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Identifying galaxy groups from redshift surveys of galaxies plays an important role in connecting galaxies with the underlying dark matter distribution. Current and future high-$z$ spectroscopic surveys, usually incomplete in redshift…

Astrophysics of Galaxies · Physics 2020-10-14 Kai Wang , H. J. Mo , Cheng Li , Jiacheng Meng , Yangyao Chen

We present a newly developed code that allows simulations of optical observations of galaxy fields with a variety of instruments. The code incorporates gravitational lensing effects and is targetted at simulating lensing by galaxy clusters.…

Many catalogues of isolated compact groups of galaxies (CGs) have been extracted using Hickson's criteria to identify isolated, dense systems of galaxies, with at least three or four galaxies concordant in magnitude and redshift. But is not…

Astrophysics of Galaxies · Physics 2022-02-09 Antonela Taverna , Eugenia Diaz-Gimenez , Ariel Zandivarez , Gary Mamon

Spectropolarimetry, the observation of polarization and intensity as a function of wavelength, is a powerful tool in stellar astrophysics. It is particularly useful for characterizing stars and circumstellar material, and for tracing the…

Characterising galaxy cluster populations from catalog of sources selected in astronomical surveys requires knowledge of sample incompleteness, known as selection function. The first All-Sky Survey (eRASS1) by eROSITA onboard Spectrum…

A new luminosity function for galaxies can be built starting from the product of two random variables X and Y represented by a gamma variate with argument 2 >. The mean, the standard deviation and the distribution function of this new…

Astrophysics · Physics 2009-06-30 L. Zaninetti

The wolensing Python package offers a solution for gravitational wave lensing computations within the full wave-optics regime. This tool is primarily designed to calculate the gravitational lensing amplification factor including diffractive…

Instrumentation and Methods for Astrophysics · Physics 2024-10-29 Simon M. C. Yeung , Mark H. Y. Cheung , Miguel Zumalacarregui , Otto A. Hannuksela

Gravitational lensing induces significant errors in the measured distances to high-redshift standard candles and standard sirens such as type-Ia supernovae, gamma-ray bursts, and merging supermassive black hole binaries. There will…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Stefan Hilbert , Jonathan R. Gair , Lindsay J. King

We show how precision lensing measurements can be obtained through the lensing magnification effect in high redshift 21cm emission from galaxies. Normally, cosmic magnification measurements have been seriously complicated by galaxy…

Astrophysics · Physics 2009-11-11 Pengjie Zhang , Ue-Li Pen

Gravitational lensing occurs as the path of light from distant celestial bodies is distorted due to gravitational attraction by other celestial bodies, whose mass is partly invisible, being so-called dark matter. When observed through a…

Instrumentation and Methods for Astrophysics · Physics 2024-05-29 Hans Georg Schaathun , Ben David Normann , Kenny Solevåg-Hoti

We use an automated galaxy morphology analysis method to quantitatively measure the spirality of galaxies classified manually as elliptical. The data set used for the analysis consists of 60,518 galaxy images with redshift obtained by the…

Astrophysics of Galaxies · Physics 2015-06-17 Levente Dojcsak , Lior Shamir

Gaia is a fully-approved all-sky astrometric and photometric survey due for launch in 2011. It will measure accurate parallaxes and proper motions for everything brighter than G=20 (ca. 10^9 stars). Its primary objective is to study the…

Astrophysics · Physics 2007-05-23 Coryn A. L. Bailer-Jones

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

We have performed a detailed analysis of the ability of the friends-of-friends algorithm in identifying real galaxy systems in deep surveys such as the future Javalambre Physics of the Accelerating Universe Astrophysical Survey. Our…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 A. Zandivarez , E. Díaz-Giménez , C. Mendes de Oliveira , B. Ascaso , N. Benítez , R. Dupke , L. Sodré , . , J. Irwin

We describe a method for estimating the power spectrum of density fluctuations from galaxy redshift surveys that yields improvement in both accuracy and resolution over direct Fourier analysis. The key feature of this analysis is expansion…

Astrophysics · Physics 2009-10-28 Michael S. Vogeley , Alexander S. Szalay

Reliable extraction of cosmological information from clustering measurements of galaxy surveys requires estimation of the error covariance matrices of observables. The accuracy of covariance matrices is limited by our ability to generate…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-29 Mohammadjavad Vakili , Francisco-Shu Kitaura , Yu Feng , Gustavo Yepes , Cheng Zhao , Chia-Hsun Chuang , ChangHoon Hahn

We present a far-infrared galaxy luminosity function for the local universe. We have obtained 389 spectroscopic redshifts for galaxies observed at 90 microns in the AKARI Deep Field South, using the AAOmega fibre spectrograph via optical…

We present a new scheme, $\it{galtag}$, for refining the photometric redshift measurements of faint galaxies by probabilistically tagging them to observed galaxy groups constructed from a brighter, magnitude-limited spectroscopy survey.…

Astrophysics of Galaxies · Physics 2018-07-04 P. R. Kafle , A. S. G. Robotham , S. P. Driver , S. Deeley , P. Norberg , M. J. Drinkwater , L. J. Davies

We have carried out targetted sub-mm observations as part of a programme to explore the connection between the rest-frame UV and far-IR properties of star-forming galaxies at high redshift, which is currently poorly understood. On the one…

We examine the improvements in constraints on the linear growth factor G and its derivative f=d ln G / dln a that are available from the combination of a large-scale galaxy redshift survey with a weak gravitational lensing survey of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Gary M. Bernstein , Yan-Chuan Cai
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