National Astronomical Observatory Of Japan Research Articles

Evaluation of kinetic-inductance nonlinearity in a single-crystal NbTiN-based coplanar waveguide

Masanori Takeda*, Takafumi Kojima, Atsushi Saito, Kazumasa Makise, and Hisashi Shimakage 1Graduate School of Integrated Science and Technology, Shizuoka University, Hamamatsu, Shizuoka 432-8011, Japan 2Advanced Technology Center, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan 3Graduate School of Science and Engineering, Yamagata University, Yonezawa, Yamagata 992-8510, Japan 4Advanced ICT Research Center, NICT, Kobe, Hyogo 651-2492, Japan 5College of Engineering, Ibaraki University, Hitachi, Ibaraki 316-8511, Japan

Thirty Meter Telescope Detailed Science Case: 2015**Cover image: artist's rendition of the TMT International Observatory on Mauna Kea opening in the late evening before beginning operations.

The TMT Detailed Science Case describes the transformational science that the Thirty Meter Telescope will enable. Planned to begin science operations in 2024, TMT will open up opportunities for revolutionary discoveries in essentially every field of astronomy, astrophysics and cosmology, seeing much fainter objects much more clearly than existing telescopes. Per this capability, TMT's science agenda fills all of space and time, from nearby comets and asteroids, to exoplanets, to the most distant galaxies, and all the way back to the very first sources of light in the universe. More than 150 astronomers from within the TMT partnership and beyond offered input in compiling the new 2015 Detailed Science Case. The contributing astronomers represent the entire TMT partnership, including the California Institute of Technology (Caltech), the Indian Institute of Astrophysics (IIA), the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC), the National Astronomical Observatory of Japan (NAOJ), the University of California, the Association of Canadian Universities for Research in Astronomy (ACURA) and US associate partner, the Association of Universities for Research in Astronomy (AURA).

LARGE INTERNATIONAL PROJECTS AT THE NATIONAL ASTRONOMICAL OBSERVATORY OF JAPAN

This paper presents an overview of the large international projects in which the National Astronomical Observatory of Japan is involved, namely, the Subaru Telescope, Atacama Large Millimeter/submillimeter Array, and the Thirty Meter Telescope. The last section provides a brief historical view of the international collaboration in East Asia regions over the last 20 years.

A NEW HARDWARE CORRELATOR IN KOREA: PERFORMANCE EVALUATION USING KVN OBSERVATIONS

We report results of the performance evaluation of a new hardware correlator in Korea, the Daejeon correlator, developed by the Korea Astronomy and Space Science Institute (KASI) and the National Astronomical Observatory of Japan (NAOJ). We conduct Very Long Baseline Interferometry (VLBI) observations at 22 GHz with the Korean VLBI Network (KVN) in Korea and the VLBI Exploration of Radio Astrometry (VERA) in Japan, and correlated the aquired data with the Daejeon correlator. For evaluating the performance of the new hardware correlator, we compare the correlation outputs from the Daejeon correlator for KVN observations with those from a software correlator, the Distributed FX (DiFX). We investigate the correlated flux densities and brightness distributions of extragalactic compact radio sources. The comparison of the two correlator outputs shows that they are consistent with each other within < 8%, which is comparable with the amplitude calibration uncertainties of KVN observations at 22 GHz. We also find that the 8% difference in flux density is caused mainly by (a) the difference in the way of fringe phase tracking between the DiFX software correlator and the Daejeon hardware correlator, and (b) an unusual pattern (a double-layer pattern) of the amplitude correlation output from the Daejeon correlator. The visibility amplitude loss by the double-layer pattern is as small as 3%. We conclude that the new hardware correlator produces reasonable correlation outputs for continuum observations, which are consistent with the outputs from the DiFX software correlator.

