Name | Talk Title & Abstract |
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Wen Ping Chen | Hunting for Substellar Objects Young and Old Rich and Poor |
With insufficient mass to sustain core hydrogen fusion, substellar objects continue to cool and fade in brightness after birth. Those heavier than abut 13 Jupiter masses, called brown dwarfs, manage to ignite deuterium or lithium, thereby maintaining hydrostatic equilibrium for a short period of time. Those less massive than this do not undertake any nuclear reaction whatsoever in their lives and evolve like planets. So far a few thousand brown dwarfs and planetary-mass objects are known, almost exclusively in the solar neighborhood, i.e., they are already aged. Characterization of the youngest substellar objects by spectroscopy is hampered by their faintness and often confusion with field contamination. (1) We describe our effort to identify substellar candidates in nearby star-forming regions 1 to 2 Myr old, the era when brown dwarfs are being formed or in their infancy. Our sample of substellar populations in star clusters of known ages and distances provides stringent constraints on theoretical modeling of ultracool atmospheres, and of chromospheric/coronal activity. (2) We also present how these least-massive members as being the most vulnerable in stellar dynamics to get ejected, leading to eventual disintegration of star clusters. Finally, (3) we report the discovery of metal-poor brown dwarfs away from the disk.
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Jianning Fu | LAMOST observations for the Kepler fields and LAMOST Medium-resolution Spectroscopic Survey Plan |
As an innovative astronomical telescope with large aperture and large field of view, LAMOST has the highest spectral acquisition rate in the world. Kepler Space Telescope is a high-precision continuous photometric satellite launched by NASA, whose main scientific objective is to detect exoplanets. The presentation will first introduce the spectroscopic observations of LAMOST for the Kepler fields, as well as the scientific research and important achievements based on the data. The speaker will then describe the performance of LAMOST medium resolution spectrographs, summarize the test results, and elaborate the survey plan. Finally, the great potential and prospect of LAMOST Medium resolution spectroscopic Survey in the study of the Galaxy and stellar physics will be looked ahead.
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Kyle Finner | $MC^2$: Reconstructing the Merger Scenario for Massive Galaxy Clusters with Subaru Weak Lensing |
Galaxy clusters are the largest particle accelerators in the universe as highlighted by the numerous emissions that arise from their intracluster media such as radio relics, radio halos, and X-ray bremsstrahlung. Of these phenomena, the diffuse radio emission from relics and halos have been connected to galaxy clusters that have recently undergone merging activity. Heightening the importance of galaxy clusters as astrophysical probes is the dominance of their mass by dark matter. The Merging Cluster Collaboration ($MC^2$) has selected a sample of merging galaxy clusters with observed radio relics to investigate the formation of radio emission and the nature of dark matter. Equipped with deep Subaru Suprime-Cam imaging, the $MC^2$ team is mapping the dark matter distributions of these clusters with weak lensing. Supplementing the Subaru data with Keck and MMT spectroscopic classification of cluster members and Chandra and XMM Newton observations of the hot X-ray emitting ICM, we are reconstructing the merger scenarios that lead to the generation of the radio relics. I will present an introduction to the $MC^2$ data set and recent results stemming from our investigation. I will especially focus on one of the most massive clusters in the universe, PLCKG287.0+32.9, with its double radio relics and on a perplexing off-axis collision in Abell 115.
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Paul Ho | EAO Prospectives |
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Tien-Hao Hsieh | |
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Ho Seong Hwang | Redshift Surveys of Galaxy Clusters with Weak-lensing Maps |
Galaxy clusters, the largest gravitationally bound systems in the universe, are important astrophysical laboratories for testing structure formation models. I will present the results from galaxy redshift surveys in and around galaxy clusters of which weak-lensing maps are available, and discuss the prospects for the redshift surveys of galaxy clusters with the Subaru telescope.
