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Sample records for strong lensing tests

  1. Cosmological test using strong gravitational lensing systems

    NASA Astrophysics Data System (ADS)

    Yuan, C. C.; Wang, F. Y.

    2015-09-01

    As one of the probes of universe, strong gravitational lensing systems allow us to compare different cosmological models and constrain vital cosmological parameters. This purpose can be reached from the dynamic and geometry properties of strong gravitational lensing systems, for instance, time-delay Δτ of images, the velocity dispersion σ of the lensing galaxies and the combination of these two effects, Δτ/σ2. In this paper, in order to carry out one-on-one comparisons between ΛCDM universe and Rh = ct universe, we use a sample containing 36 strong lensing systems with the measurement of velocity dispersion from the Sloan Lens Advanced Camera for Surveys (SLACS) and Lens Structure and Dynamic survey (LSD) survey. Concerning the time-delay effect, 12 two-image lensing systems with Δτ are also used. In addition, Monte Carlo simulations are used to compare the efficiency of the three methods as mentioned above. From simulations, we estimate the number of lenses required to rule out one model at the 99.7 per cent confidence level. Comparing with constraints from Δτ and the velocity dispersion σ, we find that using Δτ/σ2 can improve the discrimination between cosmological models. Despite the independence tests of these methods reveal a correlation between Δτ/σ2 and σ, Δτ/σ2 could be considered as an improved method of σ if more data samples are available.

  2. GALAXY-SCALE STRONG-LENSING TESTS OF GRAVITY AND GEOMETRIC COSMOLOGY: CONSTRAINTS AND SYSTEMATIC LIMITATIONS

    SciTech Connect

    Schwab, Josiah; Bolton, Adam S.; Rappaport, Saul A. E-mail: bolton@ifa.hawaii.ed E-mail: bolton@physics.utah.ed

    2010-01-01

    Galaxy-scale strong gravitational lenses with measured stellar velocity dispersions allow a test of the weak-field metric on kiloparsec scales and a geometric measurement of the cosmological distance-redshift relation, provided that the mass-dynamical structure of the lensing galaxies can be independently constrained to a sufficient degree. We combine data on 53 galaxy-scale strong lenses from the Sloan Lens ACS Survey with a well-motivated fiducial set of lens-galaxy parameters to find (1) a constraint on the post-Newtonian parameter gamma = 1.01 +- 0.05, and (2) a determination of OMEGA{sub L}AMBDA = 0.75 +- 0.17 under the assumption of a flat universe. These constraints assume that the underlying observations and priors are free of systematic error. We evaluate the sensitivity of these results to systematic uncertainties in (1) total mass-profile shape, (2) velocity anisotropy, (3) light-profile shape, and (4) stellar velocity dispersion. Based on these sensitivities, we conclude that while such strong-lens samples can, in principle, provide an important tool for testing general relativity and cosmology, they are unlikely to yield precision measurements of gamma and OMEGA{sub L}AMBDA unless the properties of the lensing galaxies are independently constrained with substantially greater accuracy than at present.

  3. LENSED: a code for the forward reconstruction of lenses and sources from strong lensing observations

    NASA Astrophysics Data System (ADS)

    Tessore, Nicolas; Bellagamba, Fabio; Metcalf, R. Benton

    2016-09-01

    Robust modelling of strong lensing systems is fundamental to exploit the information they contain about the distribution of matter in galaxies and clusters. In this work, we present LENSED, a new code which performs forward parametric modelling of strong lenses. LENSED takes advantage of a massively parallel ray-tracing kernel to perform the necessary calculations on a modern graphics processing unit (GPU). This makes the precise rendering of the background lensed sources much faster, and allows the simultaneous optimisation of tens of parameters for the selected model. With a single run, the code is able to obtain the full posterior probability distribution for the lens light, the mass distribution and the background source at the same time. LENSED is first tested on mock images which reproduce realistic space-based observations of lensing systems. In this way, we show that it is able to recover unbiased estimates of the lens parameters, even when the sources do not follow exactly the assumed model. Then, we apply it to a subsample of the SLACS lenses, in order to demonstrate its use on real data. The results generally agree with the literature, and highlight the flexibility and robustness of the algorithm.

  4. Roulettes: a weak lensing formalism for strong lensing: I. Overview

    NASA Astrophysics Data System (ADS)

    Clarkson, Chris

    2016-08-01

    We present a new perspective on gravitational lensing. We describe a new extension of the weak lensing formalism capable of describing strongly lensed images. By integrating the nonlinear geodesic deviation equation, the amplification matrix of weak lensing is generalised to a sum over independent amplification tensors of increasing rank. We show how an image distorted by a generic lens may be constructed as a sum over ‘roulettes’, which are the natural curves associated with the independent spin modes of the amplification tensors. Highly distorted images can be constructed even for large sources observed near or within the Einstein radius of a lens where the shear and convergence are large. The amplitude of each roulette is formed from a sum over appropriate derivatives of the lensing potential. Consequently, measuring these individual roulettes for images around a lens gives a new way to reconstruct a strong lens mass distribution without requiring a lens model. This formalism generalises the convergence, shear and flexion of weak lensing to arbitrary order, and provides a unified bridge between the strong and weak lensing regimes. This overview paper is accompanied by a much more detailed paper II, arXiv:1603.04652.

  5. Cooking with Strong Lenses and Other Ingredients

    NASA Astrophysics Data System (ADS)

    Bolton, Adam; SLACS; BELLS; SDSS-III

    2013-07-01

    Strong lensing offers the most direct method for constraining the distribution of mass in galaxies at cosmological distances. The combination of strong lensing with other observables increases its power, but often in ways that are model-dependent and resistant to intuition. In this talk, I will unpack the information content of spectroscopic, photometric, kinematic, and strong-lensing observables as they translate into constraints on the macroscopic distribution of luminous and dark matter in massive elliptical galaxies. I will also highlight how the choice of priors and analysis methods affects the conclusions drawn from a given set of observations. Finally, in this context I will present the latest results from observational efforts to extend strong-lensing analyses to lower mass galaxies in the Sloan Lens ACS Survey (SLACS) and to earlier cosmic times in the BOSS Emission-Line Lens Survey (BELLS).

  6. Cosmological Applications of Strong Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Paraficz, Danuta

    2009-11-01

    One of the most intriguing recent results in physics is the growing evidence that an unknown energy field and an unknown kind of matter are the major components of the Universe (70% and 30%, respectively; see e.g. Riess et al. 1998, Spergel et al. 2007). Understanding and estimating the precise value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown by Refsdal (1964), H0, !m and !! can be measured based on the time delay ("t) between multiply lensed images of QSOs, because "t depends on H0 and on the distances to lens and source, hence!m and !!. Determination of cosmological parameters using gravitational lensing suffers from some degeneracies, but it is based on well understood physics and unlike distance ladder methods there are no calibration issues. Moreover, it has an advantage over some of the leading methods (such as Type Ia SNe) in that it is a purely cosmological approach. In this thesis, the property of strong gravitational lensing - time delay - is extensively explored. Strong gravitational lensing, and in particular time delays, are investigated here both theoretically and observationally. The focus is on the time delay as a cosmological and astrophysical tool to constrain H0, !m, !!, and to measure the masses of lensing galaxies. The first Chapter presents a historical background of gravitational lensing. It explains the process involved in creating the theory of gravitational lenses. It shows how Newton and then Einstein developed the concept and how Refsdal and others made it a cosmological tool. We present in more detail how gravitational lensing influenced the history of physics by being the first proof of Einstein's theory of gravity. The Chapter ends by discussing the first observational discovery of a strong

  7. The Strong Lensing Time Delay Challenge (2014)

    NASA Astrophysics Data System (ADS)

    Liao, Kai; Dobler, G.; Fassnacht, C. D.; Treu, T.; Marshall, P. J.; Rumbaugh, N.; Linder, E.; Hojjati, A.

    2014-01-01

    Time delays between multiple images in strong lensing systems are a powerful probe of cosmology. At the moment the application of this technique is limited by the number of lensed quasars with measured time delays. However, the number of such systems is expected to increase dramatically in the next few years. Hundred such systems are expected within this decade, while the Large Synoptic Survey Telescope (LSST) is expected to deliver of order 1000 time delays in the 2020 decade. In order to exploit this bounty of lenses we needed to make sure the time delay determination algorithms have sufficiently high precision and accuracy. As a first step to test current algorithms and identify potential areas for improvement we have started a "Time Delay Challenge" (TDC). An "evil" team has created realistic simulated light curves, to be analyzed blindly by "good" teams. The challenge is open to all interested parties. The initial challenge consists of two steps (TDC0 and TDC1). TDC0 consists of a small number of datasets to be used as a training template. The non-mandatory deadline is December 1 2013. The "good" teams that complete TDC0 will be given access to TDC1. TDC1 consists of thousands of lightcurves, a number sufficient to test precision and accuracy at the subpercent level, necessary for time-delay cosmography. The deadline for responding to TDC1 is July 1 2014. Submissions will be analyzed and compared in terms of predefined metrics to establish the goodness-of-fit, efficiency, precision and accuracy of current algorithms. This poster describes the challenge in detail and gives instructions for participation.

  8. Subaru Weak Lensing Measurements of Four Strong Lensing Clusters: Are Lensing Clusters Over-Concentrated?

    SciTech Connect

    Oguri, Masamune; Hennawi, Joseph F.; Gladders, Michael D.; Dahle, Haakon; Natarajan, Priyamvada; Dalal, Neal; Koester, Benjamin P.; Sharon, Keren; Bayliss, Matthew

    2009-01-29

    We derive radial mass profiles of four strong lensing selected clusters which show prominent giant arcs (Abell 1703, SDSS J1446+3032, SDSS J1531+3414, and SDSS J2111-0115), by combining detailed strong lens modeling with weak lensing shear measured from deep Subaru Suprime-cam images. Weak lensing signals are detected at high significance for all four clusters, whose redshifts range from z = 0.28 to 0.64. We demonstrate that adding strong lensing information with known arc redshifts significantly improves constraints on the mass density profile, compared to those obtained from weak lensing alone. While the mass profiles are well fitted by the universal form predicted in N-body simulations of the {Lambda}-dominated cold dark matter model, all four clusters appear to be slightly more centrally concentrated (the concentration parameters c{sub vir} {approx} 8) than theoretical predictions, even after accounting for the bias toward higher concentrations inherent in lensing selected samples. Our results are consistent with previous studies which similarly detected a concentration excess, and increases the total number of clusters studied with the combined strong and weak lensing technique to ten. Combining our sample with previous work, we find that clusters with larger Einstein radii are more anomalously concentrated. We also present a detailed model of the lensing cluster Abell 1703 with constraints from multiple image families, and find the dark matter inner density profile to be cuspy with the slope consistent with -1, in agreement with expectations.

  9. SARCS strong-lensing galaxy groups. II. Mass-concentration relation and strong-lensing bias

    NASA Astrophysics Data System (ADS)

    Foëx, G.; Motta, V.; Jullo, E.; Limousin, M.; Verdugo, T.

    2014-12-01

    Aims: Various studies have shown a lensing bias in the mass-concentration relation of cluster-scale structures that is the result of an alignment of the major axis and the line of sight. In this paper, we aim to study this lensing bias through the mass-concentration relation of galaxy groups, thus extending observational constraints to dark matter haloes of mass ~1013-1014 M⊙. Methods: Our work is based on the stacked weak-lensing analysis of a sample of 80 strong-lensing galaxy groups. By combining several lenses, we significantly increase the signal-to-noise ratio of the lensing signal, thus providing constraints on the mass profile that cannot be obtained for individual objects. The resulting shear profiles were fitted with various mass models, among them the Navarro-Frank-White (NFW) profile, which provides an estimate of the total mass and of the concentration of the composite galaxy groups. Results: The main results of our analysis are the following: (i) the lensing signal does not allow us to firmly distinguish between a simple singular isothermal sphere mass distribution and the expected NFW mass profile; (ii) we obtain an average concentration c200 = 8.6-1.3+2.1 that is much higher than the value expected from numerical simulations for the corresponding average mass M200 = 0.73-0.10+0.11 × 1014 M⊙; (iii) the combination of our results with those at larger mass scales gives a mass-concentration relation c(M) of more than two decades in mass, whose slope disagrees with predictions from numerical simulations using unbiased populations of dark matter haloes; (iv) our combined c(M) relation matches results from simulations that only used haloes with a large strong-lensing cross-section, that is, elongated with a major axis close to the line of sight; (v) for the simplest case of prolate haloes, we estimate a lower limit on the minor-to-major axis ratio a/c = 0.5 for the average SARCS galaxy group with a toy model. Conclusions: Our analysis based on galaxy

  10. Constraints on holographic cosmologies from strong lensing systems

    SciTech Connect

    Cárdenas, Víctor H.; Bonilla, Alexander; Motta, Verónica; Campo, Sergio del E-mail: alex.bonilla@uv.cl E-mail: sdelcamp@ucv.cl

    2013-11-01

    We use strongly gravitationally lensed (SGL) systems to put additional constraints on a set of holographic dark energy models. Data available in the literature (redshift and velocity dispersion) is used to obtain the Einstein radius and compare it with model predictions. We found that the ΛCDM is the best fit to the data. Although a preliminary statistical analysis seems to indicate that two of the holographic models studied show interesting agreement with observations, a stringent test lead us to the result that neither of the holographic models are competitive with the ΛCDM. These results highlight the importance of Strong Lensing measurements to provide additional observational constraints to alternative cosmological models, which are necessary to shed some light into the dark universe.

  11. PICS: Simulations of Strong Gravitational Lensing in Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Li, Nan; Gladders, Michael D.; Rangel, Esteban M.; Florian, Michael K.; Bleem, Lindsey E.; Heitmann, Katrin; Habib, Salman; Fasel, Patricia

    2016-09-01

    Gravitational lensing has become one of the most powerful tools available for investigating the “dark side” of the universe. Cosmological strong gravitational lensing, in particular, probes the properties of the dense cores of dark matter halos over decades in mass and offers the opportunity to study the distant universe at flux levels and spatial resolutions otherwise unavailable. Studies of strongly lensed variable sources offer even further scientific opportunities. One of the challenges in realizing the potential of strong lensing is to understand the statistical context of both the individual systems that receive extensive follow-up study, as well as that of the larger samples of strong lenses that are now emerging from survey efforts. Motivated by these challenges, we have developed an image simulation pipeline, Pipeline for Images of Cosmological Strong lensing (PICS), to generate realistic strong gravitational lensing signals from group- and cluster-scale lenses. PICS uses a low-noise and unbiased density estimator based on (resampled) Delaunay Tessellations to calculate the density field; lensed images are produced by ray-tracing images of actual galaxies from deep Hubble Space Telescope observations. Other galaxies, similarly sampled, are added to fill in the light cone. The pipeline further adds cluster member galaxies and foreground stars into the lensed images. The entire image ensemble is then observed using a realistic point-spread function that includes appropriate detector artifacts for bright stars. Noise is further added, including such non-Gaussian elements as noise window-paning from mosaiced observations, residual bad pixels, and cosmic rays. The aim is to produce simulated images that appear identical—to the eye (expert or otherwise)—to real observations in various imaging surveys.

  12. Line-of-sight structure toward strong lensing galaxy clusters

    SciTech Connect

    Bayliss, Matthew B.; Johnson, Traci; Sharon, Keren; Gladders, Michael D.; Oguri, Masamune

    2014-03-01

    We present an analysis of the line-of-sight structure toward a sample of 10 strong lensing cluster cores. Structure is traced by groups that are identified spectroscopically in the redshift range, 0.1 ≤ z ≤ 0.9, and we measure the projected angular and comoving separations between each group and the primary strong lensing clusters in each corresponding line of sight. From these data we measure the distribution of projected angular separations between the primary strong lensing clusters and uncorrelated large-scale structure as traced by groups. We then compare the observed distribution of angular separations for our strong lensing selected lines of sight against the distribution of groups that is predicted for clusters lying along random lines of sight. There is clear evidence for an excess of structure along the line of sight at small angular separations (θ ≤ 6') along the strong lensing selected lines of sight, indicating that uncorrelated structure is a significant systematic that contributes to producing galaxy clusters with large cross sections for strong lensing. The prevalence of line-of-sight structure is one of several biases in strong lensing clusters that can potentially be folded into cosmological measurements using galaxy cluster samples. These results also have implications for current and future studies—such as the Hubble Space Telescope Frontier Fields—that make use of massive galaxy cluster lenses as precision cosmological telescopes; it is essential that the contribution of line-of-sight structure be carefully accounted for in the strong lens modeling of the cluster lenses.

  13. A comparison of cosmological models using strong gravitational lensing galaxies

    SciTech Connect

    Melia, Fulvio; Wei, Jun-Jie; Wu, Xue-Feng E-mail: jjwei@pmo.ac.cn E-mail: fmelia@email.arizona.edu E-mail: xfwu@pmo.ac.cn

    2015-01-01

    Strongly gravitationally lensed quasar-galaxy systems allow us to compare competing cosmologies as long as one can be reasonably sure of the mass distribution within the intervening lens. In this paper, we assemble a catalog of 69 such systems from the Sloan Lens ACS and Lens Structure and Dynamics surveys suitable for this analysis, and carry out a one-on-one comparison between the standard model, ΛCDM, and the R{sub h}=ct universe, which has thus far been favored by the application of model selection tools to other kinds of data. We find that both models account for the lens observations quite well, though the precision of these measurements does not appear to be good enough to favor one model over the other. Part of the reason is the so-called bulge-halo conspiracy that, on average, results in a baryonic velocity dispersion within a fraction of the optical effective radius virtually identical to that expected for the whole luminous-dark matter distribution modeled as a singular isothermal ellipsoid, though with some scatter among individual sources. Future work can greatly improve the precision of these measurements by focusing on lensing systems with galaxies as close as possible to the background sources. Given the limitations of doing precision cosmological testing using the current sample, we also carry out Monte Carlo simulations based on the current lens measurements to estimate how large the source catalog would have to be in order to rule out either model at a ∼99.7% confidence level. We find that if the real cosmology is ΛCDM, a sample of ∼200 strong gravitational lenses would be sufficient to rule out R{sub h}=ct at this level of accuracy, while ∼300 strong gravitational lenses would be required to rule out ΛCDM if the real universe were instead R{sub h}=ct. The difference in required sample size reflects the greater number of free parameters available to fit the data with ΛCDM. We point out that, should the R{sub h}=ct universe eventually

  14. A Comparison of Cosmological Models Using Strong Gravitational Lensing Galaxies

    NASA Astrophysics Data System (ADS)

    Melia, Fulvio; Wei, Jun-Jie; Wu, Xue-Feng

    2015-01-01

    Strongly gravitationally lensed quasar-galaxy systems allow us to compare competing cosmologies as long as one can be reasonably sure of the mass distribution within the intervening lens. In this paper, we assemble a catalog of 69 such systems from the Sloan Lens ACS and Lens Structure and Dynamics surveys suitable for this analysis, and carry out a one-on-one comparison between the standard model, ΛCDM, and the {{R}h}=ct universe, which has thus far been favored by the application of model selection tools to other kinds of data. We find that both models account for the lens observations quite well, though the precision of these measurements does not appear to be good enough to favor one model over the other. Part of the reason is the so-called bulge-halo conspiracy that, on average, results in a baryonic velocity dispersion within a fraction of the optical effective radius virtually identical to that expected for the whole luminous-dark matter distribution modeled as a singular isothermal ellipsoid, though with some scatter among individual sources. Future work can greatly improve the precision of these measurements by focusing on lensing systems with galaxies as close as possible to the background sources. Given the limitations of doing precision cosmological testing using the current sample, we also carry out Monte Carlo simulations based on the current lens measurements to estimate how large the source catalog would have to be in order to rule out either model at a ˜ 99.7% confidence level. We find that if the real cosmology is ΛCDM, a sample of ˜ 200 strong gravitational lenses would be sufficient to rule out {{R}h}=ct at this level of accuracy, while ˜ 300 strong gravitational lenses would be required to rule out ΛCDM if the real universe were instead {{R}h}=ct. The difference in required sample size reflects the greater number of free parameters available to fit the data with ΛCDM. We point out that, should the {{R}h}=ct universe eventually emerge as

  15. The Distance Duality Relation from Strong Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Liao, Kai; Li, Zhengxiang; Cao, Shuo; Biesiada, Marek; Zheng, Xiaogang; Zhu, Zong-Hong

    2016-05-01

    Under very general assumptions of the metric theory of spacetime, photons traveling along null geodesics and photon number conservation, two observable concepts of cosmic distance, i.e., the angular diameter and the luminosity distances are related to each other by the so-called distance duality relation (DDR) {D}L={D}A{(1+z)}2. Observational validation of this relation is quite important because any evidence of its violation could be a signal of new physics. In this paper we introduce a new method to test the DDR based on strong gravitational lensing systems and type Ia supernovae (SNe Ia) under a flat universe. The method itself is worth attention because unlike previously proposed techniques, it does not depend on all other prior assumptions concerning the details of cosmological model. We tested it using a new compilation of strong lensing (SL) systems and JLA compilation of SNe Ia and found no evidence of DDR violation. For completeness, we also combined it with previous cluster data and showed its power on constraining the DDR. It could become a promising new probe in the future in light of forthcoming massive SL surveys and because of expected advances in galaxy cluster modeling.

  16. Constraints on cosmological models from strong gravitational lensing systems

    SciTech Connect

    Cao, Shuo; Pan, Yu; Zhu, Zong-Hong; Biesiada, Marek; Godlowski, Wlodzimierz E-mail: panyu@cqupt.edu.cn E-mail: godlowski@uni.opole.pl

    2012-03-01

    Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structure, formation, and evolution). Using the gravitational lensing theory and cluster mass distribution model, we try to collect a relatively complete observational data concerning the Hubble constant independent ratio between two angular diameter distances D{sub ds}/D{sub s} from various large systematic gravitational lens surveys and lensing by galaxy clusters combined with X-ray observations, and check the possibility to use it in the future as complementary to other cosmological probes. On one hand, strongly gravitationally lensed quasar-galaxy systems create such a new opportunity by combining stellar kinematics (central velocity dispersion measurements) with lensing geometry (Einstein radius determination from position of images). We apply such a method to a combined gravitational lens data set including 70 data points from Sloan Lens ACS (SLACS) and Lens Structure and Dynamics survey (LSD). On the other hand, a new sample of 10 lensing galaxy clusters with redshifts ranging from 0.1 to 0.6 carefully selected from strong gravitational lensing systems with both X-ray satellite observations and optical giant luminous arcs, is also used to constrain three dark energy models (ΛCDM, constant w and CPL) under a flat universe assumption. For the full sample (n = 80) and the restricted sample (n = 46) including 36 two-image lenses and 10 strong lensing arcs, we obtain relatively good fitting values of basic cosmological parameters, which generally agree with the results already known in the literature. This results encourages further development of this method and its use on larger samples obtained in the future.

  17. Radio monitoring campaigns of six strongly lensed quasars

    NASA Astrophysics Data System (ADS)

    Rumbaugh, N.; Fassnacht, C. D.; McKean, J. P.; Koopmans, L. V. E.; Auger, M. W.; Suyu, S. H.

    2015-06-01

    We observed six strongly lensed, radio-loud quasars (MG 0414+0534, CLASS B0712+472, JVAS B1030+074, CLASS B1127+385, CLASS B1152+199, and JVAS B1938+666) in order to identify systems suitable for measuring cosmological parameters using time delays between their multiple images. These systems are in standard two- and four-image configurations, with B1938 having a faint secondary pair of images. Two separate monitoring campaigns were carried out using the Very Large Array (VLA) and upgraded VLA. Light curves were extracted for each individual lensed image and analysed for signs of intrinsic variability. While it was not possible to measure time delays from these data, χ2-based and structure function tests found evidence for variability in a majority of the light curves. B0712 and B1030 had particularly strong variations, exhibiting linear flux trends. These results suggest that most of these systems should be targeted with follow-up monitoring campaigns, especially B0712 and B1030. We estimate that we can measure time delays for these systems with precisions of 0.5-3.5 d using two more seasons of monitoring.

  18. Strong Lensing Mass Reconstruction: from Frontier Fields to the Typical Lensing Clusters of Future Surveys

    NASA Astrophysics Data System (ADS)

    Sharon, Keren

    2015-08-01

    Driven by the unprecedented wealth of high quality data that is accumulating for the Frontier Fields, they are becoming some of the best-studied strong lensing clusters to date, and probably the next few years. As will be discussed intensively in this focus meeting, the FF prove transformative for many fields: from studies of the high redshift Universe, to the assembly and structure of the clusters themselves. The FF data and the extensive collaborative effort around this program will also allow us to examine and improve upon current lens modeling techniques. Strong lensing is a powerful tool for mass reconstruction of the cores of galaxy clusters of all scales, providing an estimate of the total (dark and seen) projected mass density distribution out to ~0.5 Mpc. Though SL mass may be biased by contribution from structures along the line of sight, its strength is that it is relatively insensitive to assumptions on cluster baryon astrophysics and dynamical state. Like the Frontier Fields clusters, the most "famous" strong lensing clusters are at the high mass end; they lens dozens of background sources into multiple images, providing ample lensing constraints. In this talk, I will focus on how we can leverage what we learn from modeling the FF clusters in strong lensing studies of the hundreds of clusters that will be discovered in upcoming surveys. In typical clusters, unlike the Frontier Fields, the Bullet Cluster and A1689, we observe only one to a handful of background sources, and have limited lensing constraints. I will describe the limitations that such a configuration imposes on strong lens modeling, highlight measurements that are robust to the richness of lensing evidence, and address the sources of uncertainty and what sort of information can help reduce those uncertainties. This category of lensing clusters is most relevant to the wide cluster surveys of the future.

  19. The STRong-lensing Insights into Dark Energy Survey (STRIDES)

    NASA Astrophysics Data System (ADS)

    Treu, Tommaso; Agnello, Adriano; Strides Team

    2015-01-01

    Recent work has demonstrated that strongly lensed quasars can be used to measure cosmological parameters with high accuracy and precision. The constraints obtained from time delays are comparable in precision to those obtained by baryonic acoustic oscillation experiments and provide a powerful complement to other probes of dark energy like the cosmic microwave background (Suyu et al. 2014). At the moment, a main limitation of this technique is that lensed quasars are rare in the sky and not enough suitable lenses are known. To overcome this challenge we have formed a DES broad external collaboration (STRIDES), aimed at discovering and following-up 100 previously unknown gravitationally lensed quasars. I will present novel search algorithms based on data mining techniques as well as the first results from the search.

  20. Cosmological constraints from strong gravitational lensing in clusters of galaxies.

    PubMed

    Jullo, Eric; Natarajan, Priyamvada; Kneib, Jean-Paul; D'Aloisio, Anson; Limousin, Marceau; Richard, Johan; Schimd, Carlo

    2010-08-20

    Current efforts in observational cosmology are focused on characterizing the mass-energy content of the universe. We present results from a geometric test based on strong lensing in galaxy clusters. Based on Hubble Space Telescope images and extensive ground-based spectroscopic follow-up of the massive galaxy cluster Abell 1689, we used a parametric model to simultaneously constrain the cluster mass distribution and dark energy equation of state. Combining our cosmological constraints with those from x-ray clusters and the Wilkinson Microwave Anisotropy Probe 5-year data gives Omega(m) = 0.25 +/- 0.05 and w(x) = -0.97 +/- 0.07, which are consistent with results from other methods. Inclusion of our method with all other available techniques brings down the current 2sigma contours on the dark energy equation-of-state parameter w(x) by approximately 30%. PMID:20724628

  1. Strong lensing in the Einstein-Straus solution

    NASA Astrophysics Data System (ADS)

    Schücker, Thomas

    2009-07-01

    We analyse strong lensing in the Einstein-Straus solution with positive cosmological constant. Our result confirms Rindler and Ishak's finding that a positive cosmological constant decreases the bending of light by an isolated spherical mass. In agreement with an analysis by Ishak et al., this decrease is found to be attenuated by a homogeneous mass distribution added around the spherical mass and by a recession of the observer. For concreteness we compare the theory to the light deflection of the lensed quasar SDSS J1004+4112.

  2. Strong gravitational lensing in a noncommutative black-hole spacetime

    NASA Astrophysics Data System (ADS)

    Ding, Chikun; Kang, Shuai; Chen, Chang-Yong; Chen, Songbai; Jing, Jiliang

    2011-04-01

    Noncommutative geometry may be a starting point to a quantum gravity. We study the influence of the spacetime noncommutative parameter on the strong field gravitational lensing in the noncommutative Schwarzschild black-hole spacetime and obtain the angular position and magnification of the relativistic images. Supposing that the gravitational field of the supermassive central object of the galaxy can be described by this metric, we estimate the numerical values of the coefficients and observables for strong gravitational lensing. In comparison to the Reissner-Norström black hole, we find that the influences of the spacetime noncommutative parameter is similar to those of the charge, but these influences are much smaller. This may offer a way to distinguish a noncommutative black hole from a Reissner-Norström black hole, and may permit us to probe the spacetime noncommutative constant ϑ by the astronomical instruments in the future.

  3. Analysis of luminosity distributions and the shape parameters of strong gravitational lensing elliptical galaxies

    NASA Astrophysics Data System (ADS)

    Biernaux, J.; Magain, P.; Sluse, D.; Chantry, V.

    2016-01-01

    Context. The luminosity profiles of galaxies acting as strong gravitational lenses can be tricky to study. Indeed, strong gravitational lensing images display several lensed components, both point-like and diffuse, around the lensing galaxy. Those objects limit the study of the galaxy luminosity to its inner parts. Therefore, the usual fitting methods perform rather badly on such images. Previous studies of strong lenses luminosity profiles using software such as GALFIT or IMFITFITS and various PSF-determining methods have resulted in somewhat discrepant results. Aims: The present work aims at investigating the causes of those discrepancies, as well as at designing more robust techniques for studying the morphology of early-type lensing galaxies with the ability to subtract a lensed signal from their luminosity profiles. Methods: We design a new method to independently measure each shape parameter, namely, the position angle, ellipticity, and half-light radius of the galaxy. Our half-light radius measurement method is based on an innovative scheme for computing isophotes that is well suited to measuring the morphological properties of gravititational lensing galaxies. Its robustness regarding various specific aspects of gravitational lensing image processing is analysed and tested against GALFIT. It is then applied to a sample of systems from the CASTLES database. Results: Simulations show that, when restricted to small, inner parts of the lensing galaxy, the technique presented here is more trustworthy than GALFIT. It gives more robust results than GALFIT, which shows instabilities regarding the fitting region, the value of the Sérsic index, and the signal-to-noise ratio. It is therefore better suited than GALFIT for gravitational lensing galaxies. It is also able to study lensing galaxies that are not much larger than the PSF. New values for the half-light radius of the objects in our sample are presented and compared to previous works. Table 6 is only available

  4. Strong gravitational lensing with Gauss-Bonnet correction

    SciTech Connect

    Sadeghi, J.; Vaez, H. E-mail: h.vaez@umz.ac.ir

    2014-06-01

    In this paper we investigate the strong gravitational lensing in a five dimensional background with Gauss-Bonnet gravity, so that in 4-dimensions the Gauss-Bonnet correction disappears. By considering the logarithmic term for deflection angle, we obtain the deflection angle α-circumflex and corresponding parameters ā and b-bar . Finally, we estimate some properties of relativistic images such as θ{sub ∞}, s and r{sub m}.

  5. Strong lensing in the inner halo of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Saez, C.; Campusano, L. E.; Cypriano, E. S.; Sodré, L.; Kneib, J.-P.

    2016-08-01

    We present an axially symmetric formula to calculate the probability of finding gravitational arcs in galaxy clusters, being induced by their massive dark matter haloes, as a function of clusters redshifts and virial masses. The formula includes the ellipticity of the clusters dark matter potential by using a pseudo-elliptical approximation. The probabilities are calculated and compared for two dark matter halo profiles, the Navarro, Frenk and White (NFW) and the non-singular-isothermal-sphere (NSIS). We demonstrate the power of our formulation through a Kolmogorov-Smirnov (KS) test on the strong lensing statistics of an X-ray bright sample of low-redshift Abell clusters. This KS test allows us to establish limits on the values of the concentration parameter for the NFW profile (c_Δ) and the core radius for the NSIS profile (rc), which are related to the lowest cluster redshift (zcut) where strong arcs can be observed. For NFW dark matter profiles, we infer cluster haloes with concentrations that are consistent to those predicted by ΛCDM simulations. As for NSIS dark matter profiles, we find only upper limits for the clusters core radii and thus do not rule out a purely SIS model. For alternative mass profiles, our formulation provides constraints through zcut on the parameters that control the concentration of mass in the inner region of the clusters haloes. We find that zcut is expected to lie in the 0.0-0.2 redshift, highlighting the need to include very low-z clusters in samples to study the clusters mass profiles.

  6. Strong field gravitational lensing by a charged Galileon black hole

    NASA Astrophysics Data System (ADS)

    Zhao, Shan-Shan; Xie, Yi

    2016-07-01

    Strong field gravitational lensings are dramatically disparate from those in the weak field by representing relativistic images due to light winds one to infinity loops around a lens before escaping. We study such a lensing caused by a charged Galileon black hole, which is expected to have possibility to evade no-hair theorem. We calculate the angular separations and time delays between different relativistic images of the charged Galileon black hole. All these observables can potentially be used to discriminate a charged Galileon black hole from others. We estimate the magnitudes of these observables for the closest supermassive black hole Sgr A*. The strong field lensing observables of the charged Galileon black hole can be close to those of a tidal Reissner-Nordström black hole or those of a Reissner-Nordström black hole. It will be helpful to distinguish these black holes if we can separate the outermost relativistic images and determine their angular separation, brightness difference and time delay, although it requires techniques beyond the current limit.

  7. Model-independent characterisation of strong gravitational lenses

    NASA Astrophysics Data System (ADS)

    Wagner, J.; Bartelmann, M.

    2016-05-01

    We develop a new approach to extracting model-independent information from observations of strong gravitational lenses. The approach is based on the generic properties of images near the fold and cusp catastrophes in caustics and critical curves. The observables we used are the relative image positions, the magnification ratios and ellipticities of extended images, and time delays between images with temporally varying intensity. We show how these observables constrain derivatives and ratios of derivatives of the lensing potential near a critical curve. Based on these measured properties of the lensing potential, classes of parametric lens models can then easily be restricted to the parameter values that are compatible with the measurements, thus allowing fast scans of a large variety of models. Applying our approach to a representative galaxy (JVAS B1422+231) and a galaxy-cluster lens (MACS J1149.5+2223), we show which model-independent information can be extracted in each case and demonstrate that the parameters obtained by our approach for known parametric lens models agree well with those found by detailed model fitting.

  8. Strong Gravitational Lensing Insights into Dark Matter Physics

    NASA Astrophysics Data System (ADS)

    Moustakas, Leonidas A.; Keeton, C. R.; Sigurdson, K. R.; Cyr-Racine, F.; Fadely, R.; Dobler, G.; Marshall, P. J.; OMEGA Explorer Science Team

    2013-01-01

    The thermal or interaction properties of dark matter are expected to lead to different levels of sub-galactic structure within Milky-Way scale galaxies. Through observations of galaxies acting as strong gravitational lenses, it is possible to statistically map the details of these structures. In recent theoretical and simulation work examined through Importance Sampling approaches, we demonstrate how efficiently dark matter substructures can be statistically constrained through select ground- and space-based measurements, and map out forecasts for how well possible Hubble Space Telescope and possible future space based experiments may perform.

  9. Measuring angular diameter distances of strong gravitational lenses

    NASA Astrophysics Data System (ADS)

    Jee, I.; Komatsu, E.; Suyu, S. H.

    2015-11-01

    The distance-redshift relation plays a fundamental role in constraining cosmological models. In this paper, we show that measurements of positions and time delays of strongly lensed images of a background galaxy, as well as those of the velocity dispersion and mass profile of a lens galaxy, can be combined to extract the angular diameter distance of the lens galaxy. Physically, as the velocity dispersion and the time delay give a gravitational potential (GM/r) and a mass (GM) of the lens, respectively, dividing them gives a physical size (r) of the lens. Comparing the physical size with the image positions of a lensed galaxy gives the angular diameter distance to the lens. A mismatch between the exact locations at which these measurements are made can be corrected by measuring a local slope of the mass profile. We expand on the original idea put forward by Paraficz and Hjorth, who analyzed singular isothermal lenses, by allowing for an arbitrary slope of a power-law spherical mass density profile, an external convergence, and an anisotropic velocity dispersion. We find that the effect of external convergence cancels out when dividing the time delays and velocity dispersion measurements. We derive a formula for the uncertainty in the angular diameter distance in terms of the uncertainties in the observables. As an application, we use two existing strong lens systems, B1608+656 (zL=0.6304) and RXJ1131-1231 (zL=0.295), to show that the uncertainty in the inferred angular diameter distances is dominated by that in the velocity dispersion, σ2, and its anisotropy. We find that the current data on these systems should yield about 16% uncertainty in DA per object. This improves to 13% when we measure σ2 at the so-called sweet-spot radius. Achieving 7% is possible if we can determine σ2 with 5% precision.

  10. Next generation strong lensing time delay estimation with Gaussian processes

    NASA Astrophysics Data System (ADS)

    Hojjati, Alireza; Linder, Eric V.

    2014-12-01

    Strong gravitational lensing forms multiple, time delayed images of cosmological sources, with the "focal length" of the lens serving as a cosmological distance probe. Robust estimation of the time delay distance can tightly constrain the Hubble constant as well as the matter density and dark energy. Current and next generation surveys will find hundreds to thousands of lensed systems but accurate time delay estimation from noisy, gappy light curves is potentially a limiting systematic. Using a large sample of blinded light curves from the Strong Lens Time Delay Challenge we develop and demonstrate a Gaussian process cross correlation technique that delivers an average bias within 0.1% depending on the sampling, necessary for subpercent Hubble constant determination. The fits are accurate (80% of them within one day) for delays from 5-100 days and robust against cadence variations shorter than six days. We study the effects of survey characteristics such as cadence, season, and campaign length, and derive requirements for time delay cosmology: in order not to bias the cosmology determination by 0.5 σ , the mean time delay fit accuracy must be better than 0.2%.

  11. Probing dark matter halos with strong gravitational lensing

    NASA Astrophysics Data System (ADS)

    Ferreras, Ignacio

    2015-08-01

    Strong gravitational lensing over galaxy scales allows us to explore dark matter halos and their connection with the luminous component. In this talk we present recent work on a sample extracted from the SLACS dataset, where the spectroscopic information from SDSS allows us to study the effect of a non-universal initial mass function on the stellar mass-to-light ratio. In addition, by studying galaxies where the background source probes the central part of the lens, we can derive significant constraints on the properties of the dark matter halo. This is one of the few observational methods that can be used to contrast with the standard concentration-virial mass relationships proposed by numerical simulations.

  12. Three Gravitational Lenses for the Price of One: Enhanced Strong Lensing Through Galaxy Clustering

    SciTech Connect

    Fassnacht, Chris D.; McKean, J.P.; Koopmans, L.V.E.; Treu, T.; Blandford, R.D.; Auger, M.W.; Jeltema, T.E.; Lubin, L.M.; Margoniner, V.E.; Wittman, D.; /UC, Davis /Kapteyn Astron. Inst., Groningen /UC, Santa Barbara /KIPAC, Menlo Park /Carnegie Inst. Observ.

    2006-04-03

    We report the serendipitous discovery of two strong gravitational lens candidates (ACS J160919+6532 and ACS J160910+6532) in deep images obtained with the Advanced Camera for Surveys on the Hubble Space Telescope, each less than 40'' from the previously known gravitational lens system CLASS B1608+656. The redshifts of both lens galaxies have been measured with Keck and Gemini: one is a member of a small galaxy group at z {approx} 0.63, which also includes the lensing galaxy in the B1608+656 system, and the second is a member of a foreground group at z {approx} 0.43. By measuring the effective radii and surface brightnesses of the two lens galaxies, we infer their velocity dispersions based on the passively evolving Fundamental Plane (FP) relation. Elliptical isothermal lens mass models are able to explain their image configurations within the lens hypothesis, with a velocity dispersion compatible with that estimated from the FP for a reasonable source-redshift range. Based on the large number of massive early-type galaxies in the field and the number-density of faint blue galaxies, the presence of two additional lens systems around CLASS B1608+656 is not unlikely in hindsight. Gravitational lens galaxies are predominantly early-type galaxies, which are clustered, and the lensed quasar host galaxies are also clustered. Therefore, obtaining deep high-resolution images of the fields around known strong lens systems is an excellent method of enhancing the probability of finding additional strong gravitational lens systems.

  13. Digital holographic testing of biconvex lenses.

    PubMed

    Chhaniwal, V K; Kihiko, J M; Dubey, S; Shearon, G; Javidi, B; Anand, A

    2013-12-20

    Lenses are one of the most important optical elements for manipulation of wavefronts. For their proper selection, the wavefronts produced by the lenses should be analyzed. Digital holography is a tool which provides whole-field reconstructions of wavefronts, and here the use of digital holographic interferometry in complete characterization of wavefronts from lenses is investigated. Digital holograms of the wavefront from the test lens are recorded for various positions of the test lens from a point source. The reconstructed phase of the wavefront from the test lens is compared with a digitally inputted wavefront for measurement of parallelism as well as curvature. The focal length of the test lens is computed by measuring the change in curvature of the wavefront for two positions of the test lens. The radius of curvature of the test lens is determined by using the test lens in the reflection mode. Refractive index of the lens material is also determined using this method. Detailed theoretical and experimental analysis is provided. PMID:24513936

  14. The SDSS Discovery of a Strongly Lensed Post-Starburst Galaxy at z=0.766

    SciTech Connect

    Shin, Min-Su; Strauss, Michael A.; Oguri, Masamune; Inada, Naohisa; Falco, Emilio E.; Broadhurst, Tom; Gunn, James E.

    2008-09-30

    We present the first result of a survey for strong galaxy-galaxy lenses in Sloan Digital Sky Survey (SDSS) images. SDSS J082728.70+223256.4 was selected as a lensing candidate using selection criteria based on the color and positions of objects in the SDSS photometric catalog. Follow-up imaging and spectroscopy showed this object to be a lensing system. The lensing galaxy is an elliptical at z = 0.349 in a galaxy cluster. The lensed galaxy has the spectrum of a post-starburst galaxy at z = 0.766. The lensing galaxy has an estimated mass of {approx} 1.2 x 10{sup 12} M{sub {circle_dot}} and the corresponding mass to light ratio in the B-band is {approx} 26 M{sub {circle_dot}}/L{sub {circle_dot}} inside 1.1 effective radii of the lensing galaxy. Our study shows how catalogs drawn from multi-band surveys can be used to find strong galaxy-galaxy lenses having multiple lens images. Our strong lensing candidate selection based on photometry-only catalogs will be useful in future multi-band imaging surveys such as SNAP and LSST.

  15. Resolving high energy emission of jets using strong gravitational lensing

    NASA Astrophysics Data System (ADS)

    Barnacka, Anna

    2014-11-01

    Chandra observations of M87 in 2004 uncovered an outburst originating in distant knot along the jet hundreds of parsecs from the core. This discovery challenges our understanding of the origin of high energy flares. Current technology is inadequate to resolve jets at distances greater than M87, or observed at higher energies. We propose to use gravitationally lensed jets to investigate the structure of more distant sources. Photons emitted at different sites cross the lens plane at different distances, thus magnification ratios and time delays differ between the mirage images. Monitoring of flares from lensed jets reveals the origin of the emission. With detectors like Chandra, lensed systems are a tool for resolving the structure of the jets and for investigating their cosmic evolution.

  16. An Imaging and Spectroscopic Survey of Bright Strongly-Lensed Galaxies in the SDSS

    NASA Astrophysics Data System (ADS)

    Buckley-Geer, Elizabeth; Lin, Huan; Allam, Sahar; Kubo, Jeff; Diehl, Tom; Tucker, Douglas; Kubik, Donna; Annis, Jim

    2009-02-01

    We propose for WIYN imaging and Mayall spectroscopic follow-up for a sample of 21 very bright, candidate strong lensing systems from the Sloan Digital Sky Survey (SDSS), found as part of our systematic search for potentially lensed bright blue arcs and knots around luminous red galaxies from the SDSS. Our survey has already spectroscopically confirmed 12 strong lensing systems, including 6 among the brightest lensed Lyman break galaxies known at z > 2, including the ``8 o'clock arc.'' We will take advantage of the excellent WIYN image quality to obtain gri color data vital to derive optimal lensing models for our systems, and we also take advantage of the brightness of our lensed galaxies, whose redshifts may be efficiently measured on the Mayall 4m. Overall, we expect to compile a final sample of order 30 spectroscopically confirmed SDSS lensing systems, a large data set which allows us to expand our ongoing follow-up studies of the physical properties of individual bright lensed star-forming galaxies at high redshifts z ~ 1-3. Moreover, this larger sample allows us to better constrain the mass distributions of the group/cluster environments around our z ~ 0.4 red lens galaxies, in a 3''-10'' Einstein radius regime that is complementary to the smaller single- galaxy and larger galaxy-cluster scales probed by other SDSS strong lens data sets.

  17. A concentric telescopic meniscus for testing underwater lenses.

    PubMed

    Mandler, W

    1970-03-01

    In addition to being inconvenient, testing underwater lenses in their normal environment involves the difficulty of differentiating between the effects caused by the photographic system and those caused by the turbidity of the water. The principles developed and practical devices illustrated show that it is possible to apply all test methods for common photographic lenses to underwater lenses with a correctly designed concentric telescopic meniscus. PMID:20076276

  18. Research and analysis on new test lenses for calibration of focimeters used for measuring contact lenses

    NASA Astrophysics Data System (ADS)

    Zhang, Jiyan; Wang, Liru; Ma, Zhenya

    2006-11-01

    A focimeter is one of the basic ophthalmic instruments used in every optometric practice, and verification of the accuracy and calibration of the instrument are of the utmost importance. For many years the International Standardization for Organization requires that calibrations for all kinds of focimeters shall be accomplished by using test lenses described in ISO 9342:1996. These test lenses must be of high quality and of nominal back vertex power that is known with high accuracy. With the development of science and technology, ISO 9342 was revised in 2005. A new part ISO 9342-2 had been drafted for test lenses used to calibrate focimeters with contact lens measurement, and the original ISO 9342 was turned into the current ISO 9342-1, which could only be used to calibrate fociemters with spectacle lens measurement. As one of the standard drafters, the background for the newly published ISO 9342-2 is introduced in this study, and comparison between test lenses of ISO 9342-1 and ISO 9342-2 is made. Further, the influence of tolerance and uncertainty in design and production of standard test lenses of ISO 9342-2 is analyzed. The paraxial approximation is used to relate the lens parameters with back vertex power and to calculate the uncertainty budget. Moreover, one set of test lenses conforming to ISO 9342-2 is manufactured and experiments are done with it. Results show that test lenses described in ISO 9342-2 can correct the measurement errors of focimeters used for measuring contact lenses well, especially for spherical aberration, and the correction is more effective for spherical contact lenses with high back vertex power.

  19. Strong gravitational lensing of gravitational waves in Einstein Telescope

    SciTech Connect

    Piórkowska, Aleksandra; Biesiada, Marek; Zhu, Zong-Hong E-mail: marek.biesiada@us.edu.pl

    2013-10-01

    Gravitational wave experiments have entered a new stage which gets us closer to the opening a new observational window on the Universe. In particular, the Einstein Telescope (ET) is designed to have a fantastic sensitivity that will provide with tens or hundreds of thousand NS-NS inspiral events per year up to the redshift z = 2. Some of such events should be gravitationally lensed by intervening galaxies. We explore the prospects of observing gravitationally lensed inspiral NS-NS events in the Einstein telescope. Being conservative we consider the lens population of elliptical galaxies. It turns out that depending on the local insipral rate ET should detect from one per decade detection in the pessimistic case to a tens of detections per year for the most optimistic case. The detection of gravitationally lensed source in gravitational wave detectors would be an invaluable source of information concerning cosmography, complementary to standard ones (like supernovae or BAO) independent of the local cosmic distance ladder calibrations.

  20. SIZE BIAS AND DIFFERENTIAL LENSING OF STRONGLY LENSED, DUSTY GALAXIES IDENTIFIED IN WIDE-FIELD SURVEYS

    SciTech Connect

    Hezaveh, Yashar D.; Holder, Gilbert P.; Marrone, Daniel P.

    2012-12-10

    We address two selection effects that operate on samples of gravitationally lensed dusty galaxies identified in millimeter- and submillimeter-wavelength surveys. First, we point out the existence of a ''size bias'' in such samples: due to finite source effects, sources with higher observed fluxes are increasingly biased toward more compact objects. Second, we examine the effect of differential lensing in individual lens systems by modeling each source as a compact core embedded in an extended diffuse halo. Considering the ratio of magnifications in these two components, we find that at high overall magnifications, the compact component is amplified by a much larger factor than the diffuse component, but at intermediate magnifications ({approx}10) the probability of a larger magnification for the extended region is higher. Lens models determined from multi-frequency resolved imaging data are crucial to correct for this effect.

  1. GALAXY SCALE LENSES IN THE RCS2. I. FIRST CATALOG OF CANDIDATE STRONG LENSES

    SciTech Connect

    Anguita, T.; Barrientos, L. F.; Gladders, M. D.; Faure, C.; Yee, H. K. C.; Gilbank, D. G.

    2012-04-01

    We present the first galaxy scale lens catalog from the second Red-Sequence Cluster Survey. The catalog contains 60 lensing system candidates comprised of Luminous Red Galaxy (LRG) lenses at 0.2 {approx}< z {approx}< 0.5 surrounded by blue arcs or apparent multiple images of background sources. The catalog is a valuable complement to previous galaxy-galaxy lens catalogs as it samples an intermediate lens redshift range and is composed of bright sources and lenses that allow easy follow-up for detailed analysis. Mass and mass-to-light ratio estimates reveal that the lens galaxies are massive ( M-bar {approx} 5.5 Multiplication-Sign 10{sup 11} [M{sub Sun} h{sup -1}]) and rich in dark matter (M/L-bar{approx} 14 [M{sub Sun }/L{sub Sun ,B} h]). Even though a slight increasing trend in the mass-to-light ratio is observed from z = 0.2 to z = 0.5, current redshift and light profile measurements do not allow stringent constraints on the mass-to-light ratio evolution of LRGs.

  2. The Sloan Bright Arcs Survey : Six Strongly Lensed Galaxies at z=0.4-1.4

    SciTech Connect

    Kubo, Jeffrey M.; Allam, Sahar S.; Annis, James; Buckley-Geer, Elizabeth J.; Diehl, H.Thomas; Kubik, Donna; Lin, Huan; Tucker, Douglas; /Fermilab

    2008-12-01

    We present new results of our program to systematically search for strongly lensed galaxies in the Sloan Digital Sky Survey (SDSS) imaging data. In this study six strong lens systems are presented which we have confirmed with followup spectroscopy and imaging using the 3.5m telescope at the Apache Point Observatory. Preliminary mass models indicate that the lenses are group-scale systems with velocity dispersions ranging from 466?878 km s{sup -1} at z = 0.17-0.45 which are strongly lensing source galaxies at z = 0.4-1.4. Galaxy groups are a relatively new mass scale just beginning to be probed with strong lensing. Our sample of lenses roughly doubles the confirmed number of group-scale lenses in the SDSS and complements ongoing strong lens searches in other imaging surveys such as the CFHTLS (Cabanac et al. 2007). As our arcs were discovered in the SDSS imaging data they are all bright (r {approx_equal} 22), making them ideally suited for detailed follow-up studies.

  3. UP TO 100,000 RELIABLE STRONG GRAVITATIONAL LENSES IN FUTURE DARK ENERGY EXPERIMENTS

    SciTech Connect

    Serjeant, S.

    2014-09-20

    The Euclid space telescope will observe ∼10{sup 5} strong galaxy-galaxy gravitational lens events in its wide field imaging survey over around half the sky, but identifying the gravitational lenses from their observed morphologies requires solving the difficult problem of reliably separating the lensed sources from contaminant populations, such as tidal tails, as well as presenting challenges for spectroscopic follow-up redshift campaigns. Here I present alternative selection techniques for strong gravitational lenses in both Euclid and the Square Kilometre Array, exploiting the strong magnification bias present in the steep end of the Hα luminosity function and the H I mass function. Around 10{sup 3} strong lensing events are detectable with this method in the Euclid wide survey. While only ∼1% of the total haul of Euclid lenses, this sample has ∼100% reliability, known source redshifts, high signal-to-noise, and a magnification-based selection independent of assumptions of lens morphology. With the proposed Square Kilometre Array dark energy survey, the numbers of reliable strong gravitational lenses with source redshifts can reach 10{sup 5}.

  4. Cosmological Studies with Galaxy Clusters, Active Galactic Nuclei, and Strongly Lensed Quasars

    NASA Astrophysics Data System (ADS)

    Rumbaugh, Nicholas Andrew

    transitional `green valley' on a color-magnitude diagram. Spectral analysis of the AGN hosts showed that the average host galaxy had either on-going or recent star formation, and was younger than the average galaxy, across all LSS in our sample. We further subdivided our sample in two based on the average evolutionary state of the LSS. The AGN in the more evolved structures had lower X-ray luminosities and longer times since last starburst. These results provide some evidence for merger-based AGN triggering, although other mechanisms, and possibly more than one, could be responsible. In the third study, we probed LambdaCDM cosmology from a different angle. An important part of the model is the cosmological parameters that define our universe. As such, probes that can more accurately and precisely measure these parameters, such as H0 and the dark energy equation of state, w, can allow us to more closely inspect the model. Strongly-lensed quasars provide one such probe, and we sought to perform the first step in using them for cosmological inference, which is to measure the time delays between strongly lensed images. We performed radio monitoring campaigns on six strongly lensed quasars using the Very Large Array. Lightcurves were extracted for each lensed image and analyzed for intrinsic variability. Two lensed quasars showed strong time variations, but the variations were linear in time, preventing precise time delay measurements due to a degeneracy with the magnifications. These results suggest most of the systems should be targeted for followup monitoring, and we estimate that time delays can be measured for the most variable systems with precision of 0.5 to 3.5 days with two more seasons of monitoring. In a joint fit with previously studied systems, these measurements could tighten constraints on H 0 by up to ~1.4.

  5. Constraining Horava-Lifshitz gravity by weak and strong gravitational lensing

    SciTech Connect

    Horvath, Zsolt; Gergely, Laszlo A.; Keresztes, Zoltan; Harko, Tiberiu; Lobo, Francisco S. N.

    2011-10-15

    We discuss gravitational lensing in the Kehagias-Sfetsos space-time emerging in the framework of Horava-Lifshitz gravity. In weak lensing, we show that there are three regimes, depending on the value of {lambda}=1/{omega}d{sup 2}, where {omega} is the Horava-Lifshitz parameter and d characterizes the lensing geometry. When {lambda} is close to zero, light deflection typically produces two images, as in Schwarzschild lensing. For very large {lambda}, the space-time approaches flatness, therefore there is only one undeflected image. In the intermediate range of {lambda}, only the upper focused image is produced due to the existence of a maximal deflection angle {delta}{sub max}, a feature inexistent in the Schwarzschild weak lensing. We also discuss the location of Einstein rings, and determine the range of the Horava-Lifshitz parameter compatible with present-day lensing observations. Finally, we analyze in the strong lensing regime the first two relativistic Einstein rings and determine the constraints on the parameter range to be imposed by forthcoming experiments.

  6. The Population of Galaxy-Galaxy Strong Lenses in Forthcoming Optical Imaging Surveys

    NASA Astrophysics Data System (ADS)

    Collett, Thomas E.

    2015-09-01

    Ongoing and future imaging surveys represent significant improvements in depth, area, and seeing compared to current data sets. These improvements offer the opportunity to discover up to three orders of magnitude more galaxy-galaxy strong lenses than are currently known. In this work we forecast the number of lenses that will be discoverable in forthcoming surveys and simulate their properties. We generate a population of statistically realistic strong lenses and simulate observations of this population for the Dark Energy Survey (DES), the Large Synoptic Survey Telescope (LSST), and Euclid surveys. We verify our model against the galaxy-scale lens search of the Canada-France-Hawaii Telescope Legacy Survey, predicting 250 discoverable lenses compared to 220 found by Gavazzi et al. The predicted Einstein radius distribution is also remarkably similar to that found by Sonnenfeld et al. For future surveys we find that, assuming Poisson limited lens galaxy subtraction, searches of the DES, LSST, and Euclid data sets should discover 2400, 120000, and 170000 galaxy-galaxy strong lenses, respectively. Finders using blue-minus-red (g-i) difference imaging for lens subtraction can discover 1300 and 62000 lenses in DES and LSST. The uncertainties on the model are dominated by the high-redshift source population, which typically gives fractional errors on the discoverable lens number at the level of tens of percent. We find that doubling the signal-to-noise ratio required for a lens to be detectable approximately halves the number of detectable lenses in each survey, indicating the importance of understanding the selection function and the sensitivity of future lens finders in interpreting strong lens statistics. We make our population forecasting and simulated observation codes publicly available so that the selection function of strong lens finders can easily be calibrated.

  7. Source-position transformation: an approximate invariance in strong gravitational lensing

    NASA Astrophysics Data System (ADS)

    Schneider, Peter; Sluse, Dominique

    2014-04-01

    The main obstacle that gravitational lensing has in determining accurate masses of deflectors, or in determining precise estimates for the Hubble constant, is the degeneracy of lensing observables with respect to the mass-sheet transformation (MST). The MST is a global modification of the mass distribution which leaves all image positions, shapes, and flux ratios invariant, but which changes the time delay. Here we show that another global transformation of lensing mass distributions exists which leaves image positions and flux ratios almost invariant, and of which the MST is a special case. As is the case for the MST, this new transformation only applies if one considers only those source components that are at the same distance from us. Whereas for axi-symmetric lenses this source position transformation exactly reproduces all strong lensing observables, it does so only approximately for more general lens situations. We provide crude estimates for the accuracy with which the transformed mass distribution can reproduce the same image positions as the original lens model, and present an illustrative example of its performance. This new invariance transformation is most likely the reason why the same strong lensing information can be accounted for with rather different mass models.

  8. THE CFHTLS-STRONG LENSING LEGACY SURVEY (SL2S): INVESTIGATING THE GROUP-SCALE LENSES WITH THE SARCS SAMPLE

    SciTech Connect

    More, A.; More, S.; Cabanac, R.; Alard, C.; Gavazzi, R.; Limousin, M.; Kneib, J-P.; Motta, V.

    2012-04-10

    We present the Strong Lensing Legacy Survey-ARCS (SARCS) sample compiled from the final T0006 data release of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) covering a total non-overlapping area of 159 deg{sup 2}. We adopt a semi-automatic method to find gravitational arcs in the survey that makes use of an arc-finding algorithm. The candidate list is pruned by visual inspection and ranking to form the final SARCS sample. This list also includes some serendipitously discovered lens candidates which the automated algorithm did not detect. The SARCS sample consists of 127 lens candidates which span arc radii {approx}2''-18'' within the unmasked area of {approx}150 deg{sup 2}. Within the sample, 54 systems are promising lenses among which, we find 12 giant arcs (length-to-width ratio {>=}8). We also find two radial arc candidates in SL2SJ141447+544704. From our sample, we detect a systematic alignment of the giant arcs with the major axis of the baryonic component of the putative lens in concordance with previous studies. This alignment is also observed for all arcs in the sample and does not vary significantly with increasing arc radius. The mean values of the photometric redshift distributions of lenses corresponding to the giant arcs and all arcs sample are at z {approx} 0.6. Owing to the large area and depth of the CFHTLS, we find the largest sample of lenses probing mass scales that are intermediate to cluster and galaxy lenses for the first time. We compare the observed image separation distribution (ISD) of our arcs with theoretical models. A two-component density profile for the lenses which accounts for both the central galaxy and the dark matter component is required by the data to explain the observed ISD. Unfortunately, current levels of uncertainties and degeneracies accommodate models both with and without adiabatic contraction. We also show the effects of changing parameters of the model that predict the ISD and that a larger lens sample

  9. GEMINI/GMOS SPECTROSCOPY OF 26 STRONG-LENSING-SELECTED GALAXY CLUSTER CORES

    SciTech Connect

    Bayliss, Matthew B.; Gladders, Michael D.; Koester, Benjamin P.; Hennawi, Joseph F.; Sharon, Keren; Dahle, Haakon; Oguri, Masamune

    2011-03-15

    We present results from a spectroscopic program targeting 26 strong-lensing cluster cores that were visually identified in the Sloan Digital Sky Survey (SDSS) and the Second Red-Sequence Cluster Survey (RCS-2). The 26 galaxy cluster lenses span a redshift range of 0.2 < z < 0.65, and our spectroscopy reveals 69 unique background sources with redshifts as high as z = 5.200. We also identify redshifts for 262 cluster member galaxies and measure the velocity dispersions and dynamical masses for 18 clusters where we have redshifts for N {>=} 10 cluster member galaxies. We account for the expected biases in dynamical masses of strong-lensing-selected clusters as predicted by results from numerical simulations and discuss possible sources of bias in our observations. The median dynamical mass of the 18 clusters with N {>=} 10 spectroscopic cluster members is M {sub Vir} = 7.84 x 10{sup 14} M {sub sun} h {sup -1} {sub 0.7}, which is somewhat higher than predictions for strong-lensing-selected clusters in simulations. The disagreement is not significant considering the large uncertainty in our dynamical data, systematic uncertainties in the velocity dispersion calibration, and limitations of the theoretical modeling. Nevertheless our study represents an important first step toward characterizing large samples of clusters that are identified in a systematic way as systems exhibiting dramatic strong-lensing features.

  10. Stellar and dust properties of strongly lensed z~1.5-3 star forming galaxies from the Herschel Lensing Survey

    NASA Astrophysics Data System (ADS)

    Sklias, Panos; Schaerer, Daniel; Dessauges-Zavadsky, Miroslava

    2015-08-01

    Understanding and constraining the early cosmic star formation history of the Universe is a key question of galaxy evolution. In the IR, deep surveys are limited by instrumentation/confusion, so gravitational lensing is a potent tool to probe lower luminosities than detectable in blank fields at redshifts above 1.Utilizing the multi-wavelength photometry (optical to IR/submm) from the Herschel Lensing Survey, we perform SED fitting with different variable star formation histories (SFHs) on a small sample of strongly lensed star forming galaxies at z~1.5-3. Although in general SED modeling of dust obscured galaxies is affected by degeneracies (eg., in age-extinction), we reduce them by imposing energy conservation, i.e. by constraining the dust attenuation thanks to the observed IR luminosities.In order to mitigate the small number statistics, we also apply our method on a larger sample from GOODS-Herschel, and explore its effects on physical parameter determination and extent of applicability.Thanks to lensing, we have robust detections of faint sources below the usual confusion limits of the observing instruments, and thus can characterize the properties of normal star-forming galaxies at epochs surrounding the peak of the cosmic star formation history. We constrain the IR luminosities of sources down to 1011 Lsun, estimate dust masses and temperatures, as well as stellar properties. The IR and - when available - nebular emission observations allow us to discriminate between SFHs, and between starbursts, post-starbursts and Main Sequence galaxies. This is illustrated specifically with for the well known galaxy nicknamed the «Cosmic Eye». We observe that most of our sources have warmer dust temperature that low-z galaxies in the same luminosity range. They are comparable to temperatures of bright IR galaxies at high-z, indicative that there is a general rising trend of temperature with redshift, due to the more intensively star-forming environment at earlier

  11. Strong gravitational lensing of gravitational waves from double compact binaries—perspectives for the Einstein Telescope

    SciTech Connect

    Biesiada, Marek; Ding, Xuheng; Zhu, Zong-Hong; Piórkowska, Aleksandra E-mail: dingxuheng@mail.bnu.edu.cn E-mail: zhuzh@bnu.edu.cn

    2014-10-01

    Gravitational wave (GW) experiments are entering their advanced stage which should soon open a new observational window on the Universe. Looking into this future, the Einstein Telescope (ET) was designed to have a fantastic sensitivity improving significantly over the advanced GW detectors. One of the most important astrophysical GW sources supposed to be detected by the ET in large numbers are double compact objects (DCO) and some of such events should be gravitationally lensed by intervening galaxies. We explore the prospects of observing gravitationally lensed inspiral DCO events in the ET. This analysis is a significant extension of our previous paper [1]. We are using the intrinsic merger rates of the whole class of DCO (NS-NS,BH-NS,BH-BH) located at different redshifts as calculated by [2] by using StarTrack population synthesis evolutionary code. We discuss in details predictions from each evolutionary scenario. Our general conclusion is that ET would register about 50–100 strongly lensed inspiral events per year. Only the scenario in which nascent BHs receive strong kick gives the predictions of a few events per year. Such lensed events would be dominated by the BH-BH merging binary systems. Our results suggest that during a few years of successful operation ET will provide a considerable catalog of strongly lensed events.

  12. Gravitational Lensing in the Strong Field Limit for Kar's Metric

    NASA Astrophysics Data System (ADS)

    Benavides, Carlos A.; Cárdenas-Avendaño, Alejandro; Larranaga, Alexis

    2016-04-01

    In this paper we calculate the strong field limit deflection angle for a light ray passing near a scalar charged spherically symmetric object, described by a metric which comes from the low-energy limit of heterotic string theory. Then, we compare the expansion parameters of our results with those obtained in the Einstein's canonical frame, obtained by a conformal transformation, and we show that, at least at first order, the results do not agree.

  13. HERSCHEL-ATLAS: TOWARD A SAMPLE OF {approx}1000 STRONGLY LENSED GALAXIES

    SciTech Connect

    Gonzalez-Nuevo, J.; Lapi, A.; Bressan, S.; Danese, L.; De Zotti, G.; Cai, Z.-Y.; Fan, L.; Fleuren, S.; Sutherland, W.; Negrello, M.; Baes, M.; Baker, A. J.; Clements, D. L.; Cooray, A.; Dannerbauer, H.; Dunne, L.; Dye, S.; Eales, S.; Frayer, D. T.; Harris, A. I.; and others

    2012-04-10

    While the selection of strongly lensed galaxies (SLGs) with 500 {mu}m flux density S{sub 500} > 100 mJy has proven to be rather straightforward, for many applications it is important to analyze samples larger than the ones obtained when confining ourselves to such a bright limit. Moreover, only by probing to fainter flux densities is it possible to exploit strong lensing to investigate the bulk of the high-z star-forming galaxy population. We describe HALOS (the Herschel-ATLAS Lensed Objects Selection), a method for efficiently selecting fainter candidate SLGs, reaching a surface density of {approx_equal} 1.5-2 deg{sup -2}, i.e., a factor of about 4-6 higher than that at the 100 mJy flux limit. HALOS will allow the selection of up to {approx}1000 candidate SLGs (with amplifications {mu} {approx}> 2) over the full H-ATLAS survey area. Applying HALOS to the H-ATLAS Science Demonstration Phase field ({approx_equal} 14.4 deg{sup 2}) we find 31 candidate SLGs, whose candidate lenses are identified in the VIKING near-infrared catalog. Using the available information on candidate sources and candidate lenses we tentatively estimate a {approx_equal} 72% purity of the sample. As expected, the purity decreases with decreasing flux density of the sources and with increasing angular separation between candidate sources and lenses. The redshift distribution of the candidate lensed sources is close to that reported for most previous surveys for lensed galaxies, while that of candidate lenses extends to redshifts substantially higher than found in the other surveys. The counts of candidate SLGs are also in good agreement with model predictions. Even though a key ingredient of the method is the deep near-infrared VIKING photometry, we show that H-ATLAS data alone allow the selection of a similarly deep sample of candidate SLGs with an efficiency close to 50%; a slightly lower surface density ({approx_equal} 1.45 deg{sup -2}) can be reached with a {approx}70% efficiency.

  14. Galaxy density profiles and shapes - II. Selection biases in strong lensing surveys

    NASA Astrophysics Data System (ADS)

    Mandelbaum, Rachel; van de Ven, Glenn; Keeton, Charles R.

    2009-09-01

    Many current and future astronomical surveys will rely on samples of strong gravitational lens systems to draw conclusions about galaxy mass distributions. We use a new strong lensing pipeline (presented in Paper I of this series) to explore selection biases that may cause the population of strong lensing systems to differ from the general galaxy population. Our focus is on point-source lensing by early-type galaxies with two mass components (stellar and dark matter) that have a variety of density profiles and shapes motivated by observational and theoretical studies of galaxy properties. We seek not only to quantify but also to understand the physics behind selection biases related to: galaxy mass, orientation and shape; dark matter profile parameters such as inner slope and concentration; and adiabatic contraction. We study how all of these properties affect the lensing Einstein radius, total cross-section, quad/double ratio and image separation distribution, with a flexible treatment of magnification bias to mimic different survey strategies. We present our results for two families of density profiles: cusped and deprojected Sérsic models. While we use fixed lens and source redshifts for most of the analysis, we show that the results are applicable to other redshift combinations, and we also explore the physics of how our results change for very different redshifts. We find significant (factors of several) selection biases with mass; orientation, for a given galaxy shape at fixed mass; cusped dark matter profile inner slope and concentration; concentration of the stellar and dark matter deprojected Sérsic models. Interestingly, the intrinsic shape of a galaxy does not strongly influence its lensing cross-section when we average over viewing angles. Our results are an important first step towards understanding how strong lens systems relate to the general galaxy population.

  15. Strongly lensed neutral hydrogen emission: detection predictions with current and future radio interferometers

    NASA Astrophysics Data System (ADS)

    Deane, R. P.; Obreschkow, D.; Heywood, I.

    2015-09-01

    Strong gravitational lensing provides some of the deepest views of the Universe, enabling studies of high-redshift galaxies only possible with next-generation facilities without the lensing phenomenon. To date, 21-cm radio emission from neutral hydrogen has only been detected directly out to z ˜ 0.2, limited by the sensitivity and instantaneous bandwidth of current radio telescopes. We discuss how current and future radio interferometers such as the Square Kilometre Array (SKA) will detect lensed H I emission in individual galaxies at high redshift. Our calculations rely on a semi-analytic galaxy simulation with realistic H I discs (by size, density profile and rotation), in a cosmological context, combined with general relativistic ray tracing. Wide-field, blind H I surveys with the SKA are predicted to be efficient at discovering lensed H I systems, increasingly so at z ≳ 2. This will be enabled by the combination of the magnification boosts, the steepness of the H I luminosity function at the high-mass end, and the fact that the H I spectral line is relatively isolated in frequency. These surveys will simultaneously provide a new technique for foreground lens selection and yield the highest redshift H I emission detections. More near term (and existing) cm-wave facilities will push the high-redshift H I envelope through targeted surveys of known lenses.

  16. Observation and Confirmation of Six Strong Lensing Systems in The Dark Energy Survey Science Verification Data

    SciTech Connect

    Nord, B.; et al.

    2015-12-09

    We report the observation and confirmation of the first group- and cluster-scale strong gravitational lensing systems found in Dark Energy Survey (DES) data. Through visual inspection of data from the Science Verification (SV) season, we identified 53 candidate systems. We then obtained spectroscopic follow-up of 21 candidates using the Gemini Multi-Object Spectrograph (GMOS) at the Gemini South telescope and the Inamori-Magellan Areal Camera and Spectrograph (IMACS) at the Magellan/Baade telescope. With this follow-up, we confirmed six candidates as gravitational lenses: Three of the systems are newly discovered, and the remaining three were previously known. Of the 21 observed candidates, the remaining 15 were either not detected in spectroscopic observations, were observed and did not exhibit continuum emission (or spectral features), or were ruled out as lensing systems. The confirmed sample consists of one group-scale and five galaxy cluster-scale lenses. The lensed sources range in redshift z ~ 0.80-3.2, and in i-band surface brightness i_{SB} ~ 23-25 mag/sq.-arcsec. (2" aperture). For each of the six systems, we estimate the Einstein radius and the enclosed mass, which have ranges ~ 5.0 - 8.6" and ~ 7.5 x 10^{12} - 6.4 x 10^{13} solar masses, respectively.

  17. The Structure of the Strongly Lensed Gamma-Ray Source B2 0218+35

    NASA Astrophysics Data System (ADS)

    Barnacka, Anna; Geller, Margaret J.; Dell’Antonio, Ian P.; Zitrin, Adi

    2016-04-01

    Strong gravitational lensing is a powerful tool for resolving the high-energy universe. We combine the temporal resolution of Fermi-LAT, the angular resolution of radio telescopes, and the independently and precisely known Hubble constant from the analysis by the Planck collaboration, to resolve the spatial origin of gamma-ray flares in the strongly lensed source B2 0218+35. The lensing model achieves 1 mas spatial resolution of the source at gamma-ray energies. The data imply that the gamma-ray flaring sites are separate from the radio core: the bright gamma-ray flare (MJD: 56160-56280) occurred 51+/- 8 pc from the 15 GHz radio core, toward the central engine. This displacement is significant at the ∼ 3σ level, and is limited primarily by the precision of the Hubble constant. B2 0218+35 is the first source where the position of the gamma-ray emitting region relative to the radio core can be resolved. We discuss the potential of an ensemble of strongly lensed high-energy sources for elucidating the physics of distant variable sources based on data from Chandra and SKA.

  18. CLASH: Joint Analysis of Strong-lensing, Weak-lensing Shear, and Magnification Data for 20 Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Umetsu, Keiichi; Zitrin, Adi; Gruen, Daniel; Merten, Julian; Donahue, Megan; Postman, Marc

    2016-04-01

    We present a comprehensive analysis of strong-lensing, weak-lensing shear and magnification data for a sample of 16 X-ray-regular and 4 high-magnification galaxy clusters at 0.19≲ z≲ 0.69 selected from Cluster Lensing And Supernova survey with Hubble (CLASH). Our analysis combines constraints from 16-band Hubble Space Telescope observations and wide-field multi-color imaging taken primarily with Suprime-Cam on the Subaru Telescope, spanning a wide range of cluster radii (10″–16‧). We reconstruct surface mass density profiles of individual clusters from a joint analysis of the full lensing constraints, and determine masses and concentrations for all of the clusters. We find the internal consistency of the ensemble mass calibration to be ≤5% ± 6% in the one-halo regime (200–2000 kpc h‑1) compared to the CLASH weak-lensing-only measurements of Umetsu et al. For the X-ray-selected subsample of 16 clusters, we examine the concentration–mass (c–M) relation and its intrinsic scatter using a Bayesian regression approach. Our model yields a mean concentration of c{| }z=0.34=3.95+/- 0.35 at M200c ≃ 14 × 1014 M⊙ and an intrinsic scatter of σ ({ln}{c}200{{c}})=0.13+/- 0.06, which is in excellent agreement with Λ cold dark matter predictions when the CLASH selection function based on X-ray morphological regularity and the projection effects are taken into account. We also derive an ensemble-averaged surface mass density profile for the X-ray-selected subsample by stacking their individual profiles. The stacked lensing signal is detected at 33σ significance over the entire radial range ≤4000 kpc h‑1, accounting for the effects of intrinsic profile variations and uncorrelated large-scale structure along the line of sight. The stacked mass profile is well described by a family of density profiles predicted for cuspy dark-matter-dominated halos in gravitational equilibrium, namely, the Navarro–Frenk–White (NFW), Einasto, and DARKexp models

  19. Strong field limit analysis of gravitational lensing in Kerr-Taub-NUT spacetime

    SciTech Connect

    Wei, Shao-Wen; Liu, Yu-Xiao; Fu, Chun-E; Yang, Ke E-mail: liuyx@lzu.edu.cn E-mail: yangke09@lzu.edu.cn

    2012-10-01

    In this paper, we study numerically the quasi-equatorial lensing by the stationary, axially-symmetric black hole in Kerr-Taub-NUT spacetime in the strong field limit. The deflection angle of light ray and other strong deflection limit coefficients are obtained numerically and they are found to be closely dependent on the NUT charge n and spin a. We also compute the magnification and the positions of the relativistic images. The caustics are studied and the results show that these caustics drift away from the optical axis, which is quite different from the Schwarzschild black hole case. Moreover, the intersections of the critical curves on the equatorial plane are obtained and it is shown that they increase with the NUT charge. These results show that there is a significant effect of the NUT charge on the strong gravitational lensing.

  20. Simple Hartmann test data interpretation for ophthalmic lenses

    NASA Astrophysics Data System (ADS)

    Salas-Peimbert, Didia Patricia; Trujillo-Schiaffino, Gerardo; González-Silva, Jorge Alberto; Almazán-Cuellar, Saúl; Malacara-Doblado, Daniel

    2006-04-01

    This article describes a simple Hartmann test data interpretation that can be used to evaluate the performance of ophthalmic lenses. Considering each spot of the Hartmann pattern such as a single test ray, using simple ray tracing analysis, it is possible to calculate the power values from the lens under test at the point corresponding with each spot. The values obtained by this procedure are used to plot the power distribution map of the entire lens. We present the results obtained applying this method with single vision, bifocal, and progressive lenses.

  1. Probing the cosmic distance duality with strong gravitational lensing and supernovae Ia data

    NASA Astrophysics Data System (ADS)

    Holanda, R. F. L.; Busti, V. C.; Alcaniz, J. S.

    2016-02-01

    We propose and perform a new test of the cosmic distance-duality relation (CDDR), DL(z) / DA(z) (1 + z)2 = 1, where DA is the angular diameter distance and DL is the luminosity distance to a given source at redshift z, using strong gravitational lensing (SGL) and type Ia Supernovae (SNe Ia) data. We show that the ratio D=DA12/DA2 and D*=DL12/DL2, where the subscripts 1 and 2 correspond, respectively, to redshifts z1 and z2, are linked by D/D*=(1+z1)2 if the CDDR is valid. We allow departures from the CDDR by defining two functions for η(z1), which equals unity when the CDDR is valid. We find that combination of SGL and SNe Ia data favours no violation of the CDDR at 1σ confidence level (η(z) simeq 1), in complete agreement with other tests and reinforcing the theoretical pillars of the CDDR.