Homologous Helical Jets: Observations By IRIS, SDO, and Hinode and Magnetic Modeling With Data‐Driven

Data are courtesy of the science teams of IRIS, SDO, and Hinode. IRIS is a NASA small explorer mission developed and operated by LMSAL with mission operations executed at NASA Ames Research center and major contributions to downlink communications funded by the Norwegian Space Center (NSC, Norway) through an ESA PRODEX contract. This work is supported by NASA under contract NNG09FA40C (IRIS), the European Research Council grant agreement No. 291058, and contract 8100002705 from LMSAL to SAO. Additionally, M.C.M.C. acknowledges support from NASA’s SDO/AIA (NNG04EA00C) and Hinode/SOT (NNM07AA01C) contracts and grants (NNX14AI14G and NNX13AJ96G) to LMSAL. AIA is an instrument on board the Solar Dynamics Observatory, a mission for NASA’s Living With a Star program. Hinode is a Japanese mission developed and launched by ISAS/JAXA, collaborating with NAOJ as domestic partner, and NASA and STFC (UK) as international partners. Science operation of Hinode is conducted by the Hinode science team organized at ISAS/JAXA. Postlaunch operation support is provided by JAXA and NAOJ (Japan), STFC (UK), NASA, ESA, and NSC (Norway). The numerical modeling work is made possible by NASA’s High-End Computing Program. The simulations presented in this paper were carried out on the Pleiades cluster at the Ames Research Center.

Development of Microwave Kinetic Inductance Detector for Cosmological Observations

A precise measurement of Cosmic Microwave Background (CMB) provides us rich information about the universe. In particular, its asymmetric polarization patterns, B-modes, are smoking gun signature of inflationary universe. Magnitude of the B-modes is order of 10 nK. Its measurement requires a high sensitive millimeter-wave telescope with a large number of superconducting detectors on its focal plane. Microwave Kinetic Inductance Detector (MKID) is appropriate detector for this purpose. MKID camera has been developed in cooperation of National Astronomical Observatory of Japan (NAOJ), Institute of Physical and Chemical Research (RIKEN), High Energy Accelerator Research Organization (KEK), and Okayama University. Our developments of MKID include: fabrication of high-quality superconducting film; optical components for a camera use; and readout electronics. For performance evaluation of total integrated system of our MKID camera, a calibration system was also developed. The system was incorporated in a 0.1 K dilution refrigerator with modulated polarization source. These developed technologies are applicable to other types of detectors.

S1360102 板ばねを利用した研磨による月面反射鏡の平滑加工技術の開発

A high precision measurement system of the distance between the moon and earth is under development by the National astronomical observatory of Japan, in which the round-trip time of laser from the earth to the moon is measured to calculate the distance. In the system, a new lunar laser reflector (LLR) placed on the moon is necessary to measure the round-trip time, but has not yet been realized. In this study, we proposed a new polishing method using a plate spring suitable for polishing the LLR to realize it. To evaluate our proposed method, we polished single crystal Si wafers as workpieces, and examined surface roughness and machined shapes of the polished areas. As a result, surface roughness after the polishing was better than that before polishing. This proves that our proposed method using the plate spring enables the smoothing of surfaces. However, the machined areas were not shaped to flat, but to be curved. The reason for this is possibly due to the non-uniformity of the polishing load. Thus, the flatness of the machined areas should be improved in future study.

Solar Full-Disk Polarization Measurement with the Fe I 15648 Å Line

AbstractThe near-infrared absorption line Fe I 15648 Å, which has a Landég-factor of 3, shows a particularly large Zeeman splitting. We regularly take full-disk polarization maps of the Sun in the Fe I 15648 Å line (as well as the He I 10830 Å line) with an infrared spectropolarimeter installed at the Solar Flare Telescope of the National Astronomical Observatory of Japan (NAOJ). It is known that weak, mostly horizontal magnetic fields are ubiquitously distributed in the quiet regions of the Sun, while the strong magnetic fields are concentrated in active regions and network boundaries. The weak horizontal field has not been sufficiently investigated due to the difficulty of such observations. The polarization maps in Fe I 15648 Å show the magnetic field strength at each pixel, regardless of the filling factor, so we can easily isolate the weak horizontal field signals from strong magnetic field ones using the StokesVprofiles of the Fe I 15648 Å line. Here we present instrumental aspects and observational results of solar near-infrared full-disk polarimetry. We highlight the weak horizontal field inferred from Fe I 15648 Å.

