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Sample records for rapid cluster survey

  1. Household disaster preparedness and information sources: Rapid cluster survey after a storm in New South Wales, Australia

    PubMed Central

    Cretikos, Michelle; Eastwood, Keith; Dalton, Craig; Merritt, Tony; Tuyl, Frank; Winn, Linda; Durrheim, David

    2008-01-01

    Background A storm-related disaster in New South Wales, Australia in June 2007 caused infrastructure damage, interrupted essential services, and presented major public health risks. We investigated household disaster preparedness and information sources used before and during the disaster. Methods Rapid cluster survey of 320 randomly selected households in Newcastle and Lake Macquarie, New South Wales, Australia. Results 227 households (71%) responded to the survey. By the day before the storm, 48% (95%CI 40–57%) of households were aware of a storm warning, principally through television (67%; 58–75%) and radio (57%; 49–66%) announcements. Storm preparations were made by 42% (28–56%) of these households. Storm information sources included: radio (78%; 68–88%); family, friends, colleagues and neighbours (50%; 40–60%); and television (41%; 30–52%). Radio was considered more useful than television (62%; 51–73% vs. 29%; 18–40%), even in households where electricity supply was uninterrupted (52%; 31–73% vs. 41%; 20–63%). Only 23% (16–30%) of households were aware that the local government-operated radio network has a designated communication role during disasters. A battery-operated household radio and appropriate batteries were available in 42% (34–50%) of households, while only 23% (16–29%) had all of: a torch, battery-operated radio, appropriate batteries, mobile phone, emergency contact list and first aid equipment. Conclusion Broadcast media are important information sources immediately before and during disasters. Health services should promote awareness of broadcast networks' disaster role, especially the role of radio, and encourage general household disaster preparedness. A rapid cluster survey conducted shortly after a natural disaster provided practical, robust information for disaster planning. PMID:18533010

  2. Survey on granularity clustering.

    PubMed

    Ding, Shifei; Du, Mingjing; Zhu, Hong

    2015-12-01

    With the rapid development of uncertain artificial intelligent and the arrival of big data era, conventional clustering analysis and granular computing fail to satisfy the requirements of intelligent information processing in this new case. There is the essential relationship between granular computing and clustering analysis, so some researchers try to combine granular computing with clustering analysis. In the idea of granularity, the researchers expand the researches in clustering analysis and look for the best clustering results with the help of the basic theories and methods of granular computing. Granularity clustering method which is proposed and studied has attracted more and more attention. This paper firstly summarizes the background of granularity clustering and the intrinsic connection between granular computing and clustering analysis, and then mainly reviews the research status and various methods of granularity clustering. Finally, we analyze existing problem and propose further research. PMID:26557926

  3. HST Cluster Supernova Survey

    NASA Astrophysics Data System (ADS)

    Suzuki, Nao; Aldering, G.; Amanullah, R.; Barbary, K.; Barrientos, L.; Brodwin, M.; Connolly, N.; Dawson, K.; de Jong, R.; Dey, A.; Doi, M.; Donahue, M.; Eisenhardt, P.; Ellingson, E.; Faccioli, L.; Fadeyev, V.; Fakhouri, H.; Fruchter, A.; Gilbank, D.; Gladders, M.; Goldhaber, G.; Gonzalez, A.; Goobar, A.; Gude, A.; Hennawi, J.; Hoekstra, H.; Hsiao, E.; Huang, X.; Ihara, Y.; Jannuzi, B.; Jee, M. J.; Koester, B.; Kowalski, M.; Lidman, C.; Linder, E.; Lubin, L.; Morokuma, T.; Perlmutter, S.; Postman, M.; Rhodes, J.; Rosati, P.; Ripoche, P.; Rubin, D.; Schlegel, D.; Spadafora, A.; Stanford, A.; Stern, D.; Yasuda, N.; Yee, H.; Cosmology Project, Supernova

    2010-01-01

    We report results from the Hubble Space Telescope (HST) Cluster Supernova Survey with the Advanced Camera for Surveys (ACS) (PI: Perlmutter; see Dawson et al. AJ, 2009). We have introduced a novel approach to discover and follow Type Ia supernovae (SNeIa). With HST, we monitored 25 massive clusters (0.9 < z < 1.4) found by the RCS, XMM, IRAC, and RDCS surveys and conducted spectroscopic observations with the Keck, Subaru, and VLT telescopes. Sixteen SNe were discovered at 0.95 < z < 1.41, nine of which were in galaxy clusters (for a discussion of the rates, see K. Barbary, oral presentation at this meeting). The SNe in galaxy clusters are found primarily in early type galaxies in the cluster red-sequence that have been shown to be nearly dust-free and uniform populations (see poster presentation by Meyers et al.). The reduction and control of systematic error is an urgent task for the study of dark energy today (see Rubin et al. poster presentation), and we discuss how this unique SNe Ia data set reduces both statistical and more importantly systematic uncertainty at the highest redshifts. This work has been supported by the Office of Science, U.S. Department of Energy, through contract DE-AC02-05CH11231 and in part by NASA through grants associated with HST-GO-10496.

  4. Galaxy and cluster redshift surveys

    NASA Technical Reports Server (NTRS)

    Geller, Margaret J.; Huchra, John P.

    1988-01-01

    The present evaluation of galaxy and cluster redshift surveys gives attention to the CfA redshift survey and a deep Abell cluster redshift survey. These data support a structure in which galaxies lie on thin sheets which nearly surround vast, low-density voids. Voids such as that in Bootes are a common feature of galaxy distribution, posing a serious challenge for models. The Huchra et al. (1988) deep-cluster survey exhibits a correlation function amplitude that is a factor of about 2 smaller than that of the earlier Bahcall and Soneira (1983) sample; the difference may not be significant, however, because the cluster samples are sufficiently small to be dominated by single systems.

  5. SACS: Spitzer Archival Cluster Survey

    NASA Astrophysics Data System (ADS)

    Stern, Daniel

    Emerging from the cosmic web, galaxy clusters are the most massive gravitationally bound structures in the universe. Thought to have begun their assembly at z > 2, clusters provide insights into the growth of large-scale structure as well as the physics that drives galaxy evolution. Understanding how and when the most massive galaxies assemble their stellar mass, stop forming stars, and acquire their observed morphologies in these environments remain outstanding questions. The redshift range 1.3 < z < 2 is a key epoch in this respect: elliptical galaxies start to become the dominant population in cluster cores, and star formation in spiral galaxies is being quenched. Until recently, however, this redshift range was essentially unreachable with available instrumentation, with clusters at these redshifts exceedingly challenging to identify from either ground-based optical/nearinfrared imaging or from X-ray surveys. Mid-infrared (MIR) imaging with the IRAC camera on board of the Spitzer Space Telescope has changed the landscape. High-redshift clusters are easily identified in the MIR due to a combination of the unique colors of distant galaxies and a negative k-correction in the 3-5 μm range which makes such galaxies bright. Even 90-sec observations with Spitzer/IRAC, a depth which essentially all extragalactic observations in the archive achieve, is sufficient to robustly detect overdensities of L* galaxies out to z~2. Here we request funding to embark on a ambitious scientific program, the “SACS: Spitzer Archival Cluster Survey”, a comprehensive search for the most distant galaxy clusters in all Spitzer/IRAC extragalactic pointings available in the archive. With the SACS we aim to discover ~2000 of 1.3 < z < 2.5 clusters, thus provide the ultimate catalog for high-redshift MIR selected clusters: a lasting legacy for Spitzer. The study we propose will increase by more than a factor of 10 the number of high-redshift clusters discovered by all previous surveys

  6. The Swift AGN and Cluster Survey

    NASA Astrophysics Data System (ADS)

    Danae Griffin, Rhiannon; Dai, Xinyu; Kochanek, Christopher S.; Bregman, Joel N.; Nugent, Jenna

    2016-01-01

    The Swift active galactic nucleus (AGN) and Cluster Survey (SACS) uses 125 deg^2 of Swift X-ray Telescope serendipitous fields with variable depths surrounding X-ray bursts to provide a medium depth (4 × 10^-15 erg cm^-2 s^-1) and area survey filling the gap between deep, narrow Chandra/XMM-Newton surveys and wide, shallow ROSAT surveys. Here, we present the first two papers in a series of publications for SACS. In the first paper, we introduce our method and catalog of 22,563 point sources and 442 extended sources. We examine the number counts of the AGN and galaxy cluster populations. SACS provides excellent constraints on the AGN number counts at the bright end with negligible uncertainties due to cosmic variance, and these constraints are consistent with previous measurements. The depth and areal coverage of SACS is well suited for galaxy cluster surveys outside the local universe, reaching z ˜ 1 for massive clusters. In the second paper, we use Sloan Digital Sky Survey (SDSS) DR8 data to study the 203 extended SACS sources that are located within the SDSS footprint. We search for galaxy over-densities in 3-D space using SDSS galaxies and their photometric redshifts near the Swift galaxy cluster candidates. We find 103 Swift clusters with a > 3σ over-density. The remaining targets are potentially located at higher redshifts and require deeper optical follow-up observations for confirmations as galaxy clusters. We present a series of cluster properties including the redshift, BCG magnitude, BCG-to-X-ray center offset, optical richness, X-ray luminosity and red sequences. We compare the observed redshift distribution of the sample with a theoretical model, and find that our sample is complete for z ≤ 0.3 and 80% complete for z ≤ 0.4, consistent with the survey depth of SDSS. We also match our SDSS confirmed Swift clusters to existing cluster catalogs, and find 42, 2 and 1 matches in optical, X-ray and SZ catalogs, respectively, so the majority of these

  7. Time-Resolved Surveys of Stellar Clusters

    NASA Astrophysics Data System (ADS)

    Eyer, Laurent; Eggenberger, Patrick; Greco, Claudia; Saesen, Sophie; Anderson, Richard I.; Mowlavi, Nami

    We describe the information that can be gained when a survey is done multi-epoch, and its particular impact in open cluster research. We first explain the irreplaceable information that multi-epoch observations are giving within astrometry, photometry and spectroscopy. Then we give three examples of results on open clusters from multi-epoch surveys, namely, the distance to the Pleiades, the angular momentum evolution of low mass stars and asteroseismology. Finally we mention several very large surveys, which are ongoing or planned for the future, Gaia, JASMINE, LSST, and VVV.

  8. FUV imaging survey of Galactic open clusters

    NASA Astrophysics Data System (ADS)

    Maiz Apellaniz, Jesus

    2007-07-01

    We propose a WFPC2 FUV imaging survey of 6 Galactic open clusters with ages ranging from 1 Myr to 300 Myr complemented with NUV/optical imaging of the same fields. No such survey has ever been attempted before in the FUV at the resolution of WFPC2 {indeed, no WFPC2 FUV images of any Galactic open cluster exist in the HST archive} and, since WFPC2 will be retired in SM4 and none of the other HST instruments can do FUV imaging of bright objects, this is the last chance to do such a survey before another UV telescope is launched. This survey will provide a new perspective on young/intermediate age Galactic clusters and a key template for the study of star formation at high redshift, where the intensity peak we observe in the optical/NIR from Earth is located in the FUV in its rest frame. For clusters still associated with an H II region, UV imaging maps the continuum emission of the ionized gas and the radiation scattered by background dust and, combined with optical nebular images, can be used to determine the 3-D structure of the H II region. For all young clusters, FUV+NUV+optical photometry can be used to study the UV excesses of T-Tauri stars. For clusters older than 40 Myr, the same photometric combination is the easiest method to detect companion white dwarfs which are invisible using only the optical and NIR. WFPC2 is also an excellent instrument to discover close companions around bright stars and improve our knowledge of their multiplicity fraction. Finally, for all clusters, the combination of high-spatial-resolution UV and optical photometry can be used to simultaneously measure the temperature, extinction, extinction law, distance, and existence of companions {resolved and unresolved} and, thus, produce clean HR diagrams with resolved cluster membership and much-reduced systematic uncertainties.

  9. Extreme Mergers from the Massive Cluster Survey

    NASA Astrophysics Data System (ADS)

    Morris, Roger

    2010-09-01

    We propose to observe two extraordinary, high-redshift galaxy clusters from the Massive Cluster Survey. Both targets are very rare, triple merger systems (one a nearly co-linear merger), and likely lie at the deepest nodes of the cosmic web. Both targets show multiple strong gravitational lensing arcs in the cluster cores. These targets only possess very short (10ks) Chandra observations, and are unobserved by XMM-Newton. The X-ray data will be used to probe the mass distribution of hot, baryonic gas, and to reveal the details of the merger physics and the process of cluster assembly. We will also search for hints of X-ray emission from filaments between the merging clumps. Subaru and Hubble Space Telescope imaging data are in hand; we request additional HST coverage for one object.

  10. Extreme Mergers from the Massive Cluster Survey

    NASA Astrophysics Data System (ADS)

    Morris, R.

    2010-09-01

    We will observe an extraordinary, high-redshift galaxy cluster from the Massive Cluster Survey. The target is a very rare, triple merger system, and likely lies at the one of deepest nodes of the cosmic web. The target shows multiple strong gravitational lensing arcs in the cluster core. This target only possesses a very short {10ks} Chandra observations, and is unobserved by XMM-Newton. The X-ray data from this joint Chandra/HST proposal will be used to probe the mass distribution of hot, baryonic gas, and to reveal the details of the merger physics and the process of cluster assembly. We will also search for hints of X-ray emission from filaments between the merging clumps. Subaru and some Hubble Space Telescope imaging data are in hand; we will gather additional HST coverage for a lensing analysis.

  11. ChaMP Serendipitous Galaxy Cluster Survey

    SciTech Connect

    Barkhouse, Wayne A.; Green, P.J.; Vikhlinin, A.; Kim, D.-W.; Perley, D.; Cameron, R.; Silverman, J.; Mossman, A.; Burenin, R.; Jannuzi, B.T.; Kim, M.; Smith, M.G.; Smith, R.C.; Tananbaum, H.; Wilkes, B.J.; /Harvard-Smithsonian Ctr. Astrophys. /UC, Berkeley, Astron. Dept. /SLAC /Garching, Max Planck Inst., MPE /Moscow, Space Res. Inst. /NOAO, Tucson /Cerro-Tololo InterAmerican Obs.

    2006-04-03

    We present a survey of serendipitous extended X-ray sources and optical cluster candidates from the Chandra Multi-wavelength Project (ChaMP). Our main goal is to make an unbiased comparison of X-ray and optical cluster detection methods. In 130 archival Chandra pointings covering 13 square degrees, we use a wavelet decomposition technique to detect 55 extended sources, of which 6 are nearby single galaxies. Our X-ray cluster catalog reaches a typical flux limit of about {approx} 10{sup -14} erg s{sup -1} cm{sup -2}, with a median cluster core radius of 21''. For 56 of the 130 X-ray fields, we use the ChaMP's deep NOAO/4m MOSAIC g', r', and i' imaging to independently detect cluster candidates using a Voronoi tessellation and percolation (VTP) method. Red-sequence filtering decreases the galaxy fore/background contamination and provides photometric redshifts to z {approx} 0.7. From the overlapping 6.1 square degree X-ray/optical imaging, we find 115 optical clusters (of which 11% are in the X-ray catalog) and 28 X-ray clusters (of which 46% are in the optical VTP catalog). The median redshift of the 13 X-ray/optical clusters is 0.41, and their median X-ray luminosity (0.5-2 keV) is L{sub X} = (2.65 {+-} 0.19) x 10{sup 43} ergs s{sup -1}. The clusters in our sample that are only detected in our optical data are poorer on average ({approx} 4{sigma}) than the X-ray/optically matched clusters, which may partially explain the difference in the detection fractions.

  12. The Rapid Geodetic Survey System (RGSS)

    NASA Technical Reports Server (NTRS)

    Huddle, J. R.

    1989-01-01

    The Rapid Geodetic Survey System (RGSS) is a system employing a high-accuracy gimbaled inertial platform. It provides a cost-effective capability for accurate direct measurement of the change in position, elevation, gravity intensity and deflection of the vertical from an initial point. The RGSS is an adaptation of the production version of the U.S. Army Position and Azimuth Determining System (PADS). Several hardware and software enhancements to improve the performance of the system, primarily for gravity vector survey, have occurred over the last few years. The basic principles for the control of error in the survey measurements due to noise and systematic error are discussed below. Actual acceptance test results for the RGSS which indicate an inherent capability of the system to measure change in the deflection of the vertical to a few-tenths of an arcsecond over survey periods of one to two hours using careful survey techniques are also presented. Finally a simple method to extend the capability of the system for longer duration surveys is indicated.

  13. The Rapid Geodetic Survey System (RGSS)

    NASA Astrophysics Data System (ADS)

    Huddle, J. R.

    1989-06-01

    The Rapid Geodetic Survey System (RGSS) is a system employing a high-accuracy gimbaled inertial platform. It provides a cost-effective capability for accurate direct measurement of the change in position, elevation, gravity intensity and deflection of the vertical from an initial point. The RGSS is an adaptation of the production version of the U.S. Army Position and Azimuth Determining System (PADS). Several hardware and software enhancements to improve the performance of the system, primarily for gravity vector survey, have occurred over the last few years. The basic principles for the control of error in the survey measurements due to noise and systematic error are discussed below. Actual acceptance test results for the RGSS which indicate an inherent capability of the system to measure change in the deflection of the vertical to a few-tenths of an arcsecond over survey periods of one to two hours using careful survey techniques are also presented. Finally a simple method to extend the capability of the system for longer duration surveys is indicated.

  14. The SDSS-ROSAT Cluster Survey

    NASA Astrophysics Data System (ADS)

    Nichol, R.; Computational AstroStatistics Team; SDSS Collaboration

    2000-10-01

    Clusters of galaxies are key tracers of the mass in the universe. Therefore, by studying their distribution and evolution, we can obtain strong constraints on the underlying cosmological model. This is especially true once cluster observations are combined with CMB and Supernovae data to form the ``Cosmic Triangle'' (Bahcall et al. 2000). To obtain high precision cluster observations, we need new, larger, catalogs of clusters that span a wide dynamic range in both redshift and mass as well as possessing a well-understood selection function. In this talk, I will outline the construction of such a catalog through the combination of the Sloan Digital Sky Survey and the ROSAT data (both archival pointings and the all-sky survey). This catalog is predicted to contain of the order of 10,000 clusters/groups out to z~=0.7 and thus provide a tight constraint on Ω m, the mass density of the universe (Δ Ω m < 10% at the 3σ level). To facilitate in the construction of this new catalog, we are employing new efficient statistics developed as part of a new collaboration - called ``Computational AstroStatistics'' - between Astrophysicists, Computer Scientists and Statisticians. I will review these new methodologies which include the use of the EM algorthm in classifying X-ray sources, the use of Mixture Models to simultaneously cluster X-ray and optical data and the use of multi-resolutional KD-trees for fast correlations between catalogues. This research is partially funded via an NSF KDI grant.

  15. Clusters of Galaxies in the Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Jeltema, Tesla E.; DES Collaboration

    2016-01-01

    The growth rate of clusters of galaxies is highly sensitive to the underlying cosmology. In fact, clusters will provide one of the most precise methods of constraining dark energy with large-area optical surveys like the Dark Energy Survey (DES). However, extracting precision cosmology from cluster surveys necessarily depends on having a well-understood method of selecting clusters and accurately translating their observed properties to underlying mass. I will discuss the status of the DES cluster survey as well as efforts to calibrate the cluster richness-mass relation.

  16. Galaxy Clustering in the Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Ross, Ashley; Dark Energy Survey Large-Scale Structure Working Group

    2016-01-01

    I will present the status of galaxy clustering results in the Dark Energy Survey (DES).DES will image the sky over 5000 deg2 in five photometric bands (grizY) to a nominal depth (iAB ~ 24), enabling the structure of the Universe to be studied to redshift 1.2 and beyond. I will present results of the clustering analyses performed to date, including those from Crocce et al. (2015), who studied the clustering of DES data over five tomographic bins, with photometric redshifts, z, in the range 0.2 < z < 1.2, and those from the `redMaGiC' sample (Rozo et al. 2015), which provides accurate (better than 2%) photometric redshifts for luminous red galaxies. I will describe how these measurements can be combined with weak lensing analyses to probe the growth of structure. Finally, I will report on how DES data can provide a 2% measurement of the angular diameter distance to z~0.9 by measuring the position of baryon acoustic oscillation feature in the clustering of DES galaxies.

  17. Rapid Self-Assembly of Uranyl Polyhedra into Crown Clusters

    SciTech Connect

    Sigmon, Ginger E.; Burns, Peter C.

    2011-06-22

    Clusters built from 32 uranyl peroxide polyhedra self-assemble and crystallize within 15 min after combining uranyl nitrate, ammonium hydroxide, and hydrogen peroxide in aqueous solution under ambient conditions. These novel crown-shaped clusters are remarkable in that they form so quickly, have extraordinarily low aqueous solubility, form with at least two distinct peroxide to hydroxyl ratios, and form in very high yield. The clusters, which have outer diameters of 23 Å, topologically consist of eight pentagons and four hexagons. Their rapid formation and low solubility in aqueous systems may be useful properties at various stages in an advanced nuclear energy system.

  18. The BMW Deep X-Ray Cluster Survey

    NASA Astrophysics Data System (ADS)

    Guzzo, Luigi; Moretti, Alberto; Campana, Sergio; Covino, Stefano; Dell'Antonio, Ian; Lazzati, Davide; Longhetti, Marcella; Molinari, Emilio; Panzera, Maria Rosa; Tagliaferri, Gianpiero

    We briely describe the main features and first results of the BMW survey of serendipitous X-ray clusters, based on the still unexploited ROSAT-HRI archival observations. The sky coverage, surface density and first deep CCD images of the candidates indicate that this sample can represent an excellent complement to the existing PSPC deep cluster surveys.

  19. Distant Compact Clusters of Galaxies from the BMW survey

    NASA Astrophysics Data System (ADS)

    Dell'Antonio, Ian; Guzzo, Luigi; Longhetti, Marcella; Moretti, Alberto; Campana, Sergio; Lazzati, Davide; Panzera, Mariarosa; Tagliaferri, Gianpiero

    2002-02-01

    We propose to use SQIID to identify high-redshift clusters of galaxies from the BMW, an X-ray selected sample of serendipitously detected extended sources from the ROSAT HRI archive. The BMW survey is unique because of the superior angular resolution of the HRI. In fact, this is the only modern sample of distant clusters available that is not based on the low-resolution PSPC. Using 4m optical imaging, we have already identified several high-redshift clusters, two of which have z> 0.8, thus confirming the ability of the survey to peer efficiently into the z~ 1 regime, where only a handful of X-ray clusters are known. To test the evolution of the cluster abundance, we must increase the number of clusters known in this redshift regime. The BMW survey provides us with the only current opportunity to study compact clusters missing in all PSPC surveys. Because z~ 1 ellipticals have very red colors, K-band imaging is the most effective way of identifying these clusters. With SQIID, we also can obtain redshift estimates via the J-K red sequence. We propose near-IR imaging in J,H,K of 30 highest-z cluster candidates from the BMW survey, as indicated by their small size and low flux. This will allow efficient use of 8-meter spectroscopy to follow up the high-end tail of the redshift distribution.

  20. Hierarchical modeling of cluster size in wildlife surveys

    USGS Publications Warehouse

    Royle, J. Andrew

    2008-01-01

    Clusters or groups of individuals are the fundamental unit of observation in many wildlife sampling problems, including aerial surveys of waterfowl, marine mammals, and ungulates. Explicit accounting of cluster size in models for estimating abundance is necessary because detection of individuals within clusters is not independent and detectability of clusters is likely to increase with cluster size. This induces a cluster size bias in which the average cluster size in the sample is larger than in the population at large. Thus, failure to account for the relationship between delectability and cluster size will tend to yield a positive bias in estimates of abundance or density. I describe a hierarchical modeling framework for accounting for cluster-size bias in animal sampling. The hierarchical model consists of models for the observation process conditional on the cluster size distribution and the cluster size distribution conditional on the total number of clusters. Optionally, a spatial model can be specified that describes variation in the total number of clusters per sample unit. Parameter estimation, model selection, and criticism may be carried out using conventional likelihood-based methods. An extension of the model is described for the situation where measurable covariates at the level of the sample unit are available. Several candidate models within the proposed class are evaluated for aerial survey data on mallard ducks (Anas platyrhynchos).

  1. Radio Sources In Galaxy Clusters Using The Maxbcg Cluster Catalog, First And NVSS Surveys

    NASA Astrophysics Data System (ADS)

    Wu, Wai Ling; McKay, T. A.

    2008-05-01

    Using the maxBCG cluster catalog derived from the Sloan Digital Sky Survey, the FIRST, and the NVSS radio surveys, we studied the fraction of brightest central galaxies (BCG) in clusters that host a radio source, how much more likely is a radio source to live in a cluster environment compare to the field, and we differentiate the luminosity effect from the richness effect on the radio fraction using a sample of luminous red galaxies (LRG). We present a method to cross-correlate the optical survey and the radio surveys. We also apply the matching of radio sources to clusters to help better determine cluster centers in some pathological cases in the maxBCG cluster catalog.

  2. Cluster analysis of the hot subdwarfs in the PG survey

    NASA Technical Reports Server (NTRS)

    Thejll, Peter; Charache, Darryl; Shipman, Harry L.

    1989-01-01

    Application of cluster analysis to the hot subdwarfs in the Palomar Green (PG) survey of faint blue high-Galactic-latitude objects is assessed, with emphasis on data noise and the number of clusters to subdivide the data into. The data used in the study are presented, and cluster analysis, using the CLUSTAN program, is applied to it. Distances are calculated using the Euclidean formula, and clustering is done by Ward's method. The results are discussed, and five groups representing natural divisions of the subdwarfs in the PG survey are presented.

  3. The BMW Deep X-ray Cluster Survey

    NASA Astrophysics Data System (ADS)

    Moretti, A.; Guzzo, L.; Campana, S.; Covino, S.; Lazzati, D.; Longhetti, M.; Molinari, E.; Panzera, M. R.; Tagliaferri, G.; dell'Antonio, I.

    We describe the main features of the BMW survey of serendipitous X-ray clusters, based on the still unexploited ROSAT-HRI archival observations. The sky coverage, surface density and first deep optical CCD images of the candidates indicate that this sample can represent an excellent complement to the existing PSPC deep cluster surveys and will provide us with a fully independent probe of the evolution of the cluster abundance, in addition to significantly increasing the number of clusters known at z>0.6.

  4. LENSING NOISE IN MILLIMETER-WAVE GALAXY CLUSTER SURVEYS

    SciTech Connect

    Hezaveh, Yashar; Vanderlinde, Keith; Holder, Gilbert; De Haan, Tijmen

    2013-08-01

    We study the effects of gravitational lensing by galaxy clusters of the background of dusty star-forming galaxies (DSFGs) and the cosmic microwave background (CMB), and examine the implications for Sunyaev-Zel'dovich-based (SZ) galaxy cluster surveys. At the locations of galaxy clusters, gravitational lensing modifies the probability distribution of the background flux of the DSFGs as well as the CMB. We find that, in the case of a single-frequency 150 GHz survey, lensing of DSFGs leads both to a slight increase ({approx}10%) in detected cluster number counts (due to a {approx}50% increase in the variance of the DSFG background, and hence an increased Eddington bias) and a rare (occurring in {approx}2% of clusters) 'filling-in' of SZ cluster signals by bright strongly lensed background sources. Lensing of the CMB leads to a {approx}55% reduction in CMB power at the location of massive galaxy clusters in a spatially matched single-frequency filter, leading to a net decrease in detected cluster number counts. We find that the increase in DSFG power and decrease in CMB power due to lensing at cluster locations largely cancel, such that the net effect on cluster number counts for current SZ surveys is subdominant to Poisson errors.

  5. Psychometric Properties of the Career Clusters Interest Survey

    ERIC Educational Resources Information Center

    Prime, Dominic R.; Tracey, Terence J. G.

