Abstracts (Oral)ver.20171112

Day 1 (November 14)

Presenter: Masashi Omiya (NAOJ)

Title
East-Asian collaboration to search for planets around giant stars
Abstract
We have been carrying out an international collaboration to searchfor planets around giant stars in East-Asia (East-Asian Planet Search
Network, EAPS-Net) . The collaboration aims to detect extrasolar
planets around giant stars by the radial velocity technique and clarify the planet formation scenario around intermediate-mass stars.
In the East-Asian collaboration, in order to perform a large survey project we have conducted joint planet search programs using
2-m class telescopes in China, Korea, and Japan (east Asia). So
for, we have detected more than 40 planetary companions aroundintermediate-mass giant stars more massive than Sun in the project
and found several characteristic properties in the planetary systems
around intermediate-mass stars. In my talk, I report some planets
newly found by a Korean-Japanese planet search program in theframework of the EAPS-Net and their unique properties. Moreover,I would like to describe future stages of our collaboration using new
instruments dedicated for planet search projects.

2

Presenter: John Livingston (University of Tokyo)

Title
200 planets and candidates from K2’s second year
Abstract
We present ∼ two hundred candidates and planets discovered by
the NASA K2 mission during its second year. We statistically validate a large fraction of these systems based on our analysis of the K2
photometry, as well as intensive follow-up stellar spectroscopy andhigh resolution imaging, which also provide precise physical parameters for most systems. Of particular interest are planets with brighthost stars amenable to characterization, multi-planet systems, andsmall planets receiving Earth-like irradiation. By performing followup transit photometry from space with Spitzer, and from the groundwith MuSCAT, we also refine the ephemerides of these interesting
systems, which helps ensure the feasibility of future atmosphericstudies with JWST.

3

Presenter: NGUYEN Thi Phuong (Vietnam National Satellite Center )Title
GG Tau A: gas and dust inside the cavity, rings and gaps
Abstract
Exoplanet observations reveal that planets can form and survive around binary systems either in circumbinary or circumstellar
orbits. GG Tau A, a young hierarchical triplet TTauri system, (AaAb1/b2) with separations between of 35 and 4.5 au for Aa/Ab andAb1/Ab2 respectively, has been extensively studied. Recent analyses from CO isotopologues reveal that there may be a planet embryoin the circumbinary disk while inside the cavity the CO gas is resolved in several fragments. The kinematics of the system is mostly
Keplerian but departs from it inside the central cavity. New cycle 3
ALMA observations (ALMA# 2015.1.00224.S) at higher spatial resolution (0.15 arcsec) bring significant improvements to earlier studies and reveal apparent ”ring-gap” features in several tracers suchas 12CO(3-2), 13CO(3-2), C18O(3-2) and CS(7-6). The morphology and kinematics of the system as the physical properties of theouter disk as the CO clumps inside the cavity unveiled by these newobservations will be presented.

4

Presenter: Kohei Ichikawa (Columbia University/NAOJ)

Title
Is there a maximum mass for supermassive black holes?
Abstract
Recent quasar surveys have revealed that supermassive black
holes (SMBHs) rarely exceed a mass of MBH ∼ a few × 1010 Msun
during the entire cosmic history. It has been argued that quenching of the BH growth is caused by a transition of a nuclear accretion disk into an advection-dominated accretion flow, with whichstrong outflows and/or jets are likely to be associated. We investigate the relationship between the maximum mass of SMBHs andthe radio-loudness of quasars with a well-defined sample of ∼105
quasars at a redshift range of 0 < z < 2, obtained from the Sloan
Digital Sky Surveys DR7 catalog. We find that the number fraction of the radio-loud (RL) quasars increases above a threshold of
MBH ≃ 2 × 109 Msun , independent of their redshifts. Moreover, thenumber fraction of RL quasars with lower Eddington ratios (out of
all RL quasars), indicating lower accretion rates, increases above thecritical BH mass. These observational trends can be natural consequences of the proposed scenario of suppressing BH growth aroundthe apparent maximum mass of ∼ 1010 Msun . The ongoing VLASky Survey in radio will allow us to estimate of the exact number
fraction of RL quasars more precisely, which gives further insight
into the quenching processes for BH growth.

5Presenter: Andreas Schulze (NAOJ)

Title
New constraints on the black hole spin in radio-loud quasars
Abstract
One of the major unsolved questions on the understanding of
the AGN population is the origin of the dichotomy between radioquiet and radio-loud quasars. The most promising explanation isprovided by the spin paradigm, which suggests radio-loud quasars
to have higher black hole spin. However, the measurement of blackhole spin remains extremely challenging. We here present resultscomparing the mean radiative eﬃciencies of carefully matched samples of radio-loud and radio-quiet SDSS quasars at 0.3< z <0.8.
We find evidence for systematically larger radiative eﬃciencies by afactor >1.5 in the radio-loud sample, suggesting that the radio-loudquasar population has on average higher black hole spin that theradio-quiet population. This provides strong observational support
for the black hole spin paradigm.

6

Presenter: Minbae Kim (Kyung Hee university)

Title
The eﬀect of bar-driven gas inflow on the AGN triggering in SDSS
late-type galaxies
Abstract
We explore the role of bars in AGN activities using a volumelimited face-on disc galaxy sample with Mr < −19.5 and 0.02 < z <0.055 selected from SDSS DR7. In this study, we investigate how
the fraction of galaxies having strong bar is related to the amountof cold gas at galactic center (∼1 kpc scale) required for triggering AGN activity. To understand how directly the bar presence isrelated to triggering AGN activity, we measure a relative probability defined as the ratio of the probability of AGN triggering inbarred galaxies to the probability of the AGN triggering in a comparison, non-barred galaxies, for fixed central SFR (central gas fuel)and velocity dispersion of galaxies (black hole mass). We find thatbars are one of the mechanisms that trigger AGN, and the eﬀect
is pronounced in less massive and lasts even in galaxies with little
central gas. We also suggest a concentrated bulge as a morphologythat contributes to the AGN triggering although the eﬀect is not as
great as bars.

7

Presenter: Yu-Ting Wu (NAOJ/ASIAA)

Title
Time-dependent Pattern Speeds in Barred Galaxies
Abstract
In galactic dynamics, bars are usually assumed to be rigid rotating structures with constant pattern speed. We check these common assumptions with high quality N-body simulations of double
bar galaxy models. We investigate the characteristics of bars, including the size, strength and instantaneous pattern speed withthree distinct methods, and show that bars are actually flexible andsubstantially time-dependent structures due to the gravitational interaction with nearby structures, such as spirals, which rotate at
distinct speeds. We find that the characteristics of the inner bar
are mainly aﬀected according to the phase angle between the innerand outer bars. On the other hand, in the case of the outer bar,its characteristics are substantially influenced by the adjacent spiralstructure.

8

Presenter: Hoai Thi Do (Vietnam National Satellite Center)

Title
Study of the circumstellar envelopes of evolved stars
Abstract
We present observations made at the ALMA and IRAM Plateau
de Bure interferometers of the CO emission at millimetre/sub-millimetre
wavelengths of evolved stars. We model in space the morphology andkinematics of the gas envelopes using simplifying hypotheses suchas rotation invariance about an axis. Examples are presented that
illustrate the main results.

9

Presenter: Lixin Dai (Niels Bohr Institute)

Title
Probing super-Eddington accretion with tidal disruption events
Abstract
A star wandering too close to a massive black hole can be torn
apart by the tidal force of the black hole. Such a tidal disruption
event (TDE) illuminates a massive black hole for about a year. In
the first few months, stellar material can be supplied to the blackhole at a rate greatly exceeding the Eddington accretion rate. Therefore, TDEs can give us a chance to peek into super-Eddington accretion, which has important implications for black hole growth andgalaxy evolution in the early universe. In this talk, I will first givea summary of the observational status of tidal disruption events(TDEs). Then I will introduce the basics of TDE physics and present
our theoretical calculations on what are the key parameters leading
to super-Eddington TDEs. Lastly, I will talk about our 3D generalrelativistic radiation magnetohydrodynamics simulations of superEddington accretion disks in the context of TDEs. The results ofthese simulations provide us answers to some puzzles posed by TDE
observations, and can be applied to study other super-Eddington
astrophysical systems.

10

Presenter: Sarah Ann Bird (Shanghai Astronomical Observatory)

Title
VELOCITY DISPERSION AND MASS PROFILES OF THE
MILKY WAY’S HALO
Abstract
We analyze the line-of-sight velocities of several thousand halo Kgiant stars from the third data release of the spectral survey LAMOST. We make use of a new method to estimate the enclosed dark
halo mass of the Milky Way within 100 kpc from the Galactic Centerusing the velocities and distances of these K giants. We derive estimates for the virial radius and concentration parameter from our
mass profile, as well as estimate the circular (rotational) velocity
curve out to 100 kpc. Tens of thousands of such stars are expected
to become available to this analysis by the end of the five year survey.
We find a nearly constant line-of-sight velocity dispersion profile, nolarge dips or peaks, in a Galactocentric radial range of 10 to 30 kpc,
where such dips have been seen in other surveys.

11

Presenter: Youngsoo Jo (Korea Advanced Institute of Science and Technology)

Title
Far-ultraviolet fluorescent molecular hydrogen emission map of
the Milky Way Galaxy
Abstract
We present the far-ultraviolet (FUV) fluorescent molecular hydrogen (H2 ) emission map of the Milky Way Galaxy obtained with
FIMS/SPEAR covering 76% of the sky. The extinction-corrected
intensity of the fluorescent H2 emission has a strong linear correlation with the well-known tracers of the cold interstellar medium(ISM), including color excess E(B-V), neutral hydrogen column density N(H I), and Hα emission. The all-sky H2 column density map
was also obtained using a simple photodissociation region model andinterstellar radiation fields derived from UV star catalogs. We estimated the fraction of H2 (fH2 ) and the gas-to-dust ratio (GDR) of
the diﬀuse ISM. The fH2 gradually increases from <1% at opticallythin regions where E(B-V) < 0.1 to ∼50% for E(B-V) = 3. The
estimated GDR is 5.1×1021 atoms cm−2 mag−1 , in agreement withthe standard value of 5.8×1021 atoms cm−2 mag−1 .

