S.P.I.R.E. had higher literacy achievement at the end of the study, and these relationships were statistically significant. For all grades, students who completed more S.P.I.R.E. levels had higher spring FAST achievement (t(190) = 2.9, p < 0.01, Cohen's d effect size = 0.44). For all grades, S.P.I.R.E. ending level was significantly correlated with spring FAST achievement (r(190) = 0.43, p < 0.01) for students in Grades 3-5. After controlling for grade, race, LEP status, gender, and Fall FAST scores in an Analysis of Covariance, S.P.I.R.E. significantly predicted spring FAST achievement for students across Grades 3-5. This study provides results to satisfy ESSA evidence requirements for Level III (Promising Evidence) given the study design and positive, statistically significant findings.

This study aims to measure the impact of 95 Percent Group's Phonological Awareness Lessons (PA Lessons), an intervention program designed primarily for Tier 2 or 3. The study is a replication of Schechter & Lynch (2023) research conducted in the same medium-sized school district, Val Verde Unified School District, in California during the 2021-2022 school year. It presents the fall results from September 2022 to January 2023 using Acadience? Reading data. The same school groups (treatment with PA Lessons and comparison without the PA Lessons) continue from the previous study and therefore uses a quasi-experimental design to generate evidence of the program's impact that aligns with evidence standards associated with ESSA Level 2 (Moderate). A total of 527 kindergarten students from 11 schools who were well below/below benchmark in the Fall of 2022 participated in the study. Of these students, 257 were in the treatment group, and 270 were in the comparison group. The demographic characteristics of the comparison group included 56% males, 3% with special education (SPED) status, 44% English Language Learners (ELL), 88% from diverse ethnic/racial backgrounds, and 24% identified as foster/homeless. Similarly, the treatment group demographics comprise 51% males, 2% with SPED status, 36% ELL, 87% from diverse ethnic/racial backgrounds, and 20% identified as foster/homeless. Results of the study found that using PA Lessons substantially impacted student growth for Tiers 2 & 3 over the fall. PA Lesson schools had reduced Well Below Grade Level by half (67% to 28%). Comparison schools only reduced the group by less than a third (67% to 47%). Notably, 41% of PA Lesson students were At/Above grade level mid-year, compared to only 25% in other schools.

This study measures the impact of 95 Percent Group's Phonological Awareness Lessons (PA Lessons), an intervention program designed for kindergartners for Tier 2 or 3. The study is a replication of a study conducted in the same medium-sized school district in California during 2021-2022. Students Below or Well Below Benchmark in Fall 2022 were assessed with Acadience? Reading was used to compare literacy growth from 2022-2023 using a quasi-experimental design, aligning with Moderate evidence standards associated with ESSA Level. The study follows 536 kindergarten students from 11 schools, 260 in the treatment group, and 276 in the comparison group. The demographic characteristics of the comparison group included 56% males, 3% with special education (SPED) status, 45% English Language Learners (ELL), 88% were Hispanic, and 24% identified as foster/homeless. Similarly, the treatment group demographics comprise 51% males, 2% with SPED status, 36% ELL, 87% were Hispanic, and 21% identified as foster/homeless. Results showed that using PA Lessons substantially impacted student growth for Tiers 2 & 3 across the school year with a Cohen's d effect size .84, which is more than twice as large as previous studies. PA Lesson schools reduced Well Below Grade Level by 25 percentage points from Fall to Spring (72% to 47%). Alternatively, comparison schools only reduced the group by 20 percentage points from Fall to Spring (79% to 59%). Notably, an additional 10% of students ended the year At or Above Benchmark for the grade level (36% PA Lessons vs. 26% Other Schools).

LXD Research analyzed data from 405 students from kindergarten through first grade who either participated in using the 95 Phonics Core Program (95PCP) or served as comparison students in a school district in AZ during the school year 2022-2023. This product adds explicit and systematic phonics instruction to the daily reading block. The demographic breakdown of this sample includes 27% Indigenous students, 40% Hispanic students, 46% Low Income, 13% Special Education students, and 12% Limited English Proficient students. Two schools volunteered to use 95PCP as their core reading curriculum and used it for about 30 minutes a day. Three comparison schools with similar demographics and literacy scores created a matched sample and used National Geographic (NatGeo) as their core reading program. The Aimsweb Plus Reading Early Literacy Assessment was conducted at the beginning, middle, and end of year 2023 to understand the programs' impact on reading. Students using 95PCP showed significantly more reading growth on the Aimsweb assessment compared to the comparison group. Kindergarten students using 95PCP scored 17 more points than the comparison group on their early literacy scores at the end of the year and first grade students scored 8 more points than the comparison group at the end of the year. Notably, the impact of 95PCP led to an additional 22% of kindergartners and 8% of first graders to being on track, considered "Low Risk" on Aimsweb, in the Spring 2023. The findings and rigorous study design support the 95 Phonics Core Program as a comprehensive program that meets the criteria for ESSA Level 2.

This study explores the efficacy of core phonics and intervention products by 95 Percent Group, LLC ("One95"), drawing on the relationship between technology, the science of reading, and learning sciences. Researchers analyzed data from 440 K-1 students in Maryland that rolled out One95 over two school years, fall 2020 to spring 2022. The sample included students who were 54% Black, 15% ELL, 8% SPED, and 75% Economically Disadvantaged. According to iReady® Diagnostic Reading, One95 students outperformed similar students who did not receive the program in the first year. In the second year, both groups used One95, and students with two years of use showed earlier growth and doubled the effect sizes than those with one year of use (0.64 vs. 0.31). Black One95 students also showed stronger reading outcomes than their comparison group peers by spring 2022. These results support that One95 positively and significantly impacted student literacy achievement.