    2010-01-01

    The current study examined the psychometric support of the Career Clusters Interest Survey (CCIS) that provides subscales scores for the 16 Office of Vocational and Adult Education (OVAE) career clusters in a sample of 203 college students. Reliability of the subscales was supported with respect to internal consistency and 2-week stability…

  6. A Survey on Clustering Routing Protocols in Wireless Sensor Networks

    PubMed Central

    Liu, Xuxun

    2012-01-01

    The past few years have witnessed increased interest in the potential use of wireless sensor networks (WSNs) in a wide range of applications and it has become a hot research area. Based on network structure, routing protocols in WSNs can be divided into two categories: flat routing and hierarchical or clustering routing. Owing to a variety of advantages, clustering is becoming an active branch of routing technology in WSNs. In this paper, we present a comprehensive and fine grained survey on clustering routing protocols proposed in the literature for WSNs. We outline the advantages and objectives of clustering for WSNs, and develop a novel taxonomy of WSN clustering routing methods based on complete and detailed clustering attributes. In particular, we systematically analyze a few prominent WSN clustering routing protocols and compare these different approaches according to our taxonomy and several significant metrics. Finally, we summarize and conclude the paper with some future directions. PMID:23112649

  7. Next-generation X-ray cluster surveys

    NASA Astrophysics Data System (ADS)

    Slack, N. W.; Ponman, T. J.

    2014-03-01

    Contemporary X-ray surveys have permitted rich galaxy clusters to be detected out to redshifts z > 1, but studies with next-generation instruments will allow this work to be extended to both higher redshift and lower cluster masses. Such studies have the potential to provide powerful constraints on the evolution of baryonic processes such as cooling and feedback within developing cosmic structures, provided that observational selection effects can be controlled. To explore this, we generate simulated surveys using the Wide Field Imager (WFI) instrument on International X-ray Observatory (IXO), studied in 2010 by NASA and ESA as a major next-generation X-ray observatory. A sample of observed groups and clusters is assembled and used to derive relationships between temperature and four cluster properties: M500, L500, core radius and β. These are coupled with an evolving population of dark matter haloes drawn from the Millennium Simulation to construct an evolving set of X-ray clusters which are cast into a lightcone and imaged using the main instrumental characteristics of the IXO WFI. State-of-the-art techniques are then employed for source detection and extension testing, to generate a simulated survey cluster catalogue. These simulations are used to explore the dependence of a next-generation survey on the evolution of cluster scaling relations, survey strategy (wide versus deep) and instrument point spread function (PSF). We find that a 1.8 Ms IXO survey gives a cluster sample three to five times larger for a wide survey compared to a deep survey. In both surveys, the strongest discrimination between different LX-T evolutionary models derives from galaxy groups, with T ˜ 1-2 keV. Deep surveys can be affected by cosmic variance within this temperature range, whilst wide surveys suffer from incompleteness, and hence are more vulnerable to biases arising from incomplete knowledge of the survey selection function. Degrading the telescope PSF is found to most

  8. Rapid Acoustic Survey for Biodiversity Appraisal

    PubMed Central

    Sueur, Jérôme; Pavoine, Sandrine; Hamerlynck, Olivier; Duvail, Stéphanie

    2008-01-01

    Biodiversity assessment remains one of the most difficult challenges encountered by ecologists and conservation biologists. This task is becoming even more urgent with the current increase of habitat loss. Many methods–from rapid biodiversity assessments (RBA) to all-taxa biodiversity inventories (ATBI)–have been developed for decades to estimate local species richness. However, these methods are costly and invasive. Several animals–birds, mammals, amphibians, fishes and arthropods–produce sounds when moving, communicating or sensing their environment. Here we propose a new concept and method to describe biodiversity. We suggest to forego species or morphospecies identification used by ATBI and RBA respectively but rather to tackle the problem at another evolutionary unit, the community level. We also propose that a part of diversity can be estimated and compared through a rapid acoustic analysis of the sound produced by animal communities. We produced α and β diversity indexes that we first tested with 540 simulated acoustic communities. The α index, which measures acoustic entropy, shows a logarithmic correlation with the number of species within the acoustic community. The β index, which estimates both temporal and spectral dissimilarities, is linearly linked to the number of unshared species between acoustic communities. We then applied both indexes to two closely spaced Tanzanian dry lowland coastal forests. Indexes reveal for this small sample a lower acoustic diversity for the most disturbed forest and acoustic dissimilarities between the two forests suggest that degradation could have significantly decreased and modified community composition. Our results demonstrate for the first time that an indicator of biological diversity can be reliably obtained in a non-invasive way and with a limited sampling effort. This new approach may facilitate the appraisal of animal diversity at large spatial and temporal scales. PMID:19115006

  9. A NEW DISTANT MILKY WAY GLOBULAR CLUSTER IN THE PAN-STARRS1 3π SURVEY

    SciTech Connect

    Laevens, Benjamin P. M.; Martin, Nicolas F.; Sesar, Branimir; Rix, Hans-Walter; Schlafly, Edward F.; Bernard, Edouard J.; Ferguson, Annette M. N.; Slater, Colin T.; Bell, Eric F.; Burgett, William S.; Chambers, Kenneth C.; Denneau, Larry; Kaiser, Nicholas; Kudritzki, Rolf-Peter; Magnier, Eugene A.; Morgan, Jeffrey S.; Sweeney, William E.; Draper, Peter W.; Metcalfe, Nigel; Price, Paul A.; and others

    2014-05-01

    We present a new satellite in the outer halo of the Galaxy, the first Milky Way satellite found in the stacked photometric catalog of the Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1) Survey. From follow-up photometry obtained with WFI on the MPG/ESO 2.2 m telescope, we argue that the object, located at a heliocentric distance of 145 ± 17 kpc, is the most distant Milky Way globular cluster yet known. With a total magnitude of M{sub V} = –4.3 ± 0.2 and a half-light radius of 20 ± 2 pc, it shares the properties of extended globular clusters found in the outer halo of our Galaxy and the Andromeda galaxy. The discovery of this distant cluster shows that the full spatial extent of the Milky Way globular cluster system has not yet been fully explored.

  10. Rapid topography mapping of scalar fields: Large molecular clusters

    NASA Astrophysics Data System (ADS)

    Yeole, Sachin D.; López, Rafael; Gadre, Shridhar R.

    2012-08-01

    An efficient and rapid algorithm for topography mapping of scalar fields, molecular electron density (MED) and molecular electrostatic potential (MESP) is presented. The highlight of the work is the use of fast function evaluation by Deformed-atoms-in-molecules (DAM) method. The DAM method provides very rapid as well as sufficiently accurate function and gradient evaluation. For mapping the topography of large systems, the molecular tailoring approach (MTA) is invoked. This new code is tested out for mapping the MED and MESP critical points (CP's) of small systems. It is further applied to large molecular clusters viz. (H2O)25, (C6H6)8 and also to a unit cell of valine crystal at MP2/6-31+G(d) level of theory. The completeness of the topography is checked by extensive search as well as applying the Poincaré-Hopf relation. The results obtained show that the DAM method in combination with MTA provides a rapid and efficient route for mapping the topography of large molecular systems.

  11. Early Results from Swift AGN and Cluster Survey

    NASA Astrophysics Data System (ADS)

    Dai, Xinyu; Griffin, Rhiannon; Nugent, Jenna; Kochanek, Christopher S.; Bregman, Joel N.

    2016-04-01

    The Swift AGN and Cluster Survey (SACS) uses 125 deg^2 of Swift X-ray Telescope serendipitous fields with variable depths surrounding gamma-ray bursts to provide a medium depth (4 × 10^-15 erg cm^-2 s^-1) and area survey filling the gap between deep, narrow Chandra/XMM-Newton surveys and wide, shallow ROSAT surveys. Here, we present the first two papers in a series of publications for SACS. In the first paper, we introduce our method and catalog of 22,563 point sources and 442 extended sources. SACS provides excellent constraints on the AGN and cluster number counts at the bright end with negligible uncertainties due to cosmic variance, and these constraints are consistent with previous measurements. The depth and areal coverage of SACS is well suited for galaxy cluster surveys outside the local universe, reaching z > 1 for massive clusters. In the second paper, we use SDSS DR8 data to study the 203 extended SACS sources that are located within the SDSS footprint. We search for galaxy over-densities in 3-D space using SDSS galaxies and their photometric redshifts near the Swift galaxy cluster candidates. We find 103 Swift clusters with a > 3σ over-density. The remaining targets are potentially located at higher redshifts and require deeper optical follow-up observations for confirmations as galaxy clusters. We present a series of cluster properties including the redshift, BCG magnitude, BCG-to-X-ray center offset, optical richness, X-ray luminosity and red sequences. We compare the observed redshift distribution of the sample with a theoretical model, and find that our sample is complete for z ≤ 0.3 and 80% complete for z ≤ 0.4, consistent with the survey depth of SDSS. These analysis results suggest that our Swift cluster selection algorithm presented in our first paper has yielded a statistically well-defined cluster sample for further studying cluster evolution and cosmology. In the end, we will discuss our ongoing optical identification of z>0.5 cluster

  12. High-Redshift Clusters form NVSS: The TexOx Cluster (TOC) Survey

    SciTech Connect

    Croft, S; Rawlings, S; Hill, G J

    2003-02-11

    The TexOx Cluster (TOC) Survey uses overdensities of radiosources in the NVSS to trace clusters of galaxies. The links between radiosources and rich environments make this a powerful way to find clusters which may potentially be overlooked by other selection techniques. By including constraints from optical surveys, TOC is an extremely efficient way to find clusters at high redshift. One such field, TOC J0233.3+3021, contains at least one galaxy cluster (at z {approx} 1.4) and has been detected using the Sunyaev-Zel'dovich (SZ) effect. Even in targeted deep optical observations, however, distinguishing the cluster galaxies from the background is difficult, especially given the tendency of TOC to select fields containing multiple structures at different redshifts.

  13. A Survey For Embedded Clusters in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Romita, Krista; Lada, Elizabeth A.; Cioni, Maria-Rosa

    2016-01-01

    In the Milky Way, the majority of stars form in embedded clusters (Lada & Lada 2003), which makes them a fundamental unit of star formation. Despite their importance, our knowledge of cluster formation remains primitive. For example, we don't have a clear idea of how varying physical environments affects the cluster formation process. In order to address this, we have begun a comprehensive, systematic search for embedded stellar clusters in the Large Magellanic Cloud (LMC) using near-infrared data from the VISTA Magellanic Clouds Survey (Cioni et al. 2011). To date, we have searched 46% of the molecular clouds in the MAGMA CO Survey (Wong et al. 2011). We have identified 125 embedded cluster candidates. This is approximately double the number of embedded clusters that have been identified within ~2.5 kpc of the Sun (Lada & Lada 2003). We have determined sizes, luminosities, and masses for these embedded clusters and calculated the star formation rates (SFRs) of the LMC molecular clouds containing clusters, and finally compared the LMC and Milky Way embedded cluster properties and SFRs. Our preliminary results indicate the LMC embedded clusters are larger, more luminous and more massive than the embedded clusters in the local Milky Way. However, even though the overall cluster properties differ in these two environments, the SFRs of the molecular clouds in both environments are consistent with the SFR scaling law from Lada et al. (2012). This consistency may indicate that while the details of embedded cluster formation may vary between environments, the overall star formation process within molecular clouds may be universal.

  14. Galaxy Clusters and Properties in the CFHTLS/VIPERS Survey

    NASA Astrophysics Data System (ADS)

    Gallego Gallego, Sofia Carolina; Murphy, David; Hyazinth Puzia, Thomas

    2015-08-01

    We present our analysis of clusters in the CFHTLS Wide fields using a red-sequence based cluster finding code. The deep five-band photometry and panoramic coverage permits detection of galaxy clusters between z=0 and z~1 over 132 square degrees. We present a cluster catalogue and optical richness estimates as mass proxies, derived cluster properties from a novel template-fitting analysis and cluster redshift measurements utilizing data from the VLT/VIPERS spectroscopic survey.We complement our analysis with studies of mock cluster catalogues generated from N-body simulation lightcones featuring semi-analytic prescriptions of galaxy formation. These provide us with an insight into the performance of the cluster-finding technique, uncertainties in the derived properties of the detected cluster populations and an important comparison of the popular “lambda” optical richness estimator to known dark matter halo properties.This study serves as the perfect precursor to LSST-depth cluster science, providing an important input into how models describe the evolution of clusters and their members as a function of redshift and mass, and the role high-density environments play in galaxy evolution over half the Hubble time.

  15. RAPID: The imaging energetic particle spectrometer on Cluster

    NASA Technical Reports Server (NTRS)

    Wilken, B.; Guettler, W.; Korth, A.; Livi, S.; Weiss, W.; Gliem, F.; Muellers, A.; Rathje, R.; Fritz, T. A.; Fennell, J. F.

    1993-01-01

    The RAPID spectrometer for the Cluster mission, an advanced particle detector for the analysis of suprathermal plasma distributions in the energy range from 20 to 400 keV and from 2 keV/nuc to 1500 keV for electrons and ions, respectively, is presented. Novel detector concepts in combination with pinhole acceptance permit the measurement of angular distributions over a range of 180 deg in polar angle for either species. The detection principle for the ionic component is based on a two dimensional analysis of a particle's velocity and energy. Electrons are identified by the well known energy range relationship. The detection techniques are described and selected areas in geospace are used to highlight the scientific objectives of this investigation.

  16. Massive open star clusters using the VVV survey. V. Young clusters with an OB stellar population

    NASA Astrophysics Data System (ADS)

    Ramírez Alegría, S.; Borissova, J.; Chené, A.-N.; Bonatto, C.; Kurtev, R.; Amigo, P.; Kuhn, M.; Gromadzki, M.; Carballo-Bello, J. A.

    2016-04-01

    Context. The ESO public survey VISTA Variables in the Vía Láctea (VVV) has contributed with deep multi-epoch photometry of the Galactic bulge and the adjacent part of the disk over 526 sq. deg. More than a hundred cluster candidates have been reported thanks to this survey. Aims: We present the fifth article in a series of papers focused on young and massive clusters discovered in the VVV survey. In this paper, we present the physical characterization of five clusters with a spectroscopically confirmed OB-type stellar population. Methods: To characterize the clusters, we used near-infrared photometry (J, H, and KS) from the VVV survey and near-infrared K-band spectroscopy from ISAAC at VLT, following the methodology presented in the previous articles of the series. Results: All clusters in our sample are very young (ages between 1-20 Myr), and their total mass are between (1.07+0.40-0.30)×102 M⊙ and (4.17+4.15-2.08)×103 M⊙. We observed a relation between the clusters total mass Mecl and the mass of their most massive stellar member mmax, for clusters with an age <10 Myr. Based on observations taken within the ESO VISTA Public Survey VVV (programme ID 179.B-2002), and with ISAAC/VLT (programme 087.D-0341(A)).

  17. Giant Rapid X-ray Flares in Extragalactic Globular Clusters

    NASA Astrophysics Data System (ADS)

    Irwin, Jimmy; Maksym, W. Peter; Romanowsky, Aaron J.; Strader, Jay; Lin, Dacheng

    2016-01-01

    There is only one known class of non-destructive, highly energetic astrophysical object in the Universe whose energy emission varies by more than a factor of 100 on time scales of less than a minute -- soft gamma repeaters/anomalous X-ray pulsars, whose flares are believed to be caused by the energy release from the cracking of a neutron star's surface by very strong magnetic fields. All other known violent, rapid explosions, including gamma-ray bursts and supernovae, are believed to destroy the object in the process. Here, we report the discovery of a second class of non-destructive, highly energetic rapidly flaring X-ray object located within two nearby galaxies with fundamentally different properties than soft gamma repeaters/anomalous X-ray pulsars. One source is located within a suspected globular cluster of the host galaxy and flared one time, while the other source is located in either a globular cluster of the host galaxy or the core of a stripped dwarf companion galaxy that flared on five occasions over a seven year time span. When not flaring, the sources appear as normal accreting neutron star or black hole X-ray binaries, indicating that the flare event does not significantly disrupt the host system. While the nature of these sources is still unclear, the discovery of these sources in decade-old archival Chandra X-ray Observatory data illustrates the under-utilization of X-ray timing as a means to discover new classes of explosive events in the Universe.

  18. Spectroscopic and Photometric Surveys of the Milky Way and its Stellar Clusters in the Gaia Era

    NASA Astrophysics Data System (ADS)

    Feltzing, S.

    This contribution to the Stellar Clusters & Associations: A RIA Workshop on Gaia deals with surveys of stars, in particular spectroscopic surveys, with attention to their impact on cluster studies, and their connection with Gaia. I review some of the scientific reasons why we want large spectroscopic surveys, and what requirements these put on the instrumentation. Then I turn to a review of the current and future instrumentation that will enable us to complement Gaia's excellent distances and proper motions with the desired ground-based spectroscopy to obtain additional radial velocities and elemental abundances of high quality. This is a very fast moving area with several new surveys using existing and future multi-object spectrographs on 4- and 8-meter telescopes. As things change rapidly it is difficult to give adequate information on all these projects, but with the inclusion of links to the relevant websites the reader should be able to follow the latest developments as they unfold.

  19. The XMM Cluster Survey: Present status and latest results

    NASA Astrophysics Data System (ADS)

    Viana, P. T. P.; Mehrtens, N.; Harrison, C. D.; Romer, A. K.; Collins, C. A.; Hilton, M.; Hoyle, B.; Kay, S. T.; Liddle, A. R.; Mayers, J. A.; Miller, C. J.; Rooney, P. J.; Sahlén, M.; Stott, J. P.

    2013-04-01

    The XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters using all publicly available data in the XMM-Newton Science Archive. Our recent first data release (XCS-DR1) contains 503 optically confirmed groups and clusters, among which 256 new to the literature and 357 whose X-ray emission was detected for the first time. We discuss their properties and provide an update on the work being done. As examples of the applications of XCS-DR1, we mention the 17 fossil groups/clusters identified with the help of the Sloan Digital Sky Survey. Their brightest galaxies have stellar populations and star-formation histories which are similar to normal brightest cluster galaxies, but their stellar masses are significantly larger and correspond to a much bigger fraction of the total group/cluster optical luminosity. We also highlight the 15 clusters expected to be also detected by the Planck satellite, and characterize the expected overlap between the final XCS and Planck cluster catalogues.

  20. The Swift AGN and Cluster Survey. II. Cluster Confirmation with SDSS Data

    NASA Astrophysics Data System (ADS)

    Griffin, Rhiannon D.; Dai, Xinyu; Kochanek, Christopher S.; Bregman, Joel N.

    2016-01-01

    We study 203 (of 442) Swift AGN and Cluster Survey extended X-ray sources located in the SDSS DR8 footprint to search for galaxy over-densities in three-dimensional space using SDSS galaxy photometric redshifts and positions near the Swift cluster candidates. We find 104 Swift clusters with a >3σ galaxy over-density. The remaining targets are potentially located at higher redshifts and require deeper optical follow-up observations for confirmation as galaxy clusters. We present a series of cluster properties including the redshift, brightest cluster galaxy (BCG) magnitude, BCG-to-X-ray center offset, optical richness, and X-ray luminosity. We also detect red sequences in ˜85% of the 104 confirmed clusters. The X-ray luminosity and optical richness for the SDSS confirmed Swift clusters are correlated and follow previously established relations. The distribution of the separations between the X-ray centroids and the most likely BCG is also consistent with expectation. We compare the observed redshift distribution of the sample with a theoretical model, and find that our sample is complete for z ≲ 0.3 and is still 80% complete up to z ≃ 0.4, consistent with the SDSS survey depth. These analysis results suggest that our Swift cluster selection algorithm has yielded a statistically well-defined cluster sample for further study of cluster evolution and cosmology. We also match our SDSS confirmed Swift clusters to existing cluster catalogs, and find 42, 23, and 1 matches in optical, X-ray, and Sunyaev-Zel’dovich catalogs, respectively, and so the majority of these clusters are new detections.

  1. THE CLUSTER LENSING AND SUPERNOVA SURVEY WITH HUBBLE: AN OVERVIEW

    SciTech Connect

    Postman, Marc; Coe, Dan; Bradley, Larry; Koekemoer, Anton; Ogaz, Sara; Riess, Adam; Benitez, Narciso; Molino, Alberto; Donahue, Megan; Ford, Holland; Lemze, Doron; Medezinski, Elinor; Rodney, Steve; Graur, Or; Graves, Genevieve; Jouvel, Stephanie; Moustakas, Leonidas; Rosati, Piero; Umetsu, Keiichi; and others

    2012-04-01

    The Cluster Lensing And Supernova survey with Hubble (CLASH) is a 524-orbit Multi-Cycle Treasury Program to use the gravitational lensing properties of 25 galaxy clusters to accurately constrain their mass distributions. The survey, described in detail in this paper, will definitively establish the degree of concentration of dark matter in the cluster cores, a key prediction of structure formation models. The CLASH cluster sample is larger and less biased than current samples of space-based imaging studies of clusters to similar depth, as we have minimized lensing-based selection that favors systems with overly dense cores. Specifically, 20 CLASH clusters are solely X-ray selected. The X-ray-selected clusters are massive (kT > 5 keV) and, in most cases, dynamically relaxed. Five additional clusters are included for their lensing strength ({theta}{sub Ein} > 35'' at z{sub s} = 2) to optimize the likelihood of finding highly magnified high-z (z > 7) galaxies. A total of 16 broadband filters, spanning the near-UV to near-IR, are employed for each 20-orbit campaign on each cluster. These data are used to measure precise ({sigma}{sub z} {approx} 0.02(1 + z)) photometric redshifts for newly discovered arcs. Observations of each cluster are spread over eight epochs to enable a search for Type Ia supernovae at z > 1 to improve constraints on the time dependence of the dark energy equation of state and the evolution of supernovae. We present newly re-derived X-ray luminosities, temperatures, and Fe abundances for the CLASH clusters as well as a representative source list for MACS1149.6+2223 (z 0.544).

  2. Spitzer Survey of the Karin Cluster Asteroids

    NASA Astrophysics Data System (ADS)

    Harris, Alan W.; Mueller, M.; Lisse, C.; Cheng, A.; Osip, D.

    2007-10-01

    The Karin cluster is one of the youngest known families of main-belt asteroids, dating back to a collisional event only 5.8 Myr ago. Using the Spitzer Space Telescope we have sampled the thermal continua of 17 Karin cluster asteroids, down to the smallest members discovered so far, in order to derive accurate sizes and study the physical properties of their surfaces. The albedos of the observed Karins appear to be very similar. The albedos, pv, have a mean of 0.17 and a standard deviation of 0.04, compared to pv = 0.15 ± 0.05 for 832 Karin itself (for H = 11.2 ± 0.3). The derived diameters range from 20 km for 832 Karin to 1.9 km for 93690, with uncertainties of 10%. The Karins data show no evidence of albedo dependence on size, and the small range of albedos is consistent with all program targets being S-type bodies. There is some evidence for higher values of thermal inertia amongst the smaller family members, which may be indicative of coarser regolith. These results are preliminary, pending outstanding Spitzer observations and further analysis. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA.

  3. The C4 clustering algorithm: Clusters of galaxies in the Sloan Digital Sky Survey

    SciTech Connect

    Miller, Christopher J.; Nichol, Robert; Reichart, Dan; Wechsler, Risa H.; Evrard, August; Annis, James; McKay, Timothy; Bahcall, Neta; Bernardi, Mariangela; Boehringer, Hans; Connolly, Andrew; Goto, Tomo; Kniazev, Alexie; Lamb, Donald; Postman, Marc; Schneider, Donald; Sheth, Ravi; Voges, Wolfgang; /Cerro-Tololo InterAmerican Obs. /Portsmouth U., ICG /North Carolina U. /Chicago U., Astron. Astrophys. Ctr. /Chicago U., EFI /Michigan U. /Fermilab /Princeton U. Observ. /Garching, Max Planck Inst., MPE /Pittsburgh U. /Tokyo U., ICRR /Baltimore, Space Telescope Sci. /Penn State U. /Chicago U. /Stavropol, Astrophys. Observ. /Heidelberg, Max Planck Inst. Astron. /INI, SAO

    2005-03-01

    We present the ''C4 Cluster Catalog'', a new sample of 748 clusters of galaxies identified in the spectroscopic sample of the Second Data Release (DR2) of the Sloan Digital Sky Survey (SDSS). The C4 cluster-finding algorithm identifies clusters as overdensities in a seven-dimensional position and color space, thus minimizing projection effects that have plagued previous optical cluster selection. The present C4 catalog covers {approx}2600 square degrees of sky and ranges in redshift from z = 0.02 to z = 0.17. The mean cluster membership is 36 galaxies (with redshifts) brighter than r = 17.7, but the catalog includes a range of systems, from groups containing 10 members to massive clusters with over 200 cluster members with redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L{sub r}), velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multi-color mock SDSS galaxy catalogs, empirically constructed from the {Lambda}CDM Hubble Volume (HV) Sky Survey output, to investigate the sensitivity of the C4 catalog to the various algorithm parameters (detection threshold, choice of passbands and search aperture), as well as to quantify the purity and completeness of the C4 cluster catalog. These mock catalogs indicate that the C4 catalog is {approx_equal}90% complete and 95% pure above M{sub 200} = 1 x 10{sup 14} h{sup -1}M{sub {circle_dot}} and within 0.03 {le} z {le} 0.12. Using the SDSS DR2 data, we show that the C4 algorithm finds 98% of X-ray identified clusters and 90% of Abell clusters within 0.03 {le} z {le} 0.12. Using the mock galaxy catalogs and the full HV dark matter simulations, we show that the L{sub r} of a cluster is a more robust estimator of the halo mass (M{sub 200}) than the galaxy line-of-sight velocity dispersion or the richness of the cluster. However, if we

  4. The ACS Fornax Cluster Survey. XI. Catalog of Globular Cluster Candidates

    NASA Astrophysics Data System (ADS)

    Jordán, Andrés; Peng, Eric W.; Blakeslee, John P.; Côté, Patrick; Eyheramendy, Susana; Ferrarese, Laura

    2015-11-01

    We present catalogs of globular cluster (GC) candidates for 43 galaxies from the ACS Fornax Cluster survey, a program designed to carry out imaging of early-type members of the Fornax cluster using the Advanded Camera for Surveys (ACS) on board the Hubble Space Telescope. The procedure to select bona fide GC candidates from the full list of detections is based on model-based clustering methods, similar to those adopted for a survey of 100 galaxies in the Virgo cluster, the ACS Virgo Cluster Survey. For each detected source, we measure its position, magnitudes in the F475W (≈Sloan g) and F850LP (≈Sloan z) bandpasses, half-light radii obtained by fitting point-spread function-convolved King models to the observed light distribution, and an estimate of the probabilty {p}{GC} that each cataloged source is a GC. These measurements are presented for 9136 sources, of which 6275 have {p}{GC}≥slant 0.5, and are thus likely GCs. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  5. Cosmological Constraints from the Red-Sequence Cluster Survey

    NASA Astrophysics Data System (ADS)

    Gladders, Michael D.; Yee, H. K. C.; Majumdar, Subhabrata; Barrientos, L. Felipe; Hoekstra, Henk; Hall, Patrick B.; Infante, Leopoldo

    2007-01-01

    We present a first cosmological analysis of a refined cluster catalog from the Red-Sequence Cluster Survey (RCS). The input cluster sample is derived from the deepest 72.07 deg2 of the RCS images, which probe to the highest redshift and lowest mass limits. The catalog contains 956 clusters over 0.35cluster richness and richness error. The calibration of the survey images has been extensively cross-checked against publicly available Sloan Digital Sky Survey imaging, and the cluster redshifts and richness that result from this well-calibrated subset of data are robust. We analyze the cluster sample via a general self-calibration technique. We fit simultaneously for the matter density, Ωm, the normalization of the power spectrum, σ8, and four parameters describing the calibration of cluster richness to mass, its evolution with redshift, and scatter in the mass-richness relation. The principal goal of this general analysis is to establish the consistency (or lack thereof) between the fitted parameters (both cosmological and cluster mass observables) and available results on both from independent measures. From an unconstrained analysis, the derived values of Ωm and σ8 are 0.31+0.11-0.10 and 0.67+0.18-0.13, respectively. An analysis including Gaussian priors on the slope and zero point of the mass-richness relation gives very similar results: 0.30+0.12-0.11 and 0.70+0.27-0.15. Both analyses are in acceptable agreement with the current literature. The derived parameters describing the mass-richness relation in the unconstrained fit are also eminently reasonable and in good agreement with existing follow-up data on both the RCS-1 and other cluster samples. Our results directly demonstrate that future surveys (optical and otherwise), with much larger samples of clusters, can give constraints competitive with other probes of cosmology. Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National

  6. Hα star formation rates of z > 1 galaxy clusters in the IRAC shallow cluster survey

    SciTech Connect

    Zeimann, Gregory R.; Stanford, S. A.; Brodwin, Mark; Gonzalez, Anthony H.; Mancone, Conor; Snyder, Gregory F.; Stern, Daniel; Eisenhardt, Peter; Dey, Arjun; Moustakas, John

    2013-12-20

    We present Hubble Space Telescope near-IR spectroscopy for 18 galaxy clusters at 1.0 Cluster Survey. We use Wide Field Camera 3 grism data to spectroscopically identify Hα emitters in both the cores of galaxy clusters as well as in field galaxies. We find a large cluster-to-cluster scatter in the star formation rates within a projected radius of 500 kpc, and many of our clusters (∼60%) have significant levels of star formation within a projected radius of 200 kpc. A stacking analysis reveals that dust reddening in these star-forming galaxies is positively correlated with stellar mass and may be higher in the field than the cluster at a fixed stellar mass. This may indicate a lower amount of gas in star-forming cluster galaxies than in the field population. Also, Hα equivalent widths of star-forming galaxies in the cluster environment are still suppressed below the level of the field. This suppression is most significant for lower mass galaxies (log M {sub *} < 10.0 M {sub ☉}). We therefore conclude that environmental effects are still important at 1.0 clusters with log M {sub *} ≲ 10.0 M {sub ☉}.