12Presenter: Yuna Grace Kwon (Seoul National University)

Title
Optical and Near-Infrared Polarimetry in Cometary Science
Abstract
Comets are fossilized remnants of the formation epoch of the solar
system (approximately 4.6 Gyr ago), and most likely contain pristine
ice and dust particles deep inside their bodies. When they start toapproach the Sun, however, inside volatiles sublimate dragging dust
particles outward. Such dust particles scatter sunlight mainly in the
wavelengths between 0.7–2.3 µm. In this regard, linear polarizationof such cometary dust particles can be a useful tool to constrain
the physical properties, such as sizes, compositions, and porosities.
Here, we present our studies of optical and near-infrared polarimetry
to decipher the primitive information using ground-based telescopesthat constitute a portion of the Optical and Infrared Synergetic
Telescopes for Education and Research (OISTER) network in Japan.
We will report and discuss our observational results in terms ofevolutionary eﬀects in this presentation.

13

Presenter: Jeong-Eun Heo (Sejong University)

Title
MIKE Observations and Raman-scattering by Atomic Hydrogenin the Symbiotic Nova RR Telescopii
Abstract
We present a high-resolution optical spectrum of the symbiotic
nova RR Tel obtained with MIKE at Magellan-Clay telescope. RR
Tel is believed to be a wide binary system of a hot white dwarf anda Mira with an orbital period of a few decades, where the whitedwarf is accreting through gravitational capture of some fraction ofmaterial shed by the Mira. We find broad emission features formed
through Raman-scattering of far-UV O VI 1032, 1038, C II 1036,
1037 and He II 1025, 972, 949 Åby neutral hydrogen. In particular,
Raman O VI features exhibit clear double-peaked profile indicativeof an accretion flow with a characteristic speed ∼ 40 km/s. In
contrast, Raman C II features have a simple Gaussian profile ofspeed ∼ 20 km/s that is considerably smaller than O VI. We perform
a profile analysis of the Raman O VI and C II features by assumingthat O VI emission traces the accretion flow around the white dwarf
with a representative scale of 1 AU whereas C II is formed in a much
more extended region encompassing the two stars. An additional
photoionization calculation using ’CLOUDY’ is presented, whichappears consistent with our emission model based on our profile
analysis.

14

Presenter: Satoshi TAKESHIGE (Kyoto University)

Title
Cooling eﬀects of an optically-thin synchrotron radiation during
the Petschek-type magnetic reconnection process
Abstract
In recent studies, relativistic magnetic reconnection processes areinvestigated by relativistic resistive magnetohydrodynamic (RRMHD)
simulations. In the classical reconnection model, the inflow magnetic
energies are converted to the outflow thermal and kinetic energies ofoutflow plasmas. For relativistic plasmas in a strong magnetic field,
the synchrotron radiation has an important role for cooling plasmas.
In our study, we investigated eﬀects of the radiation cooling in the
Petscheck type reconnection process, using RRMHD simulations. In
our simulations, for simplicity, we assumed an optically-thin radiation and introduced a radiation cooling rate as source term. As aresult, we found that the reconnection outflow is more compressedand collimated.

15

Presenter: Dongyao ZHAO (KIAA Peking University)

Title
Exploring the Evolution of Brightest Cluster Galaxies since z ∼2
Abstract
BCG evolution is important for understanding the galaxy assembly history. My research has accomplished to provide new insights
into it since z ∼ 2. First my study worked on BCGs at z≤1 bycomparing properties between cD galaxies and elliptical BCGs. I
demonstrated that cDs are structural diﬀerent from elliptical BCGs,
mainly due to their unique envelopes. Moreover, cDs are larger andmore massive than elliptical BCGs, and prefer denser regions andmore massive haloes. Then I extended statistical study of BCG
evolution up to z ∼ 2. I developed a new method based on ranking
approach to select z ∼ 2 BCG progenitors. I found clear growthsof BCGs in size and stellar mass since z ∼ 2. Moreover, BCG progenitors are mainly late-type galaxies with disturbed morphologies
and higher SFR, while local BCGs are quiescent smooth early-typegalaxies. I demonstrated that at 1< z <2 SF and merging contributeequally to BCG growth. However, merging plays a dominant roleat z ≤ 1. My research completed an overall scenario for BCG evolution since z ∼2: over z=1–2, BCGs grow through both merging
and SF, which have equal contribution. After z ≤ 1, dry mergers
became dominant for BCG assembly, triggering the formation of cD
envelopes and driving transformation of elliptical BCGs into cDs.

16

Presenter: Tao Wang (University of Tokyo/NAOJ)

Title
Massive galaxy (trans)formation in the most distant X-ray cluster
at z=2.51
Abstract
Local galaxy clusters are exclusively dominated by massive, earlytype galaxies (ETGs) in their cores. While galaxy archaeology studies indicate that these ETGs are formed via intense starbursts on
short time-scales, direct observational evidence of this rapid formation of ETGs has been lacking. In this talk, I will present star formation and gas properties of a statistical sample of massive galaxies
in the most distant X-ray cluster discovered so far (z=2.51). Our
unprecedented data from HST, ALMA, and IRAM-NOEMA observations reveals that these massive galaxies tend to have higher starformation eﬃciency and shorter gas depletion time (∼0.3 Gyr) compared to field galaxies at the same redshift. This provides one of thefirst observational evidence of the rapid formation of massive ETGs
in galaxy clusters, providing new insights into the environmental
dependence of massive galaxy formation and evolution.

17

Presenter: Yu-Yen Chang (ASIAA)

Title
Structures of Submillimeter Galaxies by deep SCUBA-2 survey
at z=1-3
Abstract
It has been discussed that bright submillimeter galaxies (SMGs)
appear to have disturbed morphologies due to its short-lived nature.
Recently, a deep 450 um survey (STUDIES) of JCMT large program
allows us to explore intermediate bright SMGs. We investigate morphology of these SMGs at z=1-3 by HST/WFC3 H-band observationin the COSMOS-CANDELS region. We found that bright SMGs
( >7mJy) has a high fraction of disturbed features, which is consistent with previous findings. However, intermediate bright SMGs
( <7mJy) shows insignificant diﬀerence from normal galaxies at thesame stellar mass and redshift bin. Our results imply that intermediate bright SMGs can be similar to normal star-forming galaxies,
and quenching process by major merger may only related to bright
SMGs.

18

Presenter: Chen-Fatt Lim (Academia Sinica Institute of Astronomy and Astrophysics(ASIAA) & National Taiwan University (NTU))

Title
SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES): Number
Counts and Counterpart Properties
Abstract
We present an ultra deep 450µm cosmological survey, SCUBA2 Ultra Deep Imaging EAO Survey (STUDIES). STUDIES is a
JCMT Large Program, conducted with SCUBA-2 from December
2015. The goal is to understand the evolution of faint far-infrared
sources that comprise the bulk of the cosmic star formation at z ∼1 to 3. The STUDIES image is taken within the deep extragalactic
CANDELS-COSMOS survey footprint under the best submillimeter
weather on Maunakea. The total observing time of the observations
will be 330 hours. With the first-year data (∼137 hours), we reacha sensitivity of ∼ 0.91 mJy rms in the deepest region in our map
and cover an area of ∼ 150 arcmin2. A total of 98 and 141 sources
are identified at 4σ and 3.5σ, respectively. We also performed simulations of the 450µm image to derive the intrinsic source counts.
Thanks to the smaller beam size of JCMT at 450µm (∼7”), we canidentify the multi-wavelength counterparts to the 450µm sources,
and conduct SED fitting on the counterparts to estimate their photometric redshifts, infrared luminosities/star formation rates, dust
temperature, and stellar masses. We present the number counts,
counterparts, and the multi-wavelength properties of our 450µm
sample.

19

Day 2 (November 15)

Presenter: Nao Suzuki (Kavli IPMU / Univ of Tokyo)

Title
A Brief History and Future Prospects of Dark Energy
Abstract
It was in 1997, the discovery of “dark energy” was reported ata group meeting in Berkeley but everyone was very skeptical. I
will introduce how the discovery was made and some of the behindthe-scene stories I learned from the supernova cosmology project
team. After 20 years of discovery, we still do not know the nature ofdark energy. I will introduce and discuss ongoing supernova survey
with Hyper-Suprime Cam on Subaru Telescope and Hubble Space
Telescope as well as future projects.

