Publications by Jiaxi Yu | EPFL Graph Search

Related publications (26)

A Brief History of Cosmology with Galaxy-Halo Relation and Systematics in Redshift Surveys

This dissertation traces the evolution of cosmology from its foundational theories to the forefront of modern observational studies, with a particular focus on the role of large-scale structure (LSS) probes. It begins with the establishment of General Rela ...

EPFL2024

The completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: cosmological implications from multitracer BAO analysis with galaxies and voids

Jean-Paul Richard Kneib, Cheng Zhao, Huanyuan Shan, Jiaxi Yu, Daniel Felipe Forero Sanchez, Amélie Tamone, Andrei Variu

We construct cosmic void catalogues with the DIVE void finder upon SDSS BOSS DR12 and eBOSS DR16 galaxy samples with BAO reconstruction, and perform a joint BAO analysis using different types of galaxies and the corresponding voids. The BAO peak is evident ...

OXFORD UNIV PRESS2022

Mitigating imaging systematics for DESI 2024 emission Line Galaxies and beyond

Jiaxi Yu

Emission Line Galaxies (ELGs) are one of the main tracers that the Dark Energy Spectroscopic Instrument (DESI) uses to probe the universe. However, they are afflicted by strong spurious correlations between target density and observing conditions known as ...

IOP Publishing2025

Void Lensing in Cubic Galileon Gravity

Cheng Zhao, Huanyuan Shan, Jiaxi Yu, Qiao Wang

Weak-lensing studies via cosmic voids are a promising probe of modified gravity (MG). The excess surface mass density (ESD) is widely used as a lensing statistic in weak-lensing research. In this paper, we use the ray-tracing method to study the ESD around ...

IOP Publishing Ltd2023

Analytical and EZmock covariance validation for the DESI 2024 results

Jiaxi Yu, Daniel Felipe Forero Sanchez

The estimation of uncertainties in cosmological parameters is an important challenge in Large-Scale-Structure (LSS) analyses. For standard analyses such as Baryon Acoustic Oscillations (BAO) and Full-Shape two approaches are usually considered. First: anal ...

2025

Hod-dependent Systematics in Emission Line Galaxies for the Desi 2024 Bao Analysis

Jiaxi Yu, Antoine Philippe Jacques Rocher

The Dark Energy Spectroscopic Instrument (DESI) will provide precise measurements of Baryon Acoustic Oscillations (BAO) to constrain the expansion history of the Universe and set stringent constraints on dark energy. Therefore, precise control of the globa ...

IOP Publishing Ltd2025

Cosmological Fisher forecasts for next-generation spectroscopic surveys

Jean-Paul Richard Kneib, Cheng Zhao, Jiaxi Yu

Next-generation spectroscopic surveys such as the MegaMapper, MUltiplexed Survey Telescope (MUST), MaunaKea Spectroscopic Explorer (MSE), and WideField Spectroscopic Telescope (WST) are foreseen to increase the number of galaxy/quasar redshifts by an order ...

OXFORD UNIV PRESS2023

The construction of large-scale structure catalogs for the Dark Energy Spectroscopic Instrument

Jiaxi Yu

We present the technical details on how large-scale structure (LSS) catalogs are constructed from redshifts measured from spectra observed by the Dark Energy Spectroscopic Instrument (DESI). The LSS catalogs provide the information needed to determine the ...

IOP Publishing Ltd2025

The DESI One-Percent Survey: Constructing Galaxy-Halo Connections for ELGs and LRGs Using Auto and Cross Correlations

Jiaxi Yu

In the current Dark Energy Spectroscopic Instrument (DESI) survey, emission line galaxies (ELGs) and luminous red galaxies (LRGs) are essential for mapping the dark matter distribution at < N(M)>. We measure the auto and cross correlation functions of ELGs ...

IOP Publishing Ltd2023

ELG spectroscopic systematics analysis of the DESI Data Release 1

Jean-Paul Richard Kneib, Jiaxi Yu, Daniel Felipe Forero Sanchez, Antoine Philippe Jacques Rocher

Dark Energy Spectroscopic Instrument (DESI) uses more than 2.4 million Emission Line Galaxies (ELGs) for 3D large-scale structure (LSS) analyses in its Data Release 1 (DR1). Such large statistics enable thorough research on systematic uncertainties. In thi ...

