Gwanjeong Kim
A5088296890- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Solar and Space Plasma Dynamics
- Astrophysical Phenomena and Observations
- Advanced Chemical Physics Studies
- Atomic and Molecular Physics
- High-pressure geophysics and materials
- Spectroscopy and Laser Applications
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Plasma Diagnostics and Applications
- Quantum Chromodynamics and Particle Interactions
- Global Energy and Sustainability Research
- Solid-state spectroscopy and crystallography
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Plasma Applications and Diagnostics
- History and Developments in Astronomy
- Nuclear Physics and Applications
- Isotope Analysis in Ecology
National Institutes of Natural Sciences
2018-2024
National Astronomical Observatory of Japan
2018-2024
Korea Astronomy and Space Science Institute
2010-2019
Korea University of Science and Technology
2013-2019
Sejong University
2019
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...
Abstract The dependence of the polarization fraction p on total intensity I in polarized submillimeter emission measurements is typically parameterized as ∝ − α ( ≤ 1) and used to infer dust grain alignment efficiency star-forming regions, with an index = 1 indicating near-total lack grains magnetic field. In this work, we demonstrate that non-Gaussian noise characteristics may produce apparent ∼ even data significant signal-to-noise Stokes Q , U emission, so robust angle. We present a...
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 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...
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...
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...
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 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...
Magnetic field is one of the key agents that play a crucial role in shaping molecular clouds and regulating star formation, yet complete information on magnetic not well constrained due to limitations observations. We study massive infrared dark cloud G035.39-00.33 from dust continuum polarization observations at 850 $\micron$ with SCUBA-2/POL-2 JCMT. The tends be perpendicular densest part main filament (F$_{M}$), whereas it has less defined relative orientation rest structure, where...
Planck Galactic Cold Clumps (PGCCs) are considered to be the ideal targets probe early phases of star formation. We have conducted a survey 72 young dense cores inside PGCCs in Orion complex with Atacama Large Millimeter/submillimeter Array (ALMA) at 1.3 mm (band 6) using three different configurations (resolutions ∼035, 10, and 70) statistically investigate their evolutionary stages substructures. obtained images continuum molecular line emission (12CO, SiO) an angular resolution ∼035 (∼140...
Abstract Measurement of magnetic field strengths in a molecular cloud is essential for determining the criticality support against gravitational collapse. In this paper, as part JCMT BISTRO survey, we suggest new application Davis–Chandrasekhar–Fermi (DCF) method to estimate distribution OMC-1 region. We use observations dust polarization emission at 450 and 850 μ m, C 18 O (3–2) spectral line data obtained with JCMT. volume density, velocity dispersion, angle dispersion box, 40″ × (5×5...
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 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...
This paper presents the results of millimeter to sub-millimeter observations CO, HCN, N2H+, and HCO+ lines in dense molecular cloud L328, which harbors L328-IRS, a Very Low Luminosity Object (VeLLO). Our analysis line width finds that 13CO N2H+ are broadened right over smallest sub-core S2 where L328-IRS is located, while they significantly narrower other regions L328. Thus, has direct association with sub-core. CO show bipolar outflow from this VeLLO an extent ∼0.08 pc. The momentum flux...
Based on the 850 $\mu$m dust continuum data from SCUBA-2 at James Clerk Maxwell Telescope (JCMT), we compare overall properties of Planck Galactic Cold Clumps (PGCCs) in $\lambda$ Orionis cloud to those PGCCs Orion A and B clouds. The clouds are well known active star-forming regions, while has a different environment as consequence interaction with prominent OB association giant Hii region. have higher temperatures ($Td=16.13\pm0.15$ K) lower values emissivity spectral index ($...
Abstract Prestellar cores are self-gravitating dense and cold structures within molecular clouds where future stars born. They expected, at the stage of transitioning to protostellar phase, harbor centrally concentrated (sub)structures that will seed formation a new star or binary/multiple stellar systems. Characterizing this critical evolution is key our understanding formation. In work, we report detection high-density on thousand-astronomical-unit (au) scale in sample prestellar cores....
[Abridged] We carried out optical polarimetry of five dense cores, (IRAM 04191, L1521F, L328, L673-7, and L1014) which are found to harbour VeLLO. This study was conducted mainly understand the role played by magnetic field in formation very low substellar mass range objects using polarisation. The angular offsets between envelope direction (inferred from polarisation measurements) outflow position angles VeLLOs IRAM L1014 be 84$^\circ$, 53$^\circ$, 24$^\circ$, 08$^\circ$, 15$^\circ$,...
Abstract We present the 850 μ m polarization observations toward IC 5146 filamentary cloud taken using Submillimetre Common-User Bolometer Array 2 (SCUBA-2) and its associated polarimeter (POL-2), mounted on James Clerk Maxwell Telescope, as part of B -fields In STar forming Regions Observations. This work is aimed at revealing magnetic field morphology within a core-scale (≲1.0 pc) hub-filament structure (HFS) located end parsec-scale filament. To investigate whether observed traces in HFS,...
We present the results of simultaneous 450 $\mu$m and 850 polarization observations toward massive star forming region NGC 2071IR, a target BISTRO (B-fields in Star-Forming Region Observations) Survey, using POL-2 polarimeter SCUBA-2 camera mounted on James Clerk Maxwell Telescope. find pinched magnetic field morphology central dense core region, which could be due to rotating toroidal disk-like structure bipolar outflow originating from young stellar object, IRS 3. Using modified...
We present 850 $\mu$m dust polarization observations of the massive DR21 filament from B-fields In STar-forming Region Observations (BISTRO) survey, using POL-2 polarimeter and SCUBA-2 camera on James Clerk Maxwell Telescope. detect ordered magnetic fields perpendicular to parsec-scale ridge main filament. sub-filaments, are mainly parallel filamentary structures smoothly connect compare Planck study field 0.1--10 pc scales. The revealed in data well aligned with those data, indicating a...
Abstract We present observations of polarized dust emission at 850 μ m from the L43 molecular cloud, which sits in Ophiuchus cloud complex. The data were taken using SCUBA-2/POL-2 on James Clerk Maxwell Telescope as a part BISTRO large program. is dense ( <?CDATA ${N}_{{{\rm{H}}}_{2}}\sim {10}^{22}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>N</mml:mi> </mml:mrow> <mml:mi mathvariant="normal">H</mml:mi> <mml:mn>2</mml:mn>...
We present the POL-2 850 $\mu$m linear polarization map of Barnard 1 clump in Perseus molecular cloud complex from B-fields In STar-forming Region Observations (BISTRO) survey at James Clerk Maxwell Telescope. find a trend decreasing fraction as function total intensity, which we link to depolarization effects towards higher density regions cloud. then use data infer plane-of-sky orientation large-scale magnetic field 1. This runs North-South across most cloud, with exception B1-c where it...
We report the detection of four new hot corino sources, G211.47-19.27S, G208.68-19.20N1, G210.49-19.79W and G192.12-11.10 from a survey study Planck Galactic Cold Clumps in Orion Molecular Cloud Complex with Atacama Compact Array (ACA). Three sources had been identified as low mass Class 0 protostars Herschel Protostar Survey (HOPS). One source lambda Orionis region is firstly reported protostellar core. have observed abundant complex organic molecules (COMs), primarily methanol but also...