AAS 205th Meeting, 9-13 January 2005
Session 11 Brown Dwarfs and Exoplanets
Poster, Monday, January 10, 2005, 9:20am-6:30pm, Exhibit Hall

## [11.08] A deep look at our nearest brown dwarf, \epsilon Ind B, in X-rays and radio

M. Audard (Columbia Astrophysics Lab), A. Brown (CASA/University of Colorado), J.E. Gizis (University of Delaware), M. Güdel, K.R. Briggs, A. Telleschi (Paul Scherrer Institut)

In early December 2004, Chandra and the Australian Telescope Compact Array will observe the nearest brown dwarf, \epsilon Ind B, in X-rays and in the radio, respectively. We will present the first results of this simultaneous campaign. \epsilon Ind B consists of a pair of T1+T6 brown dwarfs at a distance of 3.6 parsecs. Our 70 ks-long X-ray observation will reach down to \log L\rm X/L\rm bol = -4.9 and -4.2 for the T1 and T6 components, respectively, whereas the ATCA should reach ~20 \muJy/beam at 4.8 and 8.6 GHz in its 6D array configuration. Brown dwarfs are very cool (T\rm eff ~1000 K for a T-type brown dwarf) and, therefore, they have predominantly neutral photospheres. Signatures of magnetic activity is thus not expected. Nevertheless, H\alpha and radio detections of L-type brown dwarfs have been reported (no detection of a L/T brown dwarf has been reported in X-rays yet). The detection of a T-type brown dwarf in the radio and X-ray regimes can open a new window to the study of magnetic activity beyond the main sequence.

M.A. acknowledges support from SAO grant GO4-5002X.

Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.