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
Annual Parallax Measurements of an Infrared Dark Cloud MSXDC G034.43+00.24 with VERA
Tomoharu Kurayama,Akiharu Nakagawa,Satoko Sawada-Satoh,Katsuhisa Sato,Mareki Honma,Kazuyoshi Sunada,Tomoya Hirota,Hiroshi Imai +7 more
TL;DR: In this paper, the authors measured the annual parallax of the H2O maser source associated with an infrared dark cloud MSXDC G034.43+00.24 from the observations with VERA (VLBI Exploration of Radio Astrometry).
Journal ArticleDOI
VERA 22 GHz Fringe Search Survey
Leonid Petrov,Tomoya Hirota,Mareki Honma,Katsunori M. Shibata,Takaaki Jike,Hideyuki Kobayashi +5 more
TL;DR: In this article, the authors presented results of a survey search for bright compact radio sources at 22 GHz with the VERA radio interferometer, where each source from a list of 2494 objects was observed in one scan for 2 minutes.
Journal ArticleDOI
A 'water spout' maser jet in S235AB-MIR
Ross A. Burns,Hiroshi Imai,Toshihiro Handa,Toshihiro Omodaka,Akiharu Nakagawa,Takumi Nagayama,Yuji Ueno +6 more
TL;DR: In this article, the authors report on annual parallax and proper motion observations of H2O masers in S235ABMIR, which is a massive young stellar object in the Perseus Arm.
Journal ArticleDOI
Astrometry of Galactic Star-Forming Region Onsala 1 with VERA: Estimation of Angular Velocity of Galactic Rotation at Sun
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TL;DR: In this article, the authors measured a trigonometric parallax of 0.404+/-0.017 mas, corresponding to a distance of 2.47+/- 0.11 kpc, which is larger than the IAU recommended value of 25.9 km/s/kpc.
Journal ArticleDOI
Astrometry of H2O Masers in the Massive Star-Forming Region IRAS 06061+2151 with VERA
Kotaro Niinuma,Takumi Nagayama,Tomoya Hirota,Mareki Honma,Kazuhito Motogi,Akiharu Nakagawa,Tomoharu Kurayama,Yukitoshi Kan-ya,Noriyuki Kawaguchi,Hideyuki Kobayashi,Yuji Ueno +10 more
TL;DR: In this article, the authors measured the trigonometric annual parallax of an H2O maser source associated with the massive starforming region IRAS 06061+2151 with VERA.
References
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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
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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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