Gemini Preprint #38

The Infrared Surface Brightness Fluctuation Distances to the Hydra and Coma Clusters

J.B. Jensen
Gemini 8m Telescopes Project, 670 A'Ohoku Place, Hilo HI 96720

J.L. Tonry and G.A. Luppino
Institute for Astronomy, University of Hawaii. 2680 Woodlawn Drive, Honolulu HI 96822


We present IR surface brightness fluctuation (SBF) distance measurements to NGC 4889 in the Coma cluster and to NGC 3309 and NGC 3311 in the Hydra cluster. We explicitly corrected for the contributions to the fluctuations from globular clusters, background galaxies, and residual background variance. We measured a distance of 85±10 Mpc to NGC 4889 and a distance of 46±5 Mpc to the Hydra cluster. Adpoting recession velocities of 7186±428 km s^-1 for Coma and 4054±296 km s^-1 for Hydra gives a mean Hubble constant of Hsubscript 0 = 87±11 km s^-1 Mpc^-1. Corrections for residual variances were a significant fraction of the SBF signal measured, and, if underestimated, would bias our measurement towards smaller distances and larger values of Hsubscript 0. Both NICMOS on the Hubble Space Telescope and large-aperture ground-based telescopes with new IR detectors will make accurate SBF distance measurements possible to 100 Mpc and beyond.

Appears in the Astrophysical Journal.

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Ruth A. Kneale / / August 17, 1998