Ya‐Wen Tang
A5106417970- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Laser-Plasma Interactions and Diagnostics
- Laser Design and Applications
- Galaxies: Formation, Evolution, Phenomena
- Laser-Matter Interactions and Applications
- Spectroscopy and Laser Applications
- Astrophysical Phenomena and Observations
- Laser-induced spectroscopy and plasma
- Advanced Fiber Laser Technologies
- Solar and Space Plasma Dynamics
- Astronomy and Astrophysical Research
- Laser Material Processing Techniques
- Solid State Laser Technologies
- Ionosphere and magnetosphere dynamics
- Atomic and Molecular Physics
- Astronomical Observations and Instrumentation
- Planetary Science and Exploration
- Pulsed Power Technology Applications
- Advanced Combustion Engine Technologies
- Magnetic and Electromagnetic Effects
- Orbital Angular Momentum in Optics
Institute of Astronomy and Astrophysics, Academia Sinica
2015-2024
Central Laser Facility
2019
Rutherford Appleton Laboratory
2007-2019
Centro Laser
2019
Academia Sinica
2008-2018
Optical Sciences (United States)
2018
University of York
2018
Imperial College London
2018
Tata Institute of Fundamental Research
2018
Raja Ramanna Centre for Advanced Technology
2018
The circumstellar disk of AB Aurigae has garnered strong attention owing to the apparent existence spirals at a relatively young stage and also asymmetric traced in thermal dust emission. However, physical conditions are still not well understood. origin emission is unclear. We observed 230 GHz (1.3 mm) both continuum spectral line ^12CO J=2-1 with IRAM 30-m, Plateau de Bure interferometer, Submillimeter Array sample all spatial scales from 0.37" about 50". To combine data obtained these...
Massive stars ($M > 8$ \msun) typically form in parsec-scale molecular clumps that collapse and fragment, leading to the birth of a cluster stellar objects. We investigate role magnetic fields this process through dust polarization at 870 $\mu$m obtained with Submillimeter Array (SMA). The SMA observations reveal scales $\lsim$ 0.1 pc. pattern these objects ranges from ordered hour-glass configurations more chaotic distributions. By comparing data single dish parsec scales, we found dense...
We present the first results from B-fields In STar-forming Region Observations (BISTRO) survey, using Sub-millimetre Common-User Bolometer Array 2 (SCUBA-2) camera, with its associated polarimeter (POL-2), on James Clerk Maxwell Telescope (JCMT) in Hawaii. discuss survey's aims and objectives. describe rationale behind questions which survey will aim to answer. The most important of these is role magnetic fields star formation process scale individual filaments cores dense regions. data...
A full understanding of high-mass star formation requires the study one most elusive components energy balance in interstellar medium: magnetic fields. We report ALMA 1.2 mm, high-resolution (700 au) dust polarization and molecular line observations rotating hot core embedded star-forming region IRAS 18089-1732. The continuum emission field morphology present spiral-like features resembling a whirlpool. velocity traced by H13CO+ (J=3-2) transition reveals complex structure with spiral...
We report our observational results of 870 μm continuum emission and its linear polarization in the massive star formation site W51 e2/e8. Inferred from maps, magnetic field plane sky (B⊥) is traced with an angular resolution 07 Submillimeter Array. Whereas previous BIMA observations 3'' (0.1 pc) showed a uniform B field, revealed B⊥ morphology hourglass-like collapsing core near ultracompact H ii region e2 also possibly e8. The decrease peak seen at lower apparently due to more complex...
The aim of this project is to establish a 10 PW facility on the Vulcan laser system capable being focussed intensities at least 1023 Wcm−2 and integrate into flexible unique user This paper will present progress made in Phase one developing 10PW Front End as well concept for new facility. be configured way maximise scientific opportunities presented through combination with existing capabilities already established Vulcan. ground breaking development open up range opportunities.
We perform imaging and analyses of SMA 1.3 mm continuum, C18O (2-1) 12CO line data 17 Class 0 0/I protostars to study their gas kinematics on a 1,000-AU scale. Continuum emission are detected toward all the sample sources show central primary components with sizes ~600-1,500 AU associated protostars. The velocity gradients in have wide ranges orientations from parallel perpendicular outflows, magnitudes ~1 ~530 km/s/pc. construct simple kinematic model reproduce observed gradients, estimate...
Context. Planet formation is expected to take place in the first million years of a planetary system through various processes, which remain be tested observations. Aims. With recent discovery, using ALMA, two gaseous spiral arms inside 120 au cavity and connected dusty spirals, famous protoplanetary disk around AB Aurigae presents strong incentive for investigating mechanisms that lead giant planet formation. A candidate protoplanet located arm has already been claimed an earlier study...
Studying the earliest stages in birth of stars is crucial for understanding how they form. Brown dwarfs with masses between that and planets are not massive enough to maintain stable hydrogen-burning fusion reactions during most their lifetime. Their origins subject much debate recent literature because far below typical mass where core collapse expected occur. We present first confirmed evidence brown undergo a phase molecular outflow young stars. Using Submillimeter Array, we have obtained...
We present high-angular-resolution observations of the massive star forming core DR21(OH) at 880 mum using Submillimeter Array (SMA). The dense exhibits an overall velocity gradient in a Keplerian-like pattern, which breaks center where SMA 6 and 7 are located. dust polarization shows complex magnetic field, compatible with toroidal configuration. This is contrast large, parsec-scale filament that surrounds core, there smooth field. total field strengths 0.9 2.1 mG, respectively. found...
