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Using higher-order statistics to capture cosmological information from weak lensing surveys often requires a transformation of observed shear to a measurement of the convergence signal. This inverse problem is complicated by noise and…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-25 Nisha Grewal , Joe Zuntz , Tilman Tröster

The rigorous coupled-wave approach (RCWA) and the differential evolution algorithm (DEA) were coupled in a practicable approach to maximize absorption in optical structures with three-dimensional morphology. As a model problem, optimal…

Applied Physics · Physics 2018-08-07 Benjamin J. Civiletti , Tom H. Anderson , Faiz Ahmad , Peter B. Monk , Akhlesh Lakhtakia

We present a novel procedure to estimate the Equation of State of the intergalactic medium in the quasi-linear regime of structure formation based on Ly$\alpha$ forest tomography and apply it to 21 high quality quasar spectra from the…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-07 Hendrik Müller , Christoph Behrens , David James Edward Marsh

We describe and experimentally validate an algorithm to reconstruct an unknown extended object from through-focus measured image intensities blurred by unknown aberrations. It is shown that the method can recover diffraction-limited image…

Optics · Physics 2015-10-29 Yifeng Shao , Niek Doelman , Silvania F. Pereira , H. Paul Urbach

We present here three recipes for getting better images with optical interferometers. Two of them, Low- Frequencies Filling and Brute-Force Monte Carlo were used in our participation to the Interferometry Beauty Contest this year and can be…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 Florentin Millour , Martin Vannier , Anthony Meilland

Numerical hydrodynamical simulations are used to predict the expected absorption properties of the Lyman-Alpha forest for a variety of Cold Dark Matter dominated cosmological scenarios: CHDM, OCDM, LCDM, SCDM, and tCDM. Synthetic spectra…

Astrophysics · Physics 2009-11-06 A. Meiksin , G. Bryan , M. Machacek

Lyman-alpha absorption is a prominent cosmological tool for probing both galactic halos and the intergalactic medium at high redshift. We consider a variety of sources that can be used as the Lyman-alpha emitters for this purpose. Among…

Astrophysics · Physics 2009-11-07 Rennan Barkana , Abraham Loeb

Coded aperture is a promising approach for capturing the 4-D light field (LF), in which the 4-D data are compressively modulated into 2-D coded measurements that are further decoded by reconstruction algorithms. The bottleneck lies in the…

Image and Video Processing · Electrical Eng. & Systems 2020-07-24 Mantang Guo , Junhui Hou , Jing Jin , Jie Chen , Lap-Pui Chau

The Reverse Zeldovich Approximation (RZA) is a reconstruction method which allows to estimate the cosmic displacement field from galaxy peculiar velocity data and to constrain initial conditions for cosmological simulations of the Local…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Timur Doumler , Helene Courtois , Stefan Gottloeber , Yehuda Hoffman

Visual retrieval systems face significant challenges when updating models with improved representations due to misalignment between the old and new representations. The costly and resource-intensive backfilling process involves…

Computer Vision and Pattern Recognition · Computer Science 2024-08-19 Simone Ricci , Niccolò Biondi , Federico Pernici , Alberto Del Bimbo

We investigate the properties of the Lyman alpha forest as predicted by numerical simulations for a range of currently viable cosmological models. This is done in order to understand the dependencies of the forest on cosmological…

Astrophysics · Physics 2009-10-31 M. E. Machacek , G. L. Bryan , A. Meiksin , P. Anninos , D. Thayer , M. L. Norman , Y. Zhang

Recent studies have focused on the low-$z$ Ly$\alpha$ forest as a potential constraint on galactic feedback, as different AGN and stellar feedback models in hydrodynamic simulations produce varying intergalactic medium (IGM) statistics.…

Astrophysics of Galaxies · Physics 2025-08-26 Megan T. Tillman , Joseph N. Burchett , Blakesley Burkhart , Vikram Khaire , Sanchayeeta Borthakur

We use the probability distribution function (PDF) of the lya forest flux at z=2-3, measured from high-resolution UVES/VLT data, and hydrodynamical simulations to obtain constraints on cosmological parameters and the thermal state of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 M. Viel , J. S. Bolton , M. G. Haehnelt

Several Wide Field of view Adaptive Optics (WFAO) concepts like Multi-Conjugate AO (MCAO), Multi-Object AO (MOAO) or Ground-Layer AO (GLAO) are currently studied for the next generation of Extremely Large Telescopes (ELTs). All these…

Astrophysics · Physics 2009-11-13 B. Neichel , T. Fusco , J. -M. Conan

We extend our super-resolution and emulation framework for cosmological dark matter simulations to include hydrodynamics. We present a two-stage deep learning model to emulate high-resolution (HR-HydroSim) baryonic fields from…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-23 Fatemeh Hafezianzadeh , Xiaowen Zhang , Yueying Ni , Rupert A. C. Croft , Tiziana DiMatteo , Mahdi Qezlou , Simeon Bird

The fluctuating Gunn-Peterson approximation (FGPA) is a commonly-used method to generate mock Lyman-$\alpha$ (Ly$\alpha$) forest absorption skewers at Cosmic Noon ($z\gtrsim 2$) from the matter-density field of $N$-body simulations without…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-26 Robin Kooistra , Khee-Gan Lee , Benjamin Horowitz

We measure the amount of absorption in the Lyman-alpha forest at 0 < z < 1.6 in HST FOS spectra of 74 QSOs. At 0 < z < 1.6 we find that 79% of the absorption is from the low density intergalactic medium, 12% from metals and 9% from the…

Astrophysics · Physics 2009-11-11 David Kirkman , David Tytler , Dan Lubin , Jane Charlton

It has been realised only recently that TeV emission from blazars can significantly heat the intergalactic medium (IGM) by pair-producing high-energy electrons and positrons, which in turn excite vigorous plasma instabilities, leading to a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Ewald Puchwein , Christoph Pfrommer , Volker Springel , Avery E. Broderick , Philip Chang

Peculiar velocities, obtained from direct distance measurements, are data of choice to achieve constrained simulations of the Local Universe reliable down to a scale of a few Megaparsecs. Unlike redshift surveys, peculiar velocities are…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Jenny G. Sorce , Helene M. Courtois , Stefan Gottloeber , Yehuda Hoffman , R. Brent Tully

Cosmological information is usually extracted from the Lyman-$\alpha$ forest correlations using only either large-scale information interpreted through linear theory or using small-scale information interpreted by means of expensive…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-14 Solène Chabanier , Corentin Ravoux , Lucas Latrille , Jean Sexton , Éric Armengaud , Julian Bautista , Tyann Dumerchat , Zarija Lukić
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