  7. Environmental Field Surveys, EMF Rapid Program, Engineering Project No.3

    SciTech Connect

    Enertech Consultants

    1996-04-01

    The EMF Research and Public Information Dissemination Program (RAPID) includes several engineering research in the area of exposure assessment and source characterization. RAPID engineering project No. 3: ''Environmental Field Surveys'' was performed to obtain information on the levels and characteristics of different environments, for which only limited data were available, especially in comparison to magnetic field data for the residential environment and for electric utility facilities, such as power lines and substations. This project was also to provide information on the contribution of various field sources in the surveyed environments. Magnetic field surveys were performed at four sites for each of five environments: schools, hospitals, office buildings, machine shops, and grocery stores. Of the twenty sites surveyed, 11 were located in the San Francisco Bay Area and 9 in Massachusetts. The surveys used a protocol based on magnetic field measurements and observation of activity patterns, designed to provide estimates of magnetic field exposure by type of people and by type of sources. The magnetic field surveys conducted by this project produced a large amount of data which will form a part of the EMF measurement database Field and exposure data were obtained separately for ''area exposure'' and ''at exposure points''. An exposure point is a location where persons engage in fixed, site specific activities near a local source that creates a significant increase in the area field. The area field is produced by ''area sources'', whose location and field distribution is in general not related to the location of the people in the area.

  8. Tests of the Las Campanas Distant Cluster Survey from Confirmation Observations for the ESO Distant Cluster Survey

    NASA Astrophysics Data System (ADS)

    Gonzalez, Anthony H.; Zaritsky, Dennis; Simard, Luc; Clowe, Doug; White, Simon D. M.

    2002-11-01

    The ESO Distant Cluster Survey (EDisCS) is a photometric and spectroscopic study of the galaxy cluster population at two epochs, z~=0.5 and z~=0.8, drawn from the Las Campanas Distant Cluster Survey (LCDCS). We report results from the initial candidate-confirmation stage of the program and use these results to probe the properties of the LCDCS. Of the 30 candidates targeted, we find statistically significant overdensities of red galaxies near 28. Of the 10 additional candidates serendipitously observed within the fields of the targeted 30, we detect red galaxy overdensities near six. We test the robustness of the published LCDCS estimated redshifts to misidentification of the brightest cluster galaxy (BCG) in the survey data and measure the spatial alignment of the published cluster coordinates, the peak red galaxy overdensity, and the BCG. We conclude that for LCDCS clusters out to z~0.8, (1) the LCDCS coordinates agree with the centroid of the red galaxy overdensity to within 25" (~150 h-1 kpc) for 34 out of 37 candidates with 3 σ galaxy overdensities, (2) BCGs are typically coincident with the centroid of the red galaxy population to within a projected separation of 200 h-1 kpc (32 out of 34 confirmed candidates), (3) the red galaxy population is strongly concentrated, and (4) the misidentification of the BCG in the LCDCS causes a redshift error greater than 0.1 in 15%-20% of the LCDCS candidates. These findings together help explain the success of the surface brightness fluctuations detection method. Based on observations obtained in visitor and service modes at the ESO Very Large Telescope (VLT) as part of the Large Program 166.A-0162 (the ESO Distant Cluster Survey).

  9. Optical galaxy clusters in the Deep Lens Survey

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Wittman, D.; Dawson, W.

    2014-04-01

    We present the first sample of 882 optically selected galaxy clusters in the Deep Lens Survey (DLS), selected with the Bayesian Cluster Finder. We create mock DLS data to assess completeness and purity rates, and find that both are at least 70 per cent within 0.1 ≤ z ≤ 1.2 for clusters with M200 ≥ 1.2 × 1014 M⊙. We verified the integrity of the sample by performing several comparisons with other optical, weak lensing, X-ray and spectroscopic surveys which overlap the DLS footprint: the estimated redshifts are consistent with the spectroscopic redshifts of known clusters (for z > 0.25 where saturation in the DLS is not an issue); our richness estimates in combination with a previously calibrated richness-mass relation yield individual cluster mass estimates consistent with available Smithsonian Hectospec Lensing Survey dynamical mass estimates; synthetic mass maps made from the optical mass estimates are correlated (>3σ significance) with the weak lensing mass maps; and the mass function thus derived is consistent with theoretical predictions for the cold dark matter scenario. With the verified sample, we investigated correlations between the brightest cluster galaxy (BCG) properties and the host cluster properties within a broader range in redshift (0.25 ≤ z ≤ 0.8) and mass (≥2.4 × 1014 M⊙) than in previous work. We find that the slope of the BCG magnitude-redshift relation throughout this redshift range is consistent with that found at lower redshifts. This result supports an extrapolation to higher redshift of passive evolution of the BCG within the hierarchical scenario.

  10. Calibrated propensity score method for survey nonresponse in cluster sampling

    PubMed Central

    Kim, Jae Kwang; Kwon, Yongchan; Paik, Myunghee Cho

    2016-01-01

    Weighting adjustment is commonly used in survey sampling to correct for unit nonresponse. In cluster sampling, the missingness indicators are often correlated within clusters and the response mechanism is subject to cluster-specific nonignorable missingness. Based on a parametric working model for the response mechanism that incorporates cluster-specific nonignorable missingness, we propose a method of weighting adjustment. We provide a consistent estimator of the mean or totals in cases where the study variable follows a generalized linear mixed-effects model. The proposed method is robust in the sense that the consistency of the estimator does not require correct specification of the functional forms of the response and outcome models. A consistent variance estimator based on Taylor linearization is also proposed. Numerical results, including a simulation and a real-data application, are presented.

  11. THE STELLAR MASS GROWTH OF BRIGHTEST CLUSTER GALAXIES IN THE IRAC SHALLOW CLUSTER SURVEY

    SciTech Connect

    Lin, Yen-Ting; Brodwin, Mark; Gonzalez, Anthony H.; Bode, Paul; Eisenhardt, Peter R. M.; Stanford, S. A.; Vikhlinin, Alexey

    2013-07-01

    The details of the stellar mass assembly of brightest cluster galaxies (BCGs) remain an unresolved problem in galaxy formation. We have developed a novel approach that allows us to construct a sample of clusters that form an evolutionary sequence, and have applied it to the Spitzer IRAC Shallow Cluster Survey (ISCS) to examine the evolution of BCGs in progenitors of present-day clusters with mass of (2.5-4.5) Multiplication-Sign 10{sup 14} M{sub Sun }. We follow the cluster mass growth history extracted from a high resolution cosmological simulation, and then use an empirical method that infers the cluster mass based on the ranking of cluster luminosity to select high-z clusters of appropriate mass from ISCS to be progenitors of the given set of z = 0 clusters. We find that, between z = 1.5 and 0.5, the BCGs have grown in stellar mass by a factor of 2.3, which is well-matched by the predictions from a state-of-the-art semi-analytic model. Below z = 0.5 we see hints of differences in behavior between the model and observation.

  12. The XXL survey: first results on clusters of galaxy

    NASA Astrophysics Data System (ADS)

    Pacaud, Florian

    2016-07-01

    With a total geometric area of 50deg2, XXL is the largest contiguous survey undertaken by the XMM-Newton satellite. The final survey catalogues are expected to contain ~25000 AGNs down to a flux limit of 3e-15 erg/s/cm2 and ~500 groups and clusters of galaxies up to a redshift of z~1.5. The first results of the survey focus on a sub-sample of the 100 brightest galaxy clusters and have recently been released to the public. In this contribution, I will first describe the sample and the modeling of its selection function. Then, I will discuss some of the most significant early scientific results based on the catalogue, namely the measured scaling relations, the baryon budget of XXL groups, the detection of superstructures and the cosmological implications of the sample.

  13. New Galactic star clusters discovered in the VVV survey

    NASA Astrophysics Data System (ADS)

    Borissova, J.; Bonatto, C.; Kurtev, R.; Clarke, J. R. A.; Peñaloza, F.; Sale, S. E.; Minniti, D.; Alonso-García, J.; Artigau, E.; Barbá, R.; Bica, E.; Baume, G. L.; Catelan, M.; Chenè, A. N.; Dias, B.; Folkes, S. L.; Froebrich, D.; Geisler, D.; de Grijs, R.; Hanson, M. M.; Hempel, M.; Ivanov, V. D.; Kumar, M. S. N.; Lucas, P.; Mauro, F.; Moni Bidin, C.; Rejkuba, M.; Saito, R. K.; Tamura, M.; Toledo, I.

    2011-08-01

    Context. VISTA Variables in the Vía Láctea (VVV) is one of the six ESO Public Surveys operating on the new 4-m Visible and Infrared Survey Telescope for Astronomy (VISTA). VVV is scanning the Milky Way bulge and an adjacent section of the disk, where star formation activity is high. One of the principal goals of the VVV Survey is to find new star clusters of differentages. Aims: In order to trace the early epochs of star cluster formation we concentrated our search in the directions to those of known star formation regions, masers, radio, and infrared sources. Methods: The disk area covered by VVV was visually inspected using the pipeline processed and calibrated KS-band tile images for stellar overdensities. Subsequently, we examined the composite JHKS and ZJKS color images of each candidate. PSF photometry of 15 × 15 arcmin fields centered on the candidates was then performed on the Cambridge Astronomy Survey Unit reduced images. After statistical field-star decontamination, color-magnitude and color-color diagrams were constructed and analyzed. Results: We report the discovery of 96 new infrared open clusters and stellar groups. Most of the new cluster candidates are faint and compact (with small angular sizes), highly reddened, and younger than 5 Myr. For relatively well populated cluster candidates we derived their fundamental parameters such as reddening, distance, and age by fitting the solar-metallicity Padova isochrones to the color-magnitude diagrams. Based on observations gathered with VIRCAM, VISTA of the ESO as part of observing programs 172.B-2002Appendix A is available in electronic form at http://www.aanda.orgTable 1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/532/A131

  14. Weak lensing survey of galaxy clusters in the CFHTLS Deep

    NASA Astrophysics Data System (ADS)

    Gavazzi, R.; Soucail, G.

    2007-02-01

    Aims: We present a weak lensing search of galaxy clusters in the 4 deg2 of the CFHT Legacy Survey Deep. This work aims at building a mass-selected sample of clusters with well controlled selection effects. This present survey is a preliminary step toward a full implementation in the forthcoming 170 deg2 of the CFHTLS Wide survey. Methods: We use the deep i' band images observed under subarcsecond seeing conditions to perform weak lensing mass reconstructions and to identify high convergence peaks. Thanks to the availability of deep u^*g'r'i'z' exposures, sources are selected from their photometric redshifts in the weak lensing analysis. We also use lensing tomography to derive an estimate of the lens redshift. After considering the raw statistics of peaks we check whether they can be associated to a clear optical counterpart or to published X-ray selected clusters. Results: Among the 14 peaks found above a signal-to-noise detection threshold ν=3.5, nine are secure detections with estimated redshift 0.1⪉ z_l⪉0.7 and a velocity dispersion 450⪉σ_v⪉ 700 {km s}-1. This low mass range is accessible thanks to the high density of background sources. Considering the intersection between the shear-selected clusters and XMM-LSS X-ray clusters in the D1 field, we observe that the ICM gas in these low-mass clusters (T_X˜1{-}2 keV) is not hotter than the temperature inferred from shear, this trend being different for published massive clusters. A more extended weak lensing survey, with higher statistics of mass structures will be a promising way to bypass several of the problems related to standard detection methods based on the complex physics of baryons. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of

  15. Can a galaxy redshift survey measure dark energy clustering?

    SciTech Connect

    Takada, Masahiro

    2006-08-15

    A wide-field galaxy redshift survey allows one to probe galaxy clustering at largest spatial scales, which carries invaluable information on horizon-scale physics complementarily to the cosmic microwave background (CMB). Assuming the planned survey consisting of z{approx}1 and z{approx}3 surveys with areas of 2000 and 300 deg.{sup 2}, respectively, we study the prospects for probing dark energy clustering from the measured galaxy power spectrum, assuming the dynamical properties of dark energy are specified in terms of the equation of state and the effective sound speed c{sub e} in the context of an adiabatic cold dark dominated matter model. The dark energy clustering adds a power to the galaxy power spectrum amplitude at spatial scales greater than the sound horizon, and the enhancement is sensitive to redshift evolution of the net dark energy density, i.e. the equation of state. We find that the galaxy survey, when combined with CMB expected from the Planck satellite mission, can distinguish dark energy clustering from a smooth dark energy model such as the quintessence model (c{sub e}=1), when c{sub e} < or approx. 0.04 (0.02) in the case of the constant equation of state w{sub 0}=-0.9 (-0.95). An ultimate full-sky survey of z{approx}1 galaxies allows the detection when c{sub e}(less-or-similar sign)0.08 (0.04) for w{sub 0}=0.9 (-0.95). These forecasts show a compatible power with an all-sky CMB and galaxy cross correlation that probes the integrated Sachs-Wolfe effect. We also investigate a degeneracy between the dark energy clustering and the nonrelativistic neutrinos implied from the neutrino oscillation experiments, because the two effects both induce a scale-dependent modification in the galaxy power spectrum shape at largest spatial scales accessible from the galaxy survey. It is shown that a wider redshift coverage can efficiently separate the two effects by utilizing the different redshift dependences, where dark energy clustering is apparent only at

  16. RAPID DYNAMICAL MASS SEGREGATION AND PROPERTIES OF FRACTAL STAR CLUSTERS

    SciTech Connect

    Yu Jincheng; Chen Li; De Grijs, Richard

    2011-05-01

    We investigate the evolution of young star clusters using N-body simulations. We confirm that subvirial and fractal-structured clusters will dynamically mass segregate on a short timescale (within 0.5 Myr). We adopt a modified minimum-spanning-tree method to measure the degree of mass segregation, demonstrating that the stars escaping from a cluster's potential are important for the temporal dependence of mass segregation in the cluster. The form of the initial velocity distribution will also affect the degree of mass segregation. If it depends on radius, the outer parts of the cluster would expand without undergoing collapse. In velocity space, we find 'inverse mass segregation', which indicates that massive stars have higher velocity dispersions than their lower-mass counterparts.

  17. A SURVEY FOR PLANETARY NEBULAE IN M31 GLOBULAR CLUSTERS

    SciTech Connect

    Jacoby, George H.; De Marco, Orsola; Lee, Myung Gyoon; Herrmann, Kimberly A.; Hwang, Ho Seong; Davies, James E.; Kaplan, Evan E-mail: rbc@astro.psu.edu E-mail: mglee@astrog.snu.ac.kr E-mail: hhwang@cfa.harvard.edu E-mail: evanskaplan@gmail.com

    2013-05-20

    We report the results of an [O III] {lambda}5007 spectroscopic survey for planetary nebulae (PNe) located within the star clusters of M31. By examining R {approx} 5000 spectra taken with the WIYN+Hydra spectrograph, we identify 3 PN candidates in a sample of 274 likely globular clusters, 2 candidates in objects which may be globular clusters, and 5 candidates in a set of 85 younger systems. The possible PNe are all faint, between {approx}2.5 and {approx}6.8 mag down the PN luminosity function, and, partly as a consequence of our selection criteria, have high excitation, with [O III] {lambda}5007 to H{beta} ratios ranging from 2 to {approx}> 12. We discuss the individual candidates, their likelihood of cluster membership, and the possibility that they were formed via binary interactions within the clusters. Our data are consistent with the suggestion that PN formation within globular clusters correlates with binary encounter frequency, though, due to the small numbers and large uncertainties in the candidate list, this study does not provide sufficient evidence to confirm the hypothesis.

  18. Clustering of smoking, alcohol drinking and cannabis use in adolescents in a rapidly developing country

    PubMed Central

    Faeh, David; Viswanathan, Bharathi; Chiolero, Arnaud; Warren, Wick; Bovet, Pascal

    2006-01-01

    Background Smoking, alcohol drinking and cannabis use ("risk behaviors") are often initiated at a young age but few epidemiological studies have assessed their joined prevalence in children in developing countries. This study aims at examining the joint prevalence of these behaviors in adolescents in the Seychelles, a rapidly developing country in the Indian Ocean. Methods Cross-sectional survey in a representative sample of secondary school students using an anonymous self-administered questionnaire (Global Youth Tobacco Survey). The questionnaire was completed by 1,321 (92%) of 1,442 eligible students aged 11 to 17 years. Main variables of interest included smoking cigarettes on ≥1 day in the past 30 days; drinking any alcohol beverage on ≥1 day in the past 30 days and using cannabis at least once in the past 12 months. Results In boys and girls, respectively, prevalence (95% CI) was 30% (26–34)/21% (18–25) for smoking, 49% (45–54)/48% (43–52) for drinking, and 17% (15–20)/8% (6–10) for cannabis use. The prevalence of all these behaviors increased with age. Smokers were two times more likely than non-smokers to drink and nine times more likely to use cannabis. Drinkers were three times more likely than non-drinkers to smoke or to use cannabis. Comparison of observed versus expected frequencies of combination categories demonstrated clustering of these risk behaviors in students (P < 0.001). Conclusion Smoking, drinking and cannabis use were common and clustered among adolescents of a rapidly developing country. These findings stress the need for early and integrated prevention programs. PMID:16803621

  19. Clustering and community detection in directed networks: A survey

    NASA Astrophysics Data System (ADS)

    Malliaros, Fragkiskos D.; Vazirgiannis, Michalis

    2013-12-01

    Networks (or graphs) appear as dominant structures in diverse domains, including sociology, biology, neuroscience and computer science. In most of the aforementioned cases graphs are directed - in the sense that there is directionality on the edges, making the semantics of the edges nonsymmetric as the source node transmits some property to the target one but not vice versa. An interesting feature that real networks present is the clustering or community structure property, under which the graph topology is organized into modules commonly called communities or clusters. The essence here is that nodes of the same community are highly similar while on the contrary, nodes across communities present low similarity. Revealing the underlying community structure of directed complex networks has become a crucial and interdisciplinary topic with a plethora of relevant application domains. Therefore, naturally there is a recent wealth of research production in the area of mining directed graphs - with clustering being the primary method sought and the primary tool for community detection and evaluation. The goal of this paper is to offer an in-depth comparative review of the methods presented so far for clustering directed networks along with the relevant necessary methodological background and also related applications. The survey commences by offering a concise review of the fundamental concepts and methodological base on which graph clustering algorithms capitalize on. Then we present the relevant work along two orthogonal classifications. The first one is mostly concerned with the methodological principles of the clustering algorithms, while the second one approaches the methods from the viewpoint regarding the properties of a good cluster in a directed network. Further, we present methods and metrics for evaluating graph clustering results, demonstrate interesting application domains and provide promising future research directions.

  20. Photometric analysis of Galactic Stellar Clusters in VVV Survey

    NASA Astrophysics Data System (ADS)

    Mauro, F.; Moni Bidin, C.; Cohen, R. E.; Geisler, D.; Villanova, S.; Chené, A. N.

    2014-10-01

    We show the preliminary results of the study of the structure of the Horizontal Branch of Liller 1 and some results from the Calcium Triplet method using Ks magnitude applied to several Galactic Globular clusters using data from the VISTA Variables in the Via Lactea Survey (Minniti et al. 2010) and obtained with GeMS/GSAOI. The data are extracted with the new automatic VVV-SkZ_pipeline photometric pipeline (Mauro et al. 2013).

  1. Next generation cosmology: constraints from the Euclid galaxy cluster survey

    NASA Astrophysics Data System (ADS)

    Sartoris, B.; Biviano, A.; Fedeli, C.; Bartlett, J. G.; Borgani, S.; Costanzi, M.; Giocoli, C.; Moscardini, L.; Weller, J.; Ascaso, B.; Bardelli, S.; Maurogordato, S.; Viana, P. T. P.

    2016-06-01

    We study the characteristics of the galaxy cluster samples expected from the European Space Agency's Euclid satellite and forecast constraints on parameters describing a variety of cosmological models. In this paper we use the same method of analysis already adopted in the Euclid Red Book, which is based on the Fisher matrix approach. Based on our analytical estimate of the cluster selection function in the photometric Euclid survey, we forecast the constraints on cosmological parameters corresponding to different extensions of the standard Λ cold dark matter model. Using only Euclid clusters, we find that the amplitude of the matter power spectrum will be constrained to Δσ8 = 0.0014 and the mass density parameter to ΔΩm = 0.0011. The dynamical evolution of dark energy will be constrained to Δw0 = 0.03 and Δwa = 0.2 with free curvature Ωk, resulting in a (w0, wa) figure of merit (FoM) of 291. In combination with Planck cosmic microwave background (CMB) constraints, the amplitude of primordial non-Gaussianity will be constrained to ΔfNL ≃ 6.6 for the local shape scenario. The growth factor parameter γ, which signals deviations from general relativity, will be constrained to Δγ = 0.02, and the neutrino density parameter to ΔΩν = 0.0013 (or Δ∑mν = 0.01). Including the Planck CMB covariance matrix improves dark energy constraints to Δw0 = 0.02, Δwa = 0.07, and a FoM = 802. Knowledge of the observable-cluster mass scaling relation is crucial to reach these accuracies. Imaging and spectroscopic capabilities of Euclid will enable internal mass calibration from weak lensing and the dynamics of cluster galaxies, supported by external cluster surveys.

  2. A neutral hydrogen survey of the Hydra 1 cluster

    NASA Technical Reports Server (NTRS)

    Mcmahon, Pauline; Vangorkom, Jacqueline; Richter, Otto; Ferguson, Henry

    1993-01-01

    We are undertaking a project to image the entire volume of the Hydra 1 cluster of galaxies in neutral hydrogen using the VLA. This involves making a series of pointings spaced 30 min. (the half power beam width) apart, each observed at three velocity settings in order to span the whole velocity range of the cluster. The purpose of this survey is to determine the true distribution, both in space and velocity, of gas-rich systems and hence, to deduce what effects a dense environment may have on the evolution of these systems. Most surveys of clusters to date have been performed on optically selected samples. However, optically selected samples may provide misleading views of the distribution of gas-rich systems, since many low surface brightness galaxies have an abundance of neutral gas (Bothun et al. 1987, Giovanelli & Haynes 1989). The Hydra project is providing the first unbiased view of the HI distribution in a cluster of galaxies. Our 5 sigma sensitivity is 4.1 x 10(exp 7) solar M/beam, (assuming H(sub 0) = 75 km s(exp -1) Mpc(exp -1)) and our velocity resolution is 42 km s(exp -1). We have a spatial resolution of 45 sec., which means that only the largest galaxies are spatially resolved enough to determine HI disk size. Our coverage is about 50 percent of the central region plus eight other fields centered on bright spirals within about 2 deg. of the center.

  3. RCSLenS: The Red Cluster Sequence Lensing Survey

    NASA Astrophysics Data System (ADS)

    Hildebrandt, H.; Choi, A.; Heymans, C.; Blake, C.; Erben, T.; Miller, L.; Nakajima, R.; van Waerbeke, L.; Viola, M.; Buddendiek, A.; Harnois-Déraps, J.; Hojjati, A.; Joachimi, B.; Joudaki, S.; Kitching, T. D.; Wolf, C.; Gwyn, S.; Johnson, N.; Kuijken, K.; Sheikhbahaee, Z.; Tudorica, A.; Yee, H. K. C.

    2016-08-01

    We present the Red-sequence Cluster Lensing Survey (RCSLenS), an application of the methods developed for the Canada France Hawaii Telescope Lensing Survey (CFHTLenS) to the ˜785 deg2, multi-band imaging data of the Red-sequence Cluster Survey 2 (RCS2). This project represents the largest public, sub-arcsecond seeing, multi-band survey to date that is suited for weak gravitational lensing measurements. With a careful assessment of systematic errors in shape measurements and photometric redshifts we extend the use of this data set to allow cross-correlation analyses between weak lensing observables and other data sets. We describe the imaging data, the data reduction, masking, multi-colour photometry, photometric redshifts, shape measurements, tests for systematic errors, and a blinding scheme to allow for more objective measurements. In total we analyse 761 pointings with r-band coverage, which constitutes our lensing sample. Residual large-scale B-mode systematics prevent the use of this shear catalogue for cosmic shear science. The effective number density of lensing sources over an unmasked area of 571.7 deg2 and down to a magnitude limit of r ˜ 24.5 is 8.1 galaxies per arcmin2 (weighted: 5.5 arcmin-2) distributed over 14 patches on the sky. Photometric redshifts based on 4-band griz data are available for 513 pointings covering an unmasked area of 383.5 deg2. We present weak lensing mass reconstructions of some example clusters as well as the full survey representing the largest areas that have been mapped in this way. All our data products are publicly available through CADC at http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/community/rcslens/query.html in a format very similar to the CFHTLenS data release.

  4. The Richness Dependence of Galaxy Cluster Correlations: Results From A Redshift Survey Of Rich APM Clusters

    NASA Technical Reports Server (NTRS)

    Croft, R. A. C.; Dalton, G. B.; Efstathiou, G.; Sutherland, W. J.; Maddox, S. J.

    1997-01-01

    We analyze the spatial clustering properties of a new catalog of very rich galaxy clusters selected from the APM Galaxy Survey. These clusters are of comparable richness and space density to Abell Richness Class greater than or equal to 1 clusters, but selected using an objective algorithm from a catalog demonstrably free of artificial inhomogeneities. Evaluation of the two-point correlation function xi(sub cc)(r) for the full sample and for richer subsamples reveals that the correlation amplitude is consistent with that measured for lower richness APM clusters and X-ray selected clusters. We apply a maximum likelihood estimator to find the best fitting slope and amplitude of a power law fit to x(sub cc)(r), and to estimate the correlation length r(sub 0) (the value of r at which xi(sub cc)(r) is equal to unity). For clusters with a mean space density of 1.6 x 10(exp -6) h(exp 3) MpC(exp -3) (equivalent to the space density of Abell Richness greater than or equal to 2 clusters), we find r(sub 0) = 21.3(+11.1/-9.3) h(exp -1) Mpc (95% confidence limits). This is consistent with the weak richness dependence of xi(sub cc)(r) expected in Gaussian models of structure formation. In particular, the amplitude of xi(sub cc)(r) at all richnesses matches that of xi(sub cc)(r) for clusters selected in N-Body simulations of a low density Cold Dark Matter model.

