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We present a cosmic density field reconstruction method that augments the traditional reconstruction algorithms with a convolutional neural network (CNN). Following Shallue $\&$ Eisenstein (2022), the key component of our method is to use…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-05 Xinyi Chen , Fangzhou Zhu , Sasha Gaines , Nikhil Padmanabhan

Reconstructing the initial density field of the Universe from the late-time matter distribution is a nontrivial task with implications for understanding structure formation in cosmology, offering insights into early Universe conditions.…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-26 Koichiro Nakashima , Kiyotomo Ichiki , Atsushi J. Nishizawa , Kenji Hasegawa

We apply nonlinear reconstruction to the dark matter density field in redshift space and solve for the nonlinear mapping from the initial Lagrangian position to the final redshift space position. The reconstructed anisotropic field inferred…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-13 Hong-Ming Zhu , Yu Yu , Ue-Li Pen

We introduce a novel method for reconstructing the projected matter distributions of galaxy clusters with weak-lensing (WL) data based on convolutional neural network (CNN). Training datasets are generated with ray-tracing through…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-30 Sungwook E. Hong , Sangnam Park , M. James Jee , Dongsu Bak , Sangjun Cha

Traditional weak-lensing mass reconstruction techniques suffer from various artifacts, including noise amplification and the mass-sheet degeneracy. In Hong et al. (2021), we demonstrated that many of these pitfalls of traditional mass…

Astrophysics of Galaxies · Physics 2025-02-27 Sangjun Cha , M. James Jee , Sungwook E. Hong , Sangnam Park , Dongsu Bak , Taehwan kim

We present an iterative method to reconstruct the linear-theory initial conditions from the late-time cosmological matter density field, with the intent of improving the recovery of the cosmic distance scale from the baryon acoustic…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-05 Ryuichiro Hada , Daniel J. Eisenstein

We develop a machine learning approach to reconstructing the cosmological initial conditions from late-time dark matter halo number density fields in redshift space, with the goal of improving sensitivity to cosmological parameters, and in…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-15 Jelte Bottema , Thomas Flöss , P. Daniel Meerburg

With the advent of next-generation surveys and the expectation of discovering huge numbers of strong gravitational lens systems, much effort is being invested into developing automated procedures for handling the data. The several orders of…

Astrophysics of Galaxies · Physics 2021-02-17 Jacob Maresca , Simon Dye , Nan Li

Convolutional Neural Networks (CNNs) have recently been applied to cosmological fields -- weak lensing mass maps and galaxy maps. However, cosmological maps differ in several ways from the vast majority of images that CNNs have been tested…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-05 Kunhao Zhong , Marco Gatti , Bhuvnesh Jain

Initial density distribution provides a basis for understanding the complete evolution of cosmological density fluctuations. While reconstruction in our local Universe exploits the observations of galaxy surveys with large volumes,…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-28 Meng Zhou , Yi Mao

At high redshift, due to both observational limitations and the variety of galaxy morphologies in the early universe, measuring galaxy structure can be challenging. Non-parametric measurements such as the CAS system have thus become an…

Astrophysics of Galaxies · Physics 2021-09-08 C. Tohill , L. Ferreira , C. J. Conselice , S. P. Bamford , F. Ferrari

The prospect of nonparametric reconstructions of cosmological parameters from observational data sets has been a popular topic in the literature for a number of years. This has mainly taken the form of a technique based on Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-24 Konstantinos Dialektopoulos , Jackson Levi Said , Jurgen Mifsud , Joseph Sultana , Kristian Zarb Adami

In this work, we seek to improve the velocity reconstruction of clusters by using Graph Neural Networks -- a type of deep neural network designed to analyze sparse, unstructured data. In comparison to the Convolutional Neural Network (CNN)…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-23 Hideki Tanimura , Albert Bonnefous , Jia Liu , Sanmay Ganguly

We study the use of U-Nets in reconstructing the linear dark matter density field and its consequences for constraining cosmological parameters, in particular primordial non-Gaussianity. Our network is able to reconstruct the initial…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-23 Thomas Flöss , P. Daniel Meerburg

We present and test a new method for the reconstruction of cosmological initial conditions from a full-sky galaxy catalogue. This method, called ZTRACE, is based on a self-consistent solution of the growing mode of gravitational…

Astrophysics · Physics 2009-10-31 P. Monaco , G. Efstathiou

Next-generation cosmic microwave background (CMB) experiments will have lower noise and therefore increased sensitivity, enabling improved constraints on fundamental physics parameters such as the sum of neutrino masses and the…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-16 João Caldeira , W. L. Kimmy Wu , Brian Nord , Camille Avestruz , Shubhendu Trivedi , Kyle T. Story

We present a new method to reconstruct the primordial (linear) density field using the estimated nonlinear displacement field. The divergence of the displacement field gives the reconstructed density field. We solve the nonlinear…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-23 Hong-Ming Zhu , Ue-Li Pen , Xuelei Chen

We present a method to reconstruct the initial conditions of the universe using observed galaxy positions and luminosities under the assumption that the luminosities can be calibrated with weak lensing to give the mean halo mass. Our method…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-24 Chirag Modi , Yu Feng , Uros Seljak

We develop a deep learning technique to infer the non-linear velocity field from the dark matter density field. The deep learning architecture we use is an "U-net" style convolutional neural network, which consists of 15 convolution layers…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-21 Ziyong Wu , Zhenyu Zhang , Shuyang Pan , Haitao Miao , Xin Wang , Cristiano G. Sabiu , Jaime Forero-Romero , Yang Wang , Xiao-Dong Li

We present a direct approach to nonparametrically reconstruct the linear density field from an observed nonlinear map. We solve for the unique displacement potential consistent with the nonlinear density and positive definite coordinate…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-25 Hong-Ming Zhu , Yu Yu , Ue-Li Pen , Xuelei Chen , Hao-Ran Yu
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