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arxiv: astro-ph/0211385 · v1 · submitted 2002-11-17 · 🌌 astro-ph

Quasar Parallax: a Method for Determining Direct Geometrical Distances to Quasars

Martin Elvis , Margarita Karovska (Harvard-Smithsonian Center for Astrophysics) This is my paper
classification 🌌 astro-ph
keywords distanceslambdamethodquasarsangularbelrdiameterdirect
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We describe a novel method to determine direct geometrical distances to quasars that can measure the cosmological constant, Lambda, with minimal assumptions. This method is equivalent to geometric parallax, with the `standard length' being the size of the quasar broad emission line region (BELR) as determined from the light travel time measurements of reverberation mapping. The effect of non-zero Lambda on angular diameter is large, 40% at z=2, so mapping angular diameter distances vs. redshift will give Lambda with (relative) ease. In principle these measurements could be made in the UV, optical, near infrared or even X-ray bands. Interferometers with a resolution of 0.01mas are needed to measure the size of the BELR in z=2 quasars, which appear plausible given reasonable short term extrapolations of current technology.

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Cited by 2 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Redshift-Dependent Intrinsic Dispersion in the Quasar UV/X-ray Luminosity Relation

    astro-ph.CO 2026-06 unverdicted novelty 5.0

    Intrinsic dispersion in the quasar UV/X-ray luminosity relation decreases with redshift above z~1.6 and modeling it as redshift-dependent shifts Omega_m0 by ~0.025 in flat LambdaCDM.

  2. Deep Learning Calibration of the Quasar X-ray/UV Luminosity Relation for Cosmological Applications

    astro-ph.CO 2026-06 unverdicted novelty 4.0

    Quasar X-ray/UV luminosity relation shows non-linear redshift dependence that cannot be fixed by linear correction and requires further modeling or data screening for cosmological use.