With two central galaxies engaged in a major merger and a remarkable chain of 19 young stellar superclusters wound around them in projection, the galaxy cluster SDSS J1531+3414 ($z=0.335$) offers an excellent laboratory to study the interplay between mergers, AGN feedback, and star formation. New Chandra X-ray imaging reveals rapidly cooling hot ($T\sim 10^6$ K) intracluster gas, with two "wings" forming a concave density discontinuity near the edge of the cool core. LOFAR $144$ MHz observations uncover diffuse radio emission strikingly aligned with the "wings," suggesting that the "wings" are actually the opening to a giant X-ray supercavity. The steep radio emission is likely an ancient relic of one of the most energetic AGN outbursts observed, with $4pV > 10^{61}$ erg. To the north of the supercavity, GMOS detects warm ($T\sim 10^4$ K) ionized gas that enshrouds the stellar superclusters but is redshifted up to $+ 800$ km s$^{-1}$ with respect to the southern central galaxy. ALMA detects a similarly redshifted $\sim 10^{10}$ M$_\odot$ reservoir of cold ($T\sim 10^2$ K) molecular gas, but it is offset from the young stars by $\sim 1{-}3$ kpc. We propose that the multiphase gas originated from low-entropy gas entrained by the X-ray supercavity, attribute the offset between the young stars and the molecular gas to turbulent intracluster gas motions, and suggest that tidal interactions stimulated the "beads on a string" star formation morphology., Comment: Accepted by ApJ, 36 pages, 23 figures

Strong gravitational lensing of quasars has the potential to unlock the poorly understood physics of these fascinating objects, as well as serve as a probe of the lensing mass distribution and of cosmological parameters. In particular, gravitational microlensing by compact bodies in the lensing galaxy can enable mapping of quasar structure to $\lt 10^{-6}$ arcsec scales. Some of this potential has been realized over the past few decades, however the upcoming era of large sky surveys promises to bring this to full fruition. Here we review the theoretical framework of this field, describe the prominent current methods for parameter inference from quasar microlensing data across different observing modalities, and discuss the constraints so far derived on the geometry and physics of quasar inner structure. We also review the application of strong lensing and microlensing to constraining the granularity of the lens potential, i.e. the contribution of the baryonic and dark matter components, and the local mass distribution in the lens, i.e. the stellar mass function. Finally, we discuss the future of the field, including the new possibilities that will be opened by the next generation of large surveys and by new analysis methods now being developed., Comment: To be submitted to Space Science Reviews, Topical Collection "Strong Gravitational Lensing", eds. J. Wambsganss et al

LXD Research analyzed data from 945 students in kindergarten who were Below or Well Below Benchmark at the beginning of the year and participated in using the Phonological Awareness (PA) Lessons Deluxe Package as an intervention in CA in Fall 2021. The product is a Tier 2 or Tier 3 intervention for grades K-2 that includes lessons and manipulatives that focuses on explicit and systematic instruction to advance skill development along the Phonological Awareness Continuum. Within the sample, 79% of students were Hispanic, 28% were ELL, and 15% were Foster or Homeless. Students using the PA Lessons during targeted, small group, 20-30-minute daily interventions showed higher gains on Acadience Reading than the comparison group. The significance of the findings and the rigorous study design provide support for Phonological Awareness Lessons Deluxe Package as a program that meets the criteria for ESSA Level 2. [This report was produced by Learning Experience Design (LXD) Research & Consulting and 95 Percent Group LLC.]

LXD Research analyzed data from 462 students in first grade who were Below or Well Below Benchmark at the beginning of the year and participated in using the Phonics Lesson Library and the Phonics Chip Kit as an intervention in CA for the 2021-2022 school year. The product is a Tier 2 or Tier 3 phonics intervention using lessons and manipulatives that support skill development along the Phonics Continuum. The demographic breakdown of this sample included 82% Hispanic students, 33% ELL students, 4% SPED students, and 5% Foster or Homeless students. Students using the Phonics Lesson Library and Phonics Chip Kit during targeted, small group, 30-minute daily explicit and systematic phonics instruction showed higher gains on the CORE Phonics Survey and Acadience Reading than the comparison group. The significance of the findings and the rigorous study design support the Phonics Lesson Library and Phonics Chip Kit as programs that meet the criteria for ESSA Level 2.

The engage2learn approach to educator support provides an in-person and virtual coaching system that builds capacity and engagement in public schools. Engage2learn hired LXD Research to conduct an independent evaluation and analysis of NWEA Math and Reading data collected during the 2021-2022 school year. The goal was to measure how engage2learn contributed to the faculty's shared and growing use of instructional best practices in the classroom and if those best practices impacted student outcomes. Engage2learn created a partnership with a midsize urban school district comprised of over 15K+ students (46% Hispanic) located in Texas. The sample encompasses 14 schools, 309 teachers, and over 4,000 students, spanning Reading and Math content areas and across grade levels (K-5). 209 teachers and 5,369 students were assigned to use engage2learn, and 123 teachers (2, 877 students) were included as a statistically similar comparison who did not use engage2learn. The school district provided LXD Research with NWEA MAP scores for all students during the 2021-2022 school year. The results showed that the impact of teacher mastery on student academic growth is positive and significant in reading and math. Students of teachers who earned multiple Mastery Badges (4 or more) had significantly higher growth in Reading and Math MAP RIT Score gains than students of teachers who earned No Mastery Badges. Students of teachers who earned multiple Mastery Badges were also significantly more likely to meet reading and math growth targets than teachers who earned No Mastery Badges. Educators who earned four or more Mastery Badges further increased student likelihood to achieve their reading and math growth targets (60%) compared to teachers who earned No Mastery Badges (38% reading, 33% math). The findings are compelling due to the consistency of significant results across multiple grades and subject areas. The impact and findings are relevant for diverse stakeholder groups, including those who care primarily about student achievement and those who believe in or are curious about the connection between strong and innovative teacher coaching and student outcomes. The findings indicate that engage2learn is a powerful tool for schools to support educators and their students. There is an opportunity for the addition of educator voices in future studies that will offer feedback about implementation and engagement to add insight to the assessment data and allow for the research to inform the ongoing product design, development, and iteration.

