56146236
The XMM-BCS galaxy cluster survey: I. The X-ray selected cluster catalog from the initial 6 deg$^2$
The XMM-Newton - Blanco Cosmology Survey project (XMM-BCS) is a coordinated X-ray, optical and mid-infrared cluster survey in a field also covered by Sunyaev-Zel dovich effect (SZE) surveys by the South Pole Telescope and the Atacama Cosmology Telescope. The aim of the project is to study the cluster population in a 14 deg{sup 2} field (center: {alpha} {approx} 23:29:18.4, {delta} {approx} -54:40:33.6). The uniform multi-wavelength coverage will also allow us for the first time to comprehensively compare the selection function of the different cluster detection approaches in a single test field and perform a cross-calibration of cluster scaling relations. In this work, we present a catalog of 46 X-ray selected clusters from the initial 6 deg{sup 2} survey core.We describe the XMM-BCS source detection pipeline and derive physical properties of the clusters. We provide photometric redshift estimates derived from the BCS imaging data and spectroscopic redshift measurements for a low redshift subset of the clusters. The photometric redshift estimates are found to be unbiased and in good agreement with the spectroscopic values. Our multi-wavelength approach gives us a comprehensive look at the cluster and group population up to redshifts z {approx} 1. The median redshift of the sample is 0.47more » and the median mass M{sub 500} {approx} 1 x 10{sup 14} M{sub {circle_dot}} ({approx} 2 keV). From the sample, we derive the cluster log N - log S using an approximation to the survey selection function and find it in good agreement with previous studies. We compare optical mass estimates from the Southern Cosmology Survey available for part of our cluster sample with our estimates derived from the X-ray luminosity. Weak lensing masses available for a subset of the cluster sample are in agreement with our estimates. Optical masses based on cluster richness and total optical luminosity are found to be significantly higher than the X-ray values. The present results illustrate the excellent potential of medium-deep, X-ray surveys to deliver cluster samples for cosmological modelling. In combination with available multi-wavelength data in optical, near-infrared and SZE, this will allow us to probe the dependence of the selection functions on relevant cluster observables and provide thus an important input for upcoming large-area multi-wavelength cluster surveys.« less
13992842
Proposed method for searches of gravitational waves from PKS 2155-304 and other blazar flares
We propose to search for gravitational waves from PKS 2155-304 as well as other blazars. PKS 2155-304 emitted a long-duration energetic flare in July 2006 with total isotropic equivalent energy released in TeV gamma rays of approximately 1045 ergs. Possible gravitational wave signals associated with this outburst are expected to be seen at the same time as the electromagnetic signal. During this flare, the two LIGO interferometers at Hanford and the GEO detector were in operation and collecting data. For this search we will use the data from multiple gravitational wave detectors. The method we use for this purpose is a coherent network analysis algorithm which is called RIDGE. To estimate the sensitivity of the search, we perform numerical simulations. For a detection probability of 20%, we estimate that this method is sensitive to total isotropic equivalent energy at the source of about 2.5 × 1055 ergs. For this analysis, an end-to-end pipeline has been developed, which takes into account the motion of the source across the sky.
117749606
Baryon content of massive galaxy clusters at 0.57 < z < 1.33
We study the stellar, brightest cluster galaxy (BCG) and intracluster medium (ICM) masses of 14 South Pole Telescope (SPT) selected galaxy clusters with median redshift z = 0.9 and mass M-500 = 6 x 10(14) M-circle dot. We estimate stellar masses for each cluster and BCG using six photometric bands, the ICM mass using X-ray observations and the virial masses using the SPT Sunyaev-Zel'dovich effect signature. At z = 0.9, the BCG mass M-*(BCG) constitutes 0.12 +/- 0.01 per cent of the halo mass for a 6 x 10(14) M-circle dot cluster, and this fraction falls as M-500(-0.58 +/- 0.07). The cluster stellar mass function has a characteristic mass M-0 = 10(11.0 +/- 0.1) M-circle dot, and the number of galaxies per unit mass in clusters is larger than in the field by a factor of 1.65 +/- 0.20. We combine our SPT sample with previously published samples at low redshift and correct to a common initial mass function and for systematic virial mass differences. We then explore mass and redshift trends in the stellar fraction f(*), the ICM fraction f(ICM), the collapsed baryon fraction f(c) and the baryon fraction f(b). At a pivot mass of 6 x 10(14) M-circle dot and redshift z = 0.9, the characteristic values are f(*) = 1.1 +/- 0.1 per cent, f(ICM) = 9.6 +/- 0.5 per cent, f(c) = 10.7 +/- 1.1 per cent and f(b) = 10.7 +/- 0.6 per cent. These fractions all vary with cluster mass at high significance, with higher mass clusters having lower f(*) and f(c) and higher f(ICM) and f(b). When accounting for a 15 per cent systematic virial mass uncertainty, there is no statistically significant redshift trend at fixed mass. Our results support the scenario where clusters grow through accretion from subclusters (higher f(*), lower f(ICM)) and the field (lower f(*), higher f(ICM)), balancing to keep f(*) and f(ICM) approximately constant since z similar to 0.9.
119180713
Searches for gravitational waves associated with pulsar glitches using a coherent network algorithm
Pulsar glitches are a potential source of gravitational waves for current and future interferometric gravitational wave detectors. Some pulsar glitch events were observed by radio and x-ray telescopes during the fifth LIGO science run. It is expected that glitches from these same pulsars should also be seen in the future. We carried out Monte Carlo simulations to estimate the sensitivity of possible gravitational wave signals associated with a pulsar glitch using a coherent network analysis method. We show the detection efficiency and evaluate the reconstruction accuracy of gravitational waveforms using a matched filter analysis on the estimated gravitational waveforms from the coherent analysis algorithm.
