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The comparison of quasar absorption spectra with numerically simulated spectra from hierarchical cosmological models of structure formation promises to be a valuable tool to discriminate among these models. We present simulation results for…

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

We give a comprehensive statistical description of the Lyman-alpha absorption from the intergalactic medium in a hydrodynamic simulation at redshifts 0.1-1.6, the range of redshifts covered by HST spectra of QSOs. We use the ENZO code to…

Astrophysics · Physics 2015-05-13 Pascal Paschos , Tridivesh Jena , David Tytler , David Kirkman , Michael L. Norman

Motivated by the work of Uehara et al. [1], an improved method to recover DC coefficients from AC coefficients of DCT-transformed images is investigated in this work, which finds applications in cryptanalysis of selective multimedia…

Multimedia · Computer Science 2015-03-13 Shujun Li , Junaid Jameel Ahmad , Dietmar Saupe , C. -C. Jay Kuo

We present a new Unbiased Minimal Variance (UMV) estimator for the purpose of reconstructing the large--scale structure of the universe from noisy, sparse and incomplete data. Similar to the Wiener Filter (WF), the UMV estimator is derived…

Astrophysics · Physics 2009-10-31 Saleem Zaroubi

We present a determination of the bispectrum of the flux in the Lyman-alpha forest of QSO absorption spectra obtained from LUQAS which consists of spectra observed with the high resolution Echelle spectrograph UVES. Typical errors on the…

Astrophysics · Physics 2009-11-10 M. Viel , S. Matarrese , A. Heavens , M. G. Haehnelt , T. -S. Kim , V. Springel , L. Hernquist

In recent years, a remarkably simple physical picture of the Lyman-alpha forest has emerged, which allows detailed predictions to be made and turns the forest into a powerful probe of cosmology. We point out ways in which such a picture can…

Astrophysics · Physics 2007-05-23 Lam Hui

The hydrogen Ly$\alpha$ forest is an important probe of the $z>2$ Universe that is otherwise challenging to observe with galaxy redshift surveys, but this technique has traditionally been limited to 1D studies in front of bright quasars.…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 Khee-Gan Lee

We propose a new method for fitting the full-shape of the Lyman-$\alpha$ (Ly$\alpha$) forest three-dimensional (3D) correlation function in order to measure the Alcock-Paczynski (AP) effect. Our method preserves the robustness of baryon…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-25 Andrei Cuceu , Andreu Font-Ribera , Benjamin Joachimi , Seshadri Nadathur

The inference of astrophysical and cosmological properties from the Lyman-$\alpha$ forest conventionally relies on summary statistics of the transmission field that carry useful but limited information. We present a deep learning framework…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-11 Parth Nayak , Michael Walther , Daniel Gruen , Sreyas Adiraju

Galactic outflows are critical to our understanding of galaxy formation and evolution. However the details of the underlying feedback process remain unclear. We compare Ly$\alpha$ observations of the circumgalactic medium (CGM) of Lyman…

Astrophysics of Galaxies · Physics 2019-01-23 Andrew S. Chung , Mark Dijkstra , Benedetta Ciardi , Koki Kakiichi , Thorsten Naab

We propose a combined reconstruction-classification method for simultaneously recovering absorption and scattering in turbid media from images of absorbed optical energy. This method exploits knowledge that optical parameters are determined…

Medical Physics · Physics 2016-01-20 Emma Malone , Samuel Powell , Ben T. Cox , Simon R. Arridge

Cosmological hydrodynamic simulations can accurately predict the properties of the intergalactic medium (IGM), but only under the condition of retaining high spatial resolution necessary to resolve density fluctuations in the IGM. This…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-17 Daniele Sorini , José Oñorbe , Zarija Lukić , Joseph F. Hennawi

The forest of Lyman-$\alpha$ absorption lines detected in the spectra of distant quasars encodes information on the nature and properties of dark matter and the thermodynamics of diffuse baryonic material. Its main observable -- the 1D flux…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-19 Bruno Villasenor , Brant Robertson , Piero Madau , Evan Schneider

In previous works we proposed the Reverse Zeldovich Approximation (RZA) method, which can be used to estimate the cosmological initial conditions underlying the galaxy distribution in the Local Universe using peculiar velocity data. In this…

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

Full-physics cosmological simulations are powerful tools for studying the formation and evolution of structure in the universe but require extreme computational resources. Here, we train a convolutional neural network to use a cheaper…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-04 Peter Harrington , Mustafa Mustafa , Max Dornfest , Benjamin Horowitz , Zarija Lukić

We extend our previously proposed image reconstruction method, which allows confocal microscopes to capture periodically moving objects at frequencies beyond their frame rates, to three-dimensional and two-dimensional wide-field imaging.…

Optics · Physics 2026-03-03 Kanta Adachi , Soyoka Hemmi , Nobutomo Nakamura

In preparation for the IGM tomography study by Subaru Prime Focus Spectrograph (PFS) survey and other large future telescopes such as TMT/ELT/GMT, we present the results of our pilot study on Ly$\alpha$ forest and IGM tomography statistics…

Advancements in synthesized speech have created a growing threat of impersonation, making it crucial to develop deepfake algorithm recognition. One significant aspect is out-of-distribution (OOD) detection, which has gained notable…

Audio and Speech Processing · Electrical Eng. & Systems 2024-06-05 Renmingyue Du , Jixun Yao , Qiuqiang Kong , Yin Cao

We propose a novel compressed sensing method to improve the depth reconstruction accuracy and multi-target separation capability of indirect Time-of-Flight (iToF) systems. Unlike traditional approaches that rely on hardware modifications,…

Signal Processing · Electrical Eng. & Systems 2025-07-29 Yansong Du , Yutong Deng , Yuting Zhou , Feiyu Jiao , Bangyao Wang , Zhancong Xu , Zhaoxiang Jiang , Xun Guan

We identify a concordant model for the intergalactic medium (IGM) at redshift z=1.9 that uses popular values for cosmological and astrophysical parameters and accounts for all baryons with an uncertainty of 6%. We have measured the amount…