21

Presenter: Kenneth Wong (National Astronomical Observatory of Japan)

Title
Cosmology from Gravitational Lens Time Delays
Abstract
Strong gravitational lens systems with time delays between themultiple images are a powerful probe of cosmology and astrophysics.
In particular, the time-delay distance from such a system is primarily sensitive to the Hubble constant (H0) that is key to probing darkenergy, neutrino physics, and the spatial curvature of the Universe,
as well as discovering new physics. The H0 Lenses In COSMOGRAIL’s Wellspring (H0LiCOW) project aims to measure H0 to
¡3.5

22

Presenter: Miftahul Hilmi (Institute for Cosmic Ray Research, the University ofTokyo)

Title
Calculation of the Lyman-Continuum Photons Production Eﬃciency ξ ion of z ∼ 3.8 – 4.7 Galaxies Based on the IRAC Hα Fluxes
Abstract
Cosmic reionization is the transition of neutral hydrogen in the
IGM into the ionized state that we observed today. This physicalprocess is driven by Lyman-Continuum photons. Some uncertainties
remain regarding the cosmic reionization, i.e. how was the mechanism and which source drives the reionization. In order to investigate the reionization sources, we need information about ionizing
photons emissivity, which can be determined by three parameters:
the Lyman-Continuum photon production eﬃciency ξion, escapefraction fesc, and UV luminosity density ρUV. In this work, we derive the first parameter in a similar way as Bouwens et al. 2016.
We use 259 spectroscopically confirmed dropout galaxies identified
in the ∼ 100deg2 Subaru HSC Survey (Ono et al. 2017) and select the data with z ∼3.8–5.0, where the Hα emission line falls into
the Spitzer/IRAC channel 1 band (3.6 µm). We use the ∼ 30deg2
Spitzer data, which is ∼ 40× larger than previous studies. We derive the Hα fluxes using the SED fitting method (Smit et al. 2016)
and estimate the value of log ξion = 25.14 ± 0.08. Based on the obtained ξion, we discuss what is the main contributor for the cosmic
reionization.

23

Presenter: Ryota Kawamata (The University of Tokyo)

Title
Size–luminosity relations and UV luminosity functions at z =6–
9 simultaneously derived from the complete Hubble Frontier Fields
data
Abstract
We construct z=6-7, 8, and 9 faint LBG samples with accurate
size measurements by profile fittings with the glafic software fromthe complete Hubble Frontier Fields data. These are the largest
samples hitherto and reach down to the faint ends of recently obtained deep luminosity functions. We find incompleteness eﬀects
that faint larger galaxies are overlooked are not ignorable and makethe modal size 1.6 times smaller at MUV = -16. We aim to simultaneously derive the size–luminosity (RL) relations and UV luminosity
functions (LF) with the completeness correction using the correct
statistics. Thus, we conduct the maximum-likelihood estimationsof the two-dimensional distributions on the RL plane. At z=6-7,
we find a steep slope of the RL relation of beta=0.46±0.1, despite
the completeness correction. This value is notably steeper thanbeta=0.25+0.15-0.14 at z=5 by Huang et al. This steepness canbe reproduced only by a simple analytical model, in which smaller
galaxies contain a smaller fraction of specific angular momentum.
Moreover, we find a shallow faint-end slope of the LF, alpha=1.86+0.17-0.18, which strongly correlates with the slope of the RL
relation.

24

Presenter: Alessandro Sonnenfeld (Kavli IPMU)

Title
Revisiting the stellar IMF - dark matter halo degeneracy in strong
lens galaxies
Abstract
Accurately determining the dark matter distribution in galaxies
is crucial for testing galaxy formation and cosmological models. Oneof the challenges we encounter when measuring dark matter masses
in galaxies is accounting for the contribution of the baryons to thetotal mass. This problem is particularly important in the centers ofmassive galaxies, where stars dominate the mass budget, and whereconverting from light to mass is made diﬃcult by uncertainties inthe stellar initial mass function (IMF). The degeneracy between thedark matter density profile and the stellar IMF can be partiallybroken by combining strong gravitational lensing, at few kpc scales,with weak lensing at larger scales. By jointly analyzing a sample of
60 strong lenses from the SLACS survey and 4,000 massive galaxies
with weak lensing data from CS82 we are able to simultaneously
constrain the halo mass and stellar IMF normalization of massive
galaxies. We find that in order to fit both datasets with the samemodel, the data requires the presence of steep mass-to-light ratio
gradients, which can be interpreted as gradients in the stellar IMF.

25

Presenter: Kuan-Chou Hou (ASIAA/NTU)

Title
Cosmological simulation with dust evolution
Abstract
Dust enrichment is one of the most important aspects in galaxy
evolution. The evolution of dust is tightly coupled with the nonlinear evolution of the ISM including star formation and stellar feedback, which drive the chemical enrichment in a galaxy. Numericalhydrodynamical simulation provides a powerful approach to studies
of such nonlinear processes.
In this work, we present a cosmological simulation using smoothed
particle hydrodynamics (SPH) with dust evolution. We consider
dust production in stellar ejecta, destruction in supernova shocks,
dust growth by accretion and coagulation, and dust disruption by
shattering for the processes driving the dust evolution. We also
treat the evolution of grain sizes distribution by representing theentire grain radius range by small (< 0.03 µm) and large (> 0.03µm) grains.
We show that our cosmological simulation allows us to examine
the dust mass function and to analyze the dust abundance and dust
properties in galaxies statistically. The redshift evolutions of dust in
galaxies are also examinable in the cosmological simulation. Basedon that, we could make some important predictions on the dust content in high-redshift galaxies to be tested by ALMA observations.

26

Presenter: Peter Scicluna (ASIAA)

Title
The Nearby Evolved Stars Survey: The Gas and Dust return to
the Galactic ISM
Abstract
The terminal mass-loss of low- and intermediate-mass stars on the
AGB dominates the return of mass to the local ISM. The Nearby
Evolved Stars Survey (NESS) is a project to observe the continuumand CO line emission from a volume-limited (d<2kpc) sample of 300
mass-losing AGB stars; our purpose is to systematically derive thepresent-day gas and dust mass-loss rates and the mass-loss historyof these objects, and is made possible by Gaia. We have a large
coherent observing strategy across multiple observatories, including
a JCMT large program. This will allow us, for the first time, todetermine the total gas mass return to the Solar Neighborhood,providing key constraints on AGB mass loss. The data will provide
the first direct measurement of a global dust-to-gas ratio for stellar
ejecta, and improve on existing determinations of the Galactic dust
production rate. The statistical power of the survey will provide
unique insights into mass return over a large parameter space. The
NESS project is a growing collaboration of the East Asian evolvedstars community in Taiwan, China, Japan, and Korea, as well as
collaborators in Europe and North America.

27

Presenter: Xiaohu Li (NAOC & ASIAA)

Title
A Special Molecular Factory in Space
Abstract
Understanding the origin and evolution of circumstellar and interstellar molecules is key to understanding the molecular universeand has become a fundamental goal of modern astrophysics. To
date, at least 50% of the interstellar species (in total around 200)
were detected in the circumstellar envelopes (CSEs) of the Asymptotic Giant Branch (AGB) stars, which are true “molecular factorie” in space. For long, The chemistry in the CSEs of S-type AGB
stars, which have a C/O ratio approximately unity and therefore
exhibit dual chemical features of both C-rich (C/O >1) and O-rich(C/O <1) stars, were poorly investigated. Recently, we have successfully conducted several observations towards the intrinsic S-typestar Chi Cyg, via the James Clerk Maxwell Telescope, the ALMA
Prototype 12-meter Telescope in Arizona Radio Observatory, the 10meter Submillimeter Telescope, and the Submillimeter Array. We
found that the CSE of Chi Cyg is the most special molecular factory
to date. In this talk, I will introduce our discoveries.

28

Presenter: Hyeseung Lee (chungnam national university)

Title
statistical study of turbulence from polarized synchrotron emission
Abstract
When turbulent motions perturb magnetic field lines and produce magnetic fluctuations, the perturbations leave imprints of turbulence statistics on magnetic field. Observation of synchrotron radiation is one of the easiest ways to study turbulent magnetic field.
Therefore, we study statistical properties of synchrotron polarization emitted from media with MHD turbulence. First, we obtainthe spatial spectrum and its derivative with respect to wavelengthof synchrotron polarization arising from both synchrotron radiation
and Faraday rotation. Second, we study quadrupole ratio to quantitatively describe the degree of anisotropy introduced by magnetic
field at multi-wavelengths. In this study, we demonstrate that the
spectrum and quadrupole ratio of synchrotron polarization can bevery informative tools to get detailed information about the statistical properties of MHD turbulence from radio observations of diﬀuse
synchrotron polarization.

29

Presenter: Tomoyasu Hayakawa (Department of astronomy, Kyoto University )Title
Supernovae Associated with Gamma-Ray Bursts: Disk Wind in
the Collapsar Model
Abstract
Since the first discovery on 1998, about twenty cases have been
established for a very energetic supernova associated with a GammaRay Burst (GRB-SN). They show diversities in their properties, origins of which are still under debate. A leading model for GRB-SNe
is the so-called collapsar model, i.e., a core collapse of highly rotating massive stars, in which a highly-collimated relativistic jet would
produce a GRB and a strong accretion-disk wind may trigger an
SN. However, no self-consistent model has been developed which
account for the mutual interaction between the collapsing envelope
and the outflows. In this study, we have constructed a simple collapsar model including the disk, the black hole and the envelope,taking into account the transport of mass and angular momentum
between these components and the action the outflows would haveon the collapsing envelope. We have found that the geometry of thedisk wind is a key to launch a GRB-SN. To explain main features of
the GRB-SNe, the collimation is necessary not only for the jet but
also for the disk wind. We show that some observational correlations
are explained by our models, controlled mainly by the diﬀerence inthe angular momentum within the progenitor star.

30

Presenter: Ryan, Wai Yan Leung (The University of Hong Kong)

Title
High Resolution Radio Imaging of the Pulsar Wind Nebula MSH
15-52
Abstract
Pulsar winds are relativistic charged particles accelerated by theextremely strong magnetic field of rotation-powered pulsars. In ayoung pulsar, these particles are moving much faster than the surrounding cold ejecta in an expanding supernova remnant (SNR).
Upon colliding with the ejecta, the pulsar winds are shocked and radiate broadband synchroton and inverse-Compton radiations. The
resulting structures are collectively known as pulsar wind nebulae(PWNe).
We present a high-resolution radio imaging study of the PWN
MSH 15-52 with new Australia Telescope Compact Array observations at 3 cm and 6 cm. The system is powered by a young ,energetic, and high magnetic field radio pulsar B1509-58. Previous
X-ray studies found a complex morphology for the PWN: the overall
shape resembles a hand, extending over 10 pc with small-scale features including a one-sided jet, pair of arc, filaments, and compact
emission knots in the associated HII region RCW 89.
Our new radio images show very diﬀerent morphology than the
X-ray counterpart. No radio emission was detected at the X-ray
jet position, instead, we found enhanced emission in a sheath surrounding the jet. We also discovered additional small-scale features
including a polarized linear filament next to the pulsar. Our polarization measurements show that the intrinsic orientation of magnetic
field aligns with the sheath and wraps around the edge of the jet.

