Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-29T06:12:45.972Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

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 

References

Ryu, S. G., et al. 2012, AIPC 1427, 284Google Scholar
Gillessen, S.et al. 2012, Nature 481, 51Google Scholar
Gillessen, S.et al. 2013, ApJ 774, 44CrossRefGoogle Scholar
Phifer, K.et al. 2013, ApJ 773, 13Google Scholar
Narayan, R.et al. 2012, ApJL 757, L20Google Scholar
Crumley, P. and Kumar, P. 2013, arXiv: 1309.1762Google Scholar
Healey, S. E.et al. 2007, ApJS 171, 61Google Scholar