  2. Constraints on a phiCDM model from strong gravitational lensing and updated Hubble parameter measurements

    NASA Astrophysics Data System (ADS)

    Chen, Yun; Geng, Chao-Qiang; Cao, Shuo; Huang, Yu-Mei; Zhu, Zong-Hong

    2015-02-01

    We constrain the scalar field dark energy model with an inverse power-law potential, i.e., V(phi) propto phi-α (α > 0), from a set of recent cosmological observations by compiling an updated sample of Hubble parameter measurements including 30 independent data points. Our results show that the constraining power of the updated sample of H(z) data with the HST prior on H0 is stronger than those of the SCP Union2 and Union2.1 compilations. A recent sample of strong gravitational lensing systems is also adopted to confine the model even though the results are not significant. A joint analysis of the strong gravitational lensing data with the more restrictive updated Hubble parameter measurements and the Type Ia supernovae data from SCP Union2 indicates that the recent observations still can not distinguish whether dark energy is a time-independent cosmological constant or a time-varying dynamical component.

  3. PROBING THE INNER KILOPARSEC OF MASSIVE GALAXIES WITH STRONG GRAVITATIONAL LENSING

    SciTech Connect

    Hezaveh, Yashar D.; Marshall, Philip J.; Blandford, Roger D.

    2015-01-30

    We examine the prospects of detecting demagnified images of gravitational lenses in observations of strongly lensed millimeter-wave molecular emission lines with ALMA. We model the lensing galaxies as a superposition of a dark matter component, a stellar component, and a central super-massive black hole (SMBH) and assess the detectability of the central images for a range of relevant parameters (e.g., stellar core, black hole mass, and source size). We find that over a large range of plausible parameters, future deep observations of lensed molecular lines with ALMA should enable the detection of the central images at ≳3σ significance. We use a Fisher analysis to examine the constraints that could be placed on these parameters in various scenarios and find that for large stellar cores, both the core size and the mass of the central SMBHs can be accurately measured. We also study the prospects for detecting binary SMBHs with such observations and find that only under rare conditions and with very long integrations (∼40 hr) the masses of both SMBHs may be measured using the distortions of central images.

  4. Strongly Lensed Jets, Time Delays, and the Value of H 0

    NASA Astrophysics Data System (ADS)

    Barnacka, Anna; Geller, Margaret J.; Dell'Antonio, Ian P.; Benbow, Wystan

    2015-01-01

    In principle, the most straightforward method of estimating the Hubble constant relies on time delays between mirage images of strongly lensed sources. It is a puzzle, then, that the values of H 0 obtained with this method span a range from ~50-100 km s-1Mpc-1. Quasars monitored to measure these time delays are multi-component objects. The variability may arise from different components of the quasar or may even originate from a jet. Misidentifying a variable-emitting region in a jet with emission from the core region may introduce an error in the Hubble constant derived from a time delay. Here, we investigate the complex structure of the sources as the underlying physical explanation of the wide spread in values of the Hubble constant based on gravitational lensing. Our Monte Carlo simulations demonstrate that the derived value of the Hubble constant is very sensitive to the offset between the center of the emission and the center of the variable emitting region. Therefore, we propose using the value of H 0 known from other techniques to spatially resolve the origin of the variable emission once the time delay is measured. We particularly advocate this method for gamma-ray astronomy, where the angular resolution of detectors reaches approximately 0.°1 lensed blazars offer the only route for identify the origin of gamma-ray flares. Large future samples of gravitationally lensed sources identified with Euclid, SKA, and LSST will enable a statistical determination of H 0.

  5. A Magnified Glance into the Dark Sector: Probing Cosmological Models with Strong Lensing in A1689

    NASA Astrophysics Data System (ADS)

    Magaña, Juan; Cárdenas, V. Motta ´ctor H., Vi; Verdugo, T.; Jullo, Eric

    2015-11-01

    In this paper we constrain four alternative models to the late cosmic acceleration in the universe: Chevallier–Polarski–Linder (CPL), interacting dark energy (IDE), Ricci holographic dark energy (HDE), and modified polytropic Cardassian (MPC). Strong lensing (SL) images of background galaxies produced by the galaxy cluster Abell 1689 are used to test these models. To perform this analysis we modify the LENSTOOL lens modeling code. The value added by this probe is compared with other complementary probes: Type Ia supernovae (SN Ia), baryon acoustic oscillations (BAO), and cosmic microwave background (CMB). We found that the CPL constraints obtained for the SL data are consistent with those estimated using the other probes. The IDE constraints are consistent with the complementary bounds only if large errors in the SL measurements are considered. The Ricci HDE and MPC constraints are weak, but they are similar to the BAO, SN Ia, and CMB estimations. We also compute the figure of merit as a tool to quantify the goodness of fit of the data. Our results suggest that the SL method provides statistically significant constraints on the CPL parameters but is weak for those of the other models. Finally, we show that the use of the SL measurements in galaxy clusters is a promising and powerful technique to constrain cosmological models. The advantage of this method is that cosmological parameters are estimated by modeling the SL features for each underlying cosmology. These estimations could be further improved by SL constraints coming from other galaxy clusters.

  6. Infrared Grism Confirmation of a Strongly Lensed z ~ 11 Candidate: MACS0647-JD

    NASA Astrophysics Data System (ADS)

    Coe, Dan

    2013-10-01

    The first galaxies are the frontier of extragalactic astronomy. How and when did they form, and how did they contribute to reionization? Gravitational lensing has enabled efficient discovery of high-redshift galaxies including MACS0647-JD at z ~ 10.8 (420 Myr after the Big Bang), a strong candidate for the most distant galaxy yet known. This discovery by the CLASH Multi-Cycle Treasury program is consistent with expectations extrapolated from lower redshifts (4 < z < 8). The evolving luminosity function fit to these data includes sufficient numbers of faint galaxies at early times to reionize the universe. However, the discovery of MACS0647-JD is in tension with lower number densities of z > 9 candidates identified in deep field observations including the UDF. These field studies suggest z > 9 galaxies were building up in numbers much more rapidly than observed at later times. Confirmation of the z ~ 10.8 candidate is therefore paramount to our understanding of early galaxy evolution and reionization. All three strongly lensed images of MACS0647-JD are significantly detected in two HST filters (F140W and F160W). Lower redshift objects have been ruled out with high confidence, and the redshift is corroborated by our lens modeling. The strong lensing magnification provides us with a rare opportunity to confirm such a high redshift. We propose to do so with ten orbits of WFC3/IR G141 grism observations. Two orbits of F140W imaging are also required for calibration. As the first ever HST IR grism observations of a z < 1 cluster, this program will serve as an important pathfinder for future IR grism observations of lensed fields with HST and with the James Webb Space Telescope.

  7. Dark matter fraction of low-mass cluster members probed by galaxy-scale strong lensing

    NASA Astrophysics Data System (ADS)

    Parry, W. G.; Grillo, C.; Mercurio, A.; Balestra, I.; Rosati, P.; Christensen, L.; Lombardi, M.; Caminha, G. B.; Nonino, M.; Koekemoer, A. M.; Umetsu, K.

    2016-05-01

    We present a strong lensing system, composed of four multiple images of a source at z = 2.387, created by two lens galaxies, G1 and G2, belonging to the galaxy cluster MACS J1115.9+0129 at z = 0.353. We use observations taken as part of the Cluster Lensing and Supernova survey with Hubble, and its spectroscopic follow-up programme at the Very Large Telescope, to estimate the total mass distributions of the two galaxies and the cluster through strong gravitational lensing models. We find that the total projected mass values within the half-light radii, Re, of the two lens galaxies are MT,G1(strong lensing systems will help us understand the influence that dark matter has on the structure and evolution of the inner regions of galaxies.

  8. STRONG GRAVITATIONAL LENSING BY THE SUPER-MASSIVE cD GALAXY IN ABELL 3827

    SciTech Connect

    Carrasco, E. R.; Gomez, P. L.; Lee, H.; Diaz, R.; Bergmann, M.; Turner, J. E. H.; Miller, B. W.; West, M. J.; Verdugo, T.

    2010-06-01

    We have discovered strong gravitational lensing features in the core of the nearby cluster Abell 3827 by analyzing Gemini South GMOS images. The most prominent strong lensing feature is a highly magnified, ring-shaped configuration of four images around the central cD galaxy. GMOS spectroscopic analysis puts this source at z {approx} 0.2. Located {approx}20'' away from the central galaxy is a secondary tangential arc feature which has been identified as a background galaxy with z {approx} 0.4. We have modeled the gravitational potential of the cluster core, taking into account the mass from the cluster, the brightest cluster galaxy (BCG), and other galaxies. We derive a total mass of (2.7 {+-} 0.4) x 10{sup 13} M {sub sun} within 37 h {sup -1} kpc. This mass is an order of magnitude larger than that derived from X-ray observations. The total mass derived from lensing data suggests that the BCG in this cluster is perhaps the most massive galaxy in the nearby universe.

  9. Radio and Gamma-Ray Monitoring of Strongly Lensed Quasars and Blazars

    NASA Astrophysics Data System (ADS)

    Rumbaugh, Nick; Fassnacht, Chris; McKean, John; Koopmans, Leon; Auger, Matthew; Suyu, Sherry; Marshall, Philip J.

    2015-01-01

    We observed six strongly lensed, radio-loud quasars (MG 0414+0534, CLASS B0712+472, JVAS B1030+074, CLASS B1127+385, CLASS B1152+199, and JVAS B1938+666) in order to identify systems suitable for measuring cosmological parameters using time delays between their multiple images. Two separate monitoring campaigns were carried out using the VLA. We found evidence for variability in a majority of the lightcurves. B0712 and B1030 had particularly strong variations, exhibiting linear flux trends. These results show that most of these systems should be targeted with followup monitoring campaigns, especially B0712 and B1030. In additional to these follow-up campaigns, future work will involve searching for and performing time delay measurements on lensed blazars using the Fermi gamma-ray telescope, following the proof of concept by Cheung et al. 2014. Discrepancies between gamma-ray and radio time delays of B0218 suggest physically separated emissions sources. We plan to extend study of emission regions to other lensed blazars.

  10. The mass distribution of the strong lensing cluster SDSS J1531+3414

    SciTech Connect

    Sharon, Keren; Johnson, Traci L.; Gladders, Michael D.; Rigby, Jane R.; Wuyts, Eva; Bayliss, Matthew B.; Florian, Michael K.; Dahle, Håkon

    2014-11-01

    We present the mass distribution at the core of SDSS J1531+3414, a strong-lensing cluster at z = 0.335. We find that the mass distribution is well described by two cluster-scale halos with a contribution from cluster-member galaxies. New Hubble Space Telescope observations of SDSS J1531+3414 reveal a signature of ongoing star formation associated with the two central galaxies at the core of the cluster, in the form of a chain of star forming regions at the center of the cluster. Using the lens model presented here, we place upper limits on the contribution of a possible lensed image to the flux at the central region, and rule out that this emission is coming from a background source.

  11. Kerr-Sen dilaton-axion black hole lensing in the strong deflection limit

    SciTech Connect

    Gyulchev, Galin N.; Yazadjiev, Stoytcho S.

    2007-01-15

    In the present work we study numerically quasiequatorial lensing by the charged, stationary, axially symmetric Kerr-Sen dilaton-axion black hole in the strong deflection limit. In this approximation we compute the magnification and the positions of the relativistic images. The most outstanding effect is that the Kerr-Sen black hole caustics drift away from the optical axis and shift in the clockwise direction with respect to the Kerr caustics. The intersections of the critical curves on the equatorial plane as a function of the black hole angular momentum are found, and it is shown that they decrease with the increase of the parameter Q{sup 2}/M. All of the lensing quantities are compared to particular cases as Schwarzschild, Kerr, and Gibbons-Maeda black holes.

  12. Algorithms and Programs for Strong Gravitational Lensing In Kerr Space-time Including Polarization

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Kantowski, Ronald; Dai, Xinyu; Baron, Eddie; Maddumage, Prasad

    2015-05-01

    Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python.

  13. THE CLUSTER LENSING AND SUPERNOVA SURVEY WITH HUBBLE (CLASH): STRONG-LENSING ANALYSIS OF A383 FROM 16-BAND HST/WFC3/ACS IMAGING

    SciTech Connect

    Zitrin, A.; Broadhurst, T.; Coe, D.; Postman, M.; Bradley, L.; Koekemoer, A.; Umetsu, K.; Benitez, N.; Molino, A.; Meneghetti, M.; Medezinski, E.; Zheng, W.; Ford, H.; Lemze, D.; Jouvel, S.; Lahav, O.; Merten, J.; Kelson, D.; Nonino, M.; Donahue, M.; and others

    2011-12-01

    We examine the inner mass distribution of the relaxed galaxy cluster A383 (z = 0.189), in deep 16 band Hubble Space Telescope/ACS+WFC3 imaging taken as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) multi-cycle treasury program. Our program is designed to study the dark matter distribution in 25 massive clusters, and balances depth with a wide wavelength coverage, 2000-16000 A, to better identify lensed systems and generate precise photometric redshifts. This photometric information together with the predictive strength of our strong-lensing analysis method identifies 13 new multiply lensed images and candidates, so that a total of 27 multiple images of nine systems are used to tightly constrain the inner mass profile gradient, dlog {Sigma}/dlog r {approx_equal} -0.6 {+-} 0.1 (r < 160 kpc). We find consistency with the standard distance-redshift relation for the full range spanned by the lensed images, 1.01 < z < 6.03, with the higher-redshift sources deflected through larger angles as expected. The inner mass profile derived here is consistent with the results of our independent weak-lensing analysis of wide-field Subaru images, with good agreement in the region of overlap ({approx}0.7-1 arcmin). Combining weak and strong lensing, the overall mass profile is well fitted by a Navarro-Frenk-White profile with M{sub vir} = (5.37{sup +0.70}{sub -0.63} {+-} 0.26) Multiplication-Sign 10{sup 14} M{sub Sun} h{sup -1} and a relatively high concentration, c{sub vir} = 8.77{sup +0.44}{sub -0.42} {+-} 0.23, which lies above the standard c-M relation similar to other well-studied clusters. The critical radius of A383 is modest by the standards of other lensing clusters, r{sub E} {approx_equal} 16 {+-} 2'' (for z{sub s} = 2.55), so the relatively large number of lensed images uncovered here with precise photometric redshifts validates our imaging strategy for the CLASH survey. In total we aim to provide similarly high-quality lensing data for 25 clusters

  14. Herschel Extreme Lensing Line Observations: Dynamics of Two Strongly Lensed Star-Forming Galaxies near Redshift z=2*

    NASA Technical Reports Server (NTRS)

    Rhoads, James E.; Rigby, Jane Rebecca; Malhotra, Sangeeta; Allam, Sahar; Carilli, Chris; Combes, Francoise; Finkelstein, Keely; Finkelstein, Steven; Frye, Brenda; Gerin, Maryvonne; Guillard, Pierre; Nesvadba, Nicole; Spaans, Marco; Strauss, Michael A.

    2014-01-01

    We report on two regularly rotating galaxies at redshift z approx. = 2, using high-resolution spectra of the bright [C microns] 158 micrometers emission line from the HIFI instrument on the Herschel Space Observatory. Both SDSS090122.37+181432.3 ("S0901") and SDSSJ120602.09+514229.5 ("the Clone") are strongly lensed and show the double-horned line profile that is typical of rotating gas disks. Using a parametric disk model to fit the emission line profiles, we find that S0901 has a rotation speed of v sin(i) approx. = 120 +/- 7 kms(sup -1) and a gas velocity dispersion of (standard deviation)g < 23 km s(sup -1) (1(standard deviation)). The best-fitting model for the Clone is a rotationally supported disk having v sin(i) approx. = 79 +/- 11 km s(sup -1) and (standard deviation)g 4 kms(sup -1) (1(standard deviation)). However, the Clone is also consistent with a family of dispersion-dominated models having (standard deviation)g = 92 +/- 20 km s(sup -1). Our results showcase the potential of the [C microns] line as a kinematic probe of high-redshift galaxy dynamics: [C microns] is bright, accessible to heterodyne receivers with exquisite velocity resolution, and traces dense star-forming interstellar gas. Future [C microns] line observations with ALMA would offer the further advantage of spatial resolution, allowing a clearer separation between rotation and velocity dispersion.

  15. Direct measurement of lensing amplification in Abell S1063 using a strongly lensed high redshift HII galaxy

    NASA Astrophysics Data System (ADS)

    Terlevich, Roberto; Melnick, Jorge; Terlevich, Elena; Chávez, Ricardo; Telles, Eduardo; Bresolin, Fabio; Plionis, Manolis; Basilakos, Spyros; Fernández Arenas, David; González Morán, Ana Luisa; Díaz, Ángeles I.; Aretxaga, Itziar

    2016-08-01

    ID11 is an actively star-forming, extremely compact galaxy and Lyα emitter at z = 3.117 that is gravitationally magnified by a factor of ~17 by the cluster of galaxies Hubble Frontier Fields AS1063. The observed properties of this galaxy resemble those of low luminosity HII galaxies or giant HII regions such as 30 Doradus in the Large Magellanic Cloud. Using the tight correlation correlation between the Balmer-line luminosities and the width of the emission lines (typically L(Hβ) - σ(Hβ)), which are valid for HII galaxies and giant HII regions to estimate their total luminosity, we are able to measure the lensing amplification of ID11. We obtain an amplification of 23 ± 11 that is similar within errors to the value of ~17 estimated or predicted by the best lensing models of the massive cluster Abell S1063. We also compiled, from the literature, luminosities and velocity dispersions for a set of lensed compact star-forming regions. There is more scatter in the L-σ correlation for these lensed systems, but on the whole the results tend to support the lensing model estimates of the magnification. Our result indicates that the amplification can be independently measured using the L - σ relation in lensed giant HII regions or HII galaxies. It also supports the suggestion, even if lensing is model dependent, that the L - σ relation is valid for low luminosity high-z objects. Ad hoc observations of lensed star-forming systems are required to determine the lensing amplification accurately.

  16. A redshift survey of the strong-lensing cluster ABELL 383

    SciTech Connect

    Geller, Margaret J.; Hwang, Ho Seong; Kurtz, Michael J.; Diaferio, Antonaldo; Coe, Dan; Rines, Kenneth J. E-mail: hhwang@cfa.harvard.edu E-mail: diaferio@ph.unito.it E-mail: kenneth.rines@wwu.edu

    2014-03-01

    Abell 383 is a famous rich cluster (z = 0.1887) imaged extensively as a basis for intensive strong- and weak-lensing studies. Nonetheless, there are few spectroscopic observations. We enable dynamical analyses by measuring 2360 new redshifts for galaxies with r {sub Petro} ≤ 20.5 and within 50' of the Brightest Cluster Galaxy (BCG; R.A.{sub 2000} = 42.°014125, decl.{sub 2000} = –03.°529228). We apply the caustic technique to identify 275 cluster members within 7 h {sup –1} Mpc of the hierarchical cluster center. The BCG lies within –11 ± 110 km s{sup –1} and 21 ± 56 h {sup –1} kpc of the hierarchical cluster center; the velocity dispersion profile of the BCG appears to be an extension of the velocity dispersion profile based on cluster members. The distribution of cluster members on the sky corresponds impressively with the weak-lensing contours of Okabe et al. especially when the impact of foreground and background structure is included. The values of R {sub 200} = 1.22 ± 0.01 h {sup –1} Mpc and M {sub 200} = (5.07 ± 0.09) × 10{sup 14} h {sup –1} M {sub ☉} obtained by application of the caustic technique agree well with recent completely independent lensing measures. The caustic estimate extends direct measurement of the cluster mass profile to a radius of ∼5 h {sup –1} Mpc.

  17. Strong lensing systems as a probe of dark energy in the universe

    SciTech Connect

    Biesiada, Marek

    2006-01-15

    Current advances in observational cosmology suggest that our Universe is flat and dominated by dark energy. Out of many particular models of dark energy present in the literature we focus on four: quintessence, quintessence with time varying equation of state, braneworld model and generalized Chaplygin gas model. In this paper we discuss the utility of strong lensing systems for providing additional constraints on dark energy models. In particular, we use an Einstein cross gravitational lensing system HST 14176+5226 to confront its measured characteristics with background cosmologies invoked in the context of dark energy. The image separations in the system depend on angular distances to the lens and to the source, which in turn are determined by background cosmology. This opens a possibility to constrain cosmological model provided that we have good knowledge of the lens model. We demonstrate that recent measurements of velocity dispersion in the lensing galaxy made by Subaru telescope seem to be consistent with independently obtained bounds on parameters of cosmological models considered. The method we describe is based on angular diameter distances and could become a valuable tool of cosmological model inference complementary to Hubble diagram technique based on luminosity distance.

  18. STRONGLY LENSED JETS, TIME DELAYS, AND THE VALUE OF H {sub 0}

    SciTech Connect

    Barnacka, Anna; Geller, Margaret J.; Benbow, Wystan; Dell'Antonio, Ian P.

    2015-01-20

    In principle, the most straightforward method of estimating the Hubble constant relies on time delays between mirage images of strongly lensed sources. It is a puzzle, then, that the values of H {sub 0} obtained with this method span a range from ∼50-100 km s{sup –1}Mpc{sup –1}. Quasars monitored to measure these time delays are multi-component objects. The variability may arise from different components of the quasar or may even originate from a jet. Misidentifying a variable-emitting region in a jet with emission from the core region may introduce an error in the Hubble constant derived from a time delay. Here, we investigate the complex structure of the sources as the underlying physical explanation of the wide spread in values of the Hubble constant based on gravitational lensing. Our Monte Carlo simulations demonstrate that the derived value of the Hubble constant is very sensitive to the offset between the center of the emission and the center of the variable emitting region. Therefore, we propose using the value of H {sub 0} known from other techniques to spatially resolve the origin of the variable emission once the time delay is measured. We particularly advocate this method for gamma-ray astronomy, where the angular resolution of detectors reaches approximately 0.°1; lensed blazars offer the only route for identify the origin of gamma-ray flares. Large future samples of gravitationally lensed sources identified with Euclid, SKA, and LSST will enable a statistical determination of H {sub 0}.

  19. ALMA OBSERVATIONS OF SPT-DISCOVERED, STRONGLY LENSED, DUSTY, STAR-FORMING GALAXIES

    SciTech Connect

    Hezaveh, Y. D.; Marrone, D. P.; Spilker, J. S.; Bothwell, M.; Fassnacht, C. D.; Vieira, J. D.; Aguirre, J. E.; Aird, K. A.; Aravena, M.; De Breuck, C.; Ashby, M. L. N.; Bayliss, M.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T.; Brodwin, M.; Chapman, S. C.; and others

    2013-04-20

    We present Atacama Large Millimeter/submillimeter Array (ALMA) 860 {mu}m imaging of four high-redshift (z = 2.8-5.7) dusty sources that were detected using the South Pole Telescope (SPT) at 1.4 mm and are not seen in existing radio to far-infrared catalogs. At 1.''5 resolution, the ALMA data reveal multiple images of each submillimeter source, separated by 1''-3'', consistent with strong lensing by intervening galaxies visible in near-IR imaging of these sources. We describe a gravitational lens modeling procedure that operates on the measured visibilities and incorporates self-calibration-like antenna phase corrections as part of the model optimization, which we use to interpret the source structure. Lens models indicate that SPT0346-52, located at z = 5.7, is one of the most luminous and intensely star-forming sources in the universe with a lensing corrected FIR luminosity of 3.7 Multiplication-Sign 10{sup 13} L{sub Sun} and star formation surface density of 4200 M{sub Sun} yr{sup -1} kpc{sup -2}. We find magnification factors of 5 to 22, with lens Einstein radii of 1.''1-2.''0 and Einstein enclosed masses of 1.6-7.2 Multiplication-Sign 10{sup 11} M{sub Sun }. These observations confirm the lensing origin of these objects, allow us to measure their intrinsic sizes and luminosities, and demonstrate the important role that ALMA will play in the interpretation of lensed submillimeter sources.

  20. Discovery of A Very Bright, Strongly-Lensed z=2 Galaxy in the SDSS DR5

    SciTech Connect

    Lin, Huan; Buckley-Geer, Elizabeth; Allam, Sahar S.; Tucker, Douglas L.; Diehl, H.Thomas; Kubik, Donna; Kubo, Jeffrey M.; Annis, James; Frieman, Joshua A.; Oguri, Masamune; Inada, Naohisa; /Wako, RIKEN

    2008-09-30

    We report on the discovery of a very bright z = 2.00 star-forming galaxy that is strongly lensed by a foreground z = 0.422 luminous red galaxy (LRG). This system was found in a systematic search for bright arcs lensed by LRGs and brightest cluster galaxies in the Sloan Digital Sky Survey Data Release 5 sample. Follow-up observations on the Subaru 8.2m telescope on Mauna Kea and the Astrophysical Research Consortium 3.5m telescope at Apache Point Observatory confirmed the lensing nature of this system. A simple lens model for the system, assuming a singular isothermal ellipsoid mass distribution, yields an Einstein radius of {theta}{sub Ein} = 3.82 {+-} 0.03{double_prime} or 14.8 {+-} 0.1h{sup -1} kpc at the lens redshift. The total projected mass enclosed within the Einstein radius is 2.10 {+-} 0.03 x 10{sup 12}h{sup -1}M{sub {circle_dot}}, and the magnification factor for the source galaxy is 27 {+-} 1. Combining the lens model with our gVriz photometry, we find an (unlensed) star formation rate for the source galaxy of 32 h{sup -1} M{sub {circle_dot}} hr{sup -1}, adopting a fiducial constant star formation rate model with an age of 100 Myr and E(B-V) = 0.25. With an apparent magnitude of r = 19.9, this system is among the very brightest lensed z {ge} 2 galaxies, and provides an excellent opportunity to pursue detailed studies of the physical properties of an individual high-redshift star-forming galaxy.

  1. DISCOVERY OF A VERY BRIGHT, STRONGLY LENSED z = 2 GALAXY IN THE SDSS DR5

    SciTech Connect

    Lin Huan; Buckley-Geer, Elizabeth; Allam, Sahar S.; Tucker, Douglas L.; Diehl, H. Thomas; Kubik, Donna; Kubo, Jeffrey M.; Annis, James; Frieman, Joshua A.; Oguri, Masamune; Inada, Naohisa

    2009-07-10

    We report on the discovery of a very bright z = 2.00 star-forming galaxy that is strongly lensed by a foreground z = 0.422 luminous red galaxy (LRG), SDSS J120602.09+514229.5. This system, nicknamed the 'Clone', was found in a systematic search for bright arcs lensed by LRGs and brightest cluster galaxies in the Sloan Digital Sky Survey Data Release 5 sample. Follow-up observations on the Subaru 8.2 m telescope on Mauna Kea and the Astrophysical Research Consortium 3.5 m telescope at Apache Point Observatory confirmed the lensing nature of this system. A simple lens model for the system, assuming a singular isothermal ellipsoid mass distribution, yields an Einstein radius of {theta}{sub Ein} = 3.82 {+-} 0.''03 or 14.8 {+-} 0.1 h{sup -1} kpc at the lens redshift. The total projected mass enclosed within the Einstein radius is 2.10 {+-} 0.03 x 10{sup 12} h {sup -1} M{sub sun}, and the magnification factor for the source galaxy is 27 {+-} 1. Combining the lens model with our gVriz photometry, we find a (unlensed) star formation rate (SFR) for the source galaxy of 32 h{sup -1} M {sub sun} yr{sup -1}, adopting a fiducial constant SFR model with an age of 100 Myr and E(B - V) = 0.25. With an apparent magnitude of r = 19.8, this system is among the very brightest lensed z {>=} 2 galaxies, and provides an excellent opportunity to pursue detailed studies of the physical properties of an individual high-redshift star-forming galaxy.

  2. Herschel extreme lensing line observations: Dynamics of two strongly lensed star-forming galaxies near redshift z = 2

    SciTech Connect

    Rhoads, James E.; Malhotra, Sangeeta; Allam, Sahar; Carilli, Chris; Combes, Françoise; Finkelstein, Keely; Finkelstein, Steven; Frye, Brenda; Gerin, Maryvonne; Guillard, Pierre; Nesvadba, Nicole; Rigby, Jane; Spaans, Marco; Strauss, Michael A.

    2014-05-20

    We report on two regularly rotating galaxies at redshift z ≈ 2, using high-resolution spectra of the bright [C II] 158 μm emission line from the HIFI instrument on the Herschel Space Observatory. Both SDSS090122.37+181432.3 ({sup S}0901{sup )} and SDSSJ120602.09+514229.5 ({sup t}he Clone{sup )} are strongly lensed and show the double-horned line profile that is typical of rotating gas disks. Using a parametric disk model to fit the emission line profiles, we find that S0901 has a rotation speed of vsin (i) ≈ 120 ± 7 km s{sup –1} and a gas velocity dispersion of σ {sub g} < 23 km s{sup –1} (1σ). The best-fitting model for the Clone is a rotationally supported disk having vsin (i) ≈ 79 ± 11 km s{sup –1} and σ {sub g} ≲ 4 km s{sup –1} (1σ). However, the Clone is also consistent with a family of dispersion-dominated models having σ {sub g} = 92 ± 20 km s{sup –1}. Our results showcase the potential of the [C II] line as a kinematic probe of high-redshift galaxy dynamics: [C II] is bright, accessible to heterodyne receivers with exquisite velocity resolution, and traces dense star-forming interstellar gas. Future [C II] line observations with ALMA would offer the further advantage of spatial resolution, allowing a clearer separation between rotation and velocity dispersion.

  3. The Third Gravitational Lensing Accuracy Testing (GREAT3) Challenge Handbook

    NASA Astrophysics Data System (ADS)

    Mandelbaum, Rachel; Rowe, Barnaby; Bosch, James; Chang, Chihway; Courbin, Frederic; Gill, Mandeep; Jarvis, Mike; Kannawadi, Arun; Kacprzak, Tomasz; Lackner, Claire; Leauthaud, Alexie; Miyatake, Hironao; Nakajima, Reiko; Rhodes, Jason; Simet, Melanie; Zuntz, Joe; Armstrong, Bob; Bridle, Sarah; Coupon, Jean; Dietrich, Jörg P.; Gentile, Marc; Heymans, Catherine; Jurling, Alden S.; Kent, Stephen M.; Kirkby, David; Margala, Daniel; Massey, Richard; Melchior, Peter; Peterson, John; Roodman, Aaron; Schrabback, Tim

    2014-05-01

    The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is the third in a series of image analysis challenges, with a goal of testing and facilitating the development of methods for analyzing astronomical images that will be used to measure weak gravitational lensing. This measurement requires extremely precise estimation of very small galaxy shape distortions, in the presence of far larger intrinsic galaxy shapes and distortions due to the blurring kernel caused by the atmosphere, telescope optics, and instrumental effects. The GREAT3 challenge is posed to the astronomy, machine learning, and statistics communities, and includes tests of three specific effects that are of immediate relevance to upcoming weak lensing surveys, two of which have never been tested in a community challenge before. These effects include many novel aspects including realistically complex galaxy models based on high-resolution imaging from space; a spatially varying, physically motivated blurring kernel; and a combination of multiple different exposures. To facilitate entry by people new to the field, and for use as a diagnostic tool, the simulation software for the challenge is publicly available, though the exact parameters used for the challenge are blinded. Sample scripts to analyze the challenge data using existing methods will also be provided. See http://great3challenge.info and http://great3.projects.phys.ucl.ac.uk/leaderboard/ for more information.

  4. Optical performance test & analysis of intraocular lenses

    NASA Astrophysics Data System (ADS)

    Choi, Junoh

    Cataract is a condition in the eye that if left untreated, could lead to blindness. One of the effective ways to treat cataract is the removal of the cataractous natural crystalline lens and implantation of an artificial lens called an intraocular lens(IOL). The designs of the IOLs have shown improvements over the years to further imitate natural human vision. A need for an objective testing and analysis tool for the latest IOLs grow with the advancements of the IOLs. In this dissertation, I present a system capable of objective test and analysis of the advanced IOLs. The system consists of (1) Model eye into which an IOL can be inserted to mimic conditions of the human eye. (2) Modulation Transfer Function measurement setup capable of through-focus test for depth of field studies and polychromatic test for study of effects of chromatization. (3) Use of Defocus Transfer Function to simulate depth of field characteristic of rotationally symmetric multifocal designs and extension of the function to polychromatic conditions. (4) Several target imaging experiments for comparison of stray light artifacts and simulation using a non-sequential ray trace package.

  5. INCLINATION-DEPENDENT ACTIVE GALACTIC NUCLEUS FLUX PROFILES FROM STRONG LENSING OF THE KERR SPACETIME

    SciTech Connect

    Chen, Bin; Dai, Xinyu; Baron, E.

    2013-01-10

    Recent quasar microlensing observations have constrained the X-ray emission sizes of quasars to be about 10 gravitational radii, one order of magnitude smaller than the optical emission sizes. Using a new ray-tracing code for the Kerr spacetime, we find that the observed X-ray flux is strongly influenced by the gravity field of the central black hole, even for observers at moderate inclination angles. We calculate inclination-dependent flux profiles of active galactic nuclei in the optical and X-ray bands by combining the Kerr lensing and projection effects for future reference. We further study the dependence of the X-ray-to-optical flux ratio on the inclination angle caused by differential lensing distortion of the X-ray and optical emission, assuming several corona geometries. The strong lensing X-ray-to-optical magnification ratio can change by a factor of {approx}10 for normal quasars in some cases, and a further factor of {approx}10 for broad absorption line (BAL) quasars and obscured quasars. Comparing our results with the observed distributions in normal and BAL quasars, we find that the inclination angle dependence of the magnification ratios can significantly change the X-ray-to-optical flux ratio distributions. In particular, the mean value of the spectrum slope parameter {alpha}{sub ox}, 0.3838log F {sub 2keV}/F {sub 2500A}, can differ by {approx}0.1-0.2 between normal and BAL quasars, depending on corona geometries, suggesting larger intrinsic absorptions in BAL quasars.

  6. Constraints on the identity of the dark matter from strong gravitational lenses

    NASA Astrophysics Data System (ADS)

    Li, Ran; Frenk, Carlos S.; Cole, Shaun; Gao, Liang; Bose, Sownak; Hellwing, Wojciech A.

    2016-07-01

    The cold dark matter (CDM) cosmological model unambiguously predicts that a large number of haloes should survive as subhaloes when they are accreted into a larger halo. The CDM model would be ruled out if such substructures were shown not to exist. By contrast, if the dark matter consists of Warm Dark Matter (WDM) particles, then below a threshold mass that depends on the particle mass far fewer substructures would be present. Finding subhaloes below a certain mass would then rule out warm particle masses below some value. Strong gravitational lensing provides a clean method to measure the subhalo mass function through distortions in the structure of Einstein rings and giant arcs. Using mock lensing observations constructed from high-resolution N-body simulations, we show that measurements of approximately 100 strong lens systems with a detection limit of Mlow = 107 h-1 M⊙ would clearly distinguish CDM from WDM in the case where this consists of 7 keV sterile neutrinos such as those that might be responsible for the 3.5 keV X-ray emission line recently detected in galaxies and clusters.

  7. Constraints on the identity of the dark matter from strong gravitational lenses

    NASA Astrophysics Data System (ADS)

    Li, Ran; Frenk, Carlos S.; Cole, Shaun; Gao, Liang; Bose, Sownak; Hellwing, Wojciech A.

    2016-07-01

    The cold dark matter (CDM) cosmological model unambigously predicts that a large number of haloes should survive as subhaloes when they are accreted into a larger halo. The CDM model would be ruled out if such substructures were shown not to exist. By contrast, if the dark matter consists of warm particles (WDM), then below a threshold mass that depends on the particle mass far fewer substructures would be present. Finding subhaloes below a certain mass would then rule out warm particle masses below some value. Strong gravitational lensing provides a clean method to measure the subhalo mass function through distortions in the structure of Einstein rings and giant arcs.Using mock lensing observations constructed from high-resolution N-body simulations, we show that measurements of approximately 100 strong lens systems with a detection limit of $10^7 h^{-1} M_{\\odot}$ would clearly distinguish CDM from WDM in the case where this consists of 7 keV sterile neutrinos such as those that might be responsible for the 3.5 keV X-ray emission line recently detected in galaxies and clusters.

  8. Constraints on the identity of the dark matter from strong gravitational lenses

    NASA Astrophysics Data System (ADS)

    Li, Ran; Frenk, Carlos S.; Cole, Shaun; Gao, Liang; Bose, Sownak; Hellwing, Wojciech A.

    2016-04-01

    The Cold Dark Matter (CDM) cosmological model unambigously predicts that a large number of haloes should survive as subhaloes when they are accreted into a larger halo. The CDM model would be ruled out if such substructures were shown not to exist. By contrast, if the dark matter consists of Warm Dark Matter particles (WDM), then below a threshold mass that depends on the particle mass far fewer substructures would be present. Finding subhaloes below a certain mass would then rule out warm particle masses below some value. Strong gravitational lensing provides a clean method to measure the subhalo mass function through distortions in the structure of Einstein rings and giant arcs. Using mock lensing observations constructed from high-resolution N-body simulations, we show that measurements of approximately 100 strong lens systems with a detection limit of Mlow = 107h-1M⊙ would clearly distinguish CDM from WDM in the case where this consists of 7 keV sterile neutrinos such as those that might be responsible for the 3.5 keV X-ray emission line recently detected in galaxies and clusters.

  9. Constraints on a φCDM model from strong gravitational lensing and updated Hubble parameter measurements

    SciTech Connect

    Chen, Yun; Geng, Chao-Qiang; Cao, Shuo; Huang, Yu-Mei; Zhu, Zong-Hong E-mail: geng@phys.nthu.edu.tw E-mail: huangymei@gmail.com

    2015-02-01

    We constrain the scalar field dark energy model with an inverse power-law potential, i.e., V(φ) ∝ φ{sup −α} (α > 0), from a set of recent cosmological observations by compiling an updated sample of Hubble parameter measurements including 30 independent data points. Our results show that the constraining power of the updated sample of H(z) data with the HST prior on H{sub 0} is stronger than those of the SCP Union2 and Union2.1 compilations. A recent sample of strong gravitational lensing systems is also adopted to confine the model even though the results are not significant. A joint analysis of the strong gravitational lensing data with the more restrictive updated Hubble parameter measurements and the Type Ia supernovae data from SCP Union2 indicates that the recent observations still can not distinguish whether dark energy is a time-independent cosmological constant or a time-varying dynamical component.

  10. Systematic or signal? How dark matter misalignments can bias strong lensing models of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Harvey, D.; Kneib, J. P.; Jauzac, M.

    2016-05-01

    We explore how assuming that mass traces light in strong gravitational lensing models can lead to systematic errors in the predicted position of multiple images. Using a model based on the galaxy cluster MACS J0416 (z = 0.397) from the Hubble Frontier Fields, we split each galactic halo into a baryonic and dark matter component. We then shift the dark matter halo such that it no longer aligns with the baryonic halo and investigate how this affects the resulting position of multiple images. We find for physically motivated misalignments in dark halo position, ellipticity, position angle and density profile that multiple images can move on average by more than 0.2 arcsec with individual images moving greater than 1 arcsec. We finally estimate the full error induced by assuming that light traces mass and find that this assumption leads to an expected rms error of 0.5 arcsec, almost the entire error budget observed in the Frontier Fields. Given the large potential contribution from the assumption that light traces mass to the error budget in mass reconstructions, we predict that it should be possible to make a first significant detection and characterization of dark halo misalignments in the Hubble Frontier Fields with strong lensing. Finally, we find that it may be possible to detect ˜1 kpc offsets between dark matter and baryons, the smoking gun for self-interacting dark matter, should the correct alignment of multiple images be observed.

  11. COSMOS 5921+0638: characterization and analysis of a new strong gravitationally lensed AGN

    NASA Astrophysics Data System (ADS)

    Anguita, T.; Faure, C.; Kneib, J.-P.; Wambsganss, J.; Knobel, C.; Koekemoer, A. M.; Limousin, M.

    2009-11-01

    Context: Strong lens candidates have been newly identified within the COSMOS field. We present VLT/FORS1 spectroscopic follow-up observations and HST/WFPC2 imaging of the system COSMOS 5921+0638, which exhibits quadruply lensed images and a perfect Einstein ring. Aims: We investigate the nature of COSMOS 5921+0638 by studying its photometric, spectroscopic and physical properties. Methods: By analyzing our VLT/FORS1 spectroscopy and Subaru/CFHT/HST imaging of COSMOS 5921+0638, we completed both an environmental analysis and detailed analytical and grid-based mass modeling to determine it properties. Results: We measured the redshifts of the lensing galaxy in COSMOS 5921+0638 (zl = 0.551 ± 0.001) and 9 additional galaxies in the field (5 of them at z ~ 0.35). The redshift of the lensed source was inferred by identifying a candidate Lyα line at zs = 3.14 ± 0.05. The mass modeling reveals the requirement of a small external shear (γ = 0.038), which is slightly larger than the lensing contribution expected by galaxy groups along the line-of-sight obtained from the zCOSMOS optical group catalog (κ_groups ~ 0.01 and γ_groups ~ 0.005). The estimated time-delays between the different images are of the order of hours to half a week and the total magnification of the background source is μ ≈ 150. The measured mass-to-light ratio of the lensing galaxy within the Einstein ring is M/LB ≈ 8.5 ± 1.6. Anomalies are observed between the measured and expected flux ratios of the images of the background AGN. Conclusions: Our analysis indicates that the ring and point-like structures in COSMOS 5921+0638 consist of a lensed high redshift galaxy hosting a low luminosity AGN (LLAGN). The observed flux ratio anomalies are probably due to microlensing by stars in the lensing galaxy and/or a combination of static phenomena. Multi-epoch, multi-band space-based observations would allow us to differentiate between the possible causes of these anomalies, since static and/or dynamic

  12. TESTING THE DARK ENERGY WITH GRAVITATIONAL LENSING STATISTICS

    SciTech Connect

    Cao Shuo; Zhu Zonghong; Covone, Giovanni

    2012-08-10

    We study the redshift distribution of two samples of early-type gravitational lenses, extracted from a larger collection of 122 systems, to constrain the cosmological constant in the {Lambda}CDM model and the parameters of a set of alternative dark energy models (XCDM, Dvali-Gabadadze-Porrati, and Ricci dark energy models), in a spatially flat universe. The likelihood is maximized for {Omega}{sub {Lambda}} = 0.70 {+-} 0.09 when considering the sample excluding the Sloan Lens ACS systems (known to be biased toward large image-separation lenses) and no-evolution, and {Omega}{sub {Lambda}} = 0.81 {+-} 0.05 when limiting to gravitational lenses with image separation {Delta}{theta} > 2'' and no-evolution. In both cases, results accounting for galaxy evolution are consistent within 1{sigma}. The present test supports the accelerated expansion, by excluding the null hypothesis (i.e., {Omega}{sub {Lambda}} = 0) at more than 4{sigma}, regardless of the chosen sample and assumptions on the galaxy evolution. A comparison between competitive world models is performed by means of the Bayesian information criterion. This shows that the simplest cosmological constant model-that has only one free parameter-is still preferred by the available data on the redshift distribution of gravitational lenses. We perform an analysis of the possible systematic effects, finding that the systematic errors due to sample incompleteness, galaxy evolution, and model uncertainties approximately equal the statistical errors, with present-day data. We find that the largest sources of systemic errors are the dynamical normalization and the high-velocity cutoff factor, followed by the faint-end slope of the velocity dispersion function.

  13. Strong lensing probability in TeVeS (tensor-vector-scalar) theory

    SciTech Connect

    Chen Daming

    2008-01-15

    We recalculate the strong lensing probability as a function of the image separation in TeVeS (tensor-vector-scalar) cosmology, which is a relativistic version of MOND (MOdified Newtonian Dynamics). The lens is modeled by the Hernquist profile. We assume an open cosmology with {Omega}{sub b} = 0.04 and {Omega}{sub {Lambda}} = 0.5 and three different kinds of interpolating functions. Two different galaxy stellar mass functions (GSMF) are adopted: PHJ (Panter, Heavens and Jimenez 2004 Mon. Not. R. Astron. Soc. 355 764) determined from SDSS data release 1 and Fontana (Fontana et al 2006 Astron. Astrophys. 459 745) from GOODS-MUSIC catalog. We compare our results with both the predicted probabilities for lenses from singular isothermal sphere galaxy halos in LCDM (Lambda cold dark matter) with a Schechter-fit velocity function, and the observational results for the well defined combined sample of the Cosmic Lens All-Sky Survey (CLASS) and Jodrell Bank/Very Large Array Astrometric Survey (JVAS). It turns out that the interpolating function {mu}(x) = x/(1+x) combined with Fontana GSMF matches the results from CLASS/JVAS quite well.

  14. Strong gravitational lensing as a tool to investigate the structure of jets at high energies

    SciTech Connect

    Barnacka, Anna; Geller, Margaret J.; Benbow, Wystan; Dell'antonio, Ian P.

    2014-06-20

    The components of blazar jets that emit radiation span a factor of 10{sup 10} in scale. The spatial structure of these emitting regions depends on the observed energy. Photons emitted at different sites cross the lens plane at different distances from the mass-weighted center of the lens. Thus there are differences in magnification ratios and time delays between the images of lensed blazars observed at different energies. When the lens structure and redshift are known from optical observations, these constraints can elucidate the structure of the source at high energies. At these energies, current technology is inadequate to resolve these sources, and the observed light curve is thus the sum of the images. Durations of γ-ray flares are short compared with typical time delays; thus both the magnification ratio and the time delay can be measured for the delayed counterparts. These measurements are a basis for localizing the emitting region along the jet. To demonstrate the power of strong gravitational lensing, we build a toy model based on the best studied and the nearest relativistic jet M87.

  15. CENTRAL DARK MATTER TRENDS IN EARLY-TYPE GALAXIES FROM STRONG LENSING, DYNAMICS, AND STELLAR POPULATIONS

    SciTech Connect

    Tortora, C.; Jetzer, P.; Napolitano, N. R.; Romanowsky, A. J.

    2010-09-20

    We analyze the correlations between central dark matter (DM) content of early-type galaxies and their sizes and ages, using a sample of intermediate-redshift (z {approx} 0.2) gravitational lenses from the SLACS survey, and by comparing them to a larger sample of z {approx} 0 galaxies. We decompose the deprojected galaxy masses into DM and stellar components using combinations of strong lensing, stellar dynamics, and stellar populations modeling. For a given stellar mass, we find that for galaxies with larger sizes, the DM fraction increases and the mean DM density decreases, consistently with the cuspy halos expected in cosmological formation scenarios. The DM fraction also decreases with stellar age, which can be partially explained by the inverse correlation between size and age. The residual trend may point to systematic dependencies on formation epoch of halo contraction or stellar initial mass functions. These results are in agreement with recent findings based on local galaxies by Napolitano et al. and suggest negligible evidence of galaxy evolution over the last {approx}2.5 Gyr other than passive stellar aging.

  16. High power tungstate-crystal Raman laser operating in the strong thermal lensing regime.

    PubMed

    McKay, Aaron; Kitzler, Ondrej; Mildren, Richard P

    2014-01-13

    We report an investigation into a double metal tungstate Raman laser when pumped at elevated average powers. Potassium gadolinium tungstate (KGW) was placed in an external cavity configured for second-Stokes output and pumped at pulse repetition rate of 38 kHz with up to 46 W of average power. For output powers above 3 W, we observe preferential excitation of Hermite-Gaussian transverse modes whose order in the X(1)(') principal direction of the thermal expansion tensor scales linearly with Raman power. We deduce that strong astigmatic thermal lensing is induced in the Raman crystal with a negative component in the X(1)(') direction. At maximum pump power, 8.3 W of output power was obtained at a conversion efficiency of 18%. PMID:24515030

  17. Strong bimodality in the host halo mass of central galaxies from galaxy-galaxy lensing

    NASA Astrophysics Data System (ADS)

    Mandelbaum, Rachel; Wang, Wenting; Zu, Ying; White, Simon; Henriques, Bruno; More, Surhud

    2016-04-01

    We use galaxy-galaxy lensing to study the dark matter haloes surrounding a sample of locally brightest galaxies (LBGs) selected from the Sloan Digital Sky Survey. We measure mean halo mass as a function of the stellar mass and colour of the central galaxy. Mock catalogues constructed from semi-analytic galaxy formation simulations demonstrate that most LBGs are the central objects of their haloes, greatly reducing interpretation uncertainties due to satellite contributions to the lensing signal. Over the full stellar mass range, 10.3 < log [M*/M⊙] < 11.6, we find that passive central galaxies have haloes that are at least twice as massive as those of star-forming objects of the same stellar mass. The significance of this effect exceeds 3σ for log [M*/M⊙] > 10.7. Tests using the mock catalogues and on the data themselves clarify the effects of LBG selection and show that it cannot artificially induce a systematic dependence of halo mass on LBG colour. The bimodality in halo mass at fixed stellar mass is reproduced by the astrophysical model underlying our mock catalogue, but the sign of the effect is inconsistent with recent, nearly parameter-free age-matching models. The sign and magnitude of the effect can, however, be reproduced by halo occupation distribution models with a simple (few-parameter) prescription for type dependence.

  18. TWO ACCURATE TIME-DELAY DISTANCES FROM STRONG LENSING: IMPLICATIONS FOR COSMOLOGY

    SciTech Connect

    Suyu, S. H.; Treu, T.; Auger, M. W.; Hilbert, S.; Blandford, R. D.; Marshall, P. J.; Tewes, M.; Courbin, F.; Meylan, G.; Fassnacht, C. D.; Koopmans, L. V. E.; Sluse, D.

    2013-04-01

    Strong gravitational lenses with measured time delays between the multiple images and models of the lens mass distribution allow a one-step determination of the time-delay distance, and thus a measure of cosmological parameters. We present a blind analysis of the gravitational lens RXJ1131-1231 incorporating (1) the newly measured time delays from COSMOGRAIL, the COSmological MOnitoring of GRAvItational Lenses, (2) archival Hubble Space Telescope imaging of the lens system, (3) a new velocity-dispersion measurement of the lens galaxy of 323 {+-} 20 km s{sup -1} based on Keck spectroscopy, and (4) a characterization of the line-of-sight structures via observations of the lens' environment and ray tracing through the Millennium Simulation. Our blind analysis is designed to prevent experimenter bias. The joint analysis of the data sets allows a time-delay distance measurement to 6% precision that takes into account all known systematic uncertainties. In combination with the Wilkinson Microwave Anisotropy Probe seven-year (WMAP7) data set in flat wCDM cosmology, our unblinded cosmological constraints for RXJ1131-1231 are H{sub 0}=80.0{sup +5.8}{sub -5.7} km s{sup -1} Mpc{sup -1}, {Omega}{sub de} = 0.79 {+-} 0.03, and w=-1.25{sup +0.17}{sub -0.21}. We find the results to be statistically consistent with those from the analysis of the gravitational lens B1608+656, permitting us to combine the inferences from these two lenses. The joint constraints from the two lenses and WMAP7 are H{sub 0}=75.2{sup +4.4}{sub -4.2} km s{sup -1} Mpc{sup -1}, {Omega}{sub de}=0.76{sup +0.02}{sub -0.03}, and w = -1.14{sup +0.17}{sub -0.20} in flat wCDM, and H{sub 0}=73.1{sup +2.4}{sub -3.6} km s{sup -1} Mpc{sup -1}, {Omega}{sub {Lambda}}=0.75{sup +0.01}{sub -0.02}, and {Omega}{sub k}=0.003{sup +0.005}{sub -0.006} in open {Lambda}CDM. Time-delay lenses constrain especially tightly the Hubble constant H{sub 0} (5.7% and 4.0% respectively in wCDM and open {Lambda}CDM) and curvature of the

  19. The Gini Coefficient as a Tool for Image Family Idenitification in Strong Lensing Systems with Multiple Images

    NASA Astrophysics Data System (ADS)

    Florian, Michael K.; Gladders, Michael D.; Li, Nan; Sharon, Keren

    2016-01-01

    The sample of cosmological strong lensing systems has been steadily growing in recent years and with the advent of the next generation of space-based survey telescopes, the sample will reach into the thousands. The accuracy of strong lens models relies on robust identification of multiple image families of lensed galaxies. For the most massive lenses, often more than one background galaxy is magnified and multiply imaged, and even in the cases of only a single lensed source, identification of counter images is not always robust. Recently, we have shown that the Gini coefficient in space-telescope-quality imaging is a measurement of galaxy morphology that is relatively well-preserved by strong gravitational lensing. Here, we investigate its usefulness as a diagnostic for the purposes of image family identification and show that it can remove some of the degeneracies encountered when using color as the sole diagnostic, and can do so without the need for additional observations since whenever a color is available, two Gini coefficients are as well.

  20. CLASH: THREE STRONGLY LENSED IMAGES OF A CANDIDATE z Almost-Equal-To 11 GALAXY

    SciTech Connect

    Coe, Dan; Postman, Marc; Bradley, Larry; Koekemoer, Anton; Zitrin, Adi; Carrasco, Mauricio; Shu, Xinwen; Zheng, Wei; Ford, Holland; Rodney, Steven A.; Bouwens, Rychard; Broadhurst, Tom; Host, Ole; Jouvel, Stephanie; Moustakas, Leonidas A.; Moustakas, John; Van der Wel, Arjen; Donahue, Megan; Benitez, Narciso; and others

    2013-01-01

    We present a candidate for the most distant galaxy known to date with a photometric redshift of z = 10.7{sup +0.6} {sub -0.4} (95% confidence limits; with z < 9.5 galaxies of known types ruled out at 7.2{sigma}). This J-dropout Lyman break galaxy, named MACS0647-JD, was discovered as part of the Cluster Lensing and Supernova survey with Hubble (CLASH). We observe three magnified images of this galaxy due to strong gravitational lensing by the galaxy cluster MACSJ0647.7+7015 at z = 0.591. The images are magnified by factors of {approx}80, 7, and 2, with the brighter two observed at {approx}26th magnitude AB ({approx}0.15 {mu}Jy) in the WFC3/IR F160W filter ({approx}1.4-1.7 {mu}m) where they are detected at {approx}>12{sigma}. All three images are also confidently detected at {approx}>6{sigma} in F140W ({approx}1.2-1.6 {mu}m), dropping out of detection from 15 lower wavelength Hubble Space Telescope filters ({approx}0.2-1.4 {mu}m), and lacking bright detections in Spitzer/IRAC 3.6 {mu}m and 4.5 {mu}m imaging ({approx}3.2-5.0 {mu}m). We rule out a broad range of possible lower redshift interlopers, including some previously published as high-redshift candidates. Our high-redshift conclusion is more conservative than if we had neglected a Bayesian photometric redshift prior. Given CLASH observations of 17 high-mass clusters to date, our discoveries of MACS0647-JD at z {approx} 10.8 and MACS1149-JD at z {approx} 9.6 are consistent with a lensed luminosity function extrapolated from lower redshifts. This would suggest that low-luminosity galaxies could have reionized the universe. However, given the significant uncertainties based on only two galaxies, we cannot yet rule out the sharp drop-off in number counts at z {approx}> 10 suggested by field searches.

  1. Search for strong gravitational lensing effect in the current GRB data of BATSE

    NASA Astrophysics Data System (ADS)

    Li, ChunYu; Li, LiXin

    2014-08-01

    Because gamma-ray bursts (GRBs) trace the high- z universe, there is an appreciable probability for a GRB to be gravitational lensed by galaxies in the universe. Herein we consider the gravitational lensing effect of GRBs contributed by the dark matter halos in galaxies. Assuming that all halos have the singular isothermal sphere (SIS) mass profile in the mass range 1010 h -1 M ⊙ < M < 2×1013 h -1 M ⊙ and all GRB samples follow the intrinsic redshift distribution and luminosity function derived from the Swift LGRBs sample, we calculated the gravitational lensing probability in BATSE, Swift/BAT and Fermi/GBM GRBs, respectively. With an derived probability result in BATSE GRBs, we searched for lensed GRB pairs in the BATSE5B GRB Spectral catalog. The search did not find any convincing gravitationally lensed events. We discuss our result and future observations for GRB lensing observation.

  2. Search and Analysis of Galaxy-Scale Strong Gravitational Lenses in Cosmological Surveys

    NASA Astrophysics Data System (ADS)

    Brault, F.

    2013-11-01

    This article focuses on the development of a novel detector of strong galaxy-galaxy lenses based on the massive modelling of candidates in wide-field ground-based imaging data. Indeed, not only are these events rare in the Universe, but they are at the same time very valuable to understand galaxy formation and evolution in a cosmological context. We use parametric models, which are optimized by MCMC in a bayesian framework, so that we know the distribution of errors. We first generate several training samples : a hundred lenses simulated in HST and CFHT conditions, along with 325 observed lens candidates resulting from a series of preselections on the CFHTLS-Wide galaxies, and that we classify according to their credibility. The whole challenge in designing this detector lies in a subtle balance between the quality of models and the execution time. We massively run the modelling on our samples, beginning with ideal application conditions that we make more complex by stages so as to get closer to the observation conditions and save time. We show that a 7-parameter model assuming a spherical source can recover the Einstein radius from the CFHT simulations with a precision of 7%. We apply a mask to the input data that noticeably enhances the robustness of the models facing environment problems, with a median convergence time of 4 minutes that could be easily reduced by a factor of 10 with more direct optimization techniques. From our results, we define selection contours in the parameter space, resulting in a completeness of 38% and a purity of 55% for the sample of 51 candidates accepted by our robot among the 325 preselected systems.

  3. Strong gravitational lensing and the stellar IMF of early-type galaxies

    NASA Astrophysics Data System (ADS)

    Leier, Dominik; Ferreras, Ignacio; Saha, Prasenjit; Charlot, Stéphane; Bruzual, Gustavo; La Barbera, Francesco

    2016-07-01

    Systematic variations of the initial mass function (IMF) in early-type galaxies, and their connection with possible drivers such as velocity dispersion or metallicity, have been much debated in recent years. Strong lensing over galaxy scales combined with photometric and spectroscopic data provides a powerful method to constrain the stellar mass-to-light ratio and hence the functional form of the IMF. We combine photometric and spectroscopic constraints from the latest set of population synthesis models of Charlot & Bruzual, including a varying IMF, with a non-parametric analysis of the lens masses of 18 ETGs from the SLACS survey, with velocity dispersions in the range 200-300 km s-1. We find that very bottom-heavy IMFs are excluded. However, the upper limit to the bimodal IMF slope (μ ≲ 2.2, accounting for a dark matter fraction of 20-30 per cent, where μ = 1.3 corresponds to a Kroupa-like IMF) is compatible at the 1σ level with constraints imposed by gravity-sensitive line strengths. A two-segment power-law parametrization of the IMF (Salpeter-like for high masses) is more constrained (Γ ≲ 1.5, where Γ is the power index at low masses) but requires a dark matter contribution of ≳25 per cent to reconcile the results with a Salpeter IMF. For a standard Milky Way-like IMF to be applicable, a significant dark matter contribution is required within 1Re. Our results reveal a large range of allowed IMF slopes, which, when interpreted as intrinsic scatter in the IMF properties of ETGs, could explain the recent results of Smith et al., who find Milky Way-like IMF normalizations in a few massive lensing ETGs.

  4. Strong Gravitational Lensing and the Stellar IMF of Early-type Galaxies

    NASA Astrophysics Data System (ADS)

    Leier, Dominik; Ferreras, Ignacio; Saha, Prasenjit; Charlot, Stéphane; Bruzual, Gustavo; La Barbera, Francesco

    2016-04-01

    Systematic variations of the IMF in early-type galaxies, and their connection with possible drivers such as velocity dispersion or metallicity, have been much debated in recent years. Strong lensing over galaxy scales combined with photometric and spectroscopic data provides a powerful method to constrain the stellar mass-to-light ratio and hence the functional form of the IMF. We combine photometric and spectroscopic constraints from the latest set of population synthesis models of Charlot & Bruzual, including a varying IMF, with a non-parametric analysis of the lens masses of 18 ETGs from the SLACS survey, with velocity dispersions in the range 200-300 km s-1. We find that very bottom-heavy IMFs are excluded. However, the upper limit to the bimodal IMF slope (μ ≲ 2.2, accounting for a dark matter fraction of 20-30%, where μ = 1.3 corresponds to a Kroupa-like IMF) is compatible at the 1 σ level with constraints imposed by gravity-sensitive line strengths. A two-segment power law parameterisation of the IMF (Salpeter-like for high masses) is more constrained (Γ ≲ 1.5, where Γ is the power index at low masses) but requires a dark matter contribution of ≲ 25% to reconcile the results with a Salpeter IMF. For a standard Milky Way-like IMF to be applicable, a significant dark matter contribution is required within 1Re. Our results reveal a large range of allowed IMF slopes, which, when interpreted as intrinsic scatter in the IMF properties of ETGs, could explain the recent results of Smith et al., who find Milky Way-like IMF normalisations in a few massive lensing ETGs.

  5. Some advanced testing techniques for concentrator photovoltaic cells and lenses

    SciTech Connect

    Wiczer, J.J.; Chaffin, R.J.; Hibray, R.E.

    1982-09-01

    The authors describe two separate test techniques for evaluating concentrator photovoltaic components. For convenient characterization of concentrator solar cells, they have developed a method for measuring the entire illuminated I-V curve of a photovoltaic cell with a single flash of intense simulated sunlight. This method reduces the heat input to the cell and the time required to test a cell, thus making possible quick indoor measurements of photovoltaic conversion efficiency at concentrated illumination levels without the use of elaborate cell mounting fixtures or heat sink attachments. The other test method provides a technique to analyze the spatially dependent, spectral distribution of intense sunlight collected and focused by lenses designed for use in photovoltaic concentrator systems. This information is important in the design of multijunction photovoltaic receivers, secondary concentrators, and in optimizing the performance of conventional silicon cell concentrator systems.

  6. Searching for Cooling Signatures in Strong Lensing Galaxy Clusters: Evidence Against Baryons Shaping the Matter Distribution in Cluster Cores

    NASA Astrophysics Data System (ADS)

    Blanchard, Peter; Bayliss, M.; McDonald, M.

    2013-01-01

    Despite the growing number of galaxy clusters being discovered which exhibit strong gravitational lensing, the process by which the mass density profile of these clusters becomes centrally concentrated enough to produce high strong lensing cross-sections is not well understood. It has been suggested that the baryonic condensation of the intracluster medium (ICM) due to cooling may drag dark matter to the cores and thus steepen the profile. If this were the case, one would expect to observe signatures of strong ICM cooling (e.g., steep X-ray cores, optical emission line nebulae, star formation) in and around the central brightest cluster galaxy. In this work, we search for such evidence of ICM cooling in the first large, well-defined sample of strong lensing selected galaxy clusters in the redshift range 0.1 < z < 0.6. Based on the known correlations between cooling rate and both optical emission line luminosity and specific star formation, as traced by [OII]λλ3727 emission and the 4000 angstrom break strength, respectively, we measure the fraction of clusters that have cooling signatures in a new sample of hundreds of strong lensing clusters, and compare this result to that in a control sample of thousands of optically-selected galaxy clusters. Our results argue against the ability of baryonic cooling in the cores of galaxy clusters to strongly modify the underlying dark matter potential, leading to an increase in strong lensing cross-sections. This work is supported in part by the NSF REU and DOD ASSURE programs under NSF grant no. 0754568 and by the Smithsonian Institution.

  7. Analytical discussion on strong gravitational lensing for a massive source with a f (R ) global monopole

    NASA Astrophysics Data System (ADS)

    Man, Jingyun; Cheng, Hongbo

    2015-07-01

    Here we investigate the gravitational lensing in the strong field limit of a Schwarzschild black hole with a solid deficit angle owing to a global monopole within the context of the f (R ) gravity theory. We obtain the expressions of the deflection angle and time delay in the forms of elliptic integrals and discuss the asymptotic behavior of the elliptic integrals to find the explicit formulas of the angle and time difference in the strong field limit. We show that the deflection angle and the time delay between multiple images are related not only to the monopole but also to the f (R ) correction ψ0 by taking the cosmological boundary into account. Some observables such as the minimum impact parameter, the angular separation, the relative magnification, and the compacted angular position are estimated as well. It is intriguing that a tiny modification on standard general relativity will make a remarkable deviation on the angle and the time lag, offering a significant way to explore some possible distinct signatures of the topological soliton and the correction of Einstein's general relativity.

  8. Magnification relations for Kerr lensing and testing cosmic censorship

    SciTech Connect

    Werner, M. C.; Petters, A. O.

    2007-09-15

    A Kerr black hole with mass parameter m and angular momentum parameter a acting as a gravitational lens gives rise to two images in the weak field limit. We study the corresponding magnification relations, namely, the signed and absolute magnification sums and the centroid up to post-Newtonian order. We show that there are post-Newtonian corrections to the total absolute magnification and centroid proportional to a/m, which is in contrast to the spherically symmetric case where such corrections vanish. Hence we also propose a new set of lensing observables for the two images involving these corrections, which should allow measuring a/m with gravitational lensing. In fact, the resolution capabilities needed to observe this for the Galactic black hole should in principle be accessible to current and near-future instrumentation. Since a/m>1 indicates a naked singularity, a most interesting application would be a test of the cosmic censorship conjecture. The technique used to derive the image properties is based on the degeneracy of the Kerr lens and a suitably displaced Schwarzschild lens at post-Newtonian order. A simple physical explanation for this degeneracy is also given.

  9. Discovery of a Very Bright Strongly Lensed Galaxy Candidate at z ≈ 7.6

    NASA Astrophysics Data System (ADS)

    Bradley, L. D.; Bouwens, R. J.; Ford, H. C.; Illingworth, G. D.; Jee, M. J.; Benítez, N.; Broadhurst, T. J.; Franx, M.; Frye, B. L.; Infante, L.; Motta, V.; Rosati, P.; White, R. L.; Zheng, W.

    2008-05-01

    Using Hubble Space Telescope (HST) and Spitzer IRAC imaging, we report the discovery of a very bright strongly lensed Lyman break galaxy (LBG) candidate at z ~ 7.6 in the field of the massive galaxy cluster Abell 1689 (z = 0.18). The galaxy candidate, which we refer to as A1689-zD1, shows a strong z850 - J110 break of at least 2.2 mag and is completely undetected (<1 σ) in HST Advanced Camera for Surveys (ACS) g475, r625, i775, and z850 data. These properties, combined with the very blue J110 - H160 and H160 - [ 4.5 μ m ] colors, are exactly the properties of an z ~ 7.6 LBG, and can only be reasonably fit by a star-forming galaxy at z = 7.6 +/- 0.4 (χ2ν = 1.1). Attempts to reproduce these properties with a model galaxy at z < 4 yield particularly poor fits (χ2ν >= 25). A1689-zD1 has an observed (lensed) magnitude of 24.7 AB (8 σ) in the NICMOS H160 band and is ~1.3 mag brighter than the brightest known z850-dropout galaxy. When corrected for the cluster magnification of ~9.3 at z ~ 7.6, the candidate has an intrinsic magnitude of H160 = 27.1 AB, or about an L* galaxy at z ~ 7.6. The source-plane deprojection shows that the star formation is occurring in compact knots of size lesssim300 pc. The best-fit stellar population synthesis models yield a median redshift of 7.6, stellar masses (1.6-3.9) × 109 M⊙, stellar ages 45-320 Myr, star formation rates lesssim7.6 M⊙ yr-1, and low reddening with AV <= 0.3. These properties are generally similar to those of LBGs found at z ~ 5-6. The inferred stellar ages suggest a formation redshift of z ~ 8-10 (tlesssim 0.63 Gyr). A1689-zD1 is the brightest observed, highly reliable z > 7.0 galaxy candidate found to date. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy under NASA contract NAS5-26555. Based on observations made with the Spitzer Space Telescope, which is

  10. DISCOVERY OF A STRONG LENSING GALAXY EMBEDDED IN A CLUSTER AT z = 1.62

    SciTech Connect

    Wong, Kenneth C.; Suyu, Sherry H.; Tran, Kim-Vy H.; Papovich, Casey J.; Momcheva, Ivelina G.; Brammer, Gabriel B.; Koekemoer, Anton M.; Brodwin, Mark; Gonzalez, Anthony H.; Kacprzak, Glenn G.; Rudnick, Gregory H.; Halkola, Aleksi

    2014-07-10

    We identify a strong lensing galaxy in the cluster IRC 0218 (also known as XMM-LSS J02182–05102) that is spectroscopically confirmed to be at z = 1.62, making it the highest-redshift strong lens galaxy known. The lens is one of the two brightest cluster galaxies and lenses a background source galaxy into an arc and a counterimage. With Hubble Space Telescope (HST) grism and Keck/LRIS spectroscopy, we measure the source redshift to be z {sub S} = 2.26. Using HST imaging in ACS/F475W, ACS/F814W, WFC3/F125W, and WFC3/F160W, we model the lens mass distribution with an elliptical power-law profile and account for the effects of the cluster halo and nearby galaxies. The Einstein radius is θ{sub E}=0.38{sub −0.01}{sup +0.02} arcsec (3.2{sub −0.1}{sup +0.2} kpc) and the total enclosed mass is M {sub tot}(<θ{sub E})=1.8{sub −0.1}{sup +0.2}×10{sup 11} M{sub ⊙}. We estimate that the cluster environment contributes ∼10% of this total mass. Assuming a Chabrier initial mass function (IMF), the dark matter fraction within θ{sub E} is f{sub DM}{sup Chab}=0.3{sub −0.3}{sup +0.1}, while a Salpeter IMF is marginally inconsistent with the enclosed mass (f{sub DM}{sup Salp}=−0.3{sub −0.5}{sup +0.2}). The total magnification of the source is μ{sub tot}=2.1{sub −0.3}{sup +0.4}. The source has at least one bright compact region offset from the source center. Emission from Lyα and [O III] are likely to probe different regions in the source.

  11. Strong gravitational lensing by an electrically charged black hole in Eddington-inspired Born-Infeld gravity

    NASA Astrophysics Data System (ADS)

    Sotani, Hajime; Miyamoto, Umpei

    2015-08-01

    We systematically examine the properties of null geodesics around an electrically charged, asymptotically flat black hole in Eddington-inspired Born-Infeld gravity, varying the electric charge of the black hole and the coupling constant in the theory. We find that the radius of the unstable circular orbit for a massless particle decreases with the coupling constant, if the value of the electrical charge is fixed. Additionally, we consider the strong gravitational lensing around such a black hole. We show that the deflection angle, the position angle of the relativistic images, and the magnification due to the light bending in strong gravitational field are quite sensitive to the parameters determining the black hole solution. Thus, through the accurate observations associated with the strong gravitational lensing, it might be possible to reveal the gravitational theory in a strong field regime.

  12. Observation and Confirmation of Six Strong-lensing Systems in the Dark Energy Survey Science Verification Data

    NASA Astrophysics Data System (ADS)

    Nord, B.; Buckley-Geer, E.; Lin, H.; Diehl, H. T.; Helsby, J.; Kuropatkin, N.; Amara, A.; Collett, T.; Allam, S.; Caminha, G. B.; De Bom, C.; Desai, S.; Dúmet-Montoya, H.; Pereira, M. Elidaiana da S.; Finley, D. A.; Flaugher, B.; Furlanetto, C.; Gaitsch, H.; Gill, M.; Merritt, K. W.; More, A.; Tucker, D.; Saro, A.; Rykoff, E. S.; Rozo, E.; Birrer, S.; Abdalla, F. B.; Agnello, A.; Auger, M.; Brunner, R. J.; Carrasco Kind, M.; Castander, F. J.; Cunha, C. E.; da Costa, L. N.; Foley, R. J.; Gerdes, D. W.; Glazebrook, K.; Gschwend, J.; Hartley, W.; Kessler, R.; Lagattuta, D.; Lewis, G.; Maia, M. A. G.; Makler, M.; Menanteau, F.; Niernberg, A.; Scolnic, D.; Vieira, J. D.; Gramillano, R.; Abbott, T. M. C.; Banerji, M.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carretero, J.; D’Andrea, C. B.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Frieman, J.; Gaztanaga, E.; Gruen, D.; Honscheid, K.; James, D. J.; Kuehn, K.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miquel, R.; Neilsen, E.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Walker, A. R.; Wester, W.; Zhang, Y.; The DES Collaboration

    2016-08-01

    We report the observation and confirmation of the first group- and cluster-scale strong gravitational lensing systems found in Dark Energy Survey data. Through visual inspection of data from the Science Verification season, we identified 53 candidate systems. We then obtained spectroscopic follow-up of 21 candidates using the Gemini Multi-object Spectrograph at the Gemini South telescope and the Inamori-Magellan Areal Camera and Spectrograph at the Magellan/Baade telescope. With this follow-up, we confirmed six candidates as gravitational lenses: three of the systems are newly discovered, and the remaining three were previously known. Of the 21 observed candidates, the remaining 15 either were not detected in spectroscopic observations, were observed and did not exhibit continuum emission (or spectral features), or were ruled out as lensing systems. The confirmed sample consists of one group-scale and five galaxy-cluster-scale lenses. The lensed sources range in redshift z ∼ 0.80–3.2 and in i-band surface brightness i SB ∼ 23–25 mag arcsec‑2 (2″ aperture). For each of the six systems, we estimate the Einstein radius θ E and the enclosed mass M enc, which have ranges θ E ∼ 5″–9″ and M enc ∼ 8 × 1012 to 6 × 1013 M ⊙, respectively. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  13. Observation and Confirmation of Six Strong-lensing Systems in the Dark Energy Survey Science Verification Data

    NASA Astrophysics Data System (ADS)

    Nord, B.; Buckley-Geer, E.; Lin, H.; Diehl, H. T.; Helsby, J.; Kuropatkin, N.; Amara, A.; Collett, T.; Allam, S.; Caminha, G. B.; De Bom, C.; Desai, S.; Dúmet-Montoya, H.; Pereira, M. Elidaiana da S.; Finley, D. A.; Flaugher, B.; Furlanetto, C.; Gaitsch, H.; Gill, M.; Merritt, K. W.; More, A.; Tucker, D.; Saro, A.; Rykoff, E. S.; Rozo, E.; Birrer, S.; Abdalla, F. B.; Agnello, A.; Auger, M.; Brunner, R. J.; Carrasco Kind, M.; Castander, F. J.; Cunha, C. E.; da Costa, L. N.; Foley, R. J.; Gerdes, D. W.; Glazebrook, K.; Gschwend, J.; Hartley, W.; Kessler, R.; Lagattuta, D.; Lewis, G.; Maia, M. A. G.; Makler, M.; Menanteau, F.; Niernberg, A.; Scolnic, D.; Vieira, J. D.; Gramillano, R.; Abbott, T. M. C.; Banerji, M.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carretero, J.; D’Andrea, C. B.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Frieman, J.; Gaztanaga, E.; Gruen, D.; Honscheid, K.; James, D. J.; Kuehn, K.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miquel, R.; Neilsen, E.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Walker, A. R.; Wester, W.; Zhang, Y.; The DES Collaboration

    2016-08-01

    We report the observation and confirmation of the first group- and cluster-scale strong gravitational lensing systems found in Dark Energy Survey data. Through visual inspection of data from the Science Verification season, we identified 53 candidate systems. We then obtained spectroscopic follow-up of 21 candidates using the Gemini Multi-object Spectrograph at the Gemini South telescope and the Inamori-Magellan Areal Camera and Spectrograph at the Magellan/Baade telescope. With this follow-up, we confirmed six candidates as gravitational lenses: three of the systems are newly discovered, and the remaining three were previously known. Of the 21 observed candidates, the remaining 15 either were not detected in spectroscopic observations, were observed and did not exhibit continuum emission (or spectral features), or were ruled out as lensing systems. The confirmed sample consists of one group-scale and five galaxy-cluster-scale lenses. The lensed sources range in redshift z ˜ 0.80–3.2 and in i-band surface brightness i SB ˜ 23–25 mag arcsec‑2 (2″ aperture). For each of the six systems, we estimate the Einstein radius θ E and the enclosed mass M enc, which have ranges θ E ˜ 5″–9″ and M enc ˜ 8 × 1012 to 6 × 1013 M ⊙, respectively. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  14. Shape profiles and orientation bias for weak and strong lensing cluster halos

    SciTech Connect

    Groener, A. M.; Goldberg, D. M.

    2014-11-10

    We study the intrinsic shape and alignment of isodensities of galaxy cluster halos extracted from the MultiDark MDR1 cosmological simulation. We find that the simulated halos are extremely prolate on small scales and increasingly spherical on larger ones. Due to this trend, analytical projection along the line of sight produces an overestimation of the concentration index as a decreasing function of radius, which we quantify by using both the intrinsic distribution of three-dimensional concentrations (c {sub 200}) and isodensity shape on weak and strong lensing scales. We find this difference to be ∼18% (∼9%) for low- (medium-)mass cluster halos with intrinsically low concentrations (c {sub 200} = 1-3), while we find virtually no difference for halos with intrinsically high concentrations. Isodensities are found to be fairly well aligned throughout the entirety of the radial scale of each halo population. However, major axes of individual halos have been found to deviate by as much as ∼30°. We also present a value-added catalog of our analysis results, which we have made publicly available to download.

  15. 30 CFR 27.38 - Tests to determine adequacy of windows and lenses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... lenses. 27.38 Section 27.38 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Tests to determine adequacy of windows and lenses. Impact tests. A 4-pound cylindrical weight with a one-inch diameter hemispherical striking surface will be dropped (free fall) to strike the window or...

  16. 30 CFR 27.38 - Tests to determine adequacy of windows and lenses.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... lenses. 27.38 Section 27.38 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Tests to determine adequacy of windows and lenses. Impact tests. A 4-pound cylindrical weight with a one-inch diameter hemispherical striking surface will be dropped (free fall) to strike the window or...

  17. 30 CFR 27.38 - Tests to determine adequacy of windows and lenses.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... lenses. 27.38 Section 27.38 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Tests to determine adequacy of windows and lenses. Impact tests. A 4-pound cylindrical weight with a one-inch diameter hemispherical striking surface will be dropped (free fall) to strike the window or...

  18. 30 CFR 27.38 - Tests to determine adequacy of windows and lenses.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... lenses. 27.38 Section 27.38 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Tests to determine adequacy of windows and lenses. Impact tests. A 4-pound cylindrical weight with a one-inch diameter hemispherical striking surface will be dropped (free fall) to strike the window or...