Strongly lensed systems with peculiar configurations allow us to probe the local properties of the deflecting lens mass while simultaneously testing general profile assumptions. The quasar HE0230$-$2130 is lensed by two galaxies at similar redshifts ($\Delta z \sim 0.003$) into four observed images. Using modeled quasar positions from fitting the brightness of the quasar images in ground-based imaging data from the Magellan telescope, we find that lens-mass models where each of these two galaxies is parametrized with a singular power-law (PL) profile predict five quasar images. To interpret the quad configuration of the system, we tested 12 different profile assumptions with the aim of obtaining lens-mass models that correctly predict only four observed images. We tested the effects of adopting: cored profiles for the lensing galaxies; external shear; and additional profiles to represent a dark matter clump. We find that half of our model classes can produce the correct image multiplicity. By comparing the Bayesian evidence of different model parametrizations, we favor two model classes: (i) one that incorporates two singular PL profiles for the lensing galaxies and a cored isothermal sphere in the region of the previously predicted fifth image (rNIS profile), and (ii) one with a bigger lensing galaxy parametrized by a singular PL profile and the smaller galaxy by a cored PL profile with external shear. We estimated the mass of the rNIS clump for each candidate model of our final Markov chain Monte Carlo sample, and find that only 2\% are in the range of $10^6 M_{\odot} \leq M_{\rm rNIS}\leq 10^9 M_{\odot}$, which is the predicted mass range of dark matter subhalos in cold dark matter simulations, or the mass of dark-matter-dominated and low-surface-brightness galaxies. We therefore favor the models with a cored mass distribution for the lens galaxy close to the predicted fifth image., Comment: 22 pages, 13 figures, 7 tables; accepted by A&A

LXD Research analyzed data from over 3,200 students in grades K-2 who participated in using the 95 Phonics Core Program in a school district in MO during 2021-2022. The demographic breakdown of this sample included 75% White students, 23% Low Income students, 9% ESL students, 13% SPED students. Schools in the district were paired for similar ELA scores in Spring 2021, and then randomly assigned to treatment or control groups. Students in the 95 Phonics Core Program used the program every day for about 30 minutes during the daily reading block and teachers received the beginning of the year training with two question-answer sessions every few months. 95PCP schools outperformed students in the control group schools who did not receive the 95 Phonics Core Program, according to the Acadience Reading assessment. Students in each grade K-2 had statistically significant findings on either the composite score or a subtest score. The findings and rigorous study design provide support for the 95 Phonics Core Program as a comprehensive program that meets the criteria for ESSA Level 1. [95 Percent Group partnered with LXD Research to conduct this evaluation.]

We identify the first quiescent galaxies in TNG300, the largest volume of the IllustrisTNG cosmological simulation suite, and explore their quenching processes and time evolution to z=0. We find that the first quiescent galaxies with stellar masses M_* > 3 x 10^{10} M_sun and specific star formation rates sSFR < 10^{-11} yr^{-1} emerge at z~4.2 in TNG300. Suppression of star formation in these galaxies begins with a thermal mode of AGN feedback at z~6, and a kinetic feedback mode acts in each galaxy by z~4.7 to complete the quenching process, which occurs on a time-scale of ~0.35 Gyr. Surprisingly, we find that the majority of these galaxies are not the main progenitors of their z=0 descendants; instead, four of the five galaxies fall into more massive galaxies in subsequent mergers at a range of redshifts 2.5 < z < 0.2. By z=0, these descendants are the centres of galaxy clusters with average stellar masses of 8 x 10^{11} M_sun. We make predictions for the first quenched galaxies to be located by the James Webb Space Telescope (JWST)., Comment: 6 pages, 4 figures

While teaching summer school may require similar skills as reading intervention during the year, rarely are summer school instructors reading specialists. To support these instructors providing high quality instruction, this research study examined the impact of the 95 Phonics Booster Bundle: Summer School Edition (SSE). The SSE is a set of 25 fully-scripted lessons with HTML presentation files designed to quickly bolster phonics skills that had been covered in the previous school year. 95 Percent Group hired LXD Research to conduct an independent evaluation of the SSE. LXD Research designed a quasi-experimental study to determine the ability of SSE to support literacy skill development over the summer months. The Acadience Reading assessment was administered to assess student outcomes (testing occurred in the Spring and Fall). Study 1 used one SSE lesson a day over six weeks, and Study 2 intensively used two SSE lessons a day over one month. LXD Research collected data from 958 students in grades 1-3 to determine the efficacy of the 95 Phonics Booster Bundle SSE product. 479 students were assigned to use SSE and 479 were included as statistically similar comparison students who did not use SSE. The study was conducted in Summer 2021, and spanned two school districts, one in California (63% Hispanic) and one in Arizona (46% Hispanic). Rising first graders who completed one SSE lesson a day across six weeks outperformed similar students who did not attend summer school, according to the Acadience Reading assessment, where SSE students showed an 8-point gain compared to a 6-point slide. For rising third graders who were Well Below Benchmark, students who completed two SSE lessons a day for one month outperformed non-SSE students on Acadience Reading, showing a 16-point gain compared to a 4-point slide. Results for other groups were comparable to the comparison students. The significance of the findings and the rigorous study design provide support for 95 Phonics Booster Bundle SSE as a program that meets the criteria for ESSA Level 2. The findings indicate that the 95 Phonics Booster Bundle SSE is a powerful tool for schools to use to support early literacy and reading development. [This report was produced by LXD Research and 95 Percent Group.]

