Gemini Preprint #64

The Infrared Surface Brightness Fluctuation Hubble Constant

Joseph B. Jensen
Gemini Observatory Northern Operations Center, 670 N. A'ohoku Place, Hilo HI 96720

John L. Tonry
Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822

Rodger I. Thompson
Steward Observatory, University of Arizona, Tucson, AZ 85721

Edward A. Ajhar and Tod R. Lauer
National Optical Astronomical Observatories, P.O. Box 26732, Tucson, AZ 85726

Marcia J. Rieke
Steward Observatory, University of Arizona, Tucson, AZ 85721

Marc Postman
Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218

Michael C. Liu
Department of Astronomy, University of California, Berkeley, CA 94720


We measured infrared surface brightness fluctuation (SBF) distances to an isotropically-distributed sample of 16 distant galaxies with redshifts reaching 10,000 km s-1 using the near-IR camera and multi-object spectrometer (NICMOS) on the Hubble Space Telescope (HST). The excellent spatial resolution, very low background, and brightness of the IR fluctuations yielded the most distant SBF measurements to date. Twelve nearby galaxies were also observed and used to calibrate the F160W (1.6 µm) SBF distance scale. Of these, three have Cepheid variable star distances measured with HST and eleven have optical I-band SBF distance measurements. A distance modulus of 18.5 mag to the Large Magellanic Cloud was adopted for this calibration. We present the F160W SBF Hubble diagram and find a Hubble constant H0=72±2.3 km s-1 Mpc-1 consistent with the data. This 6% decrease in the Hubble constant is consistent with the hypothesis that the Local Group inhabits an under-dense region of the universe, but is also consistent with the best-fit value of H0=76 km s-1 Mpc-1 at the 1.5-sigma level.

To appear in the Astrophysical Journal.

Download the PostScript or PDF file.

Ruth A. Kneale / / November 28, 2000