  19. CLASH: Extending galaxy strong lensing to small physical scales with distant sources highly magnified by galaxy cluster members

    SciTech Connect

    Grillo, C.; Christensen, L.; Gobat, R.; Balestra, I.; Nonino, M.; Biviano, A.; Mercurio, A.; Rosati, P.; Vanzella, E.; Graves, G.; Lemze, D.; Ford, H.; Bartelmann, M.; Benitez, N.; Bradley, L.; Coe, D.; Broadhurst, T.; Donahue, M.; and others

    2014-05-01

    We present a complex strong lensing system in which a double source is imaged five times by two early-type galaxies. We take advantage in this target of the extraordinary multi-band photometric data set obtained as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) program, complemented by the spectroscopic measurements of the VLT/VIMOS and FORS2 follow-up campaign. We use a photometric redshift value of 3.7 for the source and confirm spectroscopically the membership of the two lenses to the galaxy cluster MACS J1206.2–0847 at redshift 0.44. We exploit the excellent angular resolution of the HST/ACS images to model the two lenses in terms of singular isothermal sphere profiles and derive robust effective velocity dispersion values of 97 ± 3 and 240 ± 6 km s{sup –1}. Interestingly, the total mass distribution of the cluster is also well characterized by using only the local information contained in this lensing system, which is located at a projected distance of more than 300 kpc from the cluster luminosity center. According to our best-fitting lensing and composite stellar population models, the source is magnified by a total factor of 50 and has a luminous mass of approximately (1.0 ± 0.5) × 10{sup 9} M {sub ☉} (assuming a Salpeter stellar initial mass function). By combining the total and luminous mass estimates of the two lenses, we measure luminous over total mass fractions projected within the effective radii of 0.51 ± 0.21 and 0.80 ± 0.32. Remarkably, with these lenses we can extend the analysis of the mass properties of lens early-type galaxies by factors that are approximately two and three times smaller than previously done with regard to, respectively, velocity dispersion and luminous mass. The comparison of the total and luminous quantities of our lenses with those of astrophysical objects with different physical scales, like massive early-type galaxies and dwarf spheroidals, reveals the potential of studies of this kind for

  20. Experiment design for through-focus testing of intraocular lenses

    NASA Astrophysics Data System (ADS)

    Millán, María. S.; Alba-Bueno, Francisco; Vega, Fidel

    2013-11-01

    Eye models to test intraocular lenses (IOLs) in an optical bench are commonly designed in agreement with the ISO 11979-2 and 11979-9 standard requirements. However, modifications to the ISO eye model have been proposed to test IOLs in conditions closer to real human eye. Wavefront analysis and aberration characterization, wavelength dependence, efficiency, off-axis performance and imaging degradation under certain amount of misalignment can thus be measured in vitro. The main parts of the system to test IOLs are: the illumination system and object test, the eye model including the IOL immersed in a wet cell and a microscope assembled to a sensor that magnifies and captures the aerial image of the object formed by the eye model. A problem concerning the simultaneous variation of defocus and magnification arises when using the microscope to capture out-of-focus images in a through-focus study. Using the eye model, we study the problem of implementing a through-focus measurement of the imaging quality of an IOL. We find a solution based on geometrical optics and compare it with other proposals reported in the literature. The effects on the measurement of the Modulation Transfer Function and the Point Spread Function are predicted. Experimental results are obtained and discussed.

  1. SHELS: TESTING WEAK-LENSING MAPS WITH REDSHIFT SURVEYS

    SciTech Connect

    Geller, Margaret J.; Kurtz, Michael J.; Fabricant, Daniel G.; Dell'Antonio, Ian P.; Ramella, Massimo E-mail: mkurtz@cfa.harvard.ed E-mail: ian@het.brown.ed

    2010-02-01

    Weak-lensing surveys are emerging as an important tool for the construction of 'mass-selected' clusters of galaxies. We evaluate both the efficiency and completeness of a weak-lensing selection by combining a dense, complete redshift survey, the Smithsonian Hectospec Lensing Survey (SHELS), with a weak-lensing map from the Deep Lens Survey (DLS). SHELS includes 11,692 redshifts for galaxies with R <= 20.6 in the 4 deg{sup 2} DLS field; the survey is a solid basis for identifying massive clusters of galaxies with redshift z approx< 0.55. The range of sensitivity of the redshift survey is similar to the range for the DLS convergence map. Only four of the 12 convergence peaks with signal to noise >=3.5 correspond to clusters of galaxies with M approx> 1.7 x 10{sup 14} M{sub sun}. Four of the eight massive clusters in SHELS are detected in the weak-lensing map yielding a completeness of approx50%. We examine the seven known extended cluster X-ray sources in the DLS field: three can be detected in the weak-lensing map, three should not be detected without boosting from superposed large-scale structure, and one is mysteriously undetected even though its optical properties suggest that it should produce a detectable lensing signal. Taken together, these results underscore the need for more extensive comparisons among different methods of massive cluster identification.

  2. 30 CFR 27.38 - Tests to determine adequacy of windows and lenses.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Tests to determine adequacy of windows and lenses. Impact tests. A 4-pound cylindrical weight with a one... in its mounting or the equivalent thereof at or near the center. At least three out of four...

  3. SEARCHING FOR COOLING SIGNATURES IN STRONG LENSING GALAXY CLUSTERS: EVIDENCE AGAINST BARYONS SHAPING THE MATTER DISTRIBUTION IN CLUSTER CORES

    SciTech Connect

    Blanchard, Peter K.; Bayliss, Matthew B.; McDonald, Michael; Dahle, Hakon; Gladders, Michael D.; Sharon, Keren; Mushotzky, Richard

    2013-07-20

    The process by which the mass density profile of certain galaxy clusters becomes centrally concentrated enough to produce high strong lensing (SL) cross-sections is not well understood. It has been suggested that the baryonic condensation of the intracluster medium (ICM) due to cooling may drag dark matter to the cores and thus steepen the profile. In this work, we search for evidence of ongoing ICM cooling in the first large, well-defined sample of SL selected galaxy clusters in the range 0.1 < z < 0.6. Based on known correlations between the ICM cooling rate and both optical emission line luminosity and star formation, we measure, for a sample of 89 SL clusters, the fraction of clusters that have [O II]{lambda}{lambda}3727 emission in their brightest cluster galaxy (BCG). We find that the fraction of line-emitting BCGs is constant as a function of redshift for z > 0.2 and shows no statistically significant deviation from the total cluster population. Specific star formation rates, as traced by the strength of the 4000 A break, D{sub 4000}, are also consistent with the general cluster population. Finally, we use optical imaging of the SL clusters to measure the angular separation, R{sub arc}, between the arc and the center of mass of each lensing cluster in our sample and test for evidence of changing [O II] emission and D{sub 4000} as a function of R{sub arc}, a proxy observable for SL cross-sections. D{sub 4000} is constant with all values of R{sub arc}, and the [O II] emission fractions show no dependence on R{sub arc} for R{sub arc} > 10'' and only very marginal evidence of increased weak [O II] emission for systems with R{sub arc} < 10''. These results argue against the ability of baryonic cooling associated with cool core activity in the cores of galaxy clusters to strongly modify the underlying dark matter potential, leading to an increase in SL cross-sections.

  4. Spitzer Imaging of Strongly lensed Herschel-selected Dusty Star-forming Galaxies

    NASA Astrophysics Data System (ADS)

    Ma, Brian; Cooray, Asantha; Calanog, J. A.; Nayyeri, H.; Timmons, N.; Casey, C.; Baes, M.; Chapman, S.; Dannerbauer, H.; da Cunha, E.; De Zotti, G.; Dunne, L.; Farrah, D.; Fu, Hai; Gonzalez-Nuevo, J.; Magdis, G.; Michałowski, M. J.; Oteo, I.; Riechers, D. A.; Scott, D.; Smith, M. W. L.; Wang, L.; Wardlow, J.; Vaccari, M.; Viaene, S.; Vieira, J. D.

    2015-11-01

    We present the rest-frame optical spectral energy distribution (SED) and stellar masses of six Herschel-selected gravitationally lensed dusty, star-forming galaxies (DSFGs) at 1 < z < 3. These galaxies were first identified with Herschel/SPIRE imaging data from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). The targets were observed with Spitzer/IRAC at 3.6 and 4.5 μm. Due to the spatial resolution of the IRAC observations at the level of 2″, the lensing features of a background DSFG in the near-infrared are blended with the flux from the foreground lensing galaxy in the IRAC imaging data. We make use of higher resolution Hubble/WFC3 or Keck/NIRC2 Adaptive Optics imaging data to fit light profiles of the foreground lensing galaxy (or galaxies) as a way to model the foreground components, in order to successfully disentangle the foreground lens and background source flux densities in the IRAC images. The flux density measurements at 3.6 and 4.5 μm, once combined with Hubble/WFC3 and Keck/NIRC2 data, provide important constraints on the rest-frame optical SED of the Herschel-selected lensed DSFGs. We model the combined UV- to millimeter-wavelength SEDs to establish the stellar mass, dust mass, star formation rate, visual extinction, and other parameters for each of these Herschel-selected DSFGs. These systems have inferred stellar masses in the range 8 × 1010-4 × 1011 M⊙ and star formation rates of around 100 M⊙ yr-1. This puts these lensed submillimeter systems well above the SFR-M* relation observed for normal star-forming galaxies at similar redshifts. The high values of SFR inferred for these systems are consistent with a major merger-driven scenario for star formation.

  5. Precise Strong Lensing Mass Modeling of Four Hubble Frontier Field Clusters and a Sample of Magnified High-redshift Galaxies

    NASA Astrophysics Data System (ADS)

    Kawamata, Ryota; Oguri, Masamune; Ishigaki, Masafumi; Shimasaku, Kazuhiro; Ouchi, Masami

    2016-03-01

    We conduct precise strong lensing mass modeling of four Hubble Frontier Field (HFF) clusters, Abell 2744, MACS J0416.1-2403, MACS J0717.5+3745, and MACS J1149.6+2223, for which HFF imaging observations are completed. We construct a refined sample of more than 100 multiple images for each cluster by taking advantage of the full-depth HFF images, and conduct mass modeling using the glafic software, which assumes simply parametrized mass distributions. Our mass modeling also exploits a magnification constraint from the lensed SN Ia HFF14Tom for Abell 2744 and positional constraints from the multiple images S1-S4 of the lensed supernova SN Refsdal for MACS J1149.6+2223. We find that our best-fitting mass models reproduce the observed image positions with rms errors of ˜0.″4, which are smaller than rms errors in previous mass modeling that adopted similar numbers of multiple images. Our model predicts a new image of SN Refsdal with a relative time delay and magnification that are fully consistent with a recent detection of reappearance. We then construct catalogs of z ˜ 6-9 dropout galaxies behind the four clusters and estimate magnification factors for these dropout galaxies with our best-fitting mass models. The dropout sample from the four cluster fields contains ˜120 galaxies at z ≳ 6, about 20 of which are predicted to be magnified by a factor of more than 10. Some of the high-redshift galaxies detected in the HFF have lensing-corrected magnitudes of MUV ˜ -15 to -14. Our analysis demonstrates that the HFF data indeed offer an ideal opportunity to study faint high-redshift galaxies. All lensing maps produced from our mass modeling will be made available on the Space Telescope Science Institute website (https://archive.stsci.edu/prepds/frontier/lensmodels/).

  6. Rest-Frame Optical Spectra of Three Strongly Lensed Galaxies at z~2

    SciTech Connect

    Hainline, Kevin N.; Shapley, Alice E.; Kornei, Katherine A.; Pettini, Max; Buckley-Geer, Elizabeth; Allam, Sahar S.; Tucker, Douglas L.; /Fermilab

    2009-06-01

    We present Keck II NIRSPEC rest-frame optical spectra for three recently discovered lensed galaxies: the Cosmic Horseshoe (z = 2.38), the Clone (z = 2.00), and SDSS J090122.37+181432.3 (z = 2.26). The boost in signal-to-noise ratio (S/N) from gravitational lensing provides an unusually detailed view of the physical conditions in these objects. A full complement of high S/N rest-frame optical emission lines is measured, spanning from rest frame 3600 to 6800 {angstrom}, including robust detections of fainter lines such as H{gamma}, [S II]{lambda}6717,6732, and in one instance [Ne III]{lambda}3869. SDSS J090122.37+181432.3 shows evidence for active galactic nucleus activity, and therefore we focus our analysis on star-forming regions in the Cosmic Horseshoe and the Clone. For these two objects, we estimate a wide range of physical properties. Current lensing models for the Cosmic Horseshoe and the Clone allow us to correct the measured H{alpha} luminosity and calculated star formation rate. Metallicities have been estimated with a variety of indicators, which span a range of values of 12+ log(O/H) = 8.3-8.8, between {approx}0.4 and {approx}1.5 of the solar oxygen abundance. Dynamical masses were computed from the H{alpha} velocity dispersions and measured half-light radii of the reconstructed sources. A comparison of the Balmer lines enabled measurement of dust reddening coefficients. Variations in the line ratios between the different lensed images are also observed, indicating that the spectra are probing different regions of the lensed galaxies. In all respects, the lensed objects appear fairly typical of ultraviolet-selected star-forming galaxies at z {approx} 2. The Clone occupies a position on the emission-line diagnostic diagram of [O III]/H{beta} versus [N II]/H{alpha} that is offset from the locations of z {approx} 0 galaxies. Our new NIRSPEC measurements may provide quantitative insights into why high-redshift objects display such properties. From the [S II

  7. The BOSS Emission-line Lens Survey. III. Strong Lensing of Lyα Emitters by Individual Galaxies

    NASA Astrophysics Data System (ADS)

    Shu, Yiping; Bolton, Adam S.; Kochanek, Christopher S.; Oguri, Masamune; Pérez-Fournon, Ismael; Zheng, Zheng; Mao, Shude; Montero-Dorta, Antonio D.; Brownstein, Joel R.; Marques-Chaves, Rui; Ménard, Brice

    2016-06-01

    We introduce the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey GALaxy-Lyα EmitteR sYstems (BELLS GALLERY) Survey, which is a Hubble Space Telescope program to image a sample of galaxy-scale strong gravitational lens candidate systems with high-redshift Lyα emitters (LAEs) as the background sources. The goal of the BELLS GALLERY Survey is to illuminate dark substructures in galaxy-scale halos by exploiting the small-scale clumpiness of rest-frame far-UV emission in lensed LAEs, and to thereby constrain the slope and normalization of the substructure-mass function. In this paper, we describe in detail the spectroscopic strong-lens selection technique, which is based on methods adopted in the previous Sloan Lens ACS (SLACS) Survey, BELLS, and SLACS for the Masses Survey. We present the BELLS GALLERY sample of the 21 highest-quality galaxy–LAE candidates selected from ≈ 1.4× {10}6 galaxy spectra in the BOSS of the Sloan Digital Sky Survey III. These systems consist of massive galaxies at redshifts of approximately 0.5 strongly lensing LAEs at redshifts from 2–3. The compact nature of LAEs makes them an ideal probe of dark substructures, with a substructure-mass sensitivity that is unprecedented in other optical strong-lens samples. The magnification effect from lensing will also reveal the structure of LAEs below 100 pc scales, providing a detailed look at the sites of the most concentrated unobscured star formation in the universe. The source code used for candidate selection is available for download as a part of this release.

  8. Superconducting Focusing Lenses for the SSR1 Cryomodule of PXIE Test Stand at Fermilab

    SciTech Connect

    DiMarco, J.; Tartaglia, M.; Terechkine, I.

    2016-01-01

    Five solenoid-based focusing lenses designed for use inside the SSR1 cryomodule of the PXIE test stand at Fermilab have been fabricated and tested. In addition to a focusing solenoid, each lens is equipped with a set of windings that generate magnetic field in the transverse plane and can be used in the steering dipole mode or as a skew quadrupole corrector. The lenses will be installed between superconducting cavities in the cryomodule, so getting sufficiently low fringe magnetic field was one of the main design requirements. Beam dynamics simulations indicated a need for high accuracy positioning of the lenses in the cryomodule, which triggered a study towards understanding uncertainties of the magnetic axis position relative to the geometric features of the lens. This report summarizes the efforts towards certification of the lenses, including results of performance tests, fringe field data, and uncertainty of the magnetic axis position.

  9. High Resolution Molecular Gas and Star Formation in the Strongly Lensed z~2 Galaxy SDSS J0901+1814

    NASA Astrophysics Data System (ADS)

    Sharon, Chelsea; Baker, Andrew; Tagore, Amitpal; Rivera, Jesus; Keeton, Charles; Lutz, Dieter; Tacconi, Linda; Wilner, David; Shapley, Alice

    2015-08-01

    In order to understand the evolution of high-redshift galaxies, it is important to accurately characterize the molecular gas that fuels their star formation. Comparisons to low-redshift galaxies using well-known correlations like the Schmidt-Kennicutt relation have been complicated by several factors, including differences in line excitation for the molecular gas tracer and a lack of spatially resolved mapping at high redshift. While access to the CO(1-0) line near the peak of the cosmic star formation rate density (z~2-3) at the Robert C. Byrd Green Bank Telescope and the Karl G. Jansky Very Large Array has allowed for direct comparisons between high- and low-resdhift galaxies on the Schmidt-Kennicutt relation free from potential excitation biases, many of these analyses are based on galaxy-wide average CO line measurements which may hide spatial variation on sub-galactic scales. For gravitationally lensed galaxies, integrated measurements disguising true gas conditions are particularly a concern due to the effects of differential lensing. We will present high-resolution observations of the CO(1-0), CO(3-2), CO(7-6), CI, H-alpha, and NII lines in the z=2.26 galaxy SDSS J0901+1814. With these observations we are able to place the galaxy on the true surface density version of the Schmidt-Kennicutt relation and evaluate its excitation bias, as well as examine the galaxy's spatial distribution of the molecular gas physical conditions. Since this galaxy is strongly lensed, we will also be able to evaluate how characterizations of this source differ when the effects of gravitational lensing are not accounted for.

  10. Rest-Frame Optical Spectra of Three Strongly Lensed Galaxies at z ~ 2

    NASA Astrophysics Data System (ADS)

    Hainline, Kevin N.; Shapley, Alice E.; Kornei, Katherine A.; Pettini, Max; Buckley-Geer, Elizabeth; Allam, Sahar S.; Tucker, Douglas L.

    2009-08-01

    We present Keck II NIRSPEC rest-frame optical spectra for three recently discovered lensed galaxies: the Cosmic Horseshoe (z = 2.38), the Clone (z = 2.00), and SDSS J090122.37+181432.3 (z = 2.26). The boost in signal-to-noise ratio (S/N) from gravitational lensing provides an unusually detailed view of the physical conditions in these objects. A full complement of high S/N rest-frame optical emission lines is measured, spanning from rest frame 3600 to 6800 Å, including robust detections of fainter lines such as Hγ, [S II]λ6717,6732, and in one instance [Ne III]λ3869. SDSS J090122.37+181432.3 shows evidence for active galactic nucleus activity, and therefore we focus our analysis on star-forming regions in the Cosmic Horseshoe and the Clone. For these two objects, we estimate a wide range of physical properties. Current lensing models for the Cosmic Horseshoe and the Clone allow us to correct the measured Hα luminosity and calculated star formation rate. Metallicities have been estimated with a variety of indicators, which span a range of values of 12+ log(O/H) = 8.3-8.8, between ~0.4 and ~1.5 of the solar oxygen abundance. Dynamical masses were computed from the Hα velocity dispersions and measured half-light radii of the reconstructed sources. A comparison of the Balmer lines enabled measurement of dust reddening coefficients. Variations in the line ratios between the different lensed images are also observed, indicating that the spectra are probing different regions of the lensed galaxies. In all respects, the lensed objects appear fairly typical of ultraviolet-selected star-forming galaxies at z ~ 2. The Clone occupies a position on the emission-line diagnostic diagram of [O III]/Hβ versus [N II]/Hα that is offset from the locations of z ~ 0 galaxies. Our new NIRSPEC measurements may provide quantitative insights into why high-redshift objects display such properties. From the [S II] line ratio, high electron densities (~1000 cm-3) are inferred compared

  11. Analytic Kerr black hole lensing for equatorial observers in the strong deflection limit

    SciTech Connect

    Bozza, V.; De Luca, F.; Scarpetta, G.; Sereno, M.

    2005-10-15

    In this paper we present an analytical treatment of gravitational lensing by Kerr black holes in the limit of very large deflection angles, restricting to observers in the equatorial plane. We accomplish our objective starting from the Schwarzschild black hole and adding corrections up to second order in the black hole spin. This is sufficient to provide a full description of all caustics and the inversion of lens mapping for sources near them. On the basis of these formulae we argue that relativistic images of low mass x-ray binaries around Sgr A* are very likely to be seen by future x-ray interferometry missions.

  12. Testing the MOND paradigm of modified dynamics with galaxy-galaxy gravitational lensing.

    PubMed

    Milgrom, Mordehai

    2013-07-26

    The MOND paradigm of modified dynamics predicts that the asymptotic gravitational potential of an isolated, bounded (baryonic) mass, M, is ϕ(r)=(MGa0)1/2ln(r). Relativistic MOND theories predict that the lensing effects of M are dictated by ϕ(r) as general-relativity lensing is dictated by the Newtonian potential. Thus MOND predicts that the asymptotic Newtonian potential deduced from galaxy-galaxy gravitational lensing will have (1) a logarithmic r dependence, and (2) a normalization (parametrized standardly as 2σ2) that depends only on M: σ=(MGa0/4)1/4. I compare these predictions with recent results of galaxy-galaxy lensing, and find agreement on all counts. For the “blue”-lenses subsample (“spiral” galaxies) MOND reproduces the observations well with an r′-band M/Lr′∼(1–3)(M/L)⊙, and for “red” lenses (“elliptical” galaxies) with M/Lr′∼(3–6)(M/L)⊙, both consistent with baryons only. In contradistinction, Newtonian analysis requires, typically, M/Lr′∼130(M/L)⊙, bespeaking a mass discrepancy of a factor ∼40. Compared with the staple, rotation-curve tests, MOND is here tested in a wider population of galaxies, through a different phenomenon, using relativistic test objects, and is probed to several-times-lower accelerations–as low as a few percent of a0. PMID:23931350

  13. IDCS J1426.5+3508: COSMOLOGICAL IMPLICATIONS OF A MASSIVE, STRONG LENSING CLUSTER AT z = 1.75

    SciTech Connect

    Gonzalez, Anthony H.; Fedeli, Cosimo; Mancone, Conor; Stanford, S. Adam; Zeimann, Greg; Brodwin, Mark; Dey, Arjun; Eisenhardt, Peter R. M.; Stern, Daniel

    2012-07-10

    The galaxy cluster IDCS J1426.5+3508 at z = 1.75 is the most massive galaxy cluster yet discovered at z > 1.4 and the first cluster at this epoch for which the Sunyaev-Zel'Dovich effect has been observed. In this paper, we report on the discovery with Hubble Space Telescope imaging of a giant arc associated with this cluster. The curvature of the arc suggests that the lensing mass is nearly coincident with the brightest cluster galaxy, and the color is consistent with the arc being a star-forming galaxy. We compare the constraint on M{sub 200} based upon strong lensing with Sunyaev-Zel'Dovich results, finding that the two are consistent if the redshift of the arc is z {approx}> 3. Finally, we explore the cosmological implications of this system, considering the likelihood of the existence of a strongly lensing galaxy cluster at this epoch in a {Lambda}CDM universe. While the existence of the cluster itself can potentially be accommodated if one considers the entire volume covered at this redshift by all current high-redshift cluster surveys, the existence of this strongly lensed galaxy greatly exacerbates the long-standing giant arc problem. For standard {Lambda}CDM structure formation and observed background field galaxy counts this lens system should not exist. Specifically, there should be no giant arcs in the entire sky as bright in F814W as the observed arc for clusters at z {>=} 1.75, and only {approx}0.3 as bright in F160W as the observed arc. If we relax the redshift constraint to consider all clusters at z {>=} 1.5, the expected number of giant arcs rises to {approx}15 in F160W, but the number of giant arcs of this brightness in F814W remains zero. These arc statistic results are independent of the mass of IDCS J1426.5+3508. We consider possible explanations for this discrepancy.

  14. A STRONGLY LENSED MASSIVE ULTRACOMPACT QUIESCENT GALAXY AT z {approx} 2.4 IN THE COSMOS/UltraVISTA FIELD

    SciTech Connect

    Muzzin, Adam; Labbe, Ivo; Franx, Marijn; Holt, J.; Szomoru, Daniel; Van de Sande, Jesse; Van Dokkum, Pieter; Brammer, Gabriel; Marchesini, Danilo; Stefanon, Mauro; Buitrago, F.; Dunlop, James; Caputi, K. I.; Fynbo, J. P. U.; Milvang-Jensen, Bo; Le Fevre, Olivier; McCracken, Henry J.

    2012-12-20

    We report the discovery of a massive ultracompact quiescent galaxy that has been strongly lensed into multiple images by a foreground galaxy at z 0.960. This system was serendipitously discovered as a set of extremely K{sub s} -bright high-redshift galaxies with red J - K{sub s} colors using new data from the UltraVISTA YJHK{sub s} near-infrared survey. The system was also previously identified as an optically faint lens/source system using the COSMOS Advanced Camera for Surveys (ACS) imaging by Faure et al. Photometric redshifts for the three brightest images of the source galaxy determined from 27-band photometry place the source at z = 2.4 {+-} 0.1. We provide an updated lens model for the system that is a good fit to the positions and morphologies of the galaxies in the ACS image. The lens model implies that the magnification of the three brightest images is a factor of 4-5. We use the lens model, combined with the K{sub s} -band image, to constrain the size and Sersic profile of the galaxy. The best-fit model is an ultracompact galaxy (R{sub e} = 0.64{sup +0.08}{sub -0.18} kpc, lensing-corrected), with a Sersic profile that is intermediate between a disk and a bulge profile (n 2.2{sup +2.3}{sub -{sub 0.9}}), albeit with considerable uncertainties on the Sersic profile. We present aperture photometry for the source galaxy images that have been corrected for flux contamination from the central lens. The best-fit stellar population model is a massive galaxy (log(M{sub star}/M{sub Sun }) = 10.8{sup +0.1}{sub -0.1}, lensing-corrected) with an age of 1.0{sup +1.0}{sub -0.4} Gyr, moderate dust extinction (A{sub v} = 0.8{sup +0.5}{sub -0.6}), and a low specific star formation rate (log(SSFR) <-11.0 yr{sup -1}). This is typical of massive ''red-and-dead'' galaxies at this redshift and confirms that this source is the first bona fide strongly lensed massive ultracompact quiescent galaxy to be discovered. We conclude with a discussion of the prospects of finding a larger

  15. Analytic solutions for Navarro-Frenk-White lens models in the strong lensing regime for low characteristic convergences

    NASA Astrophysics Data System (ADS)

    Dúmet-Montoya, H. S.; Caminha, G. B.; Makler, M.

    2013-12-01

    Context. The Navarro-Frenk-White (NFW) density profile is often used to model gravitational lenses. For κs ≲ 0.1 (where κs is a parameter that defines the normalization of the NFW lens potential) - corresponding to galaxy and galaxy group mass scales - high numerical precision is required to accurately compute several quantities in the strong lensing regime. Aims: We obtain analytic solutions for several lensing quantities for circular NFW models and their elliptical (ENFW) and pseudo-elliptical (PNFW) extensions, on the typical scales where gravitational arcs are expected to be formed, in the κs ≲ 0.1 limit, by establishing their domain of validity. Methods: We approximate the deflection angle of the circular NFW model and derive analytic expressions for the convergence and shear for the PNFW and ENFW models. We obtain the constant distortion curves (including the tangential critical curve), which are used to define the domain of validity of the approximations, by employing a figure-of-merit to compare with the exact numerical solutions. We compute the deformation cross section as a further check of the validity of the approximations. Results: We derive analytic solutions for iso-convergence contours and constant distortion curves for the models considered here. We also obtain the deformation cross section, which is given in closed form for the circular NFW model and in terms of a one-dimensional integral for the elliptical ones. In addition, we provide a simple expression for the ellipticity of the iso-convergence contours of the pseudo-elliptical models and the connection of characteristic convergences among the PNFW and ENFW models. Conclusions: We conclude that the set of solutions derived here is generally accurate for κs ≲ 0.1. For low ellipticities, values up to κs ≃ 0.18 are allowed. On the other hand, the mapping among PNFW and the ENFW models is valid up to κs ≃ 0.4. The solutions derived in this work can be used to speed up numerical

  16. Sub-kiloparsec Imaging of Cool Molecular Gas in Two Strongly Lensed Dusty, Star-forming Galaxies

    NASA Astrophysics Data System (ADS)

    Spilker, J. S.; Aravena, M.; Marrone, D. P.; Béthermin, M.; Bothwell, M. S.; Carlstrom, J. E.; Chapman, S. C.; Collier, J. D.; de Breuck, C.; Fassnacht, C. D.; Galvin, T.; Gonzalez, A. H.; González-López, J.; Grieve, K.; Hezaveh, Y.; Ma, J.; Malkan, M.; O'Brien, A.; Rotermund, K. M.; Strandet, M.; Vieira, J. D.; Weiss, A.; Wong, G. F.

    2015-10-01

    We present spatially resolved imaging obtained with the Australia Telescope Compact Array (ATCA) of three CO lines in two high-redshift gravitationally lensed dusty star-forming galaxies, discovered by the South Pole Telescope. Strong lensing allows us to probe the structure and dynamics of the molecular gas in these two objects, at z = 2.78 and z = 5.66, with effective source-plane resolution of less than 1 kpc. We model the lensed emission from multiple CO transitions and the dust continuum in a consistent manner, finding that the cold molecular gas as traced by low-J CO always has a larger half-light radius than the 870 μm dust continuum emission. This size difference leads to up to 50% differences in the magnification factor for the cold gas compared to dust. In the z = 2.78 galaxy, these CO observations confirm that the background source is undergoing a major merger, while the velocity field of the other source is more complex. We use the ATCA CO observations and comparable resolution Atacama Large Millimeter/submillimeter Array dust continuum imaging of the same objects to constrain the CO-H2 conversion factor with three different procedures, finding good agreement between the methods and values consistent with those found for rapidly star-forming systems. We discuss these galaxies in the context of the star formation—gas mass surface density relation, noting that the change in emitting area with observed CO transition must be accounted for when comparing high-redshift galaxies to their lower redshift counterparts.

  17. Gravitational lens models based on submillimeter array imaging of Herschel -selected strongly lensed sub-millimeter galaxies at z > 1.5

    SciTech Connect

    Bussmann, R. S.; Gurwell, M. A.; Pérez-Fournon, I.; Amber, S.; Calanog, J.; De Bernardis, F.; Wardlow, J.; Dannerbauer, H.; Harris, A. I.; Krips, M.; Lapi, A.; Maiolino, R.; Omont, A.; Riechers, D.; Baker, A. J.; Birkinshaw, M.; Bock, J.; and others

    2013-12-10

    Strong gravitational lenses are now being routinely discovered in wide-field surveys at (sub-)millimeter wavelengths. We present Submillimeter Array (SMA) high-spatial resolution imaging and Gemini-South and Multiple Mirror Telescope optical spectroscopy of strong lens candidates discovered in the two widest extragalactic surveys conducted by the Herschel Space Observatory: the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). From a sample of 30 Herschel sources with S {sub 500} > 100 mJy, 21 are strongly lensed (i.e., multiply imaged), 4 are moderately lensed (i.e., singly imaged), and the remainder require additional data to determine their lensing status. We apply a visibility-plane lens modeling technique to the SMA data to recover information about the masses of the lenses as well as the intrinsic (i.e., unlensed) sizes (r {sub half}) and far-infrared luminosities (L {sub FIR}) of the lensed submillimeter galaxies (SMGs). The sample of lenses comprises primarily isolated massive galaxies, but includes some groups and clusters as well. Several of the lenses are located at z {sub lens} > 0.7, a redshift regime that is inaccessible to lens searches based on Sloan Digital Sky Survey spectroscopy. The lensed SMGs are amplified by factors that are significantly below statistical model predictions given the 500 μm flux densities of our sample. We speculate that this may reflect a deficiency in our understanding of the intrinsic sizes and luminosities of the brightest SMGs. The lensed SMGs span nearly one decade in L {sub FIR} (median L {sub FIR} = 7.9 × 10{sup 12} L {sub ☉}) and two decades in FIR luminosity surface density (median Σ{sub FIR} = 6.0 × 10{sup 11} L {sub ☉} kpc{sup –2}). The strong lenses in this sample and others identified via (sub-)mm surveys will provide a wealth of information regarding the astrophysics of galaxy formation and evolution over a wide range in redshift.

  18. Direct Observation of Cosmic Strings Via Their Strong Gravitational Lensing Effect. 1. Predictions for High Resolution Imaging Surveys

    SciTech Connect

    Gasparini, Maria Alice; Marshall, Phil; Treu, Tommaso; Morganson, Eric; Dubath, Florian; /Santa Barbara, KITP

    2007-11-14

    We use current theoretical estimates for the density of long cosmic strings to predict the number of strong gravitational lensing events in astronomical imaging surveys as a function of angular resolution and survey area. We show that angular resolution is the single most important factor, and that interesting limits on the dimensionless string tension G{mu}/c{sup 2} can be obtained by existing and planned surveys. At the resolution of the Hubble Space Telescope (0'.14), it is sufficient to survey of order a square degree -- well within reach of the current HST archive -- to probe the regime G{mu}/c{sup 2} {approx} 10{sup -8}. If lensing by cosmic strings is not detected, such a survey would improve the limit on the string tension by an order of magnitude on that available from the cosmic microwave background. At the resolution (0'.028) attainable with the next generation of large ground based instruments, both in the radio and the infra-red with adaptive optics, surveying a sky area of order ten square degrees will allow us to probe the G{mu}/c{sup 2} {approx} 10{sup -9} regime. These limits will not be improved significantly by increasing the solid angle of the survey.

  19. Reflection from the strong gravity regime in a lensed quasar at redshift z = 0.658.

    PubMed

    Reis, R C; Reynolds, M T; Miller, J M; Walton, D J

    2014-03-13

    The co-evolution of a supermassive black hole with its host galaxy through cosmic time is encoded in its spin. At z > 2, supermassive black holes are thought to grow mostly by merger-driven accretion leading to high spin. It is not known, however, whether below z ≈ 1 these black holes continue to grow by coherent accretion or in a chaotic manner, though clear differences are predicted in their spin evolution. An established method of measuring the spin of black holes is through the study of relativistic reflection features from the inner accretion disk. Owing to their greater distances from Earth, there has hitherto been no significant detection of relativistic reflection features in a moderate-redshift quasar. Here we report an analysis of archival X-ray data together with a deep observation of a gravitationally lensed quasar at z = 0.658. The emission originates within three or fewer gravitational radii from the black hole, implying a spin parameter (a measure of how fast the black hole is rotating) of a = 0.87(+0.08)(-0.15) at the 3σ confidence level and a > 0.66 at the 5σ level. The high spin found here is indicative of growth by coherent accretion for this black hole, and suggests that black-hole growth at 0.5 ≤ z ≤ 1 occurs principally by coherent rather than chaotic accretion episodes. PMID:24598545

  20. J0454-0309: evidence of a strong lensing fossil group falling into a poor galaxy cluster

    NASA Astrophysics Data System (ADS)

    Schirmer, M.; Suyu, S.; Schrabback, T.; Hildebrandt, H.; Erben, T.; Halkola, A.

    2010-05-01

    Aims: We have discovered a strong lensing fossil group (J0454) projected near the well-studied cluster MS0451-0305. Using the large amount of available archival data, we compare J0454 to normal groups and clusters. A highly asymmetric image configuration of the strong lens enables us to study the substructure of the system. Methods: We used multicolour Subaru/Suprime-Cam and CFHT/Megaprime imaging, together with Keck spectroscopy to identify member galaxies. A VLT/FORS2 spectrum was taken to determine the redshifts of the brightest elliptical and the lensed arc. Using HST/ACS images, we determined the group's weak lensing signal and modelled the strong lens system. This is the first time that a fossil group is analysed with lensing methods. The X-ray luminosity and temperature were derived from XMM-Newton data. Results: J0454 is located at z = 0.26, with a gap of 2.5 mag between the brightest and second brightest galaxies within half the virial radius. Outside a radius of 1.5 Mpc, we find two filaments extending over 4 Mpc, and within we identify 31 members spectroscopically and 33 via the red sequence with i < 22 mag. They segregate into spirals (σ_v = 590 km s-1) and a central concentration of ellipticals (σ_v = 480 km s-1), establishing a morphology-density relation. Weak lensing and cluster richness relations yield consistent values of r200 = 810-850 kpc and M200 = (0.75-0.90) × 1014 M_⊙. The brightest group galaxy (BGG) is inconsistent with the dynamic centre of J0454. It strongly lenses a galaxy at z = 2.1 ± 0.3, and we model the lens with a pseudo-isothermal elliptical mass distribution. A high external shear, and a discrepancy between the Einstein radius and the weak lensing velocity dispersion requires that the BGG must be offset from J0454's dark halo centre by at least 90-130 kpc. The X-ray halo is offset by 24 ± 16 kpc from the BGG, shows no signs of a cooling flow and can be fit by a single β-model. With LX = (1.4 ± 0.2) × 1043 erg s-1 J0454

  1. Fabrication of Compound Refractive X-ray Lenses Using LIGA Process and Performance Tests

    SciTech Connect

    Lee, Jin Pyoung; Kim, Guk Bae; Kim, Jong Hyun; Chang, Suk Sang; Lee, Sang Joon

    2007-01-19

    Recent advances of X-ray microscopy technology enable the visualization of some micro/nano-scale objects which optical microscopy and electron microscopy cannot be used to observe. The X-ray microscopy can be applied to observe the internal structure of a thicker sample than the electron microscopy can, and its spatial resolution is higher than that of the optical microscopy. Moreover, it has a powerful element specific imaging ability. For further improving the X-ray microscope, it is indispensable to make X-ray optics for focusing X-rays more effectively. Recently, various X-ray lenses such as diffraction lenses of FZP(Fresnel zone plate) and spatter-sliced FZT, total reflection lenses of K-B(Kirkpatrick-Baez) mirror and Wolter mirror, and refractive lens of CRL(compound refractive lens) were introduced. Compared with the other types of lenses, CRL is easy to fabricate and handle. In this study, we designed and fabricated various types of CRLs using LIGA(LIthographie, Galvanoformung, Abformtechnik) process, and used PMMA(Poly(methyl methacrylate)) material as the material of CRL. Their performances are tested with varying parameters such as parabolic/kinoform shape, radius of curvature, wall thickness between adjacent lenses, and width of lenses. The performance tests were carried out by using a simple synchrotron X-ray imaging method. The tests results revealed that hard x-rays could be condensed well by the CRL of PMMA material at the focal point we expect We captured sample images one-dimensionally magnified by CRLs. Furthermore, we found which parameter is more effective for enhancing focus efficiency and which parameter should be considered more carefully in the fabrication process of LIGA.

  2. TESTING WEAK-LENSING MAPS WITH REDSHIFT SURVEYS: A SUBARU FIELD

    SciTech Connect

    Kurtz, Michael J.; Geller, Margaret J.; Fabricant, Daniel G.; Utsumi, Yousuke; Miyazaki, Satoshi; Dell'Antonio, Ian P. E-mail: mgeller@cfa.harvard.edu E-mail: yousuke.utsumi@nao.ac.jp E-mail: ian@het.brown.edu

    2012-05-10

    We use a dense redshift survey in the foreground of the Subaru GTO2deg{sup 2} weak-lensing field (centered at {alpha}{sub 2000} = 16{sup h}04{sup m}44{sup s}; {delta}{sub 2000} = 43 Degree-Sign 11'24'') to assess the completeness and comment on the purity of massive halo identification in the weak-lensing map. The redshift survey (published here) includes 4541 galaxies; 4405 are new redshifts measured with the Hectospec on the MMT. Among the weak-lensing peaks with a signal-to-noise greater than 4.25, 2/3 correspond to individual massive systems; this result is essentially identical to the Geller et al. test of the Deep Lens Survey (DLS) field F2. The Subaru map, based on images in substantially better seeing than the DLS, enables detection of less massive halos at fixed redshift as expected. We demonstrate that the procedure adopted by Miyazaki et al. for removing some contaminated peaks from the weak-lensing map improves agreement between the lensing map and the redshift survey in the identification of candidate massive systems.

  3. Fast Variability and Millimeter/IR Flares in GRMHD Models of Sgr A* from Strong-field Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Chan, Chi-kwan; Psaltis, Dimitrios; Özel, Feryal; Medeiros, Lia; Marrone, Daniel; Saḑowski, Aleksander; Narayan, Ramesh

    2015-10-01

    We explore the variability properties of long, high-cadence general relativistic magnetohydrodynamic (GRMHD) simulations across the electromagnetic spectrum using an efficient, GPU-based radiative transfer algorithm. We focus on both standard and normal evolution (SANE) and magnetically arrested disk (MAD) simulations with parameters that successfully reproduce the time-averaged spectral properties of Sgr A* and the size of its image at 1.3 mm. We find that the SANE models produce short-timescale variability with amplitudes and power spectra that closely resemble those inferred observationally. In contrast, MAD models generate only slow variability at lower flux levels. Neither set of models shows any X-ray flares, which most likely indicates that additional physics, such as particle acceleration mechanisms, need to be incorporated into the GRMHD simulations to account for them. The SANE models show strong, short-lived millimeter/infrared (IR) flares, with short (≲1 hr) time lags between the millimeter and IR wavelengths, that arise from the combination of short-lived magnetic flux tubes and strong-field gravitational lensing near the horizon. Such events provide a natural explanation for the observed IR flares with no X-ray counterparts.

  4. Gravitational lensing from compact bodies: Analytical results for strong and weak deflection limits

    SciTech Connect

    Amore, Paolo; Cervantes, Mayra; De Pace, Arturo; Fernandez, Francisco M.

    2007-04-15

    We develop a nonperturbative method that yields analytical expressions for the deflection angle of light in a general static and spherically symmetric metric. The method works by introducing into the problem an artificial parameter, called {delta}, and by performing an expansion in this parameter to a given order. The results obtained are analytical and nonperturbative because they do not correspond to a polynomial expression in the physical parameters. Already to first order in {delta} the analytical formulas obtained using our method provide at the same time accurate approximations both at large distances (weak deflection limit) and at distances close to the photon sphere (strong deflection limit). We have applied our technique to different metrics and verified that the error is at most 0.5% for all regimes. We have also proposed an alternative approach which provides simpler formulas, although with larger errors.

  5. Strong and Weak Lensing United II: the Cluster Mass Distribution of the Most X-ray Luminous Cluster RX J1347.5-1145

    SciTech Connect

    Bradac, M.

    2005-04-13

    We have shown that the cluster-mass reconstruction method which combines strong and weak gravitational lensing data, developed in the first paper in the series, successfully reconstructs the mass distribution of a simulated cluster. In this paper we apply the method to the ground-based high-quality multi-colour data of RX J1347.5-1145, the most X-ray luminous cluster to date. A new analysis of the cluster core on very deep, multi-colour data analysis of VLT/FORS data reveals many more arc candidates than previously known for this cluster. The combined strong and weak lensing reconstruction confirms that the cluster is indeed very massive. If the redshift and identification of the multiple-image system as well as the redshift estimates of the source galaxies used for weak lensing are correct, we determine the enclosed cluster mass in a cylinder to M(< 360h{sup -1}kpc) = (1.2 {+-} 0.3) x 10{sup 15}M{circle_dot}. In addition the reconstructed mass distribution follows the distribution found with independent methods (X-ray measurements, SZ). With higher resolution (e.g. HST imaging data) more reliable multiple imaging information can be obtained and the reconstruction can be improved to accuracies greater than what is currently possible with weak and strong lensing techniques.

  6. Strong and weak lensing united: II. The cluster mass distribution of the most X-ray luminous cluster RX J1347.5-1145

    SciTech Connect

    Bradač, M.; Erben, T.; Schneider, P.; Hildebrandt, H.; Lombardi, M.; Schirmer, M.; Miralles, J. -M.; Clowe, D.; Schindler, S.

    2005-07-01

    We have shown that the cluster-mass reconstruction method which combines strong and weak gravitational lensing data, developed in the first paper in the series, successfully reconstructs the mass distribution of a simulated cluster. In this paper we apply the method to the ground-based high-quality multi-colour data of RX J1347.5-1145 , the most X-ray luminous cluster to date. A new analysis of the cluster core on very deep, multi-colour data analysis of VLT/FORS data reveals many more arc candidates than previously known for this cluster. The combined strong and weak lensing reconstruction confirms that the cluster is indeed very massive. If the redshift and identification of the multiple-image system as well as the redshift estimates of the source galaxies used for weak lensing are correct, we determine the enclosed cluster mass in a cylinder to M(<360 h -1 kpc)= (1.2± 0.3) x 1015 M. In addition the reconstructed mass distribution follows the distribution found with independent methods (X-ray measurements, SZ). With higher resolution (e.g. HST imaging data) more reliable multiple imaging information can be obtained and the reconstruction can be improved to accuracies greater than what is currently possible with weak and strong lensing techniques.

  7. A Stellar Velocity Dispersion for a Strongly-lensed, Intermediate-mass Quiescent Galaxy at z=2.8

    NASA Astrophysics Data System (ADS)

    Hill, Allison. R.; Muzzin, Adam; Franx, Marijn; van de Sande, Jesse

    2016-03-01

    Measuring stellar velocity dispersions of quiescent galaxies beyond z˜ 2 is observationally challenging. Such measurements require near-infrared spectra with a continuum detection of at least moderate signal to noise, often necessitating long integrations. In this paper, we present deep X-Shooter spectroscopy of one of only two known gravitationally lensed massive quiescent galaxies at z\\gt 2. This galaxy is quadruply imaged, with the brightest images magnified by a factor of ˜5. The total exposure time of our data is 9.8 hr on-source; however, the magnification, and the slit placement encompassing two images, provides a total equivalent exposure time of 215 hr. From this deep spectrum we measure a redshift of ({z}{spec}=2.756+/- 0.001), making this one of the highest redshift quiescent galaxies that is spectroscopically confirmed. We simultaneously fit both the spectroscopic and photometric data to determine stellar population parameters and conclude that this galaxy is relatively young ({560}-80+100 {Myr}), of intermediate mass ({log} {M}*/{M}⊙ ={10.59}-0.05+0.04), consistent with low dust content ({A}V={0.20}-0.20+0.26), and has quenched only relatively recently. This recent quenching is confirmed by strong Balmer absorption, particularly Hδ (H{δ }A={6.66}-0.92+0.96). Remarkably, this proves that at least some intermediate-mass galaxies have already quenched as early as z˜ 2.8. Additionally, we have measured a velocity dispersion of (σ =187+/- 43 {km} {{{s}}}-1), making this the highest-redshift quiescent galaxy with a dispersion measurement. We confirm that this galaxy falls on the same mass fundamental plane (MFP) as galaxies at z = 2.2, consistent with little to no evolution in the MFP up to z = 2.8. Overall this galaxy is proof of the existence of intermediate-mass quenched galaxies in the distant universe, and that lensing is a powerful tool for determining their properties with improved accuracy.

  8. CMB Lensing Cross Correlations

    NASA Astrophysics Data System (ADS)

    Bleem, Lindsey

    2014-03-01

    A new generation of experiments designed to conduct high-resolution, low-noise observations of the Cosmic Microwave Background (CMB)--including ACTpol, Planck, POLARBEAR and SPTpol--are producing exquisite measurements of the gravitational lensing of the CMB. Such measurements, covering large fractions of the sky, provide detailed maps of the projected mass distribution extending to the surface of the CMB's last scattering. Concurrently, a large number of deep, wide-area imaging and spectroscopic surveys (e.g., the Dark Energy Survey (DES),WISE all-sky survey, Subaru HyperSuprimeCam Survey, LSST, MS-DESI, BigBoss, etc.) are, or will soon be, providing maps of the distribution of galaxies in the Universe. Correlations of such tracer populations with lensing data allows new probes of where and how galaxies form in the dark matter skeleton of the Universe. Recent correlations of maps of galaxy and quasar densities with lensing convergence maps have produced significant measurements of galaxy bias. The near-term prospect for improvements in such measurements is notable as more precise lensing data from CMB polarization experiments will help to break cosmological and astrophysical parameter degeneracies. Work by the Planck, SPT, and POLARBEAR collaborations has also focused on the correlation of the Cosmic Infrared Background (CIB) with CMB lensing convergence maps. This correlation is particularly strong as the redshifts of the CIB and CMB lensing kernel are well matched. Such correlations probe high-redshift structure, constraining models of star-formation and the characteristic mass scale for halos hosting CIB galaxies and have also been used to demonstrate the first detection of CMB B-mode polarization--an important milestone in CMB observations. Finally, combining galaxy number density, cosmic shear and CMB lensing maps has the potential to provide valuable systematic tests for upcoming cosmological results from large optical surveys such as LSST.

  9. 30 CFR 18.66 - Tests of windows and lenses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... withdrawal of the samples from the oven they will be immersed in water having a temperature between 15 °C... mounting, or the equivalent thereof, at or near the center. Three of four samples shall withstand without... alternate methods at the discretion of MSHA. (b) Thermal-shock tests. Four samples of the window or...

  10. 30 CFR 18.66 - Tests of windows and lenses.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... withdrawal of the samples from the oven they will be immersed in water having a temperature between 15 °C... mounting, or the equivalent thereof, at or near the center. Three of four samples shall withstand without... alternate methods at the discretion of MSHA. (b) Thermal-shock tests. Four samples of the window or...

  11. 30 CFR 18.66 - Tests of windows and lenses.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... withdrawal of the samples from the oven they will be immersed in water having a temperature between 15 °C... mounting, or the equivalent thereof, at or near the center. Three of four samples shall withstand without... alternate methods at the discretion of MSHA. (b) Thermal-shock tests. Four samples of the window or...

  12. 30 CFR 18.66 - Tests of windows and lenses.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... withdrawal of the samples from the oven they will be immersed in water having a temperature between 15 °C... mounting, or the equivalent thereof, at or near the center. Three of four samples shall withstand without... alternate methods at the discretion of MSHA. (b) Thermal-shock tests. Four samples of the window or...

  13. 30 CFR 18.66 - Tests of windows and lenses.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... withdrawal of the samples from the oven they will be immersed in water having a temperature between 15 °C... mounting, or the equivalent thereof, at or near the center. Three of four samples shall withstand without... alternate methods at the discretion of MSHA. (b) Thermal-shock tests. Four samples of the window or...

  14. A HIGHLY ELONGATED PROMINENT LENS AT z = 0.87: FIRST STRONG-LENSING ANALYSIS OF EL GORDO

    SciTech Connect

    Zitrin, Adi; Menanteau, Felipe; Hughes, John P.; Coe, Dan; Barrientos, L. Felipe; Infante, Leopoldo; Mandelbaum, Rachel

    2013-06-10

    We present the first strong-lensing (SL) analysis of the galaxy cluster ACT-CL J0102-4915 (El Gordo), in recent HST/ACS images, revealing a prominent strong lens at a redshift of z = 0.87. This finding adds to the already-established unique properties of El Gordo: it is the most massive, hot, X-ray luminous, and bright Sunyaev-Zeldovich effect cluster at z {approx}> 0.6, and the only {sup b}ullet{sup -}like merging cluster known at these redshifts. The lens consists of two merging massive clumps, where, for a source redshift of z{sub s} {approx} 2, each clump exhibits only a small, separate critical area, with a total area of 0.69 {+-} 0.11{open_square}' over the two clumps. For a higher source redshift, z{sub s} {approx} 4, the critical curves of the two clumps merge together into one bigger and very elongated lens (axis ratio {approx_equal} 5.5), enclosing an effective area of 1.44 {+-} 0.22{open_square}'. The critical curves continue expanding with increasing redshift so that for high-redshift sources (z{sub s} {approx}> 9) they enclose an area of {approx}1.91 {+-} 0.30{open_square}' (effective {theta}{sub e} {approx_equal} 46.''8 {+-} 3.''7) and a mass of 6.09 {+-} 1.04 Multiplication-Sign 10{sup 14} M{sub Sun }. According to our model, the area of high magnification ({mu} > 10) for such high-redshift sources is {approx_equal}1.2{open_square}', and the area with {mu} > 5 is {approx_equal}2.3{open_square}', making El Gordo a compelling target for studying the high-redshift universe. We obtain a strong lower limit on the total mass of El Gordo, {approx}> 1.7 Multiplication-Sign 10{sup 15} M{sub Sun} from the SL regime alone, suggesting a total mass of roughly M{sub 200} {approx} 2.3 Multiplication-Sign 10{sup 15} M{sub Sun }. Our results should be revisited when additional spectroscopic and HST imaging data are available.

  15. Automated optical testing of LWIR objective lenses using focal plane array sensors

    NASA Astrophysics Data System (ADS)

    Winters, Daniel; Erichsen, Patrik; Domagalski, Christian; Peter, Frank; Heinisch, Josef; Dumitrescu, Eugen

    2012-10-01

    The image quality of today's state-of-the-art IR objective lenses is constantly improving while at the same time the market for thermography and vision grows strongly. Because of increasing demands on the quality of IR optics and increasing production volumes, the standards for image quality testing increase and tests need to be performed in shorter time. Most high-precision MTF testing equipment for the IR spectral bands in use today relies on the scanning slit method that scans a 1D detector over a pattern in the image generated by the lens under test, followed by image analysis to extract performance parameters. The disadvantages of this approach are that it is relatively slow, it requires highly trained operators for aligning the sample and the number of parameters that can be extracted is limited. In this paper we present lessons learned from the R and D process on using focal plane array (FPA) sensors for testing of long-wave IR (LWIR, 8-12 m) optics. Factors that need to be taken into account when switching from scanning slit to FPAs are e.g.: the thermal background from the environment, the low scene contrast in the LWIR, the need for advanced image processing algorithms to pre-process camera images for analysis and camera artifacts. Finally, we discuss 2 measurement systems for LWIR lens characterization that we recently developed with different target applications: 1) A fully automated system suitable for production testing and metrology that uses uncooled microbolometer cameras to automatically measure MTF (on-axis and at several o-axis positions) and parameters like EFL, FFL, autofocus curves, image plane tilt, etc. for LWIR objectives with an EFL between 1 and 12mm. The measurement cycle time for one sample is typically between 6 and 8s. 2) A high-precision research-grade system using again an uncooled LWIR camera as detector, that is very simple to align and operate. A wide range of lens parameters (MTF, EFL, astigmatism, distortion, etc.) can be

  16. Test of general relativity and measurement of the lense-thirring effect with two earth satellites

    PubMed

    Ciufolini; Pavlis; Chieppa; Fernandes-Vieira; Perez-Mercader

    1998-03-27

    The Lense-Thirring effect, a tiny perturbation of the orbit of a particle caused by the spin of the attracting body, was accurately measured with the use of the data of two laser-ranged satellites, LAGEOS and LAGEOS II, and the Earth gravitational model EGM-96. The parameter &mgr;, which measures the strength of the Lense-Thirring effect, was found to be 1.1 +/- 0.2; general relativity predicts &mgr; identical with 1. This result represents an accurate test and measurement of one of the fundamental predictions of general relativity, that the spin of a body changes the geometry of the universe by generating space-time curvature. PMID:9516109

  17. CLASH-VLT: A highly precise strong lensing model of the galaxy cluster RXC J2248.7-4431 (Abell S1063) and prospects for cosmography

    NASA Astrophysics Data System (ADS)

    Caminha, G. B.; Grillo, C.; Rosati, P.; Balestra, I.; Karman, W.; Lombardi, M.; Mercurio, A.; Nonino, M.; Tozzi, P.; Zitrin, A.; Biviano, A.; Girardi, M.; Koekemoer, A. M.; Melchior, P.; Meneghetti, M.; Munari, E.; Suyu, S. H.; Umetsu, K.; Annunziatella, M.; Borgani, S.; Broadhurst, T.; Caputi, K. I.; Coe, D.; Delgado-Correal, C.; Ettori, S.; Fritz, A.; Frye, B.; Gobat, R.; Maier, C.; Monna, A.; Postman, M.; Sartoris, B.; Seitz, S.; Vanzella, E.; Ziegler, B.

    2016-03-01

    Aims: We perform a comprehensive study of the total mass distribution of the galaxy cluster RXC J2248.7-4431 (z = 0.348) with a set of high-precision strong lensing models, which take advantage of extensive spectroscopic information on many multiply lensed systems. In the effort to understand and quantify inherent systematics in parametric strong lensing modelling, we explore a collection of 22 models in which we use different samples of multiple image families, different parametrizations of the mass distribution and cosmological parameters. Methods: As input information for the strong lensing models, we use the Cluster Lensing And Supernova survey with Hubble (CLASH) imaging data and spectroscopic follow-up observations, with the VIsible Multi-Object Spectrograph (VIMOS) and Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT), to identify and characterize bona fide multiple image families and measure their redshifts down to mF814W ≃ 26. A total of 16 background sources, over the redshift range 1.0-6.1, are multiply lensed into 47 images, 24 of which are spectroscopically confirmed and belong to ten individual sources. These also include a multiply lensed Lyman-α blob at z = 3.118. The cluster total mass distribution and underlying cosmology in the models are optimized by matching the observed positions of the multiple images on the lens plane. Bayesian Markov chain Monte Carlo techniques are used to quantify errors and covariances of the best-fit parameters. Results: We show that with a careful selection of a large sample of spectroscopically confirmed multiple images, the best-fit model can reproduce their observed positions with a rms scatter of 0.̋3 in a fixed flat ΛCDM cosmology, whereas the lack of spectroscopic information or the use of inaccurate photometric redshifts can lead to biases in the values of the model parameters. We find that the best-fit parametrization for the cluster total mass distribution is composed of an

  18. Resolving the High-energy Universe with Strong Gravitational Lensing: The Case of PKS 1830-211

    NASA Astrophysics Data System (ADS)

    Barnacka, Anna; Geller, Margaret J.; Dell'Antonio, Ian P.; Benbow, Wystan

    2015-08-01

    Gravitational lensing is a potentially powerful tool for elucidating the origin of gamma-ray emission from distant sources. Cosmic lenses magnify the emission from distant sources and produce time delays between mirage images. Gravitationally induced time delays depend on the position of the emitting regions in the source plane. The Fermi/LAT telescope continuously monitors the entire sky and detects gamma-ray flares, including those from gravitationally lensed blazars. Therefore, temporal resolution at gamma-ray energies can be used to measure these time delays, which, in turn, can be used to resolve the origin of the gamma-ray flares spatially. We provide a guide to the application and Monte Carlo simulation of three techniques for analyzing these unresolved light curves: the autocorrelation function, the double power spectrum, and the maximum peak method. We apply these methods to derive time delays from the gamma-ray light curve of the gravitationally lensed blazar PKS 1830-211. The result of temporal analysis combined with the properties of the lens from radio observations yield an improvement in spatial resolution at gamma-ray energies by a factor of 10,000. We analyze four active periods. For two of these periods the emission is consistent with origination from the core, and for the other two the data suggest that the emission region is displaced from the core by more than ˜1.5 kpc. For the core emission, the gamma-ray time delays, 23+/- 0.5 {days} and 19.7+/- 1.2 days, are consistent with the radio time delay of {26}-5+4 days.

  19. The impact of strong gravitational lensing on observed Lyman-break galaxy numbers at 4 ≤ z ≤ 8 in the GOODS and the XDF blank fields

    NASA Astrophysics Data System (ADS)

    Barone-Nugent, R. L.; Wyithe, J. S. B.; Trenti, M.; Treu, T.; Oesch, P.; Bouwens, R.; Illingworth, G. D.; Schmidt, K. B.

    2015-06-01

    Detections of Lyman-break galaxies (LBGs) at high-redshift are affected by gravitational lensing induced by foreground deflectors not only in galaxy clusters, but also in blank fields. We quantify the impact of strong magnification in the samples of B435, V606, i775 and z850 & Y105 dropouts (4 ≲ z ≲ 8) observed in the eXtreme Deep Field (XDF) and the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) fields by investigating the proximity of dropouts to foreground objects. We find that ˜6 per cent of bright z ˜ 7 LBGs (m_{H_{160}}<26) have been strongly lensed (μ > 2) by foreground objects. This fraction decreases from ˜3.5 per cent at z ˜ 6 to ˜1.5 per cent at z ˜ 4. Since the observed fraction of strongly lensed LBGs is a function of the shape of the luminosity function (LF), it can be used to derive Schechter parameters, α and M⋆, independently from galaxy number counts. Our magnification bias analysis yields Schechter-function parameters in close agreement with those determined from galaxy counts albeit with larger uncertainties. Extrapolation of our analysis to z ≳ 8 suggests that surveys with JWST, WFIRST and Euclid should find excess LBGs at the bright end, over an intrinsic exponential cutoff. Finally, we highlight how the magnification bias measurement near the XDF detection limit can be used to probe the population of galaxies beyond this limit. Preliminary results suggest that the magnification bias at MUV ˜ -18 is weaker than expected if α ≲ -1.7 extends well below the current detection limits. This could imply a flattening of the LF at MUV ≳ -16.5. However, selection effects and completeness estimates are difficult to quantify precisely. Thus, we do not rule out a steep LF extending to MUV ≳ -15.

  20. The 8 O'Clock Arc: A Serendipitous Discovery of a Strongly Lensed Lyman Break Galaxy in the SDSS DR4 Imaging Data

    SciTech Connect

    Allam, Sahar S.; Tucker, Douglas L.; Lin, Huan; Diehl, H.Thomas; Annis, James; Buckley-Geer, Elizabeth J.; Frieman, Joshua A.; /Fermilab /Chicago U., Astron. Astrophys. Ctr.

    2006-11-01

    We report on the serendipitous discovery of the brightest Lyman Break Galaxy (LBG) currently known, a galaxy at z = 2.73 that is being strongly lensed by the z = 0.38 Luminous Red Galaxy (LRG) SDSS J002240.91+143110.4. The arc of this gravitational lens system, which we have dubbed the ''8 o'clock arc'' due to its time of discovery, was initially identified in the imaging data of the Sloan Digital Sky Survey Data Release 4 (SDSS DR4); followup observations on the Astrophysical Research Consortium (ARC) 3.5m telescope at Apache Point Observatory confirmed the lensing nature of this system and led to the identification of the arc's spectrum as that of an LBG. The arc has a spectrum and a redshift remarkably similar to those of the previous record-holder for brightest LBG (MS 1512-cB58, a.k.a ''cB58''), but, with an estimated total magnitude of (g,r,i) = (20.0,19.2,19.0) and surface brightness of ({mu}{sub g}, {mu}{sub r}, {mu}{sub i}) = (23.3, 22.5, 22.3) mag arcsec{sup -2}, the 8 o'clock arc is thrice as bright. The 8 o'clock arc, which consists of three lensed images of the LBG, is 162{sup o}(9.6'') long and has a length-to-width ratio of 6:1. A fourth image of the LBG--a counter-image--can also be identified in the ARC 3.5m g-band images. A simple lens model for the system assuming a singular isothermal ellipsoid potential yields an Einstein radius of {theta}{sub Ein} = 2.91'' {+-} 0.14'', a total mass for the lensing LRG (within the 10.6 {+-} 0.5 h{sup -1} kpc enclosed by the lensed images) of 1.04 x 10{sup 12} h{sup -1} M{sub {circle_dot}}, and a magnification factor for the LBG of 12.3{sub -3.6}{sup +15}. The LBG itself is intrinsically quite luminous ({approx} 6 x L{sub *}) and shows indications of massive recent star formation, perhaps as high as 160 h{sup -1} M{sub {circle_dot}} yr{sup -1}.

  1. Hubble Space Telescope Observations of a Spectacular New Strong-Lensing Galaxy Cluster: MACS J1149.5+2223 at z = 0.544

    NASA Astrophysics Data System (ADS)

    Smith, Graham P.; Ebeling, Harald; Limousin, Marceau; Kneib, Jean-Paul; Swinbank, A. M.; Ma, Cheng-Jiun; Jauzac, Mathilde; Richard, Johan; Jullo, Eric; Sand, David J.; Edge, Alastair C.; Smail, Ian

    2009-12-01

    We present Advanced Camera for Surveys observations of MACS J1149.5+2223, an X-ray luminous galaxy cluster at z = 0.544 discovered by the Massive Cluster Survey. The data reveal at least seven multiply imaged galaxies, three of which we have confirmed spectroscopically. One of these is a spectacular face-on spiral galaxy at z = 1.491, the four images of which are gravitationally magnified by 8 lsim μ lsim 23. We identify this as an L sstarf (MB sime -20.7), disk-dominated (B/T lsim 0.5) galaxy, forming stars at ~6 M sun yr-1. We use a robust sample of multiply imaged galaxies to constrain a parameterized model of the cluster mass distribution. In addition to the main cluster dark matter halo and the bright cluster galaxies, our best model includes three galaxy-group-sized halos. The relative probability of this model is P(N halo = 4)/P(N halo < 4) >= 1012 where N halo is the number of cluster/group-scale halos. In terms of sheer number of merging cluster/group-scale components, this is the most complex strong-lensing cluster core studied to date. The total cluster mass and fraction of that mass associated with substructures within R <= 500 kpc, are measured to be M tot = (6.7 ± 0.4) × 1014 M sun and f sub = 0.25 ± 0.12, respectively. Our model also rules out recent claims of a flat density profile at gsim7σ confidence, thus highlighting the critical importance of spectroscopic redshifts of multiply imaged galaxies when modeling strong-lensing clusters. Overall our results attest to the efficiency of X-ray selection in finding the most powerful cluster lenses, including complicated merging systems.

  2. Strong lensing analysis of PLCK G004.5-19.5, a Planck-discovered cluster hosting a radio relic at z = 0.52

    NASA Astrophysics Data System (ADS)

    Sifón, Cristóbal; Menanteau, Felipe; Hughes, John P.; Carrasco, Mauricio; Barrientos, L. Felipe

    2014-02-01

    Context. The recent discovery of a large number of galaxy clusters using the Sunyaev-Zel'dovich (SZ) effect has opened a new era on the study of the most massive clusters in the Universe. Multiwavelength analyses are required to understand the properties of these new sets of clusters, which are a sensitive probe of cosmology. Aims: We aim for a multiwavelength characterization of PLCK G004.5-19.5, one of the most massive X-ray validated SZ effect-selected galaxy clusters discovered by the Planck satellite. Methods: We have observed PLCK G004.5-19.5 with GMOS on the 8.1 m-Gemini South Telescope for optical imaging and spectroscopy, and performed a strong lensing analysis. We also searched for associated radio emission in published catalogs. Results: An analysis of the optical images confirms that this is a massive cluster, with a dominant central galaxy and an accompanying red sequence of galaxies, plus a 14″-long strong lensing arc. Longslit spectroscopy of six cluster members shows that the cluster is at z = 0.516 ± 0.002. We also targeted the strongly lensed arc, and found zarc = 1.601. We use LensTool to carry out a strong lensing analysis, from which we measure a median Einstein radius θE(zs = 1.6) ≃ 30″ and estimate an enclosed mass ME = 2.45-0.47+0.45 × 1014 M⊙. By extrapolating a Navarro-Frenk-White profile, we find a total mass M500SL = 4.0-1.0+2.1 × 1014 M⊙. We also include a constraint on the mass from previous X-ray observations, which yields a slightly higher mass, M500SL+X = 6.7-1.3+2.6 × 1014 M⊙, consistent with the value from strong lensing alone. Intermediate-resolution radio images from the TIFR GMRT Sky Survey at 150 MHz reveal that PLCK G004.5-19.5 hosts a powerful radio relic on scales ≲500 kpc. Emission at the same location is also detected in low-resolution images at 843 MHz and 1.4 GHz. This is one of the higher redshift radio relics known to date. Based on observations obtained at the Gemini Observatory, which is operated

  3. Intermediate Strength Gravitational Lensing

    SciTech Connect

    Irwin, John

    2005-03-17

    Weak lensing is found in the correlations of shear in {approx}10{sup 4} galaxy images, strong lensing is detected by the obvious distortion of a single galaxy image, whereas intermediate lensing requires detection of less obvious curvature in several neighboring galaxies. Small impact-parameter lensing causes a sextupole distortion whose orientation is correlated with the quadrupole distortion (shear). By looking within a field for the spatial correlation of this sextupole-quadrupole correlation, an intermediate lensing regime is observed. This technique requires correction for the sextupole as well as the quadrupole content of the PSF. We remove the HST PSF and uncover intermediate lensing in the Hubble deep fields. Correlations of the type expected are found.

  4. Testing the lognormality of the galaxy and weak lensing convergence distributions from Dark Energy Survey maps

    NASA Astrophysics Data System (ADS)

    Clerkin, L.; Kirk, D.; Manera, M.; Lahav, O.; Abdalla, F.; Amara, A.; Bacon, D.; Chang, C.; Gaztañaga, E.; Hawken, A.; Jain, B.; Joachimi, B.; Vikram, V.; Abbott, T.; Allam, S.; Armstrong, R.; Benoit-Lévy, A.; Bernstein, G. M.; Bernstein, R. A.; Bertin, E.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Carrasco Kind, M.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Eifler, T. F.; Evrard, A. E.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Melchior, P.; Miquel, R.; Nord, B.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Sanchez, E.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Walker, A. R.

    2016-08-01

    It is well known that the probability distribution function (PDF) of galaxy density contrast is approximately lognormal; whether the PDF of mass fluctuations derived from weak lensing convergence (κWL) is lognormal is less well established. We derive PDFs of the galaxy and projected matter density distributions via the Counts in Cells (CiC) method. We use maps of galaxies and weak lensing convergence produced from the Dark Energy Survey (DES) Science Verification data over 139 deg2. We test whether the underlying density contrast is well described by a lognormal distribution for the galaxies, the convergence and their joint PDF. We confirm that the galaxy density contrast distribution is well modeled by a lognormal PDF convolved with Poisson noise at angular scales from 10'- 40'(corresponding to physical scales of 3-10 Mpc). We note that as κWL is a weighted sum of the mass fluctuations along the line of sight, its PDF is expected to be only approximately lognormal. We find that the κWL distribution is well modeled by a lognormal PDF convolved with Gaussian shape noise at scales between 10'and 20', with a best-fit χ2/DOF of 1.11 compared to 1.84 for a Gaussian model, corresponding to p-values 0.35 and 0.07 respectively, at a scale of 10'. Above 20'a simple Gaussian model is sufficient. The joint PDF is also reasonably fitted by a bivariate lognormal. As a consistency check we compare the variances derived from the lognormal modelling with those directly measured via CiC. Our methods are validated against maps from the MICE Grand Challenge N-body simulation.

  5. RCSLenS: testing gravitational physics through the cross-correlation of weak lensing and large-scale structure

    NASA Astrophysics Data System (ADS)

    Blake, Chris; Joudaki, Shahab; Heymans, Catherine; Choi, Ami; Erben, Thomas; Harnois-Deraps, Joachim; Hildebrandt, Hendrik; Joachimi, Benjamin; Nakajima, Reiko; van Waerbeke, Ludovic; Viola, Massimo

    2016-03-01

    The unknown nature of `dark energy' motivates continued cosmological tests of large-scale gravitational physics. We present a new consistency check based on the relative amplitude of non-relativistic galaxy peculiar motions, measured via redshift-space distortion, and the relativistic deflection of light by those same galaxies traced by galaxy-galaxy lensing. We take advantage of the latest generation of deep, overlapping imaging and spectroscopic data sets, combining the Red Cluster Sequence Lensing Survey, the Canada-France-Hawaii Telescope Lensing Survey, the WiggleZ Dark Energy Survey and the Baryon Oscillation Spectroscopic Survey. We quantify the results using the `gravitational slip' statistic EG, which we estimate as 0.48 ± 0.10 at z = 0.32 and 0.30 ± 0.07 at z = 0.57, the latter constituting the highest redshift at which this quantity has been determined. These measurements are consistent with the predictions of General Relativity, for a perturbed Friedmann-Robertson-Walker metric in a Universe dominated by a cosmological constant, which are EG = 0.41 and 0.36 at these respective redshifts. The combination of redshift-space distortion and gravitational lensing data from current and future galaxy surveys will offer increasingly stringent tests of fundamental cosmology.

  6. Test of relativistic gravity using microlensing of relativistically broadened lines in gravitationally lensed quasars

    NASA Astrophysics Data System (ADS)

    Neronov, A.; Vovk, Ie.

    2016-01-01

    We show that observation of the time-dependent effect of microlensing of relativistically broadened emission lines (such as e.g. the Fe K α line in x rays) in strongly lensed quasars could provide data on celestial mechanics of circular orbits in the direct vicinity of the horizon of supermassive black holes. This information can be extracted from the observation of evolution of the red/blue edge of the magnified line just before and just after the period of crossing of the innermost stable circular orbit by the microlensing caustic. The functional form of this evolution is insensitive to numerous astrophysical parameters of the accreting black hole and of the microlensing caustics network system (as opposed to the evolution of the full line spectrum). Measurement of the temporal evolution of the red/blue edge could provide a precision measurement of the radial dependence of the gravitational redshift and of velocity of the circular orbits, down to the innermost stable circular orbit. These measurements could be used to discriminate between general relativity and alternative models of the relativistic gravity in which the dynamics of photons and massive bodies orbiting the gravitating center is different from that of the geodesics in the Schwarzschild or Kerr space-times.

  7. The Orphan Lenses Project

    NASA Astrophysics Data System (ADS)

    Moustakas, Leonidas A.; Brownstein, J.; Fadely, R.; Fassnacht, C. D.; Gavazzi, R.; Goodsall, T.; Griffith, R. L.; Keeton, C. R.; Kneib, J. P.; Koekemoer, A.; Koopmans, L. V. E.; Marshall, P. J.; Merten, J.; Metcalf, R. B.; Oguri, M.; Papovich, C.; Rein, H.; Ryan, R.; Stewart, K. R.; Treu, T.

    2012-01-01

    Strong gravitational lenses are uniquely suited for the study of dark matter structure and substructure within massive halos of many scales, act as gravitational telescopes for distant faint objects, and can give powerful and competitive cosmological constraints. Some 300 lenses have been identified in the literature in one form or another; many others have been found, but perhaps have not warranted dedicated publications. The Orphan Lenses project aims to be a master compilation of all strong gravitational lenses that are known, and a community repository for candidate lenses. A clear and uniform database of basic properties and gravitational lens models is being developed, which will be available online and through a smartphone interactive application. I will present the project, and scientific highlights with this dataset.

  8. Discovery of a Strongly Lensed Massive Quiescent Galaxy at z = 2.636: Spatially Resolved Spectroscopy and Indications of Rotation

    NASA Astrophysics Data System (ADS)

    Newman, Andrew B.; Belli, Sirio; Ellis, Richard S.

    2015-11-01

    We report the discovery of RG1M0150, a massive, recently quenched galaxy at z = 2.636 that is multiply imaged by the cluster MACSJ0150.3-1005. We derive a stellar mass of {log}{M}*={11.49}-0.16+0.10 and a half-light radius of {R}e,{maj}=1.8+/- 0.4 {{kpc}}. Taking advantage of the lensing magnification, we are able to spatially resolve a remarkably massive yet compact quiescent galaxy at z\\gt 2 in ground-based near-infrared spectroscopic observations using Magellan/FIRE and Keck/MOSFIRE. We find no gradient in the strength of the Balmer absorption lines over 0.6{R}e-1.6{R}e, which are consistent with an age of 760 Myr. Gas emission in [N ii] broadly traces the spatial distribution of the stars and is coupled with weak Hα emission (log [N ii]/{{H}}α =0.6+/- 0.2), indicating that OB stars are not the primary ionizing source. The velocity dispersion within the effective radius is {σ }e,{stars}=271+/- 41 km s{}-1. We detect rotation in the stellar absorption lines for the first time beyond z∼ 1. Using a two-integral Jeans model that accounts for observational effects, we measure a dynamical mass of {log}{M}{{dyn}}=11.24+/- 0.14 and V/σ =0.70+/- 0.21. This is a high degree of rotation considering the modest observed ellipticity of 0.12 ± 0.08, but it is consistent with predictions from dissipational merger simulations that produce compact remnants. The mass of RG1M0150 implies that it is likely to become a slowly rotating elliptical. If it is typical, this suggests that the progenitors of massive ellipticals retain significant net angular momentum after quenching which later declines, perhaps through accretion of satellites.

  9. Strong-lensing analysis of MACS J0717.5+3745 from Hubble Frontier Fields observations: How well can the mass distribution be constrained?

    NASA Astrophysics Data System (ADS)

    Limousin, M.; Richard, J.; Jullo, E.; Jauzac, M.; Ebeling, H.; Bonamigo, M.; Alavi, A.; Clément, B.; Giocoli, C.; Kneib, J.-P.; Verdugo, T.; Natarajan, P.; Siana, B.; Atek, H.; Rexroth, M.

    2016-04-01

    We present a strong-lensing analysis of MACSJ0717.5+3745 (hereafter MACS J0717), based on the full depth of the Hubble Frontier Field (HFF) observations, which brings the number of multiply imaged systems to 61, ten of which have been spectroscopically confirmed. The total number of images comprised in these systems rises to 165, compared to 48 images in 16 systems before the HFF observations. Our analysis uses a parametric mass reconstruction technique, as implemented in the Lenstool software, and the subset of the 132 most secure multiple images to constrain a mass distribution composed of four large-scale mass components (spatially aligned with the four main light concentrations) and a multitude of galaxy-scale perturbers. We find a superposition of cored isothermal mass components to provide a good fit to the observational constraints, resulting in a very shallow mass distribution for the smooth (large-scale) component. Given the implications of such a flat mass profile, we investigate whether a model composed of "peaky" non-cored mass components can also reproduce the observational constraints. We find that such a non-cored mass model reproduces the observational constraints equally well, in the sense that both models give comparable total rms. Although the total (smooth dark matter component plus galaxy-scale perturbers) mass distributions of both models are consistent, as are the integrated two-dimensional mass profiles, we find that the smooth and the galaxy-scale components are very different. We conclude that, even in the HFF era, the generic degeneracy between smooth and galaxy-scale components is not broken, in particular in such a complex galaxy cluster. Consequently, insights into the mass distribution of MACS J0717 remain limited, emphasizing the need for additional probes beyond strong lensing. Our findings also have implications for estimates of the lensing magnification. We show that the amplification difference between the two models is larger

  10. Electron Lenses for Experiments on Nonlinear Dynamics with Wide Stable Tune Spreads in the Fermilab Integrable Optics Test Accelerator

    SciTech Connect

    Stancari, G.; Carlson, K.; McGee, M. W.; Nobrega, L. E.; Romanov, A. L.; Ruan, J.; Valishev, A.; Noll, D.