A simple, novice-friendly scheme for classifying the image configurations of quadruply lensed quasars is proposed. With only six classes, it is intentionally coarse-grained. It focuses on the kitelikeness and circularity of these configurations, or the absence thereof. Other features are deliberately ignored, their importance to professional astronomers notwithstanding. Readers are invited to test drive the scheme on a sample of 12 quadruply lensed quasar systems. The theoretical underpinnings of the scheme are described in a technical appendix., Comment: Revised at referee's suggestion. Theoretical considerations relegated to an appendix. Includes new figure

The quadruple image configurations of gravitational lenses with vanishing ellipticity are examined. Even though such lenses asymptotically approach circularity, the configurations are stable if the position of the source relative to the vanishing diamond caustic is held constant. The configurations are the solutions of a quartic equation, an "Asymptotically Circular Lens Equation" (ACLE), parameterized by a single complex quantity. Several alternative parameterizations are examined. Relative magnifications of the images are derived. When a non-vanishing quadrupole, in the form of an external shear (XS), is added to the singular isothermal sphere (SIS), its configurations emerge naturally as stretched and squeezed versions of the circular configurations. And as the SIS+XS model is a good first approximation for most quadruply lensed quasars, their configurations likewise have only 2+1 salient dimensions. The asymptotically circular configurations can easily be adapted to the problem of Solar System "occultation flashes.", Comment: Submitted to ApJ. 25 pages, 10 figures of which Figure 8 is the one to remember

We present the Strong Lensing Science Collaboration's (SLSC) recommended observing targets for the science verification and science validation phases of commissioning. Our recommendations have been developed in collaboration with the Dark Energy Science Collaboration (DESC) Strong Lensing Topical Team. In summary, our key recommendations are as follows: (1) Prioritize fields that span the full range of declination observable from Cerro Pachon during the engineering focused Science Verification phase of commissioning, before concentrating on equatorial fields for the Science Validation surveys. (2) Observe quadruply lensed quasars as the ultimate test of the Active Optics system towards the end of the Science Verification phase of commissioning. These systems are the strongest tests known for delivered image quality. (3) Prioritize science validation survey fields (both single deep pointings and wide fields) that have been searched thoroughly by precursor surveys for strong lenses. (4) The optimal wide (~100 degree^2) science validation field would include the CFHT-LS W4 field, and overlap with the SDSS Stripe 82, DES-SN, KIDS and HSC-SSP fields. (5) The optimal single pointing science validation fields are the XMM-LSS and COSMOS Deep Drilling Fields, the equatorial Hubble Frontier Fields galaxy clusters, and strongly lensed quasars with measured time delays that are well-matched to commissioning timescales., Comment: 8 pages, 1 figure

Quasars are quadruply lensed only when they lie within the diamond caustic of a lensing galaxy. This precondition produces a Malmquist-like selection effect in observed populations of quadruply lensed quasars, overestimating the true caustic area. The bias toward high values of the inferred logarithmic area, $\ln A_{inf}$, is proportional to the square of the error in that area, $\sigma^2_{\ln{A}}$. In effect, Malmquist's correction compensates post-hoc for a failure to incorporate a prior into parameter optimization. Inferred time delays are proportional to the square root of the inferred caustic area of the lensing galaxy. Model time delays are biased long, leading to overestimates of the Hubble constant. Crude estimates of $\sigma_{\ln A}$ for a sample of 13 quadruple systems give a median value of 0.16. We identify a second effect, "inferred magnification bias,'' resulting from the combination of selection by apparent magnitude and errors in model magnification. It is strongly anti-correlated with caustic area bias, and almost always leads to underestimates of the Hubble constant. Malmquist's scheme can be adapted to priors on multiple parameters, but for quad lenses, the negative covariances between caustic area and absolute magnitude are poorly known. Inferred magnification bias may even cancel out caustic area bias, depending upon (among other things) the slope of the number magnitude relation for the sample. Proper correction for these combined effects can, in principle, be built into Bayesian modeling schemes as priors, eliminating the need for Malmquist-style approximation, but is likely to be challenging in practice., Comment: 13 pages, 2 figures, as accepted by ApJ. Addresses referee's assertion that Monte Carlo methods automatically correct for caustic area bias

Among known strongly lensed quasar systems, ~25% have gravitational potentials sufficiently flat (and sources sufficiently well aligned) to produce four images rather than two. The projected flattening of the lensing galaxy and tides from neighboring galaxies both contribute to the potential's quadrupole. Witt's hyperbola and Wynne's ellipse permit determination of the overall quadrupole from the positions of the quasar images. The position of the lensing galaxy resolves the distinct contributions of intrinsic ellipticity and tidal shear to that quadrupole. Among 31 quadruply lensed quasars systems with statistically significant decompositions, 15 are either reliably ($2\sigma$) or provisionally ($1\sigma$) shear-dominated and 11 are either reliably or provisionally ellipticity-dominated. For the remaining 8, the two effects make roughly equal contributions to the combined cross section (newly derived here) for quadruple lensing. This observational result is strongly at variance with the ellipticity-dominated forecast of Oguri & Marshall (2010)., Comment: AASTeX v6.3, 13 pages with 2 figures, revised with expanded discussion of magnification bias. Accepted for publication in ApJ

We report upon three years of follow-up and confirmation of doubly imaged quasar lenses through imaging campaigns from 2016-2018 with the Near-Infrared Camera2 (NIRC2) on the W. M. Keck Observatory. A sample of 57 quasar lens candidates are imaged in adaptive-optics-assisted or seeing-limited $K^\prime$-band observations. Out of these 57 candidates, 15 are confirmed as lenses. We form a sample of 20 lenses adding in a number of previously-known lenses that were imaged with NIRC2 in 2013-14 as part of a pilot study. By modelling these 20 lenses, we obtain $K^\prime$-band relative photometry and astrometry of the quasar images and the lens galaxy. We also provide the lens properties and predicted time delays to aid planning of follow-up observations necessary for various astrophysical applications, e.g., spectroscopic follow-up to obtain the deflector redshifts for the newly confirmed systems. We compare the departure of the observed flux ratios from the smooth-model predictions between doubly and quadruply imaged quasar systems. We find that the departure is consistent between these two types of lenses if the modelling uncertainty is comparable., Comment: 11 pages, 8 figures, 5 tables. This version: accepted to MNRAS

