UCSD/CASS Archive of Images & Illustrations: Dark Matter

Composite figure showing the geometry of a microlensing event. The insets show a picture of the Large Magellanic Cloud and the Great Melbourne Telescope in Canberra, Australia where the MACHO Project collected microlensing survey data for eight years. A MACHO in the halo of the Milky Way is shown bending light from a star in the Large Magellanic Cloud on its path to the telescope in Australia.

Three color Hubble Space Telescope-image of LMC-5. We show a three-color composite image of the WFPC2 V, R, and I band images of LMC-5. The microlensing source star is the blue star near the center of the figure which is partially blended with a much redder object (indicated by arrow) displaced by 0.134''. The direction of motion of the lens on the sky derived from the Hubble data (Theta_{HST,sky} = -92 degrees) and the microlensing parallax fit (Theta_{PAR,sky} = -100 degrees) are both shown.

We show a composite European Southern Observatory Very Large Telescope FORS2 spectrum of the LMC-5 source-lens system from 4 x 1500 second exposures on February 2, 2001. The potassium, sodium and titanium oxide features from the lens are marked. The calcium lines are a blend from both the lens and the LMC source star (spectral type F). The presence of KI, NaI, the absence of CsI + RbI and the TiO band at 7100 Angstroms with corresponding absence of the VO band at 7450 Angstroms lead us to conclude that the lens is of spectral type M4-5V. The spectrum has been put on a relative flux scale and smoothed to a resolution of about 3 Angstroms