Program: GS-2008A-Q-79

Until recently theoretical expectation was that magnetic activity would disappaer in fully convective stars (>M5). We now know that magnetic activity in fact exists in late-M and L dwarfs, but the configuration, energy scale, and origin of the field and dynamo remain uncertain. Numerical simulations cannot presently accomodate the conditions in ultracool dwarfs, and progress relies exclusively on observations. Moreover, the shift from persistent emission to flares, which are currently poorly characterized, requires these observations to be simultaneous and broad-band. We were recently awarded Chandra/VLA time to study magnetic activity in L dwarfs. Our previous program, using simultaneous Gemini/Chandra/VLA/Swift observations of M dwarfs (semester 2007A), uncovered unexpected activity patterns and a dramatic shift in the field generation compared to early-type stars. Here we propose to extend our studies to brown dwarfs, and delineate the underlying physics of their magnetic activity with simultaneous GMOS spectroscopy of our approved Chandra/VLA targets.