総研大天文科学専攻ウェブログ

Time evolution of X-ray jet's velocity

2012-12-04T09:14:59Z

[Speaker 1] Nobuharu Sako [Title] Time evolution of X-ray jet's velocity [Abstract] An X-ray jet is a kind of flares in the Sun. The model of X-ray jets based on magnetic reconnection (Shibata et al. 1992) predicts that two flows with the different velocities are included in one X-ray jet. The velocity of one flow roughly equals to Alfven velocity (~1000 km/s), and the flow is accelerated by the magnetic force. The other one is accelerated by the pressure gradient and its velocity is similar to the sound velocity (~200 km/s). However, the observational results (e.g. Shimojo et al. 2000) before the Hinode era show that the velocities of most X-ray jets are slower than the sound velocity. Because the X-ray telescope (XRT) aboard the Hinode satellite has capability to observe the corona with the high temporal (< 1 min) and high spatial (~ 1 arcsec) resolutions, the XRT data revealed that an X-ray jet includes two components with the different velocities (Cirtain et al. 2007). The properties of the components have some differences from the model. For example, the components are not observed simultaneously. One component with sound velocity continues to appear until the peak time of the X-ray jet. The other one with Alfven velocity appear transiently. There is only one report using four X-ray jets by Cirtain et al. (2007) and their result does not show the time evolution of the velocity in X-ray jets, yet. In order to reveal the evolution of the X-ray jet's velocity, and investigate how the high velocity component occurs transiently in an X-ray jet, we detected 13 polar X-ray jets from the coronal data observed with XRT and investigated the time evolution of the velocity of the X-ray jets. The result shows that it is common that an X-ray jet includes the plural components with the different velocities. However, we could detect component with Alfven velocity in only three of the 13 events. In the talk, I introduce our data analysis and show the details of our result.

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

2012-11-08T01:20:26Z

[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 field. 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 field. 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 .

総合研究大学院大学　天文科学専攻　特別公開 2012

2012-11-01T08:16:56Z

今年も例年通り、総合研究大学院大学/天文科学専攻の特別公開が、国立天文台の特別公開に合わせ2012/10/26～27の期間、共同で開催されました。天文科学専攻に所属する約30名の学生は、それぞれの所属部署と総研大の両方で準備を進めながら、当日は"総研大生の研究ライフ2012"と言う企画運営に携わりました。当日はお子さんから10～20代の若者、お子さんの親御さん世代の30~40代、更にはお孫さんがいらっしゃる50~60代の方々と幅広い年齢層の方々が来場されました。企画中にアンケートを取った結果（アンケート集計人数は263人）、"大学院での生活がどのようなものなのか、日常・非日常で分けていて、とてもイメージがつきやすかったです。非日常で、色んな観測所で観測をしているのが印象に残りました"と言うコメントを頂き、学生らしさが出た企画が好評を博していました。また、"（総研大の）存在を初めて知ったので、何もかもが印象的でした"と言うコメントなども頂き、総研大と言う存在を初めて知った方も多くいらっしゃったようです。総研大のPRを兼ねている特別公開なので、企画が持っている目標が十二分に達成されたと言えそうです。一方で、所属部署と総研大企画のシフト調整が直前まで行われていなかったり、折角上手に出来ている動画の配置場所が悪かったりと、反省点も挙げられています。来年の企画立案の際にはこれらの反省を活かし、更に良いものにして貰えればと思います。

毎年好評の総研大企画の景品や会場の様子！ クイズの景品は毎年豪華！学生の日常を紹介中！クイズに正解すると、景品が貰えます！

文責：　総合研究大学院大学　天文科学専攻　博士過程4年　坂井伸行

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

2012-10-30T05:19:37Z

[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

2012-10-16T07:07:22Z

[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

2012-10-09T08:19:37Z

[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

2012-10-04T01:30:30Z

[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

Measurement of Mass Distribution of Dark Matter Using Weak Gravitational Lensing /Nature and Nurture Effects on the Formation and Evolution of Cluster Galaxies /the determination of the masses of dark matter halos by clustering properties of sBzK galaxies