  5. THE NEXT GENERATION VIRGO CLUSTER SURVEY (NGVS). I. INTRODUCTION TO THE SURVEY

    SciTech Connect

    Ferrarese, Laura; Cote, Patrick; Gwyn, S. D. J.; MacArthur, Lauren A.; McConnachie, Alan W.; Blakeslee, John P.; Cuillandre, Jean-Charles; Peng, Eric W.; Duc, Pierre-Alain; Mei, Simona; Erben, Thomas; Durrell, Patrick R.; Christopher Mihos, J.; Jordan, Andres; Puzia, Thomas H.; Lancon, Ariane; Emsellem, Eric; Balogh, Michael L.; Van Waerbeke, Ludovic; and others

    2012-05-01

    The Next Generation Virgo Cluster Survey (NGVS) is a program that uses the 1 deg{sup 2} MegaCam instrument on the Canada-France-Hawaii Telescope to carry out a comprehensive optical imaging survey of the Virgo cluster, from its core to its virial radius-covering a total area of 104 deg{sup 2}-in the u*griz bandpasses. Thanks to a dedicated data acquisition strategy and processing pipeline, the NGVS reaches a point-source depth of g Almost-Equal-To 25.9 mag (10{sigma}) and a surface brightness limit of {mu}{sub g} {approx} 29 mag arcsec{sup -2} (2{sigma} above the mean sky level), thus superseding all previous optical studies of this benchmark galaxy cluster. In this paper, we give an overview of the technical aspects of the survey, such as areal coverage, field placement, choice of filters, limiting magnitudes, observing strategies, data processing and calibration pipelines, survey timeline, and data products. We also describe the primary scientific topics of the NGVS, which include: the galaxy luminosity and mass functions; the color-magnitude relation; galaxy scaling relations; compact stellar systems; galactic nuclei; the extragalactic distance scale; the large-scale environment of the cluster and its relationship to the Local Supercluster; diffuse light and the intracluster medium; galaxy interactions and evolutionary processes; and extragalactic star clusters. In addition, we describe a number of ancillary programs dealing with 'foreground' and 'background' science topics, including the study of high-inclination trans-Neptunian objects; the structure of the Galactic halo in the direction of the Virgo Overdensity and Sagittarius Stream; the measurement of cosmic shear, galaxy-galaxy, and cluster lensing; and the identification of distant galaxy clusters, and strong-lensing events.

  6. Nonlinear clustering in the CfA redshift survey

    SciTech Connect

    Alimi, J.; Blanchard, A.; Schaeffer, R. Ecole Polytechnique, Palaiseau Paris VII Universite CEA, Service de Physique Theorique de Saclay, Gif-sur-Yvette )

    1990-01-01

    The probability of finding a hole in a randomly placed sphere of volume V has been considered in the Cfa survey by numerous authors. The main emphasis of these studies has been on a scaling law derived from the assumption of hierarchical clustering. Here, the counts in cell statistics P(N) in the CfA redshift survey are analyzed. The results show that the general behavior of the P(N) can be predicted on the sole assumption of the hierarchical hypothesis. Scaling forms can then be predicted which appear to be verified to a fairly good extent in the Cfa redshift survey. This implies that the hypothesis of scale-invariant many-body correlations function provides for a satisfactory description of the count-in-cell statistics. 23 refs.

  7. The XMM Cluster Survey: A Massive Galaxy Cluster at z = 1.45

    SciTech Connect

    Stanford, S A; Romer, A K; Sabirli, K; Davidson, M; Hilton, M; Viana, P P; Collins, C A; Kay, S T; Liddle, A R; Mann, R G; Miller, C J; Nichol, R C; West, M J; Conselice, C J; Spinrad, H; Stern, D; Bundy, K

    2006-05-24

    We report the discovery of XMMXCS J2215.9-1738, a massive galaxy cluster at z = 1.45, which was found in the XMM Cluster Survey. The cluster candidate was initially identified as an extended X-ray source in archival XMM data. Optical spectroscopy shows that 6 galaxies within a {approx}60 arcsec diameter region lie at z = 1.45 {+-} 0.01. Model fits to the X-ray spectra of the extended emission yield kT = 7.4{sub -1.8}{sup +2.7} keV (90% confidence); if there is an undetected central X-ray point source then kT = 6.5{sub -1.8}{sup +2.6} keV. The bolometric X-ray luminosity is L{sub x} = 4.4{sub -0.6}{sup +0.8} x 10{sup 44} ergs s{sup -1} over a 2 Mpc radial region. The measured T{sub x}, which is the highest for any known cluster at z > 1, suggests that this cluster is relatively massive for such a high redshift. The redshift of XMMXCS J2215.9-1738 is the highest currently known for a spectroscopically-confirmed cluster of galaxies.

  8. The X-ray luminosity functions of Abell clusters from the Einstein Cluster Survey

    NASA Technical Reports Server (NTRS)

    Burg, R.; Giacconi, R.; Forman, W.; Jones, C.

    1994-01-01

    We have derived the present epoch X-ray luminosity function of northern Abell clusters using luminosities from the Einstein Cluster Survey. The sample is sufficiently large that we can determine the luminosity function for each richness class separately with sufficient precision to study and compare the different luminosity functions. We find that, within each richness class, the range of X-ray luminosity is quite large and spans nearly a factor of 25. Characterizing the luminosity function for each richness class with a Schechter function, we find that the characteristic X-ray luminosity, L(sub *), scales with richness class as (L(sub *) varies as N(sub*)(exp gamma), where N(sub *) is the corrected, mean number of galaxies in a richness class, and the best-fitting exponent is gamma = 1.3 +/- 0.4. Finally, our analysis suggests that there is a lower limit to the X-ray luminosity of clusters which is determined by the integrated emission of the cluster member galaxies, and this also scales with richness class. The present sample forms a baseline for testing cosmological evolution of Abell-like clusters when an appropriate high-redshift cluster sample becomes available.

  9. An X-ray survey of clusters of galaxies. IV - A survey of southern clusters and a compilation of upper limits for both Abell and southern clusters

    NASA Technical Reports Server (NTRS)

    Kowalski, M. P.; Cruddace, R. G.; Wood, K. S.; Ulmer, M. P.

    1984-01-01

    The results of the HEAO 1 A-1 X-ray survey of galaxy clusters are reported. X-ray error boxes and intensities are presented for all clusters in the Abell catalog and for the catalog of southern clusters and groups compiled by Duus and Newell (1977). A correlation is derived on the basis of the X-ray luminosity function for 2-6 keV which may be used to calculate the contribution of clusters to the diffuse X-ray background at different energies. The cluster X-ray is estimated to be 9.3 percent (+ 1.9 or - 1.5 percent). Correlations between X-ray luminosity and other cluster properties are exmained, and it is found that the distribution of upper limits may be applied to obtaining a more precise estimate of the average X-ray luminosity of clusters. The Abell richness class and southern cluster concentrations were strongly correlated with X-ray luminosity. Correlations between optical x-ray luminosity and optical radius velocity dispersion, spiral fraction, and radio power are analyzed. The evidence for all these correlations was considered to be weak because of poor scatter in the data.

  10. THE NEXT GENERATION VIRGO CLUSTER SURVEY. IV. NGC 4216: A BOMBARDED SPIRAL IN THE VIRGO CLUSTER

    SciTech Connect

    Paudel, Sanjaya; Duc, Pierre-Alain; Ferriere, Etienne; Cuillandre, Jean-Charles; Mihos, J. Christopher; Vollmer, Bernd; Balogh, Michael L.; Carlberg, Ray G.; Boissier, Samuel; Boselli, Alessandro; Durrell, Patrick R.; Emsellem, Eric; Michel-Dansac, Leo; Mei, Simona; Van Driel, Wim

    2013-04-20

    The final stages of mass assembly of present-day massive galaxies are expected to occur through the accretion of multiple satellites. Cosmological simulations thus predict a high frequency of stellar streams resulting from this mass accretion around the massive galaxies in the Local Volume. Such tidal streams are difficult to observe, especially in dense cluster environments, where they are readily destroyed. We present an investigation into the origins of a series of interlaced narrow filamentary stellar structures, loops and plumes in the vicinity of the Virgo Cluster, edge-on spiral galaxy, NGC 4216 that were previously identified by the Blackbird telescope. Using the deeper, higher-resolution, and precisely calibrated optical CFHT/MegaCam images obtained as part of the Next Generation Virgo Cluster Survey (NGVS), we confirm the previously identified features and identify a few additional structures. The NGVS data allowed us to make a physical study of these low surface brightness features and investigate their origin. The likely progenitors of the structures were identified as either already cataloged Virgo Cluster Catalog dwarfs or newly discovered satellites caught in the act of being destroyed. They have the same g - i color index and likely contain similar stellar populations. The alignment of three dwarfs along an apparently single stream is intriguing, and we cannot totally exclude that these are second-generation dwarf galaxies being born inside the filament from the debris of an original dwarf. The observed complex structures, including in particular a stream apparently emanating from a satellite of a satellite, point to a high rate of ongoing dwarf destruction/accretion in the region of the Virgo Cluster where NGC 4216 is located. We discuss the age of the interactions and whether they occurred in a group that is just falling into the cluster and shows signs of the so-called pre-processing before it gets affected by the cluster environment, or in a

  11. Sunyaev Zel'dovich galaxy cluster wide surveys for cosmology

    NASA Astrophysics Data System (ADS)

    Juin, J.-B.; Pires, S.; Yvon, D.; Refregier, A.; Yeche, C.; Moudden, Y.; Anthoine, S.; Pierpaoli, E.

    The observation of galaxy cluster population in milimeter wavelength through their Sunyaev Zel'dovich signal, both at low and high redshifts will provide the large sample needed to perform statistical studies of both intra-cluster physics and cosmology allowing a better understanding of universe dark-components: dark- matter density and dark-energy equation of state. Starting now, Olimpo, South Pole Telescope, Planck-HFI, APEX-SZ and Atacama Cosmology Telescope are world- class instruments dedicated to perform such surveys. After the technological challenge overcomed by state-of-art telescopes and bolometer camera, achievement of milimeter wide surveys need dedicated alogrithms to extract the SZ signal of galaxy cluster from foregrounds and backgrounds contaminants. This difficulty arise complex selection effects that have to be understood properly to allow optimal constraints calculation on physical models. Presented results are a summary of both articles: Pires et al. 2006 and Juin et al. 2007 published in Astronomy and Astrophics. In the first paper we present an efficient detection pipeline to extract SZ signal of galaxy clusters from multi-band millimeter maps. The pipeline core is an Independant Component Analysis algorithm that will isolate SZ signal from other physical contaminants (CMB anisotropies, galactic dust and SCUBA-like point sources) considered as statistically independant physical signals. While ICA algorithm is able to efficiently separate SZ signal from the mixture of physical signals, noise still remains in the SZ recovered map implying the necessity of a denoising step after the ICA. We used different classical filters (gaussian, wiener) and a state-of-art non-linear multi-scale entropy filtering, ME-FDR, with false-detection rate automatized threshold choice in each scale. This non-linear filtering showed to be an efficient method to avoid false detections of point sources that could have succeed the ICA selection and show up in the

  12. THE RED-SEQUENCE CLUSTER SURVEY-2 (RCS-2): SURVEY DETAILS AND PHOTOMETRIC CATALOG CONSTRUCTION

    SciTech Connect

    Gilbank, David G.; Gladders, M. D.; Yee, H. K. C.; Hsieh, B. C.

    2011-03-15

    The second Red-sequence Cluster Survey (RCS-2) is a {approx}1000 deg{sup 2}, multi-color imaging survey using the square-degree imager, MegaCam, on the Canada-France-Hawaii Telescope. It is designed to detect clusters of galaxies over the redshift range 0.1 {approx}< z {approx}< 1. The primary aim is to build a statistically complete, large ({approx}10{sup 4}) sample of clusters, covering a sufficiently long redshift baseline to be able to place constraints on cosmological parameters via the evolution of the cluster mass function. Other main science goals include building a large sample of high surface brightness, strongly gravitationally lensed arcs associated with these clusters, and an unprecedented sample of several tens of thousands of galaxy clusters and groups, spanning a large range of halo mass, with which to study the properties and evolution of their member galaxies. This paper describes the design of the survey and the methodology for acquiring, reducing, and calibrating the data for the production of high-precision photometric catalogs. We describe the method for calibrating our griz imaging data using the colors of the stellar locus and overlapping Two Micron All Sky Survey photometry. This yields an absolute accuracy of <0.03 mag on any color and {approx}0.05 mag in the r-band magnitude, verified with respect to the Sloan Digital Sky Survey (SDSS). Our astrometric calibration is accurate to <<0.''3 from comparison with SDSS positions. RCS-2 reaches average 5{sigma} point-source limiting magnitudes of griz = [24.4, 24.3, 23.7, 22.8], approximately 1-2 mag deeper than the SDSS. Due to the queue-scheduled nature of the observations, the data are highly uniform and taken in excellent seeing, mostly FWHM {approx}< 0.''7 in the r band. In addition to the main science goals just described, these data form the basis for a number of other planned and ongoing projects (including the WiggleZ survey), making RCS-2 an important next-generation imaging survey.

  13. A Survey of Localized Star Clusters in NGC 1427A

    NASA Astrophysics Data System (ADS)

    Weaver, John R.; Gregg, Michael

    2016-01-01

    It is well established that galactic clusters provide dynamic environments in which to examine galaxy evolution. The starbursting dwarf irregular NGC 1427A presents an interesting case as it is being pulled into the nearby Fornax cluster at supersonic speeds, producing a visibly exceptional star formation rate and notably blue colors. It has been suggested that the highly deformed structure of NGC 1427A is due to ram pressure stripping as a result of interacting with a super-heated ICM provided by several nearby elliptical galaxies. The gas density profile of its leading edge is similar to a "bow-shock", containing several dozen super-star clusters (SSCs) and thousands of smaller star forming clusters. It is clearly evident that the properties of NGC 1427A change rapidly over relatively short distances. Using dithered HST/ACS images in Sloan equivalent g' r' i' z' and Hα filters, we present a morphological and photometric study of NGC 1427A using a novel approach in which stellar properties are measured from sources grouped within localized regions. Apertures are fitted for ~5000 sources at 4σ using a filter-combined master image. Four characteristic regions are chosen to study stellar properties, selected interactively through DS9. We then introduce COMET, a specially-designed source catalog handler for producing graphical figures of each region, cropping both spatially and photometrically. These are then batch-reviewed and analyzed using synthetic isochrones corresponding of each region. Hα bright sources are indicated to illustrate the significance of SSCs. Secondary analysis is carried out using smoothed color maps of source-subtracted diffuse light, yielding penetrative mapping of underlying stellar populations. We show for the first time how the dynamical stellar populations of NGC 1427A differ as a function of position across the surface of the galaxy, ultimately furthering our understanding of cluster interactions and the evolution of irregular galaxies

  14. The IMACS Cluster Building Survey. I. Description of the Survey and Analysis Methods

    NASA Technical Reports Server (NTRS)

    Oemler Jr., Augustus; Dressler, Alan; Gladders, Michael G.; Rigby, Jane R.; Bai, Lei; Kelson, Daniel; Villanueva, Edward; Fritz, Jacopo; Rieke, George; Poggianti, Bianca M.; Vulcani, Benedetta

    2013-01-01

    The IMACS Cluster Building Survey uses the wide field spectroscopic capabilities of the IMACS spectrograph on the 6.5 m Baade Telescope to survey the large-scale environment surrounding rich intermediate-redshift clusters of galaxies. The goal is to understand the processes which may be transforming star-forming field galaxies into quiescent cluster members as groups and individual galaxies fall into the cluster from the surrounding supercluster. This first paper describes the survey: the data taking and reduction methods. We provide new calibrations of star formation rates (SFRs) derived from optical and infrared spectroscopy and photometry. We demonstrate that there is a tight relation between the observed SFR per unit B luminosity, and the ratio of the extinctions of the stellar continuum and the optical emission lines.With this, we can obtain accurate extinction-corrected colors of galaxies. Using these colors as well as other spectral measures, we determine new criteria for the existence of ongoing and recent starbursts in galaxies.

  15. The XMM Cluster Survey: The Halo Occupation Number of BOSS galaxies in X-ray clusters

    NASA Astrophysics Data System (ADS)

    Mehrtens, Nicola; Romer, A. Kathy; Nichol, Robert C.; Collins, Chris A.; Sahlén, Martin; Rooney, Philip J.; Mayers, Julian A.; Bermeo-Hernandez, A.; Bristow, Martyn; Capozzi, Diego; Christodoulou, L.; Comparat, Johan; Hilton, Matt; Hoyle, Ben; Kay, Scott T.; Liddle, Andrew R.; Mann, Robert G.; Masters, Karen; Miller, Christopher J.; Parejko, John K.; Prada, Francisco; Ross, Ashley J.; Schneider, Donald P.; Stott, John P.; Streblyanska, Alina; Viana, Pedro T. P.; White, Martin; Wilcox, Harry; Zehavi, Idit

    2016-08-01

    We present a direct measurement of the mean halo occupation distribution (HOD) of galaxies taken from the eleventh data release (DR11) of the Sloan Digital Sky Survey-III Baryon Acoustic Oscillation Survey (BOSS). The HOD of BOSS low-redshift (LOWZ: 0.2 < z < 0.4) and Constant-Mass (CMASS: 0.43 < z < 0.7) galaxies is inferred via their association with the dark-matter halos of 174 X-ray-selected galaxy clusters drawn from the XMM Cluster Survey (XCS). Halo masses are determined for each galaxy cluster based on X-ray temperature measurements, and range between log10(M180/M⊙) = 13 - 15. Our directly-measured HODs are consistent with the HOD-model fits inferred via the galaxy-clustering analyses of Parejko et al. (2013) for the BOSS LOWZ sample and White et al. (2011) for the BOSS CMASS sample. Under the simplifying assumption that the other parameters that describe the HOD hold the values measured by these authors, we have determined a best-fit alpha-index of 0.91±0.08 and 1.27^{+0.03}_{-0.04} for the CMASS and LOWZ HOD, respectively. These alpha-index values are consistent with those measured by White et al. (2011) and Parejko et al. (2013). In summary, our study provides independent support for the HOD-models assumed during the development of the BOSS mock-galaxy catalogues that have subsequently been used to derive BOSS cosmological constraints.

  16. The next generation Virgo cluster survey. VIII. The spatial distribution of globular clusters in the Virgo cluster

    SciTech Connect

    Durrell, Patrick R.; Accetta, Katharine; Côté, Patrick; Blakeslee, John P.; Ferrarese, Laura; McConnachie, Alan; Gwyn, Stephen; Peng, Eric W.; Zhang, Hongxin; Mihos, J. Christopher; Puzia, Thomas H.; Jordán, Andrés; Lançon, Ariane; Liu, Chengze; Cuillandre, Jean-Charles; Boissier, Samuel; Boselli, Alessandro; Courteau, Stéphane; Duc, Pierre-Alain; and others

    2014-10-20

    We report on a large-scale study of the distribution of globular clusters (GCs) throughout the Virgo cluster, based on photometry from the Next Generation Virgo Cluster Survey (NGVS), a large imaging survey covering Virgo's primary subclusters (Virgo A = M87 and Virgo B = M49) out to their virial radii. Using the g{sub o}{sup ′}, (g' – i') {sub o} color-magnitude diagram of unresolved and marginally resolved sources within the NGVS, we have constructed two-dimensional maps of the (irregular) GC distribution over 100 deg{sup 2} to a depth of g{sub o}{sup ′} = 24. We present the clearest evidence to date showing the difference in concentration between red and blue GCs over the full extent of the cluster, where the red (more metal-rich) GCs are largely located around the massive early-type galaxies in Virgo, while the blue (metal-poor) GCs have a much more extended spatial distribution with significant populations still present beyond 83' (∼215 kpc) along the major axes of both M49 and M87. A comparison of our GC maps to the diffuse light in the outermost regions of M49 and M87 show remarkable agreement in the shape, ellipticity, and boxiness of both luminous systems. We also find evidence for spatial enhancements of GCs surrounding M87 that may be indicative of recent interactions or an ongoing merger history. We compare the GC map to that of the locations of Virgo galaxies and the X-ray intracluster gas, and find generally good agreement between these various baryonic structures. We calculate the Virgo cluster contains a total population of N {sub GC} = 67, 300 ± 14, 400, of which 35% are located in M87 and M49 alone. For the first time, we compute a cluster-wide specific frequency S {sub N,} {sub CL} = 2.8 ± 0.7, after correcting for Virgo's diffuse light. We also find a GC-to-baryonic mass fraction ε {sub b} = 5.7 ± 1.1 × 10{sup –4} and a GC-to-total cluster mass formation efficiency ε {sub t} = 2.9 ± 0.5 × 10{sup –5}, the latter values

  17. The ESO Nearby Abell Cluster Survey. II. The distribution of velocity dispersions of rich galaxy clusters.

    NASA Astrophysics Data System (ADS)

    Mazure, A.; Katgert, P.; den Hartog, R.; Biviano, A.; Dubath, P.; Escalera, E.; Focardi, P.; Gerbal, D.; Giuricin, G.; Jones, B.; Le Fevre, O.; Moles, M.; Perea, J.; Rhee, G.

    1996-06-01

    The ESO Nearby Abell Cluster Survey (the ENACS) has yielded 5634 redshifts for galaxies in the directions of 107 rich, Southern clusters selected from the ACO catalogue (Abell et al. 1989). By combining these data with another 1000 redshifts from the literature, of galaxies in 37 clusters, we construct a volume-limited sample of 128 R_ACO_>=1 clusters in a solid angle of 2.55sr centered on the South Galactic Pole, out to a redshift z=0.1. For a subset of 80 of these clusters we can calculate a reliable velocity dispersion, based on at least 10 (but very often between 30 and 150) redshifts. We deal with the main observational problem that hampers an unambiguous interpretation of the distribution of cluster velocity dispersions, namely the contamination by fore- and background galaxies. We also discuss in detail the completeness of the cluster samples for which we derive the distribution of cluster velocity dispersions. We find that a cluster sample which is complete in terms of the field-corrected richness count given in the ACO catalogue gives a result that is essentially identical to that based on a smaller and more conservative sample which is complete in terms of an intrinsic richness count that has been corrected for superposition effects. We find that the large apparent spread in the relation between velocity dispersion and richness count (based either on visual inspection or on machine counts) must be largely intrinsic; i.e. this spread is not primarily due to measurement uncertainties. One of the consequences of the (very) broad relation between cluster richness and velocity dispersion is that all samples of clusters that are defined complete with respect to richness count are unavoidably biased against low-σ_V_ clusters. For the richness limit of our sample this bias operates only for velocity dispersions less than =~800km/sec. We obtain a statistically reliable distribution of global velocity dispersions which, for velocity dispersions σ_V_>800km/s, is

  18. Searching for Variable Sources in the Rapid Temporal Survey

    NASA Astrophysics Data System (ADS)

    Barclay, Thomas

    2012-03-01

    The Rapid Temporal Survey explores the faint, variable sky. I have led the development of the data reduction and analysis pipeline for this survey and have played a leading role in the observation and analysis of follow-up data. The survey and follow-up work is presented in this thesis. The strategy of the survey is to observe fields close to the Galactic plane at a cadence of ~1 min for around two hours down to a depth of g' = 23 The data presented in this thesis cover 31 square degrees of which 16 are within 10^o of the Galactic plane. This is the first dedicated survey to explore this parameter space and such I have had to develop new techniques when dealing with the data. The photometry was performed using a difference imaging technique and resulted in over 3 × 10^6 light curves. This work primarily deals with periodic variability and with this aim I have developed a method which combines two algorithms (Lomb-Scargle and Analysis of Variance) to produce a sub-set of variable sources which contains a very low number of false positives –around 600 out of 1.2 × 10^5 detected variables. For sources brighter than g' = 21 this technique is able to detect – at a confidence above 90 per cent – variability on time-scales of less than 10 min to tens of minutes in source with semi-amplitudes of less than 0.04 mag. Spectroscopic follow-up observations of a number of these targets have been performed and have resulted in the discovery of many different variables from several different classes. I highlight three populations to study in more detail: short-period, variable A-stars; SX Phe and /delta Scuti stars; and pulsating white dwarfs. Of particular interest are the SX Phe stars which I have found to be as far away as 30 kpc from us. I also provide a detailed examination of two variables sources: one is a dwarf nova which was discovered through quasi-periodic oscillations in quiescence, the other a pulsating white dwarf which appears to have a hot companion. I

  19. The Digitized First Byurakan Survey on ArmCluster

    NASA Astrophysics Data System (ADS)

    Mickaelian, A. M.; Astsatryan, H. V.; Sahakyan, V. G.; Sargsyan, L. A.; Nesci, R.; Cirimele, G.; Harutyunian, H. A.; Magakian, T. Yu.; Sinamyan, P. K.; Mikayelyan, G. A.

    2009-10-01

    The Digitized First Byurakan Survey (DFBS) is the digitized version of the famous Markarian Survey, also known as the First Byurakan Survey (FBS). It is the largest low dispersion spectroscopic survey of the sky covering 17,000 square degrees at galactic latitudes |b|>15(o) . DFBS provides the astronomical community with images and extracted spectra for all objects present in the FBS plates. Some 1800 plates have been scanned and stored and programs were developed to compute the astrometric solution, extract the spectra, and apply wavelength and photometric calibration for the objects. The DFBS database and catalog have been assembled containing data for nearly 20,000,000 objects. A classification scheme for the DFBS spectra is being developed. DFBS has been installed on dedicated servers at Univerista di Roma ``La Sapienza" (Italy) and at present on the ArmCluster at the Institute for Informatics and Automation Problems (Armenia). A work is active on making the DFBS available through the Virtual Observatory standards and access to spectroscopic data. From the point of view of VO, the DFBS is a new database needing both image and spectra access tools and an interchange between these two standards. Algorithms, tools, and facilities needed for efficient use of the DFBS are discussed, in particular the spectra extraction, visualization, and analysis tools. New scientific projects as well as existing surveys will benefit by the digitized images and the ready-to-use extracted spectra which will allow an efficient computer-based analysis of the dataset. The Armenian Virtual Observatory (ArVO) is based on the DFBS database and other large-area surveys and catalogue data and is a part of the International Virtual Observatory Alliance (IVOA).

  20. The Herschel Virgo Cluster Survey. XVIII. Star-forming dwarf galaxies in a cluster environment

    NASA Astrophysics Data System (ADS)

    Grossi, M.; Hunt, L. K.; Madden, S. C.; Hughes, T. M.; Auld, R.; Baes, M.; Bendo, G. J.; Bianchi, S.; Bizzocchi, L.; Boquien, M.; Boselli, A.; Clemens, M.; Corbelli, E.; Cortese, L.; Davies, J.; De Looze, I.; di Serego Alighieri, S.; Fritz, J.; Pappalardo, C.; Pierini, D.; Rémy-Ruyer, A.; Smith, M. W. L.; Verstappen, J.; Viaene, S.; Vlahakis, C.