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Narae Hwang | Korean 8m Class Optical Facility: Gemini Observatory |
As of July 24th 2018, Korea Astronomy and Space Science Institute (KASI) has entered into a formal partnership with the Gemini Observatory. Effective from the 2019A Call for Proposals (CfP), any researchers affiliated with Korean institutes are eligible to apply for various observing modes in both hemispheres covered by Gemini North in Hawaii and by Gemini South in Chile. I am going to overview a overall capability of Gemini Observatory and to share a perspective on the Korean collaboration with Subaru/EAO community.
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Myungshin Im | Multi-Messenger Astronomy with Subaru |
In the past two years, we saw a significant progress in the way how we study the universe, with the simultaneous observations of the neutron star mergers in GW and EM, and the first identification of the cosmological neutrino source associated with a blazar. This multi-messenger astronomy (MMA) is now giving us a whole new view of the universe, through which we expect many interesting scientific discoveries to be made. The optical/NIR part of MMA efforts greatly benefit from observations from wide-field, large aperture telescopes, considering that the localization of the astrophysical sources is still poor for GW and neutrino observations and many such sources are likely to be fainter than R > 23 mag. We give a short overview of the MMA effort in Korea and the world, and suggest that a wide area survey of the northern sky can make be extremely helpful for the future MMA activities. The collaboration between EAO countries can possibly achieve such an ambitious goal.
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Akio Inoue | Hyper Suprime-Cam Narrowband Survey: CHORUS project |
We are conducting the CHORUS (Cosmic HydrOgen Reionization Unveiled with Subaru) project using multiple narrowband filters on Subaru/Hyper Suprime-Cam. I will present the current status of the project.
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Miho N. Ishigaki | Chemical abundance patterns in the Milky Way halo stars as constraints on the element production in the early Universe |
Thanks to recent large spectroscopic surveys of stars in the Milky Way, detailed elemental abundance measurements for an unprecedented number of nearby stars are now available. Furthermore, the Gaia satellite mission provides parallaxes and proper motions for the majority of these stars, which enables us to analyze six-dimensional phase-space information together with detailed chemical abundances among different stellar populations in the Milky Way. We study chemical abundance patterns in the Milky Way halo stars in terms of supernova nucleosynthesis yield models for metal-free and metal-poor stellar progenitors. I would like to present the results of our study and discuss their implications on nucleosynthesis sources and chemical evolution in the early Universe.
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Masateru Ishiguro | A Possible Collaboration in Solar System Research for EAO Subaru |
In this presentation, I will introduce the time domain science in the Solar System research field. Thanks to recent space explorations, as well as theoretical studies, we have a significant progress for understandings of the present states and evolution of the Solar System bodies, acquiring information from micrometer to celestial body’s scales, since >4 billion years ago until now. However, several new questions arise. Especially, sudden outbursts of comets and asteroids are still enigmatic and unsolved. Here I introduce observational evidences of these phenomena and suggest possible collaboration research under the framework of Subaru/EAO.
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James Jee | Subaru Weak Lensing Study of Merging Galaxy Clusters |
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Linhua Jiang | AGN/QSO |
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Takayuki Kotani | Exoplanet science and instrumentation with the Subaru telescope |
Subaru Telescope has a unique capability of studying exoplanets from the visible to the infrared wavelengths. I will talk about exoplanet science, ongoing and future instrumentation for exoplanet study. Especially recently commissioned attractive instruments, SCExAO, CHARIS, and Infrared Doppler (IRD) will allow us detailed studies of planet atmospheres, kinematics, planet formation mechanism, and to find a new habitable Earth-like planets.
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Minjin Kim | AGN science in conjunction with SPHEREx survey |
I will briefly overview SPHEREx space mission, which will provide unique spectroscopic imaging dataset. I will present AGN science cases that can be done with survey data from the SPHEREx mission. Lastly I will discuss potential Subaru-SPHEREx synergy for AGN studies.
