Microlensing by the Galactic Bar

Details Microlensing by the Galactic Bar Microlensing by the Galactic Bar

1994-09-11

arxiv.org/abs/astro-ph/9409022v2

Astrophys.J. 440 (1995) L13

Astronomy and Astrophysics

Astrophysics

15 pages, 2 figures

Scientific paper

10.1086/187749

We compute the predicted optical depth and duration distribution of microlensing events towards Baade's window in a model composed of a Galactic disk and a bar. The bar model is a self-consistent dynamical model built out of individual orbits that has been populated to be consistent with the COBE maps of the Galaxy and kinematic observations of the Bulge. We find most of the lenses are at 6.25 kpc in BW. The microlensing optical depth of a 2E10 Msun bar plus a truncated disk is (2.2+-0.3)E-6, consistent with the very large optical depth (3.2+-1.2)E-6 found by Udalski et al. (1994). This prediction doubles that of axisymmetric models by Kiraga and Paczynski (1994) since the bar is elongated along the line-of-sight. The large Einstein radius and small transverse velocity dispersion also predict a longer event duration in the bar model than the KP model. The event rate and duration distribution also depend on the lower mass cutoff of the lens mass function. With a 0.1Msun cutoff, 5-7 events of typical 20 days duration are expected for the OGLE experiment according to our model, while Udalski et al. observed 9 events with durations from 8-62 days. On the other hand, if most of the lenses are brown dwarfs, our model predicts too many short duration events; a KS test finds only 7% probability for the model with 0.01Msun cutoff to be consistent with current data.

Affiliated with

Also associated with

No associations

Rating

Microlensing by the Galactic Bar does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Microlensing by the Galactic Bar, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Microlensing by the Galactic Bar will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-342993