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The Hitachi and Takahagi 32 m radio telescopes: Upgrade of the antennas from satellite communication to radio astronomy

2016; Oxford University Press; Volume: 68; Issue: 5 Linguagem: Inglês

10.1093/pasj/psw045

2053-051X

Yoshinori Yonekura, Yu Saito, Koichiro Sugiyama, Kang Lou Soon, Munetake Momose, M. Yokosawa, Hideo Ogawa, Kimihiro Kimura, Yasuhiro Abe, Atsushi Nishimura, Yutaka Hasegawa, Kenta Fujisawa, Tomoaki Ohyama, Yusuke Kono, Yusuke Miyamoto, Satoko Sawada‐Satoh, Hideyuki Kobayashi, Noriyuki Kawaguchi, Mareki Honma, Katsunori M. Shibata, Katsuhisa Sato, Yuji Ueno, Takaaki Jike, Yoshiaki Tamura, Tomoya Hirota, Atsushi Miyazaki, Kotaro Niinuma, Kazuo Sorai, Hiroshi Takaba, Kazuya Hachisuka, Tetsuro Kondo, Mamoru Sekido, Yasuhiro Murata, Naomasa Nakai, Toshihiro Omodaka,

Gamma-ray bursts and supernovae

Abstract The Hitachi and Takahagi 32 m radio telescopes (former satellite communication antennas) were so upgraded as to work at 6, 8, and 22 GHz. We developed the receiver systems, IF systems, back-end systems (including samplers and recorders), and reference systems. We measured the performance of the antennas. The system temperature including the atmosphere toward the zenith, $T_{\rm sys}^{\ast }$, is measured to be ∼30–40 K for 6 GHz and ∼25–35 K for 8 GHz. $T_{\rm sys}^{\ast }$ for 22 GHz is measured to be ∼40–100 K in winter and ∼150–500 K in summer seasons, respectively. The aperture efficiency is 55%–75% for Hitachi at 6 GHz and 8 GHz, and 55%–65% for Takahagi at 8 GHz. The beam sizes at 6 GHz and 8 GHz are ∼4${^{\circ}_{.}}$6 and ∼3${^{\circ}_{.}}$8, respectively. The side-lobe level is less than 3%–4% at 6 and 8 GHz. Pointing accuracy was measured to be better than ∼0${^{\circ}_{.}}$3 for Hitachi and ∼0${^{\circ}_{.}}$6 for Takahagi. We succeeded in VLBI observations in 2010 August, indicating good performance of the antenna. We started single-dish monitoring observations of 6.7 GHz methanol maser sources in 2012 December, and found several new sources showing short-term periodic variation of the flux density.