Re-examination of the possible tidal stream in front of the LMC

It has recently been suggested that the stars in a vertical extension of the red clump feature seen in LMC color-magnitude diagrams could belong to a tidal stream of material located in front of that galaxy. If this claim is correct, this foreground concentration of stars could contribute significantly to the rate of gravitational microlensing events observed in the LMC microlensing experiments. Here we present radial velocity measurements of stars in this so-called “vertical red clump” (VRC) population. The observed stellar sample, it transpires, has typical LMC kinematics. It is shown that it is improbable that an intervening tidal stream should have the same distribution of radial velocities as the LMC, which is consistent with an earlier study that showed that the VRC feature is more likely a young stellar population in the main body of that galaxy. However, the kinematic data do not discriminate against the possibility that the VRC is an LMC halo population. Subject headings: galaxies: individual (Large Magellanic Cloud) — Galaxy: halo European Southern Observatory Karl Schwarzschild Straße 2, D-85748 Garching bei München, Germany Electronic mail: [email protected] Fellow of the Pacific Institute for Mathematical Sciences 1998-1999, Dept. of Physics and Astronomy, University of Victoria, Victoria, B.C., Canada & Astronomy Dept., University of Washington, Seattle WA, U.S.A. Electronic mail: [email protected] Electronic mail: [email protected] Kapteyn Astronomical Institute 9700 AV Groningen, The Netherlands Electronic mail: [email protected]