H_0 from gravitational lenses: recent results

dc.creatorSchechter, Paul L.
dc.date2000-09-04
dc.date.accessioned2026-07-25T17:52:27Z
dc.descriptionThe 0th, 1st and 2nd derivatives of a ``Fermat potential'' give the three D's of gravitational lensing: delay, deflection and distortion. Observations of these delays, deflections and distortions for doubly and quadruply imaged quasars give estimates of Hubble's constant, H_0. The single largest contribution to the uncertainty in H_0 arises from the difficulty in constraining the degree of central concentration of the lensing potential. Fortunately, astronomers have spent a good deal of effort over the past quarter century addressing just this question. If galaxies at z=0.5 are like nearby galaxies, the associated systematic uncertainty in H_0 is less than 10%. The expected lens-to-lens scatter is 20%. Results from three particularly well constrained systems are reported.
dc.description10 pages, no figures, uses newpasp.sty, invited review to be published in IAU Symposium No. 201: New Cosmological and the Values of the Fundamental Parameters, eds. A.N. Lasenby and A. Wilkinson
dc.identifierhttps://arxiv.org/abs/astro-ph/0009048
dc.identifierhttp://arxiv.org/abs/astro-ph/0009048
dc.identifier.urihttps://dspace.dare.co.zw/handle/123456789/51449
dc.subjectAstrophysics
dc.titleH_0 from gravitational lenses: recent results
dc.typetext

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