Yutong Duan
A5113923184- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Scientific Research and Discoveries
- Dark Matter and Cosmic Phenomena
- Structural Load-Bearing Analysis
- Computational Physics and Python Applications
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Retinal and Optic Conditions
- Retinal Imaging and Analysis
- Structural Behavior of Reinforced Concrete
- Retinal Diseases and Treatments
- CCD and CMOS Imaging Sensors
- Astrophysics and Star Formation Studies
- Structural Analysis and Optimization
- Thin-Film Transistor Technologies
- Relativity and Gravitational Theory
- Advanced SAR Imaging Techniques
- Text and Document Classification Technologies
- Silicon Nanostructures and Photoluminescence
- Superconducting and THz Device Technology
Lanzhou Jiaotong University
2023-2024
Taiyuan University of Technology
2022-2023
Boston University
2018-2022
The Ohio State University
2022
Zhuhai Institute of Advanced Technology
2021
Chinese Academy of Sciences
2021
Lawrence Berkeley National Laboratory
2018-2020
Abstract The DESI Legacy Imaging Surveys ( http://legacysurvey.org/ ) are a combination of three public projects (the Dark Energy Camera Survey, the Beijing–Arizona Sky and Mayall z -band Survey) that will jointly image ≈14,000 deg 2 extragalactic sky visible from northern hemisphere in optical bands g , r using telescopes at Kitt Peak National Observatory Cerro Tololo Inter-American Observatory. combined survey footprint is split into two contiguous areas by Galactic plane. imaging...
The Dark Energy Spectroscopic Instrument (DESI) has embarked on an ambitious five-year survey to explore the nature of dark energy with spectroscopy 40 million galaxies and quasars. DESI will determine precise redshifts employ Baryon Acoustic Oscillation method measure distances from nearby universe z > 3.5, as well growth structure probe potential modifications general relativity. In this paper we describe significant instrumentation developed for survey. new includes a wide-field, 3.2-deg...
Abstract A system of 5020 robotic fiber positioners was installed in 2019 on the Mayall Telescope, at Kitt Peak National Observatory. The robots automatically retarget their optical fibers every 10–20 minutes, each to a precision several microns, with reconfiguration time fewer than 2 minutes. Over next 5 yr, they will enable newly constructed Dark Energy Spectroscopic Instrument (DESI) measure spectra 35 million galaxies and quasars. DESI produce largest 3D map universe date expansion...
We present measurements of the redshift-dependent clustering a DESI-like luminous red galaxy (LRG) sample selected from Legacy Survey imaging dataset, and use halo occupation distribution (HOD) framework to fit signal. The photometric LRG in this study contains 2.7 million objects over redshift range $0.4 < z 0.9$ 5655 deg$^2$. have developed new (photo-$z$) estimates using DECam WISE photometry, with $\sigma_{\mathrm{NMAD}} = 0.02$ precision for LRGs. compute projected correlation function...
The DESI survey will observe more than 8 million candidate luminous red galaxies (LRGs) in the redshift range $0.3<z<1.0$. Here we present a preliminary version of LRG target selection developed using Legacy Surveys Data Release $g$, $r$, $z$ and $W1$ photometry. This yields sample with uniform surface density ${\sim}\,600$ deg$^{-2}$and very low predicted stellar contamination failure rates. During Survey Validation, updated versions this be tested optimized.
Inflation may provide unique insight into the physics at highest available energy scales that cannot be replicated in any realistic terrestrial experiment. Features primordial power spectrum are generically predicted a wide class of models inflation and its alternatives, observationally one most overlooked channels for finding evidence non-minimal inflationary models. Constraints from observations cosmic microwave background cover widest range feature frequencies, but sensitive constraints...
Abstract The DESI survey will measure large-scale structure using quasars as direct tracers of dark matter in the redshift range 0.9 < z 2.1 and quasar Ly α forests at > 2.1. We present two methods to select candidate for based on imaging three optical ( g , r ) infrared W 1, 2) bands. first method uses traditional color cuts second utilizes a machine-learning algorithm.
The DESI Milky Way Survey (MWS) will observe $\ge$8 million stars between $16 < r 19$ mag, supplemented by observations of brighter targets under poor observing conditions. survey permit an accurate determination stellar kinematics and population gradients; characterize diffuse substructure in the thick disk halo; enable discovery extremely metal-poor other rare types; improve constraints on Galaxy's 3D dark matter distribution from halo star kinematics. MWS also a detailed characterization...
The hot dense environment of the early universe is known to have produced large numbers baryons, photons, and neutrinos. These extreme conditions may also other long-lived species, including new light particles (such as axions or sterile neutrinos) gravitational waves. effects any such relics can be observed through their unique imprint in cosmic microwave background (CMB), large-scale structure, primordial element abundances, are important determining initial universe. We argue that future...
Abstract DESI will precisely constrain cosmic expansion and the growth of structure by collecting ∼35 million redshifts across ∼80% history one third sky to study Baryon Acoustic Oscillations (BAO) Redshift Space Distortions (RSD). We present a preliminary target selection for an Emission Line Galaxy (ELG) sample, which comprise about half all tracers. The consists g -band magnitude cut ( − r ) versus z color box, we validate using HSC/PDR2 photometric DEEP2 spectroscopy. ELG density should...