We present spectroscopic confirmation of three new two-image gravitationally lensed quasars, compiled from existing strong lens and X-ray catalogs. Images of HSC J091843.27$-$022007.5 show a red galaxy with two blue point sources at either side, separated by 2.26 arcsec. This system has a source and a lens redshifts $z_s=0.804$ and $z_{\ell}=0.459$, respectively, as obtained by our follow-up spectroscopic data. CXCO J100201.50$+$020330.0 shows two point sources separated by 0.85 arcsec on either side of an early-type galaxy. The follow-up spectroscopic data confirm the fainter quasar has the same redshift with the brighter quasar from the SDSS fiber spectrum at $z_s=2.016$. The deflecting foreground galaxy is a typical early-type galaxy at a redshift of $z_{\ell}=0.439$. SDSS J135944.21$+$012809.8 has two point sources with quasar spectra at the same redshift $z_s=1.096$, separated by 1.05 arcsec, and fits to the HSC images confirm the presence of a galaxy between these. These discoveries demonstrate the power of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP)'s deep imaging and wide sky coverage. Combined with existing X-ray source catalogues and follow-up spectroscopy, the HSC-SSP provides us unique opportunities to find multiple-image quasars lensed by a foreground galaxy., Comment: Accepted for publication in MNRAS, 7 pages, 3 figures (add credit to Claude Cornen)

We report the results of the STRong lensing Insights from the Dark Energy Survey (STRIDES) follow-up campaign of the late 2017/early 2018 season. We obtained spectra of 65 lensed quasar candidates either with EFOSC2 on the NTT or ESI on Keck, which confirm 10 new gravitationally lensed quasars and 10 quasar pairs with similar spectra, but which do not show a lensing galaxy in DES images. Eight lensed quasars are doubly imaged with source redshifts between 0.99 and 2.90, one is triply imaged by a group (DESJ0345-2545, $z=1.68$), and one is quadruply imaged (quad: DESJ0053-2012, $z=3.8$). Singular isothermal ellipsoid models for the doubles, based on high-resolution imaging from SAMI on SOAR or NIRC2 on Keck, give total magnifications between 3.2 and 5.6, and Einstein radii between 0.49 and 1.97 arcseconds. After spectroscopic follow-up, we extract multi-epoch $grizY$ photometry of confirmed lensed quasars and contaminant quasar+star pairs from the first 4 years of DES data using parametric multi-band modelling, and compare variability in each system's components. By measuring the reduced ${\chi}^2$ associated with fitting all epochs to the same magnitude, we find a simple cut on the less variable component that retains all confirmed lensed quasars, while removing 94 per cent of contaminant systems with stellar components. Based on our spectroscopic follow-up, this variability information can improve selection of lensed quasars and quasar pairs from 34-45 per cent to 51-70 per cent, with the majority of remaining contaminants being compact star-forming galaxies. Using mock lensed quasar lightcurves we demonstrate that selection based only on variability will over-represent the quad fraction by 10 per cent over a complete DES magnitude-limited sample (excluding microlensing differences), explained by the magnification bias and hence lower luminosity (more variable) sources in quads., Comment: 22 pages, 16 figures, submitted to MNRAS

Witt (1996) has shown that for an elliptical potential, the four images of a quadruply lensed quasar lie on a rectangular hyperbola that passes through the unlensed quasar position and the center of the potential as well. Wynne and Schechter (2018) have shown that, for the singular isothermal elliptical potential (SIEP), the four images also lie on an `amplitude' ellipse centered on the quasar position with axes parallel to the hyperbola's asymptotes. Witt's hyperbola arises from equating the directions of both sides of the lens equation. The amplitude ellipse derives from equating the magnitudes. One can model any four points as an SIEP in three steps. 1. Find the rectangular hyperbola that passes through the points. 2. Find the aligned ellipse that also passes through them. 3. Find the hyperbola with asymptotes parallel to those of the first that passes through the center of the ellipse and the pair of images closest to each other. The second hyperbola and the ellipse give an SIEP that predicts the positions of the two remaining images where the curves intersect. Pinning the model to the closest pair guarantees a four image model. Such models permit rapid discrimination between gravitationally lensed quasars and random quartets of stars., Comment: Revised to address referee's suggestions. Published ApJ

We develop a robust method to model quadruply lensed quasars, relying heavily on the work of Witt (1996), who showed that for elliptical potentials, the four image positions, the source, and the lensing galaxy lie on a right hyperbola. For the singular isothermal elliptical potential, there exists a complementary ellipse centered on the source which also maps through the four images, with the same axis ratio as the potential but perpendicular to it. We first solve for Witt's hyperbola, reducing the allowable space of models to three dimensions. We then obtain the best fitting complementary ellipse. The simplest models of quadruple lenses require seven parameters to reproduce the observed image configurations, while the four positions give eight constraints. This leaves us one degree of freedom to use as a figure of merit. We applied our model to 29 known lenses, and include their figures of merit. We then modeled 100 random quartets. A selection criterion that sacrifices 20% of the known lenses can exclude 98% of the random quartets., Comment: Submitted to the MIT Undergraduate Research Journal. 8 pages