    2015-06-01

    Recent developments in the study of integrable Hamiltonian systems have led to nonlinear accelerator lattice designs with two transverse invariants. These lattices may drastically improve the performance of high-power machines, providing wide tune spreads and Landau damping to protect the beam from instabilities, while preserving dynamic aperture. To test the feasibility of these concepts, the Integrable Optics Test Accelerator (IOTA) is being designed and built at Fermilab. One way to obtain a nonlinear integrable lattice is by using the fields generated by a magnetically confined electron beam (electron lens) overlapping with the circulating beam. The parameters of the required device are similar to the ones of existing electron lenses. We present theory, numerical simulations, and first design studies of electron lenses for nonlinear integrable optics.

  11. The strong Bell inequalities: A proposed experimental test

    NASA Technical Reports Server (NTRS)

    Fry, Edward S.

    1994-01-01

    All previous experimental tests of Bell inequalities have required additional assumptions. The strong Bell inequalities (i.e. those requiring no additional assumptions) have never been tested. An experiment has been designed that can, for the first time, provide a definitive test of the strong Bell inequalities. Not only will the detector efficiency loophole be closed; but the locality condition will also be rigorously enforced. The experiment involves producing two Hg-199 atoms by a resonant Raman dissociation of a mercury dimer ((199)Hg2) that is in an electronic and nuclear spin singlet state. Bell inequalities can be tested by measuring angular momentum correlations between the spin one-half nuclei of the two Hg-199 atoms. The method used to make these latter measurements will be described.

  12. Mass reconstruction of galaxies clusters: Abell 2219, RXC J2248.7-4431, and SDSS J1004+4112 using strong gravitational lensing

    NASA Astrophysics Data System (ADS)

    Jaelani, Anton T.; Premadi, Premana W.

    2015-09-01

    This work presents mass reconstruction of galaxies cluster from strong lens analysis for Abell 2219 (z = 0.225), RXC J2248,7-4431 (z = 0.348), and SDSS J1004+4112 (z = 0.68) using parametric model sofware for strong gravitational lensing, glafic (Oguri 2010). We use assumptions of point source and source-plane approximation for minimization. We find that our parametric model well reproduces the positions of multiply imaged galaxies and quasars and time delays between quasar images. We find that the best-fit centroid of the dark halo (NFW) is quite consistent with the distribution of gas from observed X-ray. Radius enclosed mass profile and mass profile from hidrostatic assumption on distribution of gas from X-ray agree quite well with each other, including the radial slopes of the profiles with average discrepancies, Mlens/MX = 1.52 on the outer radius of images. Existence of dominant galaxy associate with compactness of cluster as lens. We find increasing of fraction of galaxies morphology from distribution of cluster members increase with redshift.

  13. Grating visual acuity testing as a means of psychophysical assessment of progressive addition lenses.

    PubMed

    Sullivan, C M; Fowler, C W

    1989-09-01

    Progressive addition lenses (PAL's) are subject to objectionable astigmatism due to the aspheric nature of their anterior surfaces. Optico-physical assessment of PAL's is commonly undertaken but these measures should be related to the psychophysical responses of patients whilst wearing PAL's. A technique previously used for the psychophysical assessment of contact lenses and spectacle lenses is adapted and demonstrated for the measurement of grating visual acuity (VA) through the aspheric portion of PAL's. The apparatus encompasses an astronomical telescope with magnifying power of unity designed to stabilize accommodation. This paper considers the astigmatism present with three different PAL designs along a horizontal section cutting orthogonally through the umbilical line of each lens. VA was measured, using high contrast vertical and horizontal gratings, along the same horizontal sections of the PAL's studied. A reduction in VA was noted with an increase in the angle of eccentricity from the umbilical line. PMID:2797709

  14. Complementarity of weak lensing and peculiar velocity measurements in testing general relativity

    SciTech Connect

    Song, Yong-Seon; Zhao Gongbo; Bacon, David; Koyama, Kazuya; Nichol, Robert C.; Pogosian, Levon

    2011-10-15

    We explore the complementarity of weak lensing and galaxy peculiar velocity measurements to better constrain modifications to General Relativity. We find no evidence for deviations from General Relativity on cosmological scales from a combination of peculiar velocity measurements (for Luminous Red Galaxies in the Sloan Digital Sky Survey) with weak lensing measurements (from the Canadian France Hawaii Telescope Legacy Survey). We provide a Fisher error forecast for a Euclid-like space-based survey including both lensing and peculiar velocity measurements and show that the expected constraints on modified gravity will be at least an order of magnitude better than with present data, i.e. we will obtain {approx_equal}5% errors on the modified gravity parametrization described here. We also present a model-independent method for constraining modified gravity parameters using tomographic peculiar velocity information, and apply this methodology to the present data set.

  15. Massive star clusters in a z=1 star-forming galaxy seen at a 100 pc scale thanks to strong gravitational lensing

    NASA Astrophysics Data System (ADS)

    Dessauges-Zavadsky, Miroslava; Cava, Antonio; Richard, Johan; Schaerer, Daniel; Egami, Eiichi

    2015-08-01

    Deep and high-resolution imaging has revealed clumpy, rest-frame UV morphologies among z=1-3 galaxies. The majority of these galaxies has been shown to be dominated by ordered disk rotation, which led to the conclusion that the observed giant clumps, resolved on kpc-scales, are generated from disk fragmentation due to gravitational instability. State-of-the-art numerical simulations show that they may occupy a relevant role in galaxy evolution, contributing to the galactic bulge formation. Despite the high resolution attained by the most advanced ground- and space-based facilities, as well as in numerical simulations, the intrinsic typical masses and scale sizes of these star-forming clumps remain unconstrained, since they are barely resolved at z=1-3.Thanks to the amplification and stretching power provided by strong gravitational lensing, we are likely to reach the spatial resolving power for unveiling the physics of these star-forming regions. We report on the study of clumpy star formation observed in the Cosmic Snake, a strongly lensed galaxy at z=1, representative of the typical star-forming population close to the peak of Universe activity. About 20 clumps are identified in the HST images. Benefiting from extreme amplification factors up to 100, they are resolved down to an intrinsic scale of 100 pc, never reached before at z=1.The HST multi-wavelength analysis of these individual star clusters allows us to determine their intrinsic physical properties, showing stellar masses (Ms) from 106 to 108.3 Msun, sizes from 100 to 400 pc, and ages from 106 to 108.5 yr. The masses we find are in line with the new, very high resolution numerical simulations, which also suggest that the massive giant clumps previously observed at high redshift with Ms as high as 109-10 Msun may suffer from low resolution effects, being unresolved conglomerates of less massive star clusters. We also compare our results with those of massive young clusters in nearby galaxies. Our approved

  16. 30 CFR 18.30 - Windows and lenses.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed...

  17. 30 CFR 18.30 - Windows and lenses.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed...

  18. 30 CFR 18.30 - Windows and lenses.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed...

  19. 30 CFR 18.30 - Windows and lenses.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed...

  20. 30 CFR 18.30 - Windows and lenses.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Windows and lenses. 18.30 Section 18.30 Mineral... § 18.30 Windows and lenses. (a) MSHA may waive testing of materials for windows or lenses except headlight lenses. When tested, material for windows or lenses shall meet the test requirements prescribed...

  1. Strong lensing by a node of the cosmic web. The core of MACS J0717.5+3745 at z = 0.55

    NASA Astrophysics Data System (ADS)

    Limousin, M.; Ebeling, H.; Richard, J.; Swinbank, A. M.; Smith, G. P.; Jauzac, M.; Rodionov, S.; Ma, C.-J.; Smail, I.; Edge, A. C.; Jullo, E.; Kneib, J.-P.

    2012-08-01

    We present results of a strong-lensing analysis of MACS J0717.5+3745 (hereafter MACS J0717), an extremely X-ray luminous galaxy cluster at z = 0.55. Observations at different wavelengths reveal a complex and dynamically very active cluster, whose core is connected to a large scale filament extended over several Mpc. Using multi-passband imaging data obtained with the Hubble Space Telescope's Advanced Camera for Surveys (ACS), we identify 15 multiply imaged systems across the full field of view of ACS, five of which we confirmed spectroscopically in ground-based follow-up observations with the Keck telescope. We use these multiply imaged systems to constrain a parametric model of the mass distribution in the cluster core, employing a new parallelized version of the Lenstool software. The main result is that the most probable description of the mass distribution comprises four cluster-scale dark matter haloes. The total mass distribution follows the light distribution but strongly deviates from the distribution of the intra-cluster gas as traced by the X-ray surface brightness. This confirms the complex morphology proposed by previous studies. We interpret this segregation of collisional and collisionless matter as strong evidence of multiple mergers and ongoing dynamical activity. MACS J0717 thus constitutes one of the most disturbed clusters presently known and, featuring a projected mass within the ACS field of view (R = 150″ = 960 kpc) of 2.11 ± 0.23 × 1015 M⊙, the system is also one of the most massive known. Based on observations obtained with the Hubble Space Telescope (HST) and the Keck Telescope.

  2. The Sloan Bright Arcs Survey : Discovery of Seven New Strongly Lensed Galaxies from $\\rm{z}=0.66-2.94$

    SciTech Connect

    Kubo, Jeffrey M.; Allam, Sahar S.; Annis, James; Buckley-Geer, Elizabeth J.; Diehl, H.Thomas; Drabek, Emily; Frieman, Joshua A.; Hao, Jiangang; Kubik, Donna; Lin, Huan; Soares-Santos, Marcelle

    2010-10-01

    We report the discovery of seven new, very bright gravitational lens systems from our ongoing gravitational lens search, the Sloan Bright Arcs Survey (SBAS). Two of the systems are confirmed to have high source redshifts z = 2.19 and z = 2.94. Three other systems lie at intermediate redshift with z = 1.33, 1.82, 1.93 and two systems are at low redshift z = 0.66, 0.86. The lensed source galaxies in all of these systems are bright, with i-band magnitudes ranging from 19.73-22.06. We present the spectrum of each of the source galaxies in these systems along with estimates of the Einstein radius for each system. The foreground lens in most systems is identified by a red sequence based cluster finder as a galaxy group; one system is identified as a moderately rich cluster. In total the SBAS has now discovered nineteen strong lens systems in the SDSS imaging data, eight of which are among the highest surface brightness z {approx_equal} 2-3 galaxies known.

  3. Testing the strong equivalence principle by radio ranging

    NASA Technical Reports Server (NTRS)

    Canuto, V. M.; Goldman, I.; Shapiro, I. I.

    1984-01-01

    Planetary range data offer the most promising means to test the validity of the Strong Equivalence Principle (SEP). Analytical expressions for the perturbation in the 'range' expected from an SEP violation predicted by the 'variation-of-G' method and by the 'two-times' approach are derived and compared. The dominant term in both expressions is quadratic in time. Analysis of existing range data should allow a determination of the coefficient of this term with a one-standard-deviation uncertainty of about 1 part in 100 billion/yr.

  4. TESTING THE UNIVERSALITY OF THE FUNDAMENTAL METALLICITY RELATION AT HIGH REDSHIFT USING LOW-MASS GRAVITATIONALLY LENSED GALAXIES

    SciTech Connect

    Belli, Sirio; Ellis, Richard S.; Jones, Tucker; Richard, Johan

    2013-08-01

    We present rest-frame optical spectra for a sample of nine low-mass star-forming galaxies in the redshift range 1.5 < z < 3 which are gravitationally lensed by foreground clusters. We used Triplespec, an echelle spectrograph at the Palomar 200 inch telescope that is very effective for this purpose as it samples the entire near-infrared spectrum simultaneously. By measuring the flux of nebular emission lines, we derive gas-phase metallicities and star formation rates, and by fitting the optical to infrared spectral energy distributions we obtain stellar masses. Taking advantage of the high magnification due to strong lensing, we are able to probe the physical properties of galaxies with stellar masses in the range 7.8 < log M/M{sub Sun} < 9.4 whose star formation rates are similar to those of typical star-forming galaxies in the local universe. We compare our results with the locally determined relation between stellar mass, gas metallicity, and star formation rate. Our data are in excellent agreement with this relation, with an average offset ({Delta}log (O/H)) = 0.01 {+-} 0.08, suggesting a universal relationship. Remarkably, the scatter around the fundamental metallicity relation is only 0.24 dex, smaller than that observed locally at the same stellar masses, which may provide an important additional constraint for galaxy evolution models.

  5. Types of Contact Lenses

    MedlinePlus

    ... Consumer Devices Consumer Products Contact Lenses Types of Contact Lenses Share Tweet Linkedin Pin it More sharing ... Orthokeratology (Ortho-K) Decorative (Plano) Contact Lenses Soft Contact Lenses Soft contact lenses are made of soft, ...

  6. [C II] and {sup 12}CO(1-0) emission maps in HLSJ091828.6+514223: A strongly lensed interacting system at z = 5.24

    SciTech Connect

    Rawle, T. D.; Altieri, B.; Egami, E.; Rex, M.; Clement, B.; Bussmann, R. S.; Gurwell, M.; Fazio, G. G.; Ivison, R. J.; Boone, F.; Combes, F.; Danielson, A. L. R.; Smail, I.; Swinbank, A. M.; Edge, A. C.; Richard, J.; Blain, A. W.; Dessauges-Zavadsky, M.; Jones, T.; Kneib, J.-P.; and others

    2014-03-01

    We present Submillimeter Array [C II] 158 μm and Karl G. Jansky Very Large Array {sup 12}CO(1-0) line emission maps for the bright, lensed, submillimeter source at z = 5.2430 behind A 773: HLSJ091828.6+514223 (HLS0918). We combine these measurements with previously reported line profiles, including multiple {sup 12}CO rotational transitions, [C I], water, and [N II], providing some of the best constraints on the properties of the interstellar medium in a galaxy at z > 5. HLS0918 has a total far-infrared (FIR) luminosity L {sub FIR(8–1000} {sub μm)} = (1.6 ± 0.1) × 10{sup 14} L {sub ☉} μ{sup –1}, where the total magnification μ{sub total} = 8.9 ± 1.9, via a new lens model from the [C II] and continuum maps. Despite a HyLIRG luminosity, the FIR continuum shape resembles that of a local LIRG. We simultaneously fit all of the observed spectral line profiles, finding four components that correspond cleanly to discrete spatial structures identified in the maps. The two most redshifted spectral components occupy the nucleus of a massive galaxy, with a source-plane separation <1 kpc. The reddest dominates the continuum map (demagnified L {sub FIR,} {sub component} = (1.1 ± 0.2) × 10{sup 13} L {sub ☉}) and excites strong water emission in both nuclear components via a powerful FIR radiation field from the intense star formation. A third star-forming component is most likely a region of a merging companion (ΔV ∼ 500 km s{sup –1}) exhibiting generally similar gas properties. The bluest component originates from a spatially distinct region and photodissociation region analysis suggests that it is lower density, cooler, and forming stars less vigorously than the other components. Strikingly, it has very strong [N II] emission, which may suggest an ionized, molecular outflow. This comprehensive view of gas properties and morphology in HLS0918 previews the science possible for a large sample of high-redshift galaxies once ALMA attains full sensitivity.

  7. The Systematic Error Test for PSF Correction in Weak Gravitational Lensing Shear Measurement By the ERA Method By Idealizing PSF

    NASA Astrophysics Data System (ADS)

    Okura, Yuki; Futamase, Toshifumi

    2016-08-01

    We improve the ellipticity of re-smeared artificial image (ERA) method of point-spread function (PSF) correction in a weak lensing shear analysis in order to treat the realistic shape of galaxies and the PSF. This is done by re-smearing the PSF and the observed galaxy image using a re-smearing function (RSF) and allows us to use a new PSF with a simple shape and to correct the PSF effect without any approximations or assumptions. We perform a numerical test to show that the method applied for galaxies and PSF with some complicated shapes can correct the PSF effect with a systematic error of less than 0.1%. We also apply the ERA method for real data of the Abell 1689 cluster to confirm that it is able to detect the systematic weak lensing shear pattern. The ERA method requires less than 0.1 or 1 s to correct the PSF for each object in a numerical test and a real data analysis, respectively.

  8. Kernel regression estimates of time delays between gravitationally lensed fluxes

    NASA Astrophysics Data System (ADS)

    AL Otaibi, Sultanah; Tiňo, Peter; Cuevas-Tello, Juan C.; Mandel, Ilya; Raychaudhury, Somak

    2016-06-01

    Strongly lensed variable quasars can serve as precise cosmological probes, provided that time delays between the image fluxes can be accurately measured. A number of methods have been proposed to address this problem. In this paper, we explore in detail a new approach based on kernel regression estimates, which is able to estimate a single time delay given several data sets for the same quasar. We develop realistic artificial data sets in order to carry out controlled experiments to test the performance of this new approach. We also test our method on real data from strongly lensed quasar Q0957+561 and compare our estimates against existing results.

  9. Development and testing of new biologically-based polymers as advanced biocompatible contact lenses

    SciTech Connect

    Bertozzi, Carolyn R.

    2000-06-01

    Nature has evolved complex and elegant materials well suited to fulfill a myriad of functions. Lubricants, structural scaffolds and protective sheaths can all be found in nature, and these provide a rich source of inspiration for the rational design of materials for biomedical applications. Many biological materials are based in some fashion on hydrogels, the crosslinked polymers that absorb and hold water. Biological hydrogels contribute to processes as diverse as mineral nucleation during bone growth and protection and hydration of the cell surface. The carbohydrate layer that coats all living cells, often referred to as the glycocalyx, has hydrogel-like properties that keep cell surfaces well hydrated, segregated from neighboring cells, and resistant to non-specific protein deposition. With the molecular details of cell surface carbohydrates now in hand, adaptation of these structural motifs to synthetic materials is an appealing strategy for improving biocompatibility. The goal of this collaborative project between Prof. Bertozzi's research group, the Center for Advanced Materials at Lawrence Berkeley National Laboratory and Sunsoft Corporation was the design, synthesis and characterization of novel hydrogel polymers for improved soft contact lens materials. Our efforts were motivated by the urgent need for improved materials that allow extended wear, and essential feature for those whose occupation requires the use of contact lenses rather than traditional spectacles. Our strategy was to transplant the chemical features of cell surface molecules into contact lens materials so that they more closely resemble the tissue in which they reside. Specifically, we integrated carbohydrate molecules similar to those found on cell surfaces, and sulfoxide materials inspired by the properties of the carbohydrates, into hydrogels composed of biocompatible and manufacturable substrates. The new materials were characterized with respect to surface and bulk hydrophilicity, and

  10. CMB lensing and primordial squeezed non-gaussianity

    SciTech Connect

    Pearson, Ruth; Lewis, Antony; Regan, Donough E-mail: antony@cosmologist.info

    2012-03-01

    Squeezed primordial non-Gaussianity can strongly constrain early-universe physics, but it can only be observed on the CMB after it has been gravitationally lensed. We give a new simple non-perturbative prescription for accurately calculating the effect of lensing on any squeezed primordial bispectrum shape, and test it with simulations. We give the generalization to polarization bispectra, and discuss the effect of lensing on the trispectrum. We explain why neglecting the lensing smoothing effect does not significantly bias estimators of local primordial non-Gaussianity, even though the change in shape can be ∼>10%. We also show how τ{sub NL} trispectrum estimators can be well approximated by much simpler CMB temperature modulation estimators, and hence that there is potentially a ∼ 10–30% bias due to very large-scale lensing modes, depending on the range of modulation scales included. Including dipole sky modulations can halve the τ{sub NL} error bar if kinematic effects can be subtracted using known properties of the CMB temperature dipole. Lensing effects on the g{sub NL} trispectrum are small compared to the error bar. In appendices we give the general result for lensing of any primordial bispectrum, and show how any full-sky squeezed bispectrum can be decomposed into orthogonal modes of distinct angular dependence.

  11. Weak Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Pires, Sandrine; Starck, Jean-Luc; Leonard, Adrienne; Réfrégier, Alexandre

    2012-03-01

    , which affects the evolution of structures. Gravitational lensing is the process by which light from distant galaxies is bent by the gravity of intervening mass in the Universe as it travels toward us. This bending causes the images of background galaxies to appear slightly distorted, and can be used to extract important cosmological information. In the beginning of the twentieth century, A. Einstein predicted that massive bodies could be seen as gravitational lenses that bend the path of light rays by creating a local curvature in space time. One of the first confirmations of Einstein's new theory was the observation during the 1919 solar eclipse of the deflection of light from distant stars by the sun. Since then, a wide range of lensing phenomena have been detected. The gravitational deflection of light by mass concentrations along light paths produces magnification, multiplication, and distortion of images. These lensing effects are illustrated by Figure 14.2, which shows one of the strongest lenses observed: Abell 2218, a very massive and distant cluster of galaxies in the constellation Draco. The observed gravitational arcs are actually the magnified and strongly distorted images of galaxies that are about 10 times more distant than the cluster itself. These strong gravitational lensing effects are very impressive but they are very rare. Far more prevalent are weak gravitational lensing effects, which we consider in this chapter, and in which the induced distortion in galaxy images is much weaker. These gravitational lensing effects are now widely used, but the amplitude of the weak lensing signal is so weak that its detection relies on the accuracy of the techniques used to analyze the data. Future weak lensing surveys are already planned in order to cover a large fraction of the sky with high accuracy, such as Euclid [68]. However, improving accuracy also places greater demands on the methods used to extract the available information.

  12. H II Region Metallicity Constraints Near the Site of the Strongly Lensed Supernova “SN Refsdal” at Redshift 1.49

    NASA Astrophysics Data System (ADS)

    Yuan, Tiantian; Kobayashi, Chiaki; Kewley, Lisa J.

    2015-05-01

    We present the local H ii region metallicity near the site of the recently discovered multiply lensed supernova (SN; “SN Refsdal”) at redshift 1.49. “SN Refsdal” is located at the outer spiral arm (˜7 kpc) of the lensed host galaxy, which we previously reported to exhibit a steep negative galactocentric metallicity gradient. Based on our updated near-infrared integral field spectroscopic data, the gas-phase metallicity averaged in an intrinsic radius of ˜550 pc surrounding an H ii region ˜200 pc away from the SN site is 12 + log(O/H)PP04N2≤slant 8.67. The metallicity averaged over nine H ii regions at similar galactocentric distances (˜5-7 kpc) as “SN Refsdal” is constrained to be 12 + log(O/H)PP04N2≤slant 8.11. Given the fortuitous discovery of “SN Refsdal” in an advantageously lensed face-on spiral, this is the first observational constraint on the local metallicity environment of an SN site at redshift z\\gt 1.

  13. Can Palomar Transient Factory Survey Data Be Used to Confirm Gravitationally Lensed Quasar Candidates?

    NASA Astrophysics Data System (ADS)

    Spitzer, Isaac; Quimby, Robert

    2016-01-01

    Strongly lensed quasars can be used to study the Hubble constant and the lens mass by measuring time delay and image separation. These objects can require years of data to confirm however, so using data from preexisting surveys could greatly reduce the amount of time required to study them. We attempt to use Palomar Transient Factory survey data to detect variability in strongly lensed quasars and to measure time delays between the quasar images. We test our procedure using known gravitationally lensed quasars with measured time delays.

  14. Testing metallicity indicators at z ˜ 1.4 with the gravitationally lensed galaxy CASSOWARY 20

    NASA Astrophysics Data System (ADS)

    James, Bethan L.; Pettini, Max; Christensen, Lise; Auger, Matthew W.; Becker, George D.; King, Lindsay J.; Quider, Anna M.; Shapley, Alice E.; Steidel, Charles C.

    2014-05-01

    We present X-shooter observations of CASSOWARY 20 (CSWA 20), a star-forming (SFR ˜ 6 M⊙ yr-1) galaxy at z = 1.433, magnified by a factor of 11.5 by the gravitational lensing produced by a massive foreground galaxy at z = 0.741. We analysed the integrated physical properties of the H II regions of CSWA 20 using temperature- and density-sensitive emission lines. We find the abundance of oxygen to be ˜1/7 of solar, while carbon is ˜50 times less abundant than in the Sun. The unusually low C/O ratio may be an indication of a particularly rapid time-scale of chemical enrichment. The wide wavelength coverage of X-shooter gives us access to five different methods for determining the metallicity of CSWA 20, three based on emission lines from H II regions and two on absorption features formed in the atmospheres of massive stars. All five estimates are in agreement, within the factor of ˜2 uncertainty of each method. The interstellar medium (ISM) of CSWA 20 only partially covers the star-forming region as viewed from our direction; in particular, absorption lines from neutrals and first ions are exceptionally weak. We find evidence for large-scale outflows of the ISM with speeds of up 750 km s-1, similar to the values measured in other high-z galaxies sustaining much higher rates of star formation.

  15. Development of an In Vitro Ocular Platform to Test Contact Lenses.

    PubMed

    Phan, Chau-Minh; Walther, Hendrik; Gao, Huayi; Rossy, Jordan; Subbaraman, Lakshman N; Jones, Lyndon

    2016-01-01

    Currently, in vitro evaluations of contact lenses (CLs) for drug delivery are typically performed in large volume vials,(1-6) which fail to mimic physiological tear volumes.(7) The traditional model also lacks the natural tear flow component and the blinking reflex, both of which are defining factors of the ocular environment. The development of a novel model is described in this study, which consists of a unique 2-piece design, eyeball and eyelid piece, capable of mimicking physiological tear volume. The models are created from 3-D printed molds (Polytetrafluoroethylene or Teflon molds), which can be used to generate eye models from various polymers, such as polydimethylsiloxane (PDMS) and agar. Further modifications to the eye pieces, such as the integration of an explanted human or animal cornea or human corneal construct, will permit for more complex in vitro ocular studies. A commercial microfluidic syringe pump is integrated with the platform to emulate physiological tear secretion. Air exposure and mechanical wear are achieved using two mechanical actuators, of which one moves the eyelid piece laterally, and the other moves the eyeballeyepiece circularly. The model has been used to evaluate CLs for drug delivery and deposition of tear components on CLs. PMID:27078088

  16. Pulsar lensing geometry

    NASA Astrophysics Data System (ADS)

    Liu, Siqi; Pen, Ue-Li; Macquart, J.-P.; Brisken, Walter; Deller, Adam

    2016-05-01

    We test the inclined sheet pulsar scintillation model (Pen & Levin) against archival very long baseline interferometry (VLBI) data on PSR 0834+06 and show that its scintillation properties can be precisely reproduced by a model in which refraction occurs on two distinct lens planes. These data strongly favour a model in which grazing-incidence refraction instead of diffraction off turbulent structures is the primary source of pulsar scattering. This model can reproduce the parameters of the observed diffractive scintillation with an accuracy at the percent level. Comparison with new VLBI proper motion results in a direct measure of the ionized interstellar medium (ISM) screen transverse velocity. The results are consistent with ISM velocities local to the PSR 0834+06 sight-line (through the Galaxy). The simple 1-D structure of the lenses opens up the possibility of using interstellar lenses as precision probes for pulsar lens mapping, precision transverse motions in the ISM, and new opportunities for removing scattering to improve pulsar timing. We describe the parameters and observables of this double screen system. While relative screen distances can in principle be accurately determined, a global conformal distance degeneracy exists that allows a rescaling of the absolute distance scale. For PSR B0834+06, we present VLBI astrometry results that provide (for the first time) a direct measurement of the distance of the pulsar. For most of the recycled millisecond pulsars that are the targets of precision timing observations, the targets where independent distance measurements are not available. The degeneracy presented in the lens modelling could be broken if the pulsar resides in a binary system.

  17. Numerical tests of AdS/CFT at strong coupling

    SciTech Connect

    Berenstein, David; Cotta, Randel; Leonardi, Rodrigo

    2008-07-15

    We study various correlation functions (two- and three-point functions) in a large N matrix model of six commuting matrices with a numerical Monte Carlo algorithm. This is equivalent to a model of a gas of particles in six dimensions with a confining quadratic potential and logarithmic repulsions at finite temperature, where we are measuring the leading-order nongaussianities in the thermal fluctuations. This is a simplified model of the low-energy dynamics of N=4 SYM at strong coupling. We find strong evidence that the simplified matrix model matches with the dual gravitational description of three-point functions in the AdS/CFT correspondence.

  18. Testing a phenomenologically extended DGP model with upcoming weak lensing surveys

    SciTech Connect

    Camera, Stefano; Diaferio, Antonaldo; Cardone, Vincenzo F. E-mail: diaferio@ph.unito.it

    2011-01-01

    A phenomenological extension of the well-known brane-world cosmology of Dvali, Gabadadze and Porrati (eDGP) has recently been proposed. In this model, a cosmological-constant-like term is explicitly present as a non-vanishing tension σ on the brane, and an extra parameter α tunes the cross-over scale r{sub c}, the scale at which higher dimensional gravity effects become non negligible. Since the Hubble parameter in this cosmology reproduces the same ΛCDM expansion history, we study how upcoming weak lensing surveys, such as Euclid and DES (Dark Energy Survey), can confirm or rule out this class of models. We perform Monte Carlo Markov Chain simulations to determine the parameters of the model, using Type Ia Supernovæ, H(z) data, Gamma Ray Bursts and Baryon Acoustic Oscillations. We also fit the power spectrum of the temperature anisotropies of the Cosmic Microwave Background to obtain the correct normalisation for the density perturbation power spectrum. Then, we compute the matter and the cosmic shear power spectra, both in the linear and non-linear régimes. The latter is calculated with the two different approaches of Hu and Sawicki (2007) (HS) and Khoury and Wyman (2009) (KW). With the eDGP parameters coming from the Markov Chains, KW reproduces the ΛCDM matter power spectrum at both linear and non-linear scales and the ΛCDM and eDGP shear signals are degenerate. This result does not hold with the HS prescription. Indeed, Euclid can distinguish the eDGP model from ΛCDM because their expected power spectra roughly differ by the 3σ uncertainty in the angular scale range 700∼

  19. Lensing duct

    DOEpatents

    Beach, R.J.; Benett, W.J.

    1994-04-26

    A lensing duct to condense (intensify) light using a combination of front surface lensing and reflective waveguiding is described. The duct tapers down from a wide input side to a narrow output side, with the input side being lens-shaped and coated with an antireflective coating for more efficient transmission into the duct. The four side surfaces are uncoated, preventing light from escaping by total internal reflection as it travels along the duct (reflective waveguiding). The duct has various applications for intensifying light, such as in the coupling of diode array pump light to solid state lasing materials, and can be fabricated from inexpensive glass and plastic. 3 figures.

  20. Lensing duct

    DOEpatents

    Beach, Raymond J. , Benett

    1994-01-01

    A lensing duct to condense (intensify) light using a combination of front surface lensing and reflective waveguiding. The duct tapers down from a wide input side to a narrow output side, with the input side being lens-shaped and coated with an antireflective coating for more efficient transmission into the duct. The four side surfaces are uncoated, preventing light from escaping by total internal reflection as it travels along the duct (reflective waveguiding). The duct has various applications for intensifying light, such as in the coupling of diode array pump light to solid state lasing materials, and can be fabricated from inexpensive glass and plastic.

  1. SPT 0538–50: Physical conditions in the interstellar medium of a strongly lensed dusty star-forming galaxy at z = 2.8

    SciTech Connect

    Bothwell, M. S.; Aguirre, J. E.; Chapman, S. C.; Marrone, D. P.; Vieira, J. D.; Bock, J. J.; Downes, T. P.; Ashby, M. L. N.; Aravena, M.; De Breuck, C.; Gullberg, B.; Benson, B. A.; Carlstrom, J. E.; Crawford, T. M.; Bradford, C. M.; Brodwin, M.; Fassnacht, C. D.; Gonzalez, A. H.; Greve, T. R.; Hezaveh, Y.; and others

    2013-12-10

    We present observations of SPT-S J053816–5030.8, a gravitationally lensed dusty star-forming galaxy (DSFG) at z = 2.7817 that was first discovered at millimeter wavelengths by the South Pole Telescope. SPT 0538–50 is typical of the brightest sources found by wide-field millimeter-wavelength surveys, being lensed by an intervening galaxy at moderate redshift (in this instance, at z = 0.441). We present a wide array of multi-wavelength spectroscopic and photometric data on SPT 0538–50, including data from ALMA, Herschel PACS and SPIRE, Hubble, Spitzer, the Very Large Telescope, ATCA, APEX, and the Submillimeter Array. We use high-resolution imaging from the Hubble Space Telescope to de-blend SPT 0538–50, separating DSFG emission from that of the foreground lens. Combined with a source model derived from ALMA imaging (which suggests a magnification factor of 21 ± 4), we derive the intrinsic properties of SPT 0538–50, including the stellar mass, far-IR luminosity, star formation rate, molecular gas mass, and—using molecular line fluxes—the excitation conditions within the interstellar medium. The derived physical properties argue that we are witnessing compact, merger-driven star formation in SPT 0538–50 similar to local starburst galaxies and unlike that seen in some other DSFGs at this epoch.

  2. Aerosol lenses propagation model.

    PubMed

    Tremblay, Grégoire; Roy, Gilles

    2011-09-01

    We propose a model based on the properties of cascading lenses modulation transfer function (MTF) to reproduce the irradiance of a screen illuminated through a dense aerosol cloud. In this model, the aerosol cloud is broken into multiple thin layers considered as individual lenses. The screen irradiance generated by these individual layers is equivalent to the point-spread function (PSF) of each aerosol lens. Taking the Fourier transform of the PSF as a MTF, we cascade the lenses MTF to find the cloud MTF. The screen irradiance is found with the Fourier transform of this MTF. We show the derivation of the model and we compare the results with the Undique Monte Carlo simulator for four aerosols at three optical depths. The model is in agreement with the Monte Carlo for all the cases tested. PMID:21886230

  3. Strong Iron Emission in Quasars: Testing a Thermal Model.

    NASA Astrophysics Data System (ADS)

    Cooper, Erin M.; Leighly, K.

    2012-01-01

    FeII emission poses a long-standing yet important problem in studies of quasar broad emission lines. FeII emission is a primary coolant of the broad-line region, a primary player in the set of emission line correlations known as Eigenvector 1, and it can yield information about metallicity in the early Universe. It is generally thought that UV FeII emission has the same shape in all quasars, varying only in equivalent width; however, Leighly et al. 2007 identified two characteristic shapes. Typical quasars exhibit FeII emission in the 2200-2600Å region. PHL 1811-like quasars exhibit additional FeII emission in the 2200-2600Å region and excess emission in the regions 2100-2200Å and 1950-2050Å. Leighly et al. hypothesized the difference in shape arises from differences in Fe excitation and ionization in these strong Fe emitters: the emission in typical spectra arises from low-excitation FeII, and in PHL 1811-like spectra the emission arises from additional high-excitation FeII and FeIII. We investigate the near-UV Fe emission in quasars by modeling strong iron emitters with templates generated using the atomic data in the Kurucz database. By grouping lines of similar upper energy level, we populate the levels according to the Boltzmann factor, as in a thermal gas. A preliminary fit of the strong iron emitter SDSS J124244.37+624659.1 shows the expected lower-excitation levels dominating the FeII emission. Analysis of the PHL 1811 spectrum shows the expected higher-excitation levels contributing to the FeII emission, and additional FeIII flux relative to the SDSS J124244.37+624659.1 spectrum. More analysis is needed to interpret the spectrum in the 2000-2300Å range, where the excess of flux presents a challenge to model. Additional results will include a larger sample of strong Fe emitting quasars of both types. This work is funded by NSF AST-0707703.

  4. A test of the flavor independence of strong interactions

    SciTech Connect

    Hildreth, M.D.

    1994-08-01

    The authors present a comparison of the strong couplings of b, c, and light (u, d, and s) quarks derived from multi-jet rates in flavor-tagged samples of hadronic Z{sup 0} decays recorded with the SLC Large Detector at the SLAC Linear Collider. By comparing the rates of 3-jet events in these three samples they have extracted (Preliminary) values of: {alpha}{sub s}(uds)/{alpha}{sub s}(all) = 0.96 {+-} 0.03(stat.) {+-} 0.04(syst.) {+-} 0.02(theory), {alpha}{sub s}(c)/{alpha}{sub s}(all) = 1.16 {+-} 0.11(stat.) {+-} 0.10(syst.) {+-} 0.07(theory), {alpha}{sub s}(b)/{alpha}{sub s}(all) = 0.98 {+-} 0.04(stat.) {+-} 0.08(syst.) {+-} 0.02(theory).

  5. Test of the flavor independence of strong interactions

    NASA Astrophysics Data System (ADS)

    Abe, K.; Abt, I.; Ahn, C. J.; Akagi, T.; Allen, N. J.; Ash, W. W.; Aston, D.; Bacchetta, N.; Baird, K. G.; Baltay, C.; Band, H. R.; Barakat, M. B.; Baranko, G.; Bardon, O.; Barklow, T.; Bazarko, A. O.; Ben-David, R.; Benvenuti, A. C.; Bienz, T.; Bilei, G. M.; Bisello, D.; Blaylock, G.; Bogart, J. R.; Bolton, T.; Bower, G. R.; Brau, J. E.; Breidenbach, M.; Bugg, W. M.; Burke, D.; Burnett, T. H.; Burrows, P. N.; Busza, W.; Calcaterra, A.; Caldwell, D. O.; Calloway, D.; Camanzi, B.; Carpinelli, M.; Cassell, R.; Castaldi, R.; Castro, A.; Cavalli-Sforza, M.; Church, E.; Cohn, H. O.; Coller, J. A.; Cook, V.; Cotton, R.; Cowan, R. F.; Coyne, D. G.; D'oliveira, A.; Damerell, C. J.; de Sangro, R.; de Simone, P.; dell'orso, R.; Dima, M.; Du, P. Y.; Dubois, R.; Eisenstein, B. I.; Elia, R.; Falciai, D.; Fan, C.; Fero, M. J.; Frey, R.; Furuno, K.; Gillman, T.; Gladding, G.; Gonzalez, S.; Hallewell, G. D.; Hart, E. L.; Hasegawa, Y.; Hedges, S.; Hertzbach, S. S.; Hildreth, M. D.; Huber, J.; Huffer, M. E.; Hughes, E. W.; Hwang, H.; Iwasaki, Y.; Jacques, P.; Jaros, J.; Johnson, A. S.; Johnson, J. R.; Johnson, R. A.; Junk, T.; Kajikawa, R.; Kalelkar, M.; Karliner, I.; Kawahara, H.; Kendall, H. W.; King, M. E.; King, R.; Kofler, R. R.; Krishna, N. M.; Kroeger, R. S.; Labs, J. F.; Langston, M.; Lath, A.; Lauber, J. A.; Leith, D. W.; Liu, X.; Loreti, M.; Lu, A.; Lynch, H. L.; Ma, J.; Mancinelli, G.; Manly, S.; Mantovani, G.; Markiewicz, T. W.; Maruyama, T.; Massetti, R.; Masuda, H.; Mazzucato, E.; McKemey, A. K.; Meadows, B. T.; Messner, R.; Mockett, P. M.; Moffeit, K. C.; Mours, B.; Müller, G.; Muller, D.; Nagamine, T.; Nauenberg, U.; Neal, H.; Nussbaum, M.; Ohnishi, Y.; Osborne, L. S.; Panvini, R. S.; Park, H.; Pavel, T. J.; Peruzzi, I.; Pescara, L.; Piccolo, M.; Piemontese, L.; Pieroni, E.; Pitts, K. T.; Plano, R. J.; Prepost, R.; Prescott, C. Y.; Punkar, G. D.; Quigley, J.; Ratcliff, B. N.; Reeves, T. W.; Rensing, P. E.; Rochester, L. S.; Rothberg, J. E.; Rowson, P. C.; Russell, J. J.; Saxton, O. H.; Schalk, T.; Schindler, R. H.; Schneekloth, U.; Schumm, B. A.; Seiden, A.; Sen, S.; Serbo, V. V.; Shaevitz, M. H.; Shank, J. T.; Shapiro, G.; Shapiro, S. L.; Sherden, D. J.; Simopoulos, C.; Sinev, N. B.; Smith, S. R.; Snyder, J. A.; Stamer, P.; Steiner, H.; Steiner, R.; Strauss, M. G.; Su, D.; Suekane, F.; Sugiyama, A.; Suzuki, S.; Swartz, M.; Szumilo, A.; Takahashi, T.; Taylor, F. E.; Torrence, E.; Turk, J. D.; Usher, T.; Va'vra, J.; Vannini, C.; Vella, E.; Venuti, J. P.; Verdier, R.; Verdini, P. G.; Wagner, S. R.; Waite, A. P.; Watts, S. J.; Weidemann, A. W.; Whitaker, J. S.; White, S. L.; Wickens, F. J.; Williams, D. A.; Williams, D. C.; Williams, S. H.; Willocq, S.; Wilson, R. J.; Wisniewski, W. J.; Woods, M.; Word, G. B.; Wyss, J.; Yamamoto, R. K.; Yamartino, J. M.; Yang, X.; Yellin, S. J.; Young, C. C.; Yuta, H.; Zapalac, G.; Zdarko, R. W.; Zeitlin, C.; Zhang, Z.; Zhou, J.

    1996-03-01

    We present a comparison of the strong couplings of light (u, d, and s), c, and b quarks determined from multijet rates in flavor-tagged samples of hadronic Z0 decays recorded with the SLC Large Detector at the SLAC Linear Collider. Flavor separation on the basis of lifetime and decay multiplicity differences among hadrons containing light, c, and b quarks was made using the SLD precision tracking system. We find αudss/αalls=0.987+/-0.027(stat)+/-0.022(sy t)+/-0.022(theory), αcs/αalls=1.012+/-0.104+/-0.102+/-0.096, and αbs/αalls=1.026+/-0.041+/-0.041+/-0.030.

  6. Improved test of the flavor independence of strong interactions

    NASA Astrophysics Data System (ADS)

    Abe, K.; Abe, K.; Abe, T.; Adam, I.; Akagi, T.; Allen, N. J.; Arodzero, A.; Ash, W. W.; Aston, D.; Baird, K. G.; Baltay, C.; Band, H. R.; Barakat, M. B.; Bardon, O.; Barklow, T. L.; Bauer, J. M.; Bellodi, G.; Ben-David, R.; Benvenuti, A. C.; Bilei, G. M.; Bisello, D.; Blaylock, G.; Bogart, J. R.; Bolen, B.; Bower, G. R.; Brau, J. E.; Breidenbach, M.; Bugg, W. M.; Burke, D.; Burnett, T. H.; Burrows, P. N.; Calcaterra, A.; Caldwell, D. O.; Calloway, D.; Camanzi, B.; Carpinelli, M.; Cassell, R.; Castaldi, R.; Castro, A.; Cavalli-Sforza, M.; Chou, A.; Church, E.; Cohn, H. O.; Coller, J. A.; Convery, M. R.; Cook, V.; Cotton, R.; Cowan, R. F.; Coyne, D. G.; Crawford, G.; Damerell, C. J.; Danielson, M. N.; Daoudi, M.; de Groot, N.; dell'orso, R.; Dervan, P. J.; de Sangro, R.; Dima, M.; D'oliveira, A.; Dong, D. N.; Du, P. Y.; Dubois, R.; Eisenstein, B. I.; Eschenburg, V.; Etzion, E.; Fahey, S.; Falciai, D.; Fan, C.; Fernandez, J. P.; Fero, M. J.; Flood, K.; Frey, R.; Gillman, T.; Gladding, G.; Gonzalez, S.; Hart, E. L.; Harton, J. L.; Hasan, A.; Hasuko, K.; Hedges, S. J.; Hertzbach, S. S.; Hildreth, M. D.; Huber, J.; Huffer, M. E.; Hughes, E. W.; Huynh, X.; Hwang, H.; Iwasaki, M.; Jackson, D. J.; Jacques, P.; Jaros, J. A.; Jiang, Z. Y.; Johnson, A. S.; Johnson, J. R.; Johnson, R. A.; Junk, T.; Kajikawa, R.; Kalelkar, M.; Kamyshkov, Y.; Kang, H. J.; Karliner, L.; Kawahara, H.; Kim, Y. D.; King, R.; King, M. E.; Kofler, R. R.; Krishna, N. M.; Kroeger, R. S.; Langston, M.; Lath, A.; Leith, D. W.; Lia, V.; Lin, C.-J. S.; Liu, X.; Liu, M. X.; Loreti, M.; Lu, A.; Lynch, H. L.; Ma, J.; Mancinelli, G.; Manly, S.; Mantovani, G.; Markiewicz, T. W.; Maruyama, T.; Masuda, H.; Mazzucato, E.; McKemey, A. K.; Meadows, B. T.; Menegatti, G.; Messner, R.; Mockett, P. M.; Moffeit, K. C.; Moore, T. B.; Morii, M.; Muller, D.; Murzin, V.; Nagamine, T.; Narita, S.; Nauenberg, U.; Neal, H.; Nussbaum, M.; Oishi, N.; Onoprienko, D.; Osborne, L. S.; Panvini, R. S.; Park, H.; Park, C. H.; Pavel, T. J.; Peruzzi, I.; Piccolo, M.; Piemontese, L.; Pieroni, E.; Pitts, K. T.; Plano, R. J.; Prepost, R.; Prescott, C. Y.; Punkar, G. D.; Quigley, J.; Ratcliff, B. N.; Reeves, T. W.; Reidy, J.; Reinertsen, P. L.; Rensing, P. E.; Rochester, L. S.; Rowson, P. C.; Russell, J. J.; Saxton, O. H.; Schalk, T.; Schindler, R. H.; Schumm, B. A.; Schwiening, J.; Sen, S.; Serbo, V. V.; Shaevitz, M. H.; Shank, J. T.; Shapiro, G.; Sherden, D. J.; Shmakov, K. D.; Simopoulos, C.; Sinev, N. B.; Smith, S. R.; Smy, M. B.; Snyder, J. A.; Staengle, H.; Stahl, A.; Stamer, P.; Steiner, R.; Steiner, H.; Strauss, M. G.; Su, D.; Suekane, F.; Sugiyama, A.; Suzuki, S.; Swartz, M.; Szumilo, A.; Takahashi, T.; Taylor, F. E.; Thom, J.; Torrence, E.; Toumbas, N. K.; Trandafir, A. I.; Turk, J. D.; Usher, T.; Vannini, C.; Va'vra, J.; Vella, E.; Venuti, J. P.; Verdier, R.; Verdini, P. G.; Wagner, S. R.; Wagner, D. L.; Waite, A. P.; Walston, S.; Wang, J.; Ward, C.; Watts, S. J.; Weidemann, A. W.; Weiss, E. R.; Whitaker, J. S.; White, S. L.; Wickens, F. J.; Williams, B.; Williams, D. C.; Williams, S. H.; Willocq, S.; Wilson, R. J.; Wisniewski, W. J.; Wittlin, J. L.; Woods, M.; Word, G. B.; Wright, T. R.; Wyss, J.; Yamamoto, R. K.; Yamartino, J. M.; Yang, X.; Yashima, J.; Yellin, S. J.; Young, C. C.; Yuta, H.; Zapalac, G.; Zdarko, R. W.; Zhou, J.

    1999-01-01

    We present an improved comparison of the strong coupling of the gluon to light (ql=u+d+s), c, and b quarks, determined from multijet rates in flavor-tagged samples of hadronic Z0 decays recorded with the SLC Large Detector at the SLAC Linear Collider between 1993 and 1995. Flavor separation among primary qlq¯l, cc¯, and bb¯ final states was made on the basis of the reconstructed mass of long-lived heavy-hadron decay vertices, yielding tags with high purity and low bias against >= 3-jet final states. We find: αcs/αudss=1.036+/-0.043(stat)+0.041-0.045(syst)+0.020-0.018(theory) and αbs/αudss=1.004+/-0.018(stat)+0.026-0.031(syst)+0.018-0.029(theory).

  7. Contrast sensitivity test and conventional and high frequency audiometry: information beyond that required to prescribe lenses and headsets

    NASA Astrophysics Data System (ADS)

    Comastri, S. A.; Martin, G.; Simon, J. M.; Angarano, C.; Dominguez, S.; Luzzi, F.; Lanusse, M.; Ranieri, M. V.; Boccio, C. M.

    2008-04-01

    In Optometry and in Audiology, the routine tests to prescribe correction lenses and headsets are respectively the visual acuity test (the first chart with letters was developed by Snellen in 1862) and conventional pure tone audiometry (the first audiometer with electrical current was devised by Hartmann in 1878). At present there are psychophysical non invasive tests that, besides evaluating visual and auditory performance globally and even in cases catalogued as normal according to routine tests, supply early information regarding diseases such as diabetes, hypertension, renal failure, cardiovascular problems, etc. Concerning Optometry, one of these tests is the achromatic luminance contrast sensitivity test (introduced by Schade in 1956). Concerning Audiology, one of these tests is high frequency pure tone audiometry (introduced a few decades ago) which yields information relative to pathologies affecting the basal cochlea and complements data resulting from conventional audiometry. These utilities of the contrast sensitivity test and of pure tone audiometry derive from the facts that Fourier components constitute the basis to synthesize stimuli present at the entrance of the visual and auditory systems; that these systems responses depend on frequencies and that the patient's psychophysical state affects frequency processing. The frequency of interest in the former test is the effective spatial frequency (inverse of the angle subtended at the eye by a cycle of a sinusoidal grating and measured in cycles/degree) and, in the latter, the temporal frequency (measured in cycles/sec). Both tests have similar duration and consist in determining the patient's threshold (corresponding to the inverse multiplicative of the contrast or to the inverse additive of the sound intensity level) for each harmonic stimulus present at the system entrance (sinusoidal grating or pure tone sound). In this article the frequencies, standard normality curves and abnormal threshold shifts

  8. Strong Loophole-Free Test of Local Realism.

    PubMed

    Shalm, Lynden K; Meyer-Scott, Evan; Christensen, Bradley G; Bierhorst, Peter; Wayne, Michael A; Stevens, Martin J; Gerrits, Thomas; Glancy, Scott; Hamel, Deny R; Allman, Michael S; Coakley, Kevin J; Dyer, Shellee D; Hodge, Carson; Lita, Adriana E; Verma, Varun B; Lambrocco, Camilla; Tortorici, Edward; Migdall, Alan L; Zhang, Yanbao; Kumor, Daniel R; Farr, William H; Marsili, Francesco; Shaw, Matthew D; Stern, Jeffrey A; Abellán, Carlos; Amaya, Waldimar; Pruneri, Valerio; Jennewein, Thomas; Mitchell, Morgan W; Kwiat, Paul G; Bienfang, Joshua C; Mirin, Richard P; Knill, Emanuel; Nam, Sae Woo

    2015-12-18

    We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high-speed polarization measurements. A high-quality polarization-entangled source of photons, combined with high-efficiency, low-noise, single-photon detectors, allows us to make measurements without requiring any fair-sampling assumptions. Using a hypothesis test, we compute p values as small as 5.9×10^{-9} for our Bell violation while maintaining the spacelike separation of our events. We estimate the degree to which a local realistic system could predict our measurement choices. Accounting for this predictability, our smallest adjusted p value is 2.3×10^{-7}. We therefore reject the hypothesis that local realism governs our experiment. PMID:26722906

  9. Anomaly distribution of quasar magnitudes: a test of lensing by a hypothetic supergiant molecular cloud in the Galactic halo

    NASA Astrophysics Data System (ADS)

    Giraud, E.

    2012-07-01

    Context. An anomaly in the distribution of quasar magnitudes based on the Sloan Digital Sky survey, was reported by Longo. The angular size of this quasar anomaly is on the order of ±15° on the sky. A smooth low surface brightness structure detected in γ-rays and at 408 MHz, coincides with the sky location and extent of the anomaly, and is close to the northern component of a pair of γ-ray bubbles discovered in the Fermi Gamma-ray Space Telescope survey. Molecular clouds are thought to be illuminated by cosmic rays. Molecular gas in the Galaxy, in the form of cold H2, may be a significant component of dark matter as suggested by Pfenniger et al. Aims: I test the hypothesis that the magnitude anomaly in the quasar distribution, is due to lensing by a hypothetical supergiant molecular cloud (SGMC) either in or falling into the Galactic halo. Methods: A series of grid lens models are built by assuming that a SGMC is a fractal structure constructed with clumps of 10-3 M⊙, 10 AU in size, and considering various fractal dimensions. Local amplifications are computed by using the single-plane approximation. Results: A complex network of caustics due to the clumpy structure is present. Our best single plane lens model capable of explaining Longo's effect, at least in sparse regions, requires a mass (1.5-4.1) × 1010 M⊙ within 8.7 × 8.7 × (5-8.6) kpc3 at a lens plane distance of 20 kpc, and is constructed from a molecular-cloud building-block of 5 × 105 M⊙ within a scale of 30 pc expanded by fractal scaling with dimension D = 1.8-2 out to 5-8.6 kpc for the SGMC. The mass budget depends on the cloud depth and on the fractal dimension. Conclusions: If such a SGMC were found to exist, it may provide at least part of a lensing explanation for the luminous anomaly discovered in quasars and red galaxies.

  10. Lotung large-scale seismic test strong motion records

    SciTech Connect

    Not Available

    1992-03-01

    The Electric Power Research Institute (EPRI), in cooperation with the Taiwan Power Company (TPC), constructed two models (1/4 scale and 1/12 scale) of a nuclear plant concrete containment structure at a seismically active site in Lotung, Taiwan. Extensive instrumentation was deployed to record both structural and ground responses during earthquakes. The experiment, generally referred to as the Lotung Large-Scale Seismic Test (LSST), was used to gather data for soil-structure interaction (SSI) analysis method evaluation and validation as well as for site ground response investigation. A number of earthquakes having local magnitudes ranging from 4.5 to 7.0 have been recorded at the LSST site since the completion of the test facility in September 1985. This report documents the earthquake data, both raw and processed, collected from the LSST experiment. Volume 1 of the report provides general information on site location, instrument types and layout, data acquisition and processing, and data file organization. The recorded data are described chronologically in subsequent volumes of the report.

  11. Weak Lensing with LSST

    NASA Astrophysics Data System (ADS)

    Wittman, David M.; Jain, B.; Jarvis, M.; Knox, L.; Margoniner, V.; Takada, M.; Tyson, J.; Zhan, H.; LSST Weak Lensing Science Collaboration

    2006-12-01

    Constraining dark energy parameters with weak lensing is one of the primary science goals of the LSST. The LSST Weak Lensing Science Collaboration has been formed with the goal of optimizing the weak lensing science by optimizing the survey cadence; working with Data Management to insure high-quality pipeline processing which will meet our needs; developing the necessary analysis tools well before the onset of data-taking; participating in high-fidelity simulations to test the system end-to-end; and analyzing the real dataset as it becomes available. We review the major weak lensing probes, the twoand three-point shear correlations, and how they constrain dark energy parameters. We also review the possibility of going beyond dark energy models and testing gravity with the LSST data. To realize the promise of the awesome LSST statistical precision, we must ensure that systematic errors are kept under control. We review the major sources of systematics and our plans for mitigation. We present data that demonstrate that these sources of systematics can be kept to a level smaller than the statistical error.

  12. Gravitational Lensing

    SciTech Connect

    Lincoln, Don

    2015-06-24

    In a long line of intellectual triumphs, Einstein’s theory of general relativity was his greatest and most imaginative. It tells us that what we experience as gravity can be most accurately described as the bending of space itself. This idea leads to consequences, including gravitational lensing, which is caused by light traveling in this curved space. This is works in a way analogous to a lens (and hence the name). In this video, Fermilab’s Dr. Don Lincoln explains a little general relativity, a little gravitational lensing, and tells us how this phenomenon allows us to map out the matter of the entire universe, including the otherwise-invisible dark matter.

  13. 3D printed diffractive terahertz lenses.

    PubMed

    Furlan, Walter D; Ferrando, Vicente; Monsoriu, Juan A; Zagrajek, Przemysław; Czerwińska, Elżbieta; Szustakowski, Mieczysław

    2016-04-15

    A 3D printer was used to realize custom-made diffractive THz lenses. After testing several materials, phase binary lenses with periodic and aperiodic radial profiles were designed and constructed in polyamide material to work at 0.625 THz. The nonconventional focusing properties of such lenses were assessed by computing and measuring their axial point spread function (PSF). Our results demonstrate that inexpensive 3D printed THz diffractive lenses can be reliably used in focusing and imaging THz systems. Diffractive THz lenses with unprecedented features, such as extended depth of focus or bifocalization, have been demonstrated. PMID:27082335

  14. Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Saha, P.; Murdin, P.

    2000-11-01

    Gravity bends light rays in a way analogous to, but quantitatively different from, the way it bends trajectories of passing particles. If light from some bright object passes close enough to some foreground mass, that object's image will be altered. The effect is more like a piece of bathroom glass in the sky than a precision-ground and well-focused lens, but the terms `gravitational lensing' or ...

  15. Interference testing methods of large astronomical mirrors base on lenses and CGH wavefront correctors

    NASA Astrophysics Data System (ADS)

    Abdulkadyrov, Magomed A.; Belousov, Sergey P.; Patrikeev, Vladimir E.; Semenov, Alexandr P.

    2010-07-01

    Since last years and at present days LZOS, JSC has been producing a range of primary mirrors of astronomical telescopes with diameter more than 1m under contracts with foreign companies. Simultaneous testing of an aspherical surface figure by means of a lens corrector and CGH (computer generated hologram) corrector, testing of the corrector using the CGH allow challenging the task of definite testing of the mirrors surfaces figure. The results of successful figuring of the mirrors with diameter up to 4m like VISTA Project (Southern European Observatory), TNT (Thai National telescope, Australia - Thailand), LCO telescopes (Las Cumbres Observatory, USA; Russian national projects and meeting these mirrors specifications' requirements are all considered as the sufficient evidence.

  16. Characterization of acoustic lenses with the Foucault test by confocal laser scanning microscopy

    NASA Astrophysics Data System (ADS)

    Ahmed Mohamed, E. T.; Abdelrahman, A.; Pluta, M.; Grill, W.

    2010-03-01

    In this work, the Foucault knife-edge test, which has traditionally been known as the classic test for optical imaging devices, is used to characterize an acoustic lens for operation at 1.2 GHz. A confocal laser scanning microscope (CLSM) was used as the illumination and detection device utilizing its pinhole instead of the classical knife edge that is normally employed in the Foucault test. Information about the geometrical characteristics, such as the half opening angle of the acoustic lens, were determined as well as the quality of the calotte of the lens used for focusing. The smallest focal spot size that could be achieved with the examined lens employed as a spherical reflector was found to be about 1 μm. By comparison to the idealized resolution a degradation of about a factor of 2 can be deduced. This limits the actual quality of the acoustic focus.

  17. Gravitational lensing by black holes: The case of Sgr A*

    SciTech Connect

    Bozza, V.

    2014-01-14

    The strong gravitational fields created by black holes dramatically affect the propagation of photons by bending their trajectories. Gravitational lensing thus stands as the main source of information on the space-time structure in such extreme regimes. We will review the theory and phenomenology of gravitational lensing by black holes, with the generation of higher order images and giant caustics by rotating black holes. We will then focus on Sgr A*, the black hole at the center of the Milky Way, for which next-to-come technology will be able to reach resolutions of the order of the Schwarzschild radius and ultimately test the existence of an event horizon.

  18. Phakic Intraocular Lenses

    MedlinePlus

    ... Implants and Prosthetics Phakic Intraocular Lenses Phakic Intraocular Lenses Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Phakic intraocular lenses are new devices used to correct nearsightedness. These ...

  19. Habitual wearers of colored lenses adapt more rapidly to the color changes the lenses produce.

    PubMed

    Engel, Stephen A; Wilkins, Arnold J; Mand, Shivraj; Helwig, Nathaniel E; Allen, Peter M

    2016-08-01

    The visual system continuously adapts to the environment, allowing it to perform optimally in a changing visual world. One large change occurs every time one takes off or puts on a pair of spectacles. It would be advantageous for the visual system to learn to adapt particularly rapidly to such large, commonly occurring events, but whether it can do so remains unknown. Here, we tested whether people who routinely wear spectacles with colored lenses increase how rapidly they adapt to the color shifts their lenses produce. Adaptation to a global color shift causes the appearance of a test color to change. We measured changes in the color that appeared "unique yellow", that is neither reddish nor greenish, as subjects donned and removed their spectacles. Nine habitual wearers and nine age-matched control subjects judged the color of a small monochromatic test light presented with a large, uniform, whitish surround every 5s. Red lenses shifted unique yellow to more reddish colors (longer wavelengths), and greenish lenses shifted it to more greenish colors (shorter wavelengths), consistent with adaptation "normalizing" the appearance of the world. In controls, the time course of this adaptation contained a large, rapid component and a smaller gradual one, in agreement with prior results. Critically, in habitual wearers the rapid component was significantly larger, and the gradual component significantly smaller than in controls. The total amount of adaptation was also larger in habitual wearers than in controls. These data suggest strongly that the visual system adapts with increasing rapidity and strength as environments are encountered repeatedly over time. An additional unexpected finding was that baseline unique yellow shifted in a direction opposite to that produced by the habitually worn lenses. Overall, our results represent one of the first formal reports that adjusting to putting on or taking off spectacles becomes easier over time, and may have important

  20. Tolerances in panoramic lenses

    NASA Astrophysics Data System (ADS)

    Thibault, Simon; Dallaire, Xavier

    2014-09-01

    Almost every aspect concerning the optical design of panoramic lenses brings new challenges to optical designers. Examples of these include ray tracing programs having problems finding the entrance pupil which is moving through the field-of-view, optimization, production particularities due to the shape of the lenses, and ways of tolerancing these systems having strong distortion. This last topic will be discussed in this paper. We will start from a historical perspective on the understanding of panoramic imagery. This will lead us to the modern panoramic imager called the Panomorph lens. We will discuss the particular case of the tolerance of the front surface (most of the time a freeform surface) and the impact on the image quality, both image footprint and field curvature. We will explain the behavior using first and second order approaches.

  1. Exploring the Dark and Dusty Universe with Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Elíasdóttir, Árdís

    2007-12-01

    2218. However, the second large scale dark matter clump is found to be larger and with a flatter core than previous models have found. This flatness is further supported by "blind tests" which do not place galaxy sized components near its centre. An analysis of the cluster galaxies in velocity space finds evidence for two substructures corresponding to the two large scale dark matter halos. The X-ray data and the distribution in velocity space are found to support the interpretation that the bimodal mass distribution arises from a cluster merger. It is also shown that strong lensing constraints can reliably detect substructure,dark or luminous, if the substructure is massive or locally perturbs a system. Finally, the thesis closes with a short discussion on two smaller projects related to lens modelling. The first is the concentration of the mass distribution in the galaxy cluster Abell 1689, which is found to be marginally higher than values expected from numerical simulations. The second is the possible lensing of the gamma ray burst GRB 050509B. This gamma ray burst is associated both with an elliptical galaxy and with a galaxy cluster, which could be foreground objects lensing the burst. It is shown, assuming that the gamma ray burst is a backgrounds ource, that it is most likely only weakly affected by lensing.

  2. Gravitational lensing in quasar samples

    NASA Astrophysics Data System (ADS)

    Claeskens, Jean-François; Surdej, Jean

    The first cosmic mirage was discovered approximately 20 years ago as the double optical counterpart of a radio source. This phenomenon had been predicted some 70 years earlier as a consequence of General Relativity. We present here a summary of what we have learnt since. The applications are so numerous that we had to concentrate on a few selected aspects of this new field of research. This review is focused on strong gravitational lensing, i.e. the formation of multiple images, in QSO samples. It is intended to give the reader an up-to-date status of the observations and to present an overview of its most interesting potential applications in cosmology and astrophysics, as well as numerous important results achieved so far. The first section follows an intuitive approach to the basics of gravitational lensing and is developed in view of our interest in multiply imaged quasars. The astrophysical and cosmological applications of gravitational lensing are outlined in Sect. 2 and the most important results are presented in Sect. 5. Sections 3 and 4 are devoted to the observations. Finally, conclusions are summarized in the last section. We have tried to avoid duplication with existing (and excellent) introductions to the field of gravitational lensing. For this reason, we did not concentrate on the individual properties of specific lens models, as these are already well presented in Narayan and Bartelmann (1996) and on a more intuitive ground in Refsdal and Surdej (1994). Wambsganss (1998) proposes a broad view on gravitational lensing in astronomy; the reviews by Fort and Mellier (1994) and Hattori et al. (1999) deal with lensing by galaxy clusters; microlensing in the Galaxy and the local group is reviewed by Paczynski (1996) and a general panorama on weak lensing is given by Bartelmann and Schneider (1999) and Mellier (1999). The monograph on the theory of gravitational lensing by Schneider, Ehlers and Falco (1992) also remains a reference in the field.

  3. KINOFORM LENSES - TOWARD NANOMETER RESOLUTION.

    SciTech Connect

    STEIN, A.; EVANS-LUTTERODT, K.; TAYLOR, A.

    2004-10-23

    While hard x-rays have wavelengths in the nanometer and sub-nanometer range, the ability to focus them is limited by the quality of sources and optics, and not by the wavelength. A few options, including reflective (mirrors), diffractive (zone plates) and refractive (CRL's) are available, each with their own limitations. Here we present our work with kinoform lenses which are refractive lenses with all material causing redundant 2{pi} phase shifts removed to reduce the absorption problems inherently limiting the resolution of refractive lenses. By stacking kinoform lenses together, the effective numerical aperture, and thus the focusing resolution, can be increased. The present status of kinoform lens fabrication and testing at Brookhaven is presented as well as future plans toward achieving nanometer resolution.

  4. Gravitational lenses

    SciTech Connect

    Turner, E.L.

    1988-07-01

    For several years astronomers have devoted considerable effort to finding and studying a class of celestial phenomena whose very existence depends on rare cosmic accidents. These are gravitational-lens events, which occur when two or more objects at different distances from the earth happen to lie along the same line of sight and so coincide in the sky. The radiation from the more distant object, typically a quasar, is bent by the gravitational field of the foreground object. The bending creates a cosmic mirage: distorted or multiple images of the background object. Such phenomena may reveal many otherwise undetectable features of the image source, of the foreground object and of the space lying between them. Such observations could help to resolve several fundamental questions in cosmology. In the past decade theoretical and observational research on gravitational lenses has grown rapidly and steadily. At this writing at least 17 candidate lens systems have been discussed in the literature. Of the 17 lens candidates reported so far in professional literature, only five are considered to have been reliably established by subsequent observations. Another three are generally regarded as weak or speculative cases with less than 50 percent chance of actually being lens systems. In the remaining nine cases the evidence is mixed or is sparse enough so that the final judgment could swing either way. As might be concluded, little of the scientific promise of gravitational lenses has yet been realized. The work has not yielded a clear value for the proportionality constant or any of the other fundamental cosmological parameter. 7 figs.

  5. Glasses and Contact Lenses

    MedlinePlus

    ... Here's Help White House Lunch Recipes Glasses and Contact Lenses KidsHealth > For Kids > Glasses and Contact Lenses Print A A A Text Size What's ... together the way they should. But eyeglasses or contact lenses, also called corrective lenses, can help most ...

  6. Galaxy cluster lensing masses in modified lensing potentials

    DOE PAGESBeta

    Barreira, Alexandre; Li, Baojiu; Jennings, Elise; Merten, Julian; King, Lindsay; Baugh, Carlton M.; Pascoli, Silvia

    2015-10-28

    In this study, we determine the concentration–mass relation of 19 X-ray selected galaxy clusters from the Cluster Lensing and Supernova Survey with Hubble survey in theories of gravity that directly modify the lensing potential. We model the clusters as Navarro–Frenk–White haloes and fit their lensing signal, in the Cubic Galileon and Nonlocal gravity models, to the lensing convergence profiles of the clusters. We discuss a number of important issues that need to be taken into account, associated with the use of non-parametric and parametric lensing methods, as well as assumptions about the background cosmology. Our results show that the concentrationmore » and mass estimates in the modified gravity models are, within the error bars, the same as in Λ cold dark matter. This result demonstrates that, for the Nonlocal model, the modifications to gravity are too weak at the cluster redshifts, and for the Galileon model, the screening mechanism is very efficient inside the cluster radius. However, at distances ~ [2–20] Mpc/h from the cluster centre, we find that the surrounding force profiles are enhanced by ~ 20–40% in the Cubic Galileon model. This has an impact on dynamical mass estimates, which means that tests of gravity based on comparisons between lensing and dynamical masses can also be applied to the Cubic Galileon model.« less

  7. Galaxy cluster lensing masses in modified lensing potentials

    SciTech Connect

    Barreira, Alexandre; Li, Baojiu; Jennings, Elise; Merten, Julian; King, Lindsay; Baugh, Carlton M.; Pascoli, Silvia

    2015-10-28

    In this study, we determine the concentration–mass relation of 19 X-ray selected galaxy clusters from the Cluster Lensing and Supernova Survey with Hubble survey in theories of gravity that directly modify the lensing potential. We model the clusters as Navarro–Frenk–White haloes and fit their lensing signal, in the Cubic Galileon and Nonlocal gravity models, to the lensing convergence profiles of the clusters. We discuss a number of important issues that need to be taken into account, associated with the use of non-parametric and parametric lensing methods, as well as assumptions about the background cosmology. Our results show that the concentration and mass estimates in the modified gravity models are, within the error bars, the same as in Λ cold dark matter. This result demonstrates that, for the Nonlocal model, the modifications to gravity are too weak at the cluster redshifts, and for the Galileon model, the screening mechanism is very efficient inside the cluster radius. However, at distances ~ [2–20] Mpc/h from the cluster centre, we find that the surrounding force profiles are enhanced by ~ 20–40% in the Cubic Galileon model. This has an impact on dynamical mass estimates, which means that tests of gravity based on comparisons between lensing and dynamical masses can also be applied to the Cubic Galileon model.

  8. Galaxy cluster lensing masses in modified lensing potentials

    NASA Astrophysics Data System (ADS)

    Barreira, Alexandre; Li, Baojiu; Jennings, Elise; Merten, Julian; King, Lindsay; Baugh, Carlton M.; Pascoli, Silvia

    2015-12-01

    We determine the concentration-mass relation of 19 X-ray selected galaxy clusters from the Cluster Lensing and Supernova Survey with Hubble survey in theories of gravity that directly modify the lensing potential. We model the clusters as Navarro-Frenk-White haloes and fit their lensing signal, in the Cubic Galileon and Nonlocal gravity models, to the lensing convergence profiles of the clusters. We discuss a number of important issues that need to be taken into account, associated with the use of non-parametric and parametric lensing methods, as well as assumptions about the background cosmology. Our results show that the concentration and mass estimates in the modified gravity models are, within the error bars, the same as in Λ cold dark matter. This result demonstrates that, for the Nonlocal model, the modifications to gravity are too weak at the cluster redshifts, and for the Galileon model, the screening mechanism is very efficient inside the cluster radius. However, at distances ˜(2-20) Mpc h-1 from the cluster centre, we find that the surrounding force profiles are enhanced by ˜20-40 per cent in the Cubic Galileon model. This has an impact on dynamical mass estimates, which means that tests of gravity based on comparisons between lensing and dynamical masses can also be applied to the Cubic Galileon model.

  9. Learning unit: Thin lenses

    NASA Astrophysics Data System (ADS)

    Nita, L.-S.

    2012-04-01

    Learning unit: Thin lenses "Why objects seen through lenses are sometimes upright and sometimes reversed" Nita Laura Simona National College of Arts and Crafts "Constantin Brancusi", Craiova, Romania 1. GEOMETRIC OPTICS. 13 hours Introduction (models, axioms, principles, conventions) 1. Thin lenses (Types of lenses. Defining elements. Path of light rays through lenses. Image formation. Required physical quantities. Lens formulas). 2. Lens systems (Non-collated lenses. Focalless systems). 3. Human eye (Functioning as an optical system. Sight defects and their corrections). 4. Optical instruments (Characteristics exemplified by a magnifying glass. Paths of light rays through a simplified photo camera. Path of light rays through a classical microscope) (Physics curriculum for the IXth grade/ 2011). This scenario exposes a learning unit based on experimental sequences (defining specific competencies), as a succession of lessons started by noticing a problem whose solution assumes the setup of an experiment under laboratory conditions. Progressive learning of theme objectives are realised with sequential experimental steps. The central cognitive process is the induction or the generalization (development of new knowledge based on observation of examples or counterexamples of the concept to be learnt). Pupil interest in theme objectives is triggered by problem-situations, for example: "In order to better see small objects I need a magnifying glass. But when using a magnifier, small object images are sometimes seen upright and sometimes seen reversed!" Along the way, pupils' reasoning will converge to the idea: "The image of an object through a lens depends on the relative distances among object, lens, and observer". Associated learning model: EXPERIMENT Specific competencies: derived from the experiment model, in agreement with the following learning unit steps I. Evoking - Anticipation: Size of the problem, formulation of hypotheses and planning of experiment. II

  10. The M31 pixel lensing plan campaign: MACHO lensing and self-lensing signals

    SciTech Connect

    Calchi Novati, S.; Scarpetta, G.; Bozza, V.; Bruni, I.; Gualandi, R.; Dall'Ora, M.; De Paolis, F.; Ingrosso, G.; Nucita, A.; Strafella, F.; Dominik, M.; Jetzer, Ph.; Mancini, L.; Safonova, M.; Subramaniam, A.; Sereno, M.; Gould, A.; Collaboration: PLAN Collaboration

    2014-03-10

    We present the final analysis of the observational campaign carried out by the PLAN (Pixel Lensing Andromeda) collaboration to detect a dark matter signal in form of MACHOs through the microlensing effect. The campaign consists of about 1 month/year observations carried out over 4 years (2007-2010) at the 1.5 m Cassini telescope in Loiano (Astronomical Observatory of BOLOGNA, OAB) plus 10 days of data taken in 2010 at the 2 m Himalayan Chandra Telescope monitoring the central part of M31 (two fields of about 13' × 12.'6). We establish a fully automated pipeline for the search and the characterization of microlensing flux variations. As a result, we detect three microlensing candidates. We evaluate the expected signal through a full Monte Carlo simulation of the experiment completed by an analysis of the detection efficiency of our pipeline. We consider both 'self lensing' and 'MACHO lensing' lens populations, given by M31 stars and dark matter halo MACHOs, in M31 and the Milky Way, respectively. The total number of events is consistent with the expected self-lensing rate. Specifically, we evaluate an expected signal of about two self-lensing events. As for MACHO lensing, for full 0.5(10{sup –2}) M {sub ☉} MACHO halos, our prediction is for about four (seven) events. The comparatively small number of expected MACHO versus self-lensing events, together with the small number statistics at our disposal, do not enable us to put strong constraints on that population. Rather, the hypothesis, suggested by a previous analysis, on the MACHO nature of OAB-07-N2, one of the microlensing candidates, translates into a sizeable lower limit for the halo mass fraction in form of the would-be MACHO population, f, of about 15% for 0.5 M {sub ☉} MACHOs.

  11. Spitzer UltRa Faint SUrvey Program (SURFS UP). II. IRAC-detected Lyman-Break Galaxies at 6 ≲ z ≲ 10 behind Strong-lensing Clusters

    NASA Astrophysics Data System (ADS)

    Huang, Kuang-Han; Bradač, Maruša; Lemaux, Brian C.; Ryan, R. E., Jr.; Hoag, Austin; Castellano, Marco; Amorín, Ricardo; Fontana, Adriano; Brammer, Gabriel B.; Cain, Benjamin; Lubin, L. M.; Merlin, Emiliano; Schmidt, Kasper B.; Schrabback, Tim; Treu, Tommaso; Gonzalez, Anthony H.; von der Linden, Anja; Knight, Robert I.

    2016-01-01

    We study the stellar population properties of the IRAC-detected 6 ≲ z ≲ 10 galaxy candidates from the Spitzer UltRa Faint SUrvey Program. Using the Lyman Break selection technique, we find a total of 17 galaxy candidates at 6 ≲ z ≲ 10 from Hubble Space Telescope images (including the full-depth images from the Hubble Frontier Fields program for MACS 1149 and MACS 0717) that have detections at signal-to-noise ratios ≥ 3 in at least one of the IRAC 3.6 and 4.5 μm channels. According to the best mass models available for the surveyed galaxy clusters, these IRAC-detected galaxy candidates are magnified by factors of ˜1.2-5.5. Due to the magnification of the foreground galaxy clusters, the rest-frame UV absolute magnitudes M1600 are between -21.2 and -18.9 mag, while their intrinsic stellar masses are between 2 × 108M⊙ and 2.9 × 109M⊙. We identify two Lyα emitters in our sample from the Keck DEIMOS spectra, one at zLyα = 6.76 (in RXJ 1347) and one at zLyα = 6.32 (in MACS 0454). We find that 4 out of 17 z ≳ 6 galaxy candidates are favored by z ≲ 1 solutions when IRAC fluxes are included in photometric redshift fitting. We also show that IRAC [3.6]-[4.5] color, when combined with photometric redshift, can be used to identify galaxies which likely have strong nebular emission lines or obscured active galactic nucleus contributions within certain redshift windows.