31

Presenter: Shih-Ping Lai (National Tsing Hua University)

Title
Observations of magnetic fields in star-forming regions
Abstract
I can briefly review the main techniques and recent progress ofobservations of magnetic fields in molecular clouds.

32Presenter: Hao-Yuan Duan (National Tsing Hua University)

Title
Searching the First Hydrostatic Cores in the Perseus Molecular
Cloud
Abstract
First Hydrostatic Cores (FHCs) are the transient phase between
prestellar cores and Class 0 protostars. Therefore, FHCs are best
targets for understanding the earliest stage of star formation. Several FHCs candidates were suggested, but none of them have been
confirmed. Recently, some potential candidates of FHCs have beensuggested based on the low temperature from the SED fitting ( 10K30K); however, theoretical models predicted that FHCs can be heatedover 100K. The low temperature of FHCs derived from observation
may be due to the mixing of the unresolved FHCs and the cold envelope. In this project, we produce synthesis images using CASA
based on a simple self-similar collapse density model. We matchthe simulated images of First Core candidates in Perseus Molecular
Cloud to the SMA and VLA observational results. Our simulations
show that with both VLA and ALMA observations, we can decouple the FHC component from envelope with reasonable observing
time. The identification of FHCs will make great strides in our
understanding of star formation.

33

Presenter: Yoshiki Toba (ASIAA)

Title
Ionized Gas Outflows in Infrared-bright Dust-obscured Galaxies(DOGs) at 0 < z < 1
Abstract
We present the ionized gas properties of infrared (IR)-bright dustobscured galaxies (DOGs) that show an extreme optical/IR color, (i- [22])AB > 7.0, selected with the Sloan Digital Sky Survey (SDSS)
and Wide-field Infrared Survey Explorer (WISE). For 36 IR-bright
DOGs that show [OIII]5007 emission in the SDSS spectra, we performed a detailed spectral analysis to investigate their ionized gas
properties. In particular, we measured the velocity oﬀset (the velocity with respect to the systemic velocity measured from the stellar
absorption lines) and the velocity dispersion of the [OIII] line. We
found that the derived velocity oﬀset and dispersion of most IRbright DOGs are larger than those of Seyfert 2 galaxies (Sy2s) at
z < 0.3, meaning that the IR-bright DOGs show relatively strong
outflows compared to Sy2s. This can be explained by the diﬀerence of IR luminosity contributed from active galactic nucleus, LIR(AGN), because we found that (i) LIR (AGN) correlates with thevelocity oﬀset and dispersion of [OIII] and (ii) our IR-bright DOGs
sample has larger LIR (AGN) than Sy2s. Nevertheless, the fact that
28/36 ( 78 %) IR-bright DOGs have a large (> 300 km/s) velocity dispersion, which is a larger fraction compared to other AGN
populations, suggests that IR-bright DOGs are good laboratories
to investigate AGN feedback. The velocity oﬀset and dispersionof [OIII] and [NeIII]3869 are larger than those of [OII]3727, whichindicates that the highly ionized gas tends to show more stronger
outflows (Toba et al. 2017, ApJ, submitted).

34

Presenter: Dohyeong Kim (Seoul National University)

Title
What Makes Red Quasars Red?
Abstract
Red quasars are very red in optical through NIR (e.g., r’-K >5 mag and J-K > 1.3 mag in Urrutia et al. 2009). The red colors are possibly due to the dust extinction in their host galaxies,
and which are expected in a scenario where red quasars are an intermediate population between merger-driven star-forming galaxies
and normal unobscured type 1 quasars. However, the red colors canbe explained by alternative mechanisms of (i) an intrinsically red
continuum, (ii) an unusual high covering factor of the hot dust component (CF HD), and (iii) a moderate viewing angle, somewhere
between type 1 and type 2 quasars. In order to study the origin of
the red colors of red quasars, we use optical to NIR spectra of 20
red quasars at z ∼0.3 and 0.7. The LPb/LHb ratios of red quasars
are 10 times higher than unobscured type 1 quasars. Moreover,
the LPb/LHb ratios of 55% red quasars cannot be matched by any
physical conditions without adopting the concept of the dust extinction. The CF HD of red quasars are similar to that of unobscured
type 1 quasars. Furthermore, we find that the Eddington ratios of
red quasars are significantly higher than those of unobscured type 1
quasars. Consequently, these results strongly suggest the red colorsof red quasars arise from the dust extinction in their host galaxies,
as suggested in the merger-driven galaxy evolution scenario.

35

Day 3 (November 16)

Presenter: Woong-Tae Kim (Seoul National University)

Title
Nuclear Structures and Gas Accretion to Supermassive Black
Holes in Disk Galaxies.
Abstract
Disk galaxies, especially barred-spiral galaxies, abound with ringsand spirals in the nuclear regions. Nuclear rings exhibit star formation at a rate varying widely in the range of 0.1–10 Msun per year,
although what forms them remains uncertain. Nuclear spirals existing even in weakly barred galaxies are thought to channel gas
inflows to supermassive black holes residing at the centers. We use
high-resolution hydrodynamic simulations to study the formation of
nuclear rings and spirals in barred galaxies. We show that nuclear
rings form due to a centrifugal barrier rather than resonances, andthat star formation rates therein depend on the mass inflow rates
driven by the bar potential. We also show that nuclear spirals become nonlinear and shocked even for a very weak potential due to ageometric eﬀect. The shape of the spirals and shocks depends rather
sensitively on the background shear. The induced mass inflow rates
are enough to power black hole accretion in various types of Seyfert
galaxies.

37

Presenter: Scarlet Saez Elgueta (The University of Tokyo)

Title
Near infrared approach to the Line Asymmetry of Cepheids
Abstract
The Baade - Wesselink (BW) method used for determining distance to Cepheids is limited by the existence of the projection factor,
p, which is a numerical factor needed to convert the radial velocity
variations derived from spectral line profiles into photospheric pulsation velocity so that Vpuls= p Vrad. The asymmetry of the spectral line profile is aﬀected by phenomena related to the Cepheid’s
atmosphere such as velocity gradients, photospheric pulsation velocity (Vpuls), limb darkening, turbulence and rotation. They canbe all merged into the projection factor, p, therefore line asymmetry
should be understood as a source of information of all the phenomena involved in the Cepheid’s pulsation. This asymmetry depends
on how radial velocities are derived, i.e., either by bi-gaussian, line
minimum or centroid methods. Each of them yielding to diﬀerent
values of p and hence diﬀerent distances. One key idea of the BW isthat angular and linear diameters must correspond to the same layer
in the star to provide a correct estimate of the distance. Previous
works have combined IR interferometry with optical spectroscopy.
My work aims to overcome that diﬃculty by using high resolution
IR spectroscopy provided by WINERED for galactic Cepheids observed in the past years.

38

Presenter: Chien-Hsiu Lee (Subaru Telescope, NAOJ)

Title
Time-domain studies of M31
Abstract
M31, our closest neighboring galaxy, is a stepping stone to studies
of stellar evolution, star formation, galaxy evolution, and cosmology.
However, due to the diﬃculties of performing photometry in suchcrowded fields and the lack of wide cameras to encompass the entire
galaxy, there has not been a complete census of the stellar contentsof M31. The advent of wide-field camera provides us a unique opportunity to have a complete view of our neighboring galaxy, enablingan inventory of its variable content. I will present a review of recent progresses of wide-field, high cadence surveys of M31, covering
diﬀerent population of variables and transients. I will also outline
future studies enabled by ongoing and upcoming facilities.

39

Presenter: Atsushi Tanimoto (Kyoto University)

Title
Suzaku Observations of Compton-thick Active Galactic Nuclei
Selected by Swift/BAT Survey
Abstract
We present a uniform broadband X-ray (0.5–100 keV) spectral
analysis of 12 Swift/Burst Alert Telescope (BAT) selected Comptonthick (log(NH/cm2 ) > 24) Active Galactic Nuclei (CTAGNs) observed with Suzaku. We fit the Suzaku and Swift/BAT spectrawith an AGN torus model by Ikeda et al. (2009). The main results
are as follows. (1) Most of CTAGNs show small scattering fractions(<0.5%) implying a buried AGN nature. (2) Unabsorbed reflection
components are commonly observed, suggesting that the tori areclumpy. (3) Comparison with the results obtained for Comptonthin AGNs (Kawamuro et al. 2016) suggests that the propertiesof these CTAGNs can be understood as a smooth extension from
Compton-thin AGNs with heavier obscuration.