    2015-02-01

    To assess the effects of the cluster environment on the different components of the interstellar medium, we analyse the far-infrared (FIR) and submillimetre (submm) properties of a sample of star-forming dwarf galaxies detected by the Herschel Virgo Cluster Survey (HeViCS). We determine dust masses and dust temperatures by fitting a modified black body function to the spectral energy distributions (SEDs). Stellar and gas masses, star formation rates (SFRs), and metallicities are obtained from the analysis of a set of ancillary data. Dust is detected in 49 out of a total 140 optically identified dwarfs covered by the HeViCS field; considering only dwarfs brighter than mB = 18 mag, this gives a detection rate of 43%. After evaluating different emissivity indices, we find that the FIR-submm SEDs are best-fit by β = 1.5, with a median dust temperature Td = 22.4 K. Assuming β = 1.5, 67% of the 23 galaxies detected in all five Herschel bands show emission at 500 μm in excess of the modified black-body model. The fraction of galaxies with a submillimetre excess decreases for lower values of β, while a similarly high fraction (54%) is found if a β-free SED modelling is applied. The excess is inversely correlated with SFR and stellar masses. To study the variations in the global properties of our sample that come from environmental effects, we compare the Virgo dwarfs to other Herschel surveys,such as the Key Insights into Nearby Galaxies: Far-Infrared Survey with Herschel (KINGFISH), the Dwarf Galaxy Survey (DGS), and the HeViCS Bright Galaxy Catalogue (BGC). We explore the relations between stellar mass and Hi fraction, specific star formation rate, dust fraction, gas-to-dust ratio over a wide range of stellar masses (from 107 to 1011 M⊙) for both dwarfs and spirals. Highly Hi-deficient Virgo dwarf galaxies are mostly characterised by quenched star formation activity and lower dust fractions giving hints for dust stripping in cluster dwarfs. However, to explain the

  1. THE IMACS CLUSTER BUILDING SURVEY. II. SPECTRAL EVOLUTION OF GALAXIES IN THE EPOCH OF CLUSTER ASSEMBLY

    SciTech Connect

    Dressler, Alan; Oemler, Augustus Jr.; Poggianti, Bianca M.; Vulcani, Benedetta; Gladders, Michael D.; Abramson, Louis

    2013-06-10

    The IMACS Cluster Building Survey (ICBS) provides spectra of {approx}2200 galaxies 0.31 < z < 0.54 in five rich clusters (R {approx}< 5 Mpc) and the field. Infalling, dynamically cold groups with tens of members account for approximately half of the supercluster population, contributing to a growth in cluster mass of {approx}100% by the present day. The ICBS spectra distinguish non-star-forming (PAS) and poststarburst (PSB) from star-forming galaxies-continuously star-forming (CSF) or starbursts (SBH or SBO), identified by anomalously strong H{delta} absorption or [O II] emission. For the infalling cluster groups and similar field groups, we find a correlation between PAS+PSB fraction and group mass, indicating substantial ''preprocessing'' through quenching mechanisms that can turn star-forming galaxies into passive galaxies without the unique environment of rich clusters. SBH + SBO starburst galaxies are common, and they maintain an approximately constant ratio (SBH+SBO)/CSF Almost-Equal-To 25% in all environments-from field, to groups, to rich clusters. Similarly, while PSB galaxies strongly favor denser environments, PSB/PAS Almost-Equal-To 10%-20% for all environments. This result, and their timescale {tau} {approx} 500 Myr, indicates that starbursts are not signatures of a quenching mechanism that produces the majority of passive galaxies. We suggest instead that starbursts and poststarbursts signal minor mergers and accretions, in star-forming and passive galaxies, respectively, and that the principal mechanisms for producing passive systems are (1) early major mergers, for elliptical galaxies, and (2) later, less violent processes-such as starvation and tidal stripping, for S0 galaxies.

  2. The swift UVOT stars survey. I. Methods and test clusters

    SciTech Connect

    Siegel, Michael H.; Porterfield, Blair L.; Linevsky, Jacquelyn S.; Bond, Howard E.; Hoversten, Erik A.; Berrier, Joshua L.; Gronwall, Caryl A.; Holland, Stephen T.; Breeveld, Alice A.; Brown, Peter J. E-mail: blp14@psu.edu E-mail: caryl@astro.psu.edu E-mail: aab@mssl.ucl.ac.uk

    2014-12-01

    We describe the motivations and background of a large survey of nearby stellar populations using the Ultraviolet Optical Telescope (UVOT) on board the Swift Gamma-Ray Burst Mission. UVOT, with its wide field, near-UV sensitivity, and 2.″3 spatial resolution, is uniquely suited to studying nearby stellar populations and providing insight into the near-UV properties of hot stars and the contribution of those stars to the integrated light of more distant stellar populations. We review the state of UV stellar photometry, outline the survey, and address problems specific to wide- and crowded-field UVOT photometry. We present color–magnitude diagrams of the nearby open clusters M67, NGC 188, and NGC 2539, and the globular cluster M79. We demonstrate that UVOT can easily discern the young- and intermediate-age main sequences, blue stragglers, and hot white dwarfs, producing results consistent with previous studies. We also find that it characterizes the blue horizontal branch of M79 and easily identifies a known post-asymptotic giant branch star.

  3. A New Galaxy Cluster Survey For The Northern Sky

    NASA Astrophysics Data System (ADS)

    Gal, R. R.; et al.

    We present a new galaxy cluster catalog constructed from the Digitized Second Palomar Observatory Sky Survey. Our objectively defined catalog covers the entire Northern sky at |b|>30°, and contains nearly 20,000 cluster candidates with photometric redshifts and richnesses. Extensive simulations are used to establish contamination rates and our selection function. We also present some initial work on cluster mass estimation directly from our plate photometry. bibitem Borgani, S., Girardi, M., Carlberg, R. G., Yee, H. K. C., & Ellingson, E. 1999, apj, 527, 561 bibitem Djorgovski, S. G., Odewahn, S. C., Gal, R. R., Brunner, R., de Carvalho, R. R., Longo, G. & Scaramella, R. 1999, American Astronomical Society Meeting, 194, 0414 bibitem Gal, R. R., de Carvalho, R. R., Odewahn, S. C., Djorgovski, S. G., Mahabal, A., Brunner, R. J. & Lopes, P. 2003, AJ, in press bibitem Kim, R. S. J. 2001, Ph.D. Thesis, Princeton bibitem Paolillo, M., Andreon, S., Longo, G., Puddu, E., Gal, R. R., Scaramella, R., Djorgovski, S. G., & de Carvalho, R. 2001, aa, 367, 59 bibitem Postman, M., Lauer, T. R., Oegerle, W., & Donahue, M. 2002, apj, 579, 93 bibitem Struble, M. F. & Rood, H. J. 1999, apjs, 125, 35

  4. The OCCASO Survey: Open Clusters Chemical Abundances from Spanish Observatories

    NASA Astrophysics Data System (ADS)

    Casamiquela, L.; Carrera, R.; Jordi, C.; Balaguer-Núñez, L.

    2014-07-01

    Stellar clusters are crucial in the study of a variety of topics including the star formation process, stellar nucleosynthesis and evolution, dynamical interaction among stars, or the assembly and evolution of galaxies. In particular, Open Clusters (OCs) have been widely used to constrain the formation and evolution of the Milky Way disc. They provide information about the chemical patterns and the existence of radial and vertical gradients or an age-metallicity relation. However, all these investigations are hampered by the fact that only a small fraction of clusters have been studied homogeneously. Galactic surveys performed from the ground such as the Apache Point Observatory Galactic Evolution Experiment (APOGEE), the Gaia-ESO Survey (GES), or the GALactic Archaeology with HERMES (GALAH) include OCs among their targets. OCs are also sampled from the space by the Gaia and Kepler missions. The OCCASO goal is to derive abundances for more than 20 chemical species in at least 6 Red Clump stars in ˜30 Northern hemisphere OCs. In order to ensure the reliability of the derived chemical abundances, these are derived using different analysis techniques similar to what is being performed by GES. One of the OCCASO requirements is the homogeneity between instruments, methods and model atmospheres used, and in the same scale than the GES-UVES abundances. For this reason we are performing different tests checking internal and external consistency. Derived stellar atmosphere parameters and Fe abundances will be published in the first data release scheduled for the first semester of 2015. The online pdf of the poster with first results is available at https://gaia.ub.edu/Twiki/pub/GREATITNFC/ProgramFinalconference/poster_OCCASO.pdf.

  5. A faint galaxy redshift survey behind massive clusters

    SciTech Connect

    Frye, Brenda

    1999-12-01

    This thesis is concerned with the gravitational lensing effect by massive galaxy clusters. We have explored a new technique for measuring galaxy masses and for detecting high-z galaxies by their optical colors. A redshift survey has been obtained at the Keck for a magnitude limited sample of objects (I<23) behind three clusters, A1689, A2390, and A2218 within a radius of 0.5M pc. For each cluster we see both a clear trend of increasing flux and redshift towards the center. This behavior is the result of image magnifications, such that at fixed redshift one sees further down the luminosity function. The gradient of this magnification is, unlike measurements of image distortion, sensitive to the mass profile, and found to depart strongly from a pure isothermal halo. We have found that V RI color selection can be used effectively as a discriminant for finding high-z galaxies behind clusters and present five 4.1 < z < 5.1 spectra which are of very high quality due to their high mean magnification of {approximately}20, showing strong, visibly-saturated interstellar metal lines in some cases. We have also investigated the radio ring lens PKS 1830-211, locating the source and multiple images and detected molecular absorption at mm wavelengths. Broad molecular absorption of width 1/40kms is found toward the southwest component only, where surprisingly it does not reach the base of the continuum, which implies incomplete coverage of the SW component by molecular gas, despite the small projected size of the source, less than 1/8h pc at the absorption redshift.

  6. Searching for massive clusters in weak lensing surveys

    NASA Astrophysics Data System (ADS)

    Hamana, Takashi; Takada, Masahiro; Yoshida, Naoki

    2004-05-01

    We explore the ability of weak lensing surveys to locate massive clusters. We use both analytic models of dark matter haloes and mock weak lensing surveys generated from a large cosmological N-body simulation. The analytic models describe the average properties of weak lensing haloes and predict the number counts, enabling us to compute an effective survey selection function. We argue that the detectability of massive haloes depends not only on the halo mass but also strongly on the redshift where the halo is located. We test the model prediction for the peak number counts in weak lensing mass maps against mock numerical data, and find that the noise resulting from intrinsic galaxy ellipticities causes a systematic effect which increases the peak counts. We develop a correction scheme for the systematic effect in an empirical manner, and show that, after correction, the model prediction agrees well with the mock data. The mock data is also used to examine the completeness and efficiency of the weak lensing halo search by fully taking into account the noise and the projection effect by large-scale structures. We show that the detection threshold of S/N = 4 ~ 5 gives an optimal balance between completeness and efficiency. Our results suggest that, for a weak lensing survey with a galaxy number density of ng= 30 arcmin-2 with a mean redshift of z= 1, the mean number of haloes which are expected to cause lensing signals above S/N = 4 is Nhalo(S/N > 4) = 37 per 10 deg2, whereas 23 of the haloes are actually detected with S/N > 4, giving the effective completeness as good as 63 per cent. Alternatively, the mean number of peaks in the same area is Npeak= 62 for a detection threshold of S/N = 4. Among the 62 peaks, 23 are caused by haloes with the expected peak height S/N > 4, 13 result from haloes with 3 < S/N < 4 and the remaining 26 peaks are either the false peaks caused by the noise or haloes with a lower expected peak height. Therefore the contamination rate is 44

  7. Diffuse Extreme-Ultraviolet Emission from the Coma Cluster: Evidence for Rapidly Cooling Gases at Submegakelvin Temperatures

    PubMed

    Lieu; Mittaz; Bowyer; Breen; Lockman; Murphy; Hwang

    1996-11-22

    The central region of the Coma cluster of galaxies was observed in the energy band from 0.065 to 0.245 kiloelectron volts by the Deep Survey telescope aboard the Extreme Ultraviolet Explorer. A diffuse emission halo of angular diameter approximately 30 arc minutes was detected. The extreme-ultraviolet (EUV) emission level exceeds that expected from the x-ray temperature gas in Coma. This halo suggests the presence of two more phases in the emitting gas, one at a temperature of approximately 2 x 10(6) kelvin and the other at approximately 8 x 10(5) kelvin. The latter phase cools rapidly and, in steady state, would have produced cold matter with a mass of approximately 10(14) solar masses within the EUV halo. Although a similar EUV enhancement was discovered in the Virgo cluster, this detection in Coma applies to a noncooling flow system. PMID:8910264

  8. Extragalactic jets as probes of distant clusters of galaxies and the clusters occupied by bent radio AGN (COBRA) survey

    NASA Astrophysics Data System (ADS)

    Blanton, Elizabeth L.; Paterno-Mahler, Rachel; Wing, Joshua D.; Ashby, M. L. N.; Golden-Marx, Emmet; Brodwin, Mark; Douglass, E. M.; Randall, Scott W.; Clarke, T. E.

    2015-03-01

    We are conducting a large survey of distant clusters of galaxies using radio sources with bent jets and lobes as tracers. These radio sources are driven by AGN and achieve their bent morphologies through interaction with the surrounding gas found in clusters of galaxies. Based on low-redshift studies, these types of sources can be used to identify clusters very efficiently. We present initial results from our survey of 653 bent-double radio sources with optical hosts too faint to appear in the SDSS. The sample was observed in the infrared with Spitzer, and it has revealed ~200 distant clusters or proto-clusters in the redshift range z ~ 0.7 - 3.0. The sample of bent-doubles contains both quasars and radio galaxies enabling us to study both radiative and kinetic mode feedback in cluster and group environments at a wide range of redshifts.

  9. The Next Generation Virgo Cluster Survey. IV. NGC 4216: A Bombarded Spiral in the Virgo Cluster

    NASA Astrophysics Data System (ADS)

    Paudel, Sanjaya; Duc, Pierre-Alain; Côté, Patrick; Cuillandre, Jean-Charles; Ferrarese, Laura; Ferriere, Etienne; Gwyn, Stephen D. J.; Mihos, J. Christopher; Vollmer, Bernd; Balogh, Michael L.; Carlberg, Ray G.; Boissier, Samuel; Boselli, Alessandro; Durrell, Patrick R.; Emsellem, Eric; MacArthur, Lauren A.; Mei, Simona; Michel-Dansac, Leo; van Driel, Wim

    2013-04-01

    The final stages of mass assembly of present-day massive galaxies are expected to occur through the accretion of multiple satellites. Cosmological simulations thus predict a high frequency of stellar streams resulting from this mass accretion around the massive galaxies in the Local Volume. Such tidal streams are difficult to observe, especially in dense cluster environments, where they are readily destroyed. We present an investigation into the origins of a series of interlaced narrow filamentary stellar structures, loops and plumes in the vicinity of the Virgo Cluster, edge-on spiral galaxy, NGC 4216 that were previously identified by the Blackbird telescope. Using the deeper, higher-resolution, and precisely calibrated optical CFHT/MegaCam images obtained as part of the Next Generation Virgo Cluster Survey (NGVS), we confirm the previously identified features and identify a few additional structures. The NGVS data allowed us to make a physical study of these low surface brightness features and investigate their origin. The likely progenitors of the structures were identified as either already cataloged Virgo Cluster Catalog dwarfs or newly discovered satellites caught in the act of being destroyed. They have the same g - i color index and likely contain similar stellar populations. The alignment of three dwarfs along an apparently single stream is intriguing, and we cannot totally exclude that these are second-generation dwarf galaxies being born inside the filament from the debris of an original dwarf. The observed complex structures, including in particular a stream apparently emanating from a satellite of a satellite, point to a high rate of ongoing dwarf destruction/accretion in the region of the Virgo Cluster where NGC 4216 is located. We discuss the age of the interactions and whether they occurred in a group that is just falling into the cluster and shows signs of the so-called pre-processing before it gets affected by the cluster environment, or in a

  10. Galaxy clustering with photometric surveys using PDF redshift information

    DOE PAGESBeta

    Asorey, J.; Carrasco Kind, M.; Sevilla-Noarbe, I.; Brunner, R. J.; Thaler, J.

    2016-03-28

    Here, photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colors, that are obtained through multi-band imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths aremore » $$\\Delta z=0.1$$, the use of the entire PDF reduces the typical measurement bias from 5%, when using single point estimates, to 3%.« less

  11. Galaxy clustering with photometric surveys using PDF redshift information

    NASA Astrophysics Data System (ADS)

    Asorey, J.; Carrasco Kind, M.; Sevilla-Noarbe, I.; Brunner, R. J.; Thaler, J.

    2016-06-01

    Photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colours, that are obtained through multiband imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths are Δz = 0.1, the use of the entire PDF reduces the typical measurement bias from 5 per cent, when using single point estimates, to 3 per cent.

  12. The Role of Environment in Shaping Galaxy Evolution at High Redshift: Insights from the SpARCS Cluster Survey

    NASA Astrophysics Data System (ADS)

    Wilson, Gillian

    2015-08-01

    Between z = 2 and z = 1, the main progenitors of present-day massive clusters undergo rapid collapse, and cluster members transform from active star-forming to quiescent galaxies. The SpARCS survey is one of the largest surveys designed to detect clusters of galaxies at z> 1, and has discovered hundreds of Spitzer IR-selected clusters.I will present results from GCLASS, a 25-night Gemini/GMOS spectroscopic follow-up survey of ten of the most massive SpARCS clusters at z~1, and explain what we are learning about quenching and stellar mass assembly of galaxies in these, the densest of environments, relative to the field population. I will explain how predictions and observations of the stellar mass growth of Brightest Cluster Galaxies, previously controversially divergent, are now coming into agreement, and discuss the evidence for the relative importance of mergers versus in-situ star formation in driving this stellar mass growth as a function of redshift.I will also present a sample of newly-confirmed clusters at z~2 for which we have HST spectroscopy and imaging, and have been targeting with Keck/MOSFIRE. I will conclude by discussing GOGREEN and DEEPDRILL, two new large surveys approved by Gemini & Spitzer, designed to study the effects of environment at lower stellar mass and at higher redshift, respectively. Collectively, these powerful new surveys are beginning to allow us to place constraints on the location and timescale of quenching and, in concert with both hydro-simulations and semi-analytic models, identify the complex role of environment in shaping galaxy evolution over cosmic time.

  13. The Herschel Virgo Cluster Survey . VII. Dust in cluster dwarf elliptical galaxies

    NASA Astrophysics Data System (ADS)

    De Looze, I.; Baes, M.; Zibetti, S.; Fritz, J.; Cortese, L.; Davies, J. I.; Verstappen, J.; Bendo, G. J.; Bianchi, S.; Clemens, M.; Bomans, D. J.; Boselli, A.; Corbelli, E.; Dariush, A.; di Serego Alighieri, S.; Fadda, D.; Garcia-Appadoo, D. A.; Gavazzi, G.; Giovanardi, C.; Grossi, M.; Hughes, T. M.; Hunt, L. K.; Jones, A. P.; Madden, S.; Pierini, D.; Pohlen, M.; Sabatini, S.; Smith, M. W. L.; Vlahakis, C.; Xilouris, E. M.

    2010-07-01

    We use the science demonstration phase data of the Herschel Virgo Cluster Survey to search for dust emission of early-type dwarf galaxies in the central regions of the Virgo cluster as an alternative way of identifying the interstellar medium. We present the first possible far-infrared detection of cluster early-type dwarf galaxies: VCC 781 and VCC 951 are detected at the 10σ level in the SPIRE 250 μm image. Both detected galaxies have dust masses of the order of 105 M_⊙ and average dust temperatures ≈20 K. The detection rate (less than 1%) is quite high compared to the 1.7% detection rate for Hi emission, considering that dwarfs in the central regions are more Hi deficient. We conclude that the removal of interstellar dust from dwarf galaxies resulting from ram pressure stripping, harassment, or tidal effects must be as efficient as the removal of interstellar gas. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  14. The ATCA Survey for Black Holes in Southern Globular Clusters

    NASA Astrophysics Data System (ADS)

    Strader, Jay; Miller-Jones, James; Maccarone, Tom; Chomiuk, Laura

    2013-10-01

    Hundreds of stellar-mass black holes (BHs) are expected to form in the early lives of most globular star clusters (GCs), mass segregate to the cluster center, and largely be ejected through mutual gravitational interactions. Observations by our group have provided the first strong evidence for stellar-mass BHs in Galactic GCs. The key advance has been the use of radio continuum observations sensitive to BHs with low mass accretion rates. The existence of stellar-mass BHs in GCs would have broad implications: (i) GCs would become important hunting grounds for stellar-mass BHs; (ii) BHs in GCs would offer tests of the physics of low-luminosity accretion; (iii) GCs might offer a less biased view of the BH mass function than the field; and (iv) the prospects for detecting gravitational wave sources such as BH--BH or BH--pulsar binaries would be improved. The same radio observations can also reveal the presence of intermediate-mass black holes (IMBHs) in the centers of GCs. The dynamical evidence for IMBHs is hard to interpret uniquely; IMBHs should also be detectable through accretion. Our radio observations have placed the strongest limits to date on the presence of IMBHs in several Galactic GCs. We have begun a deep, systematic radio continuum survey for BHs in Galactic GCs. Here we propose ATCA data for a pilot sample of five southern GCs. With well-defined selection criteria, our sample will allow the first statistical determination of the presence of BHs in GCs.

  15. The XMM Cluster Survey: optical analysis methodology and the first data release

    NASA Astrophysics Data System (ADS)

    Mehrtens, Nicola; Romer, A. Kathy; Hilton, Matt; Lloyd-Davies, E. J.; Miller, Christopher J.; Stanford, S. A.; Hosmer, Mark; Hoyle, Ben; Collins, Chris A.; Liddle, Andrew R.; Viana, Pedro T. P.; Nichol, Robert C.; Stott, John P.; Dubois, E. Naomi; Kay, Scott T.; Sahlén, Martin; Young, Owain; Short, C. J.; Christodoulou, L.; Watson, William A.; Davidson, Michael; Harrison, Craig D.; Baruah, Leon; Smith, Mathew; Burke, Claire; Mayers, Julian A.; Deadman, Paul-James; Rooney, Philip J.; Edmondson, Edward M.; West, Michael; Campbell, Heather C.; Edge, Alastair C.; Mann, Robert G.; Sabirli, Kivanc; Wake, David; Benoist, Christophe; da Costa, Luiz; Maia, Marcio A. G.; Ogando, Ricardo

    2012-06-01

    The XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters using all publicly available data in the XMM-Newton Science Archive. Its main aims are to measure cosmological parameters and trace the evolution of X-ray scaling relations. In this paper we present the first data release from the XMM Cluster Survey (XCS-DR1). This consists of 503 optically confirmed, serendipitously detected, X-ray clusters. Of these clusters, 256 are new to the literature and 357 are new X-ray discoveries. We present 463 clusters with a redshift estimate (0.06 < z < 1.46), including 261 clusters with spectroscopic redshifts. The remainder have photometric redshifts. In addition, we have measured X-ray temperatures (TX) for 401 clusters (0.4 < TX < 14.7 keV). We highlight seven interesting subsamples of XCS-DR1 clusters: (i) 10 clusters at high redshift (z > 1.0, including a new spectroscopically confirmed cluster at z= 1.01); (ii) 66 clusters with high TX (>5 keV) (iii) 130 clusters/groups with low TX (<2 keV) (iv) 27 clusters with measured TX values in the Sloan Digital Sky Survey (SDSS) ‘Stripe 82’ co-add region; (v) 77 clusters with measured TX values in the Dark Energy Survey region; (vi) 40 clusters detected with sufficient counts to permit mass measurements (under the assumption of hydrostatic equilibrium); (vii) 104 clusters that can be used for applications such as the derivation of cosmological parameters and the measurement of cluster scaling relations. The X-ray analysis methodology used to construct and analyse the XCS-DR1 cluster sample has been presented in a companion paper, Lloyd-Davies et al.

  16. Massive open star clusters using the VVV survey. II. Discovery of six clusters with Wolf-Rayet stars

    NASA Astrophysics Data System (ADS)

    Chené, A.-N.; Borissova, J.; Bonatto, C.; Majaess, D. J.; Baume, G.; Clarke, J. R. A.; Kurtev, R.; Schnurr, O.; Bouret, J.-C.; Catelan, M.; Emerson, J. P.; Feinstein, C.; Geisler, D.; de Grijs, R.; Hervé, A.; Ivanov, V. D.; Kumar, M. S. N.; Lucas, P.; Mahy, L.; Martins, F.; Mauro, F.; Minniti, D.; Moni Bidin, C.

    2013-01-01

    Context. The ESO Public Survey "VISTA Variables in the Vía Láctea" (VVV) provides deep multi-epoch infrared observations for an unprecedented 562 sq. degrees of the Galactic bulge, and adjacent regions of the disk. Nearly 150 new open clusters and cluster candidates have been discovered in this survey. Aims: This is the second in a series of papers about young, massive open clusters observed using the VVV survey. We present the first study of six recently discovered clusters. These clusters contain at least one newly discovered Wolf-Rayet (WR) star. Methods: Following the methodology presented in the first paper of the series, wide-field, deep JHKs VVV observations, combined with new infrared spectroscopy, are employed to constrain fundamental parameters for a subset of clusters. Results: We find that the six studied stellar groups are real young (2-7 Myr) and massive (between 0.8 and 2.2 × 103 M⊙) clusters. They are highly obscured (AV ~ 5-24 mag) and compact (1-2 pc). In addition to WR stars, two of the six clusters also contain at least one red supergiant star, and one of these two clusters also contains a blue supergiant. We claim the discovery of 8 new WR stars, and 3 stars showing WR-like emission lines which could be classified WR or OIf. Preliminary analysis provides initial masses of ~30-50 M⊙ for the WR stars. Finally, we discuss the spiral structure of the Galaxy using the six new clusters as tracers, together with the previously studied VVV clusters. Based on observations with ISAAC, VLT, ESO (programme 087.D-0341A), New Technology Telescope at ESO's La Silla Observatory (programme 087.D-0490A) and with the Clay telescope at the Las Campanas Observatory (programme CN2011A-086). Also based on data from the VVV survey (programme 172.B-2002).

  17. Rapid Degradation of the Tetrameric Mn Cluster in Illuminated, PsbO-Depleted Photosystem II Preparations

    SciTech Connect

    Semin, B. K.; Davletshina, L. N.; Ivanov, I. I.; Seibert, M.; Rubin, A. B.

    2012-01-01

    A 'decoupling effect' (light-induced electron transport without O{sub 2} evolution) was observed in Ca-depleted photosystem II (PSII(-Ca)) membranes, which lack PsbP and PsbQ (Semin et al. (2008) Photosynth. Res., 98, 235-249). Here PsbO-depleted PSII (PSII(-PsbO)) membranes (which also lack PsbP and PsbQ) were used to examine effects of PsbO on the decoupling. PSII(-PsbO) membranes do not reduce the acceptor 2,6-dichlorophenolindophenol (DCIP), in contrast to PSII(-Ca) membranes. To understand why DCIP reduction is lost, we studied light effects on the Mn content of PSII(-PsbO) samples and found that when they are first illuminated, Mn cations are rapidly released from the Mn cluster. Addition of an electron acceptor to PSII(-PsbO) samples accelerates the process. No effect of light was found on the Mn cluster in PSII(-Ca) membranes. Our results demonstrate that: (a) the oxidant, which directly oxidizes an as yet undefined substrate in PSII(-Ca) membranes, is the Mn cluster (not the Y{sub Z} radical or P680{sup +}); (b) light causes rapid release of Mn cations from the Mn cluster in PSII(-PsbO) membranes, and the mechanism is discussed; and (c) rapid degradation of the Mn cluster under illumination is significant for understanding the lack of functional activity in some PSII(-PsbO) samples reported by others.

  18. Investigating Faculty Familiarity with Assessment Terminology by Applying Cluster Analysis to Interpret Survey Data

    ERIC Educational Resources Information Center

    Raker, Jeffrey R.; Holme, Thomas A.