The primary goals of the STRong lensing Insights into the Dark Energy Survey (STRIDES) collaboration are to measure the dark energy equation of state parameter and the free streaming length of dark matter. To this aim, STRIDES is discovering strongly lensed quasars in the imaging data of the Dark Energy Survey and following them up to measure time delays, high resolution imaging, and spectroscopy sufficient to construct accurate lens models. In this paper, we first present forecasts for STRIDES. Then, we describe the STRIDES classification scheme, and give an overview of the Fall 2016 follow-up campaign. We continue by detailing the results of two selection methods, the Outlier Selection Technique and a morphological algorithm, and presenting lens models of a system, which could possibly be a lensed quasar in an unusual configuration. We conclude with the summary statistics of the Fall 2016 campaign. Including searches presented in companion papers (Anguita et al.; Ostrovski et al.), STRIDES followed up 117 targets identifying 7 new strongly lensed systems, and 7 nearly identical quasars (NIQs), which could be confirmed as lenses by the detection of the lens galaxy. 76 candidates were rejected and 27 remain otherwise inconclusive, for a success rate in the range 6-35\%. This rate is comparable to that of previous searches like SQLS even though the parent dataset of STRIDES is purely photometric and our selection of candidates cannot rely on spectroscopic information., Comment: (MNRAS in press; color scheme of Figures 1-4 improved with respect to v1)

Strong-gravitational lens systems with quadruply-imaged quasars (quads) are unique probes to address several fundamental problems in cosmology and astrophysics. Although they are intrinsically very rare, ongoing and planned wide-field deep-sky surveys are set to discover thousands of such systems in the next decade. It is thus paramount to devise a general framework to model strong-lens systems to cope with this large influx without being limited by expert investigator time. We propose such a general modelling framework (implemented with the publicly available software Lenstronomy) and apply it to uniformly model three-band Hubble Space Telescope Wide Field Camera 3 images of 13 quads. This is the largest uniformly modelled sample of quads to date and paves the way for a variety of studies. To illustrate the scientific content of the sample, we investigate the alignment between the mass and light distribution in the deflectors. The position angles of these distributions are well-aligned, except when there is strong external shear. However, we find no correlation between the ellipticity of the light and mass distributions. We also show that the observed flux-ratios between the images depart significantly from the predictions of simple smooth models. The departures are strongest in the bluest band, consistent with microlensing being the dominant cause in addition to millilensing. Future papers will exploit this rich dataset in combination with ground based spectroscopy and time delays to determine quantities such as the Hubble constant, the free streaming length of dark matter, and the normalization of the initial stellar mass function., Comment: 22 pages, 9 figures, 8 tables, Accepted to MNRAS. This version: updated Table 4 from the erratum

We report the serendipitous discovery of a quadruply-lensed source behind the z=0.095 edge-on disk galaxy 2MASXJ13170000-1405187, based on public imaging survey data from Pan-STARRS PS1 and the VISTA Hemisphere Survey. Follow-up imaging from Magellan/LDSS3 shows that the background source is spatially extended (i.e. not a QSO), and that two of the lensed images are observed through a prominent dust ring in the disk of the lens galaxy. We summarise results of preliminary modelling, which indicates an Einstein radius of 1.44 arcsec, and a K-band mass-to-light ratio of 0.5, relative to the solar value., Comment: Three pages, one figure; submitted to Research Notes of the AAS

We report upon the follow up of 34 candidate lensed quasars found in the Dark Energy Survey using NTT-EFOSC, Magellan-IMACS, KECK-ESI and SOAR-SAMI. These candidates were selected by a combination of double component fitting, morphological assessment and color analysis. Most systems followed up are indeed composed of at least one quasar image and 13 with two or more quasar images: two lenses, four projected binaries and seven Nearly Identical Quasar Pairs (NIQs). The two systems confirmed as genuine gravitationally lensed quasars are one quadruple at $z_s=1.713$ and one double at $z_s=1.515$. Lens modeling of these two systems reveals that both systems require very little contribution from the environment to reproduce the image configuration. Nevertheless, small flux anomalies can be observed in one of the images of the quad. Further observations of 9 inconclusive systems (including 7 NIQs) will allow to confirm (or not) their gravitational lens nature., Comment: 13 pages, 8 figures. MNRAS submitted (05/24). Approved by the DES Collaboration Wide Review

We report the quadruple nature of the source WISE 025942.9-163543 as observed in the VST-ATLAS survey. Spectra of the two brightest images show quasar emission lines at z=2.16. The system was discovered by splitting ATLAS "cutouts" of WISE sources with W1-W2 > 0.7, when possible, into three components. Followup Magellan images were used to obtain astrometry and g and i photometry, with i=18.78 and 19.73, respectively, for the brightest and faintest components. Absorption lines are observed at z=0.905 but there is little evidence for a lensing galaxy after PSF fitting and subtraction. Saha and Williams (2003) would classify ATLAS 0259-1635 as a short-axis quad. The larger and smaller diameters are 1.57 and 1.32 arcseconds, respectively. Modeling the lensing galaxy as a singular isothermal sphere with external shear, the largest and smallest predicted magnifications are 10.8 and 6.4 respectively., Comment: 3 pages, 1 figure

A substantial fraction the stellar mass attributed to galaxies is invisible: stars close to the hydrogen burning limit, brown dwarfs, white dwarfs, neutron stars and black holes. These constituents do, however, gravitationally micro-lens background quasars, thereby permitting measurement of the total stellar contribution to the mass surface density along the line of sight. We report the results of such a measurement using a sample of ten quadruply lensed quasars. We discuss the prospects for improving upon this measurement with a larger sample and describe efforts to find new quadruple lenses. If we invert our argument and take the stellar mass to be known, we derive a value for the fraction of the dark halo in MaCHOs (including 20 solar mass primordial black holes) of somthing less than 10%, confirming the widely ignored result of Mediavilla et al (2009)., Comment: Contribution to "Stellar Populations and the Distance Scale - A Conference in Honor of Jeremy Mould"; 7 pages

