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Related papers: Redshift determination through weighted phase corr…

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We present estimates of the N-point galaxy, area-averaged, angular correlation functions $\bar{\omega}_{N}$($\theta$) for $N$ = 2,...,7 for galaxies from the fifth data release of the Sloan Digital Sky Survey. Our parent sample is selected…

Astrophysics · Physics 2009-11-13 Ashley J. Ross , Robert J. Brunner , Adam D. Myers

We improve the running times of $O(1)$-approximation algorithms for the set cover problem in geometric settings, specifically, covering points by disks in the plane, or covering points by halfspaces in three dimensions. In the unweighted…

Computational Geometry · Computer Science 2020-03-31 Timothy M. Chan , Qizheng He

We consider stochastic approximation for the least squares regression problem in the non-strongly convex setting. We present the first practical algorithm that achieves the optimal prediction error rates in terms of dependence on the noise…

Machine Learning · Computer Science 2022-03-04 Aditya Varre , Nicolas Flammarion

The aim of sparse phase retrieval is to recover a $k$-sparse signal $\mathbf{x}_0\in \mathbb{C}^{d}$ from quadratic measurements $|\langle \mathbf{a}_i,\mathbf{x}_0\rangle|^2$ where $\mathbf{a}_i\in \mathbb{C}^d, i=1,\ldots,m$. Noting…

Functional Analysis · Mathematics 2021-05-05 Yu Xia , Zhiqiang Xu

We develop a cosmological parameter estimation code for (tomographic) angular power spectra analyses of galaxy number counts, for which we include, for the first time, redshift-space distortions (RSD) in the Limber approximation. This…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-15 Konstantinos Tanidis , Stefano Camera

The weighted nonlinear least-squares problem for low-rank signal estimation is considered. The problem of constructing a numerical solution that is stable and fast for long time series is addressed. A modified weighted Gauss-Newton method,…

Numerical Analysis · Mathematics 2022-07-08 Nikita Zvonarev , Nina Golyandina

Linear regression is a basic and widely-used methodology in data analysis. It is known that some quantum algorithms efficiently perform least squares linear regression of an exponentially large data set. However, if we obtain values of the…

Quantum Physics · Physics 2021-08-27 Kazuya Kaneko , Koichi Miyamoto , Naoyuki Takeda , Kazuyoshi Yoshino

We improve a phase retrieval approach that uses correlation-based measurements with compactly supported measurement masks [27]. The improved algorithm admits deterministic measurement constructions together with a robust, fast recovery…

Numerical Analysis · Mathematics 2016-12-07 Mark A. Iwen , Brian Preskitt , Rayan Saab , Aditya Viswanathan

We present a catalogue of galaxy photometric redshifts and k-corrections for the Sloan Digital Sky Survey Seven Data Release (SDSS-DR7), available on the World Wide Web. The photometric redshifts were estimated with an artificial neural…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Ana Laura O'Mill , Fernanda Duplancic , Diego García Lambas , Laerte Sodré

Accurate estimation of photometric redshifts (photo-$z$) is crucial in studies of both galaxy evolution and cosmology using current and future large sky surveys. In this study, we employ Random Forest (RF), a machine learning algorithm, to…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-27 Junhao Lu , Zhijian Luo , Zhu Chen , Liping Fu , Wei Du , Yan Gong , Yicheng Li , Xian-Min Meng , Zhirui Tang , Shaohua Zhang , Chenggang Shu , Xingchen Zhou , Zuhui Fan

Discrete Fourier analysis on the quasar number count, as a function of redshift, $z$, calculated from the Sloan Digital Sky Survey DR6 release appears to indicate that quasars have preferred periodic redshifts with redshift intervals of…

Astrophysics · Physics 2010-04-14 John G. Hartnett

In this paper, we consider the sparse phase retrieval problem, recovering an $s$-sparse signal $\bm{x}^{\natural}\in\mathbb{R}^n$ from $m$ phaseless samples $y_i=|\langle\bm{x}^{\natural},\bm{a}_i\rangle|$ for $i=1,\ldots,m$. Existing…

Numerical Analysis · Mathematics 2021-10-15 Jian-Feng Cai , Jingzhi Li , Xiliang Lu , Juntao You

Future baryon acoustic oscillation (BAO) surveys will survey very large volumes, covering wide ranges in redshift. We derive a set of redshift weights to compress the information in the redshift direction to a small number of modes. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-06 Fangzhou Zhu , Nikhil Padmanabhan , Martin White

Traditional photometric redshift methods use only color information about the objects in question to estimate their redshifts. This paper introduces a new method utilizing colors, luminosity, surface brightness, and radial light profile to…

Astrophysics · Physics 2008-11-26 James J. Wray , James E. Gunn

Stochastic spectral methods have achieved great success in the uncertainty quantification of many engineering problems, including electronic and photonic integrated circuits influenced by fabrication process variations. Existing techniques…

Numerical Analysis · Mathematics 2018-12-06 Chunfeng Cui , Zheng Zhang

The uncertainty in the photometric redshift estimation is one of the major systematics in weak lensing cosmology. The self-calibration method is able to reduce this systematics without assuming strong priors. We improve the recently…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-07 Hui Peng , Haojie Xu , Le Zhang , Zhao Chen , Yu Yu

We present an algorithm for selecting an uniform sample of gravitationally lensed quasar candidates from low-redshift (0.6<z<2.2) quasars brighter than i=19.1 that have been spectroscopically identified in the SDSS. Our algorithm uses…

We present a computationally efficient galaxy archetype-based redshift estimation and spectral classification method for the Dark Energy Survey Instrument (DESI) survey. The DESI survey currently relies on a redshift fitter and spectral…

We propose a new method to estimate the photometric redshift of galaxies by using the full galaxy image in each measured band. This method draws from the latest techniques and advances in machine learning, in particular Deep Neural…

Instrumentation and Methods for Astrophysics · Physics 2016-06-16 Ben Hoyle

Optical spectra of galaxies and quasars from large cosmological surveys are used to measure redshifts and infer distances. They are also rich with information on the intrinsic properties of these astronomical objects. However, their…