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We propose to use a simple observable, the fractional area of "hot spots" in weak gravitational lensing mass maps which are detected with high significance, to determine background cosmological parameters. Because these high-convergence…

Astrophysics · Physics 2011-02-11 Sheng Wang , Zoltán Haiman , Morgan May

We present a Monte Carlo simulation for the scattering of light in the case of an isotropic light source. The scattering phase functions are studied particularly in detail to understand how they can affect the multiple light scattering in…

Optics · Physics 2013-10-15 J. Colombi , K. Louedec

We present a Monte Carlo simulation for the scattering of light in the case of an isotropic light source. The scattering phase functions are studied particularly in detail to understand how they can affect the multiple light scattering in…

Instrumentation and Methods for Astrophysics · Physics 2014-02-18 J. Colombi , K. Louedec

We present a technique for estimating the mass in the outskirts of galaxy clusters where the usual assumption of dynamical equilibrium is not valid. The method assumes that clusters form through hierarchical clustering and requires only…

Astrophysics · Physics 2009-10-31 Antonaldo Diaferio

Cluster analysis has become one of the most exercised research areas over the past few decades in computer science. As a consequence, numerous clustering algorithms have already been developed to find appropriate partitions of a set of…

Human-Computer Interaction · Computer Science 2016-10-26 Abhisek Dash , Sujoy Chatterjee , Tripti Prasad , Malay Bhattacharyya

Clusters of galaxies are important laboratories for understanding both galaxy evolution and constraining cosmological quantities. Any analysis of clusters, however, is best done when one can reliably determine which galaxies are members of…

Astrophysics · Physics 2009-10-31 R. J. Brunner , L. M. Lubin

The simple 3-D radiative transfer model in the atmosphere of the Earth is built for numerical comparison of direct solar radiation and limb scattering background at the definite layer during the deep twilight period at the middle and upper…

Atmospheric and Oceanic Physics · Physics 2025-09-05 Oleg S. Ugolnikov

The direction angle of twilight sky background polarization in the celestial sphere points far from solar vertical is found to depend on the ratio of single and multiple scattering contributions. The polarization direction behavior during…

Atmospheric and Oceanic Physics · Physics 2015-03-06 Oleg S. Ugolnikov , Igor A. Maslov

We present a powerful method to extract per-point semantic class labels from aerialphotogrammetry data. Labeling this kind of data is important for tasks such as environmental modelling, object classification and scene understanding. Unlike…

Computer Vision and Pattern Recognition · Computer Science 2017-05-24 Carlos Becker , Nicolai Häni , Elena Rosinskaya , Emmanuel d'Angelo , Christoph Strecha

The optical properties of nanoparticles can be substantially affected by their assembly in compact aggregates. This is a common situation notably for nanoparticles synthesised and self-assembled into rigid clusters in colloidal form, where…

Optics · Physics 2022-04-27 Atefeh Fazel-Najafabadi , Baptiste Auguié

A new method is presented for determining the Point Spread Function (PSF) of images that lack bright and isolated stars. It is based on the same principles as the MCS (Magain, Courbin, Sohy, 1998) image deconvolution algorithm. It uses the…

Astrophysics · Physics 2009-11-11 P. Magain , F. Courbin , M. Gillon , S. Sohy , G. Letawe , V. Chantry , Y. Letawe

We investigate the potential and accuracy of clustering-based redshift estimation using the method proposed by M\'enard et al. (2013). This technique enables the inference of redshift distributions from measurements of the spatial…

Astrophysics of Galaxies · Physics 2015-06-22 Mubdi Rahman , Brice Ménard , Ryan Scranton , Samuel J. Schmidt , Christopher B. Morrison

We review the well-known matched filter method for the detection of point sources in astronomical images. This is shown to be optimal (that is, to saturate the Cramer--Rao bound) under stated conditions that are very strong: an isolated…

Instrumentation and Methods for Astrophysics · Physics 2021-01-01 Dustin Lang , David W. Hogg

This paper proposes a novel point-cloud-based place recognition system that adopts a deep learning approach for feature extraction. By using a convolutional neural network pre-trained on color images to extract features from a range image…

Computer Vision and Pattern Recognition · Computer Science 2018-10-24 Ting Sun , Ming Liu , Haoyang Ye , Dit-Yan Yeung

Clustering algorithms are one of the main analytical methods to detect patterns in unlabeled data. Existing clustering methods typically treat samples in a dataset as points in a metric space and compute distances to group together similar…

Machine Learning · Computer Science 2021-10-12 Tarek Naous , Srinjay Sarkar , Abubakar Abid , James Zou

The accurate determination of atom numbers is an ubiquitous problem in the field of ultracold atoms. For modest atom numbers, absolute calibration techniques are available, however, for large numbers and high densities, the available…

In this paper, the problem of de-noising of an image contaminated with additive white Gaussian noise (AWGN) is studied. This subject has been continued to be an open problem in signal processing for more than 50 years. In the present paper,…

Computer Vision and Pattern Recognition · Computer Science 2013-10-29 Mohsen Joneidi , Mostafa Sadeghi

Measurements of clustering in large-scale imaging surveys that make use of photometric redshifts depend on the uncertainties in the redshift determination. We have used light-cone simulations to show how the deprojection method successfully…

One of the main goals of modern observational cosmology is to map the large scale structure of the Universe. A potentially powerful approach for doing this would be to exploit three-dimensional spectral maps, i.e. the specific intensity of…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-18 Roland de Putter , Gilbert P. Holder , Tzu-Ching Chang , Olivier Dore

The atmospheric scattering of light has a significant influence on results of optical observations of air showers. It causes attenuation of direct light from the shower, but also contributes a delayed signal to the observed light. The…

Instrumentation and Methods for Astrophysics · Physics 2013-09-10 Jan Pekala , Henryk Wilczynski