Статья

A 3% SOLUTION: DETERMINATION OF THE HUBBLE CONSTANT WITH THE<i>HUBBLE SPACE TELESCOPE</i>AND WIDE FIELD CAMERA 3

Adam G. RiessDepartment of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA; [email protected]Lucas M. MacriGeorge P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics & Astronomy, Texas A&M University, 4242 TAMU, College Station, TX 77843-4242, USAStefano CasertanoSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USAHubert LampeitlInstitute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 3FX, UKHenry C. FergusonSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USAA. V. FilippenkoDepartment of Astronomy, University of California, Berkeley, CA 94720-3411, USASaurabh W. JhaDepartment of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854, USAWeidong LiDepartment of Astronomy, University of California, Berkeley, CA 94720-3411, USAR. ChornockHarvard/Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA

2011en

ABI

Аннотация

We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope to determine the Hubble constant (H0) from optical and infrared observations of over 600 Cepheid variables in the host galaxies of 8 recent Type Ia supernovae (SNe Ia), providing the calibration for a mag-z relation of 253 SNe Ia. Increased precision over past measurements comes from: (1) more than doubling the number of infrared observations of Cepheids in nearby SN hosts; (2) increasing the sample of ideal SN Ia calibrators from six to eight; (3) increasing by 20% the number of Cepheids with infrared observations in the megamaser host NGC 4258; (4) reducing the difference in the mean metallicity of the Cepheid comparison samples from Δlog [O/H] = 0.08 to 0.05; and (5) calibrating all optical Cepheid colors with one camera, WFC3, to remove cross-instrument zero-point errors. Uncertainty in H0 from beyond the 1st rung of the distance ladder is reduced from 3.5% to 2.3%. The measurement of H0 via the geometric distance to NGC 4258 is 74.8 \pm 3.1 km s- 1 Mpc-1, a 4.1% measurement including systematics. Better precision independent of NGC 4258 comes from two alternative Cepheid absolute calibrations: (1) 13 Milky Way Cepheids with parallaxes and (2) 92 Cepheids in the Large Magellanic Cloud with multiple eclipsing binary distances, yielding 74.4 \pm 2.5 km s- 1 Mpc-1, a 3.4% uncertainty with systematics. Our best estimate uses all three calibrations but a larger uncertainty afforded from any two: H0 = 73.8 \pm 2.4 km s- 1 Mpc-1 including systematics, a 3.3% uncertainty. The improvement in H0, combined with WMAP7yr data, results in a constraint on the EOS parameter of dark energy of w = -1.08 \pm 0.10 and Neff = 4.2 \pm 0.7 for the number of relativistic species in the early universe. It also rules out the best-fitting gigaparsec-scale void models, posited as an alternative to dark energy. (abridged)

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Идентификаторы

DOI: 10.1088/0004-637x/730/2/119

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Цитирований: 4Использованных источников: 0

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