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Gravitational lensing directly measures mass density fluctuations along the lines of sight to very distant objects. No assumptions need to be made concerning bias, the ratio of fluctuations in galaxy density to mass density. Hence, lensing…

天体物理学 · 物理学 2007-05-23 Joachim Wambsganss , Renyue Cen , Jeremiah P. Ostriker

Next-generation surveys will provide photometric and spectroscopic data of millions to billions of galaxies with unprecedented precision. This offers a unique chance to improve our understanding of the galaxy evolution and the unresolved…

Galaxy redshift surveys can be used to detect gravitationally-lensed quasars if the spectra obtained are searched for the quasars' emission lines. Previous investigations of this possibility have used simple models to show that the 2 degree…

天体物理学 · 物理学 2008-11-26 Daniel J. Mortlock , Rachel L. Webster

The generalised linear model (GLM) is a very important tool for analysing real data in biology, sociology, agriculture, engineering and many other application domain where the relationship between the response and explanatory variables may…

统计方法学 · 统计学 2016-07-04 Abhik Ghosh , Ayanendranath Basu

Classification is a popular task in the field of Machine Learning (ML) and Artificial Intelligence (AI), and it happens when outputs are categorical variables. There are a wide variety of models that attempts to draw some conclusions from…

天体物理仪器与方法 · 物理学 2023-02-24 Mohammad H. Zhoolideh Haghighi

We conduct a comprehensive study of the effects of incorporating galaxy morphology information in photometric redshift estimation. Using machine learning methods, we assess the changes in the scatter and catastrophic outlier fraction of…

We present the first results of our application of photometric redshifts to the study of galaxy populations in high-redshift clusters. For this survey, we are examining a sample of galaxy clusters at z > 0.6 which have already been…

天体物理学 · 物理学 2007-05-23 L. M. Lubin , R. J. Brunner

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…

星系天体物理 · 物理学 2020-10-14 Kai Wang , H. J. Mo , Cheng Li , Jiacheng Meng , Yangyao Chen

The availability of large, public, multi-modal astronomical datasets presents an opportunity to execute novel research that straddles the line between science of AI and science of astronomy. Photometric redshift estimation is a…

天体物理仪器与方法 · 物理学 2024-02-07 Andrew Engel , Gautham Narayan , Nell Byler

The widespread dissemination of machine learning tools in science, particularly in astronomy, has revealed the limitation of working with simple single-task scenarios in which any task in need of a predictive model is looked in isolation,…

高能天体物理现象 · 物理学 2018-12-27 Ricardo Vilalta

Mismodeling the uncertain, diffuse emission of Galactic origin can seriously bias the characterization of astrophysical gamma-ray data, particularly in the region of the Inner Milky Way where such emission can make up over 80% of the photon…

高能天体物理现象 · 物理学 2020-10-21 Siddharth Mishra-Sharma , Kyle Cranmer

Classification of intermediate redshift ($z$ = 0.3--0.8) emission line galaxies as star-forming galaxies, composite galaxies, active galactic nuclei (AGN), or low-ionization nuclear emission regions (LINERs) using optical spectra alone was…

This study aims to improve the photometric redshifts (photo-$z$s) of galaxies by integrating two contemporary methods: template-fitting and machine learning. Finding the synergy between these two methods was not a high priority in the past,…

宇宙学与河外天体物理 · 物理学 2023-11-30 Ishaq Y. K. Alshuaili , John Y. H. Soo , Mohd Zubir Mat Jafri , Yasmin Rafid

This work uses hierarchical logistic Gaussian processes to infer true redshift distributions of samples of galaxies, through their cross-correlations with spatially overlapping spectroscopic samples. We demonstrate that this method can…

宇宙学与河外天体物理 · 物理学 2020-06-30 Markus Michael Rau , Simon Wilson , Rachel Mandelbaum

Gamma-ray bursts (GRBs) are intense, short-lived bursts of gamma-ray radiation observed up to a high redshift ($z \sim 10$) due to their luminosities. Thus, they can serve as cosmological tools to probe the early Universe. However, we need…

We present a convolutional neural network to classify distinct cosmological scenarios based on the statistically similar weak-lensing maps they generate. Modified gravity (MG) models that include massive neutrinos can mimic the standard…

宇宙学与河外天体物理 · 物理学 2019-07-17 Austin Peel , Florian Lalande , Jean-Luc Starck , Valeria Pettorino , Julian Merten , Carlo Giocoli , Massimo Meneghetti , Marco Baldi

We describe Ganalyzer, a model-based tool that can automatically analyze and classify galaxy images. Ganalyzer works by separating the galaxy pixels from the background pixels, finding the center and radius of the galaxy, generating the…

天体物理仪器与方法 · 物理学 2015-05-28 Lior Shamir

We present an analysis of a general machine learning technique called 'stacking' for the estimation of photometric redshifts. Stacking techniques can feed the photometric redshift estimate, as output by a base algorithm, back into the same…

天体物理仪器与方法 · 物理学 2016-07-27 Roman Zitlau , Ben Hoyle , Kerstin Paech , Jochen Weller , Markus Michael Rau , Stella Seitz

Rare extragalactic objects can carry substantial information about the past, present, and future universe. Given the size of astronomical databases in the information era it can be assumed that very many outlier galaxies are included in…

星系天体物理 · 物理学 2021-01-13 Lior Shamir

Photometric redshifts (photo-z's) are fundamental in galaxy surveys to address different topics, from gravitational lensing and dark matter distribution to galaxy evolution. The Kilo Degree Survey (KiDS), i.e. the ESO public survey on the…