Manwei Chan
A5090484571- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Galaxies: Formation, Evolution, Phenomena
- Pulsars and Gravitational Waves Research
- Geophysics and Gravity Measurements
- Superconducting and THz Device Technology
- Astronomy and Astrophysical Research
- Statistical and numerical algorithms
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Space Satellite Systems and Control
- Astrophysics and Cosmic Phenomena
- Planetary Science and Exploration
- Optical Network Technologies
- Spacecraft Dynamics and Control
- Systems Engineering Methodologies and Applications
- Stellar, planetary, and galactic studies
- Ionosphere and magnetosphere dynamics
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Nonlinear Photonic Systems
- Semiconductor Lasers and Optical Devices
- Modular Robots and Swarm Intelligence
- Advanced Fiber Laser Technologies
- Solar and Space Plasma Dynamics
Johns Hopkins University
2014-2022
Fukuoka University
2022
American Institute of Aeronautics and Astronautics
2020
Massachusetts Institute of Technology
2020
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 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 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...
Abstract The Cosmology Large Angular Scale Surveyor (CLASS) is a telescope array that observes the cosmic microwave background (CMB) over 75% of sky from Atacama Desert, Chile, at frequency bands centered near 40, 90, 150, and 220 GHz. CLASS measures large angular scale (1° ≲ θ 90°) CMB polarization to constrain tensor-to-scalar ratio r ∼ 0.01 level optical depth last scattering sample variance limit. This paper presents characterization 40 GHz during its first observation era, 2016...
The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in Atacama Desert Chile, it will observe over 65% sky 38, 93, 148, and 217 GHz. In this paper we discuss design, construction, characterization CLASS 38 GHz detector focal plane, first ever Q-band bolometric polarimeter array.
The current and future cosmic microwave background (CMB) experiments fielding kilo-pixel arrays of transition-edge sensor (TES) bolometers require accurate robust gain calibration methods. We simplify refactor the standard TES model to directly relate detector responsivity optical time constant measured $I$ applied bias $I_{\mathrm{b}}$. method developed for Cosmology Large Angular Scale Surveyor (CLASS) bolometer relies on versus voltage ($I$-$V$) measurements acquired daily prior CMB...
The search for inflationary primordial gravitational waves and the measurement of optical depth to reionization, both through their imprint on large angular scale correlations in polarization cosmic microwave background (CMB), has created need high sensitivity measurements across fractions sky at millimeter wavelengths. These are subject instrumental atmospheric 1=f noise, which motivated development modulators facilitate rejection these systematic effects. Variable-delay (VPMs) used...
The Cosmology Large Angular Scale Surveyor (CLASS) is a four-telescope array observing the largest angular scales ($2 \lesssim \ell 200$) of cosmic microwave background (CMB) polarization. These encode information about reionization and inflation during early universe. instrument stability necessary to observe these from ground achieved through use variable-delay polarization modulator (VPM) as first optical element in each CLASS telescopes. Here we develop demodulation scheme used extract...
The Cosmology Large Angular Scale Surveyor (CLASS) is mapping the polarization of Cosmic Microwave Background (CMB) at large angular scales ($2<\ell\lesssim200$) in search a primordial gravitational wave B-mode signal down to tensor-to-scalar ratio $r \approx 0.01$. same data set will provide near sample-variance-limited measurement optical depth reionization. Between June 2016 and March 2018, CLASS completed largest ground-based Q-band CMB survey date, covering over 31 000~square-degrees...
Abstract We report measurements of circular polarization from the first two years observation with 40 GHz polarimeter Cosmology Large Angular Scale Surveyor (CLASS). CLASS is conducting a multi-frequency survey covering 75% sky Atacama Desert designed to measure cosmic microwave background (CMB) linear E and B on angular scales 1° ≲ θ ≤ 90°, corresponding multipole range 2 ℓ 200. The modulation technology enabling at largest ground, Variable-delay Polarization Modulator, uniquely provide...
Abstract Using the Cosmology Large Angular Scale Surveyor, we measure disk-averaged absolute Venus brightness temperature to be 432.3 ± 2.8 K and 355.6 1.3 in Q W frequency bands centered at 38.8 93.7 GHz, respectively. At both bands, these are most precise measurements date. Furthermore, observe no phase dependence of measured either band. Our consistent with a CO 2 -dominant atmospheric model that includes trace amounts additional absorbers like SO H 4 .
NASA is interested in characterizing and robotically exploring the lunar permanently shadowed regions (PSRs) advance of Artemis crewed landings. The challenging terrain these means a lander would only be able to access rim PSR, limiting line-of-sight communication sensing into PSR. Autonomously deployed tower infrastructures could provide valuable lines sight around PSRs. has developed deployable composite booms for use microgravity, we propose an extension those capabilities by deploying...
The Earth's magnetic field induces Zeeman splitting of the dipole transitions molecular oxygen in atmosphere, which produces polarized emission millimeter-wave regime. This is primarily circularly and manifests as a foreground with dipole-shaped sky pattern for polarization-sensitive ground-based cosmic microwave background experiments, such Cosmology Large Angular Scale Surveyor (CLASS), capable measuring large angular scale circular polarization. Using atmospheric theory radiative transfer...
The Cosmology Large Angular Scale Surveyor (CLASS) is an array of polarization-sensitive millimeter wave telescopes that observes ~70% the sky at frequency bands centered near 40GHz, 90GHz, 150GHz, and 220GHz from Atacama desert northern Chile. Here, we describe architecture software used to control telescopes, acquire data various instruments, schedule observations, monitor status instruments create archival packages, transfer packages North America for analysis. computer network CLASS...
We describe the instrument architecture of CLASS instrument, a ground-based cosmic microwave background (CMB) polarimeter that will measure large-scale polarization CMB in several frequency bands to search for evidence inflation.
The development of a Rendezvous and Proximity Operations (RPO) guidance algorithm for approaching uncooperative tumbling satellites has multiple purposes including on-orbit satellite servicing, space debris removal, asteroid mining, assembly. This paper develops within the framework but is extendable to other mission scenarios. author tests in an RPO simulation with near Geostationary Orbit (GEO) starting at relative distance 50 m ending 5 m. Due low Technology Readiness Level (TRL)...
Soliton transmission through cascaded fibre amplifiers has attracted widespread attention recently. Two schemes, namely, "average soliton method" and "preemphasis method", were proposed to propagate solitons such a link. We compare the two methods by studying propagation behavior along number of optical amplifier stages. Numerical simulation shown that preemphasis method works reasonably well only under certain conditions require relatively small spacings. If these are violated, leads...