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High precision cosmology with weak gravitational lensing requires a precise measure of the Point Spread Function across the imaging data where the accuracy to which high spatial frequency variation can be modelled is limited by the stellar…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Catherine Heymans , Barnaby Rowe , Henk Hoekstra , Lance Miller , Thomas Erben , Thomas Kitching , Ludovic Van Waerbeke

The ionosphere is the main driver of a series of systematic effects that limit our ability to explore the low frequency (<1 GHz) sky with radio interferometers. Its effects become increasingly important towards lower frequencies and are…

Instrumentation and Methods for Astrophysics · Physics 2018-08-08 F. de Gasperin , M. Mevius , D. A. Rafferty , H. T. Intema , R. A. Fallows

We develop a novel method to extract key cosmological information, which is primarily carried by the baryon acoustic oscillations and redshift space distortions, from spectroscopic galaxy surveys based on a joint principal component…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-03 Yuting Wang , Gong-Bo Zhao , John A. Peacock

Residual speckles in adaptive optics (AO) images represent a well-known limitation on the achievement of the contrast needed for faint source detection. Speckles in AO imagery can be the result of either residual atmospheric aberrations,…

The aim of this paper is to describe a novel non-parametric noise reduction technique from the point of view of Bayesian inference that may automatically improve the signal-to-noise ratio of one- and two-dimensional data, such as e.g.…

Instrumentation and Methods for Astrophysics · Physics 2023-07-07 Pablo M Sanchez-Alarcon , Yago Ascasibar Sequeiros

Fundamental information about the Universe is encoded in anisotropies of the Cosmic Microwave Background (CMB) radiation. To make full use of this information, an experiment must image the entire sky with the angular resolution,…

In ground-based high-contrast instruments, non-common path aberrations (NCPAs) limit detection performance, as they are unseen by the adaptive optics (AO) wavefront sensor but impact the astrophysical image, creating quasi-static speckles.…

Blind source separation (BSS) is a very popular technique to analyze multichannel data. In this context, the data are modeled as the linear combination of sources to be retrieved. For that purpose, standard BSS methods all rely on some…

Applications · Statistics 2015-06-23 Jerome Bobin , Jeremy Rapin , Anthony Larue , Jean-Luc Starck

An improved method is utilized to estimate the X-ray power spectral densities (PSD) and the variation time scales of three quasars in the Lockman Hole field. Five archival ROSAT PSPC data covering two year range are analyzed. To estimate…

Astrophysics · Physics 2015-06-24 Yu-ichiro Ezoe , Naoko Iyomoto , Kazuo Makishima , Gunter Hasinger

Contribution of resolved and unresolved extragalactic point sources to the low-frequency sky spectrum is a potentially non-negligible part of the astrophysical foregrounds for cosmic dawn 21-cm experiments. The clustering of such point…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-01 Shikhar Mittal , Girish Kulkarni , Dominic Anstey , Eloy de Lera Acedo

The Laser Interferometer Space Antenna (LISA) mission features a three-spacecraft long-arm constellation intended to detect gravitational wave sources in the low-frequency band up to 1 Hz via laser interferometry. The paper presents an…

Instrumentation and Detectors · Physics 2022-08-24 Niklas Houba , Simon Delchambre , Tobias Ziegler , Gerald Hechenblaikner , Walter Fichter

We suggest a new algorithm to remove systematic effects in a large set of lightcurves obtained by a photometric survey. The algorithm can remove systematic effects, like the ones associated with atmospheric extinction, detector efficiency,…

Astrophysics · Physics 2009-11-10 Omer Tamuz , Tsevi Mazeh , Shay Zucker

We present a new approach to constrain galaxy physical parameters from the combined interpretation of stellar and nebular emission in wide ranges of observations. This approach relies on the Bayesian analysis of any type of galaxy spectral…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Camilla Pacifici , Stephane Charlot , Jeremy Blaizot , Jarle Brinchmann

A limiting systematic effect in 21-cm interferometric experiments is the chromaticity due to the coupling between the sky and the instrument. This coupling is sourced by the instrument primary beam; therefore it is important to know the…

Instrumentation and Methods for Astrophysics · Physics 2022-06-22 Ainulnabilah Nasirudin , David Prelogovic , Steven G. Murray , Andrei Mesinger , Gianni Bernardi

Long-exposure spectro-polarimetry in the near-infrared is a preferred method to measure the magnetic field and other physical properties of solar prominences. In the past, it has been very difficult to observe prominences in this way with…

Instrumentation and Methods for Astrophysics · Physics 2015-08-11 G. E. Taylor , D. Schmidt , J. Marino , T. R. Rimmele , R. T. J. McAteer

In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging…

Astrophysics · Physics 2009-11-13 C. Marois , D. Lafreniere , B. Macintosh , R. Doyon

We investigate the limitations of statistical absorption measurements with the SDSS optical spectroscopic surveys. We show that changes in the data reduction strategy throughout different data releases have led to a better accuracy at long…

Instrumentation and Methods for Astrophysics · Physics 2018-04-05 Ting-Wen Lan , Brice Ménard , Dalya Baron , Sean Johnson , Dovi Poznanski , J. Xavier Prochaska , John O'Meara

Over the past 10 years Bayesian methods have rapidly grown more popular as several computationally intensive statistical algorithms have become feasible with increased computer power. In this paper, we begin with a general description of…

Astrophysics · Physics 2016-02-19 David A. van Dyk , Alanna Connors , Vinay L. Kashyap , Aneta Siemiginowska

Hyperspectral optical imaging provides rich spectral information for estimating continuous environmental and material parameters; however, its high dimensionality and strong feature correlation pose significant challenges for machine…

Optics · Physics 2025-12-18 Parisa Parand , Mahmoud Samadpour

A critical analysis and comparison of different methods for obtaining point spread function (PSF) photometry are carried out. Deep ACS observations of NGC3370 were reduced using four distinct approaches. These reductions explore a number of…

Astrophysics of Galaxies · Physics 2023-03-08 In Sung Jang