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We report the discovery of 31 new redshifted broad absorption line quasars (RSBALs) from the Sloan Digital Sky Survey (SDSS). The number of previously known such objects is 19. The identification of the new objects was enabled by…

Instrumentation and Methods for Astrophysics · Physics 2018-08-15 Itamar Reis , Dovi Poznanski , Patrick B. Hall

Obtaining accurate photometric redshift estimations is an important aspect of cosmology, remaining a prerequisite of many analyses. In creating novel methods to produce redshift estimations, there has been a shift towards using machine…

Instrumentation and Methods for Astrophysics · Physics 2021-07-07 Ben Henghes , Connor Pettitt , Jeyan Thiyagalingam , Tony Hey , Ofer Lahav

Weighted variants of triangle detection are an important object of study because of their prominence in fine-grained complexity. We revisit the Node-Weighted Triangle problem, where the goal is to decide if a vertex-weighted graph contains…

Data Structures and Algorithms · Computer Science 2026-05-12 Shyan Akmal , Nick Fischer

This paper presents a high-precision gravitational redshift test using the China Space Station (CSS) Laser Time Transfer (CLT) system. We develop a comprehensive observation equation based on a c^{-3} order relativistic model for…

General Relativity and Quantum Cosmology · Physics 2026-05-11 Rui Xu , Wenbin Shen , Hok Sum Fok , Pengfei Zhang , Lihong Li , Lei Wang , Kuangchao Wu , An Ning , Youchao Xie , Ziyu Shen , Lingxuan Wang , Yongqi Zhao , Kai Liu , Yuanjin Pan

We present a neural network based approach to the determination of photometric redshift. The method was tested on the Sloan Digital Sky Survey Early Data Release (SDSS-EDR) reaching an accuracy comparable and, in some cases, better than SED…

Much of the science that is made possible by multiwavelength redshift surveys requires the use of photometric redshifts. But as these surveys become more ambitious, and as we seek to perform increasingly accurate measurements, it becomes…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-23 Ryan F. Quadri , Rik J. Williams

We propose a new method for probing the time variation of the effective Newton's constant $G_{\rm eff}$, based on the optimal redshift weighting scheme, and demonstrate the efficacy using the DESI galaxy spectroscopic survey. We find that…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-03 Jian Li , Gong-Bo Zhao

This study investigates the anomalies associated with redshifts from emission lines in certain quasar candidates and the viability of a blueshift interpretation instead. The sample was taken from the Million Quasars Catalog (MILLIQUAS),…

Astrophysics of Galaxies · Physics 2024-04-16 Justin Singh , Shirin Haque

We have imaged 45 quasars from the Sloan Digital Sky Survey (SDSS) with redshifts 1.85 < z < 4.26 in JHKs with the KPNO SQIID imager. By combining these data with optical magnitudes from the SDSS we have computed the restframe optical…

Astrophysics · Physics 2009-11-13 Julia Kennefick , Shelly Bursick

Precision measurements of the galaxy power spectrum P(k) require a data analysis pipeline that is both fast enough to be computationally feasible and accurate enough to take full advantage of high-quality data. We present a rigorous…

Astrophysics · Physics 2009-10-07 Max Tegmark , Andrew Hamilton , Michael Strauss , Michael Vogeley , Alexander Szalay

This paper investigates the sparse phase retrieval problem, which aims to recover a sparse signal from a system of quadratic measurements. In this work, we propose a novel non-convex algorithm, termed Gradient Hard Thresholding Pursuit…

Numerical Analysis · Mathematics 2025-02-18 Licheng Dai , Xiliang Lu , Juntao You

A weighted regression procedure is proposed for regression type problems where the innovations are heavy-tailed. This method approximates the least absolute regression method in large samples, and the main advantage will be if the sample is…

Computation · Statistics 2018-11-06 J. Martin van Zyl

This paper investigates the convergence of the randomized Kaczmarz algorithm for the problem of phase retrieval of complex-valued objects. While this algorithm has been studied for the real-valued case}, its generalization to the…

Information Theory · Computer Science 2020-10-14 Teng Zhang , Feng Yu

Context. Computational techniques are essential for mining large databases produced in modern surveys with value-added products. Aims. This paper presents a machine learning procedure to carry out simultaneously galaxy morphological…

Machine learning techniques, specifically the k-nearest neighbour algorithm applied to optical band colours, have had some success in predicting photometric redshifts of quasi-stellar objects (QSOs): Although the mean of differences between…

Instrumentation and Methods for Astrophysics · Physics 2020-01-29 S. J. Curran

We modify the algorithm we proposed before in Aghamousa & Shafieloo (2015) on time delay estimation of the strong lens systems incorporating weighted cross-correlation and weighted summation of correlation coefficients. We show the high…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-23 Amir Aghamousa , Arman Shafieloo

Accurate photometric redshifts are among the key requirements for precision weak lensing measurements. Both the large size of the Sloan Digital Sky Survey (SDSS) and the existence of large spectroscopic redshift samples that are…

We provide a new efficient adaptive algorithm for performing phase estimation that does not require that the user infer the bits of the eigenphase in reverse order; rather it directly infers the phase and estimates the uncertainty in the…

Quantum Physics · Physics 2016-07-06 Nathan Wiebe , Christopher E Granade

Redshift-space distortions (RSD) offers an exciting opportunity to test the gravity on cosmological scales. In the presence of galaxy bias, however, the RSD measurement at large scales, where the linear theory prediction is safely applied,…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-25 Yong-Seon Song , Yi Zheng , Atsushi Taruya
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