Gravitational lensing, time delay, and angular diameter distance

Abstract

view Abstract Citations (40) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Gravitational Lensing, Time Delay, and Angular Diameter Distance Narayan, Ramesh Abstract Combining a model of the mass distribution in the gravitational lens Q0957 + 561 with measurements of the velocity dispersion of the primary lensing galaxy and the time delay between the two images, the Hubble constant has been recently estimated to be H_0_=37+/-14 km s^-1^ Mpc^-1^ The result depends weakly on the assumed value of q_0_ and may have systematic errors due to nonuniqueness of the model. It is shown here that the quantity that is most directly measured using a gravitational lens system is not H_0_ but rather the angular diameter distance d_oL_ from the observer to the lens. The determination of d_oL_ requires neither a knowledge of the distance to the source nor any cosmological assumption other than local isotropy and homogeneity transverse to the line of sight, again with possible systematic effects. In the case of Q0957 + 561, where the lens is at a redshift of Z_L_=0.36, the result is d_oL_ = 1700 +/- 600 Mpc. If the mass distribution of the cluster surrounding the primary lens in Q0957 + 561 can be determined through independent observations, then it may be possible to estimate both H_0_ and q_0_. Publication: The Astrophysical Journal Pub Date: September 1991 DOI: 10.1086/186129 Bibcode: 1991ApJ...378L...5N Keywords: Dark Matter; Distance; Galaxies; Gravitational Lenses; Hubble Constant; Time Lag; Cosmology; Diameters; Mass Distribution; Astrophysics; COSMOLOGY; DARK MATTER; GALAXIES: DISTANCES; GRAVITATIONAL LENSES full text sources ADS | data products SIMBAD (3)