A power-law break in the near-infrared power spectrum of the Galactic center black hole

Understand

Proposed scaling relations of a characteristic timescale in the X-ray power spectral density of galactic and supermassive black holes have been used to argue that the accretion process is the same for small and large black holes.

• Here, we report on the discovery of this timescale in the near-infrared radiation of Sgr A*, the 4x10^6 solar mass black hole at the center of our Galaxy, which is the most extreme sub-Eddington source accessible to observations.
• Previous simultaneous monitoring campaigns established a correspondence between the X-ray and near-infrared regime and thus the variability timescales are likely identical for the two wavelengths.
• We combined Keck and VLT data sets to achieve the necessary dense temporal coverage, and a time baseline of four years allows for a broad temporal frequency range.