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

Abstract

We present a determination of the Hubble constant and central electrondensity in the cluster Abell 1835 ( z = 0.2523) from measurementsof 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 clusterin the X-ray with a large central cooling flow. Using a combinationof data from ROSAT PSPC and HRI images and millimeter wave measurementswe fit a King model to the emission from the ionized gas around Abell1835 with θ 0 = 0 ##IMG## [http://ej.iop.org/icons/Entities/farcm.gif]{farcm} 22 ± 0 ##IMG## [http://ej.iop.org/icons/Entities/farcm.gif]{farcm} 02 and β = 0.58 ± 0.02. Assuming the cluster gas to beisothermal with a temperature of 9.8 ##IMG## [http://ej.iop.org/images/0004-637X/538/2/505/img1.gif]{img1.gif} keV, we find a y -parameter of 4.9 ± 0.6 × 10 -4 anda peculiar velocity of 500 ± 1000 km s -1 from measurements at threefrequencies, 145, 221, and 279 GHz. Combining the S-Z measurementswith X-ray data, we determine a value for the Hubble constant ofH 0 = 59 ##IMG## [http://ej.iop.org/images/0004-637X/538/2/505/img2.gif]{img2.gif} km s -1 Mpc -1 and a central electron density for Abell1835 of n e 0 = 5.64 ##IMG## [http://ej.iop.org/images/0004-637X/538/2/505/img3.gif]{img3.gif} × 10 -2 cm -3 assuming a standard cosmology with Ω m= 1 and Ω Λ = 0. The error in the determination of the Hubble constantis dominated by the uncertainty in the temperature of the X-ray emittingcluster gas.