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One of the primary limiting sources of systematic uncertainty in forthcoming weak lensing measurements is systematic uncertainty in the quantitative relationship between the distortions due to gravitational lensing and the measurable…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-10 Eric Huff , Rachel Mandelbaum

Identifying the underlying models in a set of data points contaminated by noise and outliers, leads to a highly complex multi-model fitting problem. This problem can be posed as a clustering problem by the projection of higher order…

Computer Vision and Pattern Recognition · Computer Science 2018-08-01 Ruwan Tennakoon , Alireza Sadri , Reza Hoseinnezhad , Alireza Bab-Hadiashar

We perform a galaxy-galaxy lensing study by correlating the shapes of $\sim$2.7 $\times$ 10$^5$ galaxies selected from the VLA FIRST radio survey with the positions of $\sim$38.5 million SDSS galaxies, $\sim$132000 BCGs and $\sim$78000 SDSS…

Astrophysics of Galaxies · Physics 2018-05-04 Constantinos Demetroullas , Michael L. Brown

We present AMICO (Adaptive Matched Identifier of Clustered Objects), a new algorithm for the detection of galaxy clusters in photometric surveys. AMICO is based on the Optimal Filtering technique, which allows to maximise the…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-13 Fabio Bellagamba , Mauro Roncarelli , Matteo Maturi , Lauro Moscardini

We investigate how galaxy pairs are oriented in three dimensions within cosmic filaments using data from the EAGLE simulation. We identify filament spines using DisPerSE and isolate galaxies residing in filamentary environments. Employing a…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Suman Sarkar , Biswajit Pandey

We test the cosmological implications of studying galaxy clustering using a tomographic approach, by computing the galaxy two-point angular correlation function $\omega(\theta)$ in thin redshift shells using a spectroscopic-redshift galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Salvador Salazar-Albornoz , Ariel G. Sánchez , Nelson D. Padilla , Carlton M. Baugh

Deconvolution of large survey images with millions of galaxies requires to develop a new generation of methods which can take into account a space variant Point Spread Function (PSF) and have to be at the same time accurate and fast. We…

Instrumentation and Methods for Astrophysics · Physics 2020-09-16 Florent Sureau , Alexis Lechat , Jean-Luc Starck

We present a two-dimensional (2-D) fitting algorithm (GALFIT, Version 3) with new capabilities to study the structural components of galaxies and other astronomical objects in digital images. Our technique improves on previous 2-D fitting…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Chien Y. Peng , Luis C. Ho , Chris D. Impey , Hans-Walter Rix

Accurate modeling of galaxy distributions is paramount for cosmological analysis using galaxy redshift surveys. However, this endeavor is often hindered by the computational complexity of resolving the dark matter halos that host these…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-07 J. M. Coloma-Nadal , F. -S. Kitaura , J. E. García-Farieta , F. Sinigaglia , G. Favole , D. Forero Sánchez

Photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-15 J. Asorey , M. Carrasco Kind , I. Sevilla-Noarbe , R. J. Brunner , J. Thaler

Weak gravitational lensing has been used extensively in the past decade to constrain the masses of galaxy clusters, and is the most promising observational technique for providing the mass calibration necessary for precision cosmology with…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Rachel Mandelbaum , Uros Seljak , Tobias Baldauf , Robert E. Smith

Methods for compression and classification of galaxy spectra, which are useful for large galaxy redshift surveys (such as the SDSS, 2dF, 6dF and VIRMOS), are reviewed. In particular, we describe and contrast three methods: (i) Principal…

Astrophysics · Physics 2009-10-31 Ofer Lahav

A direct approach to studying the galaxy-halo connection is to analyze groups and clusters of galaxies that trace the underlying dark matter halos, emphasizing the importance of identifying galaxy clusters and their associated brightest…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-22 Hai-Xia Ma , Tsutomu T. Takeuchi , Suchetha Cooray , Yongda Zhu

We present the 2-degree Field Lensing Survey (2dFLenS), a new galaxy redshift survey performed at the Anglo-Australian Telescope. 2dFLenS is the first wide-area spectroscopic survey specifically targeting the area mapped by deep-imaging…