The statistical power of Lyman-α forest Baryon Acoustic Oscillation (BAO) measurements is set to increase significantly in the coming years as new instruments such Dark Energy Spectroscopic Instrument deliver progressively more constraining data. Generating mock datasets for will be important validating analysis pipelines and evaluating effects systematics. With studies mind, we present LyaCoLoRe: a package producing synthetic survey BAO analyses. LyaCoLoRe transforms initial Gaussian random...
The Dark Energy Spectroscopic Instrument (DESI) has embarked on an ambitious five-year survey to explore the nature of dark energy with spectroscopy 40 million galaxies and quasars. DESI will determine precise redshifts employ Baryon Acoustic Oscillation method measure distances from nearby universe z > 3.5, as well growth structure probe potential modifications general relativity. In this paper we describe significant instrumentation developed for survey. new includes a wide-field,...
The expansion of the Universe is understood to have accelerated during two epochs: in its very first moments a period Inflation and much more recently, at $z < 1$, when Dark Energy hypothesized drive cosmic acceleration. undiscovered mechanisms behind these epochs represent some most important open problems fundamental physics. large cosmological volume $2 z 5$, together with ability efficiently target high-$z$ galaxies known techniques, enables gains study Energy. A future spectroscopic...
The risk of fatigue failure welded hollow spherical joints (WHSJs) under alternating loads increases due to the inherent defects, disrepair, and demand for tonnage upgrades, suspension cranes. finite element analysis results revealed that ranking stress concentration factor at WHSJ was as follows: weld toe in steel tube tube–ball connection > tube–endplate sphere plate weld. Moreover, peak tube–sphere reduced by 32.93% after CFRP bonding reinforcement, which beneficial improving...
The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of universe using baryon acoustic oscillations technique. spectra 35 million galaxies and quasars over 14,000 square degrees will be measured during a 5-year survey. A new prime focus corrector for Mayall telescope at Kitt Peak National Observatory deliver light 5,000 individually targeted fiber-fed robotic positioners. fibers in turn feed ten broadband multi-object spectrographs. We...
Abstract The Dark Energy Spectroscopic Instrument (DESI) will execute a nearly magnitude-limited survey of low redshift galaxies (0.05 ≤ z 0.4, median ≈ 0.2). Clustering analyses this Bright Galaxy Survey (BGS) yield the most precise measurements to date baryon acoustic oscillations and redshift-space distortions at redshift. DESI BGS comprise two target classes: (i) BRIGHT ( r < 19.5 mag), (ii) FAINT (19.5 20 mag). Here we present summary star-galaxy separation, different photometric...
In preparation for the Dark Energy Spectroscopic Instrument (DESI), a new top end was installed on Mayall 4-meter telescope at Kitt Peak National Observatory. The refurbished and DESI instrument were successfully commissioned sky between 2019 October 2020 March. Here we describe pointing, tracking imaging performance of equipped with its prime focus corrector, as measured by six guider cameras sampling outer edge DESI's focal plane. Analyzing ~500,000 images acquired during commissioning,...
We utilise mock catalogues from high-accuracy cosmological $N$-body simulations to quantify shifts in the recovery of acoustic scale that could potentially result galaxy clustering bias. The relationship between galaxies and dark matter halos presents a complicated source systematic errors modern redshift surveys, particularly when aiming make measurements sub-percent precision. Apart scalar, linear bias parameter accounting for density contrast ratio tracers true distribution, other types...
The Dark Energy Spectroscopic Instrument (DESI) is a Stage IV ground-based dark energy experiment that will measure the expansion history of Universe using Baryon Acoustic Oscillation technique. spectra 35 million galaxies and quasars over 14000 square degrees be measured during life experiment. We describe installation major elements instrument at Mayall 4m telescope, completed in late 2019. previous prime focus corrector, spider vanes, upper rings were removed from Mayall's Serrurier truss...
The recently commissioned Dark Energy Spectroscopic Instrument (DESI) will measure the expansion history of universe using Baryon Acoustic Oscillation technique. spectra 35 million galaxies and quasars over 14000 sq deg be measured during life experiment. A new prime focus corrector for KPNO Mayall telescope delivers light to 5000 fiber optic positioners. fibers in turn feed ten broad-band spectrographs. We describe key aspects lessons learned from development, delivery installation system...
The recently commissioned Dark Energy Spectroscopic Instrument (DESI) will measure the expansion history of Universe using Baryon Acoustic Oscillation technique. spectra 35 million galaxies and quasars over 14,000 sq deg be measured during life experiment. A new prime focus corrector for KPNO Mayall telescope delivers light to 5,000 fiber optic positioners which in turn feed ten broad-band spectro- graphs. DESI focal plane subsystem contains guide cameras, enable alignment fibers with...
The recently commissioned Dark Energy Spectroscopic Instrument (DESI) will measure the expansion history of Universe using Baryon Acoustic Oscillation technique. spectra 35 million galaxies and quasars over 14000 sq deg be measured during life experiment. A new prime focus corrector for KPNO Mayall telescope delivers light to 5000 fiber optic positioners. fibers in turn feed ten broad-band spectrographs. We describe use a Faro Laser Tracker with custom hardware software tools alignment...