| Autor: |
Honma, Mareki, Fujii, Takahiro, Hirota, Tomoya, Horiai, Koji, Iwadate, Kenzaburo, Jike, Takaaki, Kameya, Osamu, Kamohara, Ryuichi, Kan-ya, Yukitoshi, Kawaguchi, Noriyuki, Kobayashi, Hideyuki, Kuji, Seisuke, Kurayama, Tomoharu, Manabe, Seiji, Miyaji, Takeshi, Nakashima, Kouichirou, Omodaka, Toshihiro, Oyama, Tomoaki, Sakai, Satoshi, Sakakibara, Sei-ichiro, Sato, Katsuhisa, Sasao, Tetsuo, Shibata, Katsunori M., Shimizu, Rie, Suda, Hiroshi, Tamura, Yoshiaki, Ujihara, Hideki, Yoshimura, Akane |
| Zdroj: |
Publications of the Astronomical Society of Japan; August 2003, Vol. 55 Issue: 4 pL57-L60, 4p |
| Abstrakt: |
We present the results of the first dual-beam observations with VERA (VLBI Exploration of Radio Astrometry). The observations of a pair of $\mathrm{H}_2\mathrm{O}$maser sources, W 49N and OH 43.8$-$0.1, were carried out on 2002 May 29 and July 23, and fringes of the $\mathrm{H}_2\mathrm{O}$maser lines at 22 GHz were successfully detected. While the residual fringe phases of both sources showed rapid variations over $360^\circ$due to the atmospheric fluctuation, the differential phase between the two sources remained constant for 1 hour with an r.m.s. of $8^\circ$, demonstrating that the atmospheric phase fluctuation was effectively removed by dual-beam phase referencing. An analysis based on the Allan standard deviation reveals that the differential phase is mostly dominated by white phase noise, and the coherence function calculated from the differential phase shows that after phase referencing the fringe visibility can be integrated for an arbitrarily long time. These results demonstrate VERA’s high capability of phase referencing, indicating that it is a promising tool for phase-referencing VLBI astrometry at $10 \,\mu\mathrm{as}$-level accuracy. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
