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Flux monitoring observations of Sgr A* at 8 GHz and 2 GHz with the NICT Kashima–Koganei VLBI System

Published online by Cambridge University Press:  22 May 2014

S. Takekawa ,
T. Oka  and
M. Sekido
S. Takekawa
Affiliation:
Department of Physics, Faculty of Science and Technology, Keio University 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, Japan email: [email protected]
T. Oka
Affiliation:
Department of Physics, Faculty of Science and Technology, Keio University 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, Japan email: [email protected]
M. Sekido
Affiliation:
Space-Time Standards Laboratory, Kashima Space Technology Center, National Insitute of Information and Communications Technology 893-1 Hirai, Kashima, Ibaraki, Japan
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Abstract

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We have been conducting flux monitoring observations of Sgr A* at 8 GHz and 2 GHz using the NICT Kashima-Koganei VLBI system (109 km baseline) since mid-February 2013. The primary objective of the monitoring is a search for flux variation which is expected to be caused by the interaction between the G2 cloud and the accretion disk. Until 2013 September 22, we observed Sgr A* for 39 days, five hours on each day. Four quasars (NRAO 530, PKS 1622–253, PKS 1622–297, PKS 1921–293) were also observed as flux calibrators every 6 minutes. No significant change nor variation has been detected in the 8 GHz flux density of Sgr A*. The 8 GHz flux density was 0.81 ± 0.07 Jy (preliminary), while no significant 2 GHz emission was detected by our system. We will continue monitoring as often as possible until at least 2014 May.

Keywords

Galaxy: center — Galaxy: nucleus — radio continuum: galaxies
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 9 , Symposium S303: The Galactic Center: Feeding and Feedback in a Normal Galactic Nucleus , October 2013 , pp. 330 - 332
Copyright
Copyright © International Astronomical Union 2014 

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