The Bayesian gravitational shear estimation algorithm developed by Bernstein and Armstrong (2014) can potentially be used to overcome multiplicative noise bias and recover shear using very low signal-to-noise ratio (S/N) galaxy images. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Erin S. Sheldon

Galaxies are arranged in interconnected walls and filaments forming a cosmic web encompassing huge, nearly empty, regions between the structures. Many statistical methods have been proposed in the past in order to describe the galaxy…

Astrophysics · Physics 2016-02-17 J-L. Starck , V. J. Martinez , D. L. Donoho , O. Levi , P. Querre , E. Saar

High-dimensional simulation optimization is notoriously challenging. We propose a new sampling algorithm that converges to a global optimal solution and suffers minimally from the curse of dimensionality. The algorithm consists of two…

Machine Learning · Statistics 2021-07-21 Liang Ding , Rui Tuo , Xiaowei Zhang

During the last decade, there has been an explosive growth in survey data and deep learning techniques, both of which have enabled great advances for astronomy. The amount of data from various surveys from multiple epochs with a wide range…

Instrumentation and Methods for Astrophysics · Physics 2021-02-08 Brandon Buncher , Awshesh Nath Sharma , Matias Carrasco Kind

We study projected underdensities in the cosmic galaxy density field known as 'troughs', and their overdense counterparts, which we call 'ridges'. We identify these regions using a bright sample of foreground galaxies from the photometric…

Recent cosmological analyses with large-scale structure and weak lensing measurements, usually referred to as 3$\times$2pt, had to discard a lot of signal-to-noise from small scales due to our inability to accurately model non-linearities…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-26 J. Prat , G. Zacharegkas , Y. Park , N. MacCrann , E. R. Switzer , S. Pandey , C. Chang , J. Blazek , R. Miquel , A. Alarcon , O. Alves , A. Amon , F. Andrade-Oliveira , K. Bechtol , M. R. Becker , G. M. Bernstein , R. Chen , A. Choi , H. Camacho , A. Campos , A. Carnero Rosell , M. Carrasco Kind , R. Cawthon , J. Cordero , M. Crocce , C. Davis , J. DeRose , H. T. Diehl , S. Dodelson , C. Doux , A. Drlica-Wagner , K. Eckert , T. F. Eifler , J. Elvin-Poole , S. Everett , X. Fang , A. Ferté , P. Fosalba , O. Friedrich , M. Gatti , G. Giannini , D. Gruen , R. A. Gruendl , I. Harrison , W. G. Hartley , K. Herner , H. Huang , E. M. Huff , M. Jarvis , E. Krause , N. Kuropatkin , P. -F. Leget , J. McCullough , J. Myles , A. Navarro-Alsina , A. Porredon , M. Raveri , R. P. Rollins , A. Roodman , R. Rosenfeld , A. J. Ross , E. S. Rykoff , C. Sánchez , J. Sanchez , L. F. Secco , I. Sevilla-Noarbe , E. Sheldon , T. Shin , M. A. Troxel , I. Tutusaus , T. N. Varga , B. Yanny , B. Yin , Y. Zhang , J. Zuntz , M. Aguena , S. Allam , J. Annis , D. Bacon , E. Bertin , S. Bocquet , D. Brooks , D. L. Burke , J. Carretero , M. Costanzi , M. E. S. Pereira , J. De Vicente , S. Desai , I. Ferrero , B. Flaugher , D. W. Gerdes , G. Gutierrez , S. R. Hinton , D. L. Hollowood , K. Honscheid , D. J. James , M. Lima , F. Menanteau , J. Mena-Fernández , A. Palmese , M. Paterno , F. Paz-Chinchón , A. Pieres , A. A. Plazas Malagón , M. Rodriguez-Monroy , E. Sanchez , M. Schubnell , M. Smith , M. Soares-Santos , E. Suchyta , M. E. C. Swanson , G. Tarle , C. To , N. Weaverdyck , J. Weller