  12. Aspheric lenses for terahertz imaging.

    PubMed

    Lo, Yat Hei; Leonhardt, Rainer

    2008-09-29

    We present novel designs for aspheric lenses used in terahertz (THz) imaging. As different surfaces result in different beam shaping properties and in different losses from reflection and absorption, the resultant imaging resolution (i.e. the focal spot size) depends critically on the design approach. We evaluate the different lens designs using Kirchhoff's scalar diffraction theory, and test the predictions experimentally. We also show that our lenses can achieve sub-wavelength resolution. While our lens designs are tested with THz radiation, the design considerations are applicable also to other regions of the electro-magnetic spectrum. PMID:18825237

  13. The SNAP Strong Lens Survey

    SciTech Connect

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  14. Detection of stacked filament lensing between SDSS luminous red galaxies

    NASA Astrophysics Data System (ADS)

    Clampitt, Joseph; Miyatake, Hironao; Jain, Bhuvnesh; Takada, Masahiro

    2016-04-01

    We search for the lensing signal of massive filaments between 135 000 pairs of luminous red galaxies (LRGs) from the Sloan Digital Sky Survey. We develop a new estimator that cleanly removes the much larger shear signal of the neighbouring LRG haloes, relying only on the assumption of spherical symmetry. We consider two models: a `thick'-filament model constructed from ray-tracing simulations for Λ cold dark matter model, and a `thin'-filament model which models the filament by a string of haloes along the line connecting the two LRGs. We show that the filament lensing signal is in nice agreement with the thick simulation filament, while strongly disfavouring the thin model. The magnitude of the lensing shear due to the filament is below 10-4. Employing the likelihood ratio test, we find a 4.5σ significance for the detection of the filament lensing signal, corresponding to a null hypothesis fluctuation probability of 3 × 10-6. We also carried out several null tests to verify that the residual shear signal from neighbouring LRGs and other shear systematics are minimized.

  15. Spherical aberration in electrically thin flat lenses.

    PubMed

    Ruphuy, Miguel; Ramahi, Omar M

    2016-08-01

    We analyze the spherical aberration of a new generation of lenses made of flat electrically thin inhomogeneous media. For such lenses, spherical aberration is analyzed quantitatively and qualitatively, and comparison is made to the classical gradient index rod. Both flat thin and thick lenses are made of gradient index materials, but the physical mechanisms and design equations are different. Using full-wave three-dimensional numerical simulation, we evaluate the spherical aberrations using the Maréchal criterion and show that the thin lens gives significantly better performance than the thick lens (rod). Additionally, based on ray tracing formulation, third-order analysis for longitudinal aberration and optical path difference are presented, showing strong overall performance of thin lenses in comparison to classical rod lenses. PMID:27505651

  16. A 30 kpc CHAIN OF ''BEADS ON A STRING'' STAR FORMATION BETWEEN TWO MERGING EARLY TYPE GALAXIES IN THE CORE OF A STRONG-LENSING GALAXY CLUSTER

    SciTech Connect

    Tremblay, Grant R.; Davis, Timothy A.; Gladders, Michael D.; Florian, Michael; Baum, Stefi A.; O'Dea, Christopher P.; Cooke, Kevin C.; Bayliss, Matthew B.; Dahle, Håkon; Rigby, Jane R.; Sharon, Keren; Soto, Emmaris; Wuyts, Eva

    2014-08-01

    New Hubble Space Telescope ultraviolet and optical imaging of the strong-lensing galaxy cluster SDSS J1531+3414 (z = 0.335) reveals two centrally dominant elliptical galaxies participating in an ongoing major merger. The interaction is at least somewhat rich in cool gas, as the merger is associated with a complex network of 19 massive superclusters of young stars (or small tidal dwarf galaxies) separated by ∼1 kpc in projection from one another, combining to an estimated total star formation rate of ∼5 M {sub ☉} yr{sup –1}. The resolved young stellar superclusters are threaded by narrow Hα, [O II], and blue excess filaments arranged in a network spanning ∼27 kpc across the two merging galaxies. This morphology is strongly reminiscent of the well-known ''beads on a string'' mode of star formation observed on kiloparsec scales in the arms of spiral galaxies, resonance rings, and in tidal tails between interacting galaxies. Nevertheless, the arrangement of this star formation relative to the nuclei of the two galaxies is difficult to interpret in a dynamical sense, as no known ''beads on a string'' systems associated with kiloparsec-scale tidal interactions exhibit such lopsided morphology relative to the merger participants. In this Letter, we present the images and follow-up spectroscopy and discuss possible physical interpretations for the unique arrangement of the young stellar clusters. While we suggest that this morphology is likely to be dynamically short-lived, a more quantitative understanding awaits necessary multiwavelength follow-up, including optical integral field spectroscopy, ALMA submillimeter interferometry, and Chandra X-ray imaging.

  17. TOPICAL REVIEW Gravitational lensing

    NASA Astrophysics Data System (ADS)

    Bartelmann, Matthias

    2010-12-01

    Gravitational lensing has developed into one of the most powerful tools for the analysis of the dark universe. This review summarizes the theory of gravitational lensing, its main current applications and representative results achieved so far. It has two parts. In the first, starting from the equation of geodesic deviation, the equations of thin and extended gravitational lensing are derived. In the second, gravitational lensing by stars and planets, galaxies, galaxy clusters and large-scale structures is discussed and summarized.

  18. Gradient Refractive Index Lenses.

    ERIC Educational Resources Information Center

    Morton, N.

    1984-01-01

    Describes the nature of gradient refractive index (GRIN) lenses, focusing on refraction in these materials, focal length of a thin Wood lens, and on manufacturing of such lenses. Indicates that GRIN lenses of small cross section are in limited production with applications suggested for optical communication and photocopying fields. (JN)

  19. CCTV lenses for video meteor astronomy

    NASA Astrophysics Data System (ADS)

    Wiśniewski, M.; Olech, A.; Krasnowski, M.; Zloczewski, K.; Mularczyk, K.; Kedzierski, P.; Jonderko, W.

    2005-02-01

    We present the results of CCTV lens tests made last year at the Ostrowik Observatory by observers of the Comets and Meteors Workshop. A total of 13 lenses with different parameters were tested. The limiting magnitudes, size of field of view, distortion and off-axis aberrations were measured. The Computar f/1.2, f=4 mm appeared to be the best lens tested. We also note the good marks of both Ernitecs which were finally chosen as the lenses which will be used in our projects. Surprisingly, the very fast lenses which are popular in video meteor astronomy seem to be much worse that their f/1.2 rivals.

  20. Investigations of Galaxy Clusters Using Gravitational Lensing

    SciTech Connect

    Wiesner, Matthew P.

    2014-08-01

    In this dissertation, we discuss the properties of galaxy clusters that have been determined using strong and weak gravitational lensing. A galaxy cluster is a collection of galaxies that are bound together by the force of gravity, while gravitational lensing is the bending of light by gravity. Strong lensing is the formation of arcs or rings of light surrounding clusters and weak lensing is a change in the apparent shapes of many galaxies. In this work we examine the properties of several samples of galaxy clusters using gravitational lensing. In Chapter 1 we introduce astrophysical theory of galaxy clusters and gravitational lensing. In Chapter 2 we examine evidence from our data that galaxy clusters are more concentrated than cosmology would predict. In Chapter 3 we investigate whether our assumptions about the number of galaxies in our clusters was valid by examining new data. In Chapter 4 we describe a determination of a relationship between mass and number of galaxies in a cluster at higher redshift than has been found before. In Chapter 5 we describe a model of the mass distribution in one of the ten lensing systems discovered by our group at Fermilab. Finally in Chapter 6 we summarize our conclusions.

  1. An Assessment of the Systematic Uncertainty in Present and Future Tests of the Lense-Thirring Effect with Satellite Laser Ranging

    NASA Astrophysics Data System (ADS)

    Iorio, Lorenzo

    2009-12-01

    We deal with the attempts to measure the Lense-Thirring effect with the Satellite Laser Ranging (SLR) technique applied to the existing LAGEOS and LAGEOS II terrestrial satellites and to the recently approved LARES spacecraft. According to general relativity, a central spinning body of mass M and angular momentum S like the Earth generates a gravitomagnetic field which induces small secular precessions of the orbit of a test particle geodesically moving around it. Extracting this signature from the data is a demanding task because of many classical orbital perturbations having the same pattern as the gravitomagnetic one, like those due to the centrifugal oblateness of the Earth which represents a major source of systematic bias. The first issue addressed here is: are the so far published evaluations of the systematic uncertainty induced by the bad knowledge of the even zonal harmonic coefficients J ℓ of the multipolar expansion of the Earth’s geopotential reliable and realistic? Our answer is negative. Indeed, if the differences Δ J ℓ among the even zonals estimated in different Earth’s gravity field global solutions from the dedicated GRACE mission are assumed for the uncertainties δ J ℓ instead of using their covariance sigmas σ_{J_{ell}} , it turns out that the systematic uncertainty δ μ in the Lense-Thirring test with the nodes Ω of LAGEOS and LAGEOS II may be up to 3 to 4 times larger than in the evaluations so far published (5-10%) based on the use of the sigmas of one model at a time separately. The second issue consists of the possibility of using a different approach in extracting the relativistic signature of interest from the LAGEOS-type data. The third issue is the possibility of reaching a realistic total accuracy of 1% with LAGEOS, LAGEOS II and LARES, which should be launched in November 2009 with a VEGA rocket. While LAGEOS and LAGEOS II fly at altitudes of about 6000 km, LARES will be likely placed at an altitude of 1450 km. Thus

  2. Broadband waveplate lenses.

    PubMed

    Tabiryan, Nelson V; Serak, Svetlana V; Nersisyan, Sarik R; Roberts, David E; Zeldovich, Boris Ya; Steeves, Diane M; Kimball, Brian R

    2016-04-01

    We report on lenses that operate over the visible wavelength band from 450 nm to beyond 700 nm, and other lenses that operate over a wide region in the near-infrared from 650 nm to beyond 1000 nm. Lenses were recorded in liquid crystal polymer layers only a few micrometers thick, using laser-based photoalignment and UV photopolymerization. Waveplate lenses allowed focusing and defocusing laser beams depending on the sign of the circularity of laser beam polarization. Diffraction efficiency of recorded waveplate lenses was up to 90% and contrast ratio was up to 500:1. PMID:27137003

  3. Searching for massive clusters in weak lensing surveys

    NASA Astrophysics Data System (ADS)

    Hamana, Takashi; Takada, Masahiro; Yoshida, Naoki

    2004-05-01

    We explore the ability of weak lensing surveys to locate massive clusters. We use both analytic models of dark matter haloes and mock weak lensing surveys generated from a large cosmological N-body simulation. The analytic models describe the average properties of weak lensing haloes and predict the number counts, enabling us to compute an effective survey selection function. We argue that the detectability of massive haloes depends not only on the halo mass but also strongly on the redshift where the halo is located. We test the model prediction for the peak number counts in weak lensing mass maps against mock numerical data, and find that the noise resulting from intrinsic galaxy ellipticities causes a systematic effect which increases the peak counts. We develop a correction scheme for the systematic effect in an empirical manner, and show that, after correction, the model prediction agrees well with the mock data. The mock data is also used to examine the completeness and efficiency of the weak lensing halo search by fully taking into account the noise and the projection effect by large-scale structures. We show that the detection threshold of S/N = 4 ~ 5 gives an optimal balance between completeness and efficiency. Our results suggest that, for a weak lensing survey with a galaxy number density of ng= 30 arcmin-2 with a mean redshift of z= 1, the mean number of haloes which are expected to cause lensing signals above S/N = 4 is Nhalo(S/N > 4) = 37 per 10 deg2, whereas 23 of the haloes are actually detected with S/N > 4, giving the effective completeness as good as 63 per cent. Alternatively, the mean number of peaks in the same area is Npeak= 62 for a detection threshold of S/N = 4. Among the 62 peaks, 23 are caused by haloes with the expected peak height S/N > 4, 13 result from haloes with 3 < S/N < 4 and the remaining 26 peaks are either the false peaks caused by the noise or haloes with a lower expected peak height. Therefore the contamination rate is 44

  4. Gravitational lensing of active galactic nuclei.

    PubMed Central

    Hewitt, J N

    1995-01-01

    Most of the known cases of strong gravitational lensing involve multiple imaging of an active galactic nucleus. The properties of lensed active galactic nuclei make them promising systems for astrophysical applications of gravitational lensing; in particular, they show structure on scales of milliseconds of arc to tens of seconds of arc, they are variable, and they are polarized. More than 20 cases of strong gravitational lenses are now known, and about half of them are radio sources. High-resolution radio imaging is making possible the development of well-constrained lens models. Variability studies at radio and optical wavelengths are beginning to yield results of astrophysical interest, such as an independent measure of the distance scale and limits on source sizes. PMID:11607613

  5. Testing strong factorial invariance using three-level structural equation modeling.

    PubMed

    Jak, Suzanne

    2014-01-01

    Within structural equation modeling, the most prevalent model to investigate measurement bias is the multigroup model. Equal factor loadings and intercepts across groups in a multigroup model represent strong factorial invariance (absence of measurement bias) across groups. Although this approach is possible in principle, it is hardly practical when the number of groups is large or when the group size is relatively small. Jak et al. (2013) showed how strong factorial invariance across large numbers of groups can be tested in a multilevel structural equation modeling framework, by treating group as a random instead of a fixed variable. In the present study, this model is extended for use with three-level data. The proposed method is illustrated with an investigation of strong factorial invariance across 156 school classes and 50 schools in a Dutch dyscalculia test, using three-level structural equation modeling. PMID:25120499

  6. HerMES: CANDIDATE GRAVITATIONALLY LENSED GALAXIES AND LENSING STATISTICS AT SUBMILLIMETER WAVELENGTHS

    SciTech Connect

    Wardlow, Julie L.; Cooray, Asantha; De Bernardis, Francesco; Calanog, J.; Amblard, A.; Arumugam, V.; Aussel, H.; Bethermin, M.; Blundell, R.; Bussmann, R. S.; Bock, J.; Bridge, C.; Carpenter, J. M.; Boselli, A.; Buat, V.; Burgarella, D.; Cabrera-Lavers, A.; Castro-Rodriguez, N.; Casey, C. M.; and others

    2013-01-01

    We present a list of 13 candidate gravitationally lensed submillimeter galaxies (SMGs) from 95 deg{sup 2} of the Herschel Multi-tiered Extragalactic Survey, a surface density of 0.14 {+-} 0.04 deg{sup -2}. The selected sources have 500 {mu}m flux densities (S {sub 500}) greater than 100 mJy. Gravitational lensing is confirmed by follow-up observations in 9 of the 13 systems (70%), and the lensing status of the four remaining sources is undetermined. We also present a supplementary sample of 29 (0.31 {+-} 0.06 deg{sup -2}) gravitationally lensed SMG candidates with S {sub 500} = 80-100 mJy, which are expected to contain a higher fraction of interlopers than the primary candidates. The number counts of the candidate lensed galaxies are consistent with a simple statistical model of the lensing rate, which uses a foreground matter distribution, the intrinsic SMG number counts, and an assumed SMG redshift distribution. The model predicts that 32%-74% of our S {sub 500} {>=} 100 mJy candidates are strongly gravitationally lensed ({mu} {>=} 2), with the brightest sources being the most robust; this is consistent with the observational data. Our statistical model also predicts that, on average, lensed galaxies with S {sub 500} = 100 mJy are magnified by factors of {approx}9, with apparently brighter galaxies having progressively higher average magnification, due to the shape of the intrinsic number counts. 65% of the sources are expected to have intrinsic 500 {mu}m flux densities less than 30 mJy. Thus, samples of strongly gravitationally lensed SMGs, such as those presented here, probe below the nominal Herschel detection limit at 500 {mu}m. They are good targets for the detailed study of the physical conditions in distant dusty, star-forming galaxies, due to the lensing magnification, which can lead to spatial resolutions of {approx}0.''01 in the source plane.

  7. Lensed Type Ia supernovae as probes of cluster mass models

    NASA Astrophysics Data System (ADS)

    Nordin, J.; Rubin, D.; Richard, J.; Rykoff, E.; Aldering, G.; Amanullah, R.; Atek, H.; Barbary, K.; Deustua, S.; Fakhouri, H. K.; Fruchter, A. S.; Goobar, A.; Hook, I.; Hsiao, E. Y.; Huang, X.; Kneib, J.-P.; Lidman, C.; Meyers, J.; Perlmutter, S.; Saunders, C.; Spadafora, A. L.; Suzuki, N.; Supernova Cosmology Project

    2014-05-01

    Using three magnified Type Ia supernovae (SNe Ia) detected behind CLASH (Cluster Lensing and Supernovae with Hubble) clusters, we perform a first pilot study to see whether standardizable candles can be used to calibrate cluster mass maps created from strong lensing observations. Such calibrations will be crucial when next-generation Hubble Space Telescope cluster surveys (e.g. Frontier) provide magnification maps that will, in turn, form the basis for the exploration of the high-redshift Universe. We classify SNe using combined photometric and spectroscopic observations, finding two of the three to be clearly of Type Ia and the third probable. The SNe exhibit significant amplification, up to a factor of 1.7 at ˜5σ significance (SN-L2). We conducted this as a blind study to avoid fine-tuning of parameters, finding a mean amplification difference between SNe and the cluster lensing models of 0.09 ± 0.09stat ± 0.05sys mag. This impressive agreement suggests no tension between cluster mass models and high-redshift-standardized SNe Ia. However, the measured statistical dispersion of σμ = 0.21 mag appeared large compared to the dispersion expected based on statistical uncertainties (0.14). Further work with the SN and cluster lensing models, post-unblinding, reduced the measured dispersion to σμ = 0.12. An explicit choice should thus be made as to whether SNe are used unblinded to improve the model, or blinded to test the model. As the lensed SN samples grow larger, this technique will allow improved constraints on assumptions regarding e.g. the structure of the dark matter halo.

  8. [Special intra-ocular lenses].

    PubMed

    Jacobi, K W; Nowak, M R; Strobel, J

    1990-01-01

    Intraocular lens (IOL) implantation is the method established worldwide for visual rehabilitation following cataract surgery. IOL's with particular characteristics and/or for special purposes are available for clinical or experimental use. Bifocal and multifocal IOLs have two or more foci for simultaneous far and near vision. The first clinical results are promising. The theoretically expected disadvantages, i.e., reduced contrast sensitivity or reduced visual acuity under reduced contrast conditions, have not yet been found in clinical studies. In cases of age-related macular degeneration, IOLs with a high negative diopter power in the center can be implanted as part of a Galilei telescope. By using high-plus power spectacles, a 2.5x to 4x magnification and a wide field of view can be achieved. Clinical investigation has started recently. Intraocular lenses for the correction of high-grade myopia are being tested by some surgeons. These lenses are made to be implanted in phakic eyes with a clear crystalline lens. Angle-supported and iris-fixated types are under investigation. Longterm results will show the clinical efficacy and safety. Other special intraocular lenses are iris-color lenses and a polymethymethacrylate (PMMA) iris diaphragm. PMID:2083909

  9. Contact Lenses for Vision Correction

    MedlinePlus

    ... Contact Lenses Colored Contact Lenses Contact Lenses for Vision Correction Written by: Kierstan Boyd Reviewed by: Brenda ... on the surface of the eye. They correct vision like eyeglasses do and are safe when used ...

  10. Cosmological parameters from lenses distance ratio

    NASA Astrophysics Data System (ADS)

    Cardone, Vincenzo F.; Piedipalumbo, Ester; Scudellaro, Paolo

    2016-01-01

    Strong lensing provides popular techniques to investigate the mass distribution of intermediate redshift galaxies, testing galaxy evolution and formation scenarios. It especially probes the background cosmic expansion, hence constraining cosmological parameters. The measurement of Einstein radii and central velocity dispersions indeed allows to trace the ratio Ds/Dls between the distance Ds from the observer to the source and the distance Dls from the lens to the source. We present an improved method to explicitly include the two-component structure in the galaxy lens modelling, in order to analyse the role played by the redshift and the model dependence on a nuisance parameter, F_E, which is usually marginalized in the cosmological applications. We show how to deal with these problems and carry on a Fisher matrix analysis to infer the accuracy on cosmological parameters achieved by this method.

  11. Test of weak and strong factorization in nucleus-nucleuscollisions atseveral hundred MeV/nucleon

    SciTech Connect

    La Tessa, Chiara; Sihver, Lembit; Zeitlin, Cary; Miller, Jack; Guetersloh, Stephen; Heilbronn, Lawrence; Mancusi, Davide; Iwata,Yoshiuki; Murakami, Takeshi

    2006-06-21

    Total and partial charge-changing cross sections have been measured for argon projectiles at 400 MeV/nucleon in carbon, aluminum, copper, tin and lead targets; cross sections for hydrogen were also obtained, using a polyethylene target. The validity of weak and strong factorization properties has been investigated for partial charge-changing cross sections; preliminary cross section values obtained for carbon, neon and silicon at 290 and 400 MeV/nucleon and iron at 400 MeV/nucleon, in carbon, aluminum, copper, tin and lead targets have been also used for testing these properties. Two different analysis methods were applied and both indicated that these properties are valid, without any significant difference between weak and strong factorization. The factorization parameters have then been calculated and analyzed in order to find some systematic behavior useful for modeling purposes.

  12. One Episode, Two Lenses

    ERIC Educational Resources Information Center

    Drijvers, Paul; Godino, Juan D.; Font, Vicenc; Trouche, Luc

    2013-01-01

    A deep understanding of students' learning processes is one of the core challenges of research in mathematics education. To achieve this, different theoretical lenses are available. The question is how these different lenses compare and contrast, and how they can be coordinated and combined to provide a more comprehensive view on the topic of…

  13. Learning through Different Lenses

    ERIC Educational Resources Information Center

    Jeweler, Sue; Barnes-Robinson, Linda

    2015-01-01

    When parents and teachers help gifted kids use the metaphor "learning through different lenses," amazing things happen: Horizons open up. Ideas are focused. Thoughts are magnified and clarified. They see the big picture. Metaphoric thinking offers new and exciting ways to see the world. Viewing the world through different lenses provides…

  14. EDITORIAL: Focus on Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Jain, Bhuvnesh

    2007-11-01

    Gravitational lensing emerged as an observational field following the 1979 discovery of a doubly imaged quasar lensed by a foreground galaxy. In the 1980s and '90s dozens of other multiply imaged systems were observed, as well as time delay measurements, weak and strong lensing by galaxies and galaxy clusters, and the discovery of microlensing in our galaxy. The rapid pace of advances has continued into the new century. Lensing is currently one of best techniques for finding and mapping dark matter over a wide range of scales, and also addresses broader cosmological questions such as understanding the nature of dark energy. This focus issue of New Journal of Physics presents a snapshot of current research in some of the exciting areas of lensing. It provides an occasion to look back at the advances of the last decade and ahead to the potential of the coming years. Just about a decade ago, microlensing was discovered through the magnification of stars in our galaxy by invisible objects with masses between that of Jupiter and a tenth the mass of the Sun. Thus a new component of the mass of our galaxy, dubbed MACHOs, was established (though a diffuse, cold dark matter-like component is still needed to make up most of the galaxy mass). More recently, microlensing led to another exciting discovery—of extra-solar planets with masses ranging from about five times that of Earth to that of Neptune. We can expect many more planets to be discovered through ongoing surveys. Microlensing is the best technique for finding Earth mass planets, though it is not as productive overall as other methods and does not allow for follow up observations. Beyond planet hunting, microlensing has enabled us to observe previously inaccessible systems, ranging from the surfaces of other stars to the accretion disks around the black holes powering distant quasars. Galaxies and galaxy clusters at cosmological distances can produce dramatic lensing effects: multiple images of background galaxies

  15. The homogeneity of the retinal illumination is restricted by some ERG lenses.

    PubMed

    Kooijman, A C

    1986-03-01

    Are all types of available electroretinographic contact lenses suited for Ganzfeld stimulation? To answer this question, calculations have been made of the retinal light distribution with several types of ERG lenses placed on a theoretical eye. The results make possible a division of the ERG lenses into three categories. Category 1: Lenses with which the homogeneity of the retinal illumination is nearly perfect and independent of pupil size. These lenses are especially well designed for Ganzfeld electroretinography. Category 2: Lenses which illuminate a large retinal area but with which the light distribution depends on the size of the pupil. The suitability of these lenses is questionable, because Ganzfeld electroretinography is used in order to obtain a homogeneous retinal light distribution under most conditions. Category 3: Lenses with which the size of the illuminated retinal area changes strongly with the size of the pupil. These lenses are unsuitable for Ganzfeld electroretinography. PMID:3949465

  16. High-voltage pulse testing of DSSL (detonator strong safety link) actuator drive cables

    SciTech Connect

    Neau, E.L.; Laderach, G.E.

    1990-05-01

    A series of test has evaluated the current-carrying characteristics of several proposed detonator strong safety link (DSSL) drive cables to conduct current into an electrically simulated radiation case enclosure. The drive cables tested included a dielectric cable made up of either one or two braided Kevlar threads in a polysulfone sleeve, an existing DSSL conductive drive cable similar to a bicycle shift cable, with and without an external ground-strap diversion feature, and the flex circuit hook assembly used for DSSL instrumentation purposes. Each of the test samples was connected to a 200-kV, 30-kA Marx generator and terminated inside an electrically simulated radiation case enclosure. Two lengths of drive cables (4 and 13 in.) within the simulated radiation case were tested for each type. The results indicate that the conductive drive cables without an external short-circuit diversion feature conducted about 5 to 9 times as much current into the simulated radiation case as either the dielectric drive cables or the conductive drive cables with an external short-circuit feature. Surprisingly, the flex circuit hook assemblies, both the short and long cables, conducted nearly 100% of the available current into the simulated radiation case enclosure. The next series of experiments will repeat the tests at the SNL Lightning Facility in order to scale the results up to the maximum lightning threat levels of 200 kA. 18 figs., 1 tab.

  17. Optimizing SNAP for Weak Lensing

    NASA Astrophysics Data System (ADS)

    High, F. W.; Ellis, R. S.; Massey, R. J.; Rhodes, J. D.; Lamoureux, J. I.; SNAP Collaboration

    2004-12-01

    The Supernova/Acceleration Probe (SNAP) satellite proposes to measure weak gravitational lensing in addition to type Ia supernovae. Its pixel scale has been set to 0.10 arcsec per pixel as established by the needs of supernova observations. To find the optimal pixel scale for accurate weak lensing measurements we conduct a tradeoff study in which, via simulations, we fix the suvey size in total pixels and vary the pixel scale. Our preliminary results show that with a smaller scale of about 0.08 arcsec per pixel we can minimize the contribution of intrinsic shear variance to the error on the power spectrum of mass density distortion. Currently we are testing the robustness of this figure as well as determining whether dithering yields analogous results.

  18. Multimodal characterization of contact lenses

    NASA Astrophysics Data System (ADS)

    Marcus, Michael A.; Compertore, David; Gibson, Donald S.; Herbrand, Matthew E.; Ignatovich, Filipp V.

    2015-10-01

    A table top instrument has been designed, constructed and tested to characterize all of the primary optical and physical properties of contact lenses. Measured optical properties include base power, cylinder power, cylindrical axis, prism, refractive index and wavefront aberrations. Measured physical properties include center thickness, lens diameter and lens sagittal depth. The instrument combines a Shack-Hartmann wavefront sensor (SHWS), a machine vision sensor, and a low coherence light interferometer (LCI) all coaxially aligned into a single tabletop unit. The unit includes a cuvette, mounted in a translatable sample chamber for holding the contact lens under test, and it can be configured to measure wet or dry contact lenses. During operation, the vision sensor measures the diameter of the lens, and locates the center of the lens. The lens is then aligned for other measurements. The vision sensor can also measure various alignment marks on the lens, as well as identify any alpha numerical features, which can be used to associate the lens orientation with the measured aberrations. The LCI measures the center thickness, sagittal depth and index of refraction of the contact lens. The base radius of curvature is then calculated using these measured parameters. The SHWS measures the lenses prescription power, including spherical, cylinder, prism, and higher order wavefront aberrations. NIST traceable calibration artifacts are used to calibrate the SHWS, machine vision and LCI modalities. Repeatability measurements on a contact lens in a saline solution are presented.

  19. Stress-Detection Lenses

    NASA Technical Reports Server (NTRS)

    1996-01-01

    An Ames Research Center scientist invented an infrared lens used in sunglasses to filter out ultraviolet rays. This product finds its origins in research for military enemy detection. Through a Space Act Agreement, Optical Sales Corporation introduced the Hawkeye Lenses not only as sunglasses but as plant stress detection lenses. The lenses enhance the stressed part of the leaf, which has less chlorophyll than healthy leaves, through dyes that filter out certain wavelengths of light. Plant stress is visible earlier, at a stage when something can be done to save the plants.

  20. Final report on repair procedure of strong ground motion data from underground nuclear tests

    SciTech Connect

    Tunnell, T.W.

    1995-04-01

    Certain difficulties arise when recording close-in around motion from underground nuclear explosions. Data quality can be compromised by a variety of factors, including electromagnetic pulse, noise spikes, direct current effect, and gauge clipping and gauge tilt. From March 1988 through September 1994, EG&G Energy Measurements repaired strong round-motion data (acceleration data) from underground nuclear tests for the Los Alamos National Laboratory using, an automated repair procedure. The automated repair determined and implemented the required repairs based on user input and a consistent set of criteria. A log was kept of each repair so that the repair procedure could be duplicated. This relaxed the requirement to save the repaired data. Developed for the VAX system, the procedure allowed the user to stack up a large number of repairs, plot the repaired data, and obtain hard copies. The plotted data could then be reviewed for a given test to determine the consistency of repair for a given underground test. This feature released the user to perform other tasks while the data were being repaired.

  1. Testing the strong equivalence principle with spacecraft ranging towards the nearby Lagrangian points

    NASA Astrophysics Data System (ADS)

    Congedo, Giuseppe; De Marchi, Fabrizio

    2016-05-01

    General relativity is supported by great experimental evidence. Yet there is a lot of interest in precisely setting its limits with on going and future experiments. A question to answer is about the validity of the strong equivalence principle. Ground experiments and lunar laser ranging have provided the best upper limit on the Nordtvedt parameter σ [η ]=4.4 ×10-4 . With the future planetary mission BepiColombo, this parameter will be further improved by at least an order of magnitude. In this paper we envisage yet another possible testing environment with spacecraft ranging towards the nearby Sun-Earth collinear Lagrangian points. Neglecting errors in planetary masses and ephemerides, we forecast σ [η ]=6.4 (2.0 )×10-4 (5 yr integration time) via ranging towards L1 in a realistic (optimistic) scenario depending on current (future) range capabilities and knowledge of the Earth's ephemerides. A combined measurement, L1+L2, gives instead 4.8 (1.7 )×10-4. In the optimistic scenario a single measurement of one year would be enough to reach ≈3 ×10-4. All figures are comparable with lunar laser ranging, but worse than BepiColombo. Performances could be much improved if data were integrated over time and over the number of satellites flying around either of the two Lagrangian points. We point out that some systematics (gravitational perturbations of other planets or figure effects) are much more in control compared to other experiments. We do not advocate a specific mission to constrain the strong equivalence principle, but we do suggest analyzing ranging data of present and future spacecrafts flying around L1/L2 (one key mission is, for instance, LISA Pathfinder). This spacecraft ranging would be a new and complementary probe to constrain the strong equivalence principle in space.

  2. [Phakic intraocular lenses].

    PubMed

    Kohnen, T; Shajari, M

    2016-06-01

    Refractive surgical procedures are generally divided into additive procedures with, e. g. implantation of an artificial lens and subtractive procedures with ablation of corneal tissue. In this article the current status of phakic intraocular lens (IOL) implantation for correction of refractive errors is reviewed. Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and sulcus-fixated posterior chamber lenses. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and depend to a large extent on the location. For anterior chamber lenses the main concern is critical endothelial cell loss and for posterior chamber lenses early cataract formation. PMID:27277751

  3. Gravitational Lensing: Einstein's unfinished symphony

    NASA Astrophysics Data System (ADS)

    Treu, Tommaso; Ellis, Richard S.

    2015-01-01

    Gravitational lensing - the deflection of light rays by gravitating matter - has become a major tool in the armoury of the modern cosmologist. Proposed nearly a hundred years ago as a key feature of Einstein's theory of general relativity, we trace the historical development since its verification at a solar eclipse in 1919. Einstein was apparently cautious about its practical utility and the subject lay dormant observationally for nearly 60 years. Nonetheless there has been rapid progress over the past twenty years. The technique allows astronomers to chart the distribution of dark matter on large and small scales thereby testing predictions of the standard cosmological model which assumes dark matter comprises a massive weakly-interacting particle. By measuring the distances and tracing the growth of dark matter structure over cosmic time, gravitational lensing also holds great promise in determining whether the dark energy, postulated to explain the accelerated cosmic expansion, is a vacuum energy density or a failure of general relativity on large scales. We illustrate the wide range of applications which harness the power of gravitational lensing, from searches for the earliest galaxies magnified by massive clusters to those for extrasolar planets which temporarily brighten a background star. We summarise the future prospects with dedicated ground and space-based facilities designed to exploit this remarkable physical phenomenon.

  4. Developments in modern panoramic lenses: lens design, controlled distortion, and characterization

    NASA Astrophysics Data System (ADS)

    Thibault, Simon; Parent, Jocelyn; Zhang, Hu; Larivière-Bastien, Martin; Poulin-Girard, Anne-Sophie; Arfaoui, Aymen; Désaulniers, Pierre

    2011-11-01

    Almost every aspect concerning the design of modern panoramic lenses brings new challenges to optical designers. Examples of these include ray tracing programs having problems finding the entrance pupil which is moving through the field of view, production particularities due to the shape of the front lenses, ways of tolerancing these systems having strong distortion, particular setups required for their characterization and calibration, and algorithms to properly analyze and make use of the obtained images. To better understand these modern panoramic lenses, the Optical Engineering Research Laboratory at Laval University has been doing research on them during the past few years. The most significant results are being presented in this paper. Controlled distortion, as in commercial panomorph lenses (Immervision), is used to image a specific part of the object with more pixels than in a normal fisheye lens. This idea is even more useful when a zone of interest vary in time with dynamically adjustable distortion as in a panoramic locally magnifying imager. Another axis of research is the use of modern computational techniques such as wavefront coding in wide-angle imaging systems. The particularities of such techniques when the field of view is large or with anamorphic imagers are considered. Presentation of a novel circular test bench in our laboratories, required to calibrate and check the image quality of wide-angle imaging system, follows. Another presented setup uses a laser and diffractive optical elements to compactly calibrate wide-angle lenses. Then, a discussion of the uniqueness in tolerancing these lenses, especially the front elements due to the large ratio between lens diameter and entrance pupil diameter, is included. Lastly, particularities with polarization imaging and experiments of triangle orientation detection tests before and after unwrapping the distorted images are briefly discussed.

  5. Three Gravitationally Lensed Supernovae Behind Clash Galaxy Clusters

    NASA Technical Reports Server (NTRS)

    Patel, Brandon; McCully, Curtis; Jha, Saurbh W.; Rodney, Steven A.; Jones, David O.; Graur, Or; Merten, Julian; Zitrin, Adi; Riess, Adam G.; Matheson, Thomas; Sako, Masao; Holoien, Thomas W. -S.; Postman, Marc; Coe, Dan; Bartelmann, Matthias; Balestra, Italo; Benitez, Narciso; Bouwens, Rychard; Bradley, Larry; Broadhurst, Tom; Cenko, Stephen Bradley; Donahue, Megan; Filippenko, Alexei V.; Ford, Holland; Garnavich, Peter; Grillo, Claudio; Infante, Leopoldo; Jouvel, Stephanie; Kelson, Daniel; Koekemoer, Anton; Lahav, Ofer; Lemze, Doron; Maoz, Dan; Medezinski, Elinor; Melchior, Peter; Meneghetti, Massimo; Molino, Alberto; Moustakas, John; Moustakas, Leonidas A.; Nonino, Mario; Rosati, Piero; Seitz, Stella; Strolger, Louis G.; Umetsu, Keiichi; Zheng, Wei

    2014-01-01

    We report observations of three gravitationally lensed supernovae (SNe) in the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program. These objects, SN CLO12Car (z = 1.28), SN CLN12Did (z = 0.85), and SN CLA11Tib (z = 1.14), are located behind three different clusters, MACSJ1720.2+3536 (z = 0.391), RXJ1532.9+3021 (z = 0.345), and A383 (z = 0.187), respectively. Each SN was detected in Hubble Space Telescope optical and infrared images. Based on photometric classification, we find that SNe CLO12Car and CLN12Did are likely to be Type Ia supernovae (SNe Ia), while the classification of SN CLA11Tib is inconclusive. Using multi-color light-curve fits to determine a standardized SN Ia luminosity distance, we infer that SN CLO12Car was approx. 1.0 +/- 0.2 mag brighter than field SNe Ia at a similar redshift and ascribe this to gravitational lens magnification. Similarly, SN CLN12Did is approx. 0.2 +/- 0.2 mag brighter than field SNe Ia. We derive independent estimates of the predicted magnification from CLASH strong+weak-lensing maps of the clusters (in magnitude units, 2.5 log10 µ): 0.83 +/- 0.16 mag for SN CLO12Car, 0.28 +/- 0.08 mag for SN CLN12Did, and 0.43 +/- 0.11 mag for SN CLA11Tib. The two SNe Ia provide a new test of the cluster lens model predictions: we find that the magnifications based on the SN Ia brightness and those predicted by the lens maps are consistent. Our results herald the promise of future observations of samples of cluster-lensed SNe Ia (from the ground or space) to help illuminate the dark-matter distribution in clusters of galaxies, through the direct determination of absolute magnifications.

  6. Early Weak Lensing Results From The Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Maccrann, Niall; Dark Energy Survey Collaboration

    2016-01-01

    I present the early weak lensing results, including cosmological constraints, from the Dark Energy Survey (DES). Although only 3% of the final survey, DES Science Verification data already constituted a competitive weak lensing dataset, and the thoroughly tested shear catalogs allowed a number of interesting science analyses including cosmology from cosmic shear, mass mapping, combining lensing with galaxy clustering and combining with CMB lensing. I will summarize the main results of these analyses, discuss common systematic effects which need to be addressed to take advantage of the greater statistical power of main survey data, and outline some of improvements at various stages of the analysis pipeline that aim to do this.

  7. Evaporated As2S3 Luneburg lenses for LiNbO3:Ti optical waveguides

    NASA Technical Reports Server (NTRS)

    Busch, J. R.; Wood, V. E.; Kenan, R. P.; Verber, C. M.

    1981-01-01

    Luneburg lenses of good quality were formed on high index optical waveguides by evaporation of arsenic trisulfide glass through simple masks. Using only two thin circular aperture masks, lenses with focal spots of a few times the diffraction limited width at f/4 were obtained. These lenses were designed for and tested at both visible (633 nm) and infrared wavelengths. Procedures for the design, fabrication, and testing of lenses of this type are described.

  8. Compound lensing: Einstein zig-zags and high-multiplicity lensed images

    NASA Astrophysics Data System (ADS)

    Collett, Thomas E.; Bacon, David J.

    2016-02-01

    Compound strong gravitational lensing is a rare phenomenon, but a handful of such lensed systems are likely to be discovered in forthcoming surveys. In this work, we use a double singular isothermal sphere lens model to analytically understand how the properties of the system impact image multiplicity for the final source. We find that up to six images of a background source can form, but only if the second lens is multiply imaged by the first and the Einstein radius of the second lens is comparable to, but does not exceed that of the first. We then build a model of compound lensing masses in the Universe, using singular isothermal ellipsoid (SIE) lenses, and assess how the optical depth for multiple imaging by a galaxy-galaxy compound lens varies with source redshift. For a source redshift of 4, we find optical depths of 6 × 10-6 for multiple imaging and 5 × 10-8 for multiplicity of 6 or greater. We find that extreme magnifications are possible, with magnifications of 100 or more for 6 × 10-9 of z = 10 sources with 0.1 kpc radii. We show some of the image configurations that can be generated by compound lenses, and demonstrate that they are qualitatively different to those generated by single-plane lenses; dedicated compound lens finders will be necessary if these systems are to be discovered in forthcoming surveys.

  9. Spin Correlations of Strongly Interacting Massive Fermion Pairs as a Test of Bell's Inequality

    SciTech Connect

    Sakai, H.; Saito, T.; Kuboki, H.; Sasano, M.; Yako, K.; Ikeda, T.; Itoh, K.; Kawabata, T.; Maeda, Y.; Suda, K.; Uesaka, T.; Matsui, N.; Satou, Y.; Rangacharyulu, C.; Sekiguchi, K.; Tamii, A.

    2006-10-13

    We report the results of the first-time test of the local hidden variable theories (Bell-Clauser-Horne-Shimony-Holt) involving strongly interacting pairs of massive spin 1/2 hadrons from the decay of short-lived ({tau}<10{sup -21}sec) {sup 2}He spin-singlet state, populated in the nuclear reaction {sup 2}H+{sup 1}H{yields}{sup 2}He+n. The novel features of this experiment are (a) the use of an 'event body' detector of nearly 100% efficiency to prepare an unbiased sample and (b) a focal-plane polarimeter of full 2{pi} sr acceptance with a random 'post selection' of the reference axes. The spin-correlation function is deduced to be S{sub exp}({pi}/4)=2.83{+-}0.24{sub stat}{+-}0.07{sub sys}. This result is in agreement with nonlocal quantum mechanical prediction and it violates the Bell-CHSH inequality of vertical bar S vertical bar{<=}2 at a confidence level of 99.3%.

  10. Gravitational lensing of gravitational waves from merging neutron star binaries

    SciTech Connect

    Wang, Yun; Stebbins, Albert; Turner, Edwin L.

    1996-05-01

    We discuss the gravitational lensing of gravitational waves from merging neutron star binaries, in the context of advanced LIGO type gravitational wave detectors. We consider properties of the expected observational data with cut on the signal-to-noise ratio \\rho, i.e., \\rho>\\rho_0. An advanced LIGO should see unlensed inspiral events with a redshift distribution with cut-off at a redshift z_{\\rm max} < 1 for h \\leq 0.8. Any inspiral events detected at z>z_{\\rm max} should be lensed. We compute the expected total number of events which are present due to gravitational lensing and their redshift distribution for an advanced LIGO in a flat Universe. If the matter fraction in compact lenses is close to 10\\%, an advanced LIGO should see a few strongly lensed events per year with \\rho >5.

  11. Differential gauging and tracer tests resolve seepage fluxes in a strongly-losing stream

    NASA Astrophysics Data System (ADS)

    Ruehl, C.; Fisher, A. T.; Hatch, C.; Huertos, M. Los; Stemler, G.; Shennan, C.

    2006-10-01

    SummaryThe Pajaro River, central coastal California, consistently loses 0.2-0.4 m 3/s of discharge along an 11.42-km experimental reach late in the water year, when discharge is ⩽4.5 m 3/s. Channel loss occurs throughout this reach, but is greatest in magnitude near the bottom of the reach. Water isotopic data and other observations suggest that channel loss results mainly from streambed seepage, as opposed to evapotranspiration. If it occurs throughout the year, the channel loss along this short stream reach could contribute 6-13 × 10 6 m 3 of annual aquifer recharge, or ˜20-40% of current sustainable basin yield. We performed a series of tracer injections along this reach to determine if hydrologic exchange occurs within this strongly-losing stream. We found that during periods of high channel loss, there were also comparable storage exchange fluxes and lateral inflow of tracer-free water. Within upper and lower parts of the experimental reach, storage exchange fluxes are about 10 times greater than lateral inflow. The former are associated with the movement of water between the main channel and surface or subsurface storage zones. In this system, it is likely that the latter are primarily associated with spatially- or temporally-long subsurface flow paths within the shallow streambed, as opposed to inflow of ground water from deeper in the basin. Along both upper and lower parts of the experimental reach, lateral inflow tends to increase as channel discharge decreases. In contrast, storage exchange fluxes increase with decreasing discharge along the upper parts of the reach, but decrease with decreasing discharge along the lower parts. Gauging and tracer test results suggest that subsurface storage exchange and loss may occur simultaneously, and that the lateral inflow of tracer-free water can be caused by long-scale subsurface flow as well as ground water making its first appearance in the channel.

  12. Radiation Blocking Lenses

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Biomedical Optical Company of America's (BOCA) suntiger lenses, similar in principle to natural filters in the eyes of hawks and eagles, bar 99 percent of potentially harmful wavelengths, while allowing visually useful colors of light (red, orange, green) to pass through. They also improve visual acuity, night vision and haze or fog visibility. The lenses evolved from work done by James B. Stephens and Dr. Charles G. Miller of the Jet Propulsion Laboratory. They developed a formula and produced a commercial welding curtain that absorbs, filters, and scatters light. This research led to protective glasses now used by dentists, workers in hazardous environments, CRT operators and skiers.

  13. Plasma lenses for focusing relativistic electron beams

    SciTech Connect

    Govil, R.; Wheeler, S.; Leemans, W.

    1997-04-01

    The next generation of colliders require tightly focused beams with high luminosity. To focus charged particle beams for such applications, a plasma focusing scheme has been proposed. Plasma lenses can be overdense (plasma density, n{sub p} much greater than electron beam density, n{sub b}) or underdense (n{sub p} less than 2 n{sub b}). In overdense lenses the space-charge force of the electron beam is canceled by the plasma and the remaining magnetic force causes the electron beam to self-pinch. The focusing gradient is nonlinear, resulting in spherical aberrations. In underdense lenses, the self-forces of the electron beam cancel, allowing the plasma ions to focus the beam. Although for a given beam density, a uniform underdense lens produces smaller focusing gradients than an overdense lens, it produces better beam quality since the focusing is done by plasma ions. The underdense lens can be improved by tapering the density of the plasma for optimal focusing. The underdense lens performance can be enhanced further by producing adiabatic plasma lenses to avoid the Oide limit on spot size due to synchrotron radiation by the electron beam. The plasma lens experiment at the Beam Test Facility (BTF) is designed to study the properties of plasma lenses in both overdense and underdense regimes. In particular, important issues such as electron beam matching, time response of the lens, lens aberrations and shot-to-shot reproducibility are being investigated.

  14. Weak lensing corrections to tSZ-lensing cross correlation

    NASA Astrophysics Data System (ADS)

    Tröster, Tilman; Van Waerbeke, Ludovic

    2014-11-01

    The cross correlation between the thermal Sunyaev-Zeldovich (tSZ) effect and gravitational lensing in wide field has recently been measured. It can be used to probe the distribution of the diffuse gas in large scale structure, as well as inform us about the missing baryons. As for any lensing-based quantity, higher order lensing effects can potentially affect the signal. Here, we extend previous higher order lensing calculations to the case of tSZ-lensing cross correlations. We derive terms analogous to corrections due to the Born approximation, lens-lens coupling, and reduced shear up to order l gtrsim 3000.

  15. Strong-field tests of f(R)-gravity in binary pulsars

    NASA Astrophysics Data System (ADS)

    Dyadina, Polina I.; Alexeyev, Stanislav O.; Capozziello, Salvatore; de Laurentis, Mariafelicia; Rannu, Kristina A.

    2016-03-01

    We develop the parameterized post-Keplerian approach for class of analytic f(R)-gravity models. Using the double binary pulsar system PSR J0737-3039 data we obtain restrictions on the parameters of this class of f(R)-models and show that f(R)-gravity is not ruled out by the observations in strong field regime. The additional and more strong corresponding restriction is extracted from solar system data.

  16. The Master Lens Database and The Orphan Lenses Project

    NASA Astrophysics Data System (ADS)

    Moustakas, Leonidas

    2012-10-01

    Strong gravitational lenses are uniquely suited for the study of dark matter structure and substructure within massive halos of many scales, act as gravitational telescopes for distant faint objects, and can give powerful and competitive cosmological constraints. While hundreds of strong lenses are known to date, spanning five orders of magnitude in mass scale, thousands will be identified this decade. To fully exploit the power of these objects presently, and in the near future, we are creating the Master Lens Database. This is a clearinghouse of all known strong lens systems, with a sophisticated and modern database of uniformly measured and derived observational and lens-model derived quantities, using archival Hubble data across several instruments. This Database enables new science that can be done with a comprehensive sample of strong lenses. The operational goal of this proposal is to develop the process and the code to semi-automatically stage Hubble data of each system, create appropriate masks of the lensing objects and lensing features, and derive gravitational lens models, to provide a uniform and fairly comprehensive information set that is ingested into the Database. The scientific goal for this team is to use the properties of the ensemble of lenses to make a new study of the internal structure of lensing galaxies, and to identify new objects that show evidence of strong substructure lensing, for follow-up study. All data, scripts, masks, model setup files, and derived parameters, will be public, and free. The Database will be accessible online and through a sophisticated smartphone application, which will also be free.

  17. Fresnel's Lighthouse Lenses

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2007-01-01

    One of the rewards of walking up the scores of steps winding around the inside of the shaft of a lighthouse is turning inward and examining the glass optical system. This arrangement of prisms, lenses, and reflectors is used to project the light from a relatively small source in a beam that can be seen far at sea.

  18. Rainwater lenses in wetlands

    NASA Astrophysics Data System (ADS)

    Dekker, S. C.; Schot, P. P.; Bootsma, M. C.

    2003-04-01

    In the Netherlands, drainage and groundwater abstraction in wetlands has lead to deterioration of fen vegetation through lowering of the phreatic level. This enables recharge of local, acid precipitation and the development of rainwater lenses which float on alkaline groundwater. These lenses prevent upward seeping of the groundwater reaching the fen root zone. In the nature reserve Ilperveld (The Netherlands), a ditch/trench system was dug for the purpose of creating run-off for acid rainwater in wet periods, and to enable neutral surface water in dry periods. Sods were removed to decrease the evapotranspiration. Knowledge of the form and behaviour of rainwater lenses in the root zone of wetlands is a prerequisite in fen restoration projects in order to design effective and cost-efficient measures. With a saturated-unsaturated solute transport model (HYDRUS-2D), numerical simulations were performed. Model results are compared with temporal and spatial measurements of electrical conductivity measured in the Ilperveld. Furthermore, results of temporal dynamics of rainwater lenses are shown as function of (i) the phreatic level, (ii) the number of drainage canals and (iii) the groundwater inflow fluxes.

  19. BIASES IN PHYSICAL PARAMETER ESTIMATES THROUGH DIFFERENTIAL LENSING MAGNIFICATION

    SciTech Connect

    Er Xinzhong; Ge Junqiang; Mao Shude

    2013-06-20

    We study the lensing magnification effect on background galaxies. Differential magnification due to different magnifications of different source regions of a galaxy will change the lensed composite spectra. The derived properties of the background galaxies are therefore biased. For simplicity, we model galaxies as a superposition of an axis-symmetric bulge and a face-on disk in order to study the differential magnification effect on the composite spectra. We find that some properties derived from the spectra (e.g., velocity dispersion, star formation rate, and metallicity) are modified. Depending on the relative positions of the source and the lens, the inferred results can be either over- or underestimates of the true values. In general, for an extended source at strong lensing regions with high magnifications, the inferred physical parameters (e.g., metallicity) can be strongly biased. Therefore, detailed lens modeling is necessary to obtain the true properties of the lensed galaxies.

  20. Tested Demonstrations: Comparison of Strong Acid and Weak Acid Titration Curves.

    ERIC Educational Resources Information Center

    Gilbert, George L., Ed.

    1979-01-01

    A lecture demonstration is presented for comparing titration curves. A plot of pH vs volume of strong base is produced by connecting the external output of a pH meter to a strip recorder. Thus, pH is recorded as a function of time. (BB)

  1. Time delay and magnification centroid due to gravitational lensing by black holes and naked singularities

    SciTech Connect

    Virbhadra, K. S.; Keeton, C. R.

    2008-06-15

    We model the massive dark object at the center of the Galaxy as a Schwarzschild black hole as well as Janis-Newman-Winicour naked singularities, characterized by the mass and scalar charge parameters, and study gravitational lensing (particularly time delay, magnification centroid, and total magnification) by them. We find that the lensing features are qualitatively similar (though quantitatively different) for Schwarzschild black holes, weakly naked, and marginally strongly naked singularities. However, the lensing characteristics of strongly naked singularities are qualitatively very different from those due to Schwarzschild black holes. The images produced by Schwarzschild black hole lenses and weakly naked and marginally strongly naked singularity lenses always have positive time delays. On the other hand, strongly naked singularity lenses can give rise to images with positive, zero, or negative time delays. In particular, for a large angular source position the direct image (the outermost image on the same side as the source) due to strongly naked singularity lensing always has a negative time delay. We also found that the scalar field decreases the time delay and increases the total magnification of images; this result could have important implications for cosmology. As the Janis-Newman-Winicour metric also describes the exterior gravitational field of a scalar star, naked singularities as well as scalar star lenses, if these exist in nature, will serve as more efficient cosmic telescopes than regular gravitational lenses.

  2. Millimeter-wave antireflection coating for cryogenic silicon lenses.

    PubMed

    Lau, Judy; Fowler, Joseph; Marriage, Tobias; Page, Lyman; Leong, Jon; Wishnow, Edward; Henry, Ross; Wollack, Ed; Halpern, Mark; Marsden, Danica; Marsden, Gaelen

    2006-06-01

    We have developed and tested an antireflection (AR) coating method for silicon lenses used at cryogenic temperatures and millimeter wavelengths. Our particular application is a measurement of the cosmic microwave background. The coating consists of machined pieces of Cirlex glued to the silicon. The measured reflection from an AR-coated flat piece is less than 1.5% at the design wavelength. The coating has been applied to flats and lenses and has survived multiple thermal cycles from 300 to 4 K. We present the manufacturing method, the material properties, the tests performed, and estimates of the loss that can be achieved in practical lenses. PMID:16724132

  3. Probing spacetime noncommutative constant via charged astrophysical black hole lensing

    NASA Astrophysics Data System (ADS)

    Ding, Chikun; Jing, Jiliang

    2011-10-01

    We study the influence of the spacetime noncommutative parameter on the strong field gravitational lensing in the noncommutative Reissner-Nordström black-hole spacetime. Supposing that the gravitational field of the supermassive central object of the Galaxy is described by this metric, we estimate the numerical values of the coefficients and observables for strong gravitational lensing. Our results show that with the increase of the parameter sqrt {\\vartheta } , the observables θ ∞ and r m decrease, while s increases. Our results also show that i) if sqrt {\\vartheta } is strong, the observables are close to those of the noncommutative Schwarzschild black hole lensing; ii) if sqrt {\\vartheta } is weak, the observables are close to those of the commutative Reissner-Nordström black hole lensing; iii) the detectable scope of ϑ in a noncommutative Reissner-Nordström black hole lensing is 0.12 ≤ sqrt {\\vartheta } ≤ 0.26 , which is wider than that in a noncommutative Schwarzschild black hole lensing, 0.18 ≤ sqrt {\\vartheta } ≤ 0.26 . This may offer a way to probe the spacetime noncommutative constant ϑ by the astronomical instruments in the future.

  4. Chitah: Strong-gravitational-lens Hunter in Imaging Surveys

    NASA Astrophysics Data System (ADS)

    Chan, James H. H.; Suyu, Sherry H.; Chiueh, Tzihong; More, Anupreeta; Marshall, Philip J.; Coupon, Jean; Oguri, Masamune; Price, Paul

    2015-07-01

    Strong gravitationally lensed quasars provide powerful means to study galaxy evolution and cosmology. Current and upcoming imaging surveys will contain thousands of new lensed quasars, augmenting the existing sample by at least two orders of magnitude. To find such lens systems, we built a robot, Chitah, that hunts for lensed quasars by modeling the configuration of the multiple quasar images. Specifically, given an image of an object that might be a lensed quasar, Chitah first disentangles the light from the supposed lens galaxy and the light from the multiple quasar images based on color information. A simple rule is designed to categorize the given object as a potential four-image (quad) or two-image (double) lensed quasar system. The configuration of the identified quasar images is subsequently modeled to classify whether the object is a lensed quasar system. We test the performance of Chitah using simulated lens systems based on the Canada-France-Hawaii Telescope Legacy Survey. For bright quads with large image separations (with Einstein radius {r}{ein}\\gt 1\\buildrel{\\prime\\prime}\\over{.} 1) simulated using Gaussian point-spread functions, a high true-positive rate (TPR) of ˜ 90% and a low false-positive rate of ˜ 3% show that this is a promising approach to search for new lens systems. We obtain high TPR for lens systems with {r}{ein}≳ 0\\buildrel{\\prime\\prime}\\over{.} 5, so the performance of Chitah is set by the seeing. We further feed a known gravitational lens system, COSMOS 5921+0638, to Chitah, and demonstrate that Chitah is able to classify this real gravitational lens system successfully. Our newly built Chitah is omnivorous and can hunt in any ground-based imaging surveys.

  5. Real-time rendering method and performance evaluation of composable 3D lenses for interactive VR.

    PubMed

    Borst, Christoph W; Tiesel, Jan-Phillip; Best, Christopher M

    2010-01-01

    We present and evaluate a new approach for real-time rendering of composable 3D lenses for polygonal scenes. Such lenses, usually called "volumetric lenses," are an extension of 2D Magic Lenses to 3D volumes in which effects are applied to scene elements. Although the composition of 2D lenses is well known, 3D composition was long considered infeasible due to both geometric and semantic complexity. Nonetheless, for a scene with multiple interactive 3D lenses, the problem of intersecting lenses must be considered. Intersecting 3D lenses in meaningful ways supports new interfaces such as hierarchical 3D windows, 3D lenses for managing and composing visualization options, or interactive shader development by direct manipulation of lenses providing component effects. Our 3D volumetric lens approach differs from other approaches and is one of the first to address efficient composition of multiple lenses. It is well-suited to head-tracked VR environments because it requires no view-dependent generation of major data structures, allowing caching and reuse of full or partial results. A Composite Shader Factory module composes shader programs for rendering composite visual styles and geometry of intersection regions. Geometry is handled by Boolean combinations of region tests in fragment shaders, which allows both convex and nonconvex CSG volumes for lens shape. Efficiency is further addressed by a Region Analyzer module and by broad-phase culling. Finally, we consider the handling of order effects for composed 3D lenses. PMID:20224135

  6. Harmonic diffractive lenses

    SciTech Connect

    Sweeney, D.W.; Sommargren, G.E.

    1995-05-10

    The harmonic diffractive lens is a diffractive imaging lens for which the optical path-length transition between adjacent facets is an integer multiple {ital m} of the design wavelength {lambda}{sub 0}. The total lens thickness in air is {ital m}{lambda}{sub 0}/({ital n} {minus} 1), which is {ital m} times thicker than the so-called modulo 2{pi} diffractive lens. Lenses constructed in this way have hybrid properties of both refractive and diffractive lenses. Such a lens will have a diffraction-limited, common focus for a number of discrete wavelengths across the visible spectrum. A 34.75-diopter, 6-mm-diameter lens is diamond turned in aluminum and replicated in optical materials. The sag of the lens is 23 {mu}m. Modulation transfer function measurements in both monochromatic and white light verify the performance of the lens. The lens approaches the diffraction limit for 10 discrete wavelengths across the visible spectrum.

  7. The effect of weak lensing on distance estimates from supernovae

    SciTech Connect

    Smith, Mathew; Maartens, Roy; Bacon, David J.; Nichol, Robert C.; Campbell, Heather; D'Andrea, Chris B.; Clarkson, Chris; Bassett, Bruce A.; Cinabro, David; Finley, David A.; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter M.; Olmstead, Matthew D.; Schneider, Donald P.; Shapiro, Charles; Sollerman, Jesper

    2014-01-01

    Using a sample of 608 Type Ia supernovae from the SDSS-II and BOSS surveys, combined with a sample of foreground galaxies from SDSS-II, we estimate the weak lensing convergence for each supernova line of sight. We find that the correlation between this measurement and the Hubble residuals is consistent with the prediction from lensing (at a significance of 1.7σ). Strong correlations are also found between the residuals and supernova nuisance parameters after a linear correction is applied. When these other correlations are taken into account, the lensing signal is detected at 1.4σ. We show, for the first time, that distance estimates from supernovae can be improved when lensing is incorporated, by including a new parameter in the SALT2 methodology for determining distance moduli. The recovered value of the new parameter is consistent with the lensing prediction. Using cosmic microwave background data from WMAP7, H {sub 0} data from Hubble Space Telescope and Sloan Digital Sky Survey (SDSS) Baryon acoustic oscillations measurements, we find the best-fit value of the new lensing parameter and show that the central values and uncertainties on Ω {sub m} and w are unaffected. The lensing of supernovae, while only seen at marginal significance in this low-redshift sample, will be of vital importance for the next generation of surveys, such as DES and LSST, which will be systematics-dominated.

  8. Finding Galaxy Groups in the Fields of Lensed Quasars

    NASA Astrophysics Data System (ADS)

    Grant, Catherine E.; Bautz, M. W.

    2006-09-01

    Gravitationally lensed quasars can be used as an invaluable cosmological tool, however, the asymmetry observed in many lensed systems requires models of the lens to include a strong external shear component in addition to the lensing galaxy. The lensing galaxy may be a member of a group or cluster which could provide sufficient shear to account for the lensed image configuration. We are searching for X-ray emission from groups and clusters of galaxies in the fields of multiply-imaged quasars using Chandra's resolving power to separate the faint diffuse emission from the much brighter quasar images. We have analyzed all observations of gravitationally lensed quasars available in the Chandra archive from launch through the end of 2005 to search for this diffuse emission. We present a catalog of cluster and group properties for those fields with significant diffuse emission, and upper limits on group properties in fields where no diffuse emission is detected. These measurements are compared with optical data, where available, and with quasar lensing models. This research was supported by NASA contracts NAS-8-38252 and NAS-8-37716.

  9. Tolerancing panoramic lenses

    NASA Astrophysics Data System (ADS)

    Parent, Jocelyn; Thibault, Simon

    2009-08-01

    Tolerancing a lens is a basic procedure in lens design. It consists in first defining an appropriate set of tolerances for the lens, then in adding compensators with their allowable ranges and finally in selecting an appropriate quality criterion (MTF, RMS spot size, wavefront error, boresight error...) for the given application. The procedure is straightforward for standard optical systems. However, it becomes more complex when tolerancing very wide angle lenses (larger than 150 degrees). With a large field of view, issues such as severe off-axis pupil shift, considerable distortion and low relative illumination must be addressed. The pupil shift affects the raytrace as some rays can no longer be traced properly. For high resolution imagers, particularly for robotic and security applications, the image footprint is most critical in order to limit or avoid complex calibration procedures. We studied various wide angle lenses and concluded that most of the distortion comes from the front surface of the lens. Consequently, any variation of the front surface will greatly affect the image footprint. In this paper, we study the effects on the image footprint of slightly modifying the front surface of four different lenses: a simple double-gauss for comparison, a fisheye lens, a catadioptric system (omnidirectional lens) and a Panomorph lens. We also present a method to analyze variations of the image footprint. Our analysis shows that for wide angle lenses, on which the entrance pupil is much smaller than the front surface, irregularities (amplitude, slope and location) are critical on both aspherical and spherical front surfaces to predict the image footprint variation for high resolution cameras. Finally, we present how the entrance pupil varies (location, size) with the field of view for these optical systems.

  10. The HST Frontier Fields: Gravitational Lensing Models Release

    NASA Astrophysics Data System (ADS)

    Coe, Dan A.; Lotz, J.; Natarajan, P.; Richard, J.; Zitrin, A.; Kneib, J.; Ebeling, H.; Sharon, K.; Johnson, T.; Limousin, M.; Bradac, M.; Hoag, A.; Cain, B.; Merten, J.; Williams, L. L.; Sebesta, K.; Meneghetti, M.; Koekemoer, A. M.; Barker, E. A.

    2014-01-01

    The Hubble Frontier Fields (HFF) is a Director's Discretionary Time (DDT) program to deeply observe up to six massive strong-lensing galaxy clusters and six "blank" fields in parallel. These complementary observations will yield magnified and direct images of some of the most distant galaxies yet observed. The strongly lensed images will be our deepest views of our universe to date. Interpretation of some (but not all) observed properties of the strongly lensed galaxies requires gravitational lens modeling. In order to maximize the value of this public dataset to the extragalactic community, STScI commissioned five teams funded by NASA to derive the best possible lens models from existing data. After coordinating to share observational constraints, including measured redshifts of strongly lensed galaxies, the teams independently derived lens models using robust, established methodologies. STScI released these models to the community in October before HFF observations of the first cluster, Abell 2744. Here we describe these models as well as a web tool which allows users to extract magnification estimates with uncertainties from all models for any galaxy strongly lensed by a HFF cluster. Inputs are the galaxy's coordinates (RA and Dec), redshift, and (optionally) observed radius. We also discuss ongoing work to study lens model uncertainties by modeling simulated clusters.

  11. Fitting gravitational lenses: truth or delusion

    NASA Astrophysics Data System (ADS)

    Evans, N. Wyn; Witt, Hans J.

    2003-11-01

    The observables in a strong gravitational lens are usually just the image positions and sometimes the flux ratios. We develop a new and simple algorithm which allows a set of models to be fitted exactly to the observations. Taking our cue from the strong body of evidence that early-type galaxies are close to isothermal, we assume that the lens is scale-free with a flat rotation curve. External shear can be easily included. Our algorithm allows full flexibility regarding the angular structure of the lensing potential. Importantly, all the free parameters enter linearly into the model and so the lens and flux ratio equations can always be solved by straightforward matrix inversion. The models are only restricted by the fact that the surface mass density must be positive. We use this new algorithm to examine some of the claims made for anomalous flux ratios. It has been argued that such anomalies betray the presence of substantial amounts of substructure in the lensing galaxy. We demonstrate by explicit construction that some of the lens systems for which substructure has been claimed can be well fitted by smooth lens models. This is especially the case when the systematic errors in the flux ratios (caused by microlensing or differential extinction) are taken into account. However, there is certainly one system (B1422+231) for which the existing smooth models are definitely inadequate and for which substructure may be implicated. Within a few tens of kpc of the lensing galaxy centre, dynamical friction and tidal disruption are known to be very efficient at dissolving any substructure. Very little substructure is projected within the Einstein radius. The numbers of strong lenses for which substructure is currently being claimed may be so large that this contradicts rather than supports cold dark matter theories.

  12. Vertical and Horizontal Jump Tests Are Strongly Associated With Competitive Performance in 100-m Dash Events.

    PubMed

    Loturco, Irineu; Pereira, Lucas A; Cal Abad, Cesar C; DʼAngelo, Ricardo A; Fernandes, Victor; Kitamura, Katia; Kobal, Ronaldo; Nakamura, Fabio Y

    2015-07-01

    Fourteen male elite sprinters performed short-distance sprints and jump tests until 18 days before 100-m dash competitions in track and field to determine if these tests are associated with 100-m sprint times. Testing comprised of squat jumps (SJ), countermovement jumps (CMJ), horizontal jumps (HJ), maximum mean propulsive power relative to body mass in loaded jump squats, and a flying start 50-m sprint. Moderate associations were found between speed tests and competitive 100-m times (r = 0.54, r = 0.61, and r = 0.66 for 10-, 30-, and 50-m, respectively, p ≤ 0.05). In addition, the maximum mean propulsive power relative to body mass was very largely correlated with 100-m sprinting performance (r = 0.75, p < 0.01). The correlations of SJ, CMJ, and HJ with actual 100-m sprinting times amounted to -0.82, -0.85, and -0.81, respectively. Because of their practicality, safeness, and relationship with the actual times obtained by top-level athletes in 100-m dash events, it is highly recommended that SJ, CMJ, and HJ be regularly incorporated into elite sprint-testing routines. PMID:25627643

  13. Thermal lensing in optical fibers.

    PubMed

    Dong, Liang

    2016-08-22

    Average powers from fiber lasers have reached the point that a quantitative understanding of thermal lensing and its impact on transverse mode instability is becoming critical. Although thermal lensing is well known qualitatively, there is a general lack of a simple method for quantitative analysis. In this work, we first conduct a study of thermal lensing in optical fibers based on a perturbation technique. The perturbation technique becomes increasingly inaccurate as thermal lensing gets stronger. It, however, provides a basis for determining a normalization factor to use in a more accurate numerical study. A simple thermal lensing threshold condition is developed. The impact of thermal lensing on transverse mode instability is also studied. PMID:27557260

  14. A model for testing strong gravity via X-ray reflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Bambi, Cosimo; Nampalliwar, Sourabh; Cardenas-Avendano, Alejandro

    2016-07-01

    Astrophysical black hole candidates are thought to be the Kerr black holes of general relativity. However, a direct observational evidence is still lacking. The X-ray radiation produced in the inner part of the accretion disk can be a powerful tool to test the Kerr nature of these objects. In this talk, we present a new model for testing the Kerr black hole hypothesis via X-ray reflection spectroscopy. We employ the formalism of the transfer function proposed by Cunningham 40 years ago. The transfer function acts as an integration kernel and takes into account all the relativistic effects. We have developed a code to compute transfer functions in arbitrary stationary and axisymmetric spacetimes. These transfer functions are tabulated in FITS files and combined with XILLVER. The result is best model that we can have today for testing black hole candidates via X-ray reflection spectroscopy.

  15. A new weak lensing shear analysis method using ellipticity defined by 0th order moments

    NASA Astrophysics Data System (ADS)

    Okura, Yuki; Futamase, Toshifumi

    2015-04-01

    We developed a new method that uses ellipticity defined by 0th order moments (0th-ellipticity) for weak gravitational lensing shear analysis. Although there is a strong correlation between the ellipticity calculated using this approach and the usual ellipticity defined by the 2nd order moment, the ellipticity calculated here has a higher signal-to-noise ratio because it is weighted to the central region of the image. These results were confirmed using data for Abell 1689 from the Subaru telescope. For shear analysis, we adopted the ellipticity of re-smeared artificial image method for point spread function correction, and we tested the precision of this 0th-ellipticity with simple simulation, then we obtained the same level of precision with the results of ellipticity defined by quadrupole moments. Thus, we can expect that weak lensing analysis using 0 shear will be improved in proportion to the statistical error.

  16. A Brief Test of the Tokyo Sokushin VSE-355G3 Strong Motion Velocity Seismometer

    USGS Publications Warehouse

    Hutt, Charles R.; Evans, John R.; Yokoi, Isamu

    2008-01-01

    The VSE-355G3 seismometer is a broadband seismometer (called a 'servo velocity meter' by Tokyo Sokushin) with a specified clip level of 2 m/s and a flat response to earth velocity from 0.008 Hertz (Hz) to 70 Hz. Mr. Yokoi and Mr. Kurahashi of Tokyo Sokushin shipped one instrument to the U. S. Geological Survey's Albuquerque Seismological Laboratory (ASL) for testing in early September 2007. They gave a presentation on this instrument and some of their other products to the authors and others on September 6, 2007. Testing of the VSE-355G3, Serial Number 70520, commenced on Friday, September 7, 2007.

  17. Lensing of 21-cm fluctuations by primordial gravitational waves.

    PubMed

    Book, Laura; Kamionkowski, Marc; Schmidt, Fabian

    2012-05-25

    Weak-gravitational-lensing distortions to the intensity pattern of 21-cm radiation from the dark ages can be decomposed geometrically into curl and curl-free components. Lensing by primordial gravitational waves induces a curl component, while the contribution from lensing by density fluctuations is strongly suppressed. Angular fluctuations in the 21-cm background extend to very small angular scales, and measurements at different frequencies probe different shells in redshift space. There is thus a huge trove of information with which to reconstruct the curl component of the lensing field, allowing tensor-to-scalar ratios conceivably as small as r~10(-9)-far smaller than those currently accessible-to be probed. PMID:23003237

  18. Lensing of 21-cm Fluctuations by Primordial Gravitational Waves

    NASA Astrophysics Data System (ADS)

    Book, Laura; Kamionkowski, Marc; Schmidt, Fabian

    2012-05-01

    Weak-gravitational-lensing distortions to the intensity pattern of 21-cm radiation from the dark ages can be decomposed geometrically into curl and curl-free components. Lensing by primordial gravitational waves induces a curl component, while the contribution from lensing by density fluctuations is strongly suppressed. Angular fluctuations in the 21-cm background extend to very small angular scales, and measurements at different frequencies probe different shells in redshift space. There is thus a huge trove of information with which to reconstruct the curl component of the lensing field, allowing tensor-to-scalar ratios conceivably as small as r˜10-9—far smaller than those currently accessible—to be probed.

  19. Omni-focal refractive focus correction technology as a substitute for bi/multi-focal intraocular lenses, contact lenses, and spectacles

    NASA Astrophysics Data System (ADS)

    Ben Yaish, Shai; Zlotnik, Alex; Raveh, Ido; Yehezkel, Oren; Belkin, Michael; Lahav, Karen; Zalevsky, Zeev

    2009-02-01

    We present novel technology for extension in depth of focus of imaging lenses for use in ophthalmic lenses correcting myopia, hyperopia with regular/irregular astigmatism and presbyopia. This technology produces continuous focus without appreciable loss of energy. It is incorporated as a coating or engraving on the surface for spectacles, contact or intraocular lenses. It was fabricated and tested in simulations and in clinical trials. From the various testing this technology seems to provide a satisfactory single-lens solution. Obtained performance is apparently better than those of existing multi/bifocal lenses and it is modular enough to provide solution to various ophthalmic applications.

  20. SUNGLASS: A Weak-lensing Simulation Pipeline

    NASA Astrophysics Data System (ADS)

    Kiessling, Alina; Taylor, A.; Heavens, A.; Rhodes, J.; Bartlett, J.

    2013-01-01

    Weak gravitational lensing analysis is a powerful tool to investigate the dark Universe. Next generation weak-lensing telescope surveys (e.g. Euclid and WFIRST) promise to determine the equation of state of dark energy to 1% as well as probing the possibilities of extra dimensional gravity models and alternative cosmologies. To realize the potential of these new telescope surveys and to test new weak-lensing analysis techniques, challenges must be met. To achieve the small statistical errors required, experiments require full end-to-end simulations of huge volumes, which also probe the non-linear regime to assist in understanding the limitations of the analysis techniques. We have developed a new cosmic shear analysis pipeline SUNGLASS (Simulated UNiverses for Gravitational Lensing Analysis and Shear Surveys) that rapidly generates cosmic shear and convergence catalogues using N-body simulations. In this poster, I introduce the SUNGLASS pipeline and show how the SUNGLASS mock shear catalogues can be used in preparation for upcoming telescope missions and for analysis of existing observational data sets.

  1. High resolution weak lensing mass mapping combining shear and flexion

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Starck, J.-L.; Leonard, A.; Pires, S.

    2016-06-01

    Aims: We propose a new mass mapping algorithm, specifically designed to recover small-scale information from a combination of gravitational shear and flexion. Including flexion allows us to supplement the shear on small scales in order to increase the sensitivity to substructures and the overall resolution of the convergence map without relying on strong lensing constraints. Methods: To preserve all available small scale information, we avoid any binning of the irregularly sampled input shear and flexion fields and treat the mass mapping problem as a general ill-posed inverse problem, which is regularised using a robust multi-scale wavelet sparsity prior. The resulting algorithm incorporates redshift, reduced shear, and reduced flexion measurements for individual galaxies and is made highly efficient by the use of fast Fourier estimators. Results: We tested our reconstruction method on a set of realistic weak lensing simulations corresponding to typical HST/ACS cluster observations and demonstrate our ability to recover substructures with the inclusion of flexion, which are otherwise lost if only shear information is used. In particular, we can detect substructures on the 15'' scale well outside of the critical region of the clusters. In addition, flexion also helps to constrain the shape of the central regions of the main dark matter halos. Our mass mapping software, called Glimpse2D, is made freely available at http://www.cosmostat.org/software/glimpse

  2. Testing the strong equivalence principle with the triple pulsar PSR J 0337 +1715

    NASA Astrophysics Data System (ADS)

    Shao, Lijing

    2016-04-01

    Three conceptually different masses appear in equations of motion for objects under gravity, namely, the inertial mass, mI , the passive gravitational mass, mP, and the active gravitational mass, mA. It is assumed that, for any objects, mI=mP=mA in the Newtonian gravity, and mI=mP in the Einsteinian gravity, oblivious to objects' sophisticated internal structure. Empirical examination of the equivalence probes deep into gravity theories. We study the possibility of carrying out new tests based on pulsar timing of the stellar triple system, PSR J 0337 +1715 . Various machine-precision three-body simulations are performed, from which, the equivalence-violating parameters are extracted with Markov chain Monte Carlo sampling that takes full correlations into account. We show that the difference in masses could be probed to 3 ×1 0-8 , improving the current constraints from lunar laser ranging on the post-Newtonian parameters that govern violations of mP=mI and mA=mP by thousands and millions, respectively. The test of mP=mA would represent the first test of Newton's third law with compact objects.

  3. Testing the case for the creation of a strongly interacting quark gluon plasma at RHIC

    NASA Astrophysics Data System (ADS)

    Adil, Azfar

    Recent data from the Relativistic Heavy Ion Collider (RHIC) has provided information regarding the creation of dense QCD matter in Heavy Ion Collisions (HIC). Two of the most puzzling issues raised are; (1) models using ideal hydrodynamics to describe bulk evolution have met with great success in reproducing data in HIC at RHIC, and (2) the recent data detailing the production of non-photonic electrons from heavy meson decays has shown a large quenching of heavy quark jets that is not explained by radiative energy loss calculations. These two surprising results lend credence to the claim that a Strongly Coupled Quark Gluon Plasma (sQGP) has been created at RHIC; with the strong coupling characteristics providing both the low viscosity needed by (1) and the large momentum transfers needed by (2). In order to properly quantify this, one needs to get a better understanding of the detailes of jet tomography so that one can truly adjudicate the need for sQGP creation. We consider the theoretical uncertainties stemming from the Poisson convolution assumption in energy loss calculations. We examine two different ways to account for the leakage of probabilities into unphysical regions and show that the evolution of the nuclear modification factor, RAA, with center of mass energy is sensitive to these differences. The success of ideal hydrodynamics in describing the evolution of bulk matter in the QGP phase is dependent on the choice of initial state that is fed into the evolution equations. The Participant Brodsk-Gunion-Kuhn initial conditions lead to a good agreement with the data while initial states inspired by Color Glass Condensate (CGC) models overestimate the data and seem to imply the need for viscous dissipative corrections to the dynamics. We propose 3D jet tomography as a probe to experimentally differentiate between the BGK and CGC initial state models. We find and induced non zero directed flow vl in the high p⊥ spectra in both BGK and CGC models that can be

  4. A preliminary improved test of the flavor independence of strong interactions

    SciTech Connect

    Abe, K.; Abe, K.; Akagi, T.; SLD Collaboration

    1997-06-01

    The authors present an improved comparison of the strong couplings of gluons to light (u, d, and s), c, and b quarks, determined from multijet rates in flavor-tagged samples of hadronic Z{sup 0} decays recorded with the SLC Large Detector at the SLAC Linear Collider between 1993 and 1995. Flavor separation on the basis of lifetime and decay multiplicity differences among hadrons containing light, c, and b quarks was made using the SLD precision tracking system, yielding tags with high purity and low bias against {ge} 3-jet final states. They find: {alpha}{sub s}{sup uds}/{alpha}{sub s}{sup all} = 0.997 {+-} 0.011(stat) {+-} 0.011(syst) {+-} 0.005(theory), {alpha}{sub s}{sup c}/{alpha}{sub s}{sup all} = 0.984 {+-} 0.042 {+-} 0.053 {+-} 0.022, {alpha}{sub s}{sup b}/{alpha}{sub s}{sup all} = 1.022 {+-} 0.019 {+-} 0.023 {+-} 0.012.

