An X-Ray, Infrared, and Submillimeter Flare of Sagittarius A*

By D. Marrone, F. Baganoff, Mark R. Morris, J. Moran, A. Ghez, S. Hornstein, C. Dowell, D. Muñoz, M. Bautz, G. Ricker and 7 more. 2007

166 citations recorded by the source corpus.

Energetic flares are observed in the Galactic supermassive black hole Sagittarius A* from radio to X-ray wavelengths. On a few occasions, simultaneous flares have been detected in IR and X-ray observations, but clear counterparts at longer wavelengths have not been seen. We present a flare observed over several hours on 2006 July 17 with the Chandra X-Ray Observatory, the Keck II telescope, the Caltech Submillimeter Observatory, and the Submillimeter Array. All telescopes observed strong flare events, but the submillimeter peak is found to occur nearly 100 minutes after the X-ray peak. Submillimeter polarization data show linear polarization in the excess flare emission, increasing from 9% to 17% as the flare passes through its peak, consistent with a transition from optically thick to thin synchrotron emission. The temporal and spectral behavior of the flare require that the energetic electrons responsible for the emission cool faster than expected from their radiative output. This is consistent with adiabatic cooling in an expanding emission region, with X-rays produced through self-Compton scattering, although not consistent with the simplest model of such expansion. We also present a submillimeter flare that followed a bright IR flare on 2005 July 31. Compared to 2006, this event had a larger peak IR flux and similar submillimeter flux, but it lacked measurable X-ray emission. It also showed a shorter delay between the IR and submillimeter peaks. Based on these events we propose a synchrotron and self-Compton model to relate the submillimeter lag and the variable IR/X-ray luminosity ratio.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/52460aadba2f316de7c3deb4d2e0371da21276dd

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IPOLE - semi-analytic scheme for relativistic polarized radiative transport (2017, background): “It is therefore natural that EHT targets have substantial linear polarization, and indeed the linear polarization fraction in Sgr A* is ∼ 7 per cent1 (Bower et al. 2003, 2005; Marrone et al. 2007, 2008) and in M87 it is < 1 per cent (Kuo et al. 2014).”
THE SUBMILLIMETER BUMP IN Sgr A* FROM RELATIVISTIC MHD SIMULATIONS (2010, methodology): “Gravity, 24, 259 Ohsuga, K., Kato, Y., & Mineshige, S. 2005, ApJ, 627, 782 Quataert, E., & Gruzinov, A. 2000, ApJ, 545, 842 Reid, M. J., Broderick, A. E., Loeb, A., Honma, M., & Brunthaler, A. 2008, ArXiv e-prints, astro-ph/0801.4505 Rogers, A. E. E., et al. 1974, ApJ, 193, 293 Schnittman, J. D., Kr”
DETECTING FLARING STRUCTURES IN SAGITTARIUS A* WITH HIGH-FREQUENCY VLBI (2008, result): “…et al. 2000; Bower et al. 2001, 2003; Marrone et al. 2006), and subsequent measurements of the Faraday rotation measure (Macquart et al. 2006; Marrone et al. 2007), the accretion rate near the black hole has been inferred to be significantly less than the Bondi rate, implying the existence…”
Magnetic Reconnection and Hot Spot Formation in Black Hole Accretion Disks (2020, background): “…X-ray and near-infrared flares are detected on roughly a daily basis coming from Sgr A∗, the supermassive black hole in the center of our Galaxy (see e.g., Baganoff et al. 2001; Genzel et al. 2003; Meyer et al. 2008; Marrone et al. 2008; Neilsen et al. 2013; Fazio et al. 2018; Boyce et al. 2019).”