Measurement of MKID Performance with High-Speed and Wide-Band Readout System

Microwave kinetic inductance detectors (MKIDs) are being developed at the National Astronomical Observatory of Japan to enable precise measurements of the cosmic microwave background. One of the features of MKIDs is scalability using a frequency-division multiplexing (FDMUX) readout scheme. A digital fast fourier transform spectrometer (FFTS) is a good way to read out a number of resonance frequencies simultaneously and fully utilize the advantage of FDMUX of MKIDs. We have developed FFTS readout electronics using an ADC/DAC with 1 Gsps (sample per second) sampling rate and 270 MHz bandwidth. We measured the noise characteristics of a single MKID in the frequency range of 60 Hz–30 kHz with this readout system, and found the noise was almost equivalent to the noise measured by ordinary analog IQ down-converter readout. This indicates our FFTS electronics do not add any additional noise to the MKID readout system over the frequency range.

Cover

The background image for the meeting's logo is “The great comet of 1882”—an image from the archives of the National Astronomical Observatory of Japan.

Long-term synoptic observations of the Sun at the National Astronomical Observatory of Japan

The National Astronomical Observatory of Japan started regular synoptic solar observations about 100 years ago. At the beginning, Ca K spectroheliograms and white-light photographs were taken, and various other types of observations have been added. These historical data have been digitized and are now open at our web site (http://solarwww.mtk.nao.ac.jp/en/solarobs.html). Currently we are operating high-resolution imaging observations in the Hα line, the green continuum, and the G-band. Besides various kinds of imaging observations, magnetic field measurements have been carried out for about 30 years. We recently started to conduct full-Sun spectropolarimetry observations in the lines of He 10830 Å/Si 10827 Å and Fe 15648 Å. These near infrared observations show the magnetic field evolutions in both the photosphere and the chromosphere. In this paper, we present our data, which are expected to contribute to studying the long-term change of the solar activity.

The scientific goal of the Japanese small astrometric satellite, Small-JASMINE

AbstractSmall-JASMINE is a small Japanese astrometric satellite, developed mainly at the National Astronomical Observatory of Japan. The target launch date of Small-JASMINE is around 2017. The satellite will be equipped with a telescope with an aperture size of 30 cm and a focal length of approximately 3.9 m. The operational wavelength will be centered on the infrared Hw band, between 1.1 and 1.7 μm, using a HgCdTe detector with 4k × 4k pixels. This will enable us to observe the central regions of our Galaxy and clarify the dynamical structure of the bulge region. A restricted region of the Galactic bulge will be observed using a frame-linking method, which is different from the approach taken by both Hipparcos and Gaia, both developed at ESA. The target accuracy of the annual parallax and proper motion is approximately 10 μas and 10 μas yr−1, respectively, in the central region of the survey area of 0.3 × 0.3 deg2. The target accuracy of the annual parallax, ~ 50 μas, and that of the proper motion, ~ 50 μas yr−1, will be obtained within a region of 2 × 2 deg2. The observing region covers a field of approximately 3 × 3 deg2. The mission is required to continue for around three years to obtain reliable measurements. In the winter season, the angular distance between the Sun and the Galactic bulge region is small. Accordingly, we may have the chance to observe different regions which contain scientifically interesting targets, such as Cygnus X-1. If we are successful in observing the object over the course of a few weeks, the orbital elements of the star accompanying Cygnus X-1 can be resolved by Small-JASMINE.

Magnetic Helicity of Solar Active Regions as Revealed by Vector Magnetograms and Coronal X-Ray Images