2012-07-10T06:12:56Z

[Speaker 1] Junya Sakurai [Title] Measurement of Mass Distribution of Dark Matter Using Weak Gravitational Lensing [Abstract] According to the observational results from high-z supernovae and CMB, the universe almost consists of the dark matter and the dark energy. Unfortunately, these components haven't entirely understood yet. To understand these unknown objects, some techniques are proposed. One of these techniques is the gravitational lensing. The gravitational lensing is the effect that the shape of the background galaxy is distorted by the foreground object. We can estimate the mass distribution of the foreground object from the distortion of the background galaxy. Even if the foreground object is the dark matter, we can estimate the mass distribution of the dark matter. In my talk, I present the gravitational lensing of the basis of this technique. ------------------------------------------------------------ ------------------------------------------------------------ [Speaker 2] Rhythm Shimakawa [Title] Nature and Nurture Effects on the Formation and Evolution of Cluster Galaxies [Abstract] In low-redshift clusters, most galaxies appear to be quiescent. These galaxies tend to be elliptical or S0 galaxies, which constitute conspicuous red-sequence on the color-magnitude diagrams. In contrast, in high-redshift proto-clusers, galaxies tend to have complicated morphologies and high star-formation rates (SFRs) of 100s $M_\odot/yr$. Such truncation in star formation activities can be caused by "nature" effects, i.e.\ accelerated galaxy formation in dense environments, and/or by "nurture" effects, i.e.\ galaxy-galaxy interactions/mergers and gas-stripping (e.g.\ Kodama et al. 2001). Recent works (Daddi et al 2007; Mannucci et al. 2010) have presented double (main and sub) sequences of star forming galaxies on the SFR versus gas-mass plane, and a fundamental metallicity relation (FMR) where gaseous metallicity of star forming galaxies in the SDSS are determined as a function of stellar mass and SFR, both of which describe the modes of star formation and the evolutionary stages of galaxies. Motivated by these observational phenomena, we now aim to explore these relationships (main/sub sequenes and FMR) in clusters/proto-clusters based on near-infrared specroscopy (FMOS/MOIRCS on Subaru) and ALMA observations (Mahalo-Subaru and Gracias-ALMA projects). By comparing these relationships in clusters with the field counterparts, we will quantify the roles of environments to shape galaxies, and thus understand the origin of environmentally dependent galaxy formation and evolution. ------------------------------------------------------------ ------------------------------------------------------------ [Speaker 3] Shogo Ishikawa [Title] the determination of the masses of dark matter halos by clustering properties of sBzK galaxies [Abstract] The existence of vast "dark matter halos" around luminous galaxies is strongly implied by some evidence. It is extremely difficult, however, to measure the masses of high-redshift galaxies' dark matter halos. One method to quantify them is to measure the amplitude of galaxy clustering, since CDM models predict a monotonic correlation that more massive halos are clustered more strongly. Measuring galaxy clustering requires a large sample from wide area.However, it is still hard to do this at z~2, where BzK color selection can allow us to accumulate larger samples, due to a lack of combination of wide optical and NIR data. I will show our challenge to overcome this difficulty. --------------------------------------------------

Spectroscopy of blue straggler stars in Galactic open cluster NGC 2682 (M67) / VERA observations of SiO masers in Symbiotic star R Aquarii

