A DETERMINATION OF THE HUBBLE CONSTANT USING MEASUREMENTS OF X-RAY EMISSION AND THE SUNYAEV-ZELDOVICH EFFECT AT MILLIMETER WAVELENGTHS IN THE CLUSTER ABELL 1835

摘要

We present a determination of the Hubble constant and central electron density in the cluster Abell 1835 (z = 0.2523) from measurements of X-ray emission and millimeter-wave observations of the Sunyaev-Zeldovich (S-Z) effect with the Sunyaev-Zeldovich Infrared Experiment (SuZIE) multifrequency array receiver. Abell 1835 is a well studied cluster in the X-ray with a large central cooling flow. Using a combination of data from ROSAT PSPC and HRI images and millimeter wave measurements we fit a King model to the emission from the ionized gas around Abell 1835 with θ_0 = 0.22′ ± 0.02′ and β = 0.58 ± 0.02. Assuming the cluster gas to be isothermal with a temperature of 9.8_(-1.3)~(+2.3) keV, we find a y-parameter of 4.9 ± 0.6 x 10~(-4) and a peculiar velocity of 500 ± 1000 km s~(-1) from measurements at three frequencies, 145, 221, and 279 GHz. Combining the S-Z measurements with X-ray data, we determine a value for the Hubble constant of H_0 = 59_(-28)~(+38) km s~(-1) Mpc~(-1) and a central electron density for Abell 1835 of n_(e0) = 5.64_(-1.02)~(+1.61) X 10~(-2) cm~(-3) assuming a standard cosmology with Ω_m = 1 and Ω_Λ = 0. The error in the determination of the Hubble constant is dominated by the uncertainty in the temperature of the X-ray emitting cluster gas.