9665346
Measurement of galaxy cluster integrated comptonization and mass scaling relations with the South Pole Telescope
We describe a method for measuring the integrated Comptonization (Y_(SZ)) of clusters of galaxies from measurements of the Sunyaev-Zel'dovich (SZ) effect in multiple frequency bands and use this method to characterize a sample of galaxy clusters detected in the South Pole Telescope (SPT) data. We use a Markov Chain Monte Carlo method to fit a β-model source profile and integrate Y_(SZ) within an angular aperture on the sky. In simulated observations of an SPT-like survey that include cosmic microwave background anisotropy, point sources, and atmospheric and instrumental noise at typical SPT-SZ survey levels, we show that we can accurately recover β-model parameters for inputted clusters. We measure Y_(SZ) for simulated semi-analytic clusters and find that Y_(SZ) is most accurately determined in an angular aperture comparable to the SPT beam size. We demonstrate the utility of this method to measure Y_(SZ) and to constrain mass scaling relations using X-ray mass estimates for a sample of 18 galaxy clusters from the SPT-SZ survey. Measuring Y_(SZ) within a 0.'75 radius aperture, we find an intrinsic log-normal scatter of 21% ± 11% in Y_(SZ) at a fixed mass. Measuring Y_(SZ) within a 0.3 Mpc projected radius (equivalent to 0.'75 at the survey median redshift z = 0.6), we find a scatter of 26% ± 9%. Prior to this study, the SPT observable found to have the lowest scatter with mass was cluster detection significance. We demonstrate, from both simulations and SPT observed clusters that Y_(SZ) measured within an aperture comparable to the SPT beam size is equivalent, in terms of scatter with cluster mass, to SPT cluster detection significance.
9158947
The Dark Energy Survey Data Management System: The Processing Framework
The Dark Energy Survey Data Management (DESDM) system will process and archive the data from the Dark Energy Survey (DES) over the five year period of operation. This paper focuses on a new adaptable processing framework developed to perform highly automated, high performance data parallel processing. The new processing framework has been used to process 45 nights of simulated DECam supernova imaging data, and was extensively used in the DES Data Challenge 4, where it was used to process thousands of square degrees of simulated DES data.
125296528
Low-mass Higgs searches at the Tevatron
16162456
Production of a Higgs pseudoscalar plus two jets in hadronic collisions
We consider the production of a Higgs pseudoscalar accompanied by two jets in hadronic collisions. We work in the limit that the top quark is much heavier than the Higgs pseudoscalar and use an effective Lagrangian for the interactions of gluons with the pseudoscalar. We compute the amplitudes involving: 1) four gluons and the pseudoscalar, 2) two quarks, two gluons and the pseudoscalar and 3) four quarks and the pseudoscalar. We find that the pseudoscalar amplitudes are nearly identical to those for the scalar case, the only differences being the overall size and the relative signs between terms. We present numerical cross sections for proton-proton collisions with center-of-mass energy 14 TeV.
118867968
Production of a Higgs Boson Plus Two Jets in Hadronic Collisions
We consider the production of a Standard Model Higgs boson accompanied by two jets in hadronic collisions. We work in the limit that the top quark is much heavier than the Higgs boson and use an e ective Lagrangian for the interactions of gluons with the Higgs boson. In addition to the previously computed four-gluon process, we compute the the amplitudes involving two quarks, two gluons and the Higgs boson and those involving four quarks and the Higgs boson. We exhibit the form of our results in the small-pH and factorization limits. We present numerical results for p S = 14 TeV and p S = 2 TeV. We nd that the dominant processes are gg ! ggH and qg ! qgH with the former (latter) contributing about 60% (40%) of the cross section at p S = 14 TeV and the two processes each contributing about half the cross section at p S = 2 TeV. All other processes are negligible at both energies. September 1996
115397330
A Search for the Production of Technicolor Particles at the D-Zero Detector
A search for the Technicolor processes p{bar p} {yields} {rho}{sub T}{sup {+-}} {yields} W{sup {+-}}{pi}{sub T}{sup 0} {yields} {mu}{nu}b{bar b} and p{bar p} {yields} {rho}{sub T}{sup 0} {yields} W{sup {+-}}{pi}{sub T}{sup {+-}} {yields} {mu}{nu}b{bar c} is conducted at the D0 detector. Selection requirements are individually optimized for each of twenty mass hypotheses by means of a random grid search. No excess is seen in a 291 pb{sup -1} data set and 95% confidence level upper limits are set on the Technicolor production cross section. The mass combinations M{sub {rho}} = 195 GeV/c{sup 2}, M{sub {pi}} = 100 GeV/c{sup 2} and M{sub {rho}} = 200 GeV/c{sup 2}, M{sub {pi}} = 105 GeV/c{sup 2} are excluded for the choice of the Technicolor scale parameter M{sub V} = 500 GeV.
113469755
Radiation Damage Study of the D0 Silicon Microstrip Tracker
The Run II DØ experiment at the Fermilab Tevatron collider ha s been operating since 2001. At the heart of the DØ tracking system is a silicon microstrip de tector. It is built from four layers of single sided and double sided sensors organized in six bar rels, and two sets of seven disks. An additional, very small radius layer of silicon sensors, c onsisting of eight barrels, was inserted during the spring of 2006. We monitor the silicon sensors for radiation damage. A bulk c arrier-type reversal was observed in the innermost layer of the original detector after 1.5 fb −1 of integrated luminosity. We present the results of aging studies and predictions for lifetime of the detector for the rest of Run II at the Tevatron.