A5053554694- Radio Astronomy Observations and Technology
- Superconducting and THz Device Technology
- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Particle physics theoretical and experimental studies
- Astrophysics and Star Formation Studies
- High-Energy Particle Collisions Research
- Geophysics and Gravity Measurements
- Dark Matter and Cosmic Phenomena
- Quantum Chromodynamics and Particle Interactions
- Adaptive optics and wavefront sensing
- Precipitation Measurement and Analysis
- Electrical Contact Performance and Analysis
- Astronomical Observations and Instrumentation
- Software Engineering Research
- Physics of Superconductivity and Magnetism
- Antenna Design and Optimization
- Computational Physics and Python Applications
- Scientific Research and Discoveries
- Stellar, planetary, and galactic studies
- Parallel Computing and Optimization Techniques
- Vacuum and Plasma Arcs
- Pulsars and Gravitational Waves Research
Massachusetts Institute of Technology
2010-2025
University of Pennsylvania
2018-2024
Fuzhou University
2024
Jilin Province Development and Reform Commission
2024
Beijing Institute of Technology
2024
Johns Hopkins University
2014-2023
California University of Pennsylvania
2018-2022
Peking University
2015-2022
Southwest Jiaotong University
2021-2022
Kavli Institute for Particle Astrophysics and Cosmology
2020-2022
The imprint left on the cosmic microwave background (CMB) from CMB photons scattering off high-energy electrons in galaxies and clusters is known as Sunyaev-Zel'dovich (SZ) effect subject of these two papers Atacama Cosmology Telescope (ACT). ACT measurements combined with those Planck BOSS are shown to provide a rich picture electron gas thermodynamics galactic cluster medium. This can be used test improve cosmological simulations relevant for upcoming experiments.
The early dark energy (EDE) scenario aims to increase the value of Hubble constant (${H}_{0}$) inferred from cosmic microwave background (CMB) data over that found in standard cosmological model ($\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$), via introduction a new form density Universe. EDE component briefly accelerates expansion just prior recombination, which reduces physical size sound horizon imprinted CMB. Previous work has nonzero is not preferred by Planck CMB power spectrum alone,...
The Cosmology Large Angular Scale Surveyor (CLASS) is an experiment to measure the signature of a gravitationalwave background from inflation in polarization cosmic microwave (CMB). CLASS multi-frequency array four telescopes operating high-altitude site Atacama Desert Chile. will survey 70% sky frequency bands centered at 38, 93, 148, and 217 GHz, which are chosen straddle Galactic-foreground minimum while avoiding strong atmospheric emission lines. This broad coverage ensures that can...
The thermal and kinematic Sunyaev-Zel'dovich effects (tSZ, kSZ) probe the thermodynamic properties of circumgalactic intracluster medium (CGM ICM) galaxies, groups, clusters, since they are proportional, respectively, to integrated electron pressure momentum along line-of-sight. We present constraints on gas thermodynamics CMASS galaxies in Baryon Oscillation Spectroscopic Survey (BOSS) using new measurements kSZ tSZ signals obtained a companion paper. Combining measurements, we measure...
Optimal analyses of many signals in the cosmic microwave background (CMB) require map-level extraction individual components sky, rather than measurements at power spectrum level alone. To date, nearly all component separation CMB has been performed exclusively using satellite data. In this paper, we implement a method based on internal linear combination (ILC) approach which have designed to optimally account for anisotropic noise (in 2D Fourier domain) often found ground-based experiments....
This paper presents a maximum-likelihood algorithm for combining sky maps with disparate coverage, angular resolution and spatially varying anisotropic noise into single map of the sky. We use this to merge hundreds individual covering 2008-2018 ACT observing seasons, resulting in by far deepest released so far. also combine full Planck maps, that have best features both ACT: Planck's nearly white on intermediate large scales ACT's high-resolution sensitivity small scales. The cover over...
Abstract As the unique power entrance, pantograph–catenary electrical contact system maintains efficiency and reliability of transmission for high-speed train. Along with fast development railways all over world, some commercialized lines are built covering remote places under harsh environment, especially in China; these environmental elements including wind, sand, rain, thunder, ice snow need to be considered during design system. The includes pantograph, wire interface—pantograph slide....
Abstract Measurement of the largest angular scale ( ℓ < 30) features cosmic microwave background (CMB) polarization is a powerful way to constrain optical depth reionization and search for signature inflation through detection primordial B -modes. We present an analysis maps covering 73.6% sky made from 40 GHz channel Cosmology Large Angular Scale Surveyor (CLASS) 2016 August 2022 May. Taking advantage measurement stability enabled by front-end modulation excellent conditions Atacama...
Abstract This paper presents the design and deployment of Hydrogen Epoch Reionization Array (HERA) phase II system. HERA is designed as a staged experiment targeting 21 cm emission measurements Reionization. First results from I array are published early 2022, system nearing completion. We describe discuss progress on commissioning future upgrades. As designated Square Kilometre pathfinder instrument, we also show number “case studies” that investigate systematics seen while system, which...
Library-based record and replay tools aim to reproduce an application's execution by recording the results of selected functions in a log during returning from rather than executing functions. These must ensure that run is identical run. The challenge doing so only invocations function application should be recorded, side effects call can difficult, not calls replay, multithreading, presence tool may change behavior replay. problems have limited use such tools.R2 allows developers choose...