2012-07-03T08:15:17Z

[Speaker 1] Zhao Zhengshi [Title] Spectroscopy of blue straggler stars in Galactic open cluster NGC 2682 (M67) [Abstract] In this presentation, we report spectroscopic analysis of eight blue straggler stars (BSSs) and three turn-off stars (TOs) in the old open cluster (OC) NGC 2682. From the high resolution (R~60,000) spectra obtained by the Subaru / HDS, we derived radial velocity, rotation velocity, and calculated chemical abundances of lithium, carbon and oxygen. Radial velocity of the target stars is consistent with the mean radial velocity of member stars of the cluster. Thus, we confirm the targets are indeed the real members of the cluster. Rotation velocity of BSSs distributes in a wide range of few km/s to hundred km/s, while those of TOs is restricted to a small value (vsini ≦7 km/s) . Both mass transfer scenario and collision scenario are expected to spin up BSSs. Target stars with measured Li abundances show a good agreement to the trend between A(Li) and Teff found in previous works . Moreover, BSSs have C and O abundances not significantly different from those of the TOs. Exceptions are BSS S997 and S1273. S997 shows a slight enhancement in O abundance, while S1273 shows a significant depletion in C abundance and a slight depletion in O abundance compared to other BSSs and TOs in the same cluster. These anomalies in C and O abundances may be interpreted by mass transfer scenario. ------------------------------------------------------------ ------------------------------------------------------------ [Speaker 2] Cheul Hong Min [Title] VERA observations of SiO masers in Symbiotic star R Aquarii [Abstract] R Aquarii (R Aqr) is one of the closest symbiotic systems and one of the SiO maser sources associated with the Mira variable in Symbiotic star. These systems are very interesting target, and R Aqr is very exciting laboratory because of the existence of jet-like feature. Though observations of the system have not yielded consistent values of the orbital parameters, the binary parameters of the orbit give an evidence whether or not Roche lobe outflow in the long period variable and interacting stellar winds of the formation of accretion disk and jet in secondary star. VERA has performed the observations toward R Aqr since 2004. VERA its unique observation system is a powerful tool for astrometry, and we can hopefully obtain information about its orbital motions. In this presentation, I will present the result of VERA observations for R Aqr.

Evaluation of pointing error on ALMA ACA antenna / Testing the formation scenario of massive star by CH3OH maser

2012-06-19T04:54:01Z

[Speaker 1] Ayumu Matsuzawa M2, SOKENDAI, Mitaka（supervisor : Satoru Iguchi） [Title] Evaluation of pointing error on ALMA ACA antenna [Abstract] The pointing error is difference between actual direction and directed direction of the antenna. I evaluate the activity of scientific performance by pointing error for ALMA antenna. The pointing error of ALMA antenna has three components: The components of antenna, the component of the optical pointing telescope and the components of the atmosphere. The purpose of my research is extract and evaluates the only component of radio antenna. Because, the component of antenna specification be established. Therefore, the component of antenna can correctly evaluate rather than other two components. For evaluate the pointing error, I estimate the pointing error from measurement data. The measurement of pointing error uses the optical pointing telescope (OPT). OPT installed in surface of antenna, and shooting a star by CCD in OPT. In the image of CCD, the pointing error assumed the difference center of image between centroid of star. But, this image included same noise. I made a program for remove the noise in image. I confirm that this program perform in ideal image as expected. The component of antenna has some components (wind, thermal, servo, meterology). For extract these components, I measure the pointing error by Long tracking (measure the pointing error when tracking the one source over 15min). It can extract using the data of resolver and thermocouple. Now, I measure the pointing error by many long tracking, also I will measure the pointing error by Fast switching (measure the pointing error when the antenna is moving fast). After this, I will evaluate the component of radio antenna from pointing error. By this research, I expect improve the precision of pointing error for ALMA antenna. ------------------------------------------------------------ ------------------------------------------------------------ [Speaker 2] Nagisa Shino D1, SOKENDAI, Mitaka（supervisor : Mareki Honma） [Title] Testing the formation scenario of massive star by CH3OH maser [Abstract] Now classⅠ CH3OH maser is thought to be associated with outflow, while classⅡ CH3OH maser is thought to be associated with accretion disc. If this is true, classⅠ CH3OH maser is expected to be distributed perpendicularly with respect to rotating disk. Detecting (or rejecting) this will play a major role in understanding the scenario of massive star formation. To do this, we plan to observe distributions of two classes of CH3OH masers with VLBI. For that purpose, first we have to look fortarget sources in which both of classes are detected. We performed the single-dish observations of both classes of CH3OH maser using Nobeyama 45m and Yamagucchi 32m telescopes. As a result, we discovered 89 sources detected in both classes.