    2014-01-01

    A cluster analysis was conducted with a set of survey data on chemistry faculty familiarity with 13 assessment terms. Cluster groupings suggest a high, middle, and low overall familiarity with the terminology and an independent high and low familiarity with terms related to fundamental statistics. The six resultant clusters were found to be…

  19. An X-Ray Survey of the Open Cluster NGC 6475 (M7) with ROSAT

    NASA Technical Reports Server (NTRS)

    Prosser, Charles F.; Stauffer, John R.; Caillault, J.-P.; Balachandran, Suchitra; Stern, Robert A.; Randich, Sofia

    1995-01-01

    A ROSAT x-ray survey, with complimentary optical photometry, of the open cluster NGC 6475 has enabled the detection of approx. 50 late-F to K0 and approx. 70 K/M dwarf new candidate members, providing the first reliable detection of low-mass stars in this low. galactic latitude, 220 Myr old cluster. The x-ray observations reported here have a typical limiting sensitivity of L(sub x) approx. equal to 10(exp 29) erg/s. The detection frequency of early type cluster members is consistent with the hypothesis that the x-ray emitting early type stars are binary systems with an unseen, low-mass secondary producing the x rays. The ratio between x-ray and bolometric luminosity among NGC 6475 members saturates at a spectral-type/color which is intermediate between that in much younger and in much older clusters, consistent with rotational spindown of solar-type stars upon their arrival on the ZAMS. The upper envelope of x-ray luminosity as a function of spectral type is comparable to that of the Pleiades, with the observed spread in x-ray luminosity among low-mass members being likely due to the presence of binaries and relatively rapid rotators. However, the list of x-ray selected candidate members is likely biased against low-mass, slowly rotating single stars. While some preliminary spectroscopic information is given in an appendix, further spectroscopic observations of the new candidate members will aid in interpreting the coronal activity among solar-type NGC 6475 members and their relation to similar stars in older and younger open clusters.

  20. IS THE TWO MICRON ALL SKY SURVEY CLUSTERING DIPOLE CONVERGENT?

    SciTech Connect

    Bilicki, Maciej; Chodorowski, Michal; Jarrett, Thomas; Mamon, Gary A.

    2011-11-01

    There is a long-standing controversy about the convergence of the dipole moment of the galaxy angular distribution (the so-called clustering dipole). Is the dipole convergent at all, and if so, what is the scale of the convergence? We study the growth of the clustering dipole of galaxies as a function of the limiting flux of the sample from the Two Micron All Sky Survey (2MASS). Contrary to some earlier claims, we find that the dipole does not converge before the completeness limit of the 2MASS Extended Source Catalog, i.e., up to 13.5 mag in the near-infrared K{sub s} band (equivalent to an effective distance of 300 Mpc h{sup -1}). We compare the observed growth of the dipole with the theoretically expected, conditional one (i.e., given the velocity of the Local Group relative to the cosmic microwave background), for the {Lambda}CDM power spectrum and cosmological parameters constrained by the Wilkinson Microwave Anisotropy Probe. The observed growth turns out to be within 1{sigma} confidence level of its theoretical counterpart once the proper observational window of the 2MASS flux-limited catalog is included. For a contrast, if the adopted window is a top hat, then the predicted dipole grows significantly faster and converges (within the errors) to its final value for a distance of about 300 Mpc h{sup -1}. By comparing the observational windows, we show that for a given flux limit and a corresponding distance limit, the 2MASS flux-weighted window passes less large-scale signal than the top-hat one. We conclude that the growth of the 2MASS dipole for effective distances greater than 200 Mpc h{sup -1} is only apparent. On the other hand, for a distance of 80 Mpc h{sup -1} (mean depth of the 2MASS Redshift Survey) and the {Lambda}CDM power spectrum, the true dipole is expected to reach only {approx}80% of its final value. Eventually, since for the window function of 2MASS the predicted growth is consistent with the observed one, we can compare the two to evaluate

  1. The High-Redshift Clusters Occupied by Bent Radio AGN (COBRA) Survey

    NASA Astrophysics Data System (ADS)

    Paterno-Mahler, Rachel; Blanton, Elizabeth L.; Wing, Joshua; Ashby, M. L. N.; Brodwin, Mark; Golden-Marx, Emmet

    2015-08-01

    The number of confirmed, high-redshift galaxy clusters is very low compared to the number of well-studied clusters nearby. Bent, double-lobed radio sources are frequently found in galaxy clusters, and thus can be used as tracers for efficiently locating high-redshift clusters. Using our Spitzer Snapshot Survey, we have identified approximately 300 potential new clusters with redshifts 0.7Cluster Occupied by Bent Radio AGN (COBRA) survey. We have created color-magnitude diagrams using infrared and optical data. Using the colors of the radio source host and the red sequence we can estimate redshifts for our clusters, as well as examine the evolution of the cluster galaxies over a large range of cosmic time.

  2. PHAT STELLAR CLUSTER SURVEY. I. YEAR 1 CATALOG AND INTEGRATED PHOTOMETRY

    SciTech Connect

    Johnson, L. Clifton; Dalcanton, Julianne J.; Fouesneau, Morgan; Hodge, Paul W.; Weisz, Daniel R.; Williams, Benjamin F.; Beerman, Lori C.; Seth, Anil C.; Caldwell, Nelson; Gouliermis, Dimitrios A.; Larsen, Soren S.; Olsen, Knut A. G.; San Roman, Izaskun; Sarajedini, Ata; Bianchi, Luciana; Dolphin, Andrew E.; Girardi, Leo; Guhathakurta, Puragra; Lang, Dustin; and others

    2012-06-20

    The Panchromatic Hubble Andromeda Treasury (PHAT) survey is an ongoing Hubble Space Telescope (HST) multi-cycle program to obtain high spatial resolution imaging of one-third of the M31 disk at ultraviolet through near-infrared wavelengths. In this paper, we present the first installment of the PHAT stellar cluster catalog. When completed, the PHAT cluster catalog will be among the largest and most comprehensive surveys of resolved star clusters in any galaxy. The exquisite spatial resolution achieved with HST has allowed us to identify hundreds of new clusters that were previously inaccessible with existing ground-based surveys. We identify 601 clusters in the Year 1 sample, representing more than a factor of four increase over previous catalogs within the current survey area (390 arcmin{sup 2}). This work presents results derived from the first {approx}25% of the survey data; we estimate that the final sample will include {approx}2500 clusters. For the Year 1 objects, we present a catalog with positions, radii, and six-band integrated photometry. Along with a general characterization of the cluster luminosities and colors, we discuss the cluster luminosity function, the cluster size distributions, and highlight a number of individually interesting clusters found in the Year 1 search.

  3. Reducing systematic error in weak lensing cluster surveys

    SciTech Connect

    Utsumi, Yousuke; Miyazaki, Satoshi; Hamana, Takashi; Geller, Margaret J.; Kurtz, Michael J.; Fabricant, Daniel G.; Dell'Antonio, Ian P.; Oguri, Masamune

    2014-05-10

    Weak lensing provides an important route toward collecting samples of clusters of galaxies selected by mass. Subtle systematic errors in image reduction can compromise the power of this technique. We use the B-mode signal to quantify this systematic error and to test methods for reducing this error. We show that two procedures are efficient in suppressing systematic error in the B-mode: (1) refinement of the mosaic CCD warping procedure to conform to absolute celestial coordinates and (2) truncation of the smoothing procedure on a scale of 10'. Application of these procedures reduces the systematic error to 20% of its original amplitude. We provide an analytic expression for the distribution of the highest peaks in noise maps that can be used to estimate the fraction of false peaks in the weak-lensing κ-signal-to-noise ratio (S/N) maps as a function of the detection threshold. Based on this analysis, we select a threshold S/N = 4.56 for identifying an uncontaminated set of weak-lensing peaks in two test fields covering a total area of ∼3 deg{sup 2}. Taken together these fields contain seven peaks above the threshold. Among these, six are probable systems of galaxies and one is a superposition. We confirm the reliability of these peaks with dense redshift surveys, X-ray, and imaging observations. The systematic error reduction procedures we apply are general and can be applied to future large-area weak-lensing surveys. Our high-peak analysis suggests that with an S/N threshold of 4.5, there should be only 2.7 spurious weak-lensing peaks even in an area of 1000 deg{sup 2}, where we expect ∼2000 peaks based on our Subaru fields.

  4. The CfA-Rosat Survey of Distant Clusters of Galaxies

    NASA Technical Reports Server (NTRS)

    McNamara, Brian

    1998-01-01

    We (Vikhlinin, McNamara, Forman, Jones, Hornstrup, Quintana) have completed a new survey of distant clusters of galaxies, which we use to to study cluster evolution over cosmological timescales. The clusters were identified as extended X-ray sources in 650 ROSAT PSPC images of high Galactic latitude fields. Our catalog of approximately 230 extended X-ray sources covers 160 square degrees on the sky. Ours is the largest of the several ROSAT serendipitous cluster surveys in progress (e.g. SHARC, Rosati, WARPS etc.). Using V,R,I imagery obtained at several observatories, we find that greater than 90% of the X-ray sources are associated with distant clusters of galaxies. We have obtained spectroscopic redshifts for nearly 80 clusters in our catalog, and we have measured photometric redshifts for the remaining clusters. Our sample contains more than 20 clusters at z > 0.5. I will discuss the logN-logS relationship for our clusters. Because our large survey area, we are able to confirm the evolution of the most luminous distant clusters first seen in the Einstein Extended Medium Sensitivity Survey. In addition, I will discuss the relationships between optical richness, core radius, and X-ray luminosity for distant, X-ray-selected clusters.

  5. Rapid surveys for program evaluation: design and implementation of an experiment in Ecuador.

    PubMed

    Macintyre, K; Bilsborrow, R E; Olmedo, C; Carrasco, R

    1999-09-01

    This paper presents details from the field test of two rapid surveys in Ecuador in 1995. It focuses on how the surveys were designed and implemented, including descriptions of the sampling procedures, the preparation and use of preprogrammed palmtop computers for data entry, the selection criteria for the interviewing team, and how the training was designed. Lessons are drawn that will assist health professionals plan and carry out better rapid data collection in the future. The objective of the study was to evaluate the reliability and validity of data gathered during the rapid surveys as compared with a recent "gold standard" national survey. A two-way factorial design was used to control for differences in sampling (probability versus quasi-probability) and methods of data collection (paper versus palmtop computer). Few differences were detected between the surveys done on palmtops as compared to paper ones, but urban and rural differentials in contraceptive use were less pronounced in the rapid surveys than in the earlier, national survey. This suggests that caution should be exercised in interpreting the disaggregated data in these rapid surveys. In-depth interviews revealed two features of the rapid surveys that were especially popular: the palmtops for their speed of data entry, and the short questionnaire for its "low impact" on a respondent's time. The common belief that computers would disturb respondents was not found to be the case. Even with no computer experience, the interviewers rapidly mastered the new technology. PMID:10517097

  6. Clustering and meso-level variables in cross-sectional surveys: an example of food aid during the Bosnian crisis

    PubMed Central

    2011-01-01

    Background Focus groups, rapid assessment procedures, key informant interviews and institutional reviews of local health services provide valuable insights on health service resources and performance. A long-standing challenge of health planning is to combine this sort of qualitative evidence in a unified analysis with quantitative evidence from household surveys. A particular challenge in this regard is to take account of the neighbourhood or clustering effects, recognising that these can be informative or incidental. Methods An example of food aid and food sufficiency from the Bosnian emergency (1995-96) illustrates two Lamothe cluster-adjustments of the Mantel Haenszel (MH) procedure, one assuming a fixed odds ratio and the other allowing for informative clustering by not assuming a fixed odds ratio. We compared these with conventional generalised estimating equations and a generalised linear mixed (GLMM) model, using a Laplace adjustment. Results The MH adjustment assuming incidental clustering generated a final model very similar to GEE. The adjustment that does not assume a fixed odds ratio produced a final multivariate model and effect sizes very similar to GLMM. Discussion In medium or large data sets with stratified last stage random sampling, the cluster adjusted MH is substantially more conservative than the naïve MH computation. In the example of food aid in the Bosnian crisis, the cluster adjusted MH that does not assume a fixed odds ratio produced similar results to the GLMM, which identified informative clustering. PMID:22376353

  7. THE EVOLUTION OF DUSTY STAR FORMATION IN GALAXY CLUSTERS TO z = 1: SPITZER INFRARED OBSERVATIONS OF THE FIRST RED-SEQUENCE CLUSTER SURVEY

    SciTech Connect

    Webb, T. M. A.; O'Donnell, D.; Coppin, Kristen; Faloon, Ashley; Geach, James E.; Noble, Allison; Yee, H. K. C.; Gilbank, David; Ellingson, Erica; Gladders, Mike; Muzzin, Adam; Wilson, Gillian; Yan, Renbin

    2013-10-01

    We present the results of an infrared (IR) study of high-redshift galaxy clusters with the MIPS camera on board the Spitzer Space Telescope. We have assembled a sample of 42 clusters from the Red-Sequence Cluster Survey-1 over the redshift range 0.3 < z < 1.0 and spanning an approximate range in mass of 10{sup 14-15} M {sub ☉}. We statistically measure the number of IR-luminous galaxies in clusters above a fixed inferred IR luminosity of 2 × 10{sup 11} M {sub ☉}, assuming a star forming galaxy template, per unit cluster mass and find it increases to higher redshift. Fitting a simple power-law we measure evolution of (1 + z){sup 5.1±1.9} over the range 0.3 < z < 1.0. These results are tied to the adoption of a single star forming galaxy template; the presence of active galactic nuclei, and an evolution in their relative contribution to the mid-IR galaxy emission, will alter the overall number counts per cluster and their rate of evolution. Under the star formation assumption we infer the approximate total star formation rate per unit cluster mass (ΣSFR/M {sub cluster}). The evolution is similar, with ΣSFR/M {sub cluster} ∼ (1 + z){sup 5.4±1.9}. We show that this can be accounted for by the evolution of the IR-bright field population over the same redshift range; that is, the evolution can be attributed entirely to the change in the in-falling field galaxy population. We show that the ΣSFR/M {sub cluster} (binned over all redshift) decreases with increasing cluster mass with a slope (ΣSFR/M{sub cluster}∼M{sub cluster}{sup -1.5±0.4}) consistent with the dependence of the stellar-to-total mass per unit cluster mass seen locally. The inferred star formation seen here could produce ∼5%-10% of the total stellar mass in massive clusters at z = 0, but we cannot constrain the descendant population, nor how rapidly the star-formation must shut-down once the galaxies have entered the cluster environment. Finally, we show a clear decrease in the number of IR

  8. Choosing a Cluster Sampling Design for Lot Quality Assurance Sampling Surveys

    PubMed Central

    Hund, Lauren; Bedrick, Edward J.; Pagano, Marcello

    2015-01-01

    Lot quality assurance sampling (LQAS) surveys are commonly used for monitoring and evaluation in resource-limited settings. Recently several methods have been proposed to combine LQAS with cluster sampling for more timely and cost-effective data collection. For some of these methods, the standard binomial model can be used for constructing decision rules as the clustering can be ignored. For other designs, considered here, clustering is accommodated in the design phase. In this paper, we compare these latter cluster LQAS methodologies and provide recommendations for choosing a cluster LQAS design. We compare technical differences in the three methods and determine situations in which the choice of method results in a substantively different design. We consider two different aspects of the methods: the distributional assumptions and the clustering parameterization. Further, we provide software tools for implementing each method and clarify misconceptions about these designs in the literature. We illustrate the differences in these methods using vaccination and nutrition cluster LQAS surveys as example designs. The cluster methods are not sensitive to the distributional assumptions but can result in substantially different designs (sample sizes) depending on the clustering parameterization. However, none of the clustering parameterizations used in the existing methods appears to be consistent with the observed data, and, consequently, choice between the cluster LQAS methods is not straightforward. Further research should attempt to characterize clustering patterns in specific applications and provide suggestions for best-practice cluster LQAS designs on a setting-specific basis. PMID:26125967

  9. Dynein Clusters into Lipid Microdomains on Phagosomes to Drive Rapid Transport toward Lysosomes

    PubMed Central

    Rai, Ashim; Pathak, Divya; Thakur, Shreyasi; Singh, Shampa; Dubey, Alok Kumar; Mallik, Roop

    2016-01-01

    Summary Diverse cellular processes are driven by motor proteins that are recruited to and generate force on lipid membranes. Surprisingly little is known about how membranes control the force from motors and how this may impact specific cellular functions. Here, we show that dynein motors physically cluster into microdomains on the membrane of a phagosome as it matures inside cells. Such geometrical reorganization allows many dyneins within a cluster to generate cooperative force on a single microtubule. This results in rapid directed transport of the phagosome toward microtubule minus ends, likely promoting phagolysosome fusion and pathogen degradation. We show that lipophosphoglycan, the major molecule implicated in immune evasion of Leishmania donovani, inhibits phagosome motion by disrupting the clustering and therefore the cooperative force generation of dynein. These findings appear relevant to several pathogens that prevent phagosome-lysosome fusion by targeting lipid microdomains on phagosomes. PMID:26853472

  10. Dynein Clusters into Lipid Microdomains on Phagosomes to Drive Rapid Transport toward Lysosomes.

    PubMed

    Rai, Ashim; Pathak, Divya; Thakur, Shreyasi; Singh, Shampa; Dubey, Alok Kumar; Mallik, Roop

    2016-02-11

    Diverse cellular processes are driven by motor proteins that are recruited to and generate force on lipid membranes. Surprisingly little is known about how membranes control the force from motors and how this may impact specific cellular functions. Here, we show that dynein motors physically cluster into microdomains on the membrane of a phagosome as it matures inside cells. Such geometrical reorganization allows many dyneins within a cluster to generate cooperative force on a single microtubule. This results in rapid directed transport of the phagosome toward microtubule minus ends, likely promoting phagolysosome fusion and pathogen degradation. We show that lipophosphoglycan, the major molecule implicated in immune evasion of Leishmania donovani, inhibits phagosome motion by disrupting the clustering and therefore the cooperative force generation of dynein. These findings appear relevant to several pathogens that prevent phagosome-lysosome fusion by targeting lipid microdomains on phagosomes. PMID:26853472

  11. The ACS Virgo Cluster Survey. XIV. Analysis of Color-Magnitude Relations in Globular Cluster Systems

    NASA Astrophysics Data System (ADS)

    Mieske, Steffen; Jordán, Andrés; Côté, Patrick; Kissler-Patig, Markus; Peng, Eric W.; Ferrarese, Laura; Blakeslee, John P.; Mei, Simona; Merritt, David; Tonry, John L.; West, Michael J.

    2006-12-01

    We examine the correlation between globular cluster (GC) color and magnitude using HST ACS imaging for a sample of 79 early-type galaxies (-21.7Cluster Survey. Using the KMM mixture modeling algorithm, we find a highly significant correlation, γz≡d(g-z)/dz=-0.037+/-0.004, between color and magnitude for the subpopulation of blue GCs in the co-added GC color-magnitude diagram of the three brightest Virgo Cluster galaxies (M49, M87, and M60): brighter GCs are redder than their fainter counterparts. For the single GC systems of M87 and M60, we find similar correlations; M49 does not appear to show a significant trend. There is no correlation between (g-z) and Mz for GCs of the red subpopulation. The correlation γg≡d(g-z)/dg for the blue subpopulation is much weaker than d(g-z)/dz. Using Monte Carlo simulations, we attribute this finding to the fact that the blue subpopulation in Mg extends to higher luminosities than does the red subpopulation, which biases the KMM fit results. The correlation between color and Mz thus is a real effect: this conclusion is supported by biweight fits to the same color distributions. We identify two environmental dependencies that influence the derived color-magnitude relation: (1) the slope decreases in significance with decreasing galaxy luminosity; and (2) the slope is stronger for GC populations located at smaller galactocentric distances. We examine several physical mechanisms that might give rise to the observed color-magnitude relation: (1) presence of contaminators; (2) accretion of GCs from low-mass galaxies; (3) stochastic effects; (4) the capture of field stars by individual GCs; and (5) GC self-enrichment. We conclude that self-enrichment and field-star capture, or a combination of these processes, offer the most promising means of explaining our observations. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope

  12. Glass formation and cluster evolution in the rapidly solidified monatomic metallic liquid Ta under high pressure

    NASA Astrophysics Data System (ADS)

    Jiang, Dejun; Wen, Dadong; Tian, Zean; Liu, Rangsu

    2016-12-01

    Molecular dynamics (MD) simulations have been performed to examine the glass formation and cluster evolution during the rapid solidification of monatomic metallic liquid Ta under high pressure. The atomic structures in the systems are characterized by the radical distribution function (RDF), Honeycutt-Anderson (H-A) bond-type index method and cluster-type index method (CTIM). It is observed that the defective icosahedra play the critical role in the formation of Ta monatomic metallic glasses (MGs) rather than (12 0 12 0) perfect icosahedra, which have been identified as the basic local atomic units in many multi-component MGs. With the increase of pressure P, the fraction of icosahedral type clusters decreases remarkably in Ta MGs, while the fraction of bcc type clusters rises evidently. The evolution of vitrification degree (DSRO or DMRO) of the rapidly cooled metal Ta system further reveals that a higher pressure P is disadvantageous to the formation of Ta monatomic MGs. The weaker glass forming ability (GFA) of liquid metal Ta obtained under higher pressure P can be contributed to the decrease of DSRO or DMRO which is induced by increasing high pressure P to some extent.

  13. Virtual Sky Surveys and Multi-wavelength Investigations of Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Nord, Brian D.

    2010-12-01

    The advent of large and overlapping sky surveys brings promise of a new era in the study of galaxy clusters and dark energy. Clusters have been used for decades as faithful buoys of space-time, tracing cosmic evolution through their matter content and spatial distribution. High-fidelity tracking relies on a robust connection between observable cluster signatures and the underlying dark matter content, which is otherwise invisible. Until now, clusters have been mostly viewed through independent signals in distinct wavebands. The next era of cluster cosmology may be led by multi-variate, cross-waveband detections and analyses of clusters, where different facets of clusters can be cross-correlated to develop a more complete, unified picture of cluster populations. To these ends, in this dissertation, I perform multi-variate analyses of galaxy cluster populations and develop a simulated sky survey, with which to prepare for the next generation of multi-wavelength cluster observations. First, in a new multi-variate framework, I quantify the effects of observational biases on measures of the cluster distribution function and on cosmological constraints derived from X-ray cluster populations. I also demonstrate the indispensability of the multi-variate approach in measuring the evolution of X-ray galaxy clusters; without it, we find that the combination of scatter, intrinsic correlation and irrevocable survey flux limits substantially confuses any measure of redshift evolution. Next, I construct the Millennium Gas Simulation-Virtual Sky Survey (MGSVSS), a multi-wavelength mock sky derived from an N-body gas-dynamic simulation. The MGSVSS contains both sub-mm and optical wavelength sky signals to redshift, z = 1., in a 5 x 5deg2 field of view, with O (103) halos, O (104) optically selected clusters, and O (102) clusters selected via the Sunyaev-Zel'dovich (SZ) signature. The SZ sky also includes a minimal level of sky and instrumental noise, which nearly mimics that of

  14. HeCS-SZ: The Hectospec Survey of Sunyaev-Zeldovich-selected Clusters

    NASA Astrophysics Data System (ADS)

    Rines, Kenneth J.; Geller, Margaret J.; Diaferio, Antonaldo; Hwang, Ho Seong

    2016-03-01

    We estimate cluster masses and velocity dispersions for 123 clusters from optical spectroscopy to compare the Sunyaev-Zeldovich (SZ) mass proxy and dynamical masses. Our new survey, HeCS-SZ (Hectospec Cluster Survey of SZ-selected clusters), includes 7721 new or remeasured redshifts from MMT/Hectospec observations of 21 SZ-selected clusters at redshifts z = 0.05-0.20. We supplement the Hectospec data with spectra from the Sloan Digital Sky Survey (SDSS) and cluster data from the Cluster Infall Regions in SDSS project and the Hectospec Cluster Survey, our Hectospec survey of clusters selected by X-ray flux. We measure the scaling relation between velocity dispersion and SZ mass estimates from the integrated Compton parameter for an SZ-complete sample of 83 clusters. The observed relation agrees very well with a simple virial scaling from mass (based on SZ) to velocity dispersion. The SZ mass estimates (calibrated with hydrostatic X-ray mass estimates) are not significantly biased compared to dynamical mass estimates under the assumption of small velocity bias of galaxies compared to dark matter particles. Significant mass bias in SZ mass estimates could relieve tension between cosmological results from Planck SZ cluster counts and Planck CMB data. In principle, SZ mass bias and velocity bias of galaxies could conspire to yield good agreement, but the required velocity bias is {σ }{galaxy}≈ 0.77{σ }{DM}, outside the range of recent models of velocity bias in the literature. More likely, SZ mass bias and velocity bias are both small, and the tension between SZ cluster counts and CMB data requires another explanation.

  15. The Effects of Halo Assembly Bias on Self-Calibration in Galaxy Cluster Surveys

    SciTech Connect

    Wu, Hao-Yi; Rozo, Eduardo; Wechsler, Risa H.

    2008-08-07

    Self-calibration techniques for analyzing galaxy cluster counts utilize the abundance and the clustering amplitude of dark matter halos. These properties simultaneously constrain cosmological parameters and the cluster observable-mass relation. It was recently discovered that the clustering amplitude of halos depends not only on the halo mass, but also on various secondary variables, such as the halo formation time and the concentration; these dependences are collectively termed 'assembly bias'. Applying modified Fisher matrix formalism, we explore whether these secondary variables have a significant impact on the study of dark energy properties using the self-calibration technique in current (SDSS) and the near future (DES, SPT, and LSST) cluster surveys. The impact of the secondary dependence is determined by (1) the scatter in the observable-mass relation and (2) the correlation between observable and secondary variables. We find that for optical surveys, the secondary dependence does not significantly influence an SDSS-like survey; however, it may affect a DES-like survey (given the high scatter currently expected from optical clusters) and an LSST-like survey (even for low scatter values and low correlations). For an SZ survey such as SPT, the impact of secondary dependence is insignificant if the scatter is 20% or lower but can be enhanced by the potential high scatter values introduced by a highly-correlated background. Accurate modeling of the assembly bias is necessary for cluster self-calibration in the era of precision cosmology.

  16. A 1400-MHz survey of 1478 Abell clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Owen, F. N.; White, R. A.; Hilldrup, K. C.; Hanisch, R. J.

    1982-01-01

    Observations of 1478 Abell clusters of galaxies with the NRAO 91-m telescope at 1400 MHz are reported. The measured beam shape was deconvolved from the measured source Gaussian fits in order to estimate the source size and position angle. All detected sources within 0.5 corrected Abell cluster radii are listed, including the cluster number, richness class, distance class, magnitude of the tenth brightest galaxy, redshift estimate, corrected cluster radius in arcmin, right ascension and error, declination and error, total flux density and error, and angular structure for each source.

  17. Performance of small cluster surveys and the clustered LQAS design to estimate local-level vaccination coverage in Mali

    PubMed Central

    2012-01-01

    Background Estimation of vaccination coverage at the local level is essential to identify communities that may require additional support. Cluster surveys can be used in resource-poor settings, when population figures are inaccurate. To be feasible, cluster samples need to be small, without losing robustness of results. The clustered LQAS (CLQAS) approach has been proposed as an alternative, as smaller sample sizes are required. Methods We explored (i) the efficiency of cluster surveys of decreasing sample size through bootstrapping analysis and (ii) the performance of CLQAS under three alternative sampling plans to classify local VC, using data from a survey carried out in Mali after mass vaccination against meningococcal meningitis group A. Results VC estimates provided by a 10 × 15 cluster survey design were reasonably robust. We used them to classify health areas in three categories and guide mop-up activities: i) health areas not requiring supplemental activities; ii) health areas requiring additional vaccination; iii) health areas requiring further evaluation. As sample size decreased (from 10 × 15 to 10 × 3), standard error of VC and ICC estimates were increasingly unstable. Results of CLQAS simulations were not accurate for most health areas, with an overall risk of misclassification greater than 0.25 in one health area out of three. It was greater than 0.50 in one health area out of two under two of the three sampling plans. Conclusions Small sample cluster surveys (10 × 15) are acceptably robust for classification of VC at local level. We do not recommend the CLQAS method as currently formulated for evaluating vaccination programmes. PMID:23057445

  18. A Survey on Node Clustering in Cognitive Radio Wireless Sensor Networks.

    PubMed

    Joshi, Gyanendra Prasad; Kim, Sung Won

    2016-01-01

    Cognitive radio wireless sensor networks (CR-WSNs) have attracted a great deal of attention recently due to the emerging spectrum scarcity issue. This work attempts to provide a detailed analysis of the role of node clustering in CR-WSNs. We outline the objectives, requirements, and advantages of node clustering in CR-WSNs. We describe how a CR-WSN with node clustering differs from conventional wireless sensor networks, and we discuss its characteristics, architecture, and topologies. We survey the existing clustering algorithms and compare their objectives and features. We suggest how clustering issues and challenges can be handled. PMID:27626421

  19. Dusty Starbursts and the Formation of Elliptical Galaxies: A SCUBA-2 Survey of a z = 1.46 Cluster

    NASA Astrophysics Data System (ADS)

    Ma, C.-J.; Smail, Ian; Swinbank, A. M.; Simpson, J. M.; Thomson, A. P.; Chen, C.-C.; Danielson, A. L. R.; Hilton, M.; Tadaki, K.; Stott, J. P.; Kodama, T.

