Determination of the Cosmic Distance Scale from Sunyaev‐Zel’dovich Effect andChandraX‐Ray Measurements of High‐Redshift Galaxy Clusters

Abstract

We determine the distance to 38 clusters of galaxies in the redshift range 0.14≤z≤0.89 using X-ray data from Chandra and Sunyaev-Zeldovich Effect data from the Owens Valley Radio Observatory and the Berkeley-Illinois-Maryland Association interferometric arrays. The cluster plasma and dark matter distributions are analyzed using a hydrostatic equilibrium model that accounts for radial variations in density, temperature and abundance, and the statistical and systematic errors of this method are quantified. The analysis is performed via a Markov chain Monte Carlo technique that provides simultaneous estimation of all model parameters. We measure a Hubble constant of H 0 = 76.9 ± 3.93.4 ± 10.0 8.0 km s −1 Mpc −1 (statistical followed by systematic uncertainty at 68% confidence) for an Ω M = 0.3, Ω Λ =0.7 cosmology. We also analyze the data using an isothermal β model that does not invoke the hydrostatic equilibrium assumption, and find H 0 = 73.7 ± 4.63.8 ± 9.5 7.6 km s −1 Mpc −1 ; to avoid effects from cool cores in clusters, we repeated this analysis excluding the central 100 kpc from the X-ray data, and find H 0 = 77.6 ± 4.8 4.3 ± 10.1 8.2 km s −1 Mpc −1 (statistical followed by systematic uncertainty at 68% confidence). The consistency between the models illustrates the relative insensitivity of SZE/X-ray determinations of H 0 to the details of the -2cluster model. Our determination of the Hubble parameter in the distant universe agrees with the recent measurement from the Hubble Space Telescope key project that probes the nearby universe.Subject headings: cosmology: cosmic microwave background; cosmology: distance scale; X-rays: galaxies: clusters SZE/X-ray distances provide a measure of the Hubble constant that is independent of the extragalactic distance ladder and probe high redshifts, well into the Hubble flow. The 1 The clusters with t cool ≤ 0.5t Hubble are 2261. The Hubble time is approximately t Hubble ≃ H −1 0 (Carroll, Press and Turner 1992) with H 0 =72 km s −1 Mpc −1 and the cooling time (t cool ≃ 3k B T /2Λ ee n e ) is calculated using the central density and the temperature from an isothermal β model fit.

Improved constraints on violations of the Einstein equivalence principle in the electromagnetic sector with complementary cosmic probes

“…The distance modulusμ 1 (i), µ 2 (i) andμ 3 (i) correspond to weighted averages from the SNe Ia data for each i-galaxy cluster in samples present in Refs. [30,31,35] (see Eq. 50).…”

“…1c is that some objects are not well described by the hydrostatic equilibrium model (see Table 6 in Ref. [31]). They are: Abell 665, ZW 3146, RX J1347.5-1145, MS 1358.4 + 6245, Abell 1835, MACS J1423+2404, Abell 1914, Abell 2163, Abell 2204.…”

“…It is critical to consider different assumptions on the galaxy clusters morphology since the distance depends on the hypotheses considered. In both samples, we have added a conservative 12% of systematic error (see Table 3 in [31]). …”

“…Then, we end up with 40, 29 and 25μ i and σ 2 µi measurements when the sample from [35], [31] and [30] is considered, respectively. Following [32] we added quadratically a 0.15 systematic error to each SNe Ia distance modulus error.…”

“…The authors have used angular diameter distances (ADD) of galaxy clusters obtained via their X-ray surface brightness jointly with observations of the Sunyaev-Zel'dovich effect (SZE) [30,31], SNe Ia samples [32], CMB temperature in different redshifts, T CMB (z) [33,34] and the most recent X-ray gas mass fraction (GMF) data with galaxy clusters in the redshift range 0.078 ≤ z ≤ 1.063 [35]. In the Ref.…”