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Photometric galaxy surveys probe the late-time Universe where the density field is highly non-Gaussian. A consequence is the emergence of the super-sample covariance (SSC), a non-Gaussian covariance term that is sensitive to fluctuations on…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-23 S. Gouyou Beauchamps , F. Lacasa , I. Tutusaus , M. Aubert , P. Baratta , A. Gorce , Z. Sakr

Accurate photometric redshift estimation is critical for observational cosmology, especially in large-scale surveys where spectroscopic measurements are impractical. Traditional approaches include template fitting and machine learning, each…

Instrumentation and Methods for Astrophysics · Physics 2026-04-15 Jonas Chris Ferrao , Dickson Dias , Pranav Naik , Glory D'Cruz , Anish Naik , Siya Khandeparkar , Manisha Gokuldas Fal Dessai

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

Galaxy morphologies provide valuable insights into their formation processes, tracing the spatial distribution of ongoing star formation and encoding signatures of dynamical interactions. While such information has been extensively…

The distinction between stars and galaxies is a fundamental problem in the field of celestial classification. This issue has become challenging for these ongoing and upcoming digital surveys, which will produce terabytes and even petabytes…

Instrumentation and Methods for Astrophysics · Physics 2026-04-14 Zhuoming Han , Tianmeng Zhang , Chao Liu , Chenxiaoji Ling

We forecast astrophysical and cosmological parameter constraints from synergies between 21 cm intensity mapping and wide field optical galaxy surveys (both spectroscopic and photometric) over $z \sim 0-3$. We focus on the following survey…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-27 Hamsa Padmanabhan , Alexandre Refregier , Adam Amara

We present a new non-parametric method to quantify morphologies of galaxies based on a particular family of learning machines called support vector machines. The method, that can be seen as a generalization of the classical CAS…

Astrophysics · Physics 2009-11-13 M. Huertas-Company , D. Rouan , L. Tasca , G. Soucail , O. Le Fevre

We perform a rigorous cosmology analysis on simulated type Ia supernovae (SN~Ia) and evaluate the improvement from including photometric host-galaxy redshifts compared to using only the "zspec" subset with spectroscopic redshifts from the…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-08 Ayan Mitra , Richard Kessler , Surhud More , Renee Hlozek , The LSST Dark Energy Science Collaboration

We present an extension of the multi-band galaxy fitting method scarlet which allows the joint modeling of astronomical images from different instruments, by performing simultaneous resampling and convolution. We introduce a fast and…

Instrumentation and Methods for Astrophysics · Physics 2021-07-16 Rémy Joseph , Peter Melchior , Fred Moolekamp

We present an extended morphometric system to automatically classify galaxies from astronomical images. The new system includes the original and modified versions of the CASGM coefficients (Concentration $C_1$, Asymmetry $A_3$, and…

Astrophysics of Galaxies · Physics 2015-09-21 Fabricio Ferrari , Reinaldo Ramos de Carvalho , Marina Trevisan

Next generation observatories will enable us to study the first billion years of our Universe in unprecedented detail. Foremost among these are 21-cm interferometry with the HERA and the SKA, and high-$z$ galaxy observations with the James…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Jaehong Park , Nicolas Gillet , Andrei Mesinger , Bradley Greig

We present improved methods for using stars found in astronomical exposures to calibrate both star and galaxy colors as well as to adjust the instrument flat field. By developing a spectroscopic model for the SDSS stellar locus in…

We describe a simple and fast method to correct ellipticity measurements of galaxies from the distortion by the instrumental and atmospheric point spread function (PSF), in view of weak lensing shear measurements. The method performs a…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-01 M. Tewes , N. Cantale , F. Courbin , T. D. Kitching , G. Meylan

The advent of the James Webb Space Telescope (JWST) signals a new era in exploring galaxies in the high-$z$ universe. Current and upcoming JWST imaging will potentially detect galaxies out to $z \sim 20$, creating a new urgency in the quest…

The New Vacuum Solar Telescope (NVST) has been releasing its novel winged Ha data (WHD) since April 2021, namely the Ha imaging spectroscopic data. Compared with the prior released version, the new data are further co-aligned among the…

Solar and Stellar Astrophysics · Physics 2022-06-01 Yun-Fang Cai , Xu Yang , Yong-Yuang Xiang , Xiao-Li Yan , Zhen-Yu Jin , Hui Liu , Kai-Fan Ji

Accurate redshift estimates are a vital component in understanding galaxy evolution and precision cosmology. In this paper, we explore approaches to increase the applicability of machine learning models for photometric redshift estimation…

Instrumentation and Methods for Astrophysics · Physics 2026-01-27 Jonathan Soriano , Tuan Do , Srinath Saikrishnan , Vikram Seenivasan , Bernie Boscoe , Jack Singal , Evan Jones

The next generation of imaging surveys, including the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), Euclid, and the Nancy Grace Roman Space Telescope, will place unprecedented constraints on cosmology using weak…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-08 Andy Park , Xiangchong Li , Rachel Mandelbaum , Matthew Becker

We present an application of unsupervised machine learning - the self-organised map (SOM) - as a tool for visualising, exploring and mining the catalogues of large astronomical surveys. Self-organisation culminates in a low-resolution…

Instrumentation and Methods for Astrophysics · Physics 2015-05-30 James E. Geach

The Chinese Space Station Telescope (CSST) spectroscopic survey aims to deliver high-quality low-resolution ($R > 200$) slitless spectra for hundreds of millions of targets down to a limiting magnitude of about 21 mag, distributed within a…

Instrumentation and Methods for Astrophysics · Physics 2021-05-05 Haibo Yuan , Dingshan Deng , Yang Sun

This paper aims at providing a comprehensive framework to generate an astrophysical scene and to simulate realistic hyperspectral and multispectral data acquired by two JWST instruments, namely NIRCam Imager and NIRSpec IFU. We want to show…

Instrumentation and Methods for Astrophysics · Physics 2020-06-24 Claire Guilloteau , Thomas Oberlin , Olivier Berné , Nicolas Dobigeon