40

Presenter: Tien-Hao Hsieh (ASIAA)

Title
Probing Episodic Accretion in Very Low Luminosity Objects
Abstract
The bolometric luminosity of protostars is observed to be much
lower than expected from calculations under an assumption of constant mass accretion rates. Very Low Luminosity Objects (VeLLOs) present further puzzling properties that exacerbate this luminosity problem. Episodic accretion has been proposed as a solution,
whereby a protostar is at a quiescent accretion phase for most of thetime and has occasional accretion bursts delivering mass onto theprotostar. Due to the predicted interval between accretion bursts (∼5,000–50,000 yr), it is diﬃcult to directly measure the variation inaccretion rates. We present ALMA observations of N2H+ and CO
isotopologues to probe the episodic accre- tion process toward eight
VeLLOs using the CO snow line as a chemical signature. During theaccretion burst, the increasing luminosity elevates the gas and dust
temperature, evaporating CO to a much larger radius than that of
the quiescent phase. The gaseous CO destroys N2H+, pushing theperceived line further out. Because CO takes ∼ 10,000 yr to freezeout onto the dust grains at the densities in the envelope, it allows
us to probe a recent accretion burst by comparing the observed CO
sublimation radius to the expected radius from the current luminosity (< 200 au for our target VeLLOs with Lbol < 0.45Lsun). As
a result, out of the eight VeLLOs, five show evidence for the occurrence of a past burst, one has no recent accretion burst, and two areambiguous. This fraction (63% to 86%) of VeLLOs with accretion
burst signatures is similar or slighter larger than that of Class 0/I
young stellar objects from the literature, which inferred similar or
shorter interval between bursts in the episodic accretion process inthese objects.

41Day 4 (November 17)

Presenter: Jifeng Liu (National Astronomical Observatory of China)

Title
Multi-wavelength studies of stars in light of LAMOST
Abstract
LAMOST provides an unprecedently large sample of stars with
spectra, hence accurate spectral classification and stellar parameters. This enables studies of statistical behaviors of diﬀerent stars,
and also searches of exotic objects that deviate from the group statistics. We have combined LAMOST with multi-wavelength databaseto study stellar statistics and special objects, and here we report
our preliminary results.

43

Presenter: Haruka Kusakabe (The University of Tokyo)

Title
Star Formation Activity of Lyα emitters at z ∼ 2
Abstract
Lyα emitters (LAEs) are one of the representative populationof high-redshift low-mass galaxies, which are ”building blocks” ofpresent-day galaxies. Stellar population properties and dark matter
halo mass are key to tracing the mass growth history of galaxies
and constraining physical processes which control star formation.
However, even at z ∼ 2, previous work on stellar and dark matter
halo properties of LAEs suﬀer from statistical errors and cosmic
variance due to their small sample size 250 and small survey area
∼0.3 deg2 (Guaita et al. 2010; 2011). In this work, we obtain∼1250 LAEs at z ∼ 2 in four survey fields over 1 deg2 (Nakajima
et al. 2012). Their average dark matter halo mass and stellar mass
10
are estimated to be 4.0+5.1
Msun (b = 1.22+0.16−2.9 × 10−0.18 ) and 1.0 ±0.3 × 109 Msun derived from clustering analysis and SED fitting,respectively. Our LAEs lie slightly above an extrapolation of theaverage SHMR relation and have slightly high baryon (i.e., gas)
conversion eﬃciencies, though they are SFMS galaxies. We will
discuss physical origin of these LAEs.

44

Presenter: Ting-Wen Lan (Kavli IPMU, University of Tokyo)

Title
The physical properties of the cool circumgalactic gas probed by
the Sloan Digital Sky Survey
Abstract
Gas around galaxies, the circumgalactic medium (CGM), contains signatures of galactic feedback and gas accretion, which are
key mechanisms driving the evolution of galaxies. To better understand the mechanisms, one can investigate the physical propertiesof the CGM via its absorption features imprinted in the spectra ofbackground objects. In this talk, I will show that we can probe
the physical properties of the cool CGM by making use of 100,000
metal absorption line systems detected in the background quasar
spectra from the Sloan Digital Sky Survey. Our results reveal a newand puzzling picture of the CGM: it consists of millions of small
dense clouds with metallicity evolving significantly with redshifts
and reaching the solar value at redshift 1. These results support
the hypothesis that the gas clouds are originated from galaxies. Finally, I will show that the physical properties of the CGM are strong
constraints on the models of galaxy evolution.

45

Presenter: Taiki Kawamuro (NAOJ)

Title
AGN nuclear structure studied by X-ray spectral analysis, andthe relevance to the surrounding ionized gas
Abstract
We systematically analyzed 0.5–150 keV X-ray spectra of local(z < 0.1) 45 obscured (22 ≤ log NH < 24) AGNs observed with
Suzaku and Swift/BAT (TK+16). Our sample is from the least
biased Swift/BAT 70-month survey. We find that the [OIV] 25.89
um line to X-ray luminosity ratio is smaller in AGNs with lower soft
X-ray scattering fractions (fscat ). This suggests that it is diﬃcult
for AGNs buried in a torus to ionize the surrouding material.
Our NuSTAR, Chandra, and Gemini/GMOS observations of two
local (z ∼ 0.3) AGNs (SDSS J0113 and SDSS J1155; TK+17 submitted) may support the result. The X-ray spectra of SDSS J0113
reveal a highly obscured (log NH = 23.8) AGN with a low scatteredfraction (≲ 10%), likely buried in a torus with a narrow ionization cone. Our Gemini/GMOS spectroscopy consistently proves thecollimated bipolar ionized gas. Conversely, SDSS J1155 shows aweakly obscured AGN with log NH = 22.8 and fscat ∼ 1.2%, and theuniformly extended [OIII] emission.

46

Presenter: Cristian Eduard Rusu (Subaru Telescope)

Title
Subaru Telescope adaptive optics observations of gravitationallylensed quasars
Abstract
We conducted an adaptive optics observation campaign of 25
gravitationally lensed quasars from SDSS. I will briefly describe ouranalysis technique and selected results. These include characterizing for the first time quasar host galaxies without an a-priori known
point-spread function; demonstrating that for galaxies with an ellipticity of the mass profile ¿ 0.25, the mass profile is less ellipticalthat the light profile; and the discovery of a three-image, ”natural
coronagraph” lensed quasar. Details can be found in Rusu et al.
2016, MNRAS, 458, 2.

47

Presenter: Yongjung Kim (Seoul National University)

Title
Survey of High-redshift Quasars with IMS
Abstract
Over the last decade, hundreds of quasars have been discoveredat high redshift. However, most of them are biased toward luminous
ones (M1450 <-24 mag), implying that such a biased quasar sample, which cannot represent the entire population of high-redshiftquasars, is not enough to understand the properties of quasars in
the early universe. Based on the Infrared Medium-deep Survey(IMS), a moderately wide (120 square degree) deep (J∼23 AB mag)near-infrared (NIR) imaging survey, we have discovered more than
200 candidates for faint quasars with the archive optical imaging
data. The faint quasar candidates have been narrowed down to tensof highly promising ones by the medium band observations withSQUEAN. Until now, about 10 faint quasars at z ∼5 and 6 havebeen spectroscopically identified. The discovery of these quasars
suggests that the number of faint quasars may not be high enoughto fully account for the cosmic reionization. Furthermore, we obtaina deep NIR spectrum of one of the faint quasars for the first time.
This shows a very interesting result about its black hole mass andaccretion rate compared to the luminous ones.

48

Abstracts (Poster)Presenter: Abdul Jawad (COMSATS Institute of Information Technology Lahore
Pakistan)

Title
Thermal Fluctuations of Well-Known Black holes Via Entropy
Corrections
Abstract
We investigate the thermal fluctuations of well-known black holes
via entropy corrections. For this purpose, versatile study is being
made by developing various thermodynamic quantities such as entropy, specific heats, pressure, Gibb’s and Helmhotz free energies in
the present frameworks. We also discuss the stability of black holes
through ratio of heat capacities (γ), grand canonical and canonicalensembles. We also investigate the phase transition for the present
black holes.

50

Presenter: Chien-Chang Feng (Department of Astronomy, Graduate School of Science, The University of Tokyo.)

Title
Weak Supernovae Induced by the Gravitational Energy Loss in
the Black Hole Formation
Abstract
Simulations regarding weak explosion induced by gravitational
mass loss is presented, as well as the comparison with current observation of failed supernovae. While a massive non-rotating starcollapsing into a black hole, an explosion that is much weaker thana normal core collapse supernova will form instead of just nothing.
While the shock passing through the hydrogen envelope, energy ofthe shock transferred onto optical observable by hydrogen recombination. The properties of the shock and the mass, radius determine
the brightness and duration of the light curves of the explosion.
Several progenitor models with diﬀerent masses are tested as well
as diﬀerent values of reduced gravitational mass. The formation of
the shock and the radiation transfer are perfumed with FLASH and
SNEC. The results show that massive progenitor tends to result in
more powerful explosions but the outburst durations are shorter andvice versa. But for the explosion light curve, more energy gives abrighter light curve but shorten the duration. The mass and theradius of the outer hydrogen envelope also change the light curve.
These could be valuable when constrain the properties of observed
failed nova.

51

Presenter: Chin-Ping Hu (The University of Hong Kong)

Title
The Spectral Evolution of a Transient Ultraluminous X-ray Source
CXOU J235808.7-323403
Abstract
We report a systematic analysis of the timing and spectral behavior of CXOU J235808.7-323403 (hereafter P9), a transient ultraluminous X-ray source located in NGC 7793. Before 2014, the spectraof P9 obtained by Chandra and XMM-Newton were well describedby either a power law with a photon index of 2.2 or a multi-color
disk blackbody with an inner radius of 50 km and an inner disk
temperature of 0.7-0.9 keV. The corresponding luminosity varied
between 1E38 and 7E38 erg/s, well below the Eddington limit of astellar-mass black hole. These behaviors imply that P9 was a canonical black hole X-ray binary (BHXB) in the high/soft state. After
2014, the luminosity of P9 varied between 1E39 and 6E39 erg/s. We
suggest that P9 showed an ultraluminous outburst, which provided
an important connection between the canonical BHXB and ultraluminous X-ray sources. The spectral evolution of the ultraluminous
outburst can be explained by super-Eddington models. When theluminosity is slightly above the Eddington limit, the spectrum canbe described as a standard disk with a radius of 360 km plus a
power-law tail with a photon index of 1.6, indicating the presence ofa Comptonized corona near the black hole. On the other hand, thespectrum can be well fit with an advection-dominated disk where
the radial temperature profile is power-law distributed with an index
of p=0.6 and an inner temperature of 2 keV, suggesting the formation of a geometrically thick disk when the luminosity was near
maximum.

