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Simultaneous X-Ray and Infrared Observations of Sagittarius A*'s Variability.

H Boyce1, D Haggard1,2, G Witzel3,4

  • 1Department of Physics and McGill Space Institute, McGill University, 3600 University St., Montreal QC, H3A 2T8, Canada.

The Astrophysical Journal
|August 25, 2020
PubMed
Summary
This summary is machine-generated.

X-ray flares from Sagittarius A* may precede infrared flares by 10-20 minutes, though the timing is statistically consistent with simultaneity. Further observations are needed to confirm flare timing and emission mechanisms.

Keywords:
Galaxy: centeraccretion, accretion disksblack hole physicsradiation mechanisms: non-thermal

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Area of Science:

  • Astronomy
  • Astrophysics
  • Galactic Center Research

Background:

  • Sagittarius A* exhibits highly variable X-ray and infrared (IR) emission.
  • X-ray flares occur approximately daily, while IR emission is continuously variable.
  • Simultaneous observations suggest IR flux rises coincide with X-ray flares, but not vice-versa.

Purpose of the Study:

  • To characterize simultaneous X-ray/IR events from Sagittarius A*
  • To measure the time lag between X-ray and IR flares
  • To constrain models of Sagittarius A*'s accretion flow and flare emission mechanisms.

Main Methods:

  • Utilized over 100 hours of simultaneous data from the Spitzer Space Telescope and Chandra X-ray Observatory.
  • Analyzed light curves from coordinated observations of Sagittarius A*
  • Performed cross-correlation analysis on the IR and X-ray data.

Main Results:

  • The longest simultaneous IR and X-ray observations of Sagittarius A* to date were analyzed.
  • Cross-correlation suggests X-ray flares may lead IR flares by 10-20 minutes (68% confidence).
  • The 99.7% confidence interval for the time lag includes zero, indicating statistical consistency with simultaneity.

Conclusions:

  • The precise timing relationship between X-ray and IR flares remains statistically uncertain.
  • Longer, simultaneous multi-wavelength observations of bright flares are crucial.
  • Improved constraints on flare timing and emission mechanisms are needed for Galactic Center studies.