We investigate the flux ratio anomalies between macro-model predictions and the observed brightness of the supernova iPTF16geu, as published in a recent paper by More et al., 2017. This group suggested that these discrepancies are, qualitatively, likely due to microlensing. We analyze the plausibility of attributing this discrepancy to microlensing, and find that the discrepancy is too large to be due to microlensing alone. This is true whether one assumes knowledge of the luminosity of the supernova or allows the luminosity to be a free parameter. Varying the dark/stellar ratio likewise doesn't help. In addition, other macro-models with quadruplicity from external shear or ellipticity do not significantly improve to model. Finally, microlensing also makes it difficult to accurately determine the standard candle brightness of the supernova, as the likelihood plot for the intrinsic magnitude of the source (for a perfect macro-model) has a full width half maximum of 0.73 magnitudes. As such, the error for the standard candle brightness is quite large. This reduces the utility of the standard candle nature of type Ia supernovae., Comment: Submitted to MIT Journal of Undergraduate Research. 7 pages, 5 figures

We report on discovery results from a quasar lens search in the ATLAS public footprint, extending quasar lens searches to a regime without $u-$band or fiber-spectroscopic information, using a combination of data mining techniques on multi-band catalog magnitudes and image-cutout modelling. Spectroscopic follow-up campaigns, conducted at the 2.6m Nordic Optical Telescope (La Palma) and 3.6m New Technology Telescope (La Silla) in 2016, yielded seven pairs of quasars exhibiting the same lines at the same redshift and monotonic flux-ratios with wavelength (hereafter NIQs, Nearly Identical Quasar pairs). The quasar redshifts range between $\approx1.2$ and $\approx 2.7;$ contaminants are typically pairs of bright blue stars, quasar-star alignments along the line of sight, and narrow-line galaxies at $0.3

We report the discovery, spectroscopic confirmation and first lens models of the first two, strongly lensed quasars from a combined search in WISE and Gaia over the DES footprint. The four-image lensWGD2038-4008 (r.a.=20:38:02.65, dec.=-40:08:14.64) has source- and lens-redshifts $z_{s}=0.777 \pm 0.001$ and $z_l = 0.230 \pm 0.002$ respectively. Its deflector has effective radius $R_{\rm eff} \approx 3.4^{\prime\prime}$, stellar mass $\log(M_{\star}/M_{\odot}) = 11.64^{+0.20}_{-0.43}$, and shows extended isophotal shape variation. Simple lens models yield Einstein radii $R_{\rm E}=(1.30\pm0.04)^{\prime\prime},$ axis ratio $q=0.75\pm0.1$ (compatible with that of the starlight) and considerable shear-ellipticity degeneracies. The two-image lensWGD2021-4115 (r.a.=20:21:39.45, dec.=--41:15:57.11) has $z_{s}=1.390\pm0.001$ and $z_l = 0.335 \pm 0.002$, and Einstein radius $R_{\rm E} = (1.1\pm0.1)^{\prime\prime},$ but higher-resolution imaging is needed to accurately separate the deflector and faint quasar image. We also show high-rank candidate doubles selected this way, some of which have been independently identified with different techniques, and discuss a DES+WISE quasar multiplet selection., Comment: MNRAS subm. 21/10/2017, awaiting reviewer selection. This paper has been approved by DES Collaboration-Wide Review

Gravitationally lensed quasars are powerful and versatile astrophysical tools, but they are challengingly rare. In particular, only ~25 well-characterized quadruple systems are known to date. To refine the target catalogue for the forthcoming Taipan Galaxy Survey, the images of a large number of sources are being visually inspected in order to identify objects that are confused by a foreground star or galaxies that have a distinct multi-component structure. An unexpected by-product of this work has been the serendipitous discovery of about a dozen galaxies that appear to be lensing quasars, i.e. pairs or quartets of foreground stellar objects in close proximity to the target source. Here we report two diamond-shaped systems. Follow-up spectroscopy with the IMACS instrument on the 6.5m Magellan Baade telescope confirms one of these as a z = 1.975 quasar quadruply lensed by a double galaxy at z = 0.293. Photometry from publicly available survey images supports the conclusion that the other system is a highly sheared quadruply-imaged quasar. In starting with objects thought to be galaxies, our lens finding technique complements the conventional approach of first identifying sources with quasar-like colours and subsequently finding evidence of lensing., Comment: Accepted to MNRAS

We have analyzed images from the VST ATLAS survey to identify candidate gravitationally lensed quasar systems in a sample of WISE sources with W1 - W2 > 0.7. Results from followup spectroscopy with the Baade 6.5 m telescope are presented for eight systems. One of these is a quadruply lensed quasar and two are doubly lensed systems. Two are projected superpositions of two quasars at different redshifts. In one system two quasars, though at the same redshift, have very different emission line profiles, and constitute a physical binary. In two systems the component spectra are consistent with the lensing hypothesis, after allowing for micro-lensing. But as no lensing galaxy is detected in these two, we classify them as lensless twins. More extensive observations are needed to establish whether they are in fact lensed quasars or physical binaries., Comment: Accepted for publication in the Astronomical Journal. Title changed to reflect the confirmation of one lensless twin as a lensed double and the inclusion a second lensed double. 27 pages, 8 figures

We argue that the stellar velocity dispersion observed in an elliptical galaxy is a good proxy for the halo velocity dispersion. As dark matter halos are almost completely characterized by a single scale parameter, the stellar velocity dispersion tells us the virial radius of the halo and the mass contained within. This permits non-dimensionalizing of the stellar mass and effective radius axes of the stellar mass fundamental plane by the virial radius and halo mass, respectively., Comment: 4 pages. Contribution to IAU Symposium 317 "The General Assembly of Halos" edited by A. Bragaglia, M. Arnaboldi, M. Rejkuba & D. Romano. Four typos corrected

