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Constraints on H_0 from the Central Velocity Dispersions of Lens Galaxies

Aaron J. Romanowsky·Christopher S. Kochanek
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Abstract

We employ Schwarzschild's method of orbit modeling to constrain the mass profiles of the central lens galaxies in Q0957+561 and PG 1115+080. We combine the measured central projected stellar velocity dispersions of these galaxies with the self-similar radial profiles of the rms velocity and of the Gauss-Hermite moment h_4 observed in nearby galaxies for 0 < R < 2 R_eff. For Q0957+561, we find a 16% uncertainty in the galaxy mass, and formal 2-sigma limits on the Hubble constant of H_0 = (61 +13/-15) km/s/Mpc. For PG 1115+080, we find that none of the viable lens models can be ruled out, so that H_0 is not yet strongly constrained by this system.

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Aaron J. Romanowsky, Christopher S. Kochanek. 1998-11-21. Constraints on H_0 from the Central Velocity Dispersions of Lens Galaxies. https://doi.org/10.1086/307077

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