Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way

Details Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way

2003-09-02

arxiv.org/abs/astro-ph/0309076v2

Astrophys.J.601:L159-L162,2004

Astronomy and Astrophysics

Astrophysics

published in Astrophysical Journal Letters

Scientific paper

10.1086/382024

We report the detection of a variable point source, imaged at L'(3.8 microns) with the W. M. Keck II 10-meter telescope's adaptive optics system, that is coincident to within 18 mas of the Galaxy's central supermassive black hole and the unique radio source Sgr A*. While in 2002 this source (SgrA*-IR) was confused with the stellar source S0-2, in 2003 these two sources are separated by 87 mas allowing the new source's properties to be determined directly. On four separate nights, its observed L' magnitude ranges from 12.2 to 13.8, which corresponds to a flux density of 0.7 - 3 mJy, observed, and 4 - 17 mJy, dereddened; no other source in this region shows such large variations in flux density - a factor of 4 over a week and a factor of 2 over 40 min. In addition, it has a K-L' color greater than 2.1, which is at least 1 mag redder than any other source detected at L' in its vicinity. Based on this source's coincidence with the Galaxy's dynamical center, its lack of motion, its variability, and its red color, we conclude that it is associated with the central supermassive black hole. The short timescale for the 3.8 micron flux density variations implies that the emission arises in the accretion flow on physical size scales smaller than 5 AU, or 80 R_s for a 4x10^6 Mo black hole. We suggest that the 3.8 micron emission and the X-ray flares arise from the same underlying physical process, possibly the acceleration of a small populations of electrons to ultrarelativistic energies. In contrast to the X-ray flares which are only detectable 2% of the time, the 3.8 micron emission provides a new, constantly accessible, window into the physical conditions of the plasma in close proximity to the central black hole.

Affiliated with

Also associated with

No associations

Rating

Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-301507