Journal ArticleDOI
Gigabit Digital Filter Bank: Digital Backend Subsystem in the VERA Data-Acquisition System
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TLDR
The Gigabit Digital Filter Bank (GDFB) as discussed by the authors was developed for the VERA project, which is a project to construct a new Japanese VLBI array dedicated to make a 3D map of our Milky Way Galaxy in terms of high precision astrometry.Abstract:
The VERA terminal is a new data-acquisition system developed for the VERA project, which is a project to construct a new Japanese VLBI array dedicated to make a 3-D map of our Milky Way Galaxy in terms of highprecision astrometry. New technology, a gigabit digital filter, was introduced in the development. The importance and advantages of a digital filter for radio astronomy have been studied as follows: (1) the digital filter can realize a variety of observation modes and maintain compatibility with different data-acquisition systems (Kiuchi et al. 1997 and Iguchi et al. 2000a), (2) the folding noise occurring in the sampling process can be reduced by combination with a higher-order sampling technique (Iguchi, Kawaguchi 2002), (3) and an ideal sharp cut-off bandedge and a flat amplitude/phase responses are approached by using a large number of taps available to use LSI of a large number of logic cells (Iguchi et al. 2000a). We developed the custom Finite Impulse Response filter chips and manufactured the Gigabit Digital Filter Banks (GDFBs) as a digital backend subsystem in the VERA terminal. In this paper, the design and development of the GDFB are presented in detail, and the performances and demonstrations of the developed GDFB are shown.read more
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Journal ArticleDOI
THE KCAL VERA 22 GHz CALIBRATOR SURVEY
TL;DR: In this paper, a sample of 1536 sources with correlated flux densities brighter than 200 mJy at 8 GHz with the very long baseline interferometry (VLBI) array VLBI Exploration of Radio Astrometry at 22 GHz was observed.
Journal ArticleDOI
Multi-Epoch VERA Observations of Sagittarius A*. I. Images and Structural Variability
TL;DR: In this article, the authors reported the results of multi-epoch observations of Sgr A* with VLBI Exploration of Radio Astrometry (VERA) at 43 GHz, carried out from 2004 to 2008.
Journal ArticleDOI
VLBI Observations of H2O Maser Annual Parallax and Proper Motion in IRAS 20143+3634: Reflection on the Galactic Constants
Ross A. Burns,Yoshiyuki Yamaguchi,Toshihiro Handa,Toshihiro Omodaka,Takumi Nagayama,Akiharu Nakagawa,Masahiko Hayashi,Tatsuya Kamezaki,James O. Chibueze,Makoto Shizugami,Makoto Nakano +10 more
TL;DR: In this article, the authors reported the results of VLBI observations of H2O masers in the IRAS 20143+3634 star forming region using VERA (VLBI Exploration of Radio Astronomy).
Journal ArticleDOI
Variable Asymmetry of the Circumstellar Envelope in IK Tauri Traced by SiO Maser Emission
Naoko Matsumoto,Naoko Matsumoto,Toshihiro Omodaka,Hiroshi Imai,Rie Shimizu,Takeshi Bushimata,Yoon Kyung Choi,Tomoya Hirota,Mareki Honma,Noritomo Inomata,Kenzaburo Iwadate,Takaaki Jike,Seiji Kameno,Osamu Kameya,Ryuichi Kamohara,Yukitoshi Kan-ya,Noriyuki Kawaguchi,Hideyuki Kobayashi,Seisuke Kuji,Tomoharu Kurayama,Toshihisa Maeda,Seiji Manabe,Takeshi Miyaji,Akiharu Nakagawa,Takumi Nagayama,Koichiro Nakashima,Chung Sik Oh,Tomoaki Oyama,Satoshi Sakai,Sei-ichiro Sakakibara,Tetsuo Sasao,Tetsuo Sasao,Katsuhisa Sato,Katsunori M. Shibata,Motonobu Shintani,Yoshiaki Sofue,Kasumi Sora,Hiroshi Suda,Yoshiaki Tamura,Miyuki Tsushima,Kazuyoshi Yamashita +40 more
TL;DR: In this paper, the authors observed the SiO (v = 1 and v = 2, J = 1-0) maser emissions toward the Mira variable IK Tauri (IK Tau, NML Tau, IRC +10050) over nine epochs from 2003 November to 2005 April using the VLBI Exploration of Radio Astrometry (VERA) telescope array.