We report the results of ALMA observations a protoplanetary disk surrounding Herbig Ae star AB Aurigae. obtained high-resolution (0.1"; 14 au) images in $^{12}$CO (J=2-1) emission and dust continuum at wavelength 1.3 mm. The is detected center ring with radius $\sim$ 120 au. CO dominated by two prominent spirals within ring. These are trailing appear to be about 4 times brighter than their medium. Their kinematics consistent Keplerian rotation an inclination 23 degree. apparent...
Abstract Most protostars have luminosities that are fainter than expected from steady accretion over the protostellar lifetime. The solution to this problem may lie in episodic mass accretion—prolonged periods of very low punctuated by short bursts rapid accretion. However, timescale and amplitude for variability at phase is almost entirely unconstrained. In A James Clerk Maxwell Telescope/SCUBA-2 Transient Survey Protostars Nearby Star-forming Regions, we monitoring monthly with SCUBA-2...
We present Atacama Large Millimeter Array (ALMA) observations at an angular resolution of 0.1-0.2" the disk surrounding young Herbig Ae star MWC 758. The data consist images dust continuum emission recorded 0.88 millimeter, as well 13CO and C18O J = 3-2 lines. is characterized by a large cavity roughly 40 au in radius which might contain mildly inner warped disk. outer features two bright clumps radii about 47 82 that azimuthal extensions form double-ring structure. comparison with radiative...
Context . Studying molecular species in protoplanetary disks is very useful to characterize the properties of these objects, which are site planet formation. Aims We attempt constrain chemistry S-bearing molecules cold parts circumstellar disk GG Tau A. Methods searched for H 2 S, CS, SO, and SO dense around A with NOrthem Extended Millimeter Array (NOEMA) interferometer. analyzed our data using radiative transfer code DiskFit three-phase chemical model Nautilus. Results detected S emission...
Abstract We present 850 μ m imaging polarimetry data of the ρ Oph-A core taken with Submillimeter Common-User Bolometer Array-2 (SCUBA-2) and its polarimeter (POL-2) as part our ongoing survey project, <?CDATA ${\boldsymbol{B}}$?> -fields In STar forming RegiOns (BISTRO). The polarization vectors are used to identify orientation magnetic field projected on plane sky at a resolution 0.01 pc. 10 subregions distinct fractions angles in 0.2 pc core; some them can be coherent structure Oph...
Abstract We present the B -fields mapped in IRDC G34.43+0.24 using 850 μ m polarized dust emission observed with POL-2 instrument at James Clerk Maxwell telescope. examine magnetic field geometries and strengths northern, central, southern regions of filament. The overall geometry is ordered aligned closely perpendicular to filament’s main axis, particularly containing central clumps MM1 MM2, whereas MM3 north has orientations its major axis. are uniform large (POL-2 14″ SHARP 10″) small...
Abstract We report 850 μ m continuum polarization observations toward the filamentary high-mass star-forming region NGC 2264, taken as part of B -fields In STar forming Regions Observations large program on James Clerk Maxwell Telescope. These data reveal a well-structured nonuniform magnetic field in 2264C and 2264D regions with prevailing orientation around 30° from north to east. Field strength estimates virial analysis major clumps indicate that is globally dominated by gravity, while...
Abstract Recent high-resolution observations at millimeter (mm) and submillimeter wavelengths reveal a diverse spatial distribution for subparsec-scale dense cores within star-forming regions, ranging from clustered to aligned arrangements. To address the increasing volume of observational simulation data, we introduce “alignment parameters” as quantitative reproducible method automatically assess core alignment. We first demonstrate effectiveness these parameters by applying them artificial...
Abstract Late infall events challenge the traditional view that planet formation occurs without external influence. Here we present deep Atacama Large Millimeter/submillimeter Array 12 CO J = 2–1 and SO N 5 6 –4 observations toward AB Aurigae (AB Aur), a Class II disk system with strong signs of gravitational instability ongoing formation. By applying Keplerian anti-Keplerian masks, separate disk-like non-disk-like motions CO, considering two outputs as “disk” “exo-disk” (out disk) emission...
The physical mechanisms behind the fragmentation of high-mass dense clumps into compact star-forming cores and properties these are fundamental topics that heavily investigated in current astrophysical research. ALMAGAL survey provides opportunity to study this process at an unprecedented level detail statistical significance, featuring high-angular resolution $1.38$ mm ALMA observations $1013$ massive various Galactic locations. These cover a wide range distances (∼2-8,kpc), masses M_ ⊙ ),...
A large fraction of stars form in clusters containing high-mass stars, which subsequently influences the local and galaxy-wide environment. Fundamental questions about physics responsible for fragmenting molecular parsec-scale clumps into cores a few thousand astronomical units (au) are still open, that only statistically significant investigation with ALMA is able to address; instance: identification dominant agents determine core demographics, mass, spatial distribution as function...
We report high angular resolution (3'') Submillimeter Array (SMA) observations of the molecular cloud associated with Ultracompact H ii region G5.89 − 0.39. Imaged dust continuum emission at 870 μm reveals significant linear polarization. The position angles (P.A.s) polarization vary enormously but smoothly in a 2 × 104 AU. Based on distribution P.A.s and structures, polarized can be separated roughly into two components. component "x" is well-defined ridge μm, likely tracing compressed B...