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Yongjung Kim | Discoveries and Properties of IMS Quasars at z>5 |
High-redshift quasars are remarkable sample to understand the early universe. Based on the wide field surveys, hundreds of quasars have been discovered at high redshift (z > 5). But most of them are biased toward luminous ones, and it is only recently that faint quasars (M1450 > -24 mag) have been identified. Since faint quasars are thought to occupy a large portion of high-redshift quasars, research on them is required to see the nature of the whole population. In this talk, we will present our result from the Infrared Medium-deep Survey (IMS), the near-infrared imaging survey covering 120 square degrees are on the sky with the depths of J ~ 23 AB magnitudes. Combining the archive optical imaging data, we identified about 200 candidates for high-redshift quasar, and the number has been narrowed down to dozens of highly promising candidates with additional medium-band observations. Until now, about 10 faint quasars at z~5 and 6 have been spectroscopically identified with Gemini and Magellan telescopes. Our result so far suggests that the number of faint quasars may not be high enough to fully account for the cosmic reionization. Furthermore, we obtained a deep NIR spectrum of one of the faint quasars for the first time. This shows a very interesting result that IMS J2204+0112 contains a central black hole as massive as a billion solar mass, corresponding to the low Eddington ratio of 0.1. This low value is distinguishable from those of other luminous quasars at high redshift, implying two possible scenarios for the black hole growth in the early universe.Tadayuki Kodama |
Xu Kong | |
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Chien-Hsiu Lee | |
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Hyung Mok Lee | Multi-wavelength surveys of North Ecliptic Pole |
The spectral energy distribution (SED) is an important tool for the understanding the nature and evolutionary status of galaxies. However, it is not easy to derive full SEDs because we need redshift as well as photometric information over wide wavelength ranges. The North Ecliptic Pole (NEP) has been one of the favorite lines of sight for deep observations, especially for the space-based instruments on polar orbit. AKARI has carried out nearly continuous photometric surveys from 2 to 25 microns on NEP region. Subsequent observations at other wavelengths including the Subaru/HSC as well as spectroscopic surveys have bee carried out.The Subaru/HSC, together with the CFHT u-band data enable us to derive photometric redshifts for large fraction of AKARI sources at near- and mid-infrared mid-infrared bands. Recently, JCMT/SCUBA-2 survey at 850 micron, is under way as one of the Large Programs. Therefore additional synergy is expected when JCMT/SCUBA-2 survey is completed as the sub millimeter data will provide more accurate estimates of the total infrared luminosities for the star forming galaxies. In this talk, I will summarize the current status and research highlights of the multi-wavelength surveys toward the NEP region and future prospects.
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Myung Gyoon Lee | Deep and Wide Survey of Giant and Dwarf Galaxies |
What we learn from deep and wide surveys of giant and dwarf galaxies in the local universe will be reviewed.
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Young-Wook Lee | Is the evidence for dark energy secure from supernova cosmology? |
Type Ia supernova (SN Ia) cosmology provides the most direct evidence for the presence of dark energy. This result is based on the assumption that the lookback time evolution of SN Ia luminosity, after standardization, would be negligible. Recent studies show, however, that SN Ia luminosity is correlated with mass and morphology of host galaxies, implying possible dependence of SN Ia luminosity on host galaxy properties. In order to investigate this more directly, 7 years ago, we have initiated a spectroscopic survey for early-type host galaxies, for which population age and metallicity can be more reliably determined from absorption lines. We found a significant (3.9 sigma) correlation between host galaxy mass and population age among our sample, which implies that population age is mostly responsible for the well-established correlation between host mass and SN Ia luminosity. More interestingly, our results further show that there is a 2.1 sigma correlation between SN Ia luminosity (Hubble residual) and population age. We conclude that the luminosity evolution plays a major role in the systematic uncertainties of SN Ia cosmology.
