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Jet Models for Flaring in Sgr A*
Author(s) -
Markoff Sera,
Falcke Heino
Publication year - 2003
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.200385070
Subject(s) - physics , astrophysics , flare , accretion (finance) , supermassive black hole , jet (fluid) , galactic center , particle acceleration , astronomy , synchrotron , thermal , active galactic nucleus , electron , context (archaeology) , galaxy , nuclear physics , mechanics , paleontology , meteorology , biology
Last year, the X‐ray mission Chandra observed a factor of ∼50 flaring in the Galactic Center supermassive black hole candidate Sgr A*. The smallest timescale of ∼600 seconds argues for an origin within ∼40 r g of the central engine, which narrows the source down to the inner regions of either the accretion flow or jet outflows. Because the variability in the radio has never shown similar levels of flaring over its observed history, a simple jump of order 50 in the accretion rate is likely not the cause of the fluctuations. We argue that additional electron heating near the base of a jet can account for the flaring which, depending on the underlying physical mechanism, predicts significantly different simultaneous multi‐wavelength behavior. For the case of direct heating of the thermal electrons by a factor of a few, the flare would be a result of increased synchrotron‐self Compton emission. Non‐thermal particle acceleration, on the other hand, could account for the flare via high‐energy synchrotron emission. We discuss these mechanisms in the context of the jet model, and the respective signatures which would allow us to distinguish between them in future flaring events. We briefly discuss these predictions in light of the newest flare observations.