Refined Dark Matter Determinations from Chandra Observations of Quadruply Lensed Quasars
Abstract
We present a microlensing analysis of Chandra observations of 14 quadruply lensed quasars. X-ray flux measurements of the individual quasar images give a clean determination of the microlensing effects in the lensing galaxy and thus offer a direct assessment of the local fraction of stellar matter making up the total integrated mass along the lines of sight through the lensing galaxy. A Bayesian analysis of the ensemble of lensing galaxies gives a most likely local stellar fraction of 7%, with the other 93% in a smooth, dark matter component, at a mean impact parameter Rc of 6.6 kpc from the center of the lensing galaxy. We divide the systems into smaller ensembles based on Rc and find that the most likely local stellar fraction varies qualitatively and quantitatively as expected, decreasing as a function of Rc.
We gratefully acknowledge support from Chandra grant GO1-12135X.- Publication:
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American Astronomical Society Meeting Abstracts #220
- Pub Date:
- May 2012
- Bibcode:
- 2012AAS...22032102P