52

Presenter: Fayin Wang (Nanjing University)

Title
Self-organized criticality in Astrophysics
Abstract
In this talk, I will present some recent progress on self-organizedcriticality in astronomy.

53

Presenter: Hideaki Fujiwara (Subaru Telescope, National Astronomical Observatoryof Japan)

Title
Seasonal variation of radial brightness contrast of Saturn’s rings
viewed in mid-infrared by Subaru/COMICS
Abstract
To investigate the mid-infrared (MIR) characteristics of Saturn’srings, we collected and analyzed MIR high spatial resolution images of Saturn’s rings obtained in January 2008 and April 2005 withCOMICS mounted on Subaru Telescope, and investigated the spatial variation in the surface brightness of the rings in multiple bands
in the MIR. We also composed the spectral energy distributions(SEDs) of the C, B, and A rings and the Cassini Division, and estimated the temperatures of the rings from the SEDs assuming theoptical depths. We find that the C ring and the Cassini Divisionwere warmer than the B and A rings in 2008, which could be accounted for by their lower albedos, lower optical depths, and smaller
self-shadowing eﬀect. We also find that the C ring and the Cassini
Division were considerably brighter than the B and A rings in the
MIR in 2008 and the radial contrast of the ring brightness is theinverse of that in 2005, which is interpreted as a result of a seasonal
eﬀect with changing elevations of the sun and observer above thering plane.

54

Presenter: Hidekazu Hanayama (Ishigakijima Astronomical Observatory, NAOJ)

Title
Ishigakijima Astronomical Observatory and Murikabushi 105cm
Telescope
Abstract
The Ishigakijima Astronomical Observatory (IAO) is one of theresearch institutes of National Astronomical Observatory of Japan(NAOJ) located in the southwest corner of Japan. The location
is appropriate for the observation of objects near the ecliptic andcelestial equator. The Murikabushi 105-cm telescope is the largest
telescope in the Kyushu & Okinawa area. On the Cassegrain focus, MITSuME (Multicolor Imaging Telescopes for Survey and Monstrous Explosions) three-color simultaneous imaging system is mounted.
Observations of transient objects such as gamma-ray burst afterglows are performed with the domestic and international collaborations. Furthermore, observations of Solar System Objects are powerfully performed taking advantage of the location. In this meeting,
we talk about the observatory and telescope, and report the observational results in recent years.

55

Presenter: Hoai Thi Do (Vietnam National Satellite Center)

Title
Study of the circumstellar envelopes of evolved stars
Abstract
We present observations made at the ALMA and IRAM Plateau
de Bure interferometers of the CO emission at millimetre/sub-millimetre
wavelengths of evolved stars. We model in space the morphology andkinematics of the gas envelopes using simplifying hypotheses suchas rotation invariance about an axis. Examples are presented that
illustrate the main results.

56

Presenter: Iulia Teodora Simion (Shanghai Astronomical Observatory, CAS)

Title
The metallicity gradients of the Milky Way discs with APOGEE
and LAMOST
Abstract
I use a model for stellar labels identification based on Support
Vector Regression named SLAM, to derive improved stellar parameters for the LAMOST targets. SLAM is trained on the higher resolution (R = 22,500) APOGEE DR14 spectroscopic survey to deriveparameters for the lower resolution (R = 1,800) LAMOST DR4 survey. The SLAM results outperform the LAMOST pipeline results
enabling us to build the largest catalogue of Red Giant Branch stars
with 6 labels (log(g), Teﬀ, [Fe/H], [alpha/M], [C/M] and [N/M]) by
combining the two catalogues. I derive ages for the stars using theC/M and N/M abundances (Martig et al. 2016) and study their
metallicity distribution in the Galactic Disc.

57

Presenter: Jerome Pitogo de Leon (U. of Tokyo)

Title
Follow up transit observation of HAT-P-44 using MuSCATAbstract
TBA

58

Presenter: Jia-Wei Wang (National Tsing Hua University)

Title
Gas Kinematics within IC5146 filaments: Does Magnetic Fields
Regulate the Gas Dynamics
Abstract
Magnetic fields (B-field) have long been considered as the key
components that regulate star formation. Polarization observations
reveal that the B-field at 100–1 pc scale is often ordered and dynamically important (e.g. Heiles 2000). On the other hand, interferometric observations show that B-fields are often randomly alignedwith gas flows at ∼1000 AU scale (Hull et al. 2014). It is unclear
how the role of B-field changes at the intermediate scale. To reveal
the gas kinematic within the filamentary cloud IC5146 at ∼0.1–0.03
pc scale, we performed JCMT 13CO (3-2) line observations toward
the Hub-Filament System (HFS) and also use the previous 13CO (32) observations toward the Main Filament region done by Graham(2008). The orientations of the velocity gradient traced by 13CO
(3-2) derived at diﬀerent scales are compared to our optical/infrared
polarization measurements to investigate how the B-field impact thegas kinematics at ∼0.1–0.03 pc scale. Our results show that the velocity gradient within Main Filament is aligned with B-field at 0.1
pc scale, but turn to be randomly oriented at 0.03 pc scale. In
contrast, the velocity gradient in the HFS is randomly aligned with
B-field at 0.1–0.03 pc scale, probably dominated by the gravity.

59

Presenter: Jincheng Guo (Peking University)

Title
Metallicity Gradient of The Milky Way disk revealed by FGK
dwarfs from LAMOST DR4
Abstract
By carefully selecting eﬀective temperature, surface gravity andother parameters obtained from LAMOST DR4 spectra, we constructed a sample of nearly 1.5 million FGK dwarf disk stars. First
we divided this sample into Thin disk and Thick disk based on[Fe/H] and [Alpha/Fe]. Then we studied the radial, vertical metallicity gradient and metallicity trend in the rotational direction forthin disk and thick disk, respectively.

60

Presenter: Kiran Adhikari (Golden Gate International College/ NPSA-Nepal Physics
Students Association)

Title
THEORETICAL STUDY OF MAGNETIC FIELD GENERATION DUE TO PONDEROMOTIVE FORCE IN PLASMA
Abstract
In this dissertation work the phenomenon of ponderomotive force
and laser interaction in plasma have been studied. For this, we startfrom the general expression for the force density (i.e the equation of
the motion ) of plasma in the electromagnetic field have been derived
on the basis of Maxwell equation. The equation of the motion is
deduced not only from the ponderomotive force but also from thetheory of two fluid model. We take ν = 0 (collisionless plasma)
because the relation of the equation which is valid when the fast
oscillation properties are neglected .
The complete equation of the motion can be deduced from thebasic equation of the continuum mechanics in relativistic formulation used in the well known theory of radiation frequencies. In thepresence of intense laser light, plasma particle are entrained by thefields of light and hence induced current, which in turn generatemagnetic field. The recent work shows that larger order of mega
gauss magnetic field is governed by scale length and intensity oflight used. From this work we had seen that ponderomotive force
arise due to the interaction of drifting electrons produced by theelectric vector of the wave with magnetic vector B of the wave anddue to the gradient of the drift velocity. For the theoretical calculation of B field in plasma we have taken exponential variation inelectron density along the axial direction and the Gaussian pulse
which has intensity distribution along the radial direction only.

61

Presenter: Kohei Mizukubo (Kagoshima University)

Title
Astrometry of the Galactic star-forming region IRAS 05358+3543
with VERA
Abstract
We performed astrometric observations of IRAS 05358+3543 with
VERA (VLBI Exploration of Radio Astrometry) at 22 GHz utilizing its H2O maser emission. The annual parallax was determined tobe 1.155±0.068 mas, corresponding to a distance of 0.86±0.05 kpc.
On the other hand, the previous astrometry with the Very Long
Baseline Array (VLBA) yielded an alternative distance of 1.68 kpc
utilising the 6.7 GHz methanol maser transition. This paper contribution aims to resolve the ambiguity between the VERA and VLBA
estimates of the trigonometric distance.

62

Presenter: Kris Akira Stern (The University of Hong Kong (HKU))

Title
TBC
Abstract
TBC

63

Presenter: Li Wen Liao (National Tsing Hua University)

Title
Reveiling the Compact Molecular Jets in the NGC 2023 MM1
Outflows
Abstract
NGC 2023 MM1, a class 0 protostar in Orion (d ∼ 460 pc), withL ∼ 7 L⊙ drives a large bipolar outflow in the CO (3-2) emission
previously observed with JCMT. Using the SMA, we resolved threecontinuum sources with an angular resolution of 3”. We also derived
masses of 4.3 M⊙ , 0.7M⊙ and 0.4 M⊙ for MM1, MM2 and MM3,
respectively. With an angular resolution of 4” and a spectral resolution of 1.2 km/s, we discover the compact jet components in both
the CO (2-1) and SiO (5-4) emissions. In the CO (2-1) emission, weshow a bipolar outflow with clear cavity in low velocity gas. Both
the CO (2-1) and the SiO (5-4) emissions show large velocity distributions in their PV-diagram. We also resolved the SiO (5-4) jets
and CO (2-1) outflows into knotty structures. We further studied
the kinematic of the innermost knots of SiO (5-4) jets and foundsome indications of jet rotation.