The outflow from accretion disk around the Black Hole / Finding Brown Dwarfs in star formation region with subaru telescope

2012-06-14T01:42:03Z

[Speaker 1] Katsuya Hashizume [Title] The outflow from accretion disk around the Black Hole [Abstract] The accretion disks around Black Holes(BHs) are believed to drive high energy astrophysical phenomena , such as high-energy radiation, disk outflows, and jets of Active Galactic Nuclei and black hole binaries. But, structure of the disks and mechanisms of driving outflow have poorly understood. Especially, super-Eddington accretion disks, of which luminosity exceeds the Eddington luminosity, is a hot debated issue. If the super-Eddington disks are feasible, the ultra luminous X-ray sources are explained without assuming intermediate mass black holes. By two-dimensional radiation-hydrodynamics (2D-RHD) simulations, super-Eddington accretion disks around BHs are successfully reproduced, implying that quasi-steady super-Eddington accretion is possible (Ohsuga et al. 2005).However, the computational domain of the simulations is restricted tobe 500 Rs (Schwarzschild radius).Thus, the behavior of outflows at the distant region (>500Rs) is not investigated. The structure of the super-Eddington flows might change if the outflowing matter of >500Rs get back to the vicinity of the black hole. In order to understand more realistic structure and dynamics of the super-Eddington flows, it is needed to reperform 2D-RHD simulations with much larger computational domain. In this talk, I present the fundamental mechanisms of BH accretion disks and outflows,and also my research plan of master thesis. ------------------------------------------------------------ ------------------------------------------------------------ [Speaker 2] Daehyeon Oh [Title] Finding Brown Dwarfs in star formation region with subaru telescope [Abstract] TBD

国立天文台特別公開講座/総研大天文科学専攻入試ガイダンスを開催

2012-06-07T02:09:42Z

２０１２年５月２６日に（土）に国立天文台（三鷹キャンパス）で、特別公開講演および総研大入試ガイダンスが行われました。今年は、３０名以上の方々にご参加いただき、大変な盛り上がりを見せました。また、学生のみならず一般の方も参加され、日本の天文学を国立天文台から社会に発信する良い機会になりました。特別公開講演では、「新領域を切り開く天文学」をテーマとして、ハワイ観測所の宮崎聡准教授、理論研究部の田中雅臣助教、天文データセンターの大石雅寿准教授による公演が行われました。装置開発からシミュレーションに至るまで最先端の研究を身近に感じられ、参加者にとって大変有意義な時間となりました。また、参加者による質疑応答では、今後日本の天文学がどのように発展して、どんな可能性を秘めているのか、白熱した議論が繰り広げられました。教員との相談会では、興味・関心のある分野の教員に直接話を聞くことができ、大学院の概要，入試や入学後の学生生活，実際の研究活動などの質疑応答が活発に行われました。また、院生とも交流する場が設けられ、実際の研究生活や、授業、実習などについて詳しく聞けるとても有意義な場となりました。このように、多くの方々にご参加いただけたことで、積極的な質疑応答が交わされ、参加者にも講演者にも大変意義のあるガイダンスとなりました。田中助教の講演内容参加者から質問を受ける大石准教授教員との相談会の様子ハワイからもskypeで接続して対応

Investigating the coevolution between SMBHs and Galaxies at z~3 / Morphological Evolution of Passively Evolving Early-type Galaxies at z~2

2012-06-07T02:01:45Z

[Speaker 1] Yuriko Saito [Title] Investigating the coevolution between SMBHs and Galaxies at z~3 [Abstract] In the local universe, there is a tight correlation between the masses of super massive black holes (SMBHs) and stars in the spheroidal components (bulge and elliptical galaxies), suggesting that their formation is physically closely related. Various models assuming different physical mechanisms are proposed to explain the observational result at z=0. Since these models predict different redshift evolution of the SMBH-spheroid mass ratio, it is important to observationally constrain the mass ratio at high redshift. Since the predicted difference becomes larger at higher redshift, going to higher redshift is better to distinguish among these models, but at the same time observational difficulties increase at higher redshift. By taking into account these factors, we have concluded that z=3-3.5 is the best redshift range. However, previous studies have mostly been limited to z<2. We have embarked on (1) systematic near-infrared spectroscopy of z=3-3.5 QSOs, to derive the SMBH masses, based on the the Balmer beta emission line width and nearby continuum luminosity, using 3--4m telescopes, and (2) Subaru LGS-AO near-infrared multi-color imaging observations, to estimate spheroidal stellar masses in the host galaxies of these QSOs. The use of Balmer beta line, PSF-stable Subaru LGS-AO, and multi-color imaging data make our study the most reliable and promising to investigate the redshift evolution of SMBH-spheroid mass ratio and to observationally constrain the physical mechanism behind the correlation. In this talk, I will present our strategy and current progress of this project. ------------------------------------------------------------ ------------------------------------------------------------ [Speaker 2] Sumire Tatehora [Title] Morphological Evolution of Passively Evolving Early-type Galaxies at z~2 [Abstract] Understanding the formation of massive elliptical galaxies is an unsolved problem. The discovery of a widespread population of passively evolving early-type galaxies (ETGs) at z>1.4 have proved that quenching star formation in most massive galaxies was well under way by z~2. And such objects are extremely compact, having much smaller effective radii compared to local ETGs with the same stellar mass, while massive ETGs with similar effective radii have also been found. If we understand their dynamical and structural properties in detail, it is important to measure the stellar velocity dispersion of galaxies. However the number of high-z ETGs with measurement of the velocity dispersion is still extremely small. So we have deep NIR spectroscopic observations of 33 massive passive BzK-selected galaxies (pBzKs) from the COSMOS field using Subaru/MOIRCS. In this talk, I will present progress of an analysis.

