Short-term variability of Sgr A* Journal Article uri icon



  • AbstractObservations of Sgr A* over the past 4 years with the Keck Telescope in the near-infrared, coupled with millimeter and submillimeter observations, show that the 3.7×106MGalactic Black Hole, Sagittarius A*, displays continuous variability at all these wavelengths, with the variability power concentrated on characteristic time scales of a few hours, and with a variability fraction that increases with wavelength. We review the observations indicating that the few-hour time scale for variability is reproduced at all accessible wavelengths. Interpreted as a dynamical time, this time scale corresponds to a radial distance of 2 AU, or ∼25 Schwarzschild radii. Searches for quasi-periodicities in the near-infrared data from the Keck Telescope have so far been negative. One interpretation of the character of these variations is that they result from a recurring disk instability, rather than from variations in the mass accretion rate flowing through the outer boundary of the emission region. However, neither a variable accretion rate nor a mechanism associated with a jet can presently be ruled out.

publication date

  • August 1, 2006

has restriction

  • bronze

Date in CU Experts

  • November 6, 2020 5:12 AM

Full Author List

  • Morris MR; Hornstein SD; Ghez AM; Lu JR; Matthews K; Baganoff FK

author count

  • 6

Other Profiles

International Standard Serial Number (ISSN)

  • 1743-9213

Electronic International Standard Serial Number (EISSN)

  • 1743-9221

Additional Document Info

start page

  • 195

end page

  • 200


  • 2


  • S238