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Matthew Lehner | Solar System Science with Subaru and HSC |
The Subaru Telescope and Hyper Suprime-Cam provide a unique platform for the exploration of the Solar System beyond Neptune. The combination of the large aperture and wide field provides the capability to perform a very deep and wide survey of the Trans-Neptunian region. In this talk I will summarize the science goals and technical plan of a large EAO Shared Time Proposal to search for Trans-Neptunian objects down to a limiting magnitude of r\'=26, which will cover around 150 square degrees. The survey will also discover and characterize a significant number of Jupiter trojans and asteroids.
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Haining Li | |
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Lihwai Lin | Galaxy Evolution |
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Fengshan Liu | Spatially Resolved View of Galaxy Assembly and Quenching over 0.5 |
Radial specific star formation rate (sSFR) gradients are crucial for determining how stellar mass is built up in galaxies as they evolve along the star formation main sequence (SFMS), and how and where the star formation shuts down as galaxies move off the SFMS to become fully quiescent. However, dust gradients have often been overlooked or treated to be subordinate when studying distant galaxies, which could be seriously distorting our view of the structure of distant galaxies without proper dust corrections. Although spectroscopic approaches perform better in disentangling the age(sSFR)-dust-metallicity degeneracy, they are largely limited by telescope time, spectrum quality and sample size, especially for distant galaxies. Now thank to the rich HST deep multi-band photometry data from HST/CANDELS, the age(sSFR)-dust-metallicity degeneracy can be partially broken up by fitting attenuated stellar population models to broad-band spectral energy distributions or by analyzing two-color (i.e., UVJ, UVI) diagrams of galaxies. In my talk, I will present a brief review of a series of works about the radial sSFR profiles of distant galaxies by our group, which are determined using the new multi-band multi-aperture photometry catalogs of the CANDELS. Our studies give a new and powerful insight into how distant galaxies assemble as they evolve along the SFMS, and how the star formation shuts down as they move off the SFMS. Finally, I will discuss the physical processes responsible for cessation of star formation in distant galaxies.
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Youjun Lu | TBD |
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Yoshiki Matsuoka | Quest for the most distant quasars with Subaru |
High-z quasars are an important probe of the distant Universe, for understanding the origin and progress of cosmic reionization, the early growth of supermassive black holes, and the evolution of the host galaxies. Subaru is making a significant contribution to this field in many aspects. We are carrying out a project in international collaboration to search for high-z quasars, by combining imaging data from Hyper Suprime-Cam and spectroscopic data from instruments on Subaru and other telescopes. I will review the project with a focus on some recent achievements, concluding with an outlook for the future.
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Norio Narita | Review of Recent Exoplanet Studies and Subaru\'s Capability |
As a keynote talk, I will review recent exoplanet studies in the world and Subaru\'s capability for future observations.
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Chow-Choong Ngeow | Classical Pulsating Stars in the Era of Modern Time-Domain Surveys: From ZTF to ULTIMATE-SUBARU |
Today there are a number of survey projects in time-domain astronomy aimed for detecting transients and microlensing events, such as ATLAS, ATLAS, CRTS, OGLE, PS2, PTF and others, that collected rich amount of imaging data. Besides searching of transients and microlensing events, light curves data from these surveys are also very valuable for the study of variable stars. In this presentation I will give such examples of using the light curves data in the investigation of classical pulsating stars: the use of ZTF (Zwicky Transients Facility) and OGLE (Optical Gravitational Lensing Experiment) data for the study of RR Lyrae and Mira variables, respectively. Connection of these work to a project proposed to ULTIMATE-SUBARU -- \"The Long Period Variables in Nearby Galaxies\", and its main science goal will and its main science goal will be discussed. A brief introduction to ZTF will also be included.
