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We report a detection of the coherent distortion of faint galaxies arising from gravitational lensing by foreground structures. This ``cosmic shear'' is potentially the most direct measure of the mass power spectrum, as it is unaffected by…

Astrophysics · Physics 2011-05-05 David Bacon , Alexandre Refregier , Richard Ellis

We have investigated, using both a theoretical and an empirical approach, the frequency of low redshift galaxy-galaxy lensing systems in which the signature of weak lensing might be directly detectable. We find good agreement between these…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Catherine O. de Burgh-Day , Edward N. Taylor , Rachel L. Webster , Andrew M. Hopkins

We have measured the correlation between the lensing signal induced by (dark) matter and number counts of galaxies on scales ranging from 0.15-3.0 h_{50}^{-1} Mpc (which correspond to aperture radii of 1-15 arcminutes). This provides a…

Astrophysics · Physics 2009-11-06 Henk Hoekstra , Howard K. C. Yee , Michael D. Gladders

We take a broad look at the problem of identifying the magnetic solar causes of space weather. With the lackluster performance of extrapolations based upon magnetic field measurements in the photosphere, we identify a region in the near UV…

Scanning near-field field optical microscopy (SNOM) is a technique, which allows sub-wavelength optical imaging of photonic structures. While the electric field components of light can be routinely obtained, imaging of the magnetic…

High precision astrometry aims at source position determination to a very small fraction of the diffraction image size, in high SNR regime. One of the key limitations to such goal is the optical response variation of the telescope over a…

Instrumentation and Methods for Astrophysics · Physics 2021-04-08 Alberto Riva , Mario Gai , Alberto Vecchiato , Deborah Busonero , Mario G. Lattanzi , Federico Landini , Zhaoxiang Qi , Zhenghong Tang

Far-UV observations in and near the Hubble Deep Fields demonstrate that the Space Telescope Imaging Spectrograph (STIS) can potentially obtain unique and precise measurements of the diffuse far-ultraviolet background. Although STIS is not…

In this paper, we show by experiment that by covering a thin flat nonlinear lens on the sources, the sub-diffraction-limit observation can be achieved by measuring either the near-field distribution or the far-field radiation of the sources…

Magnetometry with nitrogen-vacancy (NV) centers has so far been measured via emission of light from NV centers or via absorption at the singlet transition at 1042 nm. Here, we demonstrate a phenomenon of broadband optical absorption by the…

Many scientific deliverables of the next generation low frequency radio telescopes require high dynamic range imaging. Next generation telescopes under construction indeed promise at least a ten-fold increase in the sensitivity compared…

Instrumentation and Methods for Astrophysics · Physics 2009-06-03 S. Bhatnagar

High spatial resolution spectro-polarimetric observation of a decaying spot was observed with the Diffraction Limited Spectro-Polarimeter. The spatial resolution achieved was close to the diffraction limit (0."18) of the Dunn Solar…

Astrophysics · Physics 2008-01-21 K. Sankarasubramanian , H. Hagenaar

Images of SN1006 have a number of important properties. For instance, the bright limbs coincide spatially in various bands, they have different brightness, and the contrast of brightness varies from radio to gamma-rays. The reasons of such…

High Energy Astrophysical Phenomena · Physics 2015-05-30 O. Petruk , T. Kuzyo , F. Bocchino

Detecting exoplanets and other faint sources of emitted and reflected light near a bright star requires deeply suppressing the starlight while efficiently transmitting the dim light from its surroundings. This suppression can be carried out…

Instrumentation and Methods for Astrophysics · Physics 2024-11-07 Eugene Serabyn , Michael Bottom

We present a tomographic cosmological weak lensing analysis of the HST COSMOS Survey. Applying our lensing-optimized data reduction, principal component interpolation for the ACS PSF, and improved modelling of charge-transfer inefficiency,…

Despite the continuing importance of ground-based parallax measurements, few active programs remain. Because new members of the solar neighborhood tend towards later spectral types, infrared parallax programs are particularly desirable.…

Instrumentation and Methods for Astrophysics · Physics 2014-11-20 Jennifer Lynn Bartlett , Chan Park , Srikrishna Kanneganti , Philip A. Ianna

Accurate weak-lensing analysis requires not only accurate measurement of galaxy shapes but also precise and unbiased measurement of galaxy redshifts. The photometric redshift technique appears as the only possibility to determine the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 S. Jouvel , J-P. Kneib , G. Bernstein , O. Ilbert , P. Jelinsky , B. Milliard , A. Ealet , C. Schimd , T. Dahlen , S. Arnouts

The analysis of strong lensing images usually involves an external convergence and shear, which are meant to model the effect of perturbations along the line of sight, on top of the main lens. Such a description of line-of-sight…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-04 Théo Duboscq , Natalie B. Hogg , Pierre Fleury , Julien Larena

Cosmological simulations predict that galaxies are embedded into triaxial dark matter haloes, which appear approximately elliptical in projection. Weak gravitational lensing allows us to constrain these halo shapes and thereby test the…

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