  5. Interferometric Plasmonic Lensing with Nanohole Arrays

    SciTech Connect

    Gong, Yu; Joly, Alan G.; El-Khoury, Patrick Z.; Hess, Wayne P.

    2014-12-18

    Nonlinear photoemission electron microscopy (PEEM) of nanohole arrays in gold films maps propagating surface plasmons (PSPs) launched from lithographically patterned structures. Strong near field photoemission patterns are observed in the PEEM images, recorded following low angle of incidence irradiation of nanohole arrays with sub-15 fs laser pulses centered at 780 nm. The recorded photoemission patterns are attributed to constructive and destructive interferences between PSPs launched from the individual nanoholes which comprise the array. By exploiting the wave nature of PSPs, we demonstrate how varying the array geometry (hole diameter, pitch, and number of rows/columns) ultimately yields intense localized photoemission. Through a combination of PEEM and finite-difference time-domain simulations, we identify the optimal array geometry for efficient light coupling and interferometric plasmonic lensing. We show a preliminary application of inteferometric plasmonic lensing by enhancing the photoemission from the vertex of a gold triangle using nanohole array.

  6. Surface morphology of contact lenses probed with microscopy techniques.

    PubMed

    Guryca, Vilém; Hobzová, Radka; Prádný, Martin; Sirc, Jakub; Michálek, Jirí

    2007-09-01

    The present study is bringing a comparison of surface morphology for various types of contact lenses. A novel method--scanning electron microscopy under aqueous conditions (cryo-SEM)--was tested for visualization of lenses at magnifications up to 2000x. For imaging lens surface on nanometre scale, we employed atomic force microscopy (AFM) in aqueous media. Various materials of lenses, based on silicone hydrogels or conventional hydrogels, were investigated. Total, 10 types of contact lenses from five manufacturers were selected and probed. We found that different methods of lens manufacture (lathe-cutting, cast-moulding, and spin casting) led to different values of surface roughness. In the swollen state, roughness values of lens surfaces lie between 4 and 140 nm. Lenses manufactured by lathe-cutting exhibit notable higher values, so that they could be easily distinguished from others. In cast-moulded lenses, the surface roughness decreased with increasing water content. Moreover, additional treatments of lenses introduced unique structural motifs onto surface. For instance, porous structure was found on lens surface finalized with plasma oxidation. PMID:17507281

  7. Variable practice with lenses improves visuo-motor plasticity

    NASA Technical Reports Server (NTRS)

    Roller, C. A.; Cohen, H. S.; Kimball, K. T.; Bloomberg, J. J.

    2001-01-01

    Novel sensorimotor situations present a unique challenge to an individual's adaptive ability. Using the simple and easily measured paradigm of visual-motor rearrangement created by the use of visual displacement lenses, we sought to determine whether an individual's ability to adapt to visuo-motor discordance could be improved through training. Subjects threw small balls at a stationary target during a 3-week practice regimen involving repeated exposure to one set of lenses in block practice (x 2.0 magnifying lenses), multiple sets of lenses in variable practice (x 2.0 magnifying, x 0.5 minifying and up-down reversing lenses) or sham lenses. At the end of training, adaptation to a novel visuo-motor situation (20-degree right shift lenses) was tested. We found that (1) training with variable practice can increase adaptability to a novel visuo-motor situation, (2) increased adaptability is retained for at least 1 month and is transferable to further novel visuo-motor permutations and (3) variable practice improves performance of a simple motor task even in the undisturbed state. These results have implications for the design of clinical rehabilitation programs and countermeasures to enhance astronaut adaptability, facilitating adaptive transitions between gravitational environments.

  8. Lotung large-scale seismic test strong motion records. Volume 1, General description: Final report

    SciTech Connect

    Not Available

    1992-03-01

    The Electric Power Research Institute (EPRI), in cooperation with the Taiwan Power Company (TPC), constructed two models (1/4 scale and 1/12 scale) of a nuclear plant concrete containment structure at a seismically active site in Lotung, Taiwan. Extensive instrumentation was deployed to record both structural and ground responses during earthquakes. The experiment, generally referred to as the Lotung Large-Scale Seismic Test (LSST), was used to gather data for soil-structure interaction (SSI) analysis method evaluation and validation as well as for site ground response investigation. A number of earthquakes having local magnitudes ranging from 4.5 to 7.0 have been recorded at the LSST site since the completion of the test facility in September 1985. This report documents the earthquake data, both raw and processed, collected from the LSST experiment. Volume 1 of the report provides general information on site location, instrument types and layout, data acquisition and processing, and data file organization. The recorded data are described chronologically in subsequent volumes of the report.

  9. RHIC electron lenses upgrades

    SciTech Connect

    Gu, X.; Altinbas, Z.; Bruno, D.; Binello, S.; Costanzo, M.; Drees, A.; Fischer, W.; Gassner, D. M.; Hock, J.; Hock, K.; Harvey, M.; Luo, Y.; Marusic, A.; Mi, C.; Mernick, K.; Minty, M.; Michnoff, R.; Miller, T. A.; Pikin, A. I.; Robert-Demolaize, G.; Samms, T.; Shrey, T. C.; Schoefer, V.; Tan, Y.; Than, R.; Thieberger, P.; White, S. M.

    2015-05-03

    In the Relativistic Heavy Ion Collider (RHIC) 100 GeV polarized proton run in 2015, two electron lenses were used to partially compensate for the head-on beam-beam effect for the first time. Here, we describe the design of the current electron lens, detailing the hardware modifications made after the 2014 commissioning run with heavy ions. A new electron gun with 15-mm diameter cathode is characterized. The electron beam transverse profile was measured using a YAG screen and fitted with a Gaussian distribution. During operation, the overlap of the electron and proton beams was achieved using the electron backscattering detector in conjunction with an automated orbit control program.

  10. Three gravitationally lensed supernovae behind clash galaxy clusters

    SciTech Connect

    Patel, Brandon; McCully, Curtis; Jha, Saurabh W.; Holoien, Thomas W.-S.; Rodney, Steven A.; Jones, David O.; Graur, Or; Riess, Adam G.; Merten, Julian; Zitrin, Adi; Matheson, Thomas; Sako, Masao; Postman, Marc; Coe, Dan; Bradley, Larry; Bartelmann, Matthias; Balestra, Italo; Benítez, Narciso; Bouwens, Rychard; Broadhurst, Tom; and others

    2014-05-01

    We report observations of three gravitationally lensed supernovae (SNe) in the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program. These objects, SN CLO12Car (z = 1.28), SN CLN12Did (z = 0.85), and SN CLA11Tib (z = 1.14), are located behind three different clusters, MACSJ1720.2+3536 (z = 0.391), RXJ1532.9+3021 (z = 0.345), and A383 (z = 0.187), respectively. Each SN was detected in Hubble Space Telescope optical and infrared images. Based on photometric classification, we find that SNe CLO12Car and CLN12Did are likely to be Type Ia supernovae (SNe Ia), while the classification of SN CLA11Tib is inconclusive. Using multi-color light-curve fits to determine a standardized SN Ia luminosity distance, we infer that SN CLO12Car was ∼1.0 ± 0.2 mag brighter than field SNe Ia at a similar redshift and ascribe this to gravitational lens magnification. Similarly, SN CLN12Did is ∼0.2 ± 0.2 mag brighter than field SNe Ia. We derive independent estimates of the predicted magnification from CLASH strong+weak-lensing maps of the clusters (in magnitude units, 2.5 log{sub 10}μ): 0.83 ± 0.16 mag for SN CLO12Car, 0.28 ± 0.08 mag for SN CLN12Did, and 0.43 ± 0.11 mag for SN CLA11Tib. The two SNe Ia provide a new test of the cluster lens model predictions: we find that the magnifications based on the SN Ia brightness and those predicted by the lens maps are consistent. Our results herald the promise of future observations of samples of cluster-lensed SNe Ia (from the ground or space) to help illuminate the dark-matter distribution in clusters of galaxies, through the direct determination of absolute magnifications.

  11. Where the world stands still: turnaround as a strong test of ΛCDM cosmology

    SciTech Connect

    Pavlidou, V.; Tomaras, T.N. E-mail: tomaras@physics.uoc.gr

    2014-09-01

    Our intuitive understanding of cosmic structure formation works best in scales small enough so that isolated, bound, relaxed gravitating systems are no longer adjusting their radius; and large enough so that space and matter follow the average expansion of the Universe. Yet one of the most robust predictions of ΛCDM cosmology concerns the scale that separates these limits: the turnaround radius, which is the non-expanding shell furthest away from the center of a bound structure. We show that the maximum possible value of the turnaround radius within the framework of the ΛCDM model is, for a given mass M, equal to (3GM/Λ c{sup 2}){sup 1/3}, with G Newton's constant and c the speed of light, independently of cosmic epoch, exact nature of dark matter, or baryonic effects. We discuss the possible use of this prediction as an observational test for ΛCDM cosmology. Current data appear to favor ΛCDM over alternatives with local inhomogeneities and no Λ. However there exist several local-universe structures that have, within errors, reached their limiting size. With improved determinations of their turnaround radii and the enclosed mass, these objects may challenge the limit and ΛCDM cosmology.

  12. Strong violations of locality by testing Bell’s inequality with improved entangled-photon systems

    NASA Astrophysics Data System (ADS)

    Wang, Yao; Fan, Dai-He; Guo, Wei-Jie; Wei, Lian-Fu

    2015-08-01

    Bell’s theorem states that quantum mechanics cannot be accounted for by any local theory. One of the examples is the existence of quantum non-locality is essentially violated by the local Bell’s inequality. Therefore, the violation of Bell’s inequality (BI) has been regarded as one of the robust evidences of quantum mechanics. Until now, BI has been tested by many experiments, but the maximal violation (i.e., Cirel’son limit) has never been achieved. By improving the design of entangled sources and optimizing the measurement settings, in this work we report the stronger violations of the Clauser-Horne-Shimony-Holt (CHSH)-type Bell’s inequality. The biggest value of Bell’s function in our experiment reaches to a significant one: S = 2.772± 0.063, approaching to the so-called Cirel’son limit in which the Bell function value is . Further improvement is possible by optimizing the entangled-photon sources. Project supported by the National Natural Science Foundation of China (Grant Nos. 61308008, 91321104, U1330201, and 11174373) and the Fundamental Research Funds for the Central Universities (Grant No. 2682014CX081).

  13. Optics of progressive addition lenses.

    PubMed

    Sheedy, J E; Buri, M; Bailey, I L; Azus, J; Borish, I M

    1987-02-01

    The optical characteristics of the major progressive addition lenses were measured using an automated lensometer with a specially designed lens holder to simulate eye rotation. Measurements were made every 3 degrees (about 1.5 mm) and graphs of isospherical equivalent lines and isocylinder lines were developed. Generally the near zone of these lenses is narrower and lower than in bifocal or trifocal lenses. Distinct differences exist between the various progressive lenses. The width of the near zone, rate of power progression, amount of unwanted cylinder (level with the distance center), and clarity of the distance zone are compared for the various lenses. The optical measurements demonstrate an apparent trade-off between the size of the cylinder-free area of the lens and the amount of the cylinder. PMID:3826294

  14. Cross-correlation of Planck CMB lensing and CFHTLenS galaxy weak lensing maps

    NASA Astrophysics Data System (ADS)

    Liu, Jia; Hill, J. Colin

    2015-09-01

    We cross-correlate cosmic microwave background (CMB) lensing and galaxy weak lensing maps using the Planck 2013 and 2015 data and the 154 deg2 Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). This measurement probes large-scale structure at intermediate redshifts ≈0.9 , between the high- and low-redshift peaks of the CMB and CFHTLenS lensing kernels, respectively. Using the noise properties of these data sets and standard Planck 2015 Λ CDM cosmological parameters, we forecast a signal-to-noise ratio ≈4.6 for the cross-correlation. We find that the noise level of our actual measurement agrees well with this estimate, but the amplitude of the signal lies well below the theoretical prediction. The best-fit amplitudes of our measured cross-correlations are A2013=0.48 ±0.26 and A2015=0.44 ±0.22 , using the 2013 and 2015 Planck CMB lensing maps, respectively, where A =1 corresponds to the fiducial Planck 2015 Λ CDM prediction. Due to the low measured amplitude, the detection significance is moderate (≈2 σ ) and the data are in tension with the theoretical prediction (≈2 - 2.5 σ ) . The tension is reduced somewhat when compared to predictions using WMAP9 parameters, for which we find A2013=0.56 ±0.30 and A2015=0.52 ±0.26 . We consider various systematic effects, finding that photometric redshift uncertainties, contamination by intrinsic alignments, and effects due to the masking of galaxy clusters in the Planck 2015 CMB lensing reconstruction are able to help resolve the tension at a significant level (≈10 % each). An overall multiplicative bias in the CFHTLenS shear data could also play a role, which can be tested with existing data. We close with forecasts for measurements of the CMB lensing—galaxy lensing cross-correlation using ongoing and future weak lensing surveys, which will definitively test the significance of the tension in our results with respect to Λ CDM .

  15. THE DISTRIBUTION OF DARK MATTER OVER THREE DECADES IN RADIUS IN THE LENSING CLUSTER ABELL 611

    SciTech Connect

    Newman, Andrew B.; Ellis, Richard S.; Treu, Tommaso; Marshall, Philip J.; Sand, David J.; Richard, Johan; Capak, Peter; Miyazaki, Satoshi

    2009-12-01

    We present a detailed analysis of the baryonic and dark matter distribution in the lensing cluster Abell 611 (z = 0.288), with the goal of determining the dark matter profile over an unprecedented range of cluster-centric distance. By combining three complementary probes of the mass distribution, weak lensing from multi-color Subaru imaging, strong lensing constraints based on the identification of multiply imaged sources in Hubble Space Telescope images, and resolved stellar velocity dispersion measures for the brightest cluster galaxy secured using the Keck telescope, we extend the methodology for separating the dark and baryonic mass components introduced by Sand et al. Our resulting dark matter profile samples the cluster from approx3 kpc to 3.25 Mpc, thereby providing an excellent basis for comparisons with recent numerical models. We demonstrate that only by combining our three observational techniques can degeneracies in constraining the form of the dark matter profile be broken on scales crucial for detailed comparisons with numerical simulations. Our analysis reveals that a simple Navarro-Frenk-White (NFW) profile is an unacceptable fit to our data. We confirm earlier claims based on less extensive analyses of other clusters that the inner profile of the dark matter profile deviates significantly from the NFW form and find a inner logarithmic slope beta flatter than 0.3 (68%; where rho{sub DM} propor to r{sup -b}eta at small radii). In order to reconcile our data with cluster formation in a LAMBDACDM cosmology, we speculate that it may be necessary to revise our understanding of the nature of baryon-dark matter interactions in cluster cores. Comprehensive weak and strong lensing data, when coupled with kinematic information on the brightest cluster galaxy, can readily be applied to a larger sample of clusters to test the universality of these results.

  16. LENSING NOISE IN MILLIMETER-WAVE GALAXY CLUSTER SURVEYS

    SciTech Connect

    Hezaveh, Yashar; Vanderlinde, Keith; Holder, Gilbert; De Haan, Tijmen

    2013-08-01

    We study the effects of gravitational lensing by galaxy clusters of the background of dusty star-forming galaxies (DSFGs) and the cosmic microwave background (CMB), and examine the implications for Sunyaev-Zel'dovich-based (SZ) galaxy cluster surveys. At the locations of galaxy clusters, gravitational lensing modifies the probability distribution of the background flux of the DSFGs as well as the CMB. We find that, in the case of a single-frequency 150 GHz survey, lensing of DSFGs leads both to a slight increase ({approx}10%) in detected cluster number counts (due to a {approx}50% increase in the variance of the DSFG background, and hence an increased Eddington bias) and a rare (occurring in {approx}2% of clusters) 'filling-in' of SZ cluster signals by bright strongly lensed background sources. Lensing of the CMB leads to a {approx}55% reduction in CMB power at the location of massive galaxy clusters in a spatially matched single-frequency filter, leading to a net decrease in detected cluster number counts. We find that the increase in DSFG power and decrease in CMB power due to lensing at cluster locations largely cancel, such that the net effect on cluster number counts for current SZ surveys is subdominant to Poisson errors.

  17. Gravitational lensing in observational cosmology

    NASA Astrophysics Data System (ADS)

    Nottale, L.

    amplification of Brightest Cluster Galaxies by foreground clusters are analysed, including the discussion of a selection effect precisely due to gravitational luminosity amplification. It results in an artificial increase of the deceleration parameter of the Universe measured from the Hubble diagram of these objects. We recall our proposal that the sample of distant 3C radiogalaxies of redshift > 1 is strongly perturbed by lensing effects, mostly by foreground clusters of galaxies (i.e. only the luminosity is changed without image multiplication), but also for some objects by galaxies, producing gravitational mirages. The case of 3C324, for which definite evidence for multiple imaging has been recently obtained, is described, including detailed modelling of the lensing configuration. We present a highly significant statistical effect of lensing on absorption line QSOs due to matter lying at the absorption redshifts. Microlensing is also considered, and we recall our recent proposal that the variability of some among the OVV QSOs turning to BL Lac at maximum brightness, like the eruptive object 0846 +51W1, is a consequence of microlensing by stars or compact objects constituting foreground galaxy halos. Finally, discrepant redshift associations are considered. We recall how the case of anomalous quintets of galaxies have been explained by the gravitational lensing effects of quartets halos on background galaxies. Then we present evidence that the Arp QSO-galaxy associations may be the result of the combined lensing effects of several superposed galaxies, groups and clusters. Cet article présente une revue de certains résultats théoriques et observationnels concernant les divers effets de lentille gravitationnelle, complétée par des résultats nouveaux non encore publiés. Dans la partie théorique, nous considérons essentiellement l'approche relativiste employant les équations scalaires optiques. La forme de ces équations est rappelée : elles relient les diverses d

  18. Focusing Kinoform Lenses: Optical Design and Experimental Validation

    SciTech Connect

    Alianelli, Lucia; Sawhney, Kawal J. S.; Snigireva, Irina; Snigirev, Anatoly

    2010-06-23

    X-ray focusing lenses with a kinoform profile are high brilliance optics that can produce nano-sized beams on 3rd generation synchrotron beamlines. The lenses are fabricated with sidewalls of micrometer lateral size. They are virtually non-absorbing and therefore can deliver a high flux over a good aperture. We are developing silicon and germanium lenses that will focus hard x-ray beams to less than 0.5 {mu}m size using a single refractive element. In this contribution, we present preliminary optical design and experimental test carried out on ID06 ESRF: the lenses were used to image directly the undulator source, providing a beam with fwhm of about 0.7 {mu}m.

  19. New insights into peculiar thermonuclear supernovae and line of sight effects in gravitational lensing

    NASA Astrophysics Data System (ADS)

    McCully, Curtis

    Type Ia supernovae (SNe Ia) and gravitational lensing are important cosmological probes, but both are limited by theoretical, systematic uncertainties. One key uncertainty in distances derived using SNe Ia is our lack of understanding of the explosion mechanism for normal SNe Ia. We have studied peculiar type Iax supernovae that appear to be related to normal SNe Ia with the goal of understanding white dwarf explosions as a whole. In Chapter 2, using late-time Hubble Space Telescope (HST) observations of SN 2008A and SN 2005hk, both prototypical SNe Iax, we argue that these objects are pure deflagration explosions that do not unbind the white dwarf. In Chapter 3, we present observations of the type Iax SN 2012Z, one of the nearest ever discovered. Fortunately for us, its host galaxy, NGC 1309, was observed extensively with HST/ACS (to measure a Cepheid distance), giving us incredibly deep pre-explosion images of the site of SN 2012Z. We find that there is a source coincident with the position of the SN. We argue that the source is likely a helium star companion to the white dwarf that exploded. In galaxy-scale gravitational lenses, one of the largest systematic uncertainties arises due to other mass in the environment of the lens or along the line of sight (LOS). In Chapter 4, we develop an analytic framework to account for LOS effects. Our framework employs a hybrid approach treating a few perturbing galaxies as strong lenses, making it accurate, while treating the rest in the weak lensing approximation, making it also computationally efficient. In Chapter 5, we test our framework using simulations of realistic mass models. We suggest a method to characterize the strength of the LOS effects allowing us to systematically test when the weak lensing approximation is valid. We show that LOS effects are not equivalent to a single shear, but these non-linear effects are correctly captured by our framework. Our new methodology can be used to constrain cosmological

  20. Solid explosive plane-wave lenses pressed-to-shape with dies

    SciTech Connect

    Olinger, B.

    2007-11-01

    Solid-explosive plane-wave lenses 1", 2" and 4¼" in diameter have been mass-produced from components pressed-to-shape with aluminum dies. The method used to calculate the contour between the solid plane-wave lens components pressed-to-shape with the dies is explained. The steps taken to press, machine, and assemble the lenses are described. The method of testing the lenses, the results of those tests, and the corrections to the dies are reviewed. The work on the ½", 8", and 12" diameter lenses is also discussed.

  1. QUANTIFYING THE BIASES OF SPECTROSCOPICALLY SELECTED GRAVITATIONAL LENSES

    SciTech Connect

    Arneson, Ryan A.; Brownstein, Joel R.; Bolton, Adam S. E-mail: joelbrownstein@astro.utah.edu

    2012-07-01

    Spectroscopic selection has been the most productive technique for the selection of galaxy-scale strong gravitational lens systems with known redshifts. Statistically significant samples of strong lenses provide a powerful method for measuring the mass-density parameters of the lensing population, but results can only be generalized to the parent population if the lensing selection biases are sufficiently understood. We perform controlled Monte Carlo simulations of spectroscopic lens surveys in order to quantify the bias of lenses relative to parent galaxies in velocity dispersion, mass axis ratio, and mass-density profile. For parameters typical of the SLACS and BELLS surveys, we find (1) no significant mass axis ratio detection bias of lenses relative to parent galaxies; (2) a very small detection bias toward shallow mass-density profiles, which is likely negligible compared to other sources of uncertainty in this parameter; (3) a detection bias toward smaller Einstein radius for systems drawn from parent populations with group- and cluster-scale lensing masses; and (4) a lens-modeling bias toward larger velocity dispersions for systems drawn from parent samples with sub-arcsecond mean Einstein radii. This last finding indicates that the incorporation of velocity-dispersion upper limits of non-lenses is an important ingredient for unbiased analyses of spectroscopically selected lens samples. In general, we find that the completeness of spectroscopic lens surveys in the plane of Einstein radius and mass-density profile power-law index is quite uniform, up to a sharp drop in the region of large Einstein radius and steep mass-density profile, and hence that such surveys are ideally suited to the study of massive field galaxies.

  2. Lenses for JWST

    NASA Astrophysics Data System (ADS)

    Ebeling, Harald; Richard, Johan; Kneib, Jean-Paul; Repp, Andrew; Atek, Hakim; Egami, Eiichi; Windhorst, Rogier; Edge, Alastair

    2016-08-01

    JWST will dramatically advance our knowledge and understanding of the first generations of galaxies at z>10, their role in the re-ionization of the Universe, and the evolutionary processes that gave rise to the complexity and diversity of galaxies at the current epoch. As demonstrated by HST legacy projects like CLASH and the Hubble Frontier Fields, gravitational amplification by massive galaxy clusters can significantly extend the depth of the required observations. However, for JWST, reducing any diffuse background light will be just as crucial. We here propose Spitzer/IRAC observations of six massive cluster lenses, specifically selected as candidates for observation with JWST. By (a) quantifying the amount of intra-cluster light and (b) enabling us to improve our current lens models, the data resulting from the requested observations will be instrumental for the final selection of cluster targets that maximize the scientific returns of deep JWST observations.

  3. Gravitational lensing by gravastars

    NASA Astrophysics Data System (ADS)

    Kubo, Tomohiro; Sakai, Nobuyuki

    2016-04-01

    As a possible method to detect gravastars (gravitational-vacuum-star), which was originally proposed by Mazur and Mottola, we study their gravitational lensing effects. Specifically, we adopt a spherical thin-shell model of a gravastar developed by Visser and Wiltshire, which connects interior de Sitter geometry and exterior Schwarzschild geometry, and assume that its surface is optically transparent. We calculate the image of a companion which rotates around the gravastar; we find that some characteristic images appear, depending on whether the gravastar possess unstable circular orbits of photons (Model 1) or not (Model 2). For Model 2, we calculate the total luminosity change, which is called microlensing effects; the maximal luminosity could be considerably larger than the black hole with the same mass.

  4. Astrophysical observations: lensing and eclipsing Einstein's theories.

    PubMed

    Bennett, Charles L

    2005-02-11

    Albert Einstein postulated the equivalence of energy and mass, developed the theory of special relativity, explained the photoelectric effect, and described Brownian motion in five papers, all published in 1905, 100 years ago. With these papers, Einstein provided the framework for understanding modern astrophysical phenomena. Conversely, astrophysical observations provide one of the most effective means for testing Einstein's theories. Here, I review astrophysical advances precipitated by Einstein's insights, including gravitational redshifts, gravitational lensing, gravitational waves, the Lense-Thirring effect, and modern cosmology. A complete understanding of cosmology, from the earliest moments to the ultimate fate of the universe, will require developments in physics beyond Einstein, to a unified theory of gravity and quantum physics. PMID:15705841

  5. Equatorial potassium currents in lenses.

    PubMed

    Wind, B E; Walsh, S; Patterson, J W

    1988-02-01

    Earlier work with the vibrating probe demonstrated the existence of outward potassium currents at the equator and inward sodium currents at the optical poles of the lens. By adding microelectrodes to the system, it is possible to relate steady currents (J) to the potential difference (PD) measured with a microelectrode. By injecting an outward current (I), it is possible to determine resistances and also the PD at which the steady outward potassium current becomes zero (PDJ = 0). At this PD the concentration gradient for potassium efflux and the electrical gradient for potassium influx are balanced so that there is no net flow of potassium across the membranes associated with the production of J. The PDJ = 0 for 18 rat lenses was 86 mV and that for 12 frogs lenses was -95 mV. This agrees with the potassium equilibrium potential and provides strong evidence to support the view that the outward equatorial current, J, is a potassium current. With the injection of outward current, I, the PD becomes more negative, the outward equatorial current, J, decreases, and the inward current at the optical poles increases. This suggests that there are separate electrical loops for K+ and Na+ that are partially linked by the Na, K-pump. Using Ohm's law, it is possible to calculate the input resistance (R = delta PD/I), the resistance related to the production of J (RJ = delta PD/delta J), and the effect of the combined resistances (delta J/I). The driving force for J can be estimated (PDJ = 0-PD). The relationships among currents, voltages and resistance can be used to determine the characteristics of the membranes that are associated with the outward potassium current observed at the equator. The effects of graded deformation of the lens were determined. The effects were reversible. The sites of inward and outward currents were not altered. Following deformation, the equatorial current, J, increased, and the PD became less negative. The PDJ = 0 remains the same so the ratio of K

  6. Gravitational lensing by self-dual black holes in loop quantum gravity

    NASA Astrophysics Data System (ADS)

    Sahu, Satyabrata; Lochan, Kinjalk; Narasimha, D.

    2015-03-01

    We study gravitational lensing by a recently proposed black hole solution in loop quantum gravity. We highlight the fact that the quantum gravity corrections to the Schwarzschild metric in this model evade the "mass suppression" effects (that the usual quantum gravity corrections are susceptible to) by virtue of one of the parameters in the model being dimensionless, which is unlike any other quantum gravity motivated parameter. Gravitational lensing in the strong and weak deflection regimes is studied, and a sample consistency relation is presented which could serve as a test of this model. We discuss that, though the consistency relation for this model is qualitatively similar to what would have been in Brans-Dicke, in general it can be a good discriminator between many alternative theories. Although the observational prospects do not seem to be very optimistic even for a galactic supermassive black hole case, time delay between relativistic images for a billion solar mass black holes in other galaxies might be within reach of future relativistic lensing observations.

  7. Contact lenses in aviation: the Marine Corps experience.

    PubMed

    Mittelman, M H; Siegel, B; Still, D L

    1993-06-01

    In an attempt to limit safety and health risks, Naval Aeromedical Policy has historically prohibited the use of contact lenses in the Navy and Marine Corps Class 1 Aviation Personnel (pilots), approximately 18% of whom require spectacles. Recent technological advancements have rendered spectacles functionally incompatible with some mission-essential masks, goggles, and imaging devices, thus forcing a re-examination of existing policy. Recent U.S. Army and U.S. Air Force aviation studies favorably compare the performance of contact lenses to spectacles. In order to test the application of contact lenses in the unique U.S. Marine Corps aviation environment, encompassing shipboard, land-based, and forwardly-deployed units, 90 aviation personnel assigned to several deploying squadrons were evaluated for contact lenses; flex-wear disposable lenses were the primary modality of choice. Of the subjects, 68 (73%) were successfully fit and continued contact lens wear for a period of 16 months. Safety and health were not compromised, and job performance was favorably affected. No cases of ulcerative keratitis or vision loss were reported. The first U.S. Marine Corps aviation contact lens study supports the growing belief that contact lenses can be safely and effectively applied in the critical and hazardous aviation environment. PMID:8338502

  8. CMB lensing and giant rings

    NASA Astrophysics Data System (ADS)

    Rathaus, Ben; Itzhaki, Nissan

    2012-05-01

    We study the CMB lensing signature of a pre-inationary particle (PIP), assuming it is responsible for the giant rings anomaly that was found recently in the WMAP data. Simulating Planck-like data we find that generically the CMB lensing signal to noise ratio associated with such a PIP is quite small and it would be difficult to cross correlate the temperature giant rings with the CMB lensing signal. However, if the pre-inationary particle is also responsible for the bulk flow measured from the local large scale structure, which happens to point roughly at the same direction as the giant rings, then the CMB lensing signal to noise ratio is fairly significant.

  9. Ophthalmic halo reduced lenses design

    NASA Astrophysics Data System (ADS)

    Limon, Ofer; Zalevsky, Zeev

    2015-05-01

    The halo effect is a very problematic visual artifact occurring in extended depth of focus or multi-focal ophthalmic lenses such as e.g. intra-ocular (after cataract surgery) or contact lenses when used in dark illumination conditions. This artifact is generated due to surface structures added on top of those lenses in order to increase their depth of focus or to realize multiple focal lengths. In this paper we present novel solution that can resolve this major problem of ophthalmic lenses. The proposed solution involves modification to the surface structure that realizes the extended depth of focus. Our solution is fabricated and numerically and experimentally validated also in preliminary in-vivo trials.

  10. HUBBLE'S TOP TEN GRAVITATIONAL LENSES

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The NASA Hubble Space Telescope serendipitous survey of the sky has uncovered exotic patterns, rings, arcs and crosses that are all optical mirages produced by a gravitational lens, nature's equivalent of having giant magnifying glass in space. Shown are the top 10 lens candidates uncovered in the deepest 100 Hubble fields. Hubble's sensitivity and high resolution allow it to see faint and distant lenses that cannot be detected with ground-based telescopes whose images are blurred by Earth's atmosphere. [Top Left] - HST 01248+0351 is a lensed pair on either side of the edge-on disk lensing galaxy. [Top Center] - HST 01247+0352 is another pair of bluer lensed source images around the red spherical elliptical lensing galaxy. Two much fainter images can be seen near the detection limit which might make this a quadruple system. [Top Right] - HST 15433+5352 is a very good lens candidate with a bluer lensed source in the form of an extended arc about the redder elliptical lensing galaxy. [Middle Far Left] - HST 16302+8230 could be an 'Einstein ring' and the most intriguing lens candidate. It has been nicknamed the 'the London Underground' since it resembles that logo. [Middle Near Left] - HST 14176+5226 is the first, and brightest lens system discovered in 1995 with the Hubble telescope. This lens candidate has now been confirmed spectroscopically using large ground-based telescopes. The elliptical lensing galaxy is located 7 billion light-years away, and the lensed quasar is about 11 billion light-years distant. [Middle Near Right] - HST 12531-2914 is the second quadruple lens candidate discovered with Hubble. It is similar to the first, but appears smaller and fainter. [Middle Far Right] - HST 14164+5215 is a pair of bluish lensed images symmetrically placed around a brighter, redder galaxy. [Bottom Left] - HST 16309+8230 is an edge-on disk-like galaxy (blue arc) which has been significantly distorted by the redder lensing elliptical galaxy. [Bottom Center] - HST 12368

  11. A Modern Series Of Cinematographic Lenses: From Concept To Product

    NASA Astrophysics Data System (ADS)

    Neil, lain A.

    1988-06-01

    In the past photographic "taking" lenses and, in particular, those for the motion picture industry i.e. cinematographic lenses have had a mixed career due to inconsistencies between the processes of lens design, manufacture, testing and calibration and practical assessment in the customer domain. Usually these inconsistencies can be attributed to differences between the comparison of, a lens design "scientifically" made and final evaluation in an "artistic" manner. The following paper addresses the processes of lens design, manufacture, testing and calibration using a combination of acquired practical experience and modern test and calibration methods. Various performance aspects are separately addressed and considered in terms of different means of measurement.

  12. The Thirring-Lense Effect

    NASA Astrophysics Data System (ADS)

    Embacher, Franz

    The Thirring-Lense effect is the phenomenon that an observer near a rotating mass, being in a state which is non-rotating with respect to the rest of the universe, experiences extra inertial forces, i.e. becomes dizzy. The first anticipation of the effect goes back to Ernst Mach; its first quantitative prediction on the basis of general relativity was given by Hans Thirring and Joseph Lense. Almost ninety years later, the effect seems to be experimentally verified.

  13. Antireflection coatings for submillimeter silicon lenses

    NASA Astrophysics Data System (ADS)

    Wheeler, Jordan D.; Koopman, Brian; Gallardo, Patricio; Maloney, Philip R.; Brugger, Spencer; Cortes-Medellin, German; Datta, Rahul; Dowell, C. Darren; Glenn, Jason; Golwala, Sunil; McKenney, Chris; McMahon, Jeffery J.; Munson, Charles D.; Niemack, Mike; Parshley, Stephen; Stacey, Gordon

    2014-07-01

    Low-loss lenses are required for submillimeter astronomical applications, such as instrumentation for CCAT, a 25 m diameter telescope to be built at an elevation of 18,400 ft in Chile. Silicon is a leading candidate for dielectric lenses due to its low transmission loss and high index of refraction; however, the latter can lead to large reflection losses. Additionally, large diameter lenses (up to 40 cm), with substantial curvature present a challenge for fabrication of antireflection coatings. Three anti-reflection coatings are considered: a deposited dielectric coating of Parylene C, fine mesh structures cut with a dicing saw, and thin etched silicon layers (fabricated with deep reactive ion etching) for bonding to lenses. Modeling, laboratory measurements, and practicalities of fabrication for the three coatings are presented and compared. Measurements of the Parylene C anti-reflection coating were found to be consistent with previous studies and can be expected to result in a 6% transmission loss for each interface from 0.787 to 0.908 THz. The thin etched silicon layers and fine mesh structure anti-reflection coatings were designed and fabricated on test silicon wafers and found to have reflection losses less than 1% at each interface from 0.787 to 0.908 THz. The thin etched silicon layers are our preferred method because of high transmission efficiency while having an intrinsically faster fabrication time than fine structures cut with dicing saws, though much work remains to adapt the etched approach to curved surfaces and optics < 4" in diameter unlike the diced coatings.

  14. A New Type of X-ray Condenser Lenses with Large Apertures Fabricated by Rolling of Structured Films

    SciTech Connect

    Simon, M.; Reznikova, E.; Nazmov, V.; Grund, T.; Last, A.

    2010-04-06

    In order to meet the demand for X-ray lenses with large apertures and, hence, photon flux, a new type of X-ray lenses has been developed: Rolled prismatic X-ray lenses feature a vast number of refracting surfaces to increase transparency and aperture, respectively. Prototypes of such lenses have been fabricated by molding and rolling of a structured polyimide film. In this work, rolled prismatic X-ray lenses are pictured, and results of first tests performed at the ANKA storage ring in Karlsruhe are presented.

  15. Multifocal intraocular lenses and glare.

    PubMed

    Akutsu, H; Legge, G E; Luebker, A; Lindstrom, R L; Zabel, R W; Kirby, V M

    1993-06-01

    In a previous paper, we reported finding deficits in the contrast sensitivity functions of patients with diffractive multifocal intraocular lenses (IOL's). The results were consistent with optical measurements of the modulation transfer function (MTF) of the IOL. When this MTF is treated as a linear spatial frequency filter, it predicts the existence of a glare effect; contrast threshold for the recognition of target letters should be elevated by a bright, adjacent stimulus. We tested this prediction by measuring contrast thresholds for recognizing 0.2 degrees Sloan letters on a background luminance of 11.2 cd/m2. The letters were presented inside bright (300 cd/m2) annular rings with inner diameters ranging from 0.42 to 1.22 degrees. Thresholds were measured for seven multifocal subjects, age-matched groups of monofocal subjects and phakic-control subjects, and a young group. Multifocal subjects exhibited a greater glare effect than monofocal subjects, and they in turn exhibited a greater effect than phakic-control subjects. The observed glare effect for multifocal subjects was about twice that expected from the spatial filtering property of the multifocal IOL. PMID:8336911

  16. Micro-optofluidic Lenses: A review

    PubMed Central

    Nguyen, Nam-Trung

    2010-01-01

    This review presents a systematic perspective on the development of micro-optofluidic lenses. The progress on the development of micro-optofluidic lenses are illustrated by example from recent literature. The advantage of micro-optofluidic lenses over solid lens systems is their tunability without the use of large actuators such as servo motors. Depending on the relative orientation of light path and the substrate surface, micro-optofluidic lenses can be categorized as in-plane or out-of-plane lenses. However, this review will focus on the tunability of the lenses and categorizes them according to the concept of tunability. Micro-optofluidic lenses can be either tuned by the liquid in use or by the shape of the lens. Micro-optofluidic lenses with tunable shape are categorized according to the actuation schemes. Typical parameters of micro-optofluidic lenses reported recently are compared and discussed. Finally, perspectives are given for future works in this field. PMID:20714369

  17. Observing cosmic string loops with gravitational lensing surveys

    SciTech Connect

    Mack, Katherine J.; Wesley, Daniel H.; King, Lindsay J.

    2007-12-15

    We show that the existence of cosmic strings can be strongly constrained by the next generation of gravitational lensing surveys at radio frequencies. We focus on cosmic string loops, which simulations suggest would be far more numerous than long (horizon-sized) strings. Using simple models of the loop population and minimal assumptions about the lensing cross section per loop, we estimate the optical depth to lensing and show that extant radio surveys such as CLASS have already ruled out a portion of the cosmic string model parameter space. Future radio interferometers, such as LOFAR and especially SKA, may constrain G{mu}/c{sup 2}<10{sup -9} in some regions of parameter space, outperforming current constraints from pulsar timing and the cosmic microwave backgound by up to two orders of magnitude. This method relies on direct detections of cosmic strings, and so is less sensitive to the theoretical uncertainties in string network evolution that weaken other constraints.

  18. Gravitational lensing by rotating naked singularities

    SciTech Connect

    Gyulchev, Galin N.; Yazadjiev, Stoytcho S.

    2008-10-15

    We model massive compact objects in galactic nuclei as stationary, axially symmetric naked singularities in the Einstein-massless scalar field theory and study the resulting gravitational lensing. In the weak deflection limit we study analytically the position of the two weak field images, the corresponding signed and absolute magnifications as well as the centroid up to post-Newtonian order. We show that there are static post-Newtonian corrections to the signed magnification and their sum as well as to the critical curves, which are functions of the scalar charge. The shift of the critical curves as a function of the lens angular momentum is found, and it is shown that they decrease slightly for the weakly naked and vastly for the strongly naked singularities with the increase of the scalar charge. The pointlike caustics drift away from the optical axis and do not depend on the scalar charge. In the strong deflection limit approximation, we compute numerically the position of the relativistic images and their separability for weakly naked singularities. All of the lensing quantities are compared to particular cases as Schwarzschild and Kerr black holes as well as Janis-Newman-Winicour naked singularities.

  19. WEAK-LENSING RESULTS FOR THE MERGING CLUSTER A1758

    SciTech Connect

    Ragozzine, B.; Clowe, D.; Markevitch, M.; Gonzalez, A. H.; Bradac, M.

    2012-01-10

    Here we present the weak-lensing results for A1758, which is known to consist of four subclusters undergoing two separate mergers, A1758N and A1758S. Weak-lensing results for A1758N agree with previous weak-lensing results for clusters 1E0657-558 (Bullet cluster) and MACS J0025.4-1222, whose X-ray gas components were found to be largely separated from their clusters' gravitational potentials. A1758N has a geometry that is different from previously published mergers in that one of its X-ray peaks overlays the corresponding gravitational potential and the other X-ray peak is well separated from its cluster's gravitational potential. The weak-lensing mass peaks of the two northern clusters are separated at the 2.5{sigma} level. We estimate the combined mass of the clusters in A1758N to be (2.2 {+-} 0.5) Multiplication-Sign 10{sup 15} M{sub Sun} and r{sub 200} = 2300{sup +100}{sub -130} kpc. We also detect seven strong-lensing candidates, two of which may provide information that would improve the mass measurements of A1758N.

  20. Thermal lensing in ocular media

    NASA Astrophysics Data System (ADS)

    Vincelette, Rebecca Lee

    2009-12-01

    This research was a collaborative effort between the Air Force Research Laboratory (AFRL) and the University of Texas to examine the laser-tissue interaction of thermal lensing induced by continuous-wave, CW, near-infrared, NIR, laser radiation in the eye and its influence on the formation of a retinal lesion from said radiation. CW NIR laser radiation can lead to a thermal lesion induced on the retina given sufficient power and exposure duration as related to three basic parameters; the percent of transmitted energy to, the optical absorption of, and the size of the laser-beam created at the retina. Thermal lensing is a well-known phenomenon arising from the optical absorption, and subsequent temperature rise, along the path of the propagating beam through a medium. Thermal lensing causes the laser-beam profile delivered to the retina to be time dependent. Analysis of a dual-beam, multidimensional, high-frame rate, confocal imaging system in an artificial eye determined the rate of thermal lensing in aqueous media exposed to 1110, 1130, 1150 and 1318-nm wavelengths was related to the power density created along the optical axis and linear absorption coefficient of the medium. An adaptive optics imaging system was used to record the aberrations induced by the thermal lens at the retina in an artificial eye during steady-state. Though the laser-beam profiles changed over the exposure time, the CW NIR retinal damage thresholds between 1110--1319-nm were determined to follow conventional fitting algorithms which neglected thermal lensing. A first-order mathematical model of thermal lensing was developed by conjoining an ABCD beam propagation method, Beer's law of attenuation, and a solution to the heat-equation with respect to radial diffusion. The model predicted that thermal lensing would be strongest for small (< 4-mm) 1/e2 laser-beam diameters input at the corneal plane and weakly transmitted wavelengths where less than 5% of the energy is delivered to the retina

  1. Weak lensing and cosmological investigation

    NASA Astrophysics Data System (ADS)

    Acquaviva, Viviana

    2005-03-01

    In the last few years the scientific community has been dealing with the challenging issue of identifying the dark energy component. We regard weak gravitational lensing as a brand new, and extremely important, tool for cosmological investigation in this field. In fact, the features imprinted on the Cosmic Microwave Background radiation by the lensing from the intervening distribution of matter represent a pretty unbiased estimator, and can thus be used for putting constraints on different dark energy models. This is true in particular for the magnetic-type B-modes of CMB polarization, whose unlensed spectrum at large multipoles (l ~= 1000) is very small even in presence of an amount of gravitational waves as large as currently allowed by the experiments: therefore, on these scales the lensing phenomenon is the only responsible for the observed power, and this signal turns out to be a faithful tracer of the dark energy dynamics. We first recall the formal apparatus of the weak lensing in extended theories of gravity, introducing the physical observables suitable to cast the bridge between lensing and cosmology, and then evaluate the amplitude of the expected effect in the particular case of a Non-Minimally-Coupled model, featuring a quadratic coupling between quintessence and Ricci scalar.

  2. Surface gravity-wave lensing.

    PubMed

    Elandt, Ryan B; Shakeri, Mostafa; Alam, Mohammad-Reza

    2014-02-01

    Here we show that a nonlinear resonance between oceanic surface waves caused by small seabed features (the so-called Bragg resonance) can be utilized to create the equivalent of lenses and curved mirrors for surface gravity waves. Such gravity wave lenses, which are merely small changes to the seafloor topography and therefore are surface noninvasive, can focus or defocus the energy of incident waves toward or away from any desired focal point. We further show that for a broadband incident wave spectrum (i.e., a wave group composed of a multitude of different-frequency waves), a polychromatic topography (occupying no more than the area required for a monochromatic lens) can achieve a broadband lensing effect. Gravity wave lenses can be utilized to create localized high-energy wave zones (e.g., for wave energy harvesting or creating artificial surf zones) as well as to disperse waves in order to create protected areas (e.g., harbors or areas near important offshore facilities). In reverse, lensing of oceanic waves may be caused by natural seabed features and may explain the frequent appearance of very high amplitude waves in certain bodies of water. PMID:25353576

  3. Cosmology with weak lensing surveys.

    PubMed

    Munshi, Dipak; Valageas, Patrick

    2005-12-15

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening mass. Since the lensing effects arise from deflections of the light rays due to fluctuations of the gravitational potential, they can be directly related to the underlying density field of the large-scale structures. Weak gravitational surveys are complementary to both galaxy surveys and cosmic microwave background observations as they probe unbiased nonlinear matter power spectra at medium redshift. Ongoing CMBR experiments such as WMAP and a future Planck satellite mission will measure the standard cosmological parameters with unprecedented accuracy. The focus of attention will then shift to understanding the nature of dark matter and vacuum energy: several recent studies suggest that lensing is the best method for constraining the dark energy equation of state. During the next 5 year period, ongoing and future weak lensing surveys such as the Joint Dark Energy Mission (JDEM; e.g. SNAP) or the Large-aperture Synoptic Survey Telescope will play a major role in advancing our understanding of the universe in this direction. In this review article, we describe various aspects of probing the matter power spectrum and the bi-spectrum and other related statistics with weak lensing surveys. This can be used to probe the background dynamics of the universe as well as the nature of dark matter and dark energy. PMID:16286284

  4. FASTLens (FAst STatistics for weak Lensing): Fast Method for Weak Lensing Statistics and Map Making

    NASA Astrophysics Data System (ADS)

    Pires, S.; Starck, J.-L.; Amara, A.; Teyssier, R.; Refregier, A.; Fadili, J.

    2010-10-01

    The analysis of weak lensing data requires to account for missing data such as masking out of bright stars. To date, the majority of lensing analyses uses the two point-statistics of the cosmic shear field. These can either be studied directly using the two-point correlation function, or in Fourier space, using the power spectrum. The two-point correlation function is unbiased by missing data but its direct calculation will soon become a burden with the exponential growth of astronomical data sets. The power spectrum is fast to estimate but a mask correction should be estimated. Other statistics can be used but these are strongly sensitive to missing data. The solution that is proposed by FASTLens is to properly fill-in the gaps with only NlogN operations, leading to a complete weak lensing mass map from which one can compute straight forwardly and with a very good accuracy any kind of statistics like power spectrum or bispectrum.

  5. Key Science with the Square Kilometer Array: Strong-field Tests of Gravity using Pulsars and Black Holes

    NASA Astrophysics Data System (ADS)

    Cordes, J. M.; Kramer, M.; Backer, D. C.; Lazio, T. J. W.; Science Working Groupthe Square Kilometer Array Team

    2005-12-01

    A Galactic census of pulsars with the SKA will discover most of the active pulsars in the Galaxy beamed toward us. The sheer number of pulsars discovered, along with the exceptional timing precision the SKA can provide, will revolutionize the field of pulsar astrophysics and will enable significant tests of theories of gravity. Census discoveries will almost certainly include pulsar-black hole binaries as well as pulsars orbiting the super-massive black hole in the Galactic center. These systems provide unique opportunties for probing the ultra-strong field limit of relativistic gravity and will complement future gravitational wave detections using LISA-like instruments. SKA measurements can be used to test the Cosmic Censorship Conjecture and the No-Hair theorem. The large number of millisecond pulsars discovered with the SKA will also provide a dense array of precision clocks on the sky that can be used as multiple arms of a cosmic gravitational wave detector, which can be used to detect and measure the stochastic cosmological gravitational wave background that is expected from a number of sources. In addition to gravitational tests, the large number of lines of sight will provide a detailed map of the Galaxy's electron density and magnetic fields and important information on the dynamics and evolutionary histories of neutron stars. The census will provide examples of nearly every possible outcome of the evolution of massive stars, including (as above) pulsar black-hole systems and sub-millisecond pulsars, if they exist. These objects will yield constraints on the equation of state of matter at super-nuclear densities. Masses of pulsars and their binary companions planets, white dwarfs, other neutron stars, and black holes will be determined to ˜ 1% for hundreds of objects. The SKA will also provide partial censuses of nearby galaxies through periodicity and giant-pulse detections, yielding important information on the intergalactic medium.

  6. SDSS J094604.90+183541.8: A GRAVITATIONALLY LENSED QUASAR AT z = 4.8

    SciTech Connect

    McGreer, Ian D.; Fan Xiaohui; Bian Fuyan; Farnsworth, Kara; Hall, Patrick B.; Inada, Naohisa; Oguri, Masamune; Strauss, Michael A.; Schneider, Donald P.

    2010-08-15

    We report the discovery of a gravitationally lensed quasar identified serendipitously in the Sloan Digital Sky Survey (SDSS). The object, SDSS J094604.90+183541.8, was initially targeted for spectroscopy as a luminous red galaxy, but the SDSS spectrum has the features of both a z = 0.388 galaxy and a z = 4.8 quasar. We have obtained additional imaging that resolves the system into two quasar images separated by 3.''06 and a bright galaxy that is strongly blended with one of the quasar images. We confirm spectroscopically that the two quasar images represent a single-lensed source at z = 4.8 with a total magnification of 3.2, and we derive a model for the lensing galaxy. This is the highest redshift lensed quasar currently known. We examine the issues surrounding the selection of such an unusual object from existing data and briefly discuss implications for lensed quasar surveys.

  7. RCSLenS: The Red Cluster Sequence Lensing Survey

    NASA Astrophysics Data System (ADS)

    Hildebrandt, H.; Choi, A.; Heymans, C.; Blake, C.; Erben, T.; Miller, L.; Nakajima, R.; van Waerbeke, L.; Viola, M.; Buddendiek, A.; Harnois-Déraps, J.; Hojjati, A.; Joachimi, B.; Joudaki, S.; Kitching, T. D.; Wolf, C.; Gwyn, S.; Johnson, N.; Kuijken, K.; Sheikhbahaee, Z.; Tudorica, A.; Yee, H. K. C.

    2016-08-01

    We present the Red-sequence Cluster Lensing Survey (RCSLenS), an application of the methods developed for the Canada France Hawaii Telescope Lensing Survey (CFHTLenS) to the ˜785 deg2, multi-band imaging data of the Red-sequence Cluster Survey 2 (RCS2). This project represents the largest public, sub-arcsecond seeing, multi-band survey to date that is suited for weak gravitational lensing measurements. With a careful assessment of systematic errors in shape measurements and photometric redshifts we extend the use of this data set to allow cross-correlation analyses between weak lensing observables and other data sets. We describe the imaging data, the data reduction, masking, multi-colour photometry, photometric redshifts, shape measurements, tests for systematic errors, and a blinding scheme to allow for more objective measurements. In total we analyse 761 pointings with r-band coverage, which constitutes our lensing sample. Residual large-scale B-mode systematics prevent the use of this shear catalogue for cosmic shear science. The effective number density of lensing sources over an unmasked area of 571.7 deg2 and down to a magnitude limit of r ˜ 24.5 is 8.1 galaxies per arcmin2 (weighted: 5.5 arcmin-2) distributed over 14 patches on the sky. Photometric redshifts based on 4-band griz data are available for 513 pointings covering an unmasked area of 383.5 deg2. We present weak lensing mass reconstructions of some example clusters as well as the full survey representing the largest areas that have been mapped in this way. All our data products are publicly available through CADC at http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/community/rcslens/query.html in a format very similar to the CFHTLenS data release.

  8. The Future of Myopia Control Contact Lenses.

    PubMed

    Gifford, Paul; Gifford, Kate Louise

    2016-04-01

    The growing incidence of pediatric myopia worldwide has generated strong scientific interest in understanding factors leading to myopia development and progression. Although contact lenses (CLs) are prescribed primarily for refractive correction, there is burgeoning use of particular modalities for slowing progression of myopia following reported success in the literature. Standard soft and rigid CLs have been shown to have minimal or no effect for myopia control. Overall, orthokeratology and soft multifocal CLs have shown the most consistent performance for myopia control with the least side effects. However, their acceptance in both clinical and academic spheres is influenced by data limitations, required off-label usage, and a lack of clear understanding of their mechanisms for myopia control. Myopia development and progression seem to be multifactorial, with a complex interaction between genetics and environment influencing myopigenesis. The optical characteristics of the individual also play a role through variations in relative peripheral refraction, binocular vision function, and inherent higher-order aberrations that have been linked to different refractive states. Contact lenses provide the most viable opportunity to beneficially modify these factors through their close alignment with the eye and consistent wearing time. Contact lenses also have potential to provide a pharmacological delivery device and a possible feedback mechanism for modification of a visual environmental risk. An examination of current patents on myopia control provides a window to the future development of an ideal myopia-controlling CL, which would incorporate the broadest treatment of all currently understood myopigenic factors. This ideal lens must also satisfy safety and comfort aspects, along with overcoming practical issues around U.S. Food and Drug Administration approval, product supply, and availability to target populations. Translating the broad field of myopia research

  9. Electron beam generation in Tevatron electron lenses

    SciTech Connect

    Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.; /Novosibirsk, IYF

    2006-08-01

    New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices.

  10. Construction progress of the RHIC electron lenses

    SciTech Connect

    Fischer W.; Altinbas, Z.; Anerella, M.; Beebe, E.; et al

    2012-05-20

    In polarized proton operation the RHIC performance is limited by the head-on beam-beam effect. To overcome this limitation two electron lenses are under construction. We give an overview of the construction progress. Guns, collectors and the warm electron beam transport solenoids with their power supplies have been constructed. The superconducting solenoids that guide the electron beam during the interaction with the proton beam are near completion. A test stand has been set up to verify the performance of the gun, collector and some of the instrumentation. The infrastructure is being prepared for installation, and simulations continue to optimize the performance.

  11. Transmission of the normal and cataractous lenses.

    PubMed

    Bielski, A; Robaczewski, T; Wolnikowski, J; Bieganowski, L

    1991-01-01

    Results of measurements of the transmission (total and in line) of cataractous lenses are presented. A magnitude is introduced which can be used as a measure of the in vitro opacity of lenses. PMID:1911631

  12. Visual Reliability : The Conception Of Varilux Lenses

    NASA Astrophysics Data System (ADS)

    Lenne, William

    1986-05-01

    There is currently very rapid development of progressive lenses ; indeed, these lenses have been the subject of numerous studies, which show their remarkable aptitude for the correction of presbyopia.

  13. Astrophysical Uses Of Cmb Lensing

    NASA Astrophysics Data System (ADS)

    Das, Sudeep

    2009-01-01

    The future of Cosmic Microwave Background (CMB) research lies in exploiting the arcminute scale secondary anisotropies which encode information about the late time interaction of the CMB photons with the structure in the Universe. A specific form of such interaction is the gravitational lensing of the CMB - the main topic of this thesis. Upcoming experiments like ACT, SPT and PLANCK will measure these anisotropies with unprecedented resolution and sensitivity. In this thesis, we present new techniques to model and analyse such high resolution data and explore the implications of such measurements on Cosmology. First, we describe a novel method for simulating high resolution large sky lensed CMB maps. Maps simulated through this method will be instrumental in developing the detection and analysis techniques for CMB lensing. Second, we describe a new and efficient method for measuring the power spectrum of arcminute resolution CMB maps. At these resolutions, aliasing of power due to hard edges and point source masks become a serious problem. Our method efficiently remedies these problems and the reduces uncertainties in the final power spectrum estimate by several factors over those obtainable by the now standard methods. This technique will be also useful for estimating higher order statistics from the maps, like the ones related to the detection of CMB lensing and its cross-correlation with large scale structure. Next, we exemplify how such cross-correlations can be turned into Cosmological probes. We propose an estimator for cosmological distance ratios based on CMB and galaxy lensing and show that it can be measured to sufficient accuracy in future experiments to be Cosmologically useful. Finally, we show that CMB lensing can be used to constrain the void and the texture hypotheses that have been put forward for explaining the intriguing Cold Spot anomaly in the WMAP data.

  14. Terahertz super thin planar lenses

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Ye, Jiasheng; Hu, Dan; Wang, Xinke; Feng, Shengfei; Sun, Wenfeng

    2012-12-01

    Terahertz (THz) radiation is an under developing range in the electromagnetic spectrum. It has attracted a lot of attentions due to its various potential applications. However, THz systems are difficult to be integrated into a smart size due to the limitation of its long wavelength. In this presentation, we propose a new approach to design planar lenses with a thickness of several hundred nanometers in the THz range. The fabricated lenses are characterized with a focal plane imaging system and it is found that they can focus the THz light and image an object well. It is expected that this new approach can pave a way for smart THz systems integration.

  15. Improved key integrity checking for high-speed quantum key distribution using combinatorial group testing with strongly selective family design

    NASA Astrophysics Data System (ADS)

    Fang, Junbin; Jiang, Zoe L.; Ren, Kexin; Luo, Yunhan; Chen, Zhe; Liu, Weiping; Wang, Xuan; Niu, Xiamu; Yiu, S. M.; Hui, Lucas C. K.

    2014-06-01

    Key integrity checking is a necessary process in practical quantum key distribution (QKD) to check whether there is any error bit escaped from the previous error correction procedure. The traditional single-hash method may become a bottleneck in high-speed QKD since it has to discard all the key bits even if just one error bit exists. In this paper, we propose an improved scheme using combinatorial group testing (CGT) based on strong selective family design to verify key integrity in fine granularity and consequently improve the total efficiency of key generation after the error correction procedure. Code shortening technique and parallel computing are also applied to enhance the scheme's flexibility and to accelerate the computation. Experimental results show that the scheme can identify the rare error bits precisely and thus avoid dropping the great majority of correct bits, while the overhead is reasonable. For a -bit key, the disclosed information for public comparison is 800 bits (about 0.076 % of the key bits), reducing 256 bits when compared with the previous CGT scheme. Besides, with an Intel® quad-cores CPU at 3.40 GHz and 8 GB RAM, the computational times are 3.0 and 6.3 ms for hashing and decoding, respectively, which are reasonable in real applications and will not cause significant latency in practical QKD systems.

  16. Uncertainties in pixel-based source reconstruction for gravitationally lensed objects and applications to lensed galaxies

    NASA Astrophysics Data System (ADS)

    Tagore, Amitpal Singh

    Gravitational lens modeling of spatially resolved sources is a challenging inverse problem that can involve many observational constraints and model parameters. I present a new software package, pixsrc, that works in conjunction with the lensmodel software and builds on established pixel-based source reconstruction (PBSR) algorithms for de-lensing a source and constraining lens model parameters. Using test data, I explore statistical and systematic uncertainties associated with gridding, source regularization, interpolation errors, noise, and telescope pointing. I compare two gridding schemes in the source plane: a fully adaptive grid and an adaptive Cartesian grid. I also consider regularization schemes that minimize derivatives of the source and introduce a scheme that minimizes deviations from an analytic source profile. Careful choice of gridding and regularization can reduce "discreteness noise" in the chi2 surface that is inherent in the pixel-based methodology. With a gridded source, errors due to interpolation need to be taken into account (especially for high S/N data). Different realizations of noise and telescope pointing lead to slightly different values for lens model parameters, and the scatter between different "observations" can be comparable to or larger than the model uncertainties themselves. The same effects create scatter in the lensing magnification at the level of a few percent for a peak S/N of 10. I then apply pixsrc to observations of lensed, high-redshift galaxies. SDSS J0901+1814, is an ultraluminous infrared galaxy at z=2.26 that is also UV-bright, and it is lensed by a foreground group of galaxies at z=0.35. I constrain the lens model using maps of CO(3-2) rotational line emission and optical imaging and apply the lens model to observations of CO(1-0), H-alpha, and [NII] line emission as well. Using the de-lensed images, I calculate properties of the source, such as the gas mass fraction and dynamical mass. Finally, I examine a

  17. Nanoplasmonic lenses for bacteria sorting (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Zhu, Xiangchao; Yanik, Ahmet A.

    2015-08-01

    We demonstrate that patches of two dimensional arrays of circular plasmonic nanoholes patterned on gold-titanium thin film enables subwavelength focusing of visible light in far field region. Efficient coupling of the light with the excited surface plasmon at metal dielectric interface results in strong light transmission. As a result, surface plasmon plays an important role in the far field focusing behavior of the nanohole-aperture patches device. Furthermore, the focal length of the focused beam was found to be predominantly dependent on the overall size of the patch, which is in good agreement with that calculated by Rayleigh-Sommerfield integral formula. The focused light beam can be utilized to separate bio-particles in the dynamic range from 0.1 μm to 1 μm through mainly overcoming the drag force induced by fluid flow. In our proposed model, focused light generated by our plasmonic lenses will push the larger bio-particles in size back to the source of fluid flow and allow the smaller particles to move towards the central aperture of the patch. Such a new kind of plasmonic lenses open up possibility of sorting bacterium-like particles with plasmonic nanolenses, and also represent a promising tool in the field of virology.

  18. Dynamic Spectral Mapping of Interstellar Plasma Lenses

    NASA Astrophysics Data System (ADS)

    Tuntsov, Artem V.; Walker, Mark A.; Koopmans, Leon V. E.; Bannister, Keith W.; Stevens, Jamie; Johnston, Simon; Reynolds, Cormac; Bignall, Hayley E.

    2016-02-01

    Compact radio sources sometimes exhibit intervals of large, rapid changes in their flux density, due to lensing by interstellar plasma crossing the line of sight. A novel survey program has made it possible to discover these “Extreme Scattering Events” (ESEs) in real time, resulting in a high-quality dynamic spectrum of an ESE observed in PKS 1939-315. Here we present a method for determining the column-density profile of a plasma lens, given only the dynamic radio spectrum of the lensed source, under the assumption that the lens is either axisymmetric or totally anisotropic. Our technique relies on the known, strong frequency dependence of the plasma refractive index in order to determine how points in the dynamic spectrum map to positions on the lens. We apply our method to high-frequency (4.2-10.8 GHz) data from the Australia Telescope Compact Array of the PKS 1939-315 ESE. The derived electron column-density profiles are very similar for the two geometries we consider, and both yield a good visual match to the data. However, the fit residuals are substantially above the noise level, and deficiencies are evident when we compare the predictions of our model to lower-frequency (1.6-3.1 GHz) data on the same ESE, thus motivating future development of more sophisticated inversion techniques.

  19. N-body lensed CMB maps: lensing extraction and characterization

    SciTech Connect

    Antolini, Claudia; Martinelli, Matteo; Baccigalupi, Carlo; Fantaye, Yabebal; Carbone, Carmelita E-mail: y.t.fantaye@astro.uio.no E-mail: carmelita.carbone@brera.inaf.it

    2014-02-01

    We reconstruct shear maps and angular power spectra from simulated weakly lensed total intensity (TT) and polarised (EB) maps of the Cosmic Microwave Background (CMB) anisotropies, obtained using Born approximated ray-tracing through the N-body simulated Cold Dark Matter (CDM) structures in the Millennium Simulations (MS). We compare the recovered signal with the ΛCDM prediction, on the whole interval of angular scales which is allowed by the finite box size, extending from the degree scale to the arcminute, by applying a quadratic estimator in the flat sky limit; we consider PRISM-like instrumental specification for future generation CMB satellites, corresponding to arcminute angular resolution of 3.2' and sensitivity of 2.43 μK-arcmin. The noise contribution in the simulations closely follows the estimator prediction, becoming dominated by limits in the angular resolution for the EB signal, at ℓ ≅ 1500. The recovered signal shows no visible departure from predictions of the weak lensing power within uncertainties, when considering TT and EB data singularly. In particular, the reconstruction precision reaches the level of a few percent in bins with Δℓ ≅ 100 in the angular multiple interval 1000∼<ℓ∼<2000 for T, and about 10% for EB. Within the adopted specifications, polarisation data do represent a significant contribution to the lensing shear, which appear to faithfully trace the underlying N-body structure down to the smallest angular scales achievable with the present setup, validating at the same time the latter with respect to semi-analytical predictions from ΛCDM cosmology at the level of CMB lensing statistics. This work demonstrates the feasibility of CMB lensing studies based on large scale simulations of cosmological structure formation in the context of the current and future high resolution and sensitivity CMB experiment.

  20. Transmittance Variations Analysis in Sunglasses Lenses Post Sun Exposure

    NASA Astrophysics Data System (ADS)

    Loureiro, A. D.; Gomes, L. M.; Ventura, L.

    2016-07-01

    The hypothesis that sunglass ultraviolet (UV) protection can degrade with Sun exposure has never been proven experimentally. No sunglasses standards take into account UV transmittance changes after long Sun exposure. We selected 12 sunglass lenses and measured transmittance values from 280 nm to 780 nm. After 50 hours of exposure, new transmittance measurements were taken and transmittance variations inferior to 0.2% were observed. The exposition continues longer and more lenses will be tested to obtain conclusive results. We hope to obtain experimental data to confirm UV protection loss hypothesis and obtain a relation between Sun and solar simulator exposition

  1. Galaxy cluster center detection methods with weak lensing

    NASA Astrophysics Data System (ADS)

    Simet, Melanie

    The precise location of galaxy cluster centers is a persistent problem in weak lensing mass estimates and in interpretations of clusters in a cosmological context. In this work, we test methods of centroid determination from weak lensing data and examine the effects of such self-calibration on the measured masses. Drawing on lensing data from the Sloan Digital Sky Survey Stripe 82, a 275 square degree region of coadded data in the Southern Galactic Cap, together with a catalog of MaxBCG clusters, we show that halo substructure as well as shape noise and stochasticity in galaxy positions limit the precision of such a self-calibration (in the context of Stripe 82, to ˜ 500 h-1 kpc or larger) and bias the mass estimates around these points to a level that is likely unacceptable for the purposes of making cosmological measurements. We also project the usefulness of this technique in future surveys.

  2. Extrusion of compound refractive x-ray lenses.

    SciTech Connect

    Young, K.; Khounsary, A.; Experimental Facilities Division; IIT

    2004-01-01

    Compound refractive lenses (CRLs) are arrays of lenses designed to focus x-rays. The advantage of a focused x-ray beam is improvement in imaging resolution for applications such as microscopy and tomography. CRLs are desirable due to their simple designs and ease in implementation and alignment. One method of fabricating CRLs is extrusion. Extrusion can be employed to produce, for example, aluminum CRLs for high-energy applications because many aluminum products are produced in this manner. Multiple lenses can be extruded in an array in a single run. This method is relatively cost effective compared to others methods of fabricating CRLs. Two generations of extruded aluminum CRLs have been manufactured to date with lens wall thicknesses of 200 and 100 {micro}m, respectively. The first-generation CRL yielded focusing and established the potential to produce high gain if reduced wall thicknesses could be achieved. Testing of the second generation is reported here.

  3. Wink-controlled polarization-switched telescopic contact lenses.

    PubMed

    Schuster, Glenn M; Arianpour, Ashkan; Cookson, Scott; Zhang, Arthur; Hendrik, Lee; O'Brien, Tyrone; Alvarez, Agusto; Ford, Joseph E

    2015-11-10

    We describe a wink-controlled hands-free switching system for eye-borne telescopic vision, based on a previously tested fixed-magnification telescope embedded within scleral contact lenses. Here we integrate orthogonal polarizers into the contact lens covering the F/9.1 refractive 1× and F/9.6 catadioptric 2.8× vision paths, to allow switching via external liquid crystal shutters. We provide hands-free control by an infrared wink/blink monitor, using passive retroreflectors embedded within the contact lenses. We demonstrate system operation of the self-contained switching eyewear and the modified contact lenses with a life-size human eye model with mechanical "eyelids." PMID:26560792

  4. DISCOVERY OF A MULTIPLY LENSED SUBMILLIMETER GALAXY IN EARLY HerMES HERSCHEL/SPIRE DATA

    SciTech Connect

    Conley, A.; Cooray, A.; Kim, S.; Amblard, A.; Vieira, J. D.; Blain, A.; Bock, J.; Bradford, C. M.; Bridge, C.; Carpenter, J. M.; Solares, E. A. Gonzalez; Aguirre, J. E.; Auld, R.; Baker, A. J.; Beelen, A.; Blundell, R.; Brisbin, D.; Burgarella, D.; Chanial, P.

    2011-05-10

    We report the discovery of a bright (f(250 {mu}m)>400 mJy), multiply lensed submillimeter galaxy HERMES J105751.1+573027 in Herschel/SPIRE Science Demonstration Phase data from the HerMES project. Interferometric 880 {mu}m Submillimeter Array observations resolve at least four images with a large separation of {approx}9''. A high-resolution adaptive optics K{sub p} image with Keck/NIRC2 clearly shows strong lensing arcs. Follow-up spectroscopy gives a redshift of z = 2.9575, and the lensing model gives a total magnification of {mu} {approx} 11 {+-} 1. The large image separation allows us to study the multi-wavelength spectral energy distribution (SED) of the lensed source unobscured by the central lensing mass. The far-IR/millimeter-wave SED is well described by a modified blackbody fit with an unusually warm dust temperature, 88 {+-} 3 K. We derive a lensing-corrected total IR luminosity of (1.43 {+-} 0.09) x 10{sup 13} L{sub sun}, implying a star formation rate of {approx}2500 M{sub sun} yr{sup -1}. However, models primarily developed from brighter galaxies selected at longer wavelengths are a poor fit to the full optical-to-millimeter SED. A number of other strongly lensed systems have already been discovered in early Herschel data, and many more are expected as additional data are collected.

  5. MUSE observations of the lensing cluster Abell 1689

    NASA Astrophysics Data System (ADS)

    Bina, D.; Pelló, R.; Richard, J.; Lewis, J.; Patrício, V.; Cantalupo, S.; Herenz, E. C.; Soto, K.; Weilbacher, P. M.; Bacon, R.; Vernet, J. D. R.; Wisotzki, L.; Clément, B.; Cuby, J. G.; Lagattuta, D. J.; Soucail, G.; Verhamme, A.

    2016-05-01

    Context. This paper presents the results obtained with the Multi Unit Spectroscopic Explorer (MUSE) for the core of the lensing cluster Abell 1689, as part of MUSE's commissioning at the ESO Very Large Telescope. Aims: Integral-field observations with MUSE provide a unique view of the central 1 × 1 arcmin2 region at intermediate spectral resolution in the visible domain, allowing us to conduct a complete census of both cluster galaxies and lensed background sources. Methods: We performed a spectroscopic analysis of all sources found in the MUSE data cube. Two hundred and eighty-two objects were systematically extracted from the cube based on a guided-and-manual approach. We also tested three different tools for the automated detection and extraction of line emitters. Cluster galaxies and lensed sources were identified based on their spectral features. We investigated the multiple-image configuration for all known sources in the field. Results: Previous to our survey, 28 different lensed galaxies displaying 46 multiple images were known in the MUSE field of view, most of them were detected through photometric redshifts and lensing considerations. Of these, we spectroscopically confirm 12 images based on their emission lines, corresponding to 7 different lensed galaxies between z = 0.95 and 5.0. In addition, 14 new galaxies have been spectroscopically identified in this area thanks to MUSE data, with redshifts ranging between 0.8 and 6.2. All background sources detected within the MUSE field of view correspond to multiple-imaged systems lensed by A1689. Seventeen sources in total are found at z ≥ 3 based on their Lyman-α emission, with Lyman-α luminosities ranging between 40.5 ≲ log (Lyα) ≲ 42.5 after correction for magnification. This sample is particularly sensitive to the slope of the luminosity function toward the faintest end. The density of sources obtained in this survey is consistent with a steep value of α ≤ -1.5, although this result still

  6. Flat liquid crystal diffractive lenses with variable focus and magnification

    NASA Astrophysics Data System (ADS)

    Valley, Pouria

    Non-mechanical variable lenses are important for creating compact imaging devices. Various methods employing dielectrically actuated lenses, membrane lenses, and liquid crystal lenses were previously proposed [1-4]. In This dissertation the design, fabrication, and characterization of innovative flat tunable-focus liquid crystal diffractive lenses (LCDL) are presented. LCDL employ binary Fresnel zone electrodes fabricated on Indium-Tin-Oxide using conventional micro-photolithography. The light phase can be adjusted by varying the effective refractive index of a nematic liquid crystal sandwiched between the electrodes and a reference substrate. Using a proper voltage distribution across various electrodes the focal length can be changed between several discrete values. Electrodes are shunted such that the correct phase retardation step sequence is achieved. If the number of 2pi zone boundaries is increased by a factor of m the focal length is changed from f to f/m based on the digitized Fresnel zone equation: f = rm2/2mlambda, where r m is mth zone radius, and lambda is the wavelength. The chromatic aberration of the diffractive lens is addressed and corrected by adding a variable fluidic lens. These LCDL operate at very low voltage levels (+/-2.5V ac input), exhibit fast switching times (20-150 ms), can have large apertures (>10 mm), and small form factor, and are robust and insensitive to vibrations, gravity, and capillary effects that limit membrane and dielectrically actuated lenses. Several tests were performed on the LCDL including diffraction efficiency measurement, switching dynamics, and hybrid imaging with a refractive lens. Negative focal lengths are achieved by adjusting the voltages across electrodes. Using these lenses in combination, magnification can be changed and zoom lenses can be formed. These characteristics make LCDL a good candidate for a variety of applications including auto-focus and zoom lenses in compact imaging devices such as camera

  7. Detection of thermal SZ-CMB lensing cross-correlation in Planck nominal mission data

    SciTech Connect

    Hill, J. Colin; Spergel, David N. E-mail: dns@astro.princeton.edu

    2014-02-01

    The nominal mission maps from the Planck satellite contain a wealth of information about secondary anisotropies in the cosmic microwave background (CMB), including those induced by the thermal Sunyaev-Zel'dovich (tSZ) effect and gravitational lensing. As both the tSZ and CMB lensing signals trace the large-scale matter density field, the anisotropies sourced by these processes are expected to be correlated. We report the first detection of this cross-correlation signal, which we measure at 6.2σ significance using the Planck data. We take advantage of Planck's multifrequency coverage to construct a tSZ map using internal linear combination techniques, which we subsequently cross-correlate with the publicly-released Planck CMB lensing potential map. The cross-correlation is subject to contamination from the cosmic infrared background (CIB), which is known to correlate strongly with CMB lensing. We correct for this contamination via cross-correlating our tSZ map with the Planck 857 GHz map and confirm the robustness of our measurement using several null tests. We interpret the signal using halo model calculations, which indicate that the tSZ-CMB lensing cross-correlation is a unique probe of the physics of intracluster gas in high-redshift, low-mass groups and clusters. Our results are consistent with extrapolations of existing gas physics models to this previously unexplored regime and show clear evidence for contributions from both the one- and two-halo terms, but no statistically significant evidence for contributions from diffuse, unbound gas outside of collapsed halos. We also show that the amplitude of the signal depends rather sensitively on the amplitude of fluctuations (σ{sub 8}) and the matter density (Ω{sub m}), scaling as σ{sub 8}{sup 6.1}Ω{sub m}{sup 1.5} at ℓ = 1000. We constrain the degenerate combination σ{sub 8}(Ω{sub m}/0.282){sup 0.26} = 0.824±0.029, a result that is in less tension with primordial CMB constraints than some recent t

  8. Gravitational Lenses in the Classroom

    ERIC Educational Resources Information Center

    Ros, Rosa M.

    2008-01-01

    It is not common to introduce current astronomy in school lessons. This article presents a set of experiments about gravitational lenses. It is normal to simulate them by means of computers, but it is very simple to simulate similar effects using a drinking glass full of liquid or using only the glass base. These are, of course, cheap and easy…

  9. Optics Demonstrations Using Cylindrical Lenses

    ERIC Educational Resources Information Center

    Ivanov, Dragia; Nikolov, Stefan

    2015-01-01

    In this paper we consider the main properties of cylindrical lenses and propose several demonstrational experiments that can be performed with them. Specifically we use simple glasses full of water to demonstrate some basic geometrical optics principles and phenomena. We also present some less standard experiments that can be performed with such…

  10. Gravitational Lensing of Supernova Neutrinos

    SciTech Connect

    Mena, Olga; Mocioiu, Irina; Quigg, Chris; /Fermilab

    2006-10-01

    The black hole at the center of the galaxy is a powerful lens for supernova neutrinos. In the very special circumstance of a supernova near the extended line of sight from Earth to the galactic center, lensing could dramatically enhance the neutrino flux at Earth and stretch the neutrino pulse.

  11. Irlen Lenses and Reading Difficulties.

    ERIC Educational Resources Information Center

    Hoyt, Creig S.