Journal ArticleDOI
Trigonometric distance and proper motion of iras 20056+3350: a massive star-forming region on the solar circle
Ross A. Burns,Takumi Nagayama,Toshihiro Handa,Toshihiro Omodaka,Akiharu Nakagawa,Hiroyuki Nakanishi,Masahiko Hayashi,Makoto Shizugami +7 more
TL;DR: In this paper, the authors measured the trigonometric distance and proper motion of IRAS 20056+3350, obtained from the annual parallax of H{sub 2}O masers, and used their results to estimate the angular velocity of Galactic rotation at the Galactocentric distance of the Sun, Ω{sub 0} = 29.29 km s{sup −1} kpc{sup 1}
References
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Interferometry and Synthesis in Radio Astronomy
TL;DR: In this paper, a theory of interferometry and synthesis imaging analysis of the Interferometer Response Geometric Relationships and Polarimetry Antennas and Arrays Response of the receiving system Design of the Analog Receiving System Digital Signal Processing Very-Long-Baseline Interferometry Calibration and Fourier Transformation of Visibility Data Deconvolution, Adaptive Calibrration, and Applications Interferometers Techniques for Astrometry and Geodesy Propagation Effects Van Cittert-Zernike Theorem, Spatial Coherence, and
Journal ArticleDOI
Orbital motion in the radio galaxy 3C 66B: evidence for a supermassive black hole binary.
TL;DR: Using the very-long-baseline interferometer, it is found that the unresolved radio core of 3C 66B shows well-defined elliptical motions with a period of 1.05 ± 0.03 years, which provides a direct detection of a supermassive black hole binary.
Proceedings ArticleDOI
Digital Spectrometers for the Nobeyama 45-m Telescope
Kazuo Sorai,Kazuyoshi Sunada,Sachiko K. Okumura,Iwasa Tetsuro,Atsushi Tanaka,Kazuhito Natori,Hirofumi Onuki +6 more
TL;DR: In this paper, a commercial digital oscilloscope is used as a digitizer for the 25-BEam Array Receiver System (BEARS) of the Nobeyama 45m telescope.
Proceedings ArticleDOI
BEARS. SIS 25-BEam Array Receiver System for the NRO 45-m Telescope.
Kazuyoshi Sunada,Chieko Yamaguchi,Naomasa Nakai,Kazuo Sorai,Sachiko K. Okumura,Nobuharu Ukita +5 more
TL;DR: In this article, the SIS 25-BEam Array Receiver System (BEARS) is described, which is a large focal plane array receiver system for the NRO 45 m telescope.
Journal ArticleDOI
First Fringe Detection with VERA's Dual-Beam System and Its Phase-Referencing Capability
Mareki Honma,T. Fujii,Tomoya Hirota,K. Horiai,Kenzaburo Iwadate,Takaaki Jike,Osamu Kameya,Ryuichi Kamohara,Yukitoshi Kan-ya,Noriyuki Kawaguchi,Hideyuki Kobayashi,Seisuke Kuji,Tomoharu Kurayama,Seiji Manabe,Takeshi Miyaji,Kouichirou Nakashima,Toshihiro Omodaka,Tomoaki Oyama,Satoshi Sakai,Sei-ichiro Sakakibara,Katsuhisa Sato,Tetsuo Sasao,Katsunori M. Shibata,Rie Shimizu,Hiroshi Suda,Yoshiaki Tamura,Hideki Ujihara,Akane Yoshimura +27 more
TL;DR: In this paper, the results of the first dual-beam observations with VERA (VLBI Exploration of Radio Astrometry) were presented, and the results demonstrate the high capability of phase referencing, indicating that it is a promising tool for phase-referencing VLBI astrometry at 10 µas-level accuracy.
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