64

Presenter: Madoka Ohyama (Kagoshima University)

Title
Astrometric observations of protoplanetary nebula OH231.8+4.2
with VERA
Abstract
We report the results of annual parallax measurement of H2O
masers associate with OH231.8+4.2. This source is a protoplanetary nebula, located adjacent to the open cluster M46. In the large
scale, fast bipolar outflows with velocity of 200-400km/s was foundin 6”×57” scale (Morris et al. 1987, Snchez et al. 2015). The central
star is a Mira-like variable AGB star showing H2O and SiO maser
emission (Desmurs et al. 2007). However, there is still uncertinly inthe distance of OH231.8+4.2. To inspect accurate physical parameter, it is necessary to obtain highly-precise distance.
Using Japanese VLBI array “VERA”, we have observed H2O
maser in OH231.8+4.2 for 3 years with 1 month interval. An annual
parallax of π=0.61±0.03 mas was determined and it gives a corresponding distance of D=1.65(+0.08/− 0.07)kpc. In addition, propermotion of OH231.8+4.2 was determined to be µ=(-4.54±0.18, 0.92±0.18)mas/yr. H2O maser spots were distributed within 80
mas square, corresponding to 140 au at source distance. We subtracted the average motion from some maser spots, and estimatedtheir relative motion. This motion represents bipolar outflow fromthe central star with velocity of about 10km/s. We found that thisvelocity was quite slower than that was found in the large scale
outflows.

65

Presenter: Mikito Kohno (Nagoya University)

Title
FOREST Unbiased Galactic plane Imaging survey with the Nobeyama
45-m telescope (FUGIN) : Molecular clouds toward W33 ; possible
evidence for cloud-cloud collision triggering O star formation
Abstract
We observed molecular clouds in W33 high-mass star-forming region associated with compact and extended HII regions using the
NANTEN2 and Nobeyama 45-m telescopes in the J=1-0 transitionsof 12CO, 13CO, and C18O as a part of the FUGIN (FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope) legacy survey. We detected three velocity components at 35km/s, 45 km/s, and 58 km/s. The 35 km/s and 58 km/s clouds
are likely to be physically associated with W33 because of the enhanced 12CO J= 3-2 to J=1-0 intensity ratio as R(3-2/1-0) > 0.8
due to the ultraviolet irradiation by OB stars, and morphologicalcorrespondence between the distributions of molecular gas and theinfrared and radio continuum emissions excited by high-mass stars.
The two clouds show complementary distributions around the extended HII region (G012.745-00.153). The velocity separation is toolarge to be gravitationally bound, and yet not explained by expanding motion by stellar feedback. We discuss that cloud-cloud collision
scenario likely explains the high-mass star formation in W33

66

Presenter: Minhee Hyun (Seoul National University)

Title
Newly discovered large-scale structures in ELAIS-N1 field
Abstract
Large-scale structure (LSS) is a useful cosmic laboratory to study
the cosmic structure evolution and the eﬀect of environment ongalaxies, one of the hot issues of modern astronomy. In this talk,we will present the newly discovered galaxy clusters at z ≳ 1 and a
LSS spanning over 100 Mpc at z ∼ 0.9 in ELAIS-N1 field which isone of the Infrared Medium-deep Survey(IMS) fields. With multiwavelength data from the Pan-STARRS (g, r, i, z, y bands), HSC(g, r, i, z, Y bands), CFHT (z band), IMS (J band), UKIDSS DXS(J and K bands) and SWIRE (4 IRAC bands), we found new galaxy
cluster candidates at 0.2 < z < 1.6. Among them, we discovered
unusual and interesting galaxy cluster candidates showing high starformation activity at z ≳ 1. These cluster candidates show distinct
galaxy population from the local counterparts. Furthermore, a LSS
spanning over 100 Mpc in co-moving scale around the confirmed
supercluster of Swinbank et al. (2007) was revealed at z ∼ 0.9.
Interestingly, the newly discovered structure is more massive andlarger than the Swinbank supercluster.

67

Presenter: Na-Eun Shin (Seoul National University)

Title
Spectrum analysis and comparison between isolated galaxies andhigh- density environment galaxies
Abstract
This study compares the age distribution of stars in diﬀerent environments. Heavy and bright elliptical galaxies are classified into
high-density galaxies in the center of galaxy clusters and isolated
galaxies outside of the galaxy clusters. In the Sloan Digital Sky
Survey Data Release 7 data, that indexes related to the shape ofthe galaxy and the environment of the galaxy are calculated, twogroups are classified according to an absolute magnitude and thesurrounding galaxy density. The classified isolated galaxies are compared with two isolated galaxy catalogs (M. Argudo et al. (2015),
Khim et al. (2016)). The STARLIGHT program, which analyzes
the galaxy spectrum, was used to analyze the spectra of isolated
galaxies and galaxies in high-density environments. This investigated the age distribution of stars in each galaxy. As a result, themore isolated the galaxy is, the higher the rate of stars with theage between 108.5 yr to 109.5 yr. It means that the isolated galaxies
have a higher proportion of young stars than the galaxies in thehigh-density environment due to the merging of galaxies with thestar formation. Also, for the isolated galaxies, the evolution slowly
occurs during the merging process.

68Presenter: Ngan Kim Nguyen (Hokkaido University)

Title
The impact of galactic environment on star-forming clouds
Abstract
We explore the eﬀect of diﬀerent galactic environments on theproperties of star-forming clouds through variations in the background potential in a set of isolated galaxy simulations. Rising,falling and flat rotation curves expected in halo dominated, discdominated and Milky Way-like galaxies were considered, with andwithout an additional two-arm spiral potential. The evolution ofeach disc displayed notable diﬀerences that are attributed to different regimes of stability, determined by shear and gravitational
collapse. The properties of a typical cloud were unaﬀected by thechanges in rotation curve, but the production of small and large
cloud associations were strongly dependent on this environment.
This suggests that while diﬀering rotation curves can influence whereclouds are initially formed, the average bulk properties are eﬀectively independent of the global environment. The addition of aspiral perturbation made the greatest diﬀerence to cloud properties, successfully sweeping the gas into larger, seemingly unbound,extended structures and creating large arm - interarm contrasts.

69

Presenter: Pou-Ieng Cheong (NTHU)

Title
ALMA Observations of Spiral Accretion Flows Towards Extremely
Young Protostars
Abstract
Studying the accretion flows toward extremely young protostars
is an important step for understanding how the protostars and theprotoplanetary disks are assembled in the early stage of star formation. The accretion flows are commonly seen in the MHD numerical simulations; however, it is rarely observed toward young
protostars. Here we present our ALMA observations of the accretion flows around the extremely young protostar VLA1623A with a
Keplerian disk likely just formed (Murillo, Lai, et al. 2013). “Dendrogram” algorithm (Goodman et al. 2009) are used to identify theaccretion flows, and we find the three brightest “branches” and theirassociated “leaves” likely correspond to the spiral structure flowing
toward the central young cluster. We further compare the threeaccretion flows in the position-position-velocity cube to the CMU
model (Ulrich 1976; Cassen & Moosman 1981) which describe thevelocity structure of the gas accreting to the central protostar withconstant angular momentum. We find that our identified branch
structures well match with the CMU model.

70

Presenter: Sheng-Jun Lin (National Tsing Hua University)

Title
Dating a prestellar core: L1512
Abstract
We estimate the age of a prestellar core, L1512, in the Taurus
molecular cloud with H2D+ (110-111) and multiple transitions of
N2H+, N2D+ and DCO+ using GBT, JCMT, and IRAM 30 m
telescope. L1512 is chosen because it is globular-shaped and relatively isolated in the Taurus molecular cloud, providing an ideal
environment for studying the target properties. Prestellar cores are
the sites for future star and planet formation. Although we know thegravitational collapse plays a main role during the star formation,
it is not yet well understood how the detailed formation processdepends on the physical and chemical properties. One key factor
hindering our understanding is that it is quite diﬃcult to determine
the age of the prestellar cores. In order to estimate the age of theprestellar cores, we have developed two techniques: either measure
the deuteration ratio profile of a H-carrier (best species is N2H+) or
measure the depletion profile of CO, both across the core. With thehelp of chemico-dynamical models, we can compare the observations
to an evolutionary model for both methods and constrain the age ofthe cores.

71

Presenter: SUNGYONG HWANG (Seoul national university)

Title
TBA
Abstract
TBA

72

Presenter: Taichi Uyama (the University of Tokyo)

Title
Search for Exoplanets around Young Stellar Objects
Abstract
Young Stellar Objects (YSOs) often have protoplanetary disks
where planets are being formed. Some protoplanetary disks havebeen reported to have asymmetric features that imply planet formation. Detecting/constraining protoplanets can help discuss planet
formation mechanism. Here we will introduce near-infrared direct
imaging observations and present our results and discussions.

73

Presenter: Taku Okamura (University of Tokyo)

Title
Angular momentum evolution of disk galaxies at high redshift
Abstract
The stellar disk size of a galaxy depends on the fraction of thedark halo mass (Mdh) settled as disk stellar mass (M*), m* equiv
M*/Mdh, and the fraction of the dark halo angular momentum(Jdh) transferred to the stellar disk angular momentum (J*), j*equiv J*/Jdh. Since m* and j* are determined in a diﬀerent manner by a series of star-formation related mechanisms such as inflows
and feedbacks, measuring m* and j* at high redshifts is essential tounderstand the formation history of disk galaxies. We use the 3DHST GOODS-S, COSMOS, and AEGIS imaging data and photo-z
catalogs to examine m* and j* for star-forming galaxies at z ∼ 2,
3, and 4 when disks are actively forming. We find that the j*/m*
ratio is ∼0.77+-0.06 for all three redshifts over the entire mass range
examined, 8 * 1010 < Mdh/h−1 Msun < 2 * 1012 , with a possible(<30%) decrease with mass. This high ratio is close to those of
local disk galaxies, implying a nearly constant j*/m* over the past
12 Gyr, but a factor of a few higher than predicted (at z ∼ 2) byrecent theoretical galaxy formation simulations.

