コロキウム」カテゴリーアーカイブ

NEAR INFARED CIRCULAR POLARIZATION IMAGES OF NGC 6334 V / Association of Polar faculae with the Polar magnetic patches as observed by Hinode

[Speaker 1]
Jungmi Kwon
[Title]
NEAR INFARED CIRCULAR POLARIZATION IMAGES OF NGC 6334 V
[Abstract]
We present results from deep imaging polarimetry measurements of circularly and linearly polarized light towards the massive star forming region NGC 6334-V. These observations show high degrees of circular polarization (CP) in the Ks band of as much as 22 % with an asymmetric positive/negative pattern, measured in the infrared nebula associated with the outflow. The CP region is very extended (~80″ or 0.65 pc). Both the large CP and the extended size of the CP region are comparable to those seen in the Orion CP region. The CP pattern is shifted along the axial axis and such an asymmetry does not conform to the classical alternating symmetry seen in other objects and models.
The asymmetry may be a clue indicating the range of influence of a helical field. Three-dimensional Monte Carlo light-scattering models are used to show that this may occur with a scattering geometry, which contains a dusty envelope surrounding the accretion disk as well as aligned grains. The detection of the large and extended CP in this source and the Orion supports the CP origin of the biological homochirality on Earth.
————————————————————————————————————-
————————————————————————————————————-
[Speaker 2]
Anjali John K
[Title]
Association of Polar faculae with the Polar magnetic patches as observed by Hinode
[Abstract]
The polar region of the Sun, as observed with Hinode SOT/SP is found to be covered by patches that harbour strong magnetic field and that the large unipolar patches with flux > 10^18 Mx determine the polarity of the polar fi eld. It is also observed that there are small
bipolar patches (< 1018Mx) with balanced flux in the polar region. The polar faculae, the small-scale bright magnetic structures observed at heliographic latitudes > 70 deg., have been considered as a good proxy for the polar magnetic fi eld. The aim of this study is to understand the magnetic properties of faculae, which are believed to be associated with the polar magnetic patches. We analysed data of the north polar region taken by the Hinode/SOT- spectropolarimeter (SP) in September 2007. There are patches without faculae and they outnumber those with faculae. Faculae are present in all the patches with flux > 10^19 Mx. Magnetic patches are not uniformly bright but contain smaller faculae inside. We find that a positive correlation exists between total flux and intensity of faculae within the magnetic patches and that the faculae intensity depends on cosine of the heliocentric angle .

Absolute Proper Motion of CB 3 Away from the Galactic Plane Measured with VERA in a Galactic Superbubble / Powerful high-contrast imaging techniques on direct detection of exoplnaets

[Speaker 1]
Nobuyuki Sakai
[Title]
Absolute Proper Motion of CB 3 Away from the Galactic Plane Measured with VERA in a Galactic Superbubble
[Abstract]
TBA
———————————————————————————
[Speaker 2]
Daehyun Oh
[Title]
Powerful high-contrast imaging techniques on direct detection of exoplnaets
[Abstract]
Direct detections of very faint exoplanets and brown dwarfs near bright stars are essential in understanding substellar for- mation and evolution around stars. The task is dauntingly difficult. The exoplanet or brown dwarf image is usually much fainter than the background from the brilliant PSF image. Aside from the Poisson noise, ground-based tele- scopes suffer from atmospheric turbulence that produces random short-lived speckles that mask faint companions. I will talk about two techniques called ADI and LOCI, can be used on ground-based altitude/ azimuth telescopes to subtract a significant fraction of the stellar quasistatic noise.

Near-infrared Imaging Polarimetric Study of Orion A molecular cloud / Revealing the lower side of IMF and Searching for planetary mass objects

[Speaker 1]
Amnart Sukom
[Title]
Near-infrared Imaging Polarimetric Study of Orion A molecular cloud
[Abstract]
Orion Molecular Cloud (OMC) is the nearest region of massive star formation, which was intensively studied as a representative of star-forming regions. The northern part of Orion A molecular cloud,
OMC-1, -2, -3, and the southern part, OMC-4, are often referred to Integral Shape Filament (ISF), and contain intermediate-sized molecular cores, low and high mass young stars, dozens of Herbig-Haro (HH) objects and molecular outflows.
We present the first wide-field deep near-infrared images of 15′ x 50′ area of the Orion A ISF, obtained by SIRPOL, simultaneous JHKs imaging polarimeter on the IRSF telescope. Point-source aperture polarimetry suggest the magnetic field orientations are perpendicular to the elongation of the filament. Moreover, the hour-glassed shape magnetic field pattern in OMC-1 is confirmed by our polarization maps.
————————————————————
————————————————————
[Speaker 2]
Takuya Suenaga
[Title]
Revealing the lower side of IMF and Searching for planetary mass objects
[Abstract]
Initial mass function (IMF) is one of the most important physical parameters in the star formation theory. Many author have investigated the IMF for a long time, however it has not been completely understood. I’m studying the lower side of IMF, in particular the bottom. Here, I’ll introduce some studies related to IMF, and my ongoing works.

Static compression process of dust aggregates in protoplanetary disks

[Speaker 1]
Akimasa Kataoka
[Title]
Static compression process of dust aggregates in protoplanetary disks
[Abstract]
Planetesimal formation process in protoplanetary disks is a key issue in planet formation. Recently, internal density evolution of dust aggregates with collisional compression has been proposed to solve this problem (Okuzumi et al. 2012). However, other compression processes, which are caused by gas drag or self gravity, have not been considered. Such compression processes may differ from collisional compression processes, and thus it may greatly affect internal density evolution of dust aggregates. Therefore, we investigated static compression processes of porous aggregates by calculating N-body
simulation with considering direct interaction forces (Wada et al. 2007), and we determine the equation of state of porous aggregates.

Galactic-scale Outflow at z>4 revealed by Adaptive Optics / Spectroscopic Follow-up Observation of a High-redshift Protocluster Candidate

[Speaker 1]
Takatoshi Shibuya
[Title]
Galactic-scale Outflow at z>4 revealed by Adaptive Optics
[Abstract]
Characterization of the large-scale galactic outflow is very important to understand many astrophysical phenomena at high-z, such as the escape of LyA photons from the galaxy, the relation between the galaxy populations, and IGM metal-enrichment history. Although galactic outflows are ubiquitously found in star-forming galaxies at 2