The Mass, Baryonic Fraction, and X‐Ray Temperature of the Luminous, High‐Redshift Cluster of Galaxies MS 0451.6−0305

Abstract

We present new Chandra X-ray observations of the luminous and cosmologicallysignificant X-ray cluster of galaxies, MS0451.6-0305, at z = 0.5386. Spectral imaging data for the cluster are consistent with an isothermal cluster of (10.0 − 10.6) ± 1.6 keV, with an intracluster Fe abundance of (0.32−0.40)±0.13 solar. The systematic uncertainties, arising from calibration and model uncertainties, of the temperature determination are nearly the same size as the statistical uncertainties, since the time-dependent correction for absorption on the detector is uncertain for these data. We discuss the effects of this correction on the spectral fitting. The effects of statistics and fitting assumptions of 2-D models for the X-ray surface brightness are thoroughly explored. This cluster appears to be elongated and so we quantify the effects of assuming an ellipsoidal gas distribution on the gas mass and the total gravitating mass estimates. These data are also jointly fit with previous Sunyaev-Zel'dovich observations to obtain an estimate of the cluster's distance (D A = 1219 +340 −288 ± 387 Mpc, statistical followed by systematic uncertainties) assuming spherical symmetry. If we, instead, assume a Hubble constant, All of the processing, calibration, and much of the analysis and extraction of the X-ray data were done with Chandra Interactive Analysis of Observations (CIAO) v2.2.1 and v2.2.3 packages 2 along with the calibration database (CALDB) available from the Chandra X-ray Center (CXC); spectra were analyzed with the XSPEC 3 v11.1 (Arnaud 1996). For this paper, the names of the CIAO packages will be italicized. Since the interpretation of X-ray data depends on the maturity of the calibration, we report version numbers when available and release dates otherwise.The name of the original processing implemented by the CXC was R4CU5UPD11, so we reprocessed the Level 1 event files with the gain files from CALDB v2.10 using acis process events with the appropriate bad pixel files. The level 1 events were filtered with the standard good time intervals supplied by the pipeline, and then filtered to admit only ASCA grades 0, 2, 3, 4, and 6, and "clean" status (= 0) events. The plate scale for the unbinned data is 0. ′′ 4920 per detector pixel. The aspect for this observation required a very small correction of ∆RA = −0.63 ′′ and ∆Dec = −0.58 ′′ . A typical absolute astrometric uncertainty in a Chandra ACIS-S observation is about 1.0 ′′ but it can be as large as 3.0 ′′ relative to astrometric standards in the International Celestial Reference Frame (ICRS) and Hipparcos (the Tycho2 catalog). 4Spectral analysis was performed in Pulse Invariant (PI) space (i.e., after the instrument gains 2

Disentangling a group of lensed submm galaxies at z∼ 2.9

“…if we only consider systems exactly like we found, then the probability would be arbitrarily small), we can carry out a crude estimate as follows. The MS0451 cluster has a mass of around 10 15 M (Donahue et al 2003) and an Einstein radius of around 30 arcsec. Conservatively taking 3 × 10 14 M as the limit for rich clusters, surveys (like the Planck catalogue of Sunyaev-Zeldovich sources; Planck Collaboration XXIX 2013) suggest that there are around 2000 such clusters on the sky, and hence the sum of the areas covered by their Einstein radii (where strong lensing is possible) is about 10 −5 of the sky.…”

A CENSUS OF MID-INFRARED-SELECTED ACTIVE GALACTIC NUCLEI IN MASSIVE GALAXY CLUSTERS AT 0 ≲z≲ 1.3

“…This reduces the scatter in mid-IR color due to star formation for members. X-ray data have shown that the distribution of the cluster ICM is predominantly elliptical (Donahue et al 2003) and the redshift distribution of cluster galaxies is broadly Gaussian (Moran et al 2007a). This indicates that MS 0451 is predominantly virialized with no substantial infalling galaxies.…”

DeepXMM‐NewtonandChandraObservations of Cl J1226.9+3332: A Detailed X‐Ray Mass Analysis of az= 0.89 Galaxy Cluster

“…However, the low X-ray fluxes of typical high-redshift clusters make the observing time needed to meet these requirements prohibitive. Sufficiently deep observations for clusters at z > 0:5 are very rare (e.g., Jeltema et al 2001;Arnaud et al 2002;Donahue et al 2003;Maughan et al 2004b); for most clusters at high redshifts, masses must be estimated from observed global properties such as X-ray luminosity and temperature. The scaling relations between cluster properties at high redshifts are then of key importance, and their uncertainty is a dominant contributor to the error budget of derived cosmological parameters (Henry 2004).…”