Aya E. Higuchi

Unveiling the gas-and-dust disk structure in HD 163296 using ALMA observations

Aims. The aim of this work is to study the structure of the protoplan etary disk surrounding the Herbig Ae star HD 163296. Methods. We have used high-resolution and high-sensitivity ALMA observations of the CO(3‐2) emission line and the continuum at 850µm, as well as the 3- dimensional radiative transfer code MCFOST to model the data presented in this work. Results. The CO(3‐2) emission unveils for the first time at sub-millim eter frequencies the vertical structure details of a gaseou s disk in Keplerian rotation, showing the back- and the front-side of a flared disk. Continuum emission at 850 µm reveals a compact dust disk with a 240 AU outer radius and a surface brightness profil e that shows a very steep decline at radius larger than 125 AU. The gaseous disk is more than two times larger than the dust disk, with a similar critical radius but with a shallower radial pr ofile. Radiative transfer models of the continuum data confirms the need for a s harp outer edge to the dust disk. The models for the CO(3‐2) channel map require the disk to be slightly more geometrically thick than previous models suggested, and that the temperature at which CO gas becomes depleted (frozen-out) from the outer regions of the disk midplane is T < 20 K, in agreement with previous studies.

THE DYNAMICAL STATE OF THE SERPENS SOUTH FILAMENTARY INFRARED DARK CLOUD

We present the results of N_2H^+ (J = 1-0) observations toward Serpens South, the nearest cluster-forming, infrared dark cloud. The physical quantities are derived by fitting the hyperfine structure of N_2H^+. The Herschel and 1.1 mm continuum maps show that a parsec-scale filament fragments into three clumps with radii of 0.1-0.2 pc and masses of 40-230 M_☉. We find that the clumps contain smaller-scale (~0.04 pc) structures, i.e., dense cores. We identify 70 cores by applying CLUMPFIND to the N_2H^+ data cube. In the central cluster-forming clump, the excitation temperature and line-width tend to be large, presumably due to protostellar outflow feedback and stellar radiation. However, for all the clumps, the virial ratios are evaluated to be 0.1-0.3, indicating that the internal motions play only a minor role in the clump support. The clumps exhibit no free fall but exhibit low-velocity infall, and thus the clumps should be supported by additional forces. The most promising force is the globally ordered magnetic field observed toward this region. We propose that the Serpens South filament was close to magnetically critical and ambipolar diffusion triggered the cluster formation. We find that the northern clump, which shows no active star formation, has a mass and radius comparable to the central cluster-forming clump and is therefore a likely candidate of a pre-protocluster clump. The initial condition for cluster formation is likely to be a magnetically supported clump of cold, quiescent gas. This appears to contradict the accretion-driven turbulence scenario, for which the turbulence in the clumps is maintained by the accretion flow.

L483: Warm Carbon-chain Chemistry Source Harboring Hot Corino Activity

The Class 0 protostar, L483, has been observed in various molecular lines in the 1.2 mm band at a sub-arcsecond resolution with ALMA. An infalling-rotating envelope is traced by the CS line, while a very compact component with a broad velocity width is observed for the CS, SO, HNCO, NH

Sgr B2(N): A bipolar outflow and rotating hot core revealed by ALMA

_2

Initial Results from Nobeyama Molecular Gas Observations of Distant Bright Galaxies

CHO, and HCOOCH

Vertical structure of the transition zone from infalling rotating envelope to disc in the Class 0 protostar, IRAS 04368+2557

_3

Chemical Survey toward Young Stellar Objects in the Perseus Molecular Cloud Complex

lines. Although this source is regarded as the warm carbon-chain chemistry (WCCC) candidate source at a 1000 au scale, complex organic molecules characteristic of hot corinos such as NH

Rotation in the NGC 1333 IRAS 4C Outflow

_2

Detection of Submillimeter-wave [C i] Emission in Gaseous Debris Disks of 49 Ceti and β Pictoris

CHO and HCOOCH

New observing system of the 45-m telescope at Nobeyama Radio Observatory

_3