The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from in ation and the optical depth reionization through measurement of polarized cosmic microwave background (CMB) on largest angular scales. frequencies CLASS telescopes, one at 38 GHz, two 93 dichroic system 145/217 are chosen avoid spectral regions high atmospheric emission span minimum Galactic foregrounds: synchrotron lower dust higher frequencies....
The Simons Observatory (SO) will make precise temperature and polarization measurements of the cosmic microwave background (CMB) using a set telescopes which cover angular scales between 1 arcminute tens degrees, contain over 60,000 detectors, observe at frequencies 27 270 GHz. SO consist 6 m aperture telescope coupled to 30,000 transition-edge sensor bolometers along with three 42 cm refractive telescopes, an additional 30,000+ all be located in Atacama Desert altitude 5190 m. powerful...
The Cosmology Large Angular Scale Surveyor (CLASS) observes the polarized cosmic microwave background (CMB) over angular scales of 1$^\circ \lesssim \theta \leq$ 90$^\circ$ with aim characterizing primordial gravitational waves and reionization. We report on on-sky performance CLASS Q-band (40 GHz), W-band (90 dichroic G-band (150/220 GHz) receivers that have been operational at site in Atacama desert since June 2016, May 2018, September 2019, respectively. show noise-equivalent power...
In this work, composite materials with nonlinear conductivity are used to enable grading of the electric field distribution along polymeric outdoor insulators, particularly near high-voltage and ground terminals. A ZnO spherical microvaristor/carbon fiber (CF)/ silicone rubber (SR) is as material (FGM). Finite element method-based numerical simulations performed analyze distributions 220 500 kV insulators when type used. The fabricated based on results optical sensors measure their under...
An understanding of astrophysical feedback is important for constraining models galaxy formation and extracting cosmological information from current future weak lensing surveys. The thermal Sunyaev-Zel'dovich effect, quantified via the Compton-$y$ parameter, a powerful tool studying feedback, because it directly probes pressure hot, ionized gas residing in dark matter halos. Cross-correlations between galaxies maps obtained cosmic microwave background surveys are sensitive to redshift...
We present a $5.4\ensuremath{\sigma}$ detection of the pairwise kinematic Sunyaev-Zeldovich (kSZ) effect using Atacama Cosmology Telescope (ACT) and Planck CMB observations in combination with Luminous Red Galaxy samples from Sloan Digital Sky Survey (SDSS) DR15 catalog. Results are obtained three ACT maps: co-added 150 98 GHz maps, combining 2008--2018 (ACT DR5), which overlap SDSS over 3,700 sq. deg., component-separated map night-time only 2014--2015 DR4), overlapping 2,089 deg....
We measure the projected number density profiles of galaxies and splashback feature in clusters selected by Sunyaev--Zeldovich (SZ) effect from Advanced Atacama Cosmology Telescope (AdvACT) survey using observed Dark Energy Survey (DES). The radius for complete galaxy sample is consistent with theoretical measurements CDM-only simulations, located at $2.4^{+0.3}_{-0.4}$ Mpc $h^{-1}$. split based on color find significant differences profile shapes. Red those green valley show a...
Pantograph-catenary arc fault is the primary factor threatening stability of power transmission for high-speed railway. The motion characteristics pantograph-catenary under low air pressure and strong airflow significantly different from case atmospheric pressure. In this paper, an experimental platform was built to investigate root position-time column longitudinal drift height-time characteristic curves pressures velocites. Via analysing corresponding results, it can be found that there...
We introduce and validate a delensing framework for the Simons Observatory (SO), which will be used to improve constraints on inflationary gravitational waves by reducing lensing noise in measurements of $B$ modes CMB polarization. SO initially observe using three small aperture telescopes one large-aperture telescope. While polarization maps from small-aperture constrain waves, internal delens reconstructed data Since obtained dominated subdegree scales, constructs template lensing-induced...
Abstract We quantify the calibration requirements for systematic uncertainties next-generation ground-based observatories targeting large-angle B-mode polarization of Cosmic Microwave Background, with a focus on Simons Observatory (SO). explore gain calibration, bandpass center frequencies, and angles, including frequency variation latter across bandpass. find that frequencies must be known to percent levels or less avoid biases tensor-to-scalar ratio r order Δ r∼10 -3 , in line previous...
Observing in six frequency bands from 27 to 280 GHz over a large sky area, the Simons Observatory (SO) is poised address many questions Galactic astrophysics addition its principal cosmological goals. In this work, we provide quantitative forecasts on astrophysical parameters of interest for range science cases. We find that SO can: constrain spectrum polarized dust emission at level $\Delta\beta_d \lesssim 0.01$ and thus test models composition predict $\beta_d$ polarization differs...
Abstract The Simons Observatory (SO) is a cosmic microwave background survey experiment that includes small-aperture telescopes (SATs) observing from an altitude of 5200 m in the Atacama Desert Chile. SO SATs will cover six spectral bands between 27 and 280 GHz to search for primordial B-modes sensitivity σ ( r ) = 0.002, with quantified systematic errors well below this value. Each SAT self-contained cryogenic telescope 35° field view, 42 cm diameter optical aperture, 40 K half-wave plate,...
ABSTRACT Detection of the faint 21 cm line emission from Cosmic Dawn and Epoch Reionization will require not only exquisite control over instrumental calibration systematics to achieve necessary dynamic range observations but also validation analysis techniques demonstrate their statistical properties signal loss characteristics. A key ingredient in achieving this is ability perform high-fidelity simulations kinds data that are produced by large, many-element, radio interferometric arrays...