Surveys for Lyman Alpha Blobs at z=2 and 3 / Infrared Linear and Circular Polarimetry of the NGC 6334 Star Forming Region

2012-05-29T02:05:14Z

[Speaker 1] Takatoshi Shibuya [Title] Surveys for Lyman Alpha Blobs at z=2 and 3 [Abstract] LyA blobs (LABs) are mysterious extended sources at z ~ 2-6. Because LABs are thought to closely relate to the formation of / the feedback from massive galaxies, investigating the origin of their brightness and spatial extent is quite important. However, despite intensive observational and theoretical approaches, the formation mechanisms of LABs have been poorly constrained. In order to understand their hidden total energy budget and relationship with other galaxy populations, such as compact Lyman Alpha Emitters (LAEs) or massive Sub-Millimeter Galaxies (SMGs) selected by using various wavebands, surveys for LABs in well-observed fields in multi-wavelengths are crucially required. For this purpose, we have undertaken narrow-band imaging surveys in 2 MUSYC fields, the Extended Chandra Deep Field-South and the Extended Hubble Deep field-South, for LABs at z=2.1 and 3.1. In this presentation, I will provide our preliminary results. ------------------------------------------------------------ ------------------------------------------------------------ [Speaker 2] Jungmi Kwon [Title] Infrared Linear and Circular Polarimetry of the NGC 6334 Star Forming Region [Abstract] Magnetic fields have been thought to play a crucial role in regulating accretion onto protostars, both in powering and shaping outflows and removing angular momentum from disk material, to allow the protostar to gain mass. However, the precise role of the magnetic field is poorly understood and evidence for its shape and structure has not been forthcoming. Getting evidence for the morphology of these fields has been tricky though - and this is an area in which polarimetry can help. In particular, circular polarization can provide evidence for changing grain/field alignment directions along the line-of-sight and hence the presence of twisting fields. However, the observational database of circular polarimetry in star forming regions is still very small. In this presentation, we present deep linear and circular polarization images of the NGC 6334 massive star-formation complex observed in the near-infrared bands.

Preliminary study on the characteristics of polar faculae / Searching for Planetary Mass Objects in Taurus Molecular Cloud

2012-05-23T02:07:25Z

[Speaker 1] John K Anjali [Title] Preliminary study on the characteristics of polar faculae [Abstract] TBA ------------------------------------------------------------ ------------------------------------------------------------ [Speaker 2] Takuya Suenaga [Title] Searching for Planetary Mass Objects in Taurus Molecular Cloud [Abstract] A large number of substellar-mass objects isolated in star forming regions are now known, with masses ranging from those of brown dwarfs (BDs) to Planetary Mass Objects (PMOs). However, it is not well known the frequency of these objects or how they are formed. We have conducted deep i', z' observations toward the Taurus molecular cloud. Based on the color selection, we have first found PMO candidates in Taurus. After planning spectroscopic follow-up, if these are confirmed to be YSOs and low effective temperature, we can suggest that the Initial Mass Function in Taurus continues into the planetary mass.