Tao-Chung Ching
A5066319916- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Galaxies: Formation, Evolution, Phenomena
- Molecular Spectroscopy and Structure
- Spectroscopy and Laser Applications
- Astrophysical Phenomena and Observations
- Advanced Chemical Physics Studies
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Superconducting Materials and Applications
- Astronomy and Astrophysical Research
- Atomic and Molecular Physics
- High-pressure geophysics and materials
- Spacecraft and Cryogenic Technologies
- Calibration and Measurement Techniques
- Geomagnetism and Paleomagnetism Studies
- Quantum, superfluid, helium dynamics
- Astrophysics and Cosmic Phenomena
- Ionosphere and magnetosphere dynamics
- Geophysics and Gravity Measurements
- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
National Radio Astronomy Observatory
2023-2024
National Astronomical Observatories
2017-2023
Chinese Academy of Sciences
2017-2023
Zhejiang Lab
2022-2023
Institute of Astronomy and Astrophysics, Academia Sinica
2021
University of Chinese Academy of Sciences
2021
National Tsing Hua University
2014-2019
Center for Astrophysics Harvard & Smithsonian
2014-2018
Abstract The Five-hundred-meter Aperture Spherical radio Telescope (FAST) has passed national acceptance and finished one pilot cycle of ‘Shared-Risk’ observations. It will start formal operation soon. In this context, paper describes testing results key fundamental parameters for FAST, aiming to provide basic support observation data reduction FAST scientific researchers. 19-beam receiver covering 1.05–1.45 GHz was utilized most these fluctuation in electronic gain the system is better than...
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...
Polarized emission is detected in two young nearly edge-on protostellar disks 343 GHz continuum at ~ 50 au (~ 0.12") resolution with Atacama Large Millimeter/submillimeter Array. One disk HH 212 (Class 0) and the other 111 (early Class I) system. Polarization fraction 1%. The has a radius of 60 au. mainly from nearside disk. polarization orientations are almost perpendicular to major axis, consistent either self-scattering or by grains aligned poloidal field around outer edge because optical...
Context. Molecular filaments and hubs have received special attention recently thanks to new studies showing their key role in star formation. While the (column) density velocity structures of both been carefully studied, magnetic field (B-field) properties yet be characterized. Consequently, B-fields formation evolution hub-filament systems is not well constrained. Aims. We aim understand B-field its interplay with turbulence gravity dynamical NGC 6334 filament network that harbours...
Abstract We report the results of new dust polarization a nearly edge-on disk in HH 212 protostellar system, obtained with Atacama Large Millimeter/submillimeter Array at ∼0.035″ (14 au) resolution continuum λ ∼ 878 μ m. Dust is detected within ∼44 au central source, where rotationally supported has formed. The polarized emission forms V-shaped structures opening to east, and probably west, arising from surfaces arm further away east which could be due potential spiral arms excited outer...
Magnetic fields play an important role in the evolution of interstellar medium and star formation. As only direct probe field strength, credible Zeeman measurements remain sparse due to lack suitable probes, particularly for cold, molecular gas. Here we report detection a magnetic $+$3.8 $\pm$ 0.3 $\mu$G through HI narrow self-absorption (HINSA) toward L1544, well-studied prototypical prestellar core early transition between starless protostellar phases characterized by high central number...
We present the results of dust emission polarization measurements Ophiuchus-B (Oph-B) carried out using Submillimetre Common-User Bolometer Array 2 (SCUBA-2) camera with its associated polarimeter (POL-2) on James Clerk Maxwell Telescope (JCMT) in Hawaii. This work is part B-fields In Star-forming Region Observations (BISTRO) survey initiated to understand role magnetic fields star formation for nearby star-forming molecular clouds. a first look at geometry and strength Oph-B. The field...
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 Submillimeter Array polarization observations of the CO J = 3–2 line toward NGC 1333 IRAS 4A. The Stokes I maps at an angular resolution ∼1″ reveal two bipolar outflows from binary sources kinematic features emission can be modeled by wind-driven ∼20° inclined plane sky. Close to protostars polarization, ∼2.″3, has a position angle approximately parallel magnetic field direction inferred dust polarizations. appears vary smoothly hourglass around core arc-like morphology...
We present new observations of the active star-formation region NGC 1333 in Perseus molecular cloud complex from James Clerk Maxwell Telescope B-Fields In Star-forming Region Observations (BISTRO) survey with POL-2 instrument. The BISTRO data cover entire (~1.5 pc x 2 pc) at 0.02 resolution and spatially resolve polarized emission individual filamentary structures for first time. inferred magnetic field structure is as a whole, each filament aligned different position angles relative to...
We report 850~$\mu$m dust polarization observations of a low-mass ($\sim$12 $M_{\odot}$) starless core in the $\rho$ Ophiuchus cloud, C, made with POL-2 instrument on James Clerk Maxwell Telescope (JCMT) as part JCMT B-fields In STar-forming Region Observations (BISTRO) survey. detect an ordered magnetic field projected plane sky core. The across $\sim$0.1~pc shows predominant northeast-southwest orientation centering between $\sim$40$^\circ$ to $\sim$100$^\circ$, indicating that is well...
