| Description |
Coordinated study of flare emission from Sgr A*, the closest supermassive
black hole, reveals information about the hydrodynamics, energetics, and
accretion behavior of matter within the innermost ten Schwarzschild radii.
We propose to use the unique capability of Herschel/SPIRE and XMM in order
to characterize flare emission simultaneously at many different wavelengths,
the most important of which are completely unavailable from the ground.
These measurements will explore the nature of emission at the peak of the
spectrum of Sgr A* and will determine the transition wavelength at which the
variable emission becomes optically thin. In particular, we will test the
prediction that there will be time delay between X-ray flares and the peak
emission at 250, 350, and 500 microns. We will take advantage of the
calibration stability of Herschel resulting from the L2 placement to detect
Sgr A* in SPIRE difference images. The proposed Herschel and XMM
observations form the cornerstone of a multi-wavelength campaign that
includes observations in near-IR and radio wavelengths. The cross
correlation of flare emission at multiple wavelengths will have far-reaching
implications for testing the emission mechanism of Sgr A* and for
understanding the processes of accretion onto and outflow from the closest
supermassive black hole. Lastly, a long flux monitoring of Sgr A* with
Herschel over long and nearly continuous baselines will characterize the
fraction of time that Sgr A* is active in submm wavelengths and will provide
a legacy to unravel the key properties of the best example of a
low-luminosity massive black hole. |
