H-alpha line strength of EROS-BLG-2000-5

The red points in the chart are the nightly averages of the strength of the H-alpha absorption line as measured before (point to the left) and during the second caustic crossing. The fully drawn lines represent the expected change, according to two different simulations of the event. The models agree with the data in their general form, but differ on the last night when the trailing limb was crossing the caustic. The two simulations shown differ in their assumptions about the geometry of the event; further data and modeling are now refining these assumptions so that a more quantitative comparison can be made.