    1990-01-01

    The article reviews three studies (EC 600 064-066) evaluating the effectiveness of using Irlen tinted lenses with reading-disabled persons. The studies are individually critiqued, and recommendations are offered concerning the methodology of further research. Stressed is the need to determine whether a specific syndrome of scotopic sensitivity…

  12. Cosmic superstring gravitational lensing phenomena: Predictions for networks of (p,q) strings

    SciTech Connect

    Shlaer, Benjamin; Wyman, Mark

    2005-12-15

    The unique, conical space-time created by cosmic strings brings about distinctive gravitational lensing phenomena. The variety of these distinctive phenomena is increased when the strings have nontrivial mutual interactions. In particular, when strings bind and create junctions, rather than intercommute, the resulting configurations can lead to novel gravitational lensing patterns. In this brief note, we use exact solutions to characterize these phenomena, the detection of which would be strong evidence for the existence of complex cosmic string networks of the kind predicted by string theory-motivated cosmic string models. We also correct some common errors in the lensing phenomenology of straight cosmic strings.

  13. Astrophysical uses of CMB lensing

    NASA Astrophysics Data System (ADS)

    Das, Sudeep

    The future of Cosmic Microwave Background (CMB) research lies in exploiting the arcminute scale secondary anisotropies which encode information about the late time interaction of the CMB photons with the structure in the Universe. A specific form of such interaction is the gravitational lensing of the CMB photons by intervening matter--the main topic of this thesis. Upcoming experiments like the Atacama Cosmology Telescope (ACT) and PLANCK will measure these anisotropies with unprecedented resolution and sensitivity. In four separate papers, laid out as four chapters in this thesis, we present new techniques to model and analyze such high resolution data and explore the implications of such measurements on Cosmology, mainly in the context of CMB lensing. The first chapter describes a novel and accurate method for simulating high resolution lensed CMB maps by ray-tracing through a large scale structure simulation. This method does not adopt the flat sky approximation and retains information from large angular scales in the dark matter distribution. Maps simulated through this method will be instrumental in developing the detection and analysis techniques for CMB lensing in high resolution CMB experiments like ACT. In the second chapter, we describe a new and efficient method for measuring the power spectrum of arcminute resolution CMB maps. At these resolutions, the CMB power spectrum is extremely red and is prone to aliasing of power due to hard edges and point source masks. By combining two new techniques, namely, prewhitening and the adaptive multitaper method, we show that these problems can be efficiently remedied and the uncertainties in the final power spectrum estimate can be reduced by several factors over those obtainable by the now standard methods. These techniques will be also useful for estimating higher order statistics from the maps, like the ones related to the detection of CMB lensing and its cross-correlation with large scale structure tracers. In

  14. A Test of a Strong Ground Motion Prediction Methodology for the 7 September 1999, Mw=6.0 Athens Earthquake

    SciTech Connect

    Hutchings, L; Ioannidou, E; Voulgaris, N; Kalogeras, I; Savy, J; Foxall, W; Stavrakakis, G

    2004-08-06

    We test a methodology to predict the range of ground-motion hazard for a fixed magnitude earthquake along a specific fault or within a specific source volume, and we demonstrate how to incorporate this into probabilistic seismic hazard analyses (PSHA). We modeled ground motion with empirical Green's functions. We tested our methodology with the 7 September 1999, Mw=6.0 Athens earthquake, we: (1) developed constraints on rupture parameters based on prior knowledge of earthquake rupture processes and sources in the region; (2) generated impulsive point shear source empirical Green's functions by deconvolving out the source contribution of M < 4.0 aftershocks; (3) used aftershocks that occurred throughout the area and not necessarily along the fault to be modeled; (4) ran a sufficient number of scenario earthquakes to span the full variability of ground motion possible; (5) found that our distribution of synthesized ground motions span what actually occurred and their distribution is realistically narrow; (6) determined that one of our source models generates records that match observed time histories well; (7) found that certain combinations of rupture parameters produced ''extreme'' ground motions at some stations; (8) identified that the ''best fitting'' rupture models occurred in the vicinity of 38.05{sup o} N 23.60{sup o} W with center of rupture near 12 km, and near unilateral rupture towards the areas of high damage, and this is consistent with independent investigations; and (9) synthesized strong motion records in high damage areas for which records from the earthquake were not recorded. We then developed a demonstration PSHA for a source region near Athens utilizing synthesized ground motion rather that traditional attenuation. We synthesized 500 earthquakes distributed throughout the source zone likely to have Mw=6.0 earthquakes near Athens. We assumed an average return period of 1000 years for this magnitude earthquake in the particular source zone

  15. Thermal lensing of laser materials

    NASA Astrophysics Data System (ADS)

    Davis, Mark J.; Hayden, Joseph S.

    2014-10-01

    This paper focuses on the three main effects that can induce wave-front distortion due to thermal lensing in laser gain media: 1) thermo-optic (dn/dT); 2) stress-optic; and 3) surface deformation (e.g., "end-bulging" of a laser rod). Considering the simple case of a side-pumped cylindrical rod which is air- or water-cooled along its length, the internal temperature distribution has long been known to assume a simple parabolic profile. Resulting from this are two induced refractive index variations due to thermo-optic and stress-optic effects that also assume a parabolic profile, but generally not of the same magnitude, nor even of the same sign. Finally, a small deformation on the rod ends can induce a small additional lensing contribution. We had two goals in this study: a) use finite-element simulations to verify the existing analytical expressions due to Koechner1 and Foster and Osterink; and b) apply them to glasses from the SCHOTT laser glass portfolio. The first goal was a reaction to more recent work by Chenais et al. who claimed Koechner made an error in his analysis with regard to thermal stress, throwing into doubt conclusions within studies since 1970 which made use of his equations. However, our re-analysis of their derivations, coupled with our FE modeling, confirmed that the Koechner and Foster and Osterink treatments are correct, and that Chenais et al. made mistakes in their derivation of the thermally-induced strain. Finally, for a nominal laser rod geometry, we compared the thermally-induced optical distortions in LG-680, LG-750, LG-760, LG-770, APG-1, and APG-2. While LG-750, -760, and -770 undergo considerable thermo-optic lensing, their stress-optic lensing is nearly of the same magnitude but of opposite sign, leading to a small total thermal lensing signature.

  16. Magnified Weak Lensing Cross Correlation Tomography

    SciTech Connect

    Ulmer, Melville P., Clowe, Douglas I.

    2010-11-30

    nights on 4-m class telescopes, which gives concrete evidence of strong community support for this project. The WLT technique is based on the dependence of the gravitational shear signal on the angular diameter distances between the observer, the lens, and the lensed galaxy to measure cosmological parameters. By taking the ratio of measured shears of galaxies with different redshifts around the same lens, one obtains a measurement of the ratios of the angular diameter distances involved. Making these observations over a large range of lenses and background galaxy redshifts will measure the history of the expansion rate of the universe. Because this is a purely geometric measurement, it is insensitive to any form of evolution of objects or the necessity to understand the physics in the early universe. Thus, WLT was identified by the Dark Energy Task Force as perhaps the best method to measure the evolution of DE. To date, however, the conjecture of the DETF has not been experimentally verified, but will be by the proposed project. The primary reason for the lack of tomography measurements is that one must have an exceptional data-set to attempt the measurement. One needs both extremely good seeing (or space observations) in order to minimize the point spread function smearing corrections on weak lensing shear measurements and deep, multi-color data, from B to z, to measure reliable photometric redshifts of the background galaxies being lensed (which are typically too faint to obtain spectroscopic redshifts). Because the entire process from multi-drizzling the HST images, and then creating shear maps, to gathering the necessary ground based observations, to generating photo-zs and then carrying out the tomography is a complicated task, until the creation of our team, nobody has taken the time to connect all the levels of expertise necessary to carry out this project based on HST archival data. Our data are being used in 2 Ph.D. theses. Kellen Murphy, at Ohio University, is

  17. Weak shear study of galaxy clusters by simulated gravitational lensing

    NASA Astrophysics Data System (ADS)

    Coss, David

    Gravitational lensing has been simulated for numerical galaxy clusters in order to characterize the effects of substructure and shape variations of dark matter halos on the weak lensing properties of clusters. In order to analyze realistic galaxy clusters, 6 high-resolution Adaptive Refinement Tree N-body simulations of clusters with hydrodynamics are used, in addition to a simulation of one group undergoing a merger. For each cluster, the three-dimensional particle distribution is projected perpendicular to three orthogonal lines of sight, providing 21 projected mass density maps. The clusters have representative concentration and mass values for clusters in the concordance cosmology. Two gravitational lensing simulation methods are presented. In the first method, direct integration is used to calculate deflection angles. To overcome computational constraints inherent in this method, a distributed computing project was created for parallel computation. In addition to its use in gravitational lensing simulation, a description of the setup and function of this distributed computing project is presented as an alternative to in-house computing clusters, which has the added benefit of public enrollment in science and low cost. In the second method, shear maps are created using a fast Fourier transform method. From these shear maps, the effects of substructure and shape variation are related to observational gravitational lensing studies. Average shear in regions less than and greater than half of the virial radius demonstrates distinct dispersion, varying by 24% from the mean among the 21 maps. We estimate the numerical error in shear calculations to be of the order of 5%. Therefore, this shear dispersion is a reliable consequence of shape dispersion, correlating most strongly with the ratio of smallest-to-largest principal axis lengths of a cluster isodensity shell. On the other hand, image ellipticities, which are of great importance in mass reconstruction, are shown

  18. 75 FR 53971 - Guidance for Industry and Food and Drug Administration Staff; Impact-Resistant Lenses: Questions...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-02

    ...The Food and Drug Administration (FDA) is announcing the availability of the guidance entitled ``Impact-Resistant Lenses: Questions and Answers.'' This guidance document answers manufacturer, importer, and consumer questions on impact-resistant lenses, including questions on test procedures, lens testing apparatus, record maintenance, and exemptions to...

  19. Weak Gravitational Lensing from Regular Bardeen Black Holes

    NASA Astrophysics Data System (ADS)

    Ghaffarnejad, Hossein; niad, Hassan

    2016-03-01

    In this article we study weak gravitational lensing of regular Bardeen black hole which has scalar charge g and mass m. We investigate the angular position and magnification of non-relativistic images in two cases depending on the presence or absence of photon sphere. Defining dimensionless charge parameter q= {g}/{2m} we seek to disappear photon sphere in the case of |q|>{24√5}/{125} for which the space time metric encounters strongly with naked singularities. We specify the basic parameters of lensing in terms of scalar charge by using the perturbative method and found that the parity of images is different in two cases: (a) The strongly naked singularities is present in the space time. (b) singularity of space time is weak or is eliminated (the black hole lens).

  20. Cosmic variance of the galaxy cluster weak lensing signal

    NASA Astrophysics Data System (ADS)

    Gruen, D.; Seitz, S.; Becker, M. R.; Friedrich, O.; Mana, A.

    2015-06-01

    Intrinsic variations of the projected density profiles of clusters of galaxies at fixed mass are a source of uncertainty for cluster weak lensing. We present a semi-analytical model to account for this effect, based on a combination of variations in halo concentration, ellipticity and orientation, and the presence of correlated haloes. We calibrate the parameters of our model at the 10 per cent level to match the empirical cosmic variance of cluster profiles at M_{200m}≈ 10^{14}ldots 10^{15} h^{-1}{ M_{⊙}}, z = 0.25…0.5 in a cosmological simulation. We show that weak lensing measurements of clusters significantly underestimate mass uncertainties if intrinsic profile variations are ignored, and that our model can be used to provide correct mass likelihoods. Effects on the achievable accuracy of weak lensing cluster mass measurements are particularly strong for the most massive clusters and deep observations (with ≈20 per cent uncertainty from cosmic variance alone at M_{200m}≈ 10^{15} h^{-1}{ M_{⊙}} and z = 0.25), but significant also under typical ground-based conditions. We show that neglecting intrinsic profile variations leads to biases in the mass-observable relation constrained with weak lensing, both for intrinsic scatter and overall scale (the latter at the 15 per cent level). These biases are in excess of the statistical errors of upcoming surveys and can be avoided if the cosmic variance of cluster profiles is accounted for.

  1. Gravitational lens equation for embedded lenses; magnification and ellipticity

    SciTech Connect

    Chen, B.; Kantowski, R.; Dai, X.

    2011-10-15

    We give the lens equation for light deflections caused by point mass condensations in an otherwise spatially homogeneous and flat universe. We assume the signal from a distant source is deflected by a single condensation before it reaches the observer. We call this deflector an embedded lens because the deflecting mass is part of the mean density. The embedded lens equation differs from the conventional lens equation because the deflector mass is not simply an addition to the cosmic mean. We prescribe an iteration scheme to solve this new lens equation and use it to compare our results with standard linear lensing theory. We also compute analytic expressions for the lowest order corrections to image amplifications and distortions caused by incorporating the lensing mass into the mean. We use these results to estimate the effect of embedding on strong lensing magnifications and ellipticities and find only small effects, <1%, contrary to what we have found for time delays and for weak lensing, {approx}5%.

  2. Gravitational lensing analysis of the Kilo-Degree Survey

    NASA Astrophysics Data System (ADS)

    Kuijken, Konrad; Heymans, Catherine; Hildebrandt, Hendrik; Nakajima, Reiko; Erben, Thomas; de Jong, Jelte T. A.; Viola, Massimo; Choi, Ami; Hoekstra, Henk; Miller, Lance; van Uitert, Edo; Amon, Alexandra; Blake, Chris; Brouwer, Margot; Buddendiek, Axel; Conti, Ian Fenech; Eriksen, Martin; Grado, Aniello; Harnois-Déraps, Joachim; Helmich, Ewout; Herbonnet, Ricardo; Irisarri, Nancy; Kitching, Thomas; Klaes, Dominik; La Barbera, Francesco; Napolitano, Nicola; Radovich, Mario; Schneider, Peter; Sifón, Cristóbal; Sikkema, Gert; Simon, Patrick; Tudorica, Alexandru; Valentijn, Edwin; Verdoes Kleijn, Gijs; van Waerbeke, Ludovic

    2015-12-01

    The Kilo-Degree Survey (KiDS) is a multi-band imaging survey designed for cosmological studies from weak lensing and photometric redshifts. It uses the European Southern Observatory VLT Survey Telescope with its wide-field camera OmegaCAM. KiDS images are taken in four filters similar to the Sloan Digital Sky Survey ugri bands. The best seeing time is reserved for deep r-band observations. The median 5σ limiting AB magnitude is 24.9 and the median seeing is below 0.7 arcsec. Initial KiDS observations have concentrated on the Galaxy and Mass Assembly (GAMA) regions near the celestial equator, where extensive, highly complete redshift catalogues are available. A total of 109 survey tiles, 1 square degree each, form the basis of the first set of lensing analyses of halo properties of GAMA galaxies. Nine galaxies per square arcminute enter the lensing analysis, for an effective inverse shear variance of 69 arcmin-2. Accounting for the shape measurement weight, the median redshift of the sources is 0.53. KiDS data processing follows two parallel tracks, one optimized for weak lensing measurement and one for accurate matched-aperture photometry (for photometric redshifts). This technical paper describes the lensing and photometric redshift measurements (including a detailed description of the Gaussian aperture and photometry pipeline), summarizes the data quality and presents extensive tests for systematic errors that might affect the lensing analyses. We also provide first demonstrations of the suitability of the data for cosmological measurements, and describe our blinding procedure for preventing confirmation bias in the scientific analyses. The KiDS catalogues presented in this paper are released to the community through http://kids.strw.leidenuniv.nl.

  3. IDCS J1426.5+3508: Weak Lensing Analysis of a Massive Galaxy Cluster at z = 1.75

    NASA Astrophysics Data System (ADS)

    Mo, Wenli; Gonzalez, Anthony; Jee, M. James; Massey, Richard; Rhodes, Jason; Brodwin, Mark; Eisenhardt, Peter; Marrone, Daniel P.; Stanford, S. A.; Zeimann, Gregory R.

    2016-02-01

    We present a weak lensing study of the galaxy cluster IDCS J1426.5+3508 at z = 1.75, which is the highest-redshift strong lensing cluster known and the most distant cluster for which a weak lensing analysis has been undertaken. Using F160W, F814W, and F606W observations with the Hubble Space Telescope, we detect tangential shear at 2σ significance. Fitting a Navarro–Frenk–White mass profile to the shear with a theoretical median mass-concentration relation, we derive a mass {M}200,{crit}={2.3}-1.4+2.1× {10}14 M⊙. This mass is consistent with previous mass estimates from the Sunyaev–Zel’dovich (SZ) effect, X-ray, and strong lensing. The cluster lies on the local SZ–weak lensing mass scaling relation observed at low redshift, indicative of minimal evolution in this relation.

  4. Weak Lensing Analysis of Massive Galaxy Cluster IDCS J1426.5+3508 at z=1.75

    NASA Astrophysics Data System (ADS)

    Mo, Wenli; Gonzalez, Anthony H.; Jee, Myungkook J.; Massey, Richard; Rhodes, Jason; Brodwin, Mark; Eisenhardt, Peter R.; Marrone, Daniel P.; Stanford, S. Adam; Zeimann, Gregory

    2016-01-01

    We present a weak lensing study of the galaxy cluster IDCS J1426.5+3508 at z=1.75, which is the highest redshift strong lensing cluster known and the most distant cluster for which a weak lensing analysis has been undertaken. Using F160W, F814W, and F606W observations with the Hubble Space Telescope, we detect tangential shear at 2σ significance. Fitting a Navarro-Frenk-White mass profile to the shear with a theoretical median mass-concentration relation, we derive a mass consistent with previous mass estimates from the Sunyaev-Zel'dovich (SZ) effect, X-ray, and strong lensing. The cluster lies on the local SZ-weak lensing mass scaling relation observed at low redshift, indicative of minimal evolution in this relation.

  5. Rigorous noise test and calibration check of strong-motion instrumentation at the Conrad Observatory in Austria.

    NASA Astrophysics Data System (ADS)

    Steiner, R.; Costa, G.; Lenhardt, W.; Horn, N.; Suhadolc, P.

    2012-04-01

    In the framework of the European InterregIV Italy/Austria project: "HAREIA - Historical and Recent Earthquakes in Italy and Austria" the Central Institute for Meteorology and Geodynamics (ZAMG) and Mathematic and Geosciences Department of University of Trieste (DMG) are upgrading the transfrontier seismic network of South-Eastern Alps with new 12 accelerometric stations to enhance the strong motion instrument density near the Austria/Italy border. Various public institutions of the provinces Alto Adige (Bolzano Province), Veneto (ARPAV) and Friuli Venezia Giulia (Regional Civil Defense) in Italy and in the Austrian province of Tyrol are involved in the project. The site selection was carried out to improve the present local network geometry thus meeting the needs of public Institutions in the involved regions. In Tyrol and Alto Adige some strategic buildings (hospitals and public buildings) have been selected, whereas in Veneto and Friuli Venezia Giulia the sites are in the free field, mainly located near villages. The instruments will be installed in an innovative box, designed by ZAMG, that provides electric and water isolation. The common choice regarding the instrument selection has been the new Kinemetrics Basalt ® accelerograph to guarantee homogeneity with the already installed instrumentation and compatibility with the software already in use at the different seismic institutions in the area. Prior to deployment the equipment was tested at the Conrad Observatory and a common set-up has been devised. The Conrad Observatory, seismically particularly quiet, permits to analyze both the sensor and the acquisition system noise. The instruments were connected to the network and the data sent in real-time to the ZAMG data center in Vienna and the DMG data center in Trieste. The data have been collected in the database and analyzed using signal processing modules PQLX and Matlab. The data analysis of the recordings at the ultra-quiet Conrad Observatory pointed out

  6. Conceptual design of hollow electron lenses for beam halo control in the Large Hadron Collider

    SciTech Connect

    Stancari, Giulio; Previtali, Valentina; Valishev, Alexander; Bruce, Roderik; Redaelli, Stefano; Rossi, Adriana; Salvachua Ferrando, Belen

    2014-06-26

    Collimation with hollow electron beams is a technique for halo control in high-power hadron beams. It is based on an electron beam (possibly pulsed or modulated in intensity) guided by strong axial magnetic fields which overlaps with the circulating beam in a short section of the ring. The concept was tested experimentally at the Fermilab Tevatron collider using a hollow electron gun installed in one of the Tevatron electron lenses. We are proposing a conceptual design for applying this technique to the Large Hadron Collider at CERN. A prototype hollow electron gun for the LHC was built and tested. The expected performance of the hollow electron beam collimator was based on Tevatron experiments and on numerical tracking simulations. Halo removal rates and enhancements of halo diffusivity were estimated as a function of beam and lattice parameters. Proton beam core lifetimes and emittance growth rates were checked to ensure that undesired effects were suppressed. Hardware specifications were based on the Tevatron devices and on preliminary engineering integration studies in the LHC machine. Required resources and a possible timeline were also outlined, together with a brief discussion of alternative halo-removal schemes and of other possible uses of electron lenses to improve the performance of the LHC.

  7. Compound Refractive Lenses for Thermal Neutron Applications

    SciTech Connect

    Gary, Charles K.

    2013-11-12

    This project designed and built compound refractive lenses (CRLs) that are able to focus, collimate and image using thermal neutrons. Neutrons are difficult to manipulate compared to visible light or even x rays; however, CRLs can provide a powerful tool for focusing, collimating and imaging neutrons. Previous neutron CRLs were limited to long focal lengths, small fields of view and poor resolution due to the materials available and manufacturing techniques. By demonstrating a fabrication method that can produce accurate, small features, we have already dramatically improved the focal length of thermal neutron CRLs, and the manufacture of Fresnel lens CRLs that greatly increases the collection area, and thus efficiency, of neutron CRLs. Unlike a single lens, a compound lens is a row of N lenslets that combine to produce an N-fold increase in the refraction of neutrons. While CRLs can be made from a variety of materials, we have chosen to mold Teflon lenses. Teflon has excellent neutron refraction, yet can be molded into nearly arbitrary shapes. We designed, fabricated and tested Teflon CRLs for neutrons. We demonstrated imaging at wavelengths as short as 1.26 ? with large fields of view and achieved resolution finer than 250 μm which is better than has been previously shown. We have also determined designs for Fresnel CRLs that will greatly improve performance.

  8. GLAMER - II. Multiple-plane gravitational lensing

    NASA Astrophysics Data System (ADS)

    Petkova, Margarita; Metcalf, R. Benton; Giocoli, Carlo

    2014-12-01

    We present an extension to multiple planes of the gravitational lensing code GLAMER. The method entails projecting the mass in the observed light-cone on to a discrete number of lens planes and inverse ray-shooting from the image to the source plane. The mass on each plane can be represented as haloes, simulation particles, a projected mass map extracted form a numerical simulation or any combination of these. The image finding is done in a source-oriented fashion, where only regions of interest are iteratively refined on an initially coarse image plane grid. The calculations are performed in parallel on shared memory machines. The code is able to handle different types of analytic haloes (NFW, NSIE, power law, etc.), haloes extracted from numerical simulations and clusters constructed from semi-analytic models (MOKA). Likewise, there are several different options for modelling the source(s) which can be distributed throughout the light-cone. The distribution of matter in the light-cone can be either taken from a pre-existing N-body numerical simulations, from halo catalogues, or are generated from an analytic mass function. We present several tests of the code and demonstrate some of its applications such as generating mock images of galaxy and galaxy cluster lenses.

  9. Tomography and weak lensing statistics

    SciTech Connect

    Munshi, Dipak; Coles, Peter; Kilbinger, Martin E-mail: peter.coles@astro.cf.ac.uk

    2014-04-01

    We provide generic predictions for the lower order cumulants of weak lensing maps, and their correlators for tomographic bins as well as in three dimensions (3D). Using small-angle approximation, we derive the corresponding one- and two-point probability distribution function for the tomographic maps from different bins and for 3D convergence maps. The modelling of weak lensing statistics is obtained by adopting a detailed prescription for the underlying density contrast that involves hierarchal ansatz and lognormal distribution. We study the dependence of our results on cosmological parameters and source distributions corresponding to the realistic surveys such as LSST and DES. We briefly outline how photometric redshift information can be incorporated in our results. We also show how topological properties of convergence maps can be quantified using our results.

  10. Extinction Curves of Lensing Galaxies

    NASA Astrophysics Data System (ADS)

    Elíasdóttir, Árdís

    2006-09-01

    Dust extinction causes light from distant sources to be dimmed on itsway to the observer. In cosmological studies, such as SN Ia studies,it is of great importance that the effects of dust extinction becorrectly accounted for. However, although dust properties, andhence extinction, are expected to vary with redshift, not very muchis known about the extinction properties of high redshift galaxies.This is because the methods traditionally used to study extinctioncurves are only applicable for the most nearby galaxies. Studyinggravitationally lensed quasars is an emerging method of studying thedust extinction of high redshift galaxies. I will present an ESO VLTstudy of 10 such lensing galaxies, with redshifts up to 1. The 10systems display varying amount and type of extinction, with thedoubly imaged quasar B1152+199 showing the greatest extinction with A(V)=2.4 and R_V=2.1 for a Galactic type extinction law.

  11. DARK MATTER SUBSTRUCTURE DETECTION USING SPATIALLY RESOLVED SPECTROSCOPY OF LENSED DUSTY GALAXIES

    SciTech Connect

    Hezaveh, Yashar; Holder, Gilbert; Dalal, Neal; Kuhlen, Michael; Marrone, Daniel; Murray, Norman; Vieira, Joaquin

    2013-04-10

    We investigate how strong lensing of dusty, star-forming galaxies (DSFGs) by foreground galaxies can be used as a probe of dark matter halo substructure. We find that spatially resolved spectroscopy of lensed sources allows dramatic improvements to measurements of lens parameters. In particular, we find that modeling of the full, three-dimensional (angular position and radial velocity) data can significantly facilitate substructure detection, increasing the sensitivity of observables to lower mass subhalos. We carry out simulations of lensed dusty sources observed by early ALMA (Cycle 1) and use a Fisher matrix analysis to study the parameter degeneracies and mass detection limits of this method. We find that even with conservative assumptions, it is possible to detect galactic dark matter subhalos of {approx}10{sup 8} M{sub Sun} with high significance in most lensed DSFGs. Specifically, we find that in typical DSFG lenses, there is a {approx}55% probability of detecting a substructure with M > 10{sup 8} M{sub Sun} with more than 5{sigma} detection significance in each lens, if the abundance of substructure is consistent with previous lensing results. The full ALMA array, with its significantly enhanced sensitivity and resolution, should improve these estimates considerably. Given the sample of {approx}100 lenses provided by surveys such as the South Pole Telescope, our understanding of dark matter substructure in typical galaxy halos is poised to improve dramatically over the next few years.

  12. Studying functional properties of hydrogel and silicone-hydrogel contact lenses with PALS, MIR and Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Filipecki, J.; Sitarz, M.; Kocela, A.; Kotynia, K.; Jelen, P.; Filipecka, K.; Gaweda, M.

    2014-10-01

    Determination of free volume holes of the hydrogel and silicone-hydrogel polymer contact lenses were investigated. Two types of polymer contact lenses were used as materials: the first is a hydrogel contact lenses Proclear family (Omafilcon A), while the second is a silicone-hydrogel contact lens of the family Biofinity (Comfilcon A). Positron annihilation lifetime spectroscopy PALS was used to characterize geometrical sizes and fraction of the free volume holes in the investigated samples. There is a clear difference in the free volume sizes and their fractions between silicone-hydrogel and polymer hydrogel contact lenses which in turn are connected with oxygen permeability in these lenses. Apart from that, spectroscopic (middle infrared) MIR and Raman examinations were carried out in order to demonstrate the differences of the water content in the test contact lenses.

  13. Luminous and Dark Matter Profiles from Galaxies to Clusters: Bridging the Gap with Group-scale Lenses

    NASA Astrophysics Data System (ADS)

    Newman, Andrew B.; Ellis, Richard S.; Treu, Tommaso

    2015-11-01

    Observations of strong gravitational lensing, stellar kinematics, and larger-scale tracers enable accurate measures of the distribution of dark matter (DM) and baryons in massive early-type galaxies (ETGs). While such techniques have been applied to galaxy-scale and cluster-scale lenses, the paucity of intermediate-mass systems with high-quality data has precluded a uniform analysis of mass-dependent trends. With the aim of bridging this gap, we present new observations and analyses of 10 group-scale lenses at < z> =0.36, characterized by Einstein radii {θ }{{Ein}}=2\\buildrel{\\prime\\prime}\\over{.} 5-5\\buildrel{\\prime\\prime}\\over{.} 1 and a mean halo mass of {M}200={10}14.0 {M}ȯ . We measure a mean concentration c200 = 5.0 ± 0.8 consistent with unmodified cold dark matter halos. By combining our data with other lens samples, we analyze the mass structure of ETGs in 1013 {M}ȯ –1015 {M}ȯ halos using homogeneous techniques. We show that the slope of the total density profile γtot within the effective radius depends on the stellar surface density, as demonstrated previously, but also on the halo mass. We analyze these trends using halo occupation models and resolved stellar kinematics with the goal of testing the universality of the DM profile. Whereas the central galaxies of clusters require a shallow inner DM density profile, group-scale lenses are consistent with a Navarro–Frenk–White profile or one that is slightly contracted. The largest uncertainties arise from the sample size and likely radial gradients in stellar populations. We conclude that the net effect of baryons on the DM distribution may not be universal, but more likely varies with halo mass due to underlying trends in star formation efficiency and assembly history.

  14. Gravitational lensing in plasmic medium

    NASA Astrophysics Data System (ADS)

    Bisnovatyi-Kogan, G. S.; Tsupko, O. Yu.

    2015-07-01

    The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered.

  15. Gravitational lensing in plasmic medium

    SciTech Connect

    Bisnovatyi-Kogan, G. S. Tsupko, O. Yu.

    2015-07-15

    The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered.

  16. Full-field and scanning microtomography based on parabolic refractive x-ray lenses

    NASA Astrophysics Data System (ADS)

    Schroer, C. G.; Kuhlmann, M.; Günzler, T. F.; Benner, B.; Kurapova, O.; Patommel, J.; Lengeler, B.; Roth, S. V.; Gehrke, R.; Snigirev, A.; Snigireva, I.; Stribeck, N.; Almendarez-Camarillo, A.; Beckmann, F.

    2006-08-01

    Hard x-ray full field and scanning microscopy both greatly benefit from recent advances in x-ray optics. In full field microscopy, for instance, rotationally parabolic refractive x-ray lenses can be used as objective lens in a hard x-ray microscope, magnifying an object onto a detector free of distortion. Using beryllium as lens material, a hard x-ray optical resolution of about 100 nm has been obtained in a field of view of more than 500 micrometers. Further improvement of the spatial resolution to below 50 nm is expected. By reconstructing the sample from a series of micrographs recorded from different perspectives, tomographic imaging with a resolution well below one micrometer was achieved. The technique is demonstrated using a microchip as test sample. In scanning microscopy and tomography, the sample is scanned through a hard x-ray microbeam. Different hard x-ray analytical techniques can be exploited as contrast mechanism, such as x-ray fluorescence, absorption, or scattering. In tomographic scanning mode, they yield for example local elemental, chemical, or structural information from inside a specimen. At synchrotron radiation sources, a small and intensive microbeam can be generated by imaging the source onto the sample position in a strongly reducing geometry, e.g., by parabolic refractive x-ray lenses. With nanofocusing refractive x-ray lenses, a lateral beam size of 50 nm was reached. As an example for scanning tomography, we consider tomographic small angle x-ray scattering (SAXS-tomography), reconstructing a series of SAXS patterns related to small volume elements inside a polymer rod made by injection moulding.

  17. Organizational Culture and Effectiveness in Higher Education: A Test of the "Culture Type" and "Strong Culture" Hypotheses.

    ERIC Educational Resources Information Center

    Smart, John C.; St. John, Edward P.

    1996-01-01

    The relative merits of two prominent lines of inquiry into the linkage between organizational culture and effectiveness (culture type and strong culture hypotheses) were studied with 334 colleges and universities. Findings support both approaches and suggest that alternative culture types are differentially effective on different performance…

  18. Equatorial gravitational lensing by accelerating and rotating black hole with NUT parameter

    NASA Astrophysics Data System (ADS)

    Sharif, M.; Iftikhar, Sehrish

    2016-01-01

    This paper is devoted to study equatorial gravitational lensing in accelerating and rotating black hole with a NUT parameter in the strong field limit. For this purpose, we first calculate null geodesic equation using the Hamilton-Jacobi separation method. We then numerically obtain deflection angle and deflection coefficients which depend on acceleration and spin parameter of the black hole. We also investigate observables in the strong field limit by taking the example of a black hole in the center of galaxy. It is concluded that acceleration parameter has a significant effect on the strong field lensing in the equatorial plane.

  19. Difference Imaging of Lensed Quasar Candidates in the Sloan Digital Sky Survey Supernova Survey Region

    NASA Astrophysics Data System (ADS)

    Lacki, Brian C.; Kochanek, Christopher S.; Stanek, Krzysztof Z.; Inada, Naohisa; Oguri, Masamune

    2009-06-01

    Difference imaging provides a new way to discover gravitationally lensed quasars because few nonlensed sources will show spatially extended, time variable flux. We test the method on the fields of lens candidates in the Sloan Digital Sky Survey (SDSS) Supernova Survey region from the SDSS Quasar Lens Search (SQLS) and one serendipitously discovered lensed quasar. Starting from 20,536 sources, including 49 SDSS quasars, 32 candidate lenses/lensed images, and one known lensed quasar, we find that 174 sources including 35 SDSS quasars, 16 candidate lenses/lensed images, and the known lensed quasar are nonperiodic variable sources. We can measure the spatial structure of the variable flux for 119 of these variable sources and identify only eight as candidate extended variables, including the known lensed quasar. Only the known lensed quasar appears as a close pair of sources on the difference images. Inspection of the remaining seven suggests they are false positives, and only two were spectroscopically identified quasars. One of the lens candidates from the SQLS survives our cuts, but only as a single image instead of a pair. This indicates a false positive rate of order ~1/4000 for the method, or given our effective survey area of order 0.82 deg2, ~5 per deg2 in the SDSS Supernova Survey. The fraction of quasars not found to be variable and the false positive rate would both fall if we had analyzed the full, later data releases for the SDSS fields. While application of the method to the SDSS is limited by the resolution, depth, and sampling of the survey, several future surveys such as Pan-STARRS, LSST, and SNAP will significantly improve on these limitations.

  20. Inhibition of Methylglyoxal-Mediated Protein Modification in Glyoxalase I Overexpressing Mouse Lenses

    PubMed Central

    Gangadhariah, Mahesha H.; Mailankot, Maneesh; Reneker, Lixing; Nagaraj, Ram H.

    2010-01-01

    Objective. Here we tested the role of Glo I in the prevention of advanced glycation end product (AGE) formation in transgenic mouse lenses. Methods. A transgenic animal line that expressed high levels of human Glo I in the lens was developed from the C57B6 mouse strain. The role of Glo I in the inhibition of MGO-AGE formation was tested in organ-cultured lenses. Results. Organ culture of Wt and Glo I lenses with 5 mM D, L-glyceraldehyde (GLD) enhanced MGO by 29-fold and 17-fold in Wt lenses and Glo I lenses, respectively. Argpyrimidine levels were 192 ± 73 pmoles/mg protein, and hydroimidazolone levels were 22 ± 0.7 units/μg protein in GLD-incubated Wt lenses. In Glo I lenses, formation of AGEs was significantly inhibited; the argpyrimidine levels were 82 ± 18 pmoles/mg protein, and the HI levels were 2.6 ± 2.3 units/μg protein. Incubation of Wt lens proteins with 5 mM ribose for 7 days resulted in the formation of pentosidine. However, the levels were substantially higher in Glo I lens proteins incubated with ribose. Conclusion. Our study provides direct evidence that Glo I activity plays an important role in the regulation of AGE synthesis in the lens; while Glo I activity blocks the formation of MGO-AGEs, it might promote the formation of sugar-derived AGEs. PMID:20671953

  1. Gravitational lenses and dark matter - Theory

    NASA Technical Reports Server (NTRS)

    Gott, J. Richard, III

    1987-01-01

    Theoretical models are presented for guiding the application of gravitational lenses to probe the characteristics of dark matter in the universe. Analytical techniques are defined for quantifying the mass associated with lensing galaxies (in terms of the image separation), determining the quantity of dark mass of the lensing bodies, and estimating the mass density of the lenses. The possibility that heavy halos are made of low mass stars is considered, along with the swallowing of central images of black holes or cusps in galactic nuclei and the effects produced on a lensed quasar image by nonbaryonic halos. The observable effects of dense groups and clusters and the characteristics of dark matter strings are discussed, and various types of images which are possible due to lensing phenomena and position are described.

  2. CMB lensing and primordial non-Gaussianity

    SciTech Connect

    Hanson, Duncan; Smith, Kendrick M.; Challinor, Anthony; Liguori, Michele

    2009-10-15

    We study the effects of gravitational lensing on the estimation of non-Gaussianity from the bispectrum of the CMB temperature anisotropies. We find that the effect of lensing on the bispectrum may qualitatively be described as a smoothing of the acoustic features analogous to the temperature power spectrum. In contrast to previous results, for a Planck-like experiment which is cosmic-variance limited to l{sub max}=2000, we find that lensing causes no significant degradation of our ability to constrain the non-Gaussianity amplitude f{sub NL} for both local and equilateral configurations, provided that the biases due to the cross correlation between the lensing potential and the integrated-Sachs-Wolfe contribution to the CMB temperature are adequately understood. With numerical simulations, we also verify that low-order Taylor approximations to the lensed bispectrum and integrated-Sachs-Wolfe-lensing biases are accurate.

  3. Reducing systematic error in weak lensing cluster surveys

    SciTech Connect

    Utsumi, Yousuke; Miyazaki, Satoshi; Hamana, Takashi; Geller, Margaret J.; Kurtz, Michael J.; Fabricant, Daniel G.; Dell'Antonio, Ian P.; Oguri, Masamune

    2014-05-10

    Weak lensing provides an important route toward collecting samples of clusters of galaxies selected by mass. Subtle systematic errors in image reduction can compromise the power of this technique. We use the B-mode signal to quantify this systematic error and to test methods for reducing this error. We show that two procedures are efficient in suppressing systematic error in the B-mode: (1) refinement of the mosaic CCD warping procedure to conform to absolute celestial coordinates and (2) truncation of the smoothing procedure on a scale of 10'. Application of these procedures reduces the systematic error to 20% of its original amplitude. We provide an analytic expression for the distribution of the highest peaks in noise maps that can be used to estimate the fraction of false peaks in the weak-lensing κ-signal-to-noise ratio (S/N) maps as a function of the detection threshold. Based on this analysis, we select a threshold S/N = 4.56 for identifying an uncontaminated set of weak-lensing peaks in two test fields covering a total area of ∼3 deg{sup 2}. Taken together these fields contain seven peaks above the threshold. Among these, six are probable systems of galaxies and one is a superposition. We confirm the reliability of these peaks with dense redshift surveys, X-ray, and imaging observations. The systematic error reduction procedures we apply are general and can be applied to future large-area weak-lensing surveys. Our high-peak analysis suggests that with an S/N threshold of 4.5, there should be only 2.7 spurious weak-lensing peaks even in an area of 1000 deg{sup 2}, where we expect ∼2000 peaks based on our Subaru fields.

  4. Direct shear mapping - a new weak lensing tool

    NASA Astrophysics Data System (ADS)

    de Burgh-Day, C. O.; Taylor, E. N.; Webster, R. L.; Hopkins, A. M.

    2015-08-01

    We have developed a new technique called direct shear mapping (DSM) to measure gravitational lensing shear directly from observations of a single background source. The technique assumes the velocity map of an unlensed, stably rotating galaxy will be rotationally symmetric. Lensing distorts the velocity map making it asymmetric. The degree of lensing can be inferred by determining the transformation required to restore axisymmetry. This technique is in contrast to traditional weak lensing methods, which require averaging an ensemble of background galaxy ellipticity measurements, to obtain a single shear measurement. We have tested the efficacy of our fitting algorithm with a suite of systematic tests on simulated data. We demonstrate that we are in principle able to measure shears as small as 0.01. In practice, we have fitted for the shear in very low redshift (and hence unlensed) velocity maps, and have obtained null result with an error of ±0.01. This high-sensitivity results from analysing spatially resolved spectroscopic images (i.e. 3D data cubes), including not just shape information (as in traditional weak lensing measurements) but velocity information as well. Spirals and rotating ellipticals are ideal targets for this new technique. Data from any large Integral Field Unit (IFU) or radio telescope is suitable, or indeed any instrument with spatially resolved spectroscopy such as the Sydney-Australian-Astronomical Observatory Multi-Object Integral Field Spectrograph (SAMI), the Atacama Large Millimeter/submillimeter Array (ALMA), the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) and the Square Kilometer Array (SKA).

  5. Disentangling dark sector models using weak lensing statistics

    NASA Astrophysics Data System (ADS)

    Giocoli, Carlo; Metcalf, R. Benton; Baldi, Marco; Meneghetti, Massimo; Moscardini, Lauro; Petkova, Margarita

    2015-09-01

    We perform multiplane ray tracing using the GLAMER gravitational lensing code within high-resolution light-cones extracted from the CoDECS simulations: a suite of cosmological runs featuring a coupling between dark energy and cold dark matter (CDM). We show that the presence of the coupling is evident not only in the redshift evolution of the normalization of the convergence power spectrum, but also in differences in non-linear structure formation with respect to ΛCDM. Using a tomographic approach under the assumption of a ΛCDM cosmology, we demonstrate that weak lensing measurements would result in a σ8 value that changes with the source redshift if the true underlying cosmology is a coupled dark energy (cDE) one. This provides a generic null test for these types of models. We also find that different models of cDE can show either an enhanced or a suppressed correlation between convergence maps with differing source redshifts as compared to ΛCDM. This would provide a direct way to discriminate between different possible realizations of the cDE scenario. Finally, we discuss the impact of the coupling on several lensing observables for different source redshifts and angular scales with realistic source redshift distributions for current ground-based and future space-based lensing surveys.

  6. Galaxy Cluster Center Detection Methods with Weak Lensing

    NASA Astrophysics Data System (ADS)

    Simet, Melanie

    2013-01-01

    The precise location of galaxy cluster centers is a persistent problem in weak lensing mass estimates and in interpretations of clusters in a cosmological context. Misidentification of centers, either because a well-defined center does not exist or because candidate centers are incorrectly identified or ranked, leads to systematic underestimates of cluster masses. Weak lensing provides a potential lever on this issue by directly probing the distribution of dark matter. We test methods of determining cluster centers directly from weak lensing data and examine the effects of such self-calibration on the measured masses. Drawing on lensing data from the Sloan Digital Sky Survey Stripe 82, a 275 square degree region of coadded data in the Southern Galactic Cap, together with a catalog of MaxBCG clusters, we show that halo substructure as well as shape noise and stochasticity in galaxy positions limit the precision of such a self-calibration (in the context of Stripe 82, to ~500 h-1 kpc or larger) and bias the mass estimates around these points to a level that is likely unacceptable for the purposes of making cosmological measurements. In cases where other center identification methods fail, however, the method may still be useful to distinguish between competing options.

  7. Efficacy of multipurpose solutions for rigid gas permeable lenses.

    PubMed

    Boost, Maureen; Cho, Pauline; Lai, Sindy

    2006-09-01

    The use of multipurpose solutions for cleaning and disinfecting rigid gas permeable lenses has replaced single purpose solutions, but there are no reports of the efficacy of these multipurpose solutions, or of the effects of storage conditions on their disinfecting capacities. This study investigated activity against four bacterial and two fungal species, and the effects of storage in a refrigerator, at room temperature, at elevated temperature in both dry and humid conditions and with exposure to sunlight. The disinfecting solutions were challenged with the micro-organisms initially upon opening and then at 2-weekly intervals up to 12 weeks after being stored under the different conditions. Solutions were opened daily to simulate use. One solution failed to meet Food and Drug Administration (FDA) criteria to reduce numbers of bacteria by three log dilutions and of fungi by one log dilution. Storage reduced activity of all solutions over the 12-week period, but not below the requirements of the FDA. Storage in the refrigerator tended to reduce disinfecting capacity more quickly. Multipurpose solutions for rigid gas permeable (RGP) lenses lose activity over the 3 months recommended time of use but remain satisfactory for use over this time in the conditions tested. Practitioners need to remind patients to replace their solutions regularly and should advise against storage in the refrigerator. Multipurpose solutions for RGP lenses have simplified cleaning and disinfecting processes and the current formulations have improved disinfecting capacity compared to former disinfecting solutions, which is particularly important for wearers of orthokeratology lenses. PMID:16918771

  8. Ultraviolet radiation for the sterilization of contact lenses

    SciTech Connect

    Gritz, D.C.; Lee, T.Y.; McDonnell, P.J.; Shih, K.; Baron, N. )

    1990-10-01

    Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials were minimally affected by exposure to 300 hours of UV-B. Ultraviolet light is an effective germicidal agent but is injurious to soft lens polymers; its possible utility in the sterilization of RGP lenses and lens cases deserves further study.

  9. Weak lensing of the primary CMB bispectrum

    SciTech Connect

    Cooray, Asantha; Sarkar, Devdeep; Serra, Paolo

    2008-06-15

    The bispectrum of cosmic microwave background (CMB) anisotropies is a well-known probe of the non-Gaussianity of primordial perturbations. Just as the intervening large-scale structure modifies the CMB angular power spectrum through weak gravitational lensing, the CMB primary bispectrum generated at the last scattering surface is also modified by lensing. We discuss the lensing modification to the CMB bispectrum and show that lensing leads to an overall decrease in the amplitude of the primary bispectrum at multipoles of interest between 100 and 2000 through additional smoothing introduced by lensing. Since weak lensing is not accounted for in current estimators of the primordial non-Gaussianity parameter, the existing measurements of f{sub NL} of the local model with WMAP out to l{sub max}{approx}750 is biased low by about 6%. For a high resolution experiment such as Planck, the lensing modification to the bispectrum must be properly included when attempting to estimate the primordial non-Gaussianity or the bias will be at the level of 30%. For Planck, weak lensing increases the minimum detectable value for the non-Gaussianity parameter of the local type f{sub NL} to 7 from the previous estimate of about 5 without lensing. The minimum detectable value of f{sub NL} for a cosmic variance limited experiment is also increased from less than 3 to {approx}5.

  10. The Alvarez and Lohmann refractive lenses revisited.

    PubMed

    Barbero, Sergio

    2009-05-25

    Alvarez and Lohmann lenses are variable focus optical devices based on lateral shifts of two lenses with cubic-type surfaces. I analyzed the optical performance of these types of lenses computing the first order optical properties (applying wavefront refraction and propagation) without the restriction of the thin lens approximation, and the spot diagram using a ray tracing algorithm. I proposed an analytic and numerical method to select the most optimum coefficients and the specific configuration of these lenses. The results show that Lohmann composite lens is slightly superior to Alvarez one because the overall thickness and optical aberrations are smaller. PMID:19466190

  11. cluster-lensing: Tools for calculating properties and weak lensing profiles of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Ford, Jes

    2016-05-01

    The cluster-lensing package calculates properties and weak lensing profiles of galaxy clusters. Implemented in Python, it includes cluster mass-richness and mass-concentration scaling relations, and NFW halo profiles for weak lensing shear, the differential surface mass density ΔΣ(r), and for magnification, Σ(r). Optionally the calculation will include the effects of cluster miscentering offsets.

  12. Relative performance of soft contact lenses having lathe-cut posterior surfaces with and without additional polishing.

    PubMed

    O'Brien, C; Charman, W N

    2006-05-01

    After a preliminary investigation of the effects of tool feed rate and spindle speed on the surface roughness of unhydrated, lathe-cut polymacon surfaces, a laboratory and clinical comparison was made between lenses with identical parameters except that the lathe-cut posterior surface was left unpolished in the "test" lenses and was polished in the "control" lenses. The lenses had moulded anterior surfaces. Laboratory comparisons included surface roughness, lens power and its uniformity across the surface. Double-blind clinical trials over 4-hour (27 subjects) and 1-month (10 subjects) periods, involved one eye of each subject wearing a "test" lens and the other, a "control" lens. No clinically significant differences were found between the results for the test and control lenses. It is concluded that today's lathing technology makes a final polishing stage unnecessary. PMID:16701199

  13. Use of the Humphrey Lens Analyzer for off-axis measurements of spectacle lenses.

    PubMed

    Atchison, D A; Kris, M; Sheedy, J E; Bailey, I L

    1991-04-01

    Automated focimeters can be used to make quick, precise measurements of off-axis power and prismatic effects corresponding to an eye rotating behind a spectacle lens. An automated focimeter, the Humphrey Lens Analyzer, was assessed in this regard. The Humphrey Lens Analyzer can be used to give a valid measure of off-axis power of lenses with low power, but not of lenses with moderate to higher power (greater than 3 D). For 3 D spherical lenses discrepancies of the order of 0.1 D occur at 30 degrees rotation, and 6 D spheres give discrepancies of 0.5 D at the same rotation. Small discrepancies were found for measurements of prism. The Humphrey Lens Analyzer was also used in a mode where the lens being tested is rotated about the center of curvature of its back surface. This is the mode often used to assess aberrations and prism of progressive-addition lenses. In this mode, the instrument provides reasonable accuracy in estimating off-axis power corresponding to eye rotation for lenses with low power, but not for lenses with moderate to higher power (greater than 3 D). However, it provides accurate values of the variation in off-axis surface power for low powered lenses with aspheric front surfaces. There were considerable systematic errors associated with the measurement of prism. A simple raytracing method was developed to predict the results of measurements with the Humphrey Lens Analyzer. Predictions of off-axis power were good when lenses were rotated about a position corresponding to the center-of-rotation of an eye, but were poorer when lenses were rotated about the center of curvature of their back surfaces. Predictions of primatic efforts were good in both situations. A method by which the Humphrey Lens Analyzer should provide an accurate measurement of off-axis powers corresponding to eye rotation behind a spectacle lens is described, but has not been tested. PMID:2052286

  14. Systematic errors in strong lens modeling

    NASA Astrophysics Data System (ADS)

    Johnson, Traci Lin; Sharon, Keren; Bayliss, Matthew B.

    2015-08-01

    The lensing community has made great strides in quantifying the statistical errors associated with strong lens modeling. However, we are just now beginning to understand the systematic errors. Quantifying these errors is pertinent to Frontier Fields science, as number counts and luminosity functions are highly sensitive to the value of the magnifications of background sources across the entire field of view. We are aware that models can be very different when modelers change their assumptions about the parameterization of the lensing potential (i.e., parametric vs. non-parametric models). However, models built while utilizing a single methodology can lead to inconsistent outcomes for different quantities, distributions, and qualities of redshift information regarding the multiple images used as constraints in the lens model. We investigate how varying the number of multiple image constraints and available redshift information of those constraints (ex., spectroscopic vs. photometric vs. no redshift) can influence the outputs of our parametric strong lens models, specifically, the mass distribution and magnifications of background sources. We make use of the simulated clusters by M. Meneghetti et al. and the first two Frontier Fields clusters, which have a high number of multiply imaged galaxies with spectroscopically-measured redshifts (or input redshifts, in the case of simulated clusters). This work will not only inform upon Frontier Field science, but also for work on the growing collection of strong lensing galaxy clusters, most of which are less massive and are capable of lensing a handful of galaxies, and are more prone to these systematic errors.

  15. Strong Interaction

    SciTech Connect

    Karsch, F.; Vogelsang, V.

    2009-09-29

    We will give here an overview of our theory of the strong interactions, Quantum Chromo Dynamics (QCD) and its properties. We will also briefly review the history of the study of the strong interactions, and the discoveries that ultimately led to the formulation of QCD. The strong force is one of the four known fundamental forces in nature, the others being the electromagnetic, the weak and the gravitational force. The strong force, usually referred to by scientists as the 'strong interaction', is relevant at the subatomic level, where it is responsible for the binding of protons and neutrons to atomic nuclei. To do this, it must overcome the electric repulsion between the protons in an atomic nucleus and be the most powerful force over distances of a few fm (1fm=1 femtometer=1 fermi=10{sup -15}m), the typical size of a nucleus. This property gave the strong force its name.

  16. Constraining gravity at the largest scales through CMB lensing and galaxy velocities

    NASA Astrophysics Data System (ADS)

    Pullen, Anthony R.; Alam, Shadab; He, Siyu; Ho, Shirley

    2016-08-01

    We demonstrate a new method to constrain gravity on the largest cosmological scales by combining measurements of cosmic microwave background (CMB) lensing and the galaxy velocity field. EG is a statistic, constructed from a gravitational lensing tracer and a measure of velocities such as redshift-space distortions (RSD), that can discriminate between gravity models while being independent of clustering bias and σ8. While traditionally, the lensing field for EG has been probed through galaxy lensing, CMB lensing has been proposed as a more robust tracer of the lensing field for EG at higher redshifts while avoiding intrinsic alignments. We perform the largest-scale measurement of EG ever, up to 150 Mpc h-1, by cross-correlating the Planck CMB lensing map with the Sloan Digital Sky Survey III (SDSS-III) CMASS galaxy sample and combining this with our measurement of the CMASS auto-power spectrum and the RSD parameter β. We report EG(z = 0.57) = 0.243 ± 0.060 (stat) ± 0.013 (sys), a measurement in tension with the general relativity (GR) prediction at a level of 2.6σ. Note that our EG measurement deviates from GR only at scales greater than 80 Mpc h-1, scales which have not been probed by previous EG tests. Upcoming surveys, which will provide an order-of-magnitude reduction in statistical errors, can significantly constrain alternative gravity models when combined with better control of systematics.

  17. Difference Imaging of Lensed Quasar Candidates inthe SDSS Supernova Survey Region

    SciTech Connect

    Lacki, Brian C.; Kochanek, Christopher S.; Stanek, Krzysztof Z.; Inada, Naohisa; Oguri, Masamune

    2008-02-04

    Difference imaging provides a new way to discover gravitationally lensed quasars because few non-lensed sources will show spatially extended, time variable flux. We test the method on lens candidates in the Sloan Digital Sky Survey (SDSS) Supernova Survey region from the SDSS Quasar Lens Search (SQLS) and their surrounding fields. Starting from 20768 sources, including 49 SDSS quasars and 36 candidate lenses/lensed images, we find that 21 sources including 15 SDSS QSOs and 7 candidate lenses/lensed images are non-periodic variable sources. We can measure the spatial structure of the variable flux for 18 of these sources and identify only one as a non-point source. This source does not display the compelling spatial structure of the variable flux of known lensed quasars, so we reject it as a lens candidate. None of the lens candidates from the SQLS survive our cuts. Given our effective survey area of order 0.71 square degrees, this indicates a false positive rate of order one per square degree for the method. The fraction of quasars not found to be variable and the false positive rate should both fall if we analyze the full, later data releases for the SDSS fields. While application of the method to the SDSS is limited by the resolution, depth, and sampling of the survey, several future surveys such as Pan-STARRS, LSST, and SNAP will avoid these limitations.

  18. Electrically thin flat lenses and reflectors.

    PubMed

    Ruphuy, Miguel; Siddiqui, Omar; Ramahi, Omar M

    2015-09-01

    We introduce electrically thin dielectric lenses and reflectors that focus a plane wave based on the principles of phase compensation and constructive wave interference. Phase compensation is achieved by arranging thin rectangular slabs having different dielectric permittivity according to a permittivity profile obtained through analytic design equations. All incident rays parallel to the optical axis converge to a focal point with equalized optical paths resulting in constructive interference. Plane wave simulations indicate strong focusing, even in the presence of impedance mismatch between free space and the dielectric layers composing the lens. We demonstrate focusing at 9.45 GHz using a lens fabricated with commercially available dielectric materials. In addition to focusing, the flat lens proposed here demonstrates relatively high power gain at the focal point. We also present a flat reflector based on the same concept. We believe that the proposed dielectric lens and reflector are strong candidates to replace heavy metallic dishes and reflectors used in a variety of applications, especially satellites. PMID:26367439

  19. Weak lensing by galaxy troughs

    NASA Astrophysics Data System (ADS)

    Gruen, Daniel

    2016-06-01

    Galaxy troughs, i.e. underdensities in the projected galaxy field, are a weak lensing probe of the low density Universe with high signal-to-noise ratio. I present measurements of the radial distortion of background galaxy images and the de-magnification of the CMB by troughs constructed from Dark Energy Survey and Sloan Digital Sky Survey galaxy catalogs. With high statistical significance and a relatively robust modeling, these probe gravity in regimes of density and scale difficult to access for conventional statistics.

  20. Gravitational Lensing Extends SETI Range

    NASA Astrophysics Data System (ADS)

    Factor, Richard

    Microwave SETI (The Search for Extraterrestrial Intelligence) focuses on two primary strategies, the "Targeted Search" and the "All-Sky Survey." Although the goal of both strategies is the unequivocal discovery of a signal transmitted by intelligent species outside our solar system, they pursue the strategies in very different manners and have vastly different requirements. This chapter introduces Gravitational Lensing SETI (GL-SETI), a third strategy. Its goal is the unequivocal discovery of an extraterrestrial signal, with equipment and data processing requirements that are substantially different from the commonly-used strategies. This strategy is particularly suitable for use with smaller radio telescopes and has budgetary requirements suitable for individual researchers.

  1. Tritan colour contrast sensitivity function in refractive multifocal intraocular lenses

    PubMed Central

    Pieh, S.; Hanselmayer, G.; Lackner, B.; Marvan, P.; Grechenig, A.; Weghaupt, H.; Vass, C.; Skorpik, C.

    2001-01-01

    AIMS—To compare tritan colour contrast sensitivity (CCS), without and with glare, in patients with refractive multifocal intraocular lenses (IOLs) and with monofocal intraocular lenses.
METHODS—Tritan CCS was determined (Moorfields Vision System, CH Electronics) in 15 eyes (14 patients, 75.7 (±6.6) years) with a refractive multifocal IOL (Allergan SA 40N) and in 11 eyes (10 patients, 73.7 (±6.4) years) with a monofocal IOL (Allergan SI 40 NB). Measurements were made monocularly under mesopic conditions at a distance of 2 metres from the monitor with best distance refraction plus 0.5 D at 0.5, 1, 3, 6, 11.4, and 22.8 cycles per degree (cpd). The test was then repeated for the multifocal IOLs, adding minus 2.5 D to the best distance refraction to force the patient to use the near focus. Both lenses were also investigated under glare conditions with the same set-up and using the brightness acuity tester (BAT).
RESULTS—The tritan CCS function without glare in multifocal lenses through the distance focus was nearly identical to that through the near focus. The following statistically significant differences were measured: the CCS function without glare for the multifocal lens was worse at 0.5 cpd and 1.0 cpd than that of the monofocal lens. In CCS testing of the multifocal group with glare at 6 cpd, the results through the distance focus were better than the results through the near focus. For the CCS function with glare, the values for the distance focus in the multifocal lens were worse than the values for the monofocal lens at 0.5 cpd and 1 cpd. In CCS testing with glare through the near focus and CCS testing through the monofocal lens, the monofocal lens performed better at 0.5 cpd, 1 cpd, 3 cpd, and 6 cpd.
CONCLUSION—Refractive multifocal intraocular lenses influence tritan CCS function compared to monofocal lenses.

 PMID:11423455

  2. A comparison of cosmological models using time delay lenses

    SciTech Connect

    Wei, Jun-Jie; Wu, Xue-Feng; Melia, Fulvio E-mail: xfwu@pmo.ac.cn

    2014-06-20

    The use of time-delay gravitational lenses to examine the cosmological expansion introduces a new standard ruler with which to test theoretical models. The sample suitable for this kind of work now includes 12 lens systems, which have thus far been used solely for optimizing the parameters of ΛCDM. In this paper, we broaden the base of support for this new, important cosmic probe by using these observations to carry out a one-on-one comparison between competing models. The currently available sample indicates a likelihood of ∼70%-80% that the R {sub h} = ct universe is the correct cosmology versus ∼20%-30% for the standard model. This possibly interesting result reinforces the need to greatly expand the sample of time-delay lenses, e.g., with the successful implementation of the Dark Energy Survey, the VST ATLAS survey, and the Large Synoptic Survey Telescope. In anticipation of a greatly expanded catalog of time-delay lenses identified with these surveys, we have produced synthetic samples to estimate how large they would have to be in order to rule out either model at a ∼99.7% confidence level. We find that if the real cosmology is ΛCDM, a sample of ∼150 time-delay lenses would be sufficient to rule out R {sub h} = ct at this level of accuracy, while ∼1000 time-delay lenses would be required to rule out ΛCDM if the real universe is instead R {sub h} = ct. This difference in required sample size reflects the greater number of free parameters available to fit the data with ΛCDM.

  3. Preschool Social-Emotional Skills Training: A Controlled Pilot Test of the Making Choices and Strong Families Programs

    ERIC Educational Resources Information Center

    Conner, Natalie W.; Fraser, Mark W.

    2011-01-01

    Objective: The purpose of this study was to pilot test a multicomponent program designed to prevent aggressive behavior in preschool children. The first program component was comprised of social-emotional skills training. It focused on improving the social information processing and emotional-regulation skills of children. The second component was…

  4. Using compound kinoform hard-x-ray lenses to exceed the critical angle limit.

    PubMed

    Evans-Lutterodt, K; Stein, A; Ablett, J M; Bozovic, N; Taylor, A; Tennant, D M

    2007-09-28

    We have fabricated and tested a compound lens consisting of an array of four kinoform lenses for hard x-ray photons of 11.3 keV. Our data demonstrate that it is possible to exceed the critical angle limit by using multiple lenses, while retaining lens function, and this suggests a route to practical focusing optics for hard x-ray photons with nanometer scale resolution and below. PMID:17930597

  5. Using Compound Kinoform Hard-X-Ray Lenses to Exceed the Critical Angle Limit

    SciTech Connect

    Evans-Lutterodt, K.; Stein, A.; Ablett, J. M.; Bozovic, N.; Taylor, A.; Tennant, D. M.

    2007-09-28

    We have fabricated and tested a compound lens consisting of an array of four kinoform lenses for hard x-ray photons of 11.3 keV. Our data demonstrate that it is possible to exceed the critical angle limit by using multiple lenses, while retaining lens function, and this suggests a route to practical focusing optics for hard x-ray photons with nanometer scale resolution and below.

  6. 20(S)-protopanaxadiol, an active ginseng metabolite, exhibits strong antidepressant-like effects in animal tests.

    PubMed

    Xu, Changjiang; Teng, Jijun; Chen, Weidong; Ge, Qiang; Yang, Zhiqi; Yu, Chunying; Yang, Zirong; Jia, William

    2010-12-01

    Ginseng has been used for mood adjustment in traditional Chinese medicine for thousands of years. Our previous study has shown that, total ginsenosides, the major pharmacologically functional ingredients of ginseng, possess antidepressant activity. In the present study, we hypothesized that an intestinal metabolite of ginseng, 20(S)-protopanaxadiol (code name S111), as a post metabolism compound (PMC) of ingested ginsenosides, may be responsible for the antidepressant activity of ginseng. To test this hypothesis, antidepressant-like activity of orally given S111 was measured in animal tests including tail suspension test, forced swimming test and rat olfactory bulbectomy depression model. In all those tests, S111 demonstrated antidepressant-like activity as potent as fluoxetine. S111 treated bulbectomy animals had higher levels of monoamine neurotransmitters in the brain and in vitro reuptake assay showed that S111 had a mild inhibitory effect. Furthermore, S111 but not fluoxetine significantly reduced brain oxidative stress and down-regulated serum corticosterone concentration in bulbectomy animals. No disturbance to central nervous system (CNS) normal functions were found in S111 treated animals. These results suggest that the ginseng active metabolite S111 is a potential antidepressant. Since the monoamine reuptake activity of this compound is rather weak, it remains to be investigated whether its antidepressant-like effect is by mechanisms that are different from current antidepressants. Furthermore, this study has demonstrated that post metabolism compounds (PMCs) of herb medicines such as S111 may be a novel source for drug discovery from medicinal herbs. PMID:20647027

  7. Gravitational Lensing in TeVe S

    NASA Astrophysics Data System (ADS)

    Chiu, Mu-Chen; Ko, Chung-Ming; Tian, Yong

    Gravitational Lensing is an important tool to understand the "missing mass" problem, especially for Modified Gravity. Recently, Bekenstein proposed a relativistic gravitation theory for Modified Newtonian Dynamics (MOND) paradigm which resolves the "missing mass" problem well on abnormal dynamical behaviors in extragalactic region. Our work follow Bekenstein's approach to investigating gravitational lensing to get theoretical prediction.

  8. Bayesian Inference of CMB Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Anderes, Ethan; Wandelt, Benjamin D.; Lavaux, Guilhem

    2015-08-01

    The Planck satellite, along with several ground-based telescopes, has mapped the cosmic microwave background (CMB) at sufficient resolution and signal-to-noise so as to allow a detection of the subtle distortions due to the gravitational influence of the intervening matter distribution. A natural modeling approach is to write a Bayesian hierarchical model for the lensed CMB in terms of the unlensed CMB and the lensing potential. So far there has been no feasible algorithm for inferring the posterior distribution of the lensing potential from the lensed CMB map. We propose a solution that allows efficient Markov Chain Monte Carlo sampling from the joint posterior of the lensing potential and the unlensed CMB map using the Hamiltonian Monte Carlo technique. The main conceptual step in the solution is a re-parameterization of CMB lensing in terms of the lensed CMB and the “inverse lensing” potential. We demonstrate a fast implementation on simulated data, including noise and a sky cut, that uses a further acceleration based on a very mild approximation of the inverse lensing potential. We find that the resulting Markov Chain has short correlation lengths and excellent convergence properties, making it promising for applications to high-resolution CMB data sets in the future.

  9. Offset lenses add versatility to phototypesetting machine

    NASA Technical Reports Server (NTRS)

    James, A. M.

    1966-01-01

    Offset lenses facilitate the composition of inputs of other than straight baseline characters on the Photon phototypesetting machine. A number of lenses in the turret are mounted in an offset pattern that causes characters projected through them to fall on the photographic paper in the magazine above and below the baseline.

  10. Hydromechanical Pumping Test for the Joint Estimation of Hydraulic and Poroelastic Parameters in a Strongly Heterogeneous Glaciofluvial Aquifer

    NASA Astrophysics Data System (ADS)

    Illman, W. A.; Berg, S. J.

    2009-12-01

    The coupling of hydraulic and geomechanical processes is critical in predicting the magnitude of earthquakes, understanding the effect of hydrofracturing on groundwater resources, designing nuclear waste repositories, predicting land subsidence due to pumping and its reversal through water injection. Therefore, the knowledge of hydraulic and geomechanical properties of soil and rock (collectively known as hydromechanical properties) are crucial for understanding and predicting the behavior of complex geological systems. In this study, we jointly estimated hydraulic and poroelastic parameters (i.e., shear modulus) from pumping test data that exhibited “reverse water level fluctuations” known as the Noordbergum effect observed in aquitards adjacent to pumped aquifers. This was performed by coupling BIOT2, a finite element two-dimensional axisymmetric groundwater model that considers the poroelastic effect with the parameter estimation code PEST. We first tested our inverse approach using a synthetic data set with known parameters. Results of the synthetic case showed that for simple layered systems, it was possible to accurately reproduce both the hydraulic properties and the shear modulus. We then applied the inverse approach to a set of pumping test data collected at the North Campus Research Site (NCRS) located at the University of Waterloo in Ontario, Canada. Based on the knowledge of stratigraphy determined from cores, the field site was simplified for modeling purposes as a 5-layer system. Parameter estimation was performed using two different approaches: 1) matching data individually from each observation port, and 2) matching data simultaneously from all observation ports. The estimated hydraulic parameters and shear modulus were compared to those obtained from other means at the site and to those from the literature. This comparison yielded good agreement. The results collectively suggest that the joint estimation of hydraulic and poroelastic parameters

  11. Aberrations in asymmetrical electron lenses.

    PubMed

    Fitzgerald, J P S; Word, R C; Könenkamp, R

    2012-08-01

    Starting from well established knowledge in light-optics we explore the question if electron-optical aberration can be improved in asymmetrical electron lenses. We show that spherical as well as chromatic aberration coefficients are reduced in asymmetric electrostatic einzel lenses when the center electrode is moved away from the center position towards the entrance electrode. Relative improvements up to 40% for both the chromatic and the spherical aberration coefficients can be obtained. We use analytical and numerical calculations to confirm this result for exemplary cases of a lens with fixed length and working distance. The agreement of the two calculation methods is very good. We then derive an estimate for the electron-optical aberration coefficients from light-optics. The derived expressions for chromatic and spherical aberrations are somewhat simpler than the ones derived from electron-optics as they involve integrals only over the electrostatic potential, not over the electron paths. The estimated formulas still agree well with the electron optical calculations. Overall, we are tempted to suggest that the enormous knowledge base of light optics can provide considerable guidance for electron-optical applications. PMID:22206603

  12. Time delay in Swiss cheese gravitational lensing

    SciTech Connect

    Chen, B.; Kantowski, R.; Dai, X.

    2010-08-15

    We compute time delays for gravitational lensing in a flat {Lambda} dominated cold dark matter Swiss cheese universe. We assume a primary and secondary pair of light rays are deflected by a single point mass condensation described by a Kottler metric (Schwarzschild with {Lambda}) embedded in an otherwise homogeneous cosmology. We find that the cosmological constant's effect on the difference in arrival times is nonlinear and at most around 0.002% for a large cluster lens; however, we find differences from time delays predicted by conventional linear lensing theory that can reach {approx}4% for these large lenses. The differences in predicted delay times are due to the failure of conventional lensing to incorporate the lensing mass into the mean mass density of the universe.

  13. MODEL-FREE MULTI-PROBE LENSING RECONSTRUCTION OF CLUSTER MASS PROFILES

    SciTech Connect

    Umetsu, Keiichi

    2013-05-20

    Lens magnification by galaxy clusters induces characteristic spatial variations in the number counts of background sources, amplifying their observed fluxes and expanding the area of sky, the net effect of which, known as magnification bias, depends on the intrinsic faint-end slope of the source luminosity function. The bias is strongly negative for red galaxies, dominated by the geometric area distortion, whereas it is mildly positive for blue galaxies, enhancing the blue counts toward the cluster center. We generalize the Bayesian approach of Umetsu et al. for reconstructing projected cluster mass profiles, by incorporating multiple populations of background sources for magnification-bias measurements and combining them with complementary lens-distortion measurements, effectively breaking the mass-sheet degeneracy and improving the statistical precision of cluster mass measurements. The approach can be further extended to include strong-lensing projected mass estimates, thus allowing for non-parametric absolute mass determinations in both the weak and strong regimes. We apply this method to our recent CLASH lensing measurements of MACS J1206.2-0847, and demonstrate how combining multi-probe lensing constraints can improve the reconstruction of cluster mass profiles. This method will also be useful for a stacked lensing analysis, combining all lensing-related effects in the cluster regime, for a definitive determination of the averaged mass profile.

  14. Properties of Galaxy Dark Matter Halos from Weak Lensing

    NASA Astrophysics Data System (ADS)

    Hoekstra, Henk; Yee, H. K. C.; Gladders, Michael D.

    2004-05-01

    We present the results of a study of weak lensing by galaxies based on 45.5 deg2 of RC-band imaging data from the Red-Sequence Cluster Survey (RCS). We define a sample of lenses with 19.5lensing detection of the flattening of galaxy dark matter halos. We use a simple model in which the ellipticity of the halo is f times the observed ellipticity of the lens. We find a best-fit value of f=0.77+0.18-0.21, which suggests that the dark matter halos are somewhat rounder than the light distribution. The fact that we detect a significant flattening implies that the halos are well aligned with the light distribution. Given the average ellipticity of the lenses, this implies a halo ellipticity of =0.33+0.07-0.09, in fair agreement with results from numerical simulations of cold dark matter. We note that this result is formally a lower limit to the flattening, since the measurements imply a larger flattening if the halos are not aligned with the light distribution. Alternative theories of gravity (without dark matter) predict an isotropic lensing signal, which is excluded with 99.5% confidence. Hence, our results provide strong support for the existence of dark matter. We also study the average mass profile around the lenses, using a maximum likelihood analysis. We consider two models for the halo mass profile: a truncated isothermal sphere (TIS) and a Navarro-Frenk-White (NFW) profile. We adopt observationally motivated scaling relations between the lens luminosity and the velocity dispersion and the extent of the halo. The TIS model yields a best-fit velocity dispersion of σ=136+/-5+/-3 km s-1 (all errors are 68% confidence limits; the first error bar indicates the statistical uncertainty, whereas the second error bar indicates the systematic error) and a truncation radius s=185+30-28h-1 kpc for a galaxy with a fiducial luminosity of LB=1010h-2LB,solar (under the assumption that

  15. Witnessing the Differential Evolution in Luminosity and Size of Disk Galaxies via Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Bandara, Kaushala; Crampton, D.; Peng, C. Y.; Simard, L.

    2012-01-01

    We take advantage of the magnification in size and flux of a galaxy, provided by gravitational lensing, to analyze the properties of 62 strongly lensed galaxies of the Sloan Lens ACS (SLACS) Survey. The sample of lensed galaxies span a redshift range of 0.20 <= z <= 1.20 with a median redshift of z = 0.61. We use the lens modeling code LENSFIT to derive the luminosities, sizes and Sersic indices of the lensed galaxies. The measured properties of the lensed galaxies show a primarily compact, "disk"-like population with the peaks of the size and Sersic index distributions corresponding to ˜1.50 kpc and n˜1 respectively. Comparison of the SLACS lensed galaxies to a non-lensing, broad-band imaging based survey shows that a lensing survey allows us to probe a galaxy population that is typically ˜ 2 magnitudes fainter. Our analysis allows us to compare the = 0.61 disk galaxy sample (n <= 2.5) to an unprecedented local galaxy sample of 670,131 SDSS galaxies at z ˜ 0.1, which indicates that the evolution of the luminosity-size relation since z ˜ 1 cannot be explained fully in terms of pure size evolution but must be caused by a combination of luminosity and size evolution. Our observations are in excellent agreement with recent numerical simulations of disk galaxies since z ˜ 1 that show evidence of mass-dependent evolution where high-mass disk galaxies (stellar mass > 109 solar masses) evolve more in size and low-mass disk galaxies (stellar mass <= 109 solar masses) evolve more in luminosity. The authors gratefully acknowledge the support from the National Research Council of Canada and NSERC through Discovery grants. CYP is grateful for funding support through the Plaskett Fellowship of the Herzberg Institute of Astrophysics (National Research Council of Canada).

  16. A strategy for finding gravitationally-lensed distant supernovae

    SciTech Connect

    Sullivan, Mark; Ellis, Richard; Nugent, Peter; Smail, Ian; Madau, Piero

    2000-07-17

    Distant Type Ia and II supernovae (SNe) can serve as valuable probes of the history of the cosmic expansion and star formation, and provide important information on their progenitor models. At present, however, there are few observational constraints on the abundance of SNe at high redshifts. A major science driver for the Next Generation Space Telescope (NGST) is the study of very distant supernovae. In this paper we discuss strategies for finding and counting distant SNe by using repeat imaging of super-critical intermediate redshift clusters whose mass distributions are well-constrained via modelling of strongly-lensed features. For a variety of different models for the star formation history and supernova progenitors, we estimate the likelihood of detecting lensed SNe as a function of their redshift. In the case of a survey conducted by HST, we find a high probability of seeing a supernova in a single return visit with either WFPC-2 or ACS, and a much higher probability of detecting examples with z &62; 1 in the lensed case. Most events would represent magnified SNe II at z{approximately}1, and a fraction will be more distant examples. We discuss various ways to classify such events using ground-based infrared photometry. We demonstrate an application of the method using the HST archival data and discuss the case of a possible event found in the rich cluster AC 114 (z=0.31).

  17. SKA Weak Lensing II: Simulated Performance and Survey Design Considerations

    NASA Astrophysics Data System (ADS)

    Bonaldi, Anna; Harrison, Ian; Camera, Stefano; Brown, Michael L.

    2016-08-01

    We construct a pipeline for simulating weak lensing cosmology surveys with the Square Kilometre Array (SKA), taking as inputs telescope sensitivity curves; correlated source flux, size and redshift distributions; a simple ionospheric model; source redshift and ellipticity measurement errors. We then use this simulation pipeline to optimise a 2-year weak lensing survey performed with the first deployment of the SKA (SKA1). Our assessments are based on the total signal-to-noise of the recovered shear power spectra, a metric that we find to correlate very well with a standard dark energy figure of merit. We first consider the choice of frequency band, trading off increases in number counts at lower frequencies against poorer resolution; our analysis strongly prefers the higher frequency Band 2 (950-1760 MHz) channel of the SKA-MID telescope to the lower frequency Band 1 (350-1050 MHz). Best results would be obtained by allowing the centre of Band 2 to shift towards lower frequency, around 1.1 GHz. We then move on to consider survey size, finding that an area of 5,000 square degrees is optimal for most SKA1 instrumental configurations. Finally, we forecast the performance of a weak lensing survey with the second deployment of the SKA. The increased survey size (3π steradian) and sensitivity improves both the signal-to-noise and the dark energy metrics by two orders of magnitude.

  18. Scanning Miniature Microscopes without Lenses

    NASA Technical Reports Server (NTRS)

    Wang, Yu

    2009-01-01

    The figure schematically depicts some alternative designs of proposed compact, lightweight optoelectronic microscopes that would contain no lenses and would generate magnified video images of specimens. Microscopes of this type were described previously in Miniature Microscope Without Lenses (NPO - 20218), NASA Tech Briefs, Vol. 22, No. 8 (August 1998), page 43 and Reflective Variants of Miniature Microscope Without Lenses (NPO 20610), NASA Tech Briefs, Vol. 26, No. 9 (September 1999), page 6a. To recapitulate: In the design and construction of a microscope of this type, the focusing optics of a conventional microscope are replaced by a combination of a microchannel filter and a charge-coupled-device (CCD) image detector. Elimination of focusing optics reduces the size and weight of the instrument and eliminates the need for the time-consuming focusing operation. The microscopes described in the cited prior articles contained two-dimensional CCDs registered with two-dimensional arrays of microchannels and, as such, were designed to produce full two-dimensional images, without need for scanning. The microscopes of the present proposal would contain one-dimensional (line image) CCDs registered with linear arrays of microchannels. In the operation of such a microscope, one would scan a specimen along a line perpendicular to the array axis (in other words, one would scan in pushbroom fashion). One could then synthesize a full two-dimensional image of the specimen from the line-image data acquired at one-pixel increments of position along the scan. In one of the proposed microscopes, a beam of unpolarized light for illuminating the specimen would enter from the side. This light would be reflected down onto the specimen by a nonpolarizing beam splitter attached to the microchannels at their lower ends. A portion of the light incident on the specimen would be reflected upward, through the beam splitter and along the microchannels, to form an image on the CCD. If the

  19. Transmission and gain of singly and doubly focusing refractive x-ray lenses

    NASA Astrophysics Data System (ADS)

    Lengeler, B.; Tümmler, J.; Snigirev, A.; Snigireva, I.; Raven, C.