74

Presenter: Tamaoki Shohei (Nagoya City University)

Title
Near-IR imaging polarimetry toward RCW 106
Abstract
We carried out near-IR imaging polarimetry toward RCW 106
with the IRSF 1.4m telescope at SAAO and the imaging polarimetry SIRPOL on 2017 March and May. We have observed 24 fields
and mostly covered the southern part of the giant molecular cloud
associated with RCW 106, which is located at a distance 3.6 kpc
and is elongated approximately North-South direction with a sizeof 70x15 pc. Our preliminary analysis indicates that the global
magnetic field seems to run along the cloud elongation, unlike many
filamentary clouds that are often reported to have their elongations
perpendicular to the magnetic fields. Near the central part of RCW
106, the magnetic field appears to be influenced by the expansionof this HII region. Here, we present our preliminary results by comparing with the archival molecular line and far- to mid-IR data.

75

Presenter: Tamir Baatarjav (Graduate student in the Space Science Laboratory)

Title
Astronomical heritage activity in Mongolia
Abstract
Understanding the relation between human and nature is important for protection environment. Since the sky belongs to us all
and forms a whole with the environment perceived by human. As
Mongolia is one of the country with natural heritage. This abstract
about activities which have done in Mongolia for astronomical heritage. Through these activities we tried to improve universe awareness for public. Especially nomadic people participated in these
activities.We would like to share our activities and experience astronomical heritage in diﬀerent region.

76

Presenter: Teppei Minoda (Nagoya University)

Title
Thermal Sunyaev-Zel’dovich eﬀect in the intergalactic medium
with primordial magnetic fields
Abstract
According to many previous observations, magnetic fields arefound on various astronomical objects in the universe, from asteroids
to clusters of galaxies. One possible origin of these cosmic magnetic
fields is the magnetogenesis in the primordial universe. Magnetic
fields generated by such a cosmological mechanism are called primordial magnetic fields (PMFs), and are considered to aﬀect theevolution of matter density fluctuations due to the Lorentz force
and the thermal history of the IGM gas due to the so-called ambipolar diﬀusion. Hence the information of PMFs is expected to be
imprinted on the anisotropies of the cosmic microwave backgroundthrough the thermal Sunyaev-Zel’dovich (tSZ) eﬀect in the IGM. In
this talk, given an initial power spectrum of PMFs, we show dynamical and thermal evolutions of the IGM with PMFs, and computethe resultant tSZ angular power spectrum. As a result, we find thatthe tSZ angular power spectrum induced by the PMFs becomes
more remarkable on small scales than that by galaxy clusters evenwith PMFs below the current cosmological constraint (Minoda etal., 2017, arXiv:1705.10054). The measurement of the tSZ angularpower spectrum on small scales can provide the stringent constraint
on PMFs.

77

Presenter: Toshiyuki TANAKA (Cosmology Group, Graduate School of Science, Nagoya
University)

Title
21-cm Signal Originating within The Vicinity of The First Stars
Abstract
The first stars are the first luminous objects in the universe, whichmarked the end of the dark ages. They are thought to have aﬀectedfollowing structure formation. However, their properties have notbeen clarified very much, and there are still many theoretical models. Some characteristics, for example mass spectrum, can be investigated through observations of 21-cm line emitted from the vicinityof the first stars. The signals would be detected by forthcoming
radio interferometers such as the Square Kilometre Array (SKA).
In order to extract information regarding the properties, we needknowledge of the relation between the properties and the emerging
21-cm signals.
In this work, we conduct radiative hydrodynamics simulations,in which radiative feedback on gas dynamics and gas density profile are appropriately considered, to elucidate dependences of theemerging signals on the stellar mass and redshift. In this talk, wewill discuss the impact of the radiative feedback on the signal andits detectability with the SKA. We will also discuss expected signals
around remnants of the first stars.

78

Presenter: Tzu-Hsiang Chao (NTU Institute of Astrophysics)

Title
3D-Shearing-Box Simulation with Adaptive Mesh Refinement andGPU Acceleration.
Abstract
In this work, we describe the implementation of the shearing
box approximation with the GAMER (GPU-Accelerated AdaptiveMEsh Refinement ) MHD (Magnetohydrodynamics) code for studiesof accretion disks . The CPU (Central Process Units)-GPU (Graphic
Process Units) hybrid computation, a major feature of GAMER, canideally make performances more than ten times faster than CPUsbased computation. Since MRI (Magnetorotational Instability) in
the weakly magnetize disk is highly dependent on the resolution ofsimulations, the key feature we introduce here is the realization of
the AMR (Adaptive Mesh Refinement) scheme in a shearing box.
The AMR scheme can eﬃciently enhance the resolution on crucial
structures in small regions while not to increase the computation
cost. Two techniques introduced in the Athena code (James M.
Stone, 2010), the Crank-Nicholson update for the energy conservation of pure HYDRO cases and the orbital advection (FARGO)
for more eﬃcient and accurate calculation, are also implemented
in my code. Diﬃculties and resolution of implementing the above
two techniques to fit the AMR scheme and GPU structure will be
discussed. Results compared with previous works and performance
tests are also presented.

79

Presenter: Urago Riku (Kagoshima University)

Title
The spiral arm structures of the Milky Way galaxy revealed using
the longer period Mira variables
Abstract
Mira variables with long pulsation periods (log P > 2.7) arethought to be a young (∼100Myr) population and could be good
tracers of the spiral arm structures of our galaxy. We have monitored the long period Mira candidates selected from the IIIa, IIIb
regions in the IRAS 2-colors diagram in the near-infrared K band
since 2004. We determined the pulsation periods and amplitudes
and the mean magnitudes of 138 Miras. We also obtained the distance to them using the Period-Luminosity relation (PLR) of Miras.
The K band PLR has the large scatter at the longer period (log P> 2.4) due to the circumstellar extinction and we constructed the
3.4um PLR using the WISE 3.4um data, which has tighter correlation than the K band. We compared their galactic face-on positions
to the arm structures in the literatures and suggest that the longer
period Mira variables trace the arm structures.

80Presenter: Wen-Ping Lo (Institute of Astronomy & Astrophysics, Academia Sinica/National
Taiwan University)

Title
Constraints on the Mass Accretion Rate of Cygnus A with Submillimeter Array
Abstract
How the mass accretion rate of SuperMassive Black Holes (SMBHs)
is related to the gas feeding from the larger spatial scales, and how
it is related to the energetic jet/outflow activities, are fundamental questions for the understandings of the active galactic nuclei(AGN). Faraday Rotation Measure (RM), the tracer of electron column density and magnetic field strength along the line of sight, is
one of the powerful method to constrain the mass accretion rate at
the vicinity of SMBH. We present the polarimetric results on thecore emissions of Cygnus A utilizing Sub Millimeter Array (SMA)at millimeter wavelengths and derive the constraints on the Faraday
rotation measure. There is no statistically significant detection of
the polarized emissions from Cygnus A. Low fractional polarization
at 230 GHz is presumably due to variating Faraday RM screen since
the high percentage of polarization (12 %) have been detected with
mid-Infrared observations. With the scenarios of beam and bandwidth depolarizations from the accretion flow, the mass accretion
rate and the accretion power can be constrained, and convectiondominated accretion flow solution can be ruled out.

81Presenter: Yao Lu (Purple Mountain Observatory, Chinese Academy of Sciences)

Title
SPACE DEBRIS DETECTION AND CHARACTERIZATIONUSING CNEOST SURVEY DATABASE
Abstract
The China Near Earth Object Survey Telescope (CNEOST), located at the Xuyi station of the Purple Mountain Observatory, wasbuilt with the first aim to detect Near Earth Asteroids and Comets,
equipped with a 1.20 meter primary mirror and a 1.04 meter corrector and a 10K × 10K CCD camera corresponding 1.94◦ ×1.94◦ FOV.
A sky survey has been carried out since 2009, in which 60 seconds exposures was adopted mostly. Inevitably, space debris streaks would
appear on these images, therefore an experiment of space debris detection and characterization has been conducted utilizing CNEOST
survey database.
In this preliminary work, only near GEO objects are considered.
Firstly, a morphological algorithm has been developed to detect
the possible debris streaks on pre-processed images. Then candidate streaks are extracted and examined by several criteria such as
streak profile i.e. streaks length and orientation of near GEO objects
should be close to 15 arc-minutes along east-west direction within 60
seconds exposures. Finally some analysis have been done to characterize their rotational motion according to the light curves extracted
from streaks. In a word, the utility of astronomical time-domain surveys database for space debris data mining has been demonstrated
in this paper.

82

Presenter: Yosuke Furuya (Yamaguchi university)

Title
Investigation of radio structures of high-z quasars by VLBI observations
Abstract
The purpose of our observations is to increase the number of
VLBI image of high redshift quasars. Recently, there are only 61
objects observed by VLBI at redshift z > 3, which is statistically
insuﬃcient for discussions of the process of AGN formation. Therefore, we observed nine quasars at redshift z > 4 with JVN (Japanese
VLBI Network) at 8.4 GHz and attempted to obtain the VLBI images. As a result, we succeeded to obtain the VLBI images for fivesources. The VLBI images show there five sources have really compact structure of less than 10 mas and high brightness temperatureof more than 108 K. In order to increase VLBI images eﬀectively,
we will carry out two type of observations . Firstly, we will observe
sources selected by new criterium with JVN. This observation will
be performed to check whether there sources can be detected or notwith VLBI. We expect to increase the number of sources detectedby VLBI. Secondly, we will observe the sources detected by JVN observation with EAVN (East Asia VLBI Network), in order to obtain
more detailed VLBI images.

83