Multiwavelength Light Curves of Two Remarkable Sagittarius A* Flares

2018/07/19 by G. G. Fazio, J. L. Hora, Joseph L. Hora +24
Engineering · Physics and Astronomy · #Accretion (finance) #Active galactic nucleus #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Black hole (networking) #Flare #Flux (metallurgy) #Galactic Center #Galaxy #Mechanics and Biomechanics Studies #Milky Way #Physics #Sagittarius A* #Star formation #Submillimeter Array #Supermassive black hole #astro-ph.HE

paper · pdf · doi:10.3847/1538-4357/aad4a2

9 pages, 3 figures, to appear in the Astrophysical Journal

arxiv created 2018/07/19 · openalex publication_date 2018/08/30 · arxiv updated 2018/09/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06

Abstract

Sgr A*, the supermassive black hole (SMBH) at the center of our Milky Way Galaxy, is known to be a variable source of X-ray, near-infrared (NIR), and submillimeter radiation and therefore a prime candidate to study the electromagnetic radiation generated by mass accretion flow onto a black hole and/or a related jet. Disentangling the power source and emission mechanisms of this variability is a central challenge to our understanding of accretion flows around SMBHs. Simultaneous multiwavelength observations of the flux variations and their time correlations can play an important role in obtaining a better understanding of possible emission mechanisms and their origin. This paper presents observations of two flares that both apparently violate the previously established patterns in the relative timing of submillimeter/NIR/X-ray flares from Sgr A*. One of these events provides the first evidence of coeval structure between NIR and submillimeter flux increases, while the second event is the first example of the sequence of submillimeter/X-ray/NIR flux increases all occurring within ~1 hr. Each of these two events appears to upend assumptions that have been the basis of some analytic models of flaring in Sgr A*. However, it cannot be ruled out that these events, even though unusual, were just coincidental. These observations demonstrate that we do not fully understand the origin of the multiwavelength variability of Sgr A* and show that there is a continued and important need for long-term, coordinated, and precise multiwavelength observations of Sgr A* to characterize the full range of variability behavior.

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