Is the X-ray variable source in M82 due to gravitational lensing ?

Da-Ming Chen

Published 2001-06-05Version 1

We explore the possibility of attributing the recent discovery of the hard X-ray variable source CXOM82 J095550.2+694047 in M82 to the gravitational magnification by an intervening stellar obeject along the line of sight as microlens. The duration of the event ($>84$ days) allows us to set robust constraints on the mass and location of the mircolensing object when combined with the dynamical properties of the Galactic halo, the M82 and typical globular clusters. Except for the extremely low probablity, the microlensing magnification by MACHO in either the Galactic halo or the M82 halo is able to explain the X-ray variability of CXOM82 J095550.2+694047. It is hoped that the lensing hypothesis can be soon tested by the light curve measurement.