    1998-12-01

    Multiple refractive lenses with a focal length of 1 to 2 m are a new tool for focusing hard x rays to a spot size in the micrometer range. They may be used for microdiffraction, microfluorescence, and coherent imaging. The lenses may be focusing in one or two dimensions. In this article, we have calculated the transmission and the gain for linear lens arrays, for crossed linear arrays and for doubly focusing lenses with parabolic profile. It is essential to minimize the mass absorption coefficient μ/ρ by choosing low Z materials in order to optimize the transmission. The gain of the lenses can be as high as 5000 and more, i.e., the intensity in the focal spot can be 5000 times higher than that behind a pinhole of size equal to the spot size. In real lenses the gain is smaller and the focal spot is blurred by lens imperfections, by Compton scattering, and by small angle x-ray scattering (SAS). In the present investigation different low Z materials have been tested for SAS. Different linear and crossed linear lenses made of beryllium, boron nitride, pyrographite, plexiglass, polycarbonate, polyoxymethylene, Vespel, and aluminium have been tested for focal spot size, gain, and background. The maximum gain obtained up to now was 13. The focal spot size is slightly larger than the value expected from demagnification of the source size. Possibilities for improving the lens performance are discussed.

  20. Redshift detection of the most distant lensed starbursts

    NASA Astrophysics Data System (ADS)

    Dunne, Loretta; van der Werf, Paul; Massardi, Marcella; White, Glenn; Serjeant, Stephen; Michalowski, Michal; Thompson, Mark; Birkinshaw, Mark; Andreani, Paola; Stevens, Jamie; Omont, Alain; Smith, Matthew; Ivison, Rob; Thomson, Alasdair; Eales, Steve; Ibar, Edo; Benford, Dominic; Dannerbauer, Helmut; Leeuw, Lerothodi; Temi, Pasquale; Negrello, Mattia; Clements, Dave; Bussmann, Shane; Maddox, Steve; De Vis, Pieter; Vlahakis, Catherine; Verma, Aprajita; Dye, Simon; Riechers, Dominik

    2013-10-01

    We propose to obtain redshifts for the four most distant (z_est > 3.8) and luminous galaxies in 90 sq deg of the Herschel-ATLAS southern field. The bright 500 micron fluxes of these sources means they are either gravitationally lensed or are among the rarest, most luminous starbursts in the universe. Creating large and unbiased samples of strong lenses is a key goal for H-ATLAS, allowing us to constrain cosmological parameters and the evolution of dark matter haloes, as well as providing an unprecedented sample of the most actively star forming galaxies in the early universe, able to be studied in exquisite detail thanks to the lensing magnification. The submm photo-z of these objects are 3.8lensing magnification.

  1. CONSTRAINING SOURCE REDSHIFT DISTRIBUTIONS WITH GRAVITATIONAL LENSING

    SciTech Connect

    Wittman, D.; Dawson, W. A.

    2012-09-10

    We introduce a new method for constraining the redshift distribution of a set of galaxies, using weak gravitational lensing shear. Instead of using observed shears and redshifts to constrain cosmological parameters, we ask how well the shears around clusters can constrain the redshifts, assuming fixed cosmological parameters. This provides a check on photometric redshifts, independent of source spectral energy distribution properties and therefore free of confounding factors such as misidentification of spectral breaks. We find that {approx}40 massive ({sigma}{sub v} = 1200 km s{sup -1}) cluster lenses are sufficient to determine the fraction of sources in each of six coarse redshift bins to {approx}11%, given weak (20%) priors on the masses of the highest-redshift lenses, tight (5%) priors on the masses of the lowest-redshift lenses, and only modest (20%-50%) priors on calibration and evolution effects. Additional massive lenses drive down uncertainties as N{sub lens}{sup -1/2}, but the improvement slows as one is forced to use lenses further down the mass function. Future large surveys contain enough clusters to reach 1% precision in the bin fractions if the tight lens-mass priors can be maintained for large samples of lenses. In practice this will be difficult to achieve, but the method may be valuable as a complement to other more precise methods because it is based on different physics and therefore has different systematic errors.

  2. HST Observations of New Class Gravitational Lenses

    NASA Astrophysics Data System (ADS)

    Jackson, Neal

    1995-07-01

    We propose to examine a few of the very best lens candidates from a new gravitational lens survey, the Cosmic Lens All-Sky Survey (CLASS) made with the VLA. We are virtually certain that we have one new lens system (1600+434) and another (1609+655) has a radio configuration which almost invariably indicates gravitational lensing. The other cases are systems which have a high probability of being lenses (statistically we would expect at least 5 of the 10 objects should be lensed, since we have imaged >3000 radio sources and experience shows that 1 in 500 are lensed). All have separations which make them difficult to study from the ground and therefore uniquely suited to the capabilities of the HST. In this investigation we will study 1600+434 and 1609+655 and attempt to image the lensing galaxy. We will image the remainder in an attempt to confirm their lens status (which requires 0.1" resolution imaging typically) and search for lensing galaxies and/or clusters in those found to be lensed systems.

  3. Mesh-free free-form lensing - I. Methodology and application to mass reconstruction

    NASA Astrophysics Data System (ADS)

    Merten, Julian

    2016-09-01

    Many applications and algorithms in the field of gravitational lensing make use of meshes with a finite number of nodes to analyse and manipulate data. Specific examples in lensing are astronomical CCD images in general, the reconstruction of density distributions from lensing data, lens-source plane mapping or the characterization and interpolation of a point spread function. We present a numerical framework to interpolate and differentiate in the mesh-free domain, defined by nodes with coordinates that follow no regular pattern. The framework is based on radial basis functions (RBFs) to smoothly represent data around the nodes. We demonstrate the performance of Gaussian RBF-based, mesh-free interpolation and differentiation, which reaches the sub-percent level in both cases. We use our newly developed framework to translate ideas of free-form mass reconstruction from lensing on to the mesh-free domain. By reconstructing a simulated mock lens we find that strong-lensing only reconstructions achieve <10 per cent accuracy in the areas where these constraints are available but provide poorer results when departing from these regions. Weak-lensing only reconstructions give <10 per cent accuracy outside the strong-lensing regime, but cannot resolve the inner core structure of the lens. Once both regimes are combined, accurate reconstructions can be achieved over the full field of view. The reconstruction of a simulated lens, using constraints that mimics real observations, yields accurate results in terms of surface-mass density, Navarro-Frenk-White profile (NFW) parameters, Einstein radius and magnification map recovery, encouraging the application of this method to real data.

  4. The DES Science Verification weak lensing shear catalogues

    NASA Astrophysics Data System (ADS)

    Jarvis, M.; Sheldon, E.; Zuntz, J.; Kacprzak, T.; Bridle, S. L.; Amara, A.; Armstrong, R.; Becker, M. R.; Bernstein, G. M.; Bonnett, C.; Chang, C.; Das, R.; Dietrich, J. P.; Drlica-Wagner, A.; Eifler, T. F.; Gangkofner, C.; Gruen, D.; Hirsch, M.; Huff, E. M.; Jain, B.; Kent, S.; Kirk, D.; MacCrann, N.; Melchior, P.; Plazas, A. A.; Refregier, A.; Rowe, B.; Rykoff, E. S.; Samuroff, S.; Sánchez, C.; Suchyta, E.; Troxel, M. A.; Vikram, V.; Abbott, T.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Clampitt, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Fausti Neto, A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; March, M.; Martini, P.; Miquel, R.; Mohr, J. J.; Neilsen, E.; Nord, B.; Ogando, R.; Reil, K.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Walker, A. R.; Wechsler, R. H.

    2016-08-01

    We present weak lensing shear catalogues for 139 square degrees of data taken during the Science Verification (SV) time for the new Dark Energy Camera (DECam) being used for the Dark Energy Survey (DES). We describe our object selection, point spread function estimation and shear measurement procedures using two independent shear pipelines, IM3SHAPE and NGMIX, which produce catalogues of 2.12 million and 3.44 million galaxies respectively. We detail a set of null tests for the shear measurements and find that they pass the requirements for systematic errors at the level necessary for weak lensing science applications using the SV data. We also discuss some of the planned algorithmic improvements that will be necessary to produce sufficiently accurate shear catalogues for the full 5-year DES, which is expected to cover 5000 square degrees.

  5. The DES Science Verification Weak Lensing Shear Catalogs

    SciTech Connect

    Jarvis, M.

    2015-07-20

    We present weak lensing shear catalogs for 139 square degrees of data taken during the Science Verification (SV) time for the new Dark Energy Camera (DECam) being used for the Dark Energy Survey (DES). We describe our object selection, point spread function estimation and shear measurement procedures using two independent shear pipelines, IM3SHAPE and NGMIX, which produce catalogs of 2.12 million and 3.44 million galaxies respectively. We also detail a set of null tests for the shear measurements and find that they pass the requirements for systematic errors at the level necessary for weak lensing science applications using the SV data. Furthermore, we discuss some of the planned algorithmic improvements that will be necessary to produce sufficiently accurate shear catalogs for the full 5-year DES, which is expected to cover 5000 square degrees.

  6. The DES Science Verification weak lensing shear catalogues

    NASA Astrophysics Data System (ADS)

    Jarvis, M.; Sheldon, E.; Zuntz, J.; Kacprzak, T.; Bridle, S. L.; Amara, A.; Armstrong, R.; Becker, M. R.; Bernstein, G. M.; Bonnett, C.; Chang, C.; Das, R.; Dietrich, J. P.; Drlica-Wagner, A.; Eifler, T. F.; Gangkofner, C.; Gruen, D.; Hirsch, M.; Huff, E. M.; Jain, B.; Kent, S.; Kirk, D.; MacCrann, N.; Melchior, P.; Plazas, A. A.; Refregier, A.; Rowe, B.; Rykoff, E. S.; Samuroff, S.; Sánchez, C.; Suchyta, E.; Troxel, M. A.; Vikram, V.; Abbott, T.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Clampitt, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Fausti Neto, A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; March, M.; Martini, P.; Miquel, R.; Mohr, J. J.; Neilsen, E.; Nord, B.; Ogando, R.; Reil, K.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Walker, A. R.; Wechsler, R. H.

    2016-08-01

    We present weak lensing shear catalogues for 139 square degrees of data taken during the Science Verification (SV) time for the new Dark Energy Camera (DECam) being used for the Dark Energy Survey (DES). We describe our object selection, point spread function estimation and shear measurement procedures using two independent shear pipelines, IM3SHAPE and NGMIX, which produce catalogues of 2.12 million and 3.44 million galaxies, respectively. We detail a set of null tests for the shear measurements and find that they pass the requirements for systematic errors at the level necessary for weak lensing science applications using the SV data. We also discuss some of the planned algorithmic improvements that will be necessary to produce sufficiently accurate shear catalogues for the full 5-yr DES, which is expected to cover 5000 square degrees.

  7. In-office microwave disinfection of soft contact lenses

    SciTech Connect

    Harris, M.G.; Rechberger, J.; Grant, T.; Holden, B.A. )

    1990-02-01

    We evaluated the effectiveness of an in-office microwave disinfection procedure which allowed for the disinfection of up to 40 soft contact lenses at one time. Ciba AOSept cases filled with sterile unpreserved saline were contaminated with one of six FDA test challenge microorganisms at a concentration of approximately 10(3) colony forming units per milliliter (CFU/ml). Twenty cases were placed on the rotating plate of a standard 2450 MHz 650 W microwave oven in a 10-cm diameter circle. The cases were exposed to high intensity microwave irradiation for periods of 0 to 15 min. None of the 6 microorganisms evaluated survived 2 min or longer of microwave exposure. Our findings indicated that microwave irradiation can be a convenient, rapid, and effective method of disinfecting a number of soft contact lenses at one time and thus adaptable as an in-office soft contact lens disinfection procedure.

  8. The DES Science Verification Weak Lensing Shear Catalogs

    DOE PAGESBeta

    Jarvis, M.

    2016-05-01

    We present weak lensing shear catalogs for 139 square degrees of data taken during the Science Verification (SV) time for the new Dark Energy Camera (DECam) being used for the Dark Energy Survey (DES). We describe our object selection, point spread function estimation and shear measurement procedures using two independent shear pipelines, IM3SHAPE and NGMIX, which produce catalogs of 2.12 million and 3.44 million galaxies respectively. We also detail a set of null tests for the shear measurements and find that they pass the requirements for systematic errors at the level necessary for weak lensing science applications using the SVmore » data. Furthermore, we discuss some of the planned algorithmic improvements that will be necessary to produce sufficiently accurate shear catalogs for the full 5-year DES, which is expected to cover 5000 square degrees.« less

  9. The DES Science Verification Weak Lensing Shear Catalogues

    NASA Astrophysics Data System (ADS)

    Jarvis, M.; Sheldon, E.; Zuntz, J.; Kacprzak, T.; Bridle, S. L.; Amara, A.; Armstrong, R.; Becker, M. R.; Bernstein, G. M.; Bonnett, C.; Chang, C.; Das, R.; Dietrich, J. P.; Drlica-Wagner, A.; Eifler, T. F.; Gangkofner, C.; Gruen, D.; Hirsch, M.; Huff, E. M.; Jain, B.; Kent, S.; Kirk, D.; MacCrann, N.; Melchior, P.; Plazas, A. A.; Refregier, A.; Rowe, B.; Rykoff, E. S.; Samuroff, S.; Sánchez, C.; Suchyta, E.; Troxel, M. A.; Vikram, V.; Abbott, T.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Castander, F. J.; Clampitt, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Neto, A. Fausti; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; March, M.; Martini, P.; Miquel, R.; Mohr, J. J.; Neilsen, E.; Nord, B.; Ogando, R.; Reil, K.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Walker, A. R.; Wechsler, R. H.

    2016-05-01

    We present weak lensing shear catalogues for 139 square degrees of data taken during the Science Verification (SV) time for the new Dark Energy Camera (DECam) being used for the Dark Energy Survey (DES). We describe our object selection, point spread function estimation and shear measurement procedures using two independent shear pipelines, IM3SHAPE and NGMIX, which produce catalogues of 2.12 million and 3.44 million galaxies respectively. We detail a set of null tests for the shear measurements and find that they pass the requirements for systematic errors at the level necessary for weak lensing science applications using the SV data. We also discuss some of the planned algorithmic improvements that will be necessary to produce sufficiently accurate shear catalogues for the full 5-year DES, which is expected to cover 5000 square degrees.

  10. Gravitational lensing size scales for quasars

    NASA Astrophysics Data System (ADS)

    Chartas, G.; Rhea, C.; Kochanek, C.; Dai, X.; Morgan, C.; Blackburne, J.; Chen, B.; Mosquera, A.; MacLeod, C.

    2016-05-01

    We review results from our monitoring observations of several lensed quasars performed in the optical, UV, and X-ray bands. Modeling of the multi-wavelength light curves provides constraints on the extent of the optical, UV, and X-ray emission regions. One of the important results of our analysis is that the optical sizes as inferred from the microlensing analysis are significantly larger than those predicted by the theoretical-thin-disk estimate. In a few cases we also constrain the slope of the size-wavelength relation. Our size constraints of the soft and hard X-ray emission regions of quasars indicate that in some objects of our sample the hard X-ray emission region is more compact than the soft and in others the soft emission region is smaller. This difference may be the result of the relative strengths of the disk-reflected (harder and extended) versus corona-direct (softer and compact) components in the quasars of our sample. Finally, we present the analysis of several strong microlensing events where we detect an evolution of the relativistic Fe line profile as the magnification caustic traverses the accretion disk. These caustic crossings are used to provide constraints on the innermost stable circular orbit (ISCO) radius and the accretion disk inclination angle of the black hole in quasar RX J1131-1231.

  11. Standardized methods for assessing the imaging quality of intraocular lenses

    NASA Astrophysics Data System (ADS)

    Norrby, N. E. Sverker

    1995-11-01

    The relative merits of three standardized methods for assessing the imaging quality of intraocular lenses are discussed based on theoretical modulation-transfer-function calculations. The standards are ANSI Z80.7 1984 from the American National Standards Institute, now superseded by ANSI Z80.7 1994, and the proposed ISO 11979-2 from the International Organization for Standardization. They entail different test 60% resolution efficiency in air, 70% resolutionefficiency in aqueous humor, and 0.43 modulation at 100 line pairs/mm in a model eye. The ISO working group found that the latter corresponds to 60% resolution efficiency in air in a ring test among eight laboratories on a sample of 39 poly(methyl) methacrylate lenses and four silicone lenses spanning the power (in aqueous humor) range of 10-30 D. In both ANSI Z80.7 1994 and ISO 11979-2, a 60% resolution efficiency in air remains an optional approval limit. It is concluded that the ISO configuration is preferred, because it puts the intraocular lens into the context of the optics of the eye. Note that the ISO standard is tentative and is currently being voted on.

  12. Standardized methods for assessing the imaging quality of intraocular lenses.

    PubMed

    Norrby, N E

    1995-11-01

    The relative merits of three standardized methods for assessing the imaging quality of intraocular lenses are discussed based on theoretical modulation-transfer-function calculations. The standards are ANSI Z80.7 1984 from the American National Standards Institute, now superseded by ANSI Z80.7 1994, and the proposed ISO 11979-2 from the International Organization for Standardization. They entail different test configurations and approval limits, respectively: 60% resolution efficiency in air, 70% resolution efficiency in aqueous humor, and 0.43 modulation at 100 line pairs/mm in a model eye. The ISO working group found that the latter corresponds to 60% resolution efficiency in air in a ring test among eight laboratories on a sample of 39 poly(methyl) methacrylate lenses and four silicone lenses spanning the power (in aqueous humor) range of 10-30 D. In both ANSI Z80.7 1994 and ISO 11979-2, a 60% resolution efficiency in air remains an optional approval limit. It is concluded that the ISO configuration is preferred, because it puts the intraocular lens into the context of the optics of the eye. Note that the ISO standard is tentative and is currently being voted on. PMID:21060604

  13. Evidence for gravitational lensing of the cosmic microwave background polarization from cross-correlation with the cosmic infrared background.

    PubMed

    Ade, P A R; Akiba, Y; Anthony, A E; Arnold, K; Atlas, M; Barron, D; Boettger, D; Borrill, J; Borys, C; Chapman, S; Chinone, Y; Dobbs, M; Elleflot, T; Errard, J; Fabbian, G; Feng, C; Flanigan, D; Gilbert, A; Grainger, W; Halverson, N W; Hasegawa, M; Hattori, K; Hazumi, M; Holzapfel, W L; Hori, Y; Howard, J; Hyland, P; Inoue, Y; Jaehnig, G C; Jaffe, A; Keating, B; Kermish, Z; Keskitalo, R; Kisner, T; Le Jeune, M; Lee, A T; Leitch, E M; Linder, E; Lungu, M; Matsuda, F; Matsumura, T; Meng, X; Miller, N J; Morii, H; Moyerman, S; Myers, M J; Navaroli, M; Nishino, H; Paar, H; Peloton, J; Poletti, D; Quealy, E; Rebeiz, G; Reichardt, C L; Richards, P L; Ross, C; Rotermund, K; Schanning, I; Schenck, D E; Sherwin, B D; Shimizu, A; Shimmin, C; Shimon, M; Siritanasak, P; Smecher, G; Spieler, H; Stebor, N; Steinbach, B; Stompor, R; Suzuki, A; Takakura, S; Tikhomirov, A; Tomaru, T; Wilson, B; Yadav, A; Zahn, O

    2014-04-01

    We reconstruct the gravitational lensing convergence signal from cosmic microwave background (CMB) polarization data taken by the Polarbear experiment and cross-correlate it with cosmic infrared background maps from the Herschel satellite. From the cross spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0σ and indication of the presence of a lensing B-mode signal at a significance of 2.3σ. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics. PMID:24745402

  14. Evidence for Gravitational Lensing of the Cosmic Microwave Background Polarization from Cross-Correlation with the Cosmic Infrared Background

    NASA Astrophysics Data System (ADS)

    Ade, P. A. R.; Akiba, Y.; Anthony, A. E.; Arnold, K.; Atlas, M.; Barron, D.; Boettger, D.; Borrill, J.; Borys, C.; Chapman, S.; Chinone, Y.; Dobbs, M.; Elleflot, T.; Errard, J.; Fabbian, G.; Feng, C.; Flanigan, D.; Gilbert, A.; Grainger, W.; Halverson, N. W.; Hasegawa, M.; Hattori, K.; Hazumi, M.; Holzapfel, W. L.; Hori, Y.; Howard, J.; Hyland, P.; Inoue, Y.; Jaehnig, G. C.; Jaffe, A.; Keating, B.; Kermish, Z.; Keskitalo, R.; Kisner, T.; Le Jeune, M.; Lee, A. T.; Leitch, E. M.; Linder, E.; Lungu, M.; Matsuda, F.; Matsumura, T.; Meng, X.; Miller, N. J.; Morii, H.; Moyerman, S.; Myers, M. J.; Navaroli, M.; Nishino, H.; Paar, H.; Peloton, J.; Poletti, D.; Quealy, E.; Rebeiz, G.; Reichardt, C. L.; Richards, P. L.; Ross, C.; Rotermund, K.; Schanning, I.; Schenck, D. E.; Sherwin, B. D.; Shimizu, A.; Shimmin, C.; Shimon, M.; Siritanasak, P.; Smecher, G.; Spieler, H.; Stebor, N.; Steinbach, B.; Stompor, R.; Suzuki, A.; Takakura, S.; Tikhomirov, A.; Tomaru, T.; Wilson, B.; Yadav, A.; Zahn, O.; Polarbear Collaboration

    2014-04-01

    We reconstruct the gravitational lensing convergence signal from cosmic microwave background (CMB) polarization data taken by the Polarbear experiment and cross-correlate it with cosmic infrared background maps from the Herschel satellite. From the cross spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0σ and indication of the presence of a lensing B-mode signal at a significance of 2.3σ. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics.

  15. Edge shape and comfort of rigid lenses.

    PubMed

    La Hood, D

    1988-08-01

    One of the main factors determining the comfort of a rigid contact lens is the shape of the edge. The comfort of four different contact lens edge shapes was assessed with four unadapted subjects in a randomized masked trial. Lenses with well rounded anterior edge profiles were found to be significantly more comfortable than lenses with square anterior edges. There was no significant difference in subjective comfort between a rounded and square posterior edge profile. The results suggest that the interaction of the edge with the eyelid is more important in determining comfort than edge effects on the cornea, when lenses are fitted according to a corneal alignment philosophy. PMID:3177585

  16. Wettability and silicone hydrogel lenses: a review.

    PubMed

    Keir, Nancy; Jones, Lyndon

    2013-01-01

    One of the major breakthroughs in the development of silicone hydrogel contact lenses has related to the ability of manufacturers to overcome the surface hydrophobicity that occurred with silicone elastomer lenses. However, the wettability of silicone hydrogel lenses continues to be of interest as a potential link between in vivo lens performance and contact lens-related comfort. This article will review some of the knowledge we have gained in the area of contact lens wettability over the past decade and will discuss some of the challenges related to its measurement. PMID:23274760

  17. Twin axial vortices generated by Fibonacci lenses.

    PubMed

    Calatayud, Arnau; Ferrando, Vicente; Remón, Laura; Furlan, Walter D; Monsoriu, Juan A

    2013-04-22

    Optical vortex beams, generated by Diffractive Optical Elements (DOEs), are capable of creating optical traps and other multi-functional micromanipulators for very specific tasks in the microscopic scale. Using the Fibonacci sequence, we have discovered a new family of DOEs that inherently behave as bifocal vortex lenses, and where the ratio of the two focal distances approaches the golden mean. The disctintive optical properties of these Fibonacci vortex lenses are experimentally demonstrated. We believe that the versatility and potential scalability of these lenses may allow for new applications in micro and nanophotonics. PMID:23609732

  18. Tevatron Electron Lenses: Design and Operation

    SciTech Connect

    Shiltsev, Vladimir; Bishofberger, Kip; Kamerdzhiev, Vsevolod; Kozub, Sergei; Kufer, Matthew; Kuznetsov, Gennady; Martinez, Alexander; Olson, Marvin; Pfeffer, Howard; Saewert, Greg; Scarpine, Vic; /Fermilab /SLAC /Fermilab /Serpukhov, IHEP /Novosibirsk, IYF /Serpukhov, IHEP /Fermilab

    2008-08-01

    The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

  19. Adjustable fluidic lenses for ophthalmic corrections

    PubMed Central

    Marks, Randall; Mathine, David L.; Peyman, Gholam; Schwiegerling, Jim; Peyghambarian, Nasser

    2010-01-01

    We report on two fluidic lenses that have been developed for ophthalmic applications. The lenses use a circular aperture to demonstrate optical powers between −20 and +20 D and a rectangular aperture to demonstrate astigmatism with values ranging from 0 to 8 D. Measurements of image quality were made with the fluidic lens using a model eye. Both lenses were variable and controllable by adjusting the fluid volume of the lens. To the best of our knowledge this is the first demonstration of a continuously variable lens for control of astigmatism. PMID:19373359

  20. Using cross correlations to calibrate lensing source redshift distributions: Improving cosmological constraints from upcoming weak lensing surveys

    SciTech Connect

    De Putter, Roland; Doré, Olivier; Das, Sudeep

    2014-01-10

    Cross correlations between the galaxy number density in a lensing source sample and that in an overlapping spectroscopic sample can in principle be used to calibrate the lensing source redshift distribution. In this paper, we study in detail to what extent this cross-correlation method can mitigate the loss of cosmological information in upcoming weak lensing surveys (combined with a cosmic microwave background prior) due to lack of knowledge of the source distribution. We consider a scenario where photometric redshifts are available and find that, unless the photometric redshift distribution p(z {sub ph}|z) is calibrated very accurately a priori (bias and scatter known to ∼0.002 for, e.g., EUCLID), the additional constraint on p(z {sub ph}|z) from the cross-correlation technique to a large extent restores the cosmological information originally lost due to the uncertainty in dn/dz(z). Considering only the gain in photo-z accuracy and not the additional cosmological information, enhancements of the dark energy figure of merit of up to a factor of four (40) can be achieved for a SuMIRe-like (EUCLID-like) combination of lensing and redshift surveys, where SuMIRe stands for Subaru Measurement of Images and Redshifts). However, the success of the method is strongly sensitive to our knowledge of the galaxy bias evolution in the source sample and we find that a percent level bias prior is needed to optimize the gains from the cross-correlation method (i.e., to approach the cosmology constraints attainable if the bias was known exactly).

  1. Probing Dark Energy with Weak Lensing with LSST

    NASA Astrophysics Data System (ADS)

    Dell'Antonio, Ian P.; Wittman, D.; Jain, B.; Bosch, J.; Clowe, D.; Jarvis, M.; Jee, M.; Tyson, J.; Zhan, H.; LSST Weak Lensing Science Collaboration

    2011-01-01

    LSST will measure the shape, magnitude, and colors of more than 3x109 galaxies over 20,000 square degrees. These data will be used in several complementary ways to measure the properties of dark energy. Reconstruction of the shear power spectrum on linear and non-linear scales l /< 2000, and of the cross-correlation of shear measured in different photometric redshift bins, provides a constraint on the evolution of dark energy that is complementary to the purely geometric measures provided by Supernovae and BAO. Combining weak lensing and BAO measurements breaks degeneracies and results in tighter constraints on dark energy than each method can provide individually. Cross-correlation of the shear and galaxy number density signal within redshift shells minimizes the sensitivity to photo-z errors. Measurements of the shear bispectrum constrain dark energy and allow an independent test of theories of gravity. In addition to the galaxy shape correlations, LSST will detect 50,000 shear peaks with significance greater than 4σ, and 10,000 securely detected clusters of galaxies with line-of-sight velocity dispersions greater than 700 km/s. These allow independent constraints on the dark energy signature in the growth of structure. Tomographic study of the shear of background galaxies as a function of redshift allows the a geometric test of dark energy to be extracted from the weak lensing data. Finally, lensing signatures beyond the shear (magnification and flexion) will be accessible with LSST with unprecedented statistical power. The ability of LSST to extract the dark energy signal will depend on the accuracy with which the stellar PSF can be determined, and on the unbiased reconstruction of object shapes from long sequences of exposures in which the objects are detected at low significance. We discuss the prospects for cosmological constraints from weak lensing studies with LSST.

  2. Electrically-tunable liquid crystal lenses and applications

    NASA Astrophysics Data System (ADS)

    Lin, Yi-Hsin; Chen, Hung-Shan; Chen, Ming-Syuan

    2013-03-01

    In this paper, the electrically-tunable liquid crystal (LC) lenses and the applications are reviewed. We introduce the basic mechanism of LC phase modulation first. LC lenses are categorized based on different operating principles: 1) Gradient Index (GRIN) LC lenses with a homogeneous cell gap, 2) non-GRIN LC lenses with an inhomogeneous cell gap, 3) diffractive LC lenses, and 4) LC lenses controlled by polarizations. To remove the polarization independency, we also summarize polarization independent LC phase modulations. Many promising applications based on LC lenses are also summarized, such as imaging system, pico projectors, optical zoom systems, ophthalmic applications, and solar systems.

  3. Controlled Induction of Spherical Aberration with Custom Soft Contact Lenses

    PubMed Central

    Parker, Katrina E.; Marsack, Jason D.; Elswick, James D.; Brunstetter, Tyson J.; Applegate, Raymond A.

    2009-01-01

    Background This study investigated the non-invasive induction of spherical aberration (SA) levels consistent with complication-free wavefront-guided (WFG) refractive surgery using custom WFG soft contact lenses and quantified the resulting impact on visual performance. Methods Twelve healthy individuals of typical military age (mean of 26.08, SD ± 1.92 years) meeting the inclusion criteria of emmetropia (< ±0.50DS and < ±0.50DC) as measured by subjective refraction served as subjects. Five plano lenses were manufactured to induce a range of SA typical of those encountered after refractive surgery. The measured SA values over a 6mm artificial pupil in these five lenses were −0.224μm, 0.074μm, 0.214μm, 0.495μm and 0.621μm, respectively. For each subject, the level of total ocular aberration through 10 Zernike radial orders over a 6mm pupil was measured with a custom Shack-Hartmann wavefront sensor while wearing each lens. Visual performance was evaluated using high contrast visual acuity (HCVA) measured through a 6mm artificial pupil. Results Custom WFG soft contact lenses can be manufactured to include the range of SA that occurs with complication-free refractive surgery (−0.20μm to +0.60μm) and produces a change in SA within a similar range when worn on the eye. High contrast visual performance with these lenses varied depending on the amount of SA in each lens. Visual performance worsened with greater amounts of positive or negative SA and a quadratic fit to the data peaked at +0.209μm. Conclusions Defined levels of SA can be manufactured and induced (non-invasively) with WFG soft contact lenses and their effect on logMAR high contrast visual performance can be measured. Results show that subjects’ best logMAR HCVA occurs with the presence of positive residual SA. When designing the actual test lens, the targeted change in aberration for each subject will likely be better achieved by first measuring the aberrations of a template lens on the eye

  4. Liquid cell with plasmon lenses for surface enhanced raman spectroscopy.

    SciTech Connect

    Vlasko-Vlasov, V.; Joshi-Imre, A.; Bahns, J. T.; Chen, L.; Ocola, L.; Welp, U.

    2010-05-17

    High-fidelity surface enhanced Raman spectra (SERS) of Rhodamine 6G and 2-mercaptopyrimidine liquid solutions are measured using a microfluidic delivery system constructed on a flat silver substrate. Microscopic plasmon lenses patterned in the silver film focus surface plasmons into a subwavelength spot which yields the light amplification required for SERS. The system provides an efficiency similar to traditional colloidal substrates, and allows multiple sample loading. We find that the main contribution to the spectra comes from the molecules directly attached to the silver surface, which gives strong evidence for the chemical enhancement of SERS.

  5. Verification test problems for the calculation of probability of loss of assured safety in temperature-dependent systems with multiple weak and strong links.

    SciTech Connect

    Johnson, Jay Dean; Oberkampf, William Louis; Helton, Jon Craig (Arizona State University, Tempe, AZ)

    2006-06-01

    Four verification test problems are presented for checking the conceptual development and computational implementation of calculations to determine the probability of loss of assured safety (PLOAS) in temperature-dependent systems with multiple weak links (WLs) and strong links (SLs). The problems are designed to test results obtained with the following definitions of loss of assured safety: (1) Failure of all SLs before failure of any WL, (2) Failure of any SL before failure of any WL, (3) Failure of all SLs before failure of all WLs, and (4) Failure of any SL before failure of all WLs. The test problems are based on assuming the same failure properties for all links, which results in problems that have the desirable properties of fully exercising the numerical integration procedures required in the evaluation of PLOAS and also possessing simple algebraic representations for PLOAS that can be used for verification of the analysis.

  6. Use of HPLC/UPLC-spectrophotometry for detection of formazan in in vitro Reconstructed human Tissue (RhT)-based test methods employing the MTT-reduction assay to expand their applicability to strongly coloured test chemicals.

    PubMed

    Alépée, N; Barroso, J; De Smedt, A; De Wever, B; Hibatallah, J; Klaric, M; Mewes, K R; Millet, M; Pfannenbecker, U; Tailhardat, M; Templier, M; McNamee, P

    2015-06-01

    A number of in vitro test methods using Reconstructed human Tissues (RhT) are regulatory accepted for evaluation of skin corrosion/irritation. In such methods, test chemical corrosion/irritation potential is determined by measuring tissue viability using the photometric MTT-reduction assay. A known limitation of this assay is possible interference of strongly coloured test chemicals with measurement of formazan by absorbance (OD). To address this, Cosmetics Europe evaluated use of HPLC/UPLC-spectrophotometry as an alternative formazan measurement system. Using the approach recommended by the FDA guidance for validation of bio-analytical methods, three independent laboratories established and qualified their HPLC/UPLC-spectrophotometry systems to reproducibly measure formazan from tissue extracts. Up to 26 chemicals were then tested in RhT test systems for eye/skin irritation and skin corrosion. Results support that: (1) HPLC/UPLC-spectrophotometry formazan measurement is highly reproducible; (2) formazan measurement by HPLC/UPLC-spectrophotometry and OD gave almost identical tissue viabilities for test chemicals not exhibiting colour interference nor direct MTT reduction; (3) independent of the test system used, HPLC/UPLC-spectrophotometry can measure formazan for strongly coloured test chemicals when this is not possible by absorbance only. It is therefore recommended that HPLC/UPLC-spectrophotometry to measure formazan be included in the procedures of in vitro RhT-based test methods, irrespective of the test system used and the toxicity endpoint evaluated to extend the applicability of these test methods to strongly coloured chemicals. PMID:25701760

  7. The impact of camera optical alignments on weak lensing measures for the Dark Energy Survey

    SciTech Connect

    Antonik, M. L.; Bacon, D. J.; Bridle, S.; Doel, P.; Brooks, D.; Worswick, S.; Bernstein, G.; Bernstein, R.; DePoy, D.; Flaugher, B.; Frieman, J. A.; Gladders, M.; Gutierrez, G.; Jain, B.; Jarvis, M.; Kent, S. M.; Lahav, O.; Parker, S. -. J.; Roodman, A.; Walker, A. R.

    2013-04-10

    Telescope point spread function (PSF) quality is critical for realizing the potential of cosmic weak lensing observations to constrain dark energy and test general relativity. In this paper, we use quantitative weak gravitational lensing measures to inform the precision of lens optical alignment, with specific reference to the Dark Energy Survey (DES). We compute optics spot diagrams and calculate the shear and flexion of the PSF as a function of position on the focal plane. For perfect optical alignment, we verify the high quality of the DES optical design, finding a maximum PSF contribution to the weak lensing shear of 0.04 near the edge of the focal plane. However, this can be increased by a factor of approximately 3 if the lenses are only just aligned within their maximum specified tolerances. We calculate the E- and B-mode shear and flexion variance as a function of the decentre or tilt of each lens in turn. We find tilt accuracy to be a few times more important than decentre, depending on the lens considered. Finally, we consider the compound effect of decentre and tilt of multiple lenses simultaneously, by sampling from a plausible range of values of each parameter. We find that the compound effect can be around twice as detrimental as when considering any one lens alone. Furthermore, this combined effect changes the conclusions about which lens is most important to align accurately. For DES, the tilt of the first two lenses is the most important.

  8. The effects of camera lenses and dental specialties on the perception of smile esthetics

    PubMed Central

    Sajjadi, Seyed Hadi; Khosravanifard, Behnam; Esmaeilpour, Mozhgan; Rakhshan, Vahid; Moazzami, Fatemeh

    2015-01-01

    Background and Aim: The purpose of this study was to investigate whether different camera lenses and dental specialties can affect the perception of smile esthetics. Methods: In the first phase of this study, 40 female smile photographs (taken from dental students) were evaluated by six orthodontists, three specialists in restorative dentistry, and three prosthodontists to select the most beautiful smiles. The 20 students with the best smile ranks were again photographed in standard conditions, but this time with two different lenses: Regular and then macro lenses. Each referee evaluated the beauty of the smiles on a visual analog scale. The referees were blinded of the type of lenses, and the images were all coded. The data were analyzed using two-way analysis of variance (ANOVA), Kruskal–Wallis and Mann–Whitney U-tests (alpha = 0.05, alpha = 0.0167). Results: The lenses led to similar scores of beauty perception (Mann–Whitney P = 0.8). There was no difference between subjective beauty perception of specialties (Kruskal–Wallis P = 0.6). Two-way ANOVA indicated no significant role for lenses (P = 0.1750), specialties (P = 0.7677), or their interaction (P = 0.7852). Conclusion: The photographs taken by a regular lens and then digitally magnified can be as appealing as close-up photographs taken by a macro lens. Experts in different specialties (orthodontics, prosthodontics, and restorative dentistry) showed similar subjective judgments of smile beauty. PMID:26952147

  9. Tear exchange and contact lenses: A review

    PubMed Central

    Muntz, Alex; Subbaraman, Lakshman N.; Sorbara, Luigina; Jones, Lyndon

    2015-01-01

    Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses. PMID:25575892

  10. Contact lenses and the work environment.

    PubMed

    Mäkitie, J

    1984-01-01

    Controversial opinions have been presented about the use of contact lenses in industrial environments. Work environments contain few obstacles to the use of contact lenses, but many occupations are associated with the risk of excessive difficulties, spoilation , irritation, or complications. From the radiant energy the shorter (280 nm) ultraviolet (UV) wavelengths and the longer (1300 nm) infra-red (IR) wavelengths are absorbed by contact lenses, the absorption increases their temperature and may cause corneal complications. Protective glasses, however, absorb more than 99.5% of the UV and IR energy and thus provide sufficient protection for contact lens wearers exposed to UV or IR radiation. The advantages and risks of contact lenses in industrial work are discussed. PMID:6328841

  11. Current indications for scleral contact lenses.

    PubMed

    Foss, A J; Trodd, T C; Dart, J K

    1994-04-01

    Scleral contact lenses have been largely superseded by corneal contact lenses, but they still retain a role as a treatment of choice for a small group of patients who have tried other types of contact lens wear without success and who are not good candidates for surgery. We performed a cross sectional survey of 44 patients attending clinics at Moorfields Eye Hospital who were successful long-term scleral contact lens wearers and reviewed their indications. Twenty-one patients had been fit to improve visual acuity, 20 for therapeutic indications, and three for cosmetic reasons. Scleral lenses were most useful were with patients with ocular surface disorders, such as Stevens-Johnson syndrome, and for visual rehabilitation of patients with grossly irregular corneal topography. All patients were benefiting from scleral contact lens wear, and none had serious complications as a result of the scleral lens wear. We conclude that all ophthalmic departments should have access to these lenses. PMID:8044976

  12. Nanofocusing Parabolic Refractive X-Ray Lenses

    SciTech Connect

    Schroer, C.G.; Kuhlmann, M.; Hunger, U.T.; Guenzler, T.F.; Kurapova, O.; Feste, S.; Lengeler, B.; Drakopoulos, M.; Somogyi, A.; Simionovici, A. S.; Snigirev, A.; Snigireva, I.

    2004-05-12

    Parabolic refractive x-ray lenses with short focal distance can generate intensive hard x-ray microbeams with lateral extensions in the 100nm range even at short distance from a synchrotron radiation source. We have fabricated planar parabolic lenses made of silicon that have a focal distance in the range of a few millimeters at hard x-ray energies. In a crossed geometry, two lenses were used to generate a microbeam with a lateral size of 330nm by 110nm at 25keV in a distance of 41.8m from the synchrotron radiation source. First microdiffraction and fluorescence microtomography experiments were carried out with these lenses. Using diamond as lens material, microbeams with lateral size down to 20nm and below are conceivable in the energy range from 10 to 100keV.

  13. A weak lensing mass reconstruction of the large-scale filament feeding the massive galaxy cluster MACS J0717.5+3745

    NASA Astrophysics Data System (ADS)

    Jauzac, Mathilde; Jullo, Eric; Kneib, Jean-Paul; Ebeling, Harald; Leauthaud, Alexie; Ma, Cheng-Jiun; Limousin, Marceau; Massey, Richard; Richard, Johan

    2012-11-01

    We report the first weak lensing detection of a large-scale filament funnelling matter on to the core of the massive galaxy cluster MACS J0717.5+3745. Our analysis is based on a mosaic of 18 multipassband images obtained with the Advanced Camera for Surveys aboard the Hubble Space Telescope, covering an area of ˜10 × 20 arcmin2. We use a weak lensing pipeline developed for the Cosmic Evolution Survey, modified for the analysis of galaxy clusters, to produce a weak lensing catalogue. A mass map is then computed by applying a weak gravitational lensing multiscale reconstruction technique designed to describe irregular mass distributions such as the one investigated here. We test the resulting mass map by comparing the mass distribution inferred for the cluster core with the one derived from strong lensing constraints and find excellent agreement. Our analysis detects the MACS J0717.5+3745 filament within the 3σ detection contour of the lensing mass reconstruction, and underlines the importance of filaments for theoretical and numerical models of the mass distribution in the cosmic web. We measure the filament's projected length as ˜4.5 h74-1 Mpc, and its mean density as (2.92 ± 0.66) × 108 h74 M⊙ kpc-2. Combined with the redshift distribution of galaxies obtained after an extensive spectroscopic follow-up in the area, we can rule out any projection effect resulting from the chance alignment on the sky of unrelated galaxy group-scale structures. Assuming plausible constraints concerning the structure's geometry based on its galaxy velocity field, we construct a three-dimensional (3D) model of the large-scale filament. Within this framework, we derive the 3D length of the filament to be 18 h74-1 Mpc. The filament's deprojected density in terms of the critical density of the Universe is measured as (206 ± 46) ρcrit, a value that lies at the very high end of the range predicted by numerical simulations. Finally, we study the distribution of stellar mass in the

  14. Tests of General Relativity in the Strong-gravity Regime Based on X-Ray Spectropolarimetric Observations of Black Holes in X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Krawczynski, Henric

    2012-08-01

    Although general relativity (GR) has been tested extensively in the weak-gravity regime, similar tests in the strong-gravity regime are still missing. In this paper, we explore the possibility to use X-ray spectropolarimetric observations of black holes in X-ray binaries to distinguish between the Kerr metric and the phenomenological metrics introduced by Johannsen & Psaltis (which are not vacuum solutions of Einstein's equation) and thus to test the no-hair theorem of GR. To this end, we have developed a numerical code that calculates the radial brightness profiles of accretion disks and parallel transports the wave vector and polarization vector of photons through the Kerr and non-GR spacetimes. We used the code to predict the observational appearance of GR and non-GR accreting black hole systems. We find that the predicted energy spectra and energy-dependent polarization degree and polarization direction do depend strongly on the underlying spacetime. However, for large regions of the parameter space, the GR and non-GR metrics lead to very similar observational signatures, making it difficult to observationally distinguish between the two types of models.

  15. TESTS OF GENERAL RELATIVITY IN THE STRONG-GRAVITY REGIME BASED ON X-RAY SPECTROPOLARIMETRIC OBSERVATIONS OF BLACK HOLES IN X-RAY BINARIES

    SciTech Connect

    Krawczynski, Henric

    2012-08-01

    Although general relativity (GR) has been tested extensively in the weak-gravity regime, similar tests in the strong-gravity regime are still missing. In this paper, we explore the possibility to use X-ray spectropolarimetric observations of black holes in X-ray binaries to distinguish between the Kerr metric and the phenomenological metrics introduced by Johannsen and Psaltis (which are not vacuum solutions of Einstein's equation) and thus to test the no-hair theorem of GR. To this end, we have developed a numerical code that calculates the radial brightness profiles of accretion disks and parallel transports the wave vector and polarization vector of photons through the Kerr and non-GR spacetimes. We used the code to predict the observational appearance of GR and non-GR accreting black hole systems. We find that the predicted energy spectra and energy-dependent polarization degree and polarization direction do depend strongly on the underlying spacetime. However, for large regions of the parameter space, the GR and non-GR metrics lead to very similar observational signatures, making it difficult to observationally distinguish between the two types of models.

  16. Measuring neutrino masses with weak lensing

    SciTech Connect

    Wong, Yvonne Y. Y.

    2006-11-17

    Weak gravitational lensing of distant galaxies by large scale structure (LSS) provides an unbiased way to map the matter distribution in the low redshift universe. This technique, based on the measurement of small distortions in the images of the source galaxies induced by the intervening LSS, is expected to become a key cosmological probe in the future. We discuss how future lensing surveys can probe the sum of the neutrino masses at the 0 05 eV level.

  17. Electron lenses for particle collimation in LHC

    SciTech Connect

    Shiltsev, v.; /Fermilab

    2007-12-01

    Electron Lenses built and installed in Tevatron have proven themselves as safe and very reliable instruments which can be effectively used in hadron collider operation for a number of applications, including compensation of beam-beam effects [1], DC beam removal from abort gaps [2], as a diagnostic tool. In this presentation we - following original proposal [3] - consider in more detail a possibility of using electron lenses with hollow electron beam for ion and proton collimation in LHC.

  18. The general theory of secondary weak gravitational lensing

    NASA Astrophysics Data System (ADS)

    Clarkson, Chris

    2015-09-01

    Weak gravitational lensing is normally assumed to have only two principle effects: a magnification of a source and a distortion of the sources shape in the form of a shear. However, further distortions are actually present owing to changes in the gravitational field across the scale of the ray bundle of light propagating to us, resulting in the familiar arcs in lensed images. This is normally called the flexion, and is approximated by Taylor expanding the shear and magnification across the image plane. However, the physical origin of this effect arises from higher-order corrections in the geodesic deviation equation governing the gravitational force between neighbouring geodesics— so involves derivatives of the Riemann tensor. We show that integrating the second-order geodesic deviation equation results in a `Hessian map' for gravitational lensing, which is a higher-order addition to the Jacobi map. We derive the general form of the Hessian map in an arbitrary spacetime paying particular attention to the separate effects of local Ricci versus non-local Weyl curvature. We then specialise to the case of a perturbed FLRW model, and give the general form of the Hessian for the first time. This has a host of new contributions which could in principle be used as tests for modified gravity.

  19. Metrology of achromatic diffractive features on chalcogenide lenses

    NASA Astrophysics Data System (ADS)

    Scordato, M.; Nelson, J.; Schwertz, K.; Mckenna, P.; Bagwell, J.

    2015-10-01

    Achromatic diffractive features on lenses are widely used in industry for color correction, however there is not a welldefined standard to quantify the performance of the lenses. One metric used to qualify a lens is the sag deviation from the nominal lens profile. Imperfections in the manufacturing of the diffractive feature may cause scattering and performance loss. This is not reflected in sag deviation measurements, therefore performance measurements are required. There are different quantitative approaches to measuring the performance of an achromatic diffractive lens. Diffraction efficiency, a measure of optical power throughput, is a common design metric used to define the percent drop from the modulation transfer function (MTF) metric. The line spread function (LSF) shows a layout of the intensity with linear distance and an ensquared energy specification can be implemented. The MTF is a common analysis tool for assemblies and can be applied to a single element. These functional tests will be performed and compared with diffractive lenses manufactured by different tool designs. This paper displays the results found with various instruments. Contact profilometry was used to inspect the profile of the diffractive elements, and a MTF bench was used to characterize lens performance. Included will be a discussion comparing the results of profile traces and beam profiles to expected diffraction efficiency values and the effects of manufacturing imperfections.

  20. Colored lenses suppress blue light-emitting diode light-induced damage in photoreceptor-derived cells

    NASA Astrophysics Data System (ADS)

    Hiromoto, Kaho; Kuse, Yoshiki; Tsuruma, Kazuhiro; Tadokoro, Nobuyuki; Kaneko, Nobuyuki; Shimazawa, Masamitsu; Hara, Hideaki

    2016-03-01

    Blue light-emitting diodes (LEDs) in liquid crystal displays emit high levels of blue light, exposure to which is harmful to the retina. Here, we investigated the protective effects of colored lenses in blue LED light-induced damage to 661W photoreceptor-derived cells. We used eight kinds of colored lenses and one lens that reflects blue light. Moreover, we evaluated the relationship between the protective effects of the lens and the transmittance of lens at 464 nm. Lenses of six colors, except for the SY, PN, and reflective coating lenses, strongly decreased the reduction in cell damage induced by blue LED light exposure. The deep yellow lens showed the most protective effect from all the lenses, but the reflective coating lens and pink lens did not show any effects on photoreceptor-derived cell damage. Moreover, these results were correlated with the lens transmittance of blue LED light (464 nm). These results suggest that lenses of various colors, especially deep yellow lenses, may protect retinal photoreceptor cells from blue LED light in proportion to the transmittance for the wavelength of blue LED and the suppression of reactive oxygen species production and cell damage.

  1. The SuperCLASS Weak Lensing Deep Field Survey

    NASA Astrophysics Data System (ADS)

    Harrison, Ian; Superclass Collaboration

    2014-04-01

    SuperCLASS is a survey of 1.75 square degrees of the Northern sky using the e-MERLIN telescope array at a frequency of 1.4GHz, aiming to reach an image noise RMS level of 4 micro-Jy/beam. The primary goal is to use the expected source density of ~1 per square arcminute (giving a total of ~10,000), ~150 milli-arcsecond resolution and presence in the survey region of 5 massive Abell clusters to measure a significant weak lensing effect in the radio band for only the second time, proving the potential of radio weak lensing as a powerful tool for mapping dark matter and constraining cosmological models. In doing this we will also learn a significant amount about the source population (star forming galaxies and radio AGN) themselves and their polarisation properties. SuperCLASS will not only require development of a pipeline for making the highly accurate determination of shapes of a large number of sources for performing standard weak lensing measurements, but will also form a test bed for new methods, such as the use of polarisation information to mitigate the biasing effect of intrinsic alignments between galaxies, which will be a key systematic for future weak lensing surveys. Whilst the challenges of the necessary shape measurement in image plane optical data are relatively well-explored, there is little experience in meeting those involved in the use of data from radio interferometers. The knowledge gained about efficient and accurate techniques for large scale radio astronomy from SuperCLASS will be invaluable in the build up to the next generation of experiments.

  2. Ophthalmic glucose monitoring using disposable contact lenses.

    PubMed

    Geddes, Chris

    2004-01-01

    We have developed a range of disposable and colorless tear glucose sensing contact lenses, using off-the-shelf lenses embedded with new water soluble, highly fluorescent and glucose sensitive boronic acid containing fluorophores. The new lenses are readily able to track tear glucose levels and therefore blood glucose levels, which are ideally suited for potential use by diabetics. The fluorescence responses from the lenses can be monitored using simple excitation and emission detection devices. The novelty of our approach is two fold. Firstly, the notion of sensing extremely low glucose concentrations in tears, which track blood levels, by our contact lens approach, and secondly, the unique compatibility of our new glucose signaling probes with the internal mildly acidic contact lens environment. The new lenses are therefore ideal for the noninvasive and continuous monitoring of tear glucose, with a 15 minute response time, and a measured shelf life in excess of 3 months. In this invited article, we show that fluorescence based signaling using plastic disposable lenses, which have already been industrially optimized with regard to vision correction and oxygen / analyte permeability etc, may a notable alternative to invasive and random finger pricking, the most widely used glucose monitoring technology by diabetics. PMID:17271473

  3. Perspective projection camera model for zoom lenses

    NASA Astrophysics Data System (ADS)

    Willson, Reg G.; Shafer, Steven A.

    1994-03-01

    To effectively use automated zoom lenses for machine vision we need camera models that are valid over continuous ranges of lens settings. While camera calibration has been the subject of much research in machine vision and photogrammetry, for the most part the resulting models and calibration techniques have been for cameras with fixed parameter lenses where the lens' imaging process is static. For cameras with automated lenses the image formation process is a dynamic function of the lens control parameters. The complex nature of the relationships between the control parameters and the imaging process plus the need to calibrate them over a continuum of lens settings makes both the modeling and the calibration of cameras with automated zoom lenses fundamentally more difficult than that of cameras with fixed parameter lenses. In this paper we illustrate some of the problems involved with the modeling and calibration of cameras with variable parameter lenses. We then show how an iterative, empirical approach to modeling and calibration can produce a dynamic camera model of perspective projection that holds calibration across a continuous range of zoom.

  4. Two Lensed Lyman-α Emitting Galaxies at z~ 5

    NASA Astrophysics Data System (ADS)

    Bayliss, Matthew B.; Wuyts, Eva; Sharon, Keren; Gladders, Michael D.; Hennawi, Joseph F.; Koester, Benjamin P.; Dahle, Håkon

    2010-09-01

    We present observations of two strongly lensed z ~ 5 Lyman-α emitting galaxies that were discovered in the Sloan Giant Arcs Survey (SGAS). We identify the two sources as SGAS J091541+382655 at z = 5.200 and SGAS J134331+415455 at z = 4.994. We measure their AB magnitudes at (i, z) = (23.34 ± 0.09, 23.29 ± 0.13) mag and (i, z) = (23.78 ± 0.18, 24.24+0.18 -0.16) mag and the rest-frame equivalent widths of the Lyman-α emission at 25.3 ± 4.1 Å and 135.6 ± 20.3 Å for SGAS J091541+382655 and SGAS J134331+415455, respectively. Each source is strongly lensed by a massive galaxy cluster in the foreground, and the magnifications due to gravitational lensing are recovered from strong lens modeling of the foreground lensing potentials. We use the magnification to calculate the intrinsic, unlensed Lyman-α and UV continuum luminosities for both sources, as well as the implied star formation rates. We find SGAS J091541+382655 and SGAS J134341+415455 to be galaxies with (L Ly-α, L UV) <= (0.6 L* Ly-α, 2 L*UV) and (L Ly-α, L UV) = (0.5 L* Ly-α, 0.9 L*UV), respectively. Comparison of the spectral energy distributions of both sources against stellar population models produces estimates of the mass in young stars in each galaxy; we report an upper limit of M stars <= 7.9+3.7 -2.5 × 107 M sun h -1 0.7 for SGAS J091531+382655 and a range of viable masses for SGAS J134331+415455 of 2 × 108 M sun h -1 0.7< M stars < 6 × 109 M sun h -1 0.7. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovaci

  5. Polycapillary lenses for Soft-X-ray transmission: Model, comparison with experiments and potential application for tomographic measurements in tokamaks

    NASA Astrophysics Data System (ADS)

    Mazon, D.; Abadie, Q.; Dorchies, F.; Lecherbourg, L.; Mollard, A.; Malard, P.; Dabagov, S.

    2015-07-01

    In tokamaks, plasma emits as a volumetric Soft-X-ray (SXR) source. Emitted X-rays can give very useful information about plasma stability, shape and impurity content. Measuring the Soft X-ray (SXR) radiation ([0.1-20 keV]) of magnetic fusion plasmas is a standard way of accessing valuable information on particle transport and MagnetoHydroDynamic. Generally, like at Tore Supra in France, the analysis is performed with a 2D tomographic system composed of several cameras equipped with detectors like Silicon Barrier Diodes spread in periphery of the tokamak. Unfortunately, the strong constraints imposed by the environment of a tokamak reactor (high neutron fluxes, gamma and hard X-ray emission, high magnetic field and high radiofrequency powers) do not authorize to install in a close vicinity of the machine such detectors. We have thus investigated the possibility of using polycapillary lenses to transport the SXR information to several meters from the plasma, not necessarily in a straight line. The idea is to protect the SXR detector from the entire environment by a proper shielding. Different polycapillary lenses could be used for that purpose and have been tested in collaboration with CELIA (CEA-CNRS) of Bordeaux. Transmission of the order of 20% where observed for the low energetic part of the spectrum (down to 3 keV) while still 10% were observed for the remaining part (from 3 to 10 keV). In parallel a model of polycapillary transmission has been developed and validated against experiment. Results are presented confirming the great potential of polycapillary lenses for SXR transmission in tokamak plasma. Studies of the influence of geometrical parameters like diameter and curvature of the channels, on the photons transmission is also presented.

  6. Discovery of a new component in the gravitationally lensed quasar 0957 + 561

    NASA Technical Reports Server (NTRS)

    Jones, C.; Stern, C.; Falco, E.; Forman, W.; David, L.; Shapiro, I.; Fabian, A. C.

    1993-01-01

    X-ray observations of the gravitationally lensed quasar 0957 + 561 with the Einstein Observatory High Resolution Imager indicate the presence of a new component in the system. The significantly greater X-ray intensity of image A compared with image B and the extended X-ray emission can be interpreted as the gravitational lensing of a quasi-circular X-ray emitting region into a partial Einstein ring. It is suggested that the observed X-ray emission is produced by a strong cooling flow which could arise were 0957 + 561 embedded in a group of cluster galaxies.

  7. WITNESSING THE DIFFERENTIAL EVOLUTION OF DISK GALAXIES IN LUMINOSITY AND SIZE VIA GRAVITATIONAL LENSING

    SciTech Connect

    Bandara, Kaushala; Crampton, David; Peng, Chien; Simard, Luc

    2013-11-01

    We take advantage of the magnification in size and flux of a galaxy provided by gravitational lensing to analyze the properties of 62 strongly lensed galaxies from the Sloan Lens ACS (SLACS) Survey. The sample of lensed galaxies spans a redshift range of 0.20 ≤ z ≤ 1.20 with a median redshift of z = 0.61. We use the lens modeling code LENSFIT to derive the luminosities, sizes, and Sérsic indices of the lensed galaxies. The measured properties of the lensed galaxies show a primarily compact, {sup d}isk{sup -}like population with the peaks of the size and Sérsic index distributions corresponding to ∼1.50 kpc and n ∼ 1, respectively. Comparison of the SLACS galaxies to a non-lensing, broadband imaging survey shows that a lensing survey allows us to probe a galaxy population that reaches ∼2 mag fainter. Our analysis allows us to compare the (z) = 0.61 disk galaxy sample (n ≤ 2.5) to an unprecedented local galaxy sample of ∼670, 000 SDSS galaxies at z ∼ 0.1; this analysis indicates that the evolution of the luminosity-size relation since z ∼ 1 may not be fully explained by a pure-size or pure-luminosity evolution but may instead require a combination of both. Our observations are also in agreement with recent numerical simulations of disk galaxies that show evidence of a mass-dependent evolution since z ∼ 1, where high-mass disk galaxies (M{sub *} > 10{sup 9} M{sub ☉}) evolve more in size and low-mass disk galaxies (M{sub *} ≤ 10{sup 9} M{sub ☉}) evolve more in luminosity.

  8. Validation of geometric models for fisheye lenses

    NASA Astrophysics Data System (ADS)

    Schneider, D.; Schwalbe, E.; Maas, H.-G.

    The paper focuses on the photogrammetric investigation of geometric models for different types of optical fisheye constructions (equidistant, equisolid-angle, sterographic and orthographic projection). These models were implemented and thoroughly tested in a spatial resection and a self-calibrating bundle adjustment. For this purpose, fisheye images were taken with a Nikkor 8 mm fisheye lens on a Kodak DSC 14n Pro digital camera in a hemispherical calibration room. Both, the spatial resection and the bundle adjustment resulted in a standard deviation of unit weight of 1/10 pixel with a suitable set of simultaneous calibration parameters introduced into the camera model. The camera-lens combination was treated with all of the four basic models mentioned above. Using the same set of additional lens distortion parameters, the differences between the models can largely be compensated, delivering almost the same precision parameters. The relative object space precision obtained from the bundle adjustment was ca. 1:10 000 of the object dimensions. This value can be considered as a very satisfying result, as fisheye images generally have a lower geometric resolution as a consequence of their large field of view and also have a inferior imaging quality in comparison to most central perspective lenses.

  9. Surface Modification of Intraocular Lenses

    PubMed Central

    Huang, Qi; Cheng, George Pak-Man; Chiu, Kin; Wang, Gui-Qin

    2016-01-01

    Objective: This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs). Data Sources: All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect. Study Selection: The articles on the surface modification of IOLs were included, but those on design modification and surface coating were excluded. Results: Technology of surface modification included plasma, ion beam, layer-by-layer self-assembly, ultraviolet radiation, and ozone. The main molecules introduced into IOLs surface were poly (ethylene glycol), polyhedral oligomeric silsesquioxane, 2-methacryloyloxyethyl phosphorylcholine, TiO2, heparin, F-heparin, titanium, titanium nitride, vinyl pyrrolidone, and inhibitors of cytokines. The surface modification either resulted in a more hydrophobic lens, a more hydrophilic lens, or a lens with a hydrophilic anterior and hydrophobic posterior surface. Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments. Conclusion: The surface modification is an efficient, convenient, economic and promising method to improve the biocompatibility of IOLs. PMID:26830993

  10. Lense-Thirring precession around neutron stars with known spin

    NASA Astrophysics Data System (ADS)

    Van Doesburgh, Marieke; van der Klis, Michiel

    2016-07-01

    Quasi periodic oscillations (QPOs) between 300 and 1200 Hz in the X-ray emission from low mass X-ray binaries have been linked to Keplerian orbital motion at the inner edge of accretion disks. Lense-Thirring precession is precession of the line of nodes of inclined orbits with respect to the equatorial plane of a rotating object due to the general relativistic effect of frame dragging. The Lense-Thirring model of Stella and Vietri (1998) explains QPOs observed in neutron star low mass X-ray binaries at frequencies of a few tens of Hz by the nodal precession of the orbits at the inner disk edge at a precession frequency, ν_{LT} , identical to the Lense-Thirring precession of a test particle orbit. A quadratic relation between ν_{LT} and the Keplerian orbital frequency, and a linear dependence on spin frequency are predicted. In early work (van Straaten et al., 2003) this quadratic relation was confirmed to remarkable precision in three objects of uncertain spin. Since the initial work, many neutron star spin frequencies have been measured in X-ray sources that show QPOs at both low and high frequency. Using archival data from the Rossi X-ray Timing Explorer, we compare the Lense-Thirring prediction to the properties of quasi periodic oscillations measured in a sample of 14 low mass X-ray binaries of which the neutron star spin frequencies can be inferred from their bursting behaviour. We find that in the range predicted for the precession frequency, we can distinguish two different oscillations that often occur simultaneously. In previous works, these two oscillations have often been confused. For both frequencies, we find correlations with inferred Keplerian frequency characterized by power laws with indices that differ significantly from the prediction of 2.0 and therefore inconsistent with the Lense-Thirring model. Also, the specific moment of inertia of the neutron star required by the observed frequencies exceeds values predicted for realistic equations of

  11. Thermal lensing in Nd:YVO4 laser with in-band pumping at 914 nm

    NASA Astrophysics Data System (ADS)

    Waritanant, Tanant; Major, Arkady

    2016-05-01

    Thermal lensing in an Nd:YVO4 laser system operating at 1064 nm with in-band pumping at 914 nm was characterized. The focal length of the thermal lens in the crystal was calculated using ABCD matrix formalism from the experimental data of the output beam diameter measurements made at different output power levels. The determined focal lengths of thermal lens were as strong as 4.4 diopters at 3.5 W of output power. The experimental results agree well with the finite element analysis of the developed laser system. A numerical comparison of the thermal lensing effect with 914-, 888-, 880-nm pumping, and with a standard 808-nm pumping was also made, demonstrating effective reduction of thermal lensing up to 2.1 times.

  12. Candidate Gravitationally Lensed Dusty Star-forming Galaxies in the Herschel Wide Area Surveys

    NASA Astrophysics Data System (ADS)

    Nayyeri, H.; Keele, M.; Cooray, A.; Riechers, D. A.; Ivison, R. J.; Harris, A. I.; Frayer, D. T.; Baker, A. J.; Chapman, S. C.; Eales, S.; Farrah, D.; Fu, H.; Marchetti, L.; Marques-Chaves, R.; Martinez-Navajas, P. I.; Oliver, S. J.; Omont, A.; Perez-Fournon, I.; Scott, D.; Vaccari, M.; Vieira, J.; Viero, M.; Wang, L.; Wardlow, J.

    2016-05-01

    We present a list of candidate gravitationally lensed dusty star-forming galaxies (DSFGs) from the HerMES Large Mode Survey and the Herschel Stripe 82 Survey. Together, these partially overlapping surveys cover 372 deg2 on the sky. After removing local spiral galaxies and known radio-loud blazars, our candidate list of lensed DSFGs is composed of 77 sources with 500 μm flux densities (S 500) greater than 100 mJy. Such sources are dusty starburst galaxies similar to the first bright sub-millimeter galaxies (SMGs) discovered with SCUBA. We expect a large fraction of this list to be strongly lensed, with a small fraction made up of bright SMG–SMG mergers that appear as hyper-luminous infrared galaxies ({L}{IR}\\gt {10}13 {L}ȯ ). Thirteen of the 77 candidates have spectroscopic redshifts from CO spectroscopy with ground-based interferometers, putting them at z\\gt 1 and well above the redshift of the foreground lensing galaxies. The surface density of our sample is 0.21 ± 0.03 deg‑2. We present follow-up imaging of a few of the candidates to confirm their lensing nature. The sample presented here is an ideal tool for higher-resolution imaging and spectroscopic observations to understand the detailed properties of starburst phenomena in distant galaxies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  13. SDSS J133401.39+331534.3: A NEW SUBARCSECOND GRAVITATIONALLY LENSED QUASAR

    SciTech Connect

    Rusu, Cristian E.; Iye, Masanori; Oguri, Masamune; Inada, Naohisa; Kayo, Issha; Hayano, Yutaka; Oya, Shin; Hattori, Masayuki; Saito, Yoshihiko; Ito, Meguru; Minowa, Yosuke; Pyo, Tae-Soo; Terada, Hiroshi; Takami, Hideki; Watanabe, Makoto

    2011-09-01

    The quasar SDSS J133401.39+331534.3 at z = 2.426 is found to be a two-image gravitationally lensed quasar with an image separation of 0.''833. The object is first identified as a lensed quasar candidate in the Sloan Digital Sky Survey Quasar Lens Search, and then confirmed as a lensed system from follow-up observations at the Subaru and University of Hawaii 2.2 m telescopes. We estimate the redshift of the lensing galaxy to be 0.557 based on absorption lines in the quasar spectra as well as the color of the galaxy. In particular, we observe the system with the Subaru Telescope AO188 adaptive optics with a laser guide star, in order to derive accurate astrometry, which well demonstrates the usefulness of the laser guide star adaptive optics imaging for studying strong lens systems. Our mass modeling with improved astrometry implies that a nearby bright galaxy {approx}4'' apart from the lensing galaxy is likely to affect the lens potential.

  14. Weak Lensing Analysis of IDCS J1426.5+3508: A Massive Galaxy Cluster at z=1.75

    NASA Astrophysics Data System (ADS)

    Mo, Wenli

    2015-08-01

    We present a weak lensing study of the galaxy cluster IDCS J1426.5+3508 which, at z=1.75, is the highest redshift strong lensing cluster known and the most distant cluster for which a weak lensing analysis has been undertaken. Using F160W, F814W, and F606W observations with the Hubble Space Telescope, we detect a tangential shear signal out to a radius of ~1 Mpc. Fitting the shear to a Navarro-Frenk-White mass profile, we derive a mass that agrees with previous masses calculated from the Sunyaev-Zel'dovich (SZ) effect, X-ray, and strong lensing observations. The combination of weak lensing and SZ measurements are consistent with the scaling relation observed at low redshift, indicative of minimal evolution in this relation. The cluster concentration is not well-constrained by the weak lensing data alone, but we derive a concentration using the SZ mass measurements as a prior. It has previously been noted that an exceptionally high concentration might afford a means to explain the unexpected existence of a giant arc in this cluster. Our data argue that the concentration is not unusually large, indicating that an alternate solution is required.

  15. Molding aspheric lenses for low-cost production versus diamond turned lenses

    NASA Astrophysics Data System (ADS)

    Cogburn, Gabriel; Mertus, Louis; Symmons, Alan

    2010-04-01

    As lens design using aspheric diffractive lenses has become more popular in designing faster, low F/# infrared (IR) optical systems; the increased quantities manufactured of these glass lenses is following suit. Historically, Single Point Diamond Turning (SPDT) has been the method of choice in producing high quality glass aspheric and diffractive lenses, but with the volume of lenses produced and technological advances in Precision Molded Optics (PMO), it is now becoming highly cost efficient to use molding as a means of producing these glass optic lenses. This paper will discuss lens shapes, tolerances, present and future optic lens sizes that are being done using PMO as well as present an experiment conducted comparing the surface quality of a chalcogenide lens manufactured with SPDT and PMO.

  16. First measurement of the cross-correlation of CMB lensing and galaxy lensing

    NASA Astrophysics Data System (ADS)

    Hand, Nick; Leauthaud, Alexie; Das, Sudeep; Sherwin, Blake D.; Addison, Graeme E.; Bond, J. Richard; Calabrese, Erminia; Charbonnier, Aldée; Devlin, Mark J.; Dunkley, Joanna; Erben, Thomas; Hajian, Amir; Halpern, Mark; Harnois-Déraps, Joachim; Heymans, Catherine; Hildebrandt, Hendrik; Hincks, Adam D.; Kneib, Jean-Paul; Kosowsky, Arthur; Makler, Martin; Miller, Lance; Moodley, Kavilan; Moraes, Bruno; Niemack, Michael D.; Page, Lyman A.; Partridge, Bruce; Sehgal, Neelima; Shan, Huanyuan; Sievers, Jonathan L.; Spergel, David N.; Staggs, Suzanne T.; Switzer, Eric R.; Taylor, James E.; Van Waerbeke, Ludovic; Welker, Charlotte; Wollack, Edward J.

    2015-03-01

    We measure the cross-correlation of cosmic microwave background (CMB) lensing convergence maps derived from Atacama Cosmology Telescope data with galaxy lensing convergence maps as measured by the Canada-France-Hawaii Telescope Stripe 82 Survey. The CMB-galaxy lensing cross power spectrum is measured for the first time with a significance of 4.2 σ , which corresponds to a 12% constraint on the amplitude of density fluctuations at redshifts ˜0.9 . With upcoming improved lensing data, this novel type of measurement will become a powerful cosmological probe, providing a precise measurement of the mass distribution at intermediate redshifts and serving as a calibrator for systematic biases in weak lensing measurements.

  17. LENSING MAGNIFICATION: A NOVEL METHOD TO WEIGH HIGH-REDSHIFT CLUSTERS AND ITS APPLICATION TO SpARCS

    SciTech Connect

    Hildebrandt, H.; Van Waerbeke, L.; Muzzin, A.; Erben, T.; Hoekstra, H.; Kuijken, K.; Surace, J.; Wilson, G.; Yee, H. K. C.

    2011-06-01

    We introduce a novel method to measure the masses of galaxy clusters at high redshift selected from optical and IR Spitzer data via the red-sequence technique. Lyman-break galaxies are used as a well-understood, high-redshift background sample allowing mass measurements of lenses at unprecedented high redshifts using weak lensing magnification. By stacking a significant number of clusters at different redshifts with average masses of {approx}(1-3) x 10{sup 14} M{sub sun}, as estimated from their richness, we can calibrate the normalization of the mass-richness relation. With the current data set (area: 6 deg{sup 2}) we detect a magnification signal at the >3{sigma} level. There is good agreement between the masses estimated from the richness of the clusters and the average masses estimated from magnification, albeit with large uncertainties. We perform tests that suggest the absence of strong systematic effects and support the robustness of the measurement. This method-when applied to larger data sets in the future-will yield an accurate calibration of the mass-observable relations at z {approx}> 1 which will represent an invaluable input for cosmological studies using the galaxy cluster mass function and astrophysical studies of cluster formation. Furthermore, this method will probably be the least expensive way to measure masses of large numbers of z > 1 clusters detected in future IR-imaging surveys.

  18. HerMES: A Deficit in the Surface Brightness of the Cosmic Infrared Background due to Galaxy Cluster Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Zemcov, M.; Blain, A.; Cooray, A.; Béthermin, M.; Bock, J.; Clements, D. L.; Conley, A.; Conversi, L.; Dowell, C. D.; Farrah, D.; Glenn, J.; Griffin, M.; Halpern, M.; Jullo, E.; Kneib, J.-P.; Marsden, G.; Nguyen, H. T.; Oliver, S. J.; Richard, J.; Roseboom, I. G.; Schulz, B.; Scott, Douglas; Shupe, D. L.; Smith, A. J.; Valtchanov, I.; Viero, M.; Wang, L.; Wardlow, J.

    2013-06-01

    We have observed four massive galaxy clusters with the SPIRE instrument on the Herschel Space Observatory and measure a deficit of surface brightness within their central region after removing detected sources. We simulate the effects of instrumental sensitivity and resolution, the source population, and the lensing effect of the clusters to estimate the shape and amplitude of the deficit. The amplitude of the central deficit is a strong function of the surface density and flux distribution of the background sources. We find that for the current best fitting faint end number counts, and excellent lensing models, the most likely amplitude of the central deficit is the full intensity of the cosmic infrared background (CIB). Our measurement leads to a lower limit to the integrated total intensity of the CIB of I_{250 \\, \\mu {m}} \\gt 0.69_{-0.03}^{+0.03} ({stat.}) _{-0.06}^{+0.11} ({sys.}) MJy sr-1, with more CIB possible from both low-redshift sources and from sources within the target clusters. It should be possible to observe this effect in existing high angular resolution data at other wavelengths where the CIB is bright, which would allow tests of models of the faint source component of the CIB. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  19. HerMES: A DEFICIT IN THE SURFACE BRIGHTNESS OF THE COSMIC INFRARED BACKGROUND DUE TO GALAXY CLUSTER GRAVITATIONAL LENSING

    SciTech Connect

    Zemcov, M.; Cooray, A.; Bock, J.; Dowell, C. D.; Nguyen, H. T.; Blain, A.; Bethermin, M.; Conley, A.; Glenn, J.; Conversi, L.; Farrah, D.; Oliver, S. J.; Roseboom, I. G.; Griffin, M.; Halpern, M.; Marsden, G.; Jullo, E.; Kneib, J.-P.; Richard, J.; and others

    2013-06-01

    We have observed four massive galaxy clusters with the SPIRE instrument on the Herschel Space Observatory and measure a deficit of surface brightness within their central region after removing detected sources. We simulate the effects of instrumental sensitivity and resolution, the source population, and the lensing effect of the clusters to estimate the shape and amplitude of the deficit. The amplitude of the central deficit is a strong function of the surface density and flux distribution of the background sources. We find that for the current best fitting faint end number counts, and excellent lensing models, the most likely amplitude of the central deficit is the full intensity of the cosmic infrared background (CIB). Our measurement leads to a lower limit to the integrated total intensity of the CIB of I{sub 250{mu}m}>0.69{sub -0.03}{sup +0.03}(stat.){sub -0.06}{sup +0.11}(sys.) MJy sr{sup -1}, with more CIB possible from both low-redshift sources and from sources within the target clusters. It should be possible to observe this effect in existing high angular resolution data at other wavelengths where the CIB is bright, which would allow tests of models of the faint source component of the CIB.

  20. The Herschel Lensing Survey (HLS): HST Frontier Field Coverage

    NASA Astrophysics Data System (ADS)

    Egami, Eiichi

    2015-08-01

    The Herschel Lensing Survey (HLS; PI: Egami) is a large Far-IR/Submm imaging survey of massive galaxy clusters using the Herschel Space Observatory. Its main goal is to detect and study IR/Submm galaxies that are below the nominal confusion limit of Herschel by taking advantage of the strong gravitational lensing power of massive galaxy clusters. HLS has obtained deep PACS (100/160 um) and SPIRE (250/350/500 um) images for 54 cluster fields (HLS-deep) as well as shallower but nearly confusion-limited SPIRE-only images for 527 cluster fields (HLS-snapshot) with a total observing time of ~420 hours. Extensive multi-wavelength follow-up studies are currently on-going with a variety of observing facilities including ALMA.Here, I will focus on the analysis of the deep Herschel PACS/SPIRE images obtained for the 6 HST Frontier Fields (5 observed by HLS-deep; 1 observed by the Herschel GT programs). The Herschel/SPIRE maps are wide enough to cover the Frontier-Field parallel pointings, and we have detected a total of ~180 sources, some of which are strongly lensed. I will present the sample and discuss the properties of these Herschel-detected dusty star-forming galaxies (DSFGs) identified in the Frontier Fields. Although the majority of these Herschel sources are at moderate redshift (z<3), a small number of extremely high-redshift (z>6) candidates can be identified as "Herschel dropouts" when combined with longer-wavelength data. We have also identified ~40 sources as likely cluster members, which will allow us to study the properties of DSFGs in the dense cluster environment.A great legacy of our HLS project will be the extensive multi-wavelength database that incorporates most of the currently available data/information for the fields of the Frontier-Field, CLASH, and other HLS clusters (e.g., HST/Spitzer/Herschel images, spectroscopic/photometric redshifts, lensing models, best-fit SED models etc.). Provided with a user-friendly GUI and a flexible search engine, this