    2015-06-01

    We report the results of a deep SCUBA-2 850 and 450 μm survey for dust-obscured ultra-/luminous infrared galaxies (U/LIRGs) in the field of the z = 1.46 cluster XCS J2215.9-1738. We detect a striking overdensity of submillimeter sources coincident with the core of this cluster: ˜3-4 × higher than expected in a blank field. We use the likely radio and mid-infrared counterparts to show that the bulk of these submillimeter sources have spectroscopic or photometric redshifts that place them in the cluster and that their multiwavelength properties are consistent with this association. The average far-infrared luminosities of these galaxies are (1.0 ± 0.1) × 1012 {L}⊙ , placing them on the U/LIRG boundary. Using the total star formation occurring in the obscured U/LIRG population within the cluster, we show that the resulting mass-normalized star formation rate for this system supports previous claims of a rapid increase in star formation activity in cluster cores out to z˜ 1.5, which must be associated with the ongoing formation of the early-type galaxies that reside in massive clusters today. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  20. Exploring the z~1 Sky with the Massive and Distant Clusters of WISE Survey

    NASA Astrophysics Data System (ADS)

    Gonzalez, Anthony H.; MaDCoWS Team

    2016-01-01

    The Massive and Distant Clusters of WISE Survey (MaDCoWS) is a comprehensive program to detect and characterize the most massive galaxy clusters in the Universe at z~1 over the full extragalactic sky. The survey employs color-selection of WISE sources coupled with a wavelet smoothing algorithm to identify overdensities at this epoch. I will present an overview of the survey and present the status of our search within the PanSTARRS footprint, which has yielded several thousand cluster candidates. MaDCoWS is efficiently isolating the cluster population at this epoch, and I will show recent results from targeted follow-up observations, including confirmation of a 1015 solar mass cluster at z=1.19.

  1. A Survey of Popular R Packages for Cluster Analysis

    ERIC Educational Resources Information Center

    Flynt, Abby; Dean, Nema

    2016-01-01

    Cluster analysis is a set of statistical methods for discovering new group/class structure when exploring data sets. This article reviews the following popular libraries/commands in the R software language for applying different types of cluster analysis: from the stats library, the kmeans, and hclust functions; the mclust library; the poLCA…

  2. CLUSTER LENSING PROFILES DERIVED FROM A REDSHIFT ENHANCEMENT OF MAGNIFIED BOSS-SURVEY GALAXIES

    SciTech Connect

    Coupon, Jean; Umetsu, Keiichi; Broadhurst, Tom

    2013-07-20

    We report the first detection of a redshift-depth enhancement of background galaxies magnified by foreground clusters. Using 300,000 BOSS survey galaxies with accurate spectroscopic redshifts, we measure their mean redshift depth behind four large samples of optically selected clusters from the Sloan Digital Sky Survey (SDSS) surveys, totaling 5000-15,000 clusters. A clear trend of increasing mean redshift toward the cluster centers is found, averaged over each of the four cluster samples. In addition, we find similar but noisier behavior for an independent X-ray sample of 158 clusters lying in the foreground of the current BOSS sky area. By adopting the mass-richness relationships appropriate for each survey, we compare our results with theoretical predictions for each of the four SDSS cluster catalogs. The radial form of this redshift enhancement is well fitted by a richness-to-mass weighted composite Navarro-Frenk-White profile with an effective mass ranging between M{sub 200} {approx} 1.4-1.8 Multiplication-Sign 10{sup 14} M{sub Sun} for the optically detected cluster samples, and M{sub 200} {approx} 5.0 Multiplication-Sign 10{sup 14} M{sub Sun} for the X-ray sample. This lensing detection helps to establish the credibility of these SDSS cluster surveys, and provides a normalization for their respective mass-richness relations. In the context of the upcoming bigBOSS, Subaru Prime Focus Spectrograph, and EUCLID-NISP spectroscopic surveys, this method represents an independent means of deriving the masses of cluster samples for examining the cosmological evolution, and provides a relatively clean consistency check of weak-lensing measurements, free from the systematic limitations of shear calibration.

  3. Rapid polyvalent screening for largescale environmental Spiroplasma surveys

    PubMed Central

    French, Frank E.; Whitcomb, Robert F.; Williamson, David L.; Regassa, Laura B.

    2009-01-01

    Surface serology is an important determinant in Spiroplasma systematics. Reciprocal antigen/antibody reactions between spiroplasmas and individual antisera delineate the 38 described groups and species. However, reciprocal serology is impractical for large-scale studies. This report describes a successful, streamlined polyvalent screening approach used to examine isolates from an environmental survey. PMID:24031412

  4. The 400 Square Degree ROSAT PSPC Galaxy Cluster Survey: Catalog and Statistical Calibration

    NASA Astrophysics Data System (ADS)

    Burenin, R. A.; Vikhlinin, A.; Hornstrup, A.; Ebeling, H.; Quintana, H.; Mescheryakov, A.

    2007-10-01

    We present a catalog of galaxy clusters detected in a new ROSAT PSPC survey. The survey is optimized to sample, at high redshifts, the mass range corresponding to T>5 keV clusters at z=0. Technically, our survey is the extension of the 160 square degree survey (160d). We use the same detection algorithm, thus preserving high quality of the resulting sample; the main difference is a significant increase in sky coverage. The new survey covers 397 deg2 and is based on 1610 high Galactic latitude ROSAT PSPC pointings, virtually all pointed ROSAT data suitable for the detection of distant clusters. The search volume for X-ray luminous clusters within z<1 exceeds that of the entire local universe (z<0.1). We detected 287 extended X-ray sources with fluxes f>1.4×10-13 ergs s-1 cm-2 in the 0.5-2 keV energy band, of which 266 (93%) are optically confirmed as galaxy clusters, groups or individual elliptical galaxies. This paper provides a description of the input data, the statistical calibration of the survey via Monte Carlo simulations, and the catalog of detected clusters. We also compare the basic results to those from previous, smaller area surveys and find good agreement for the logN-logS distribution and the local X-ray luminosity function. Our sample clearly shows a decrease in the number density for the most luminous clusters at z>0.3. The comparison of our ROSAT-derived fluxes with the accurate Chandra measurements for a subset of high-redshift clusters demonstrates the validity of the 400 square degree survey's statistical calibration.

  5. An Empirical Taxonomy of Youths' Fears: Cluster Analysis of the American Fear Survey Schedule

    ERIC Educational Resources Information Center

    Burnham, Joy J.; Schaefer, Barbara A.; Giesen, Judy

    2006-01-01

    Fears profiles among children and adolescents were explored using the Fear Survey Schedule for Children-American version (FSSC-AM; J.J. Burnham, 1995, 2005). Eight cluster profiles were identified via multistage Euclidean grouping and supported by homogeneity coefficients and replication. Four clusters reflected overall level of fears (i.e., very…

  6. The INfrared Survey of Young Nebulous Clusters (IN-SYNC): Surveying the Dynamics and Star Formation Histories of Young Clusters with APOGEE

    NASA Astrophysics Data System (ADS)

    Covey, Kevin R.; Cottaar, Michiel; Foster, Jonathan B.; Da Rio, Nicola; Tan, Jonathan; Meyer, Michael; Nidever, David L.; Flaherty, Kevin M.; Arce, Hector G.; Rebull, Luisa M.; Chojnowski, S. Drew; Frinchaboy, Peter M.; Hearty, Fred R.; Majewski, Steven R.; Skrutskie, Michael F.; Stassun, Keivan; Wilson, John C.; Zasowski, Gail

    2015-01-01

    Young clusters are the most prolific sites of star formation in the Milky Way, but demographic studies indicate that relatively few of the Milky Way's stellar clusters persist as bound structures for 100 Myrs or longer. Uniform & precise measurements of the stellar populations and internal dynamics of these regions are difficult to obtain, however, particularly for extremely young clusters whose optical visibility is greatly hampered by their parental molecular cloud. The INfrared Survey of Young Nebulous Clusters (IN-SYNC), an SDSS-III ancillary science program, leverages the stability and multiplex capability of the APOGEE spectrograph to obtain high resolution spectra at near-infrared wavelengths, where photospheric emission is better able to penetrate the dusty shrouds that surround sites of active star formation. We summarize our recent measurements of the kinematics and stellar populations of IC 348 and NGC 1333, two young clusters in the Perseus Molecular Cloud, and of the members of the Orion Nebula Cluster (ONC) and L1641 filament in the Orion molecular complex. These measurements highlight the dynamically 'warm' environment within these young clusters, and suggest a range of stellar radii within these quasi-single-age populations. We close with a preview of plans for continuing this work as part of the APOGEE-2 science portfolio: self-consistent measurements of the kinematics and star formation histories for clusters spanning a range of initial conditions and ages will provide a opportunity to disentangle the mechanisms that drive the formation and dissolution of sites of active star formation.

  7. An H-alpha survey of cluster spirals - Comparison of star formation in clusters and the field

    NASA Technical Reports Server (NTRS)

    Moss, C.; Whittle, M.

    1993-01-01

    In an objective prism survey of eight nearby Abell clusters, we have detected H-alpha emission from 77 out of a total of 201 CGCG spiral galaxies. We find that detection of H alpha emission is approximately independent of galaxy absolute magnitude, distance to the cluster center, and the presence of a bar. However, tidally distorted spirals are much more likely to be detected than undistorted spirals. Furthermore, there is a strong tendency for tidally distorted spirals to have compact nuclear emission rather than more extended disk-wide emission. When compared to field spirals, we find that late-type (Sc and Sc-Irr) cluster spirals have less H alpha emission, while early-type (Sa and Sab) cluster spirals can have significantly enhanced emission. The enhanced emission is most likely to be due to tidally induced star formation from galaxy-galaxy interactions.

  8. The snapshot Hubble U-band cluster survey (SHUCS). II. The star cluster population of NGC 2997

    SciTech Connect

    Ryon, J. E.; Gallagher, J. S. III; Adamo, A.; Bastian, N.; Smith, L. J.; Konstantopoulos, I. S.; Larsen, S.; Zackrisson, E.

    2014-08-01

    We study the star cluster population of NGC 2997, a giant spiral galaxy located at 9.5 Mpc and targeted by the Snapshot Hubble U-band Cluster Survey (SHUCS). Combining our U-band imaging from SHUCS with archival BVI imaging from the Hubble Space Telescope, we select a high confidence sample of clusters in the circumnuclear ring and disk through a combination of automatic detection procedures and visual inspection. The cluster luminosity functions in all four filters can be approximated by power laws with indices of –1.7 to –2.3. Some deviations from pure power-law shape are observed, hinting at the presence of a high-mass truncation in the cluster mass function. However, upon inspection of the cluster mass function, we find it is consistent with a pure power law of index –2.2 ± 0.2 despite a slight bend at ∼2.5 × 10{sup 4} M {sub ☉}. No statistically significant truncation is observed. From the cluster age distributions, we find a low rate of disruption (ζ ∼ –0.1) in both the disk and circumnuclear ring. Finally, we estimate the cluster formation efficiency (Γ) over the last 100 Myr in each region, finding 7% ± 2% for the disk, 12% ± 4% for the circumnuclear ring, and 10% ± 3% for the entire UBVI footprint. This study highlights the need for wide-field UBVI coverage of galaxies to study cluster populations in detail, though a small sample of clusters can provide significant insight into the characteristics of the population.

  9. Rapid Mapping Method Based on Free Blocks of Surveys

    NASA Astrophysics Data System (ADS)

    Yu, Xianwen; Wang, Huiqing; Wang, Jinling

    2016-06-01

    While producing large-scale larger than 1:2000 maps in cities or towns, the obstruction from buildings leads to difficult and heavy tasks of measuring mapping control points. In order to avoid measuring the mapping control points and shorten the time of fieldwork, in this paper, a quick mapping method is proposed. This method adjusts many free blocks of surveys together, and transforms the points from all free blocks of surveys into the same coordinate system. The entire surveying area is divided into many free blocks, and connection points are set on the boundaries between free blocks. An independent coordinate system of every free block is established via completely free station technology, and the coordinates of the connection points, detail points and control points in every free block in the corresponding independent coordinate systems are obtained based on poly-directional open traverses. Error equations are established based on connection points, which are determined together to obtain the transformation parameters. All points are transformed from the independent coordinate systems to a transitional coordinate system via the transformation parameters. Several control points are then measured by GPS in a geodetic coordinate system. All the points can then be transformed from the transitional coordinate system to the geodetic coordinate system. In this paper, the implementation process and mathematical formulas of the new method are presented in detail, and the formula to estimate the precision of surveys is given. An example has demonstrated that the precision of using the new method could meet large-scale mapping needs.

  10. The ACS Survey of Galactic Globular Clusters. VIII. Effects of Environment on Globular Cluster Global Mass Functions

    NASA Astrophysics Data System (ADS)

    Paust, Nathaniel E. Q.; Reid, I. Neill; Piotto, Giampaolo; Aparicio, Antonio; Anderson, Jay; Sarajedini, Ata; Bedin, Luigi R.; Chaboyer, Brian; Dotter, Aaron; Hempel, Maren; Majewski, Steven; Marín-Franch, A.; Milone, Antonino; Rosenberg, Alfred; Siegel, Michael

    2010-02-01

    We have used observations obtained as part of the Hubble Space Telescope/ACS Survey of Galactic Globular Clusters to construct global present-day mass functions for 17 globular clusters utilizing multi-mass King models to extrapolate from our observations to the global cluster behavior. The global present-day mass functions for these clusters are well matched by power laws from the turnoff, ≈0.8 M sun, to 0.2-0.3 M sun on the lower main sequence. The slopes of those power-law fits, α, have been correlated with an extensive set of intrinsic and extrinsic cluster properties to investigate which parameters may influence the form of the present-day mass function. We do not confirm previous suggestions of correlations between α and either metallicity or Galactic location. However, we do find a strong statistical correlation with the related parameters central surface brightness, μ V , and inferred central density, ρ0. The correlation is such that clusters with denser cores (stronger binding energy) tend to have steeper mass functions (a higher proportion of low-mass stars), suggesting that dynamical evolution due to external interactions may have played a key role in determining α. Thus, the present-day mass function may owe more to nurture than to nature. Detailed modeling of external dynamical effects is therefore a requisite for determining the initial mass function for Galactic globular clusters.

  11. THE ACS SURVEY OF GALACTIC GLOBULAR CLUSTERS. VIII. EFFECTS OF ENVIRONMENT ON GLOBULAR CLUSTER GLOBAL MASS FUNCTIONS

    SciTech Connect

    Paust, Nathaniel E. Q.; Reid, I. Neill; Anderson, Jay E-mail: inr@stsci.edu

    2010-02-15

    We have used observations obtained as part of the Hubble Space Telescope/ACS Survey of Galactic Globular Clusters to construct global present-day mass functions for 17 globular clusters utilizing multi-mass King models to extrapolate from our observations to the global cluster behavior. The global present-day mass functions for these clusters are well matched by power laws from the turnoff, {approx}0.8 M {sub sun}, to 0.2-0.3 M {sub sun} on the lower main sequence. The slopes of those power-law fits, {alpha}, have been correlated with an extensive set of intrinsic and extrinsic cluster properties to investigate which parameters may influence the form of the present-day mass function. We do not confirm previous suggestions of correlations between {alpha} and either metallicity or Galactic location. However, we do find a strong statistical correlation with the related parameters central surface brightness, {mu} {sub V}, and inferred central density, {rho}{sub 0}. The correlation is such that clusters with denser cores (stronger binding energy) tend to have steeper mass functions (a higher proportion of low-mass stars), suggesting that dynamical evolution due to external interactions may have played a key role in determining {alpha}. Thus, the present-day mass function may owe more to nurture than to nature. Detailed modeling of external dynamical effects is therefore a requisite for determining the initial mass function for Galactic globular clusters.

  12. A survey by HEAO 1 of clusters of galaxies. III - The complete Abell catalog

    NASA Technical Reports Server (NTRS)

    Johnson, M. W.; Cruddace, R. G.; Wood, K. S.; Ulmer, M. P.; Kowalski, M. P.

    1983-01-01

    A catalog of 128 X-ray emitting clusters, including the Virgo Cluster, is presented. Ninety-one of these are new identifications. The catalog was obtained by searching the HEAO 1 survey observations for coincidences of X-ray sources with Abell clusters. The distribution of these sources in the sky has been examined in search of associations with other Abell clusters, with a null result. The X-ray luminosity has been correlated with cluster richness, but no association with Bautz-Morgan class has been found. The cluster luminosity function has been evaluated, and using this function the contribution of clusters to the diffuse X-ray background radiation has been estimated. It amounts to less than 15% at 2 keV and 3% at 6 keV.

  13. Cool Core Bias in Sunyaev-Zel’dovich Galaxy Cluster Surveys

    DOE PAGESBeta

    Lin, Henry W.; McDonald, Michael; Benson, Bradford; Miller, Eric

    2015-03-18

    Sunyaev-Zeldovich (SZ) surveys find massive clusters of galaxies by measuring the inverse Compton scattering of cosmic microwave background off of intra-cluster gas. The cluster selection function from such surveys is expected to be nearly independent of redshift and cluster astrophysics. In this work, we estimate the effect on the observed SZ signal of centrally-peaked gas density profiles (cool cores) and radio emission from the brightest cluster galaxy (BCG) by creating mock observations of a sample of clusters that span the observed range of classical cooling rates and radio luminosities. For each cluster, we make simulated SZ observations by the Southmore » Pole Telescope and characterize the cluster selection function, but note that our results are broadly applicable to other SZ surveys. We find that the inclusion of a cool core can cause a change in the measured SPT significance of a cluster between 0.01%–10% at z > 0.3, increasing with cuspiness of the cool core and angular size on the sky of the cluster (i.e., decreasing redshift, increasing mass). We provide quantitative estimates of the bias in the SZ signal as a function of a gas density cuspiness parameter, redshift, mass, and the 1.4 GHz radio luminosity of the central AGN. Based on this work, we estimate that, for the Phoenix cluster (one of the strongest cool cores known), the presence of a cool core is biasing the SZ significance high by ~6%. The ubiquity of radio galaxies at the centers of cool core clusters will offset the cool core bias to varying degrees« less

  14. Cool Core Bias in Sunyaev-Zel’dovich Galaxy Cluster Surveys

    SciTech Connect

    Lin, Henry W.; McDonald, Michael; Benson, Bradford; Miller, Eric

    2015-03-18

    Sunyaev-Zeldovich (SZ) surveys find massive clusters of galaxies by measuring the inverse Compton scattering of cosmic microwave background off of intra-cluster gas. The cluster selection function from such surveys is expected to be nearly independent of redshift and cluster astrophysics. In this work, we estimate the effect on the observed SZ signal of centrally-peaked gas density profiles (cool cores) and radio emission from the brightest cluster galaxy (BCG) by creating mock observations of a sample of clusters that span the observed range of classical cooling rates and radio luminosities. For each cluster, we make simulated SZ observations by the South Pole Telescope and characterize the cluster selection function, but note that our results are broadly applicable to other SZ surveys. We find that the inclusion of a cool core can cause a change in the measured SPT significance of a cluster between 0.01%–10% at z > 0.3, increasing with cuspiness of the cool core and angular size on the sky of the cluster (i.e., decreasing redshift, increasing mass). We provide quantitative estimates of the bias in the SZ signal as a function of a gas density cuspiness parameter, redshift, mass, and the 1.4 GHz radio luminosity of the central AGN. Based on this work, we estimate that, for the Phoenix cluster (one of the strongest cool cores known), the presence of a cool core is biasing the SZ significance high by ~6%. The ubiquity of radio galaxies at the centers of cool core clusters will offset the cool core bias to varying degrees

  15. Myeloperoxidase-derived oxidants rapidly oxidize and disrupt zinc-cysteine/histidine clusters in proteins.

    PubMed

    Cook, Naomi L; Pattison, David I; Davies, Michael J

    2012-12-01

    Zinc is an abundant cellular transition metal ion, which binds avidly to protein cysteine (Cys) and histidine (His) residues to form zinc-Cys/His clusters; these play a key role in the function of many proteins (e.g., DNA binding and repair enzymes, transcription factors, nitric oxide synthase). Leukocyte-derived myeloperoxidase generates powerful oxidants including hypochlorous (HOCl), hypobromous (HOBr), and hypothiocyanous (HOSCN) acids from H(2)O(2) and (pseudo)halide ions. Excessive or misplaced formation of these species is associated with cellular dysfunction, apoptosis and necrosis, and multiple inflammatory diseases. HOCl and HOBr react rapidly with sulfur-containing compounds, and HOSCN reacts specifically with thiols. Consequently, we hypothesized that zinc-Cys/His clusters would be targets for these oxidants, and the activity of such enzymes would be perturbed. This hypothesis has been tested using yeast alcohol dehydrogenase (YADH), which contains a well-characterized Zn(1)Cys(2)His(1) cluster. Incubation of YADH with pathologically relevant concentrations of HOSCN, HOCl, and HOBr resulted in rapid oxidation of the protein (rate constants, determined by competition kinetics, for reaction of HOCl and HOSCN with YADH being (3.3±0.9)×10(8) and (2.9±0.4)×10(4) M(-1) s(-1) per YADH monomer, respectively), loss of enzyme activity, Zn(2+) release, changes in protein structure (particularly formation of disulfide cross-links), and oxidation of Cys residues. The loss of enzyme activity correlated with Zn(2+) release, loss of thiols, and changes in protein structure. We conclude that exposure of zinc-Cys/His clusters to inflammatory oxidants can result in impaired protein activity, thiol oxidation, and Zn(2+) release. These reactions may contribute to inflammation-induced tissue damage. PMID:23032100

  16. Cosmological interpretation of large X-ray cluster surveys with CR-HR diagrams

    NASA Astrophysics Data System (ADS)

    Clerc, Nicolas

    2012-09-01

    Large samples of galaxy clusters collected in X-ray observations are able to tightly constrain cosmological scenarios by probing the mass function of large structures and its evolution with time. It is clear now that selection effects, mass observable relation, cosmological model and related uncertainties must be jointly apprehended in order to fully and correctly exploit such surveys. The CR-HR method relies on X-ray observables only -- Count-Rates and Hardness Ratios of clusters in different energy bands -- and thus bypasses the computation of mass for each individual cluster. By modeling the observed sample of cluster properties down to the instrumental level, it self-consistently includes the various model uncertainties. I will show how it can be applied to large cosmological X-ray surveys by presenting forecasts in realistic situations. Then I will present the results we obtained from our large (~90 deg^2), serendipitous XMM-Newton cluster survey, X-CLASS. I will put particular emphasis on cluster X-ray scaling laws, and underline some inconsistencies with recent analyses. I will finally discuss the applicability of this method to a large upcoming survey, namely the eRosita full-sky survey.

  17. THE HUBBLE SPACE TELESCOPE CLUSTER SUPERNOVA SURVEY. II. THE TYPE Ia SUPERNOVA RATE IN HIGH-REDSHIFT GALAXY CLUSTERS

    SciTech Connect

    Barbary, K.; Amanullah, R.; Fakhouri, H. K.; Goldhaber, G.; Huang, X.; Aldering, G.; Dawson, K. S.; Faccioli, L.; Hsiao, E.; Brodwin, M.; Connolly, N.; Doi, M.; Ihara, Y.; Eisenhardt, P.; Fadeyev, V.; Fruchter, A. S.; Gilbank, D. G.; Gladders, M. D.; Goobar, A.; Hattori, T.; Collaboration: Supernova Cosmology Project; and others

    2012-01-20

    We report a measurement of the Type Ia supernova (SN Ia) rate in galaxy clusters at 0.9 < z < 1.46 from the Hubble Space Telescope Cluster Supernova Survey. This is the first cluster SN Ia rate measurement with detected z > 0.9 SNe. Finding 8 {+-} 1 cluster SNe Ia, we determine an SN Ia rate of 0.50{sup +0.23}{sub -0.19} (stat){sup +0.10}{sub -0.09} (sys) h{sup 2}{sub 70} SNuB (SNuB {identical_to} 10{sup -12} SNe L{sup -1}{sub Sun ,B} yr{sup -1}). In units of stellar mass, this translates to 0.36{sup +0.16}{sub -0.13} (stat){sup +0.07}{sub -0.06} (sys) h{sup 2}{sub 70} SNuM (SNuM {identical_to} 10{sup -12} SNe M{sup -1}{sub Sun} yr{sup -1}). This represents a factor of Almost-Equal-To 5 {+-} 2 increase over measurements of the cluster rate at z < 0.2. We parameterize the late-time SN Ia delay time distribution (DTD) with a power law: {Psi}(t){proportional_to}t{sup s} . Under the approximation of a single-burst cluster formation redshift of z{sub f} = 3, our rate measurement in combination with lower-redshift cluster SN Ia rates constrains s = -1.41{sup +0.47}{sub -0.40}, consistent with measurements of the DTD in the field. This measurement is generally consistent with expectations for the 'double degenerate' scenario and inconsistent with some models for the 'single degenerate' scenario predicting a steeper DTD at large delay times. We check for environmental dependence and the influence of younger stellar populations by calculating the rate specifically in cluster red-sequence galaxies and in morphologically early-type galaxies, finding results similar to the full cluster rate. Finally, the upper limit of one hostless cluster SN Ia detected in the survey implies that the fraction of stars in the intra-cluster medium is less than 0.47 (95% confidence), consistent with measurements at lower redshifts.

  18. Conditional pseudolikelihood methods for clustered ordinal, multinomial, or count outcomes with complex survey data.

    PubMed

    Brumback, Babette A; Cai, Zhuangyu; He, Zhulin; Zheng, Hao W; Dailey, Amy B

    2013-04-15

    In order to adjust individual-level covariate effects for confounding due to unmeasured neighborhood characteristics, we have recently developed conditional pseudolikelihood methods to estimate the parameters of a proportional odds model for clustered ordinal outcomes with complex survey data. The methods require sampling design joint probabilities for each within-neighborhood pair. In the present article, we develop a similar methodology for a baseline category logit model for clustered multinomial outcomes and for a loglinear model for clustered count outcomes. All of the estimators and asymptotic sampling distributions we present can be conveniently computed using standard logistic regression software for complex survey data, such as sas proc surveylogistic. We demonstrate validity of the methods theoretically and also empirically by using simulations. We apply the new method for clustered multinomial outcomes to data from the 2008 Florida Behavioral Risk Factor Surveillance System survey in order to investigate disparities in frequency of dental cleaning both unadjusted and adjusted for confounding by neighborhood. PMID:22976045

  19. Searching for Galaxy Clusters in the VST-KiDS Survey

    NASA Astrophysics Data System (ADS)

    Radovich, M.; Puddu, E.; Bellagamba, F.; Moscardini, L.; Roncarelli, M.; Getman, F.; Grado, A.

    We present the methods and first results of the search for galaxy clusters in the Kilo Degree Survey (KiDS). The adopted algorithm and the criterium for selecting the member galaxies are illustrated. Here we report the preliminary results obtained over a small area (7 deg2), and the comparison of our cluster candidates with those found in the RedMapper and SZ Planck catalogues; the analysis to a larger area (148 deg2) is currently in progress. By the KiDS cluster search, we expect to increase the completeness of the clusters catalogue to z = 0.6-0.7 compared to RedMapper.

