Microlensing results toward the galactic bulge, theory of fitting blended light curves, and discussion of weak lensing corrections

Details Microlensing results toward the galactic bulge, theory of fitting blended light curves, and discussion of weak lensing corrections Microlensing results toward the galactic bulge, theory of fitting blended light curves, and discussion of weak lensing corrections

Jun 2006

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006phdt.........4t&link_type=abstract

PhD Thesis, Proquest Dissertations And Theses 2006. Section 0033, Part 0606 191 pages; [Ph.D. dissertation].United States -- Cal

Other

4

Galactic Bulge, Light Curves, Weak Lensing, Microlensing

Scientific paper

Analysis and results (Chapters 2-5) of the full 7 year Macho Project dataset toward the Galactic bulge are presented. A total of 450 high quality, relatively large signal-to-noise ratio, events are found, including several events exhibiting exotic effects, and lensing events on possible Sagittarius dwarf galaxy stars. We examine the problem of blending in our sample and conclude that the subset of red clump giants are minimally blended. Using 42 red clump giant events near the Galactic center we calculate the optical depth toward the Galactic bulge to be t = [Special characters omitted.] × 10 -6 at ( l, b ) = ([Special characters omitted.] ) with a gradient of (1.06 ± 0.71) × 10 -6 deg -1 in latitude, and (0.29±0.43) × 10 -6 deg -1 in longitude, bringing measurements into consistency with the models for the first time.
In Chapter 6 we reexamine the usefulness of fitting blended light-curve models to microlensing photometric data. We find agreement with previous workers (e.g. Wozniak & Paczynski) that this is a difficult proposition because of the degeneracy of blend fraction with other fit parameters. We show that follow-up observations at specific points along the light curve (peak region and wings) of high magnification events are the most helpful in removing degeneracies.
We also show that very small errors in the baseline magnitude can result in problems in measuring the blend fraction, and study the importance of non- Gaussian errors in the fit results. The biases and skewness in the distribution of the recovered blend fraction is discussed. We also find a new approximation formula relating the blend fraction and the unblended fit parameters to the underlying event duration needed to estimate microlensing optical depth.
In Chapter 7 we present work-in-progress on the possibility of correcting standard candle luminosities for the magnification due to weak lensing. We consider the importance of lenses in different mass ranges and look at the contribution from lenses that could not be observed. We conclude that it may be possible to perform this correction with relatively high precision (1-2%) and discuss possible sources of error and methods of improving our model.

Affiliated with

Also associated with

No associations

Rating

Microlensing results toward the galactic bulge, theory of fitting blended light curves, and discussion of weak lensing corrections 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 results toward the galactic bulge, theory of fitting blended light curves, and discussion of weak lensing corrections, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Microlensing results toward the galactic bulge, theory of fitting blended light curves, and discussion of weak lensing corrections will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1476588