Abstract We have used photospheric vector magnetograms of 15 different solar active regions to calculate the current helicity parameter, $ \alpha _{\rm av}$ , and the linear force-free field (LFFF) parameter, $ \alpha _{\rm best}$ , that fits best the observed transverse field. The data were obtained with the Solar Magnetic Field Telescope at the Huairou Solar Observing Station, the National Astronomical Observatories of China, the Solar Flare Telescope of the National Astronomical Observatory of Japan, and the Haleakala Stokes Polarimeter at the Mees Solar Observatory, University of Hawaii, from 1997 to 2000. The agreement in sign of $ \alpha _{\rm av}$ between three vector magnetographs is better than 90%. For $ \alpha _{\rm best}$ , the agreement is 80%–90%. The line-of-sight magnetograms observed with the Michelson–Doppler Imager (MDI) on SOHO and coronal X-ray images observed with the Soft X-ray Telescope (SXT) on Yohkoh have been used to determine the constant $ \alpha _{\rm c}$ of the LFFF in the corona. The value of $ \alpha _{\rm c}$ corresponds to the extrapolated coronal field whose field lines best match, by visual inspection, the structure of coronal loops in X-ray images. It is found that the sign agreement between photospheric $ \alpha _{\rm av}$ or $ \alpha _{\rm best}$ and coronal $ \alpha _{\rm c}$ is lower (60%–85%). We consider the differences in measurements, observing conditions, data reduction methods, and limitation in LFFF extrapolation, and discuss their contributions to the dispersions in the hemispheric sign rule of helicity.

S192024 低軌道衛星追尾のためのアンテナ指向に関する研究

The purpose of the research is to establish a calibration method for antenna pointing, which has difficulty in observing stars except the sun because of its low cost but noisy receiver, nor has its own calibration system. Two approaches are suggested in this paper. First method is the estimation of the target direction using the received signal. This is real time estimation, using Unscented Kalman Filter based on Cross-Scan method. Second is off-line estimation, which calculates coordinate of antenna using the result of the real time estimation. The first method was tested by simulation and the experiment tracking the sun. It was found that antenna will be able to track the sun for more than 4 hours autonomously. In the experiment, Φ3m parabola for Nano-JASMINE, nano-satellite for astrometry being developed by National Astronomical Observatory of Japan, the University of Tokyo, was used. The second method was tested by simulation and it was indicated that the pointing error would be less than 0.3degree.

Fragmentation of the HAYABUSA Spacecraft on Re-Entry

We succeeded in monitoring fragmentation of the main body of the HAYABUSA spacecraft upon its re-entry as a part of an expedition by the National Astronomical Observatory of Japan. The time variation of the number of fragments and their size distribution were derived by analyzing obtained images. The fragmentation started at 13$^{\rm h}$52$^{\rm m}$5$.\!\!\!^{\rm s}$2 UT at 83–84 km above sea level, and the number of fragments increased with time. The maximum number was more than a few hundred at around 13$^{\rm h}$52$^{\rm m}$20$^{\rm s}$, and the fragments dispersed over an area of more than 14 km in length, and 1 km in width along the re-entry trajectory. Fragments decreased in number after the maximum, and almost disappeared at 13$^{\rm h}$52$^{\rm m}$31$.\!\!\!^{\rm s}$3 at around a height of 45 km. Under some assumptions, we managed to derive the size distribution of the fragments, which showed a small power-law index within a range of $-$0.8 to $-$1.0. These values are lower than those of fragmentations of comets, or other examples in our solar system. The obtained flat size distribution is discussed based on a comparison of the intrinsic size distribution of the assembled parts of the HAYABUSA spacecraft.

A solar station in Ica - Mutsumi Ishitsuka: a research center to improve education at the university and schools

AbstractThe San Luis Gonzaga National University of Ica has built a solar station, in collaboration with the Geophysical Institute of Peru, the National Astronomical Observatory of Japan and the Hida Observatory. The Solar Station has the following equipment: a digital Spectrograph Solar Refractor Telescope Takahashi 15 cm aperture, 60 cm reflector telescope aperture, a magnetometer-MAGDAS/CPNM and a Burst Monitor Telescope Solar-FMT (Project CHAIN). These teams support the development of astronomical science and Ica in Peru, likewise contributing to science worldwide. The development of basic science will be guaranteed when university students, professors and researchers work together. The Solar Station will be useful for studying the different levels of university education and also for the general public. The Solar Station will be a good way to spread science in the region through public disclosure.