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Shogo Nishiyama | Subaru monitoring observations of an orbiting star around Galactic supermassive black hole |
During the closest approach of an orbiting star S0-2/S2 to the Galactic supermassive black hole (SMBH), the detection of the post-Newtonian effects has been expected. I will talk about our monitoring observations of S0-2 using Subaru/IRCS and their results during its closest approach in 2018. We have obtained high-resolution spectra of S0-2, and determined its radial velocities (RVs) using the Br-gamma absorption feature. Our RV curve during 2018 shows a clear discrepancy with that shown in GRAVITY Collaboration (2018) using VLT, but shows a good agreement with Keck/Gemini results. Our results show that the observed RV curve can be better explained by General Relativity, than Newtonian Gravity. This implies the detection of the General Relativistic effects from the supermassive black hole.
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Youichi Ohyama | Rapid Black Hole Growth at the Dawn of the Universe: A Super-Eddington Quasar at z=6.6 |
We present the analysis of a new NIR spectrum of a recently discovered z=6.621 quasar PSO J006+39 in an attempt to explore the early growth of supermassive black holes (SMBHs). This NIR (rest-frame UV) spectrum shows blue continuum slope and rich metal emission lines in addition to Ly-alpha line. The power-law slope index of the continuum emission is significantly bluer than the slope predicted from standard thin disc models. We fit the SED using an energetically self-consistent model based on the standard disk OPTXAGNF (Done et al. 2012). The result shows that the very blue slope is probably produced by a small radial (~230 gravitational radius) extent of the standard accretion disc. All plausible SED models require that the source is super-Eddington (Lbol/LEdd>=9), so the apparently small disc may simply be the inner funnel of a puffed up flow, and clearly the SMBH in this quasar is in a rapid growth phase.
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Teppei Okumura | TBD |
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Masato Onodera | Near-infrared spectroscopy of extreme emission line galaxies at z>3 |
We present the selection, spectroscopic identification, and physical properties of a population of extremely emission line galaxies (EELGs) at z>3. The selection is made based on the excess in observed K-band flux relative to stellar continuum models. Among 240 EELG candidates over the 2 sq. degree COSMOS field, 23 galaxies were observed using Subaru/MOIRCS and 19 of them are identified as EELGs at 3 |
Changbom Park | Workshop Summary |
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Juntai Shen | The Milky Way Structure in the Context of Local Group |
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Yong Shi | Star formation in nearby galaxies |
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Rhythm Shimakawa | Galaxy formation in protoclusters at the cosmic high noon |
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Hiro Takami | Exploration of Star and Planet Formation with Subaru: To date and in the future |
Subaru has been tremendously successful in revealing and understanding star and planet formation over the past 20 years. In this review talk I will highlight Subaru’s achievements to date, and discuss its science impact in the future, including synergies with other missions such as ALMA, TMT and SPICA.
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Naoyuki Tamura | The Subaru Prime Focus Spectrograph (PFS) Project |
PFS (Prime Focus Spectrograph), a next generation facility instruments on the Subaru Telescope, is a very wide-field, massively multiplexed, and optical \\& near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed in the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm at one exposure. The development of this instrument has been promoted by the international collaboration under the initiative of Kavli IPMU. Currently, the team are actively working on the integration and test of the subsystems and making substantial efforts for software development and related simulation efforts and, consequently, system integration at the observatory has successfully started in 2018. In parallel, the PFS science team has been actively developing the survey plan aiming to address key questions in three main fields: Cosmology, galaxy & AGN evolution, and Galactic archaeology, and from the joint implications, to understand the dark sector of the universe. The combination of the wide field, high multiplicity, and high number density of the fibers on the focal plane offers a unique opportunity of designing a unique survey on these three core science cases envisioned in the PFS SSP survey. This presentation will give an overview of the instrument, current project status and future future perspectives.
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Masaomi Tanaka | Multi-messenger Astronomy with Subaru |
Recent detection of gravitational waves from a neutron star merger opened the era of multi-messenger astronomy. Thanks to the wide field of view, Subaru Telescope plays important role to search an electromagnetic counterpart from a large localization area of gravitational wave events. Similar observing strategy can also be taken to identify the origins of high-energy neutrinos. I will review roles of Subaru telescope in the era of multi-messenger astronomy.