We present spectroscopic confirmation of two new lensed quasars via data obtained at the 6.5m Magellan/Baade Telescope. The lens candidates have been selected from the Dark Energy Survey (DES) and WISE based on their multi-band photometry and extended morphology in DES images. Images of DES J0115-5244 show two blue point sources at either side of a red galaxy. Our long-slit data confirm that both point sources are images of the same quasar at $z_{s}=1.64.$ The Einstein Radius estimated from the DES images is $0.51$". DES J2200+0110 is in the area of overlap between DES and the Sloan Digital Sky Survey (SDSS). Two blue components are visible in the DES and SDSS images. The SDSS fiber spectrum shows a quasar component at $z_{s}=2.38$ and absorption compatible with Mg II and Fe II at $z_{l}=0.799$, which we tentatively associate with the foreground lens galaxy. The long-slit Magellan spectra show that the blue components are resolved images of the same quasar. The Einstein Radius is $0.68$" corresponding to an enclosed mass of $1.6\times10^{11}\,M_{\odot}.$ Three other candidates were observed and rejected, two being low-redshift pairs of starburst galaxies, and one being a quasar behind a blue star. These first confirmation results provide an important empirical validation of the data-mining and model-based selection that is being applied to the entire DES dataset., Comment: 7 pages, 1 figure, 2 tables, MNRAS subm. This paper includes data gathered with the 6.5m Baade Telescopes located at Las Campanas Observatory, Chile. This paper has gone through internal review by the DES collaboration, FERMILAB-PUB-15-341-AE

We measure the stellar mass surface densities of early type galaxies by observing the micro-lensing of macro-lensed quasars caused by individual stars, including stellar remnants, brown dwarfs and red dwarfs too faint to produce photometric or spectroscopic signatures. Our method measures the graininess of the gravitational potential, in contrast to methods that decompose a smooth total gravitational potential into two smooth components, one stellar and one dark. We find the median likelihood value for the calibration factor F by which Salpeter stellar masses (with a low mass cutoff of 0.1 solar masses) must be multiplied is 1.23, with a one sigma confidence range of 0.77 < F < 2.10., Comment: To be published in IAU Symposium 311, Galaxy Masses as Constraints of Formation Models, ed. M. Cappellari & S. Courteau, Cambridge Univ. Press, in press (2014). This article draws heavily upon the very much longer arXiv:1405.0038

We measure the stellar mass surface densities of early type galaxies by observing the micro-lensing of macro-lensed quasars caused by individual stars, including stellar remnants, brown dwarfs and red dwarfs too faint to produce photometric or spectroscopic signatures. Instead of observing multiple micro-lensing events in a single system, we combine single epoch X-ray snapshots of ten quadruple systems, and compare the measured relative magnifications for the images with those computed from macro-models. We use these to normalize a stellar mass fundamental plane constructed using a Salpeter IMF with a low mass cutoff of 0.1 solar mass and treat the zeropoint of the surface mass density as a free parameter. Our method measures the graininess of the gravitational potential produced by individual stars, in contrast to methods that decompose a smooth total gravitational potential into two smooth components, one stellar and one dark. We find the median likelihood value for the normalization factor F by which the Salpeter stellar masses must be multiplied is 1.23, with a one sigma confidence range, dominated by small number statistics, of 0.77 < F < 2.10, Comment: Revised in response to referee's suggestions and re-submitted to ApJ; changes to the adopted effective radii propagate to a new value of the factor F (by which Salpeter stellar masses must be multiplied) of 1.23

The CXOCY J220132.8-320144 system consists of an edge-on spiral galaxy lensing a background quasar into two bright images. Previous efforts to constrain the mass distribution in the galaxy have suggested that at least one additional image must be present (Castander et al. 2006). These extra images may be hidden behind the disk which features a prominent dust lane. We present and analyze Hubble Space Telescope (HST) observations of the system. We do not detect any extra images, but the observations further narrow the observable parameters of the lens system. We explore a range of models to describe the mass distribution in the system and find that a variety of acceptable model fits exist. All plausible models require 2 magnitudes of dust extinction in order to obscure extra images from detection, and some models may require an offset between the center of the galaxy and the center of the dark matter halo of 1 kiloparsec. Currently unobserved images will be detectable by future James Webb Space Telescope (JWST) observations and will provide strict constraints on the fraction of mass in the disk., Comment: 10 pages, 8 figures, 6 tables. Minor changes, version accepted for publication in ApJ

Q1: Why deploy N wavefront sensors on a three mirror anastigmat (TMA) and not N + 1? Q2: Why measure M Zernike coefficients and not M + 1? Q3: Why control L rigid body degrees of freedom (total) on the secondary and tertiary and not L + 1? The usual answer: "We did a lot of ray tracing and N,M, and L seemed OK." We show how straightforward results from aberration theory may be used to address these questions. We consider, in particular, the case of a three mirror anastigmat., Comment: 6 pages, 5 figures. SPIE Astronomical Telescopes + Instrumentation

We present a microlensing analysis of 61 Chandra observations of 14 quadruply lensed quasars. X-ray flux measurements of the individual quasar images give a clean determination of the microlensing effects in the lensing galaxy and thus offer a direct assessment of the local fraction of stellar matter making up the total integrated mass along the lines of sight through the lensing galaxy. A Bayesian analysis of the ensemble of lensing galaxies gives a most likely local stellar fraction of 7%, with the other 93% in a smooth, dark matter component, at an average impact parameter R_c of 6.6 kpc from the center of the lensing galaxy. We divide the systems into smaller ensembles based on R_c and find that the most likely local stellar fraction varies qualitatively and quantitatively as expected, decreasing as a function of R_c., Comment: 13 pages, published in ApJ, 744:111, 2012 January 10