Abstract Theoretical and numerical works indicate that a strong magnetic field should suppress fragmentation in dense cores. However, this has never been tested observationally relatively large sample of fragmenting massive Here, we use the polarization data obtained Submillimeter Array Legacy Survey Zhang et al. to build 18 cores where both properties are studied uniform way. We measured level, N mm , within view common all regions ∼0.15 pc, with mass sensitivity ∼0.5 M ☉ spatial resolution...
Abstract We present 850 μ m polarimetric observations toward the Serpens Main molecular cloud obtained using POL-2 polarimeter on James Clerk Maxwell Telescope as part of B-fields In STar-forming Region Observations survey. These probe magnetic field morphology about 6000 au scales, which consists cores and six filaments with different physical properties such density star formation activity. Using histogram relative orientation (HRO) technique, we find that fields are parallel to in...
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 The Five-hundred-meter Aperture Spherical radio Telescope (FAST) has been fully operational since 2020 January 11. We present a comprehensive analysis of the beam structure for each 19 feed horns on FAST's L -band receiver across Stokes I , Q U and V parameters. Using an on-the-fly mapping pattern, we conducted simultaneous sky using all beams directed toward polarization calibrators J1407+2827 J0854+2006 from to 2022. Electromagnetic simulations were also performed model...
We present 850 $\mu$m polarized continuum observations carried out with the POL-2 polarimeter mounted on James Clerk Maxwell Telescope (JCMT) towards NGC 7023 located in Cepheus Flare region. is a reflection nebula powered by Herbig Ae Be star HD 200775 and also identified as hub hub-filament cloud, LDN 1172/1174. detect submillimetre emission well northern (identified C1) eastern region of nebula. investigated polarization structure magnetic field (B-field) morphology, which found to be...
We report high angular resolution observations of linearly polarized dust emission towards the Class 0 young stellar object (YSO) NGC1333 IRAS4A (hereafter, IRAS4A) using Karl G. Jansky Very Large Array (JVLA) at K (11.5-16.7 mm), Ka (8.1-10.3 and Q bands (6.3-7.9 Atacama Millimeter (ALMA) Band 6 (1.2 mm) 7 (0.85-0.89 mm). On 100-1000 AU scales, all these consistently trace hourglass shaped magnetic field topology as shown in previous studies. In innermost 100 region IRAS4A1, polarization...
Abstract We have obtained sensitive dust continuum polarization observations at 850 μ m in the B213 region of Taurus using POL-2 on SCUBA-2 James Clerk Maxwell Telescope as part B -fields STar-forming Region Observations (BISTRO) survey. These allow us to probe magnetic field ( -field) high spatial resolution (∼2000 au or ∼0.01 pc 140 pc) two protostellar cores (K04166 and K04169) one prestellar core (Miz-8b) that lie within filament. Using Davis–Chandrasekhar–Fermi method, we estimate...
We present ALMA dust polarization and molecular line observations toward 4 clumps (I(N), I, IV, V) in the massive star-forming region NGC 6334. In conjunction with large-scale data from JCMT, Planck, NANTEN2, we make a synergistic analysis of relative orientations between magnetic fields ($\theta_{\mathrm{B}}$), column density gradients ($\theta_{\mathrm{NG}}$), local gravity ($\theta_{\mathrm{LG}}$), velocity ($\theta_{\mathrm{VG}}$) to investigate multi-scale (from $\sim$30 pc 0.003 pc)...
We present Submillimeter Array 880 $\mu$m dust polarization observations of six massive dense cores in the DR21 filament. The shows complex magnetic field structures with sizes 0.1 pc, contrast to ordered fields parsec-scale major axes appear be aligned either parallel or perpendicular filament, indicating that play an important role formation cores. However, correlation between and is less significant, suggesting during core formation, below pc scales become than above supporting a against...
Abstract We report the first high spatial resolution measurement of magnetic fields surrounding LkH α 101, part Auriga–California molecular cloud. The observations were taken with POL-2 polarimeter on James Clerk Maxwell Telescope within framework B-fields In Star-forming Region Observations (BISTRO) survey. Observed polarization thermal dust emission at 850 μ m is found to be mostly associated redshifted gas component field displays a relatively complex morphology. Two variants...
We study the HII regions associated with NGC 6334 molecular cloud observed in sub-millimeter and taken as part of B-fields In STar-forming Region Observations (BISTRO) Survey. particular, we investigate polarization patterns magnetic field morphologies these regions. Through pattern pressure calculation analyses, several bubbles indicate that gas lines have been pushed away from bubble, toward an almost tangential (to bubble) morphology. densest 6334, where morphology is similar to...
Abstract We have comprehensively studied the multiscale physical properties of massive infrared dark cloud G28.34 (the Dragon cloud) with dust polarization and molecular line data from Planck, FCRAO-14 m, James Clerk Maxwell Telescope, Atacama Large Millimeter/submillimeter Array. find that averaged magnetic fields clumps tend to be either parallel or perpendicular cloud-scale fields, while cores in clump MM4 aligned fields. Implementing relative orientation analysis (for column density...
Submillimeter dust polarization measurements of a sample 50 star-forming regions, observed with the SMA and CSO covering pc-scale clouds to mpc-scale cores, are analyzed in order quantify magnetic field importance. The misalignment $\delta$ -- local angle between emission gradient is found be prime observable, revealing distinct distributions for sources where preferentially aligned or perpendicular source minor axis. Source-averaged angles $\langle|\delta|\rangle$ fall into systematically...