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X-ray diffraction gratings play an essential role in high-resolution spectroscopy of astrophysical phenomena. We present some scientific highlights from the X-ray grating spectrometers (XGS) on board of the Chandra and XMM/Newton missions,…

Instrumentation and Methods for Astrophysics · Physics 2024-09-05 Ralf K. Heilmann , David P. Huenemoerder , Jake A. McCoy , Randall L. McEntaffer

By measuring, modeling and interpreting cosmological datasets, one can place strong constraints on models of the Universe. Central to this effort are summary statistics such as power spectra and bispectra, which condense the…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-15 Oliver H. E. Philcox , Thomas Flöss

Deviations from general relativity in order to explain cosmic acceleration generically have both time and scale dependent signatures in cosmological data. We extend our previous work by investigating model independent gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-23 Scott F. Daniel , Eric V. Linder

High-contrast long-slit spectrographs can be used to characterize exoplanets. High-contrast long-slit spectroscopic data are however corrupted by stellar leakages which largely dominate other signals and make the process of extracting the…

Instrumentation and Methods for Astrophysics · Physics 2023-10-11 Samuel Thé , Éric Thiébaut , Loïc Denis , Thibault Wanner , Rémi Thiébaut , Maud Langlois , Ferréol Soulez

We present a two-component Machine Learning (ML) based approach for classifying astronomical images by data-quality via an examination of sources detected in the images and image pixel values from representative sources within those images.…

Instrumentation and Methods for Astrophysics · Physics 2020-04-01 Hossen Teimoorinia , J. J. Kavelaars , Stephen Gwyn , Daniel Durand , Kennedy Rolston , Alexander Ouellette

Cosmic-ray particles with ultra-high energies (above $10^{18}$ eV) are studied through the properties of extensive air showers which they initiate in the atmosphere. The Pierre Auger Observatory detects these showers with unprecedented…

Instrumentation and Methods for Astrophysics · Physics 2019-08-13 J. Vicha , J. Chudoba

We describe a new approach for the determination of cosmological parameters using gravitational lensing systems with multiple arcs, exploiting the fact that a given cluster can produce multiple arcs from sources over a broad range in…

Astrophysics · Physics 2009-10-30 Robert Link , Michael J. Pierce

Spectral variability in hyperspectral images can result from factors including environmental, illumination, atmospheric and temporal changes. Its occurrence may lead to the propagation of significant estimation errors in the unmixing…

Computer Vision and Pattern Recognition · Computer Science 2020-01-23 Ricardo Augusto Borsoi , Tales Imbiriba , José Carlos Moreira Bermudez

Spectral signatures are crucial in the era of large X-ray surveys. Automatic machine learning methods have proven useful in this respect, but so far they have not been applied to large spectral datasets, such as the Chandra Source Catalog…

Instrumentation and Methods for Astrophysics · Physics 2026-05-19 Nicolò Oreste Pinciroli Vago , Juan Rafael Martínez-Galarza , Roberta Amato

The design of new x-ray phase contrast imaging setups often relies on Monte Carlo simulations for prospective parameter studies. Monte Carlo simulations are known to be accurate but time consuming, leading to long simulation times,…

Medical Physics · Physics 2022-10-19 Jonathan Sanctorum , Jan Sijbers , Jan De Beenhouwer

The redshift-space bispectrum (three point statistics) of galaxies depends on the expansion rate, the growth rate, and geometry of the Universe, and hence can be used to measure key cosmological parameters. In a homogeneous Universe the…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-25 Praful Gagrani , Lado Samushia

Astronomy has a long history of acquiring, systematizing, and interpreting large quantities of data. Starting from the earliest sky atlases through the first major photographic sky surveys of the 20th century, this tradition is continuing…

Astrophysics · Physics 2007-05-23 Robert J. Brunner , S. George Djorgovski , Thomas A. Prince , Alex S. Szalay

Today's astronomical projects need computational systems capable to store and analyze large amounts of scientific data, to effectively share data with other research Institutes and to easily implement information services to present data…

Astrophysics · Physics 2007-05-23 G. Calderone , L. Nicastro

In cosmic-ray physics, large field of view experiments are triggered by a number of signals laying on different angular scales: point-like and extended gamma-ray sources, diffuse emissions, as well as large and intermediate scale cosmic-ray…

High Energy Astrophysical Phenomena · Physics 2011-12-02 Roberto Iuppa

Astronomy produces extremely large data sets from ground-based telescopes, space missions, and simulation. The volume and complexity of these rich data sets require new approaches and advanced tools to understand the information contained…

Instrumentation and Methods for Astrophysics · Physics 2014-02-25 Demitri Muna , Eric Huff

Recent technological advances have led to a flood of new data on cosmology rich in information about the formation and evolution of the universe, e.g., the data collected in Sloan Digital Sky Survey (SDSS) for more than 200 million objects.…

Cosmology and Nongalactic Astrophysics · Physics 2009-02-25 Sabyasachi Mukhopadhyay , Sisir Roy , Sourabh Bhattacharya

High-volume feature-rich data sets are becoming the bread-and-butter of 21st century astronomy but present significant challenges to scientific discovery. In particular, identifying scientifically significant relationships between sets of…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Matthew J. Graham , S. G. Djorgovski , Ashish A. Mahabal , Ciro Donalek , Andrew J. Drake

We consider what is the best way to extract science from large surveys of the Milky Way galaxy. The diversity of data gathered in these surveys, together with our position within the Galaxy, imply that science must be extracted by fitting…

Astrophysics of Galaxies · Physics 2015-05-30 Paul J. McMillan , James Binney

By utilizing large-scale graph analytic tools implemented in the modern Big Data platform, Apache Spark, we investigate the topological structure of gravitational clustering in five different universes produced by cosmological $N$-body…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-04 Sungryong Hong , Donghui Jeong , Ho Seong Hwang , Juhan Kim , Sungwook E. Hong , Changbom Park , Arjun Dey , Milos Milosavljevic , Karl Gebhardt , Kyoung-Soo Lee

Gammapy is a Python package for high-level gamma-ray data analysis built on Numpy, Scipy and Astropy. It enables us to analyze gamma-ray data and to create sky images, spectra and lightcurves, from event lists and instrument response…

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