Proper Motion of the Compact, Nonthermal Radio Source in the Galactic Center, Sagittarius A*

We review the current observational status of Sgr A∗, the compact nonthermal radio source at the galactic center. Sgr A∗ is a unique radio source at a unique location of the Galaxy. It is unlike any compact radio source associated with known stellar objects, but it is similar to extragalactic nuclear compact radio sources. The positional offset between Sgr A∗ and IRS16 places little constraint on the nature of the underlying energy source, since IRS16 need not be the core of the central star cluster. Sgr A∗ is still the best candidate for marking the location of a massive collapsed object.

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The galactic center compact nonthermal radio source

10.1063/1.36435 ◽

1987 ◽

Cited By ~ 4

Author(s):

K. Y. Lo

Keyword(s):

Radio Source ◽

Galactic Center ◽

Nonthermal Radio

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The 3-mm flux density monitoring of Sagittarius A* with the ATCA

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308019078 ◽

2007 ◽

Vol 3 (S248) ◽

pp. 204-205

Author(s):

J. Li ◽

Z. Q. Shen ◽

A. Miyazaki ◽

M. Miyoshi ◽

T. Tsutsumi ◽

...

Keyword(s):

Radio Source ◽

Flux Density ◽

Galactic Center ◽

Sagittarius A ◽

Compact Radio Source ◽

Sgr A

AbstractWe have performed monitoring observations of the 3-mm flux density toward the Galactic center compact radio source Sgr A* with the ATCA since 2005 October. It has been found that during several observing epochs Sgr A* was quite active, showing significant intraday variation. Here we report the detection of an IDV in Sgr A* on 2006 August 13, which exhibits a 27% fractional variation in about 2 hrs.

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The Galactic Center

Symposium - International Astronomical Union ◽

10.1017/s0074180900078232 ◽

1984 ◽

Vol 110 ◽

pp. 265-273

Author(s):

K. Y. Lo

Keyword(s):

High Resolution ◽

Radio Source ◽

Galactic Center ◽

Minor Axis ◽

Ionized Gas ◽

Nonthermal Radio ◽

The Galaxy ◽

First Time ◽

Source Structure

The center of our Galaxy contains an extremely compact nonthermal radio source. For the first time, elongation in the source structure has been detected. The long axis is nearly aligned with the minor axis of the Galaxy. Recent high resolution observations of the ionized gas within the central 3 parsecs suggest that matter may be falling in towards the center. This has interesting implications on the processes within our Galactic nucleus.

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G359.3–0.82: An Unusual Radio Source

Symposium - International Astronomical Union ◽

10.1017/s0074180900186541 ◽

1989 ◽

Vol 136 ◽

pp. 197-204

Author(s):

F. Yusef-Zadeh ◽

F. Yusef-Zadeh

Keyword(s):

Radio Emission ◽

Interstellar Medium ◽

Radio Source ◽

Relative Velocity ◽

Galactic Center ◽

Extragalactic Radio Source ◽

Compact Source ◽

Nonthermal Radio ◽

Galactic Object

An unusual radio source exhibiting an axisymmetric, cometary morphology was recently reported by Yusef-Zadeh and Bally (1987) near the Galactic center. This source, G359.3–0.82, consists of a bright head containing a compact source followed by a tail exhibiting sinuous structure. Radio emission is highly polarized and has a nearly flat spectrum between λ6cm and λ20cm. Its location in the sky, spectrum, and lack of resemblance to any other extragalactic radio source suggested to us that this radio source is a Galactic object possibly lying near the Galactic center. New high-reslolution radio images obtained using the VLA confirm the remarkable morphology and strengthen the distinction between G359.3–0.82 and any known extragalactic radio source. The characteristics of G359.3–0.82 suggest that it may be a nonthermal radio wake produced by an object moving through the interstellar medium at a high relative velocity.

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