Jungmi Kwon

MAGNETIC FIELD STRUCTURE OF THE HH 1-2 REGION: NEAR-INFRARED POLARIMETRY OF POINT-LIKE SOURCES

The HH 1–2 region in the L1641 molecular cloud was observed in the near-infrared (IR) J, H, and Ks bands, and imaging polarimetry was performed. Seventy-six point-like sources were detected in all three bands. The near-IR polarizations of these sources seem to be caused mostly by the dichroic extinction. Using a color–color diagram, reddened sources with little IR excess were selected to trace the magnetic field structure of the molecular cloud. The mean polarization position angle of these sources is about 111 ◦ , which is interpreted as the projected direction of the magnetic field in the observed region of the cloud. The distribution of the polarization angle has a dispersion of about 11 ◦ , which is smaller than what was measured in previous studies. This small dispersion gives a rough estimate of the strength of the magnetic field to be about 130 μG and suggests that the global magnetic field in this region is quite regular and straight. In contrast, the outflows driven by young stellar objects in this region seem to have no preferred orientation. This discrepancy suggests that the magnetic field in the L1641 molecular cloud does not dictate the orientation of the protostars forming inside.

GMTNIRS (Giant Magellan Telescope near-infrared spectrograph): design concept

We are designing a sensitive high resolution (R=60,000-100,000) spectrograph for the Giant Magellan Telescope (GMTNIRS, the GMT Near-Infrared Spectrograph). Using large-format IR arrays and silicon immersion gratings, this instrument will cover all of the J (longer than 1.1 μm), H, and K atmospheric windows or all of the L and M windows in a single exposure. GMTNIRS makes use of the GMT adaptive optics system for all bands. The small slits will offer the possibility of spatially resolved spectroscopy as well as superior sensitivity and wavelength coverage. The GMTNIRS team is composed of scientists and engineers at the University of Texas, the Korea Astronomy and Space Science Institute, and Kyung Hee University. In this paper, we describe the optical and mechanical design of the instrument. The principal innovative feature of the design is the use of silicon immersion gratings which are now being produced by our team with sufficient quality to permit designs with high resolving power and broad instantaneous wavelength coverage across the near-IR.

NEAR-IR POLARIMETRY AROUND 30 DORADUS: I. SEPARATION OF THE GALACTIC SOURCES

A 20 0 × 20 0 region around 30 Doradus in the Large Magellanic Cloud (LMC) is observed and analyzed in the near-infrared. We obtain polarimetry data in the J, H, and Ks bands using the SIRIUS polarimeter SIRPOL at the Infrared Survey Facility 1.4 m telescope. We measure the Stokes parameters of 2562 point-like sources to derive the degree of polarization and the polarization position angles. We discuss the statistics of the groups classified by color-magnitude diagram and proper motions of the sources, in order to separate the Galactic foreground sources from those present in the LMC. We notice that groups classified by the proper motion data show a tendency towards different polarimetric properties.

The JCMT BISTRO Survey: The Magnetic Field Strength in the Orion A Filament

We determine the magnetic field strength in the OMC 1 region of the Orion A filament via a new implementation of the Chandrasekhar-Fermi method using observations performed as part of the James Clerk Maxwell Telescope (JCMT) B-Fields In Star-Forming Region Observations (BISTRO) survey with the POL-2 instrument. We combine BISTRO data with archival SCUBA-2 and HARP observations to find a plane-of-sky magnetic field strength in OMC 1 of

SCExAO AND GPI Y JH BAND PHOTOMETRY AND INTEGRAL FIELD SPECTROSCOPY OF THE YOUNG BROWN DWARF COMPANION TO HD 1160

B_{rm pos}=6.6pm4.7

Galaxy evolution studies with the SPace IR Telescope for Cosmology and Astrophysics (SPICA): the power of IR spectroscopy

mG, where

MAGNETIC FIELD OF THE VELA C MOLECULAR CLOUD

delta B_{rm pos}=4.7

NEAR-INFRARED IMAGING POLARIMETRY OF INNER REGION OF GG TAU A DISK

mG represents a predominantly systematic uncertainty. We develop a new method for measuring angular dispersion, analogous to unsharp masking. We find a magnetic energy density of

High-contrast imaging of epsilon Eridani with ground-based instruments

sim1.7times 10^{-7}

Unbiased large spectroscopic surveys of galaxies selected by SPICA using dust bands

Jm