IOP Publishing Ltd2025

Desi 2024 Vi: Cosmological Constraints From the Measurements of Baryon Acoustic Oscillations

Jiaxi Yu, Daniel Felipe Forero Sanchez, Antoine Philippe Jacques Rocher

We present cosmological results from the measurement of baryon acoustic oscillations (BAO) in galaxy, quasar and Lyman-alpha forest tracers from the first year of observations from the Dark Energy Spectroscopic Instrument (DESI), to be released in the DESI ...

IOP Publishing Ltd2025

Baryon acoustic oscillation theory and modelling systematics for the DESI 2024 results

Jiaxi Yu, Daniel Felipe Forero Sanchez

This paper provides a comprehensive overview of how fitting of baryon acoustic oscillations (BAO) is carried out within the upcoming Dark Energy Spectroscopic Instrument’s (DESI) 2024 results using its DR1 data set, and the associated systematic error budg ...

2024

Performance of the Quasar Spectral Templates for the Dark Energy Spectroscopic Instrument

Jiaxi Yu, Zheng Zheng

Millions of quasar spectra will be collected by the Dark Energy Spectroscopic Instrument (DESI), leading to a fourfold increase in the number of known quasars. High-accuracy quasar classification is essential to tighten constraints on cosmological paramete ...

IOP Publishing Ltd2023

Optimal reconstruction of baryon acoustic oscillations for DESI 2024

Jiaxi Yu

Baryon acoustic oscillations (BAO) provide a robust standard ruler to measure the expansion history of the Universe through galaxy clustering. Density-field reconstruction is now a widely adopted procedure for increasing the precision and accuracy of the B ...

2025

Model BOSS and eBOSS luminous red galaxies at 0.2 < z < 1.0 using SubHalo Abundance Matching with three parameters

Jean-Paul Richard Kneib, Cheng Zhao, Anand Stéphane Raichoor, Jiaxi Yu, Ginevra Favole

SubHalo Abundance Matching (SHAM) is an empirical method for constructing galaxy catalogues based on high-resolution N-body simulations. We apply SHAM on the UNIT simulation to simulate SDSS BOSS/eBOSS luminous red galaxies (LRGs) within a wide redshift ra ...

OXFORD UNIV PRESS2022

Fiducial-cosmology-dependent systematics for the DESI 2024 BAO analysis

Jiaxi Yu, Antoine Philippe Jacques Rocher

When measuring the Baryon Acoustic Oscillations (BAO) scale from galaxy surveys, one typically assumes a fiducial cosmology when converting redshift measurements into comoving distances and also when defining input parameters for the reconstruction algorit ...

IOP Publishing Ltd2025

The DESI one-per cent survey: exploring the halo occupation distribution of luminous red galaxies and quasi-stellar objects with ABACUSSUMMIT

Jiaxi Yu, Zheng Zheng, Antoine Philippe Jacques Rocher

We present the first comprehensive halo occupation distribution (HOD) analysis of the Dark Energy Spectroscopic Instrument (DESI) One-Percent Survey luminous red galaxy (LRG) and Quasi Stellar Object (QSO) samples. We constrain the HOD of each sample and t ...

2024

HOD-dependent systematics for luminous red galaxies in the DESI 2024 BAO analysis

Jiaxi Yu, Antoine Philippe Jacques Rocher

In this paper, we present the estimation of systematics related to the halo occupation distribution (HOD) modeling in the baryon acoustic oscillations (BAO) distance measurement of the Dark Energy Spectroscopic Instrument (DESI) 2024 analysis. This paper f ...

IOP Publishing Ltd2025

Impact and mitigation of spectroscopic systematics on DESI DR1 clustering measurements

Jiaxi Yu

The large scale structure catalogs within DESI Data Release 1 (DR1) use nearly 6 million galaxies and quasars as tracers of the large-scale structure of the universe to measure the expansion history with baryon acoustic oscillations and the growth of struc ...

IOP Publishing Ltd2025

Overview of the Fiber System for the Dark Energy Spectroscopic Instrument

Jiaxi Yu

The Dark Energy Spectroscopic Instrument (DESI) is a revolutionary instrument designed for precise measurements of cosmic distances and the investigation of dark energy. DESI utilizes 5000 optical fibers to simultaneously measure the spectra of distant obj ...

2024