Seminar

G2 as a Probe of Sgr A*s Hot Environs: A View from Chandra and VLA

The recent discovery of a dense, cold cloud (dubbed "G2") approaching the SMBH at our Galactic Center offers an unprecedented opportunity to test models of black hole accretion and its associated feedback. G2's orbit is eccentric and the cloud already shows signs of tidal disruption by the black hole. High-energy emission from the Sgr A*/G2 encounter will likely rise toward pericenter (mid-to-late 2013, or early 2014) and continue over the next several years as the material circularizes. This encounter is also likely to enhance Sgr A*'s flare activity across the electromagnetic spectrum. We present preliminary results from our 2013 joint Chandra/VLA monitoring campaigns (>400 ks from Chandra and ~30 hours from VLA). Our programs aim to study the radiation properties of Sgr A* as G2 breaks up and feeds the accretion flow, to constrain the rates and emission mechanisms of faint X-ray flares, and to detect G2 itself as it is shocked and heated. Meanwhile, the appearance of a new magnetar (SGR J174540.2-290029, 2.4 arcsec from Sgr A*) and an outburst from a transient LMXB (CXO J174540.0-290005) are yielding additional exciting science. We discuss the constraints these data place on theoretical models for the Sgr A*/G2 encounter and outline plans for continued monitoring with Chandra, XMM, HST, and VLA in 2014.

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