The Relative Phase Asynchronization between Sunspot Numbers and Polar Faculae

The monthly sunspot numbers compiled by Temmer et al. and the monthly polar faculae from observations of the National Astronomical Observatory of Japan, for the interval of March 1954 to March 1996, are used to investigate the phase relationship between polar faculae and sunspot activity for total solar disk and for both hemispheres in solar cycles 19, 20, 21 and 22. We found that (1) the polar faculae begin earlier than sunspot activity, and the phase difference exhibits a consistent behaviour for different hemispheres in each of the solar cycles, implying that this phenomenon should not be regarded as a stochastic fluctuation; (2) the inverse correlation between polar faculae and sunspot numbers is not only a long-term behaviour, but also exists in short time range; (3) the polar faculae show leads of about 50-71 months relative to sunspot numbers, and the phase difference between them varies with solar cycle; (4) the phase difference value in the northern hemisphere differs from that in the southern hemisphere in a solar cycle, which means that phase difference also existed between the two hemispheres. Moreover, the phase difference between the two hemispheres exhibits a periodical behaviour. Our results seem to support the finding of Hiremath (2010).

Satellite Design Methodology To Suppress Time-varying Residual Magnet Effects on Attitude For Nano-Satellites

AbstractAn astrometry satellite for Infrared Exploration “Nano-JASMINE” is being developed by intelligent Space System Laboratory (ISSL) University of Tokyo in cooperation with National Astronomical Observatory of Japan (NAOJ). The main objective of this mission is to measure 3-D positions of stars in our galaxy. In order to get the astrometry data accurately, the attitude should be stabilized to less than 740mas/8.8s (4×10−7 rad/s) during observations. In nano-satellites, magnetic disturbances are dominant attitude disturbances unlike large satellites. Magnetic disturbances are caused by the interaction between the Residual Magnetic Moment (RMM) of the satellite and the geo-magnetic field. To decrease magnetic disturbances accurately, we must cope with not only constant components of the RMM but also time-varying components of the RMM, and this problem is not needed to consider in large-satellites. Therefore, there are few established design methods, evaluating methods and measuring techniques about magnetism. In this paper, we introduce the new approach to the magnetic management for nano-satellites which require high-accuracy attitude stability.

Astronomical Virtual Observatories Through International Collaboration

Astronomical Virtual Observatories (VOs) are emerging research environment for astronomy, and 16 countries and a region have funded to develop their VOs based on international standard protocols for interoperability. The 16 funded VO projects have established the International Virtual Observatory Alliance (http://www.ivoa.net/) to develop the standard interoperable interfaces such as registry (meta data), data access, query languages, output format (VOTable), data model, application interface, and so on. The IVOA members have constructed each VO environment through the IVOA interfaces. National Astronomical Observatory of Japan (NAOJ) started its VO project (Japanese Virtual Observatory - JVO) in 2002, and developed its VO system. We have succeeded to interoperate the latest JVO system with other VOs in the USA and Europe since December 2004. Observed data by the Subaru telescope, satellite data taken by the JAXA/ISAS, etc. are connected to the JVO system. Successful interoperation of the JVO system with other VOs means that astronomers in the world will be able to utilize top-level data obtained by these telescopes from anywhere in the world at anytime. System design of the JVO system, experiences during our development including problems of current standard protocols defined in the IVOA, and proposals to resolve these problems in the near future are described.

About Nano-JASMINE Satellite System and Project Status

Intelligent Space Systems Laboratory, The University of Tokyo (ISSL) and National Astronomical Observatory of Japan (NAO) have been developing a small infrared astrometry satellite named “Nano-JASMINE”. The satellite size is about 50cm cubic and 20kg, which plays a pre-cursor role of JASMINE Project which is programmed by NAO and JAXA. In addition, since there has been only one astrometry satellite HIPPARCOS by ESA in the past, Nano-JASMINE is also expected to achieve certain scientific results in the field of astrometry. In this project, ISSL aims to develop new advanced small satellite bus system whose performance is comparable to that of 100-500kg sized satellites, including attitude stability of 1 arc-second and thermal stability of the mission subsystem of 1 mK. This paper overviews the Nano-JASMINE bus system with emphasis on attitude and thermal control systems.