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Masayuki Tanaka | Nearby galaxies with HSC and PFS |
I will give a brief review of science cases on nearby galaxies with HSC and PFS.
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Jong-Hak Woo | AGN-driven gas outflows and feedback at low-z |
Galactic scale gas outflows are considered as a channel of AGN feedback to suppress or trigger star formation. To understand the role of mass-accreting supermassive black holes in galaxy evolution, it is of importance to investigate the effect of feedback on star formation. I will present the demography of AGN-driven ionized gas outflows at z < 0.3, focusing on the connection between outflows and star formation baed on a large statistical sample. Using a subsample of strong outflow AGNs, I will also discuss the spatially resolved outflows and star formation based on the integral field spectroscopy. Then, I will briefly discuss what we can study with the Subaru.
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Yujin Yang | Polarimetric Survey of Giant Lyman-Alpha Nebulae at High Redshift |
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Sukyoung Yi | Catching the first glimpse of disc galaxy formation from high resolution simulations |
We present a preliminary result from the New Horizon simulation. NewHorizon is a high resolution (maximum spatial resolution of 35pc) zoom-in simulation performed on a sphere with a 10Mpc radius extracted from the previous Horizon-AGN simulation. In this low density environment, we monitor the formation and evolution large galaxies down to z=0.7 and present how massive field galaxies shape up in the first half of the cosmic history. This can be compared with deep observations that are possible through large telescopes such as Subaru.
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Fumi Yoshida | Solar System Science with Subaru Telescope |
I will summarize the Solar System science, mainly on small bodies, with Subaru Telescope.
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Michitoshi Yoshida | Current Status of Subaru Telescope |
I present the current status of the Subaru Telescope operations. A large imaging survey with Hyper Suprime-Cam, HSC-SSP, for which 300 Subaru nights are allocated, is ongoing. About 75% of the survey has been completed and the second public data release from HSC-SSP will be made in 2019. A new instrument, InfraRed Doppler spectrograph (IRD), is now operational and a new large survey with IRD for detecting earth-like exoplanets around M dwarf stars, IRD-SSP, will be started from February 2019. The development of Prime Focus Spectrograph (PFS) is going well. The first spectrograph module of PFS will be delivered to Subaru around April 2019.
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Yongmin Yoon | Barred Galaxies Are More Abundant in Clusters That Are in Pairs Or with Substructures: Observational Evidence for Bar Formation via Cluster-Cluster Interactions |
Bars are an elongated structure that extends from a center of galaxies, and about one third of galaxies are known to possess bars. Two popular pictures for the bar formation are that bars form through a physical process inherent in galaxies, or through an external process such as galaxy-galaxy interaction. However, there are other plausible mechanisms to form bars that still need to be observationally tested. Here, we present the observational evidence that bars can form from another channel, namely a cluster-cluster interaction. We examined 105 galaxy clusters at 0.015 < z < 0.060 that are selected from the Sloan Digital Sky Survey data, and identified 16 interacting clusters. By examining the fraction of barred disk-dominated galaxies in these clusters, we find that the barred disk-dominated galaxy fraction is about 1.5 times higher in interacting clusters than in clusters with no clear signs of ongoing interaction (41% versus 27%). Our result indicates that bars can form due to a large scale violent phenomenon, and cluster-cluster interaction should be considered seriously as an important channel for bar formation.
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Ji-Lin Zhou | Recently works on exoplanets and Time Domain Observatory in Ali |
Here we present some of our recent work on exoplanet detection and statistics published in PANS, Nature Astronomy and ApJS. We also present our onging exoplanet Transit search in Dome A, Antarctic, and in Ali, Tibet, where we set an array of small telescopes (TIDO) for searching exoplanets and time-domain exvents. World-Wide Cooprations are welcome.
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