  20. Cosmological Constraints from Galaxy Clusters and Clustering in the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Tinker, Jeremy

    2009-01-01

    I will present constraints on cosmological parameters from a combination of cluster mass to galaxy number ratios combined with halo occupation analysis of the galaxy autocorrelation function. In two-point clustering, cosmology an bias are degenerate; good fits to the correlation function can be obtained for a wide variety of comologies. However, in order to match the observed level of clustering, each cosmology predicts a different number of galaxies per unit mass at the cluster mass scale. A combination of DR7 galaxy clustering results and M/N data from the weak lensing analysis of the maxBCG catalog break the degeneracy between cosmology and bias, leading to constraints on \\Omega_m and \\sigma_8 that are competitive with current CMB results.

  1. A SURVEY OF CN AND CH VARIATIONS IN GALACTIC GLOBULAR CLUSTERS FROM SLOAN DIGITAL SKY SURVEY SPECTROSCOPY

    SciTech Connect

    Smolinski, Jason P.; Beers, Timothy C.; Lee, Young Sun; Martell, Sarah L. E-mail: beers@pa.msu.edu E-mail: martell@ari.uni-heidelberg.de

    2011-10-15

    We present a homogeneous survey of the CN and CH band strengths in eight Galactic globular clusters observed during the course of the Sloan Extension for Galactic Understanding and Exploration sub-survey of the Sloan Digital Sky Survey. We confirm the existence of a bimodal CN distribution among red giant branch (RGB) stars in all of the clusters with metallicity greater than [Fe/H] = -1.7; the lowest metallicity cluster with an observed CN bimodality is M53, with [Fe/H] {approx_equal} -2.1. There is also some evidence for individual CN groups on the subgiant branches of M92, M2, and M13, and on the RGBs of M92 and NGC 5053. Finally, we quantify the correlation between overall cluster metallicity and the slope of the CN band strength-luminosity plot as a means of further demonstrating the level of CN enrichment in cluster giants. Our results agree well with previous studies reported in the literature.

  2. Rapid geo-acoustic characterization from a seismic survey

    NASA Astrophysics Data System (ADS)

    Heaney, Kevin D.; Sternlicht, Daniel; Teranishi, Arthur; Castille, Brett; Hamilton, Michael

    2002-05-01

    A recent transmission loss experiment was conducted in Long Beach Harbor for the THUMS Long Beach Company. The objective of the experiment was to measure the range at which the received level was 160 dB for compliance with Marine Mammal regulations. This short experiment provided the opportunity to test the rapid geo-acoustic characterization (RGC) algorithm and perform real-time geo-acoustic inversions from a seismic source. The airgun source transmitted pulses every 20 s corresponding to every 45 m. The water depth was 10-15 m and the water was assumed to be iso-velocity. The data quality was excellent, providing clear striation patterns in the broadband frequency display. The RGC algorithm matches the observed time-spread, striation slope, and TL slope to precomputed values using a normal mode algorithm and parametric geo-acoustic profiles based on Hamilton and Bachman's model. Precomputation of the acoustic observables, combined with real-time signal processing permits real time geo-acoustic characterization.

  3. THE ACS FORNAX CLUSTER SURVEY. VI. THE NUCLEI OF EARLY-TYPE GALAXIES IN THE FORNAX CLUSTER

    SciTech Connect

    Turner, Monica L.; Cote, Patrick; Ferrarese, Laura; Blakeslee, John P.; Jordan, Andres; Mei, Simona; Peng, Eric W.; West, Michael J.

    2012-11-15

    The Advanced Camera for Surveys (ACS) Fornax Cluster Survey is a Hubble Space Telescope program to image 43 early-type galaxies in the Fornax cluster, using the F475W and F850LP bandpasses of the ACS. We employ both one-dimensional and two-dimensional techniques to characterize the properties of the stellar nuclei in these galaxies, defined as the central 'luminosity excesses', relative to a Sersic model fitted to the underlying host. We find 72% {+-} 13% of our sample (31 galaxies) to be nucleated, with only three of the nuclei offset by more than 0.''5 from their galaxy photocenter, and with the majority of nuclei having colors bluer than their hosts. The nuclei are observed to be larger, and brighter, than typical Fornax globular clusters and to follow different structural scaling relations. A comparison of our results to those from the ACS Virgo Cluster Survey reveals striking similarities in the properties of the nuclei belonging to these different environments. We briefly review a variety of proposed formation models and conclude that, for the low-mass galaxies in our sample, the most important mechanism for nucleus growth is probably infall of star clusters through dynamical friction, while for higher mass galaxies, gas accretion triggered by mergers, accretions, and tidal torques is likely to dominate, with the relative importance of these two processes varying smoothly as a function of galaxy mass. Some intermediate-mass galaxies in our sample show a complexity in their inner structure that may be the signature of the 'hybrid nuclei' that arose through parallel formation channels.

  4. The Swift X-Ray Telescope Cluster Survey. III. Cluster Catalog from 2005-2012 Archival Data

    NASA Astrophysics Data System (ADS)

    Liu, Teng; Tozzi, Paolo; Tundo, Elena; Moretti, Alberto; Rosati, Piero; Wang, Jun-Xian; Tagliaferri, Gianpiero; Campana, Sergio; Giavalisco, Mauro

    2015-02-01

    We present the Swift X-ray Cluster Survey (SWXCS) catalog obtained using archival data from the X-ray telescope (XRT) on board the Swift satellite acquired from 2005 February to 2012 November, extending the first release of the SWXCS. The catalog provides positions, soft fluxes, and, when possible, optical counterparts for a flux-limited sample of X-ray group and cluster candidates. We consider the fields with Galactic latitude |b| > 20° to avoid high H I column densities. We discard all of the observations targeted at groups or clusters of galaxies, as well as particular extragalactic fields not suitable to search for faint extended sources. We finally select ~3000 useful fields covering a total solid angle of ~400 deg2. We identify extended source candidates in the soft-band (0.5-2 keV) images of these fields using the software EXSdetect, which is specifically calibrated for the XRT data. Extensive simulations are used to evaluate contamination and completeness as a function of the source signal, allowing us to minimize the number of spurious detections and to robustly assess the selection function. Our catalog includes 263 candidate galaxy clusters and groups down to a flux limit of 7 × 10-15 erg cm-2 s-1 in the soft band, and the logN-logS is in very good agreement with previous deep X-ray surveys. The final list of sources is cross-correlated with published optical, X-ray, and Sunyaev-Zeldovich catalogs of clusters. We find that 137 sources have been previously identified as clusters in the literature in independent surveys, while 126 are new detections. Currently, we have collected redshift information for 158 sources (60% of the entire sample). Once the optical follow-up and the X-ray spectral analysis of the sources are complete, the SWXCS will provide a large and well-defined catalog of groups and clusters of galaxies to perform statistical studies of cluster properties and tests of cosmological models.

  5. THE SWIFT X-RAY TELESCOPE CLUSTER SURVEY. III. CLUSTER CATALOG FROM 2005-2012 ARCHIVAL DATA

    SciTech Connect

    Liu, Teng; Wang, Jun-Xian; Tozzi, Paolo; Tundo, Elena; Moretti, Alberto; Rosati, Piero; Tagliaferri, Gianpiero; Campana, Sergio; Giavalisco, Mauro

    2015-02-01

    We present the Swift X-ray Cluster Survey (SWXCS) catalog obtained using archival data from the X-ray telescope (XRT) on board the Swift satellite acquired from 2005 February to 2012 November, extending the first release of the SWXCS. The catalog provides positions, soft fluxes, and, when possible, optical counterparts for a flux-limited sample of X-ray group and cluster candidates. We consider the fields with Galactic latitude |b| > 20° to avoid high H I column densities. We discard all of the observations targeted at groups or clusters of galaxies, as well as particular extragalactic fields not suitable to search for faint extended sources. We finally select ∼3000 useful fields covering a total solid angle of ∼400 deg{sup 2}. We identify extended source candidates in the soft-band (0.5-2 keV) images of these fields using the software EXSdetect, which is specifically calibrated for the XRT data. Extensive simulations are used to evaluate contamination and completeness as a function of the source signal, allowing us to minimize the number of spurious detections and to robustly assess the selection function. Our catalog includes 263 candidate galaxy clusters and groups down to a flux limit of 7 × 10{sup –15} erg cm{sup –2} s{sup –1} in the soft band, and the logN-logS is in very good agreement with previous deep X-ray surveys. The final list of sources is cross-correlated with published optical, X-ray, and Sunyaev-Zeldovich catalogs of clusters. We find that 137 sources have been previously identified as clusters in the literature in independent surveys, while 126 are new detections. Currently, we have collected redshift information for 158 sources (60% of the entire sample). Once the optical follow-up and the X-ray spectral analysis of the sources are complete, the SWXCS will provide a large and well-defined catalog of groups and clusters of galaxies to perform statistical studies of cluster properties and tests of cosmological models.

  6. Strong Lensing Mass Reconstruction: from Frontier Fields to the Typical Lensing Clusters of Future Surveys

    NASA Astrophysics Data System (ADS)

    Sharon, Keren

    2015-08-01

    Driven by the unprecedented wealth of high quality data that is accumulating for the Frontier Fields, they are becoming some of the best-studied strong lensing clusters to date, and probably the next few years. As will be discussed intensively in this focus meeting, the FF prove transformative for many fields: from studies of the high redshift Universe, to the assembly and structure of the clusters themselves. The FF data and the extensive collaborative effort around this program will also allow us to examine and improve upon current lens modeling techniques. Strong lensing is a powerful tool for mass reconstruction of the cores of galaxy clusters of all scales, providing an estimate of the total (dark and seen) projected mass density distribution out to ~0.5 Mpc. Though SL mass may be biased by contribution from structures along the line of sight, its strength is that it is relatively insensitive to assumptions on cluster baryon astrophysics and dynamical state. Like the Frontier Fields clusters, the most "famous" strong lensing clusters are at the high mass end; they lens dozens of background sources into multiple images, providing ample lensing constraints. In this talk, I will focus on how we can leverage what we learn from modeling the FF clusters in strong lensing studies of the hundreds of clusters that will be discovered in upcoming surveys. In typical clusters, unlike the Frontier Fields, the Bullet Cluster and A1689, we observe only one to a handful of background sources, and have limited lensing constraints. I will describe the limitations that such a configuration imposes on strong lens modeling, highlight measurements that are robust to the richness of lensing evidence, and address the sources of uncertainty and what sort of information can help reduce those uncertainties. This category of lensing clusters is most relevant to the wide cluster surveys of the future.

  7. A Targeted, Distant Galaxy Cluster Survey Using Bent, Double-Lobed Radio Sources

    NASA Astrophysics Data System (ADS)

    Blanton, Elizabeth L.; Paterno-Mahler, Rachel; Wing, Joshua; Ashby, Matthew; Brodwin, Mark

    2014-06-01

    We are conducting a large survey of distant clusters of galaxies using bent, double-lobed radio sources as tracers. Bent, double-lobed radio sources are driven by AGN and achieve their morphologies through interaction with the surrounding gas found in clusters. The lobes can become swept back during large-scale cluster mergers that set the intracluster medium in motion, or through more gentle sloshing motions of cluster cores driven by more minor interactions. These types of radio sources may be found in clusters that are highly disturbed as well as those that are relatively relaxed. In addition, they are found in clusters with a large range of masses. By the nature of their selection, all of the clusters will contain radio-loud active galaxies, so they are expected to be sites of AGN feedback. Based on low-redshift studies, these types of sources can be used to identify rich clusters with a success rate of ~60% (or ~80% if poor clusters and groups are included). We present our survey of 653 bent-double radio sources with optical hosts too faint to appear in the SDSS. The sample was observed in the infrared with Spitzer, and we estimate it will reveal ~400 distant clusters or proto-clusters in the redshift range z ~ 0.7 -- 3.0. The sample of bent-doubles contains both quasars and radio galaxies enabling us to study both radiative and kinetic mode feedback in cluster and group environments at a wide range of redshifts.

  8. THE MASSIVE AND DISTANT CLUSTERS OF WISE SURVEY. II. INITIAL SPECTROSCOPIC CONFIRMATION OF z ∼ 1 GALAXY CLUSTERS SELECTED FROM 10,000 deg{sup 2}

    SciTech Connect

    Stanford, S. A.; Gonzalez, Anthony H.; Gettings, Daniel P.; Brodwin, Mark; Eisenhardt, Peter R. M.; Stern, Daniel; Wylezalek, Dominika

    2014-08-01

    We present optical and infrared imaging and optical spectroscopy of galaxy clusters which were identified as part of an all-sky search for high-redshift galaxy clusters, the Massive and Distant Clusters of WISE Survey (MaDCoWS). The initial phase of MaDCoWS combined infrared data from the all-sky data release of the Wide-field Infrared Survey Explorer (WISE) with optical data from the Sloan Digital Sky Survey to select probable z ∼ 1 clusters of galaxies over an area of 10,000 deg{sup 2}. Our spectroscopy confirms 19 new clusters at 0.7 < z < 1.3, half of which are at z > 1, demonstrating the viability of using WISE to identify high-redshift galaxy clusters. The next phase of MaDCoWS will use the greater depth of the AllWISE data release to identify even higher redshift cluster candidates.

  9. Indoleamine Hallucinogens in Cluster Headache: Results of the Clusterbusters Medication Use Survey.

    PubMed

    Schindler, Emmanuelle A D; Gottschalk, Christopher H; Weil, Marsha J; Shapiro, Robert E; Wright, Douglas A; Sewell, Richard Andrew

    2015-01-01

    Cluster headache is one of the most debilitating pain syndromes. A significant number of patients are refractory to conventional therapies. The Clusterbusters.org medication use survey sought to characterize the effects of both conventional and alternative medications used in cluster headache. Participants were recruited from cluster headache websites and headache clinics. The final analysis included responses from 496 participants. The survey was modeled after previously published surveys and was available online. Most responses were chosen from a list, though others were free-texted. Conventional abortive and preventative medications were identified and their efficacies agreed with those previously published. The indoleamine hallucinogens, psilocybin, lysergic acid diethylamide, and lysergic acid amide, were comparable to or more efficacious than most conventional medications. These agents were also perceived to shorten/abort a cluster period and bring chronic cluster headache into remission more so than conventional medications. Furthermore, infrequent and non-hallucinogenic doses were reported to be efficacious. Findings provide additional evidence that several indoleamine hallucinogens are rated as effective in treating cluster headache. These data reinforce the need for further investigation of the effects of these and related compounds in cluster headache under experimentally controlled settings. PMID:26595349

  10. The OCCASO survey: presentation and radial velocities of 12 Milky Way open clusters

    NASA Astrophysics Data System (ADS)

    Casamiquela, L.; Carrera, R.; Jordi, C.; Balaguer-Núñez, L.; Pancino, E.; Hidalgo, S. L.; Martínez-Vázquez, C. E.; Murabito, S.; del Pino, A.; Aparicio, A.; Blanco-Cuaresma, S.; Gallart, C.

    2016-05-01

    Open clusters (OCs) are crucial for studying the formation and evolution of the Galactic disc. However, the lack of a large number of OCs analysed homogeneously hampers the investigations about chemical patterns and the existence of Galactocentric radial and vertical gradients, or an age-metallicity relation. To overcome this, we have designed the Open Cluster Chemical Abundances from Spanish Observatories (OCCASO) survey. We aim to provide homogeneous radial velocities, physical parameters and individual chemical abundances of six or more red clump stars for a sample of 25 old and intermediate-age OCs visible from the Northern hemisphere. To do so, we use high-resolution spectroscopic facilities (R ≥ 62 000) available at Spanish observatories. We present the motivation, design and current status of the survey, together with the first data release of radial velocities for 77 stars in 12 OCs, which represents about 50 per cent of the survey. We include clusters never studied with high-resolution spectroscopy before (NGC 1907, NGC 6991, NGC 7762), and clusters in common with other large spectroscopic surveys like the Gaia-ESO Survey (NGC 6705) and Apache Point Observatory Galactic Evolution Experiment (NGC 2682 and NGC 6819). We perform internal comparisons between instruments to evaluate and correct internal systematics of the results, and compare our radial velocities with previous determinations in the literature, when available. Finally, radial velocities for each cluster are used to perform a preliminary kinematic study in relation with the Galactic disc.

  11. The Two-Point Spatial Correlation Function for the MX Northern Abell Cluster Survey

    NASA Astrophysics Data System (ADS)

    Miller, C. J.; Slinglend, K. A.; Batuski, D. J.; Hill, J.

    1997-12-01

    The results from the COBE satellite show the existence of structure in the cosmic microwave background radiation on scales ~ 10% or more of the horizon scale of the Universe. Rich clusters of galaxies from the Abell/ACO catalogs show evidence of structure on scales of 100h(-1) Mpc and hold the promise of confirming structure on the scale of the COBE results. However, previous analyses for large-scale structure based on the clusters in these catalogs suffer from small sample sizes, imcomplete samples, and large uncertainties in the measured data. Our efforts with the MX Cluster Redshift Survey have resulted in galaxy redshifts for 95 rich Abell clusters returning 88 positive cluster identifications. Five cluster fields did not supply enough data for cluster positions and two clusters were found to be simply projections of galaxies strung out along the line of sight. By obtaining an average of 9 member galaxy redshifts per cluster, we have greatly reduced uncertainty in cluster locations. The Abell catalog is now 98% complete out to m10 <= 16.8. This complete sample has provided us with the necessary data to calculate the two-point spatial correlation function, xi (r), characterized by the slope of its power-law fit gamma and a scale length r_o. Preliminary results give gamma = -2.26+/-0.14 and r_o = 21.9+/- 1.5 h(-1) Mpc. These results are then compared with other spatial analyses based on different samples.

  12. A sparse-sampling strategy for the estimation of large-scale clustering from redshift surveys

    NASA Astrophysics Data System (ADS)

    Kaiser, N.

    1986-04-01

    It is shown that a fractional faint-magnitude limited redshift survey can significantly reduce the uncertainty in the two-point function for a given telescope time investment, in the estimation of large scale clustering. The signal-to-noise ratio for a 1-in-20 bright galaxy sample is roughly twice that provided by a same-cost complete survey, and this performance is the same as for a larger complete survey of about seven times the cost. A similar performance increase is achieved with a wide-field telescope multiple redshift collection from a close to full sky coverage survey. Little performance improvement is seen for smaller multiply collected surveys ideally sampled at a 1-in-10 bright galaxy rate. The optimum sampling fraction for Abell's rich clusters is found to be close to unity, with little sparse sampling performance improvement.

  13. THE XMM CLUSTER SURVEY: THE STELLAR MASS ASSEMBLY OF FOSSIL GALAXIES

    SciTech Connect

    Harrison, Craig D.; Miller, Christopher J.; Richards, Joseph W.; Deadman, Paul-James; Lloyd-Davies, E. J.; Kathy Romer, A.; Mehrtens, Nicola; Liddle, Andrew R.; Hoyle, Ben; Hilton, Matt; Stott, John P.; Capozzi, Diego; Collins, Chris A.; Sahlen, Martin; Stanford, S. Adam; Viana, Pedro T. P.

    2012-06-10

    This paper presents both the result of a search for fossil systems (FSs) within the XMM Cluster Survey and the Sloan Digital Sky Survey and the results of a study of the stellar mass assembly and stellar populations of their fossil galaxies. In total, 17 groups and clusters are identified at z < 0.25 with large magnitude gaps between the first and fourth brightest galaxies. All the information necessary to classify these systems as fossils is provided. For both groups and clusters, the total and fractional luminosity of the brightest galaxy is positively correlated with the magnitude gap. The brightest galaxies in FSs (called fossil galaxies) have stellar populations and star formation histories which are similar to normal brightest cluster galaxies (BCGs). However, at fixed group/cluster mass, the stellar masses of the fossil galaxies are larger compared to normal BCGs, a fact that holds true over a wide range of group/cluster masses. Moreover, the fossil galaxies are found to contain a significant fraction of the total optical luminosity of the group/cluster within 0.5 R{sub 200}, as much as 85%, compared to the non-fossils, which can have as little as 10%. Our results suggest that FSs formed early and in the highest density regions of the universe and that fossil galaxies represent the end products of galaxy mergers in groups and clusters.

  14. H-alpha Imaging Survey of Low-Redshift Cluster Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Barkhouse, Wayne; Kalawila, Sandanuwan; Rude, Cody; Sultanova, Madina; Archer, Haylee Nichole; Foote, Gregory

    2016-01-01

    We describe our on-going H-alpha imaging survey to measure the star formation activity of dwarf galaxies selected from a sample of low-redshift (0.02 < z< 0.15) galaxy clusters using the KPNO 4-meter telescope+Mosaic camera. H-alpha observations are obtained using the narrow-band BATC filters centered on the redshifted H-alpha emission line. The continuum-subtracted H-alpha images allow us to constrain star formation rates via the correlation between star formation and H-alpha luminosity and equivalent width. The impact of the cluster environment can be quantified using radial-dependent measures of the star formation rate within individual clusters, and by comparing clusters within our sample on a cluster-to-cluster basis. Comparison of our H-alpha measurements to CFHT u-band imaging data of our cluster sample, permits us to explore the correlation between the UV continuum and H-alpha emission of the dwarf galaxy population. The goal of our survey is to further understand the mechanism that is responsible for the enhancement/quenching of star formation as dwarf galaxies fall into the galaxy cluster environment.

  15. The REFLEX II galaxy cluster survey: power spectrum analysis

    NASA Astrophysics Data System (ADS)

    Balaguera-Antolínez, A.; Sánchez, Ariel G.; Böhringer, H.; Collins, C.; Guzzo, L.; Phleps, S.

    2011-05-01

    We present the power spectrum of galaxy clusters measured from the new ROSAT-ESO Flux-Limited X-Ray (REFLEX II) galaxy cluster catalogue. This new sample extends the flux limit of the original REFLEX catalogue to 1.8 × 10-12 erg s-1 cm-2, yielding a total of 911 clusters with ≥94 per cent completeness in redshift follow-up. The analysis of the data is improved by creating a set of 100 REFLEX II-catalogue-like mock galaxy cluster catalogues built from a suite of large-volume Λ cold dark matter (ΛCDM) N-body simulations (L-BASICC II). The measured power spectrum is in agreement with the predictions from a ΛCDM cosmological model. The measurements show the expected increase in the amplitude of the power spectrum with increasing X-ray luminosity. On large scales, we show that the shape of the measured power spectrum is compatible with a scale-independent bias and provide a model for the amplitude that allows us to connect our measurements with a cosmological model. By implementing a luminosity-dependent power-spectrum estimator, we observe that the power spectrum measured from the REFLEX II sample is weakly affected by flux-selection effects. The shape of the measured power spectrum is compatible with a featureless power spectrum on scales k > 0.01 h Mpc-1 and hence no statistically significant signal of baryonic acoustic oscillations can be detected. We show that the measured REFLEX II power spectrum displays signatures of non-linear evolution.

  16. Real-Time Patient Survey Data During Routine Clinical Activities for Rapid-Cycle Quality Improvement

    PubMed Central

    Jones, Robert E

    2015-01-01

    Background Surveying patients is increasingly important for evaluating and improving health care delivery, but practical survey strategies during routine care activities have not been available. Objective We examined the feasibility of conducting routine patient surveys in a primary care clinic using commercially available technology (Web-based survey creation, deployment on tablet computers, cloud-based management of survey data) to expedite and enhance several steps in data collection and management for rapid quality improvement cycles. Methods We used a Web-based data management tool (survey creation, deployment on tablet computers, real-time data accumulation and display of survey results) to conduct four patient surveys during routine clinic sessions over a one-month period. Each survey consisted of three questions and focused on a specific patient care domain (dental care, waiting room experience, care access/continuity, Internet connectivity). Results Of the 727 available patients during clinic survey days, 316 patients (43.4%) attempted the survey, and 293 (40.3%) completed the survey. For the four 3-question surveys, the average time per survey was overall 40.4 seconds, with a range of 5.4 to 20.3 seconds for individual questions. Yes/No questions took less time than multiple choice questions (average 9.6 seconds versus 14.0). Average response time showed no clear pattern by order of questions or by proctor strategy, but monotonically increased with number of words in the question (<20 words, 21-30 words, >30 words)—8.0, 11.8, 16.8, seconds, respectively. Conclusions This technology-enabled data management system helped capture patient opinions, accelerate turnaround of survey data, with minimal impact on a busy primary care clinic. This new model of patient survey data management is feasible and sustainable in a busy office setting, supports and engages clinicians in the quality improvement process, and harmonizes with the vision of a learning health

  17. Mapping the Epidemiology of Yaws in the Solomon Islands: A Cluster Randomized Survey

    PubMed Central

    Marks, Michael; Vahi, Ventis; Sokana, Oliver; Puiahi, Elliot; Pavluck, Alex; Zhang, Zaixing; Dalipanda, Tenneth; Bottomley, Christian; Mabey, David C.; Solomon, Anthony W.

    2015-01-01

    Yaws, a non-venereal treponemal disease, is targeted for eradication by 2020 but accurate epidemiological data to guide control programs remain sparse. The Solomon Islands reports the second highest number of cases of yaws worldwide. We conducted a cluster randomized survey of yaws in two provinces of the Solomon Islands. One thousand four hundred and ninety-seven (1,497) children 5–14 years of age were examined. Clinical signs of active yaws were found in 79 children (5.5%), whereas 140 children (9.4%) had evidence of healed yaws lesions. Four hundred and seventy (470) (31.4%) children had a positive Treponema pallidum particle agglutination assay (TPPA). Two hundred and eighty-five (285) children (19%) had a positive TPPA and rapid plasma regain assay. Risk of yaws increased with age and was more common in males. The prevalence of yaws at village level was the major risk factor for infection. Our findings suggest the village, not the household, should be the unit of treatment in the World Health Organization (WHO) yaws eradication strategy. PMID:25422395

  18. Mapping the epidemiology of yaws in the Solomon Islands: a cluster randomized survey.

    PubMed

    Marks, Michael; Vahi, Ventis; Sokana, Oliver; Puiahi, Elliot; Pavluck, Alex; Zhang, Zaixing; Dalipanda, Tenneth; Bottomley, Christian; Mabey, David C; Solomon, Anthony W

    2015-01-01

    Yaws, a non-venereal treponemal disease, is targeted for eradication by 2020 but accurate epidemiological data to guide control programs remain sparse. The Solomon Islands reports the second highest number of cases of yaws worldwide. We conducted a cluster randomized survey of yaws in two provinces of the Solomon Islands. One thousand four hundred and ninety-seven (1,497) children 5-14 years of age were examined. Clinical signs of active yaws were found in 79 children (5.5%), whereas 140 children (9.4%) had evidence of healed yaws lesions. Four hundred and seventy (470) (31.4%) children had a positive Treponema pallidum particle agglutination assay (TPPA). Two hundred and eighty-five (285) children (19%) had a positive TPPA and rapid plasma regain assay. Risk of yaws increased with age and was more common in males. The prevalence of yaws at village level was the major risk factor for infection. Our findings suggest the village, not the household, should be the unit of treatment in the World Health Organization (WHO) yaws eradication strategy. PMID:25422395

  19. Too Little, Too Late: How the Tidal Evolution of Hot Jupiters Affects Transit Surveys of Clusters

    NASA Technical Reports Server (NTRS)

    Debes, John H.; Jackson, Brian

    2010-01-01

    The tidal evolution of hot Jupiters may change the efficiency of transit surveys of stellar clusters. The orbital decay that hot Jupiters suffer may result in their destruction, leaving fewer transiting planets in older clusters. We calculate the impact tidal evolution has for different assumed stellar populations, including that of 47 Tuc, a globular cluster that was the focus of an intense HST search for transits. We find that in older clusters one expects to detect fewer transiting planets by a factor of two for surveys sensitive to Jupiter-like planets in orbits out to 0.5 AU, and up to a factor of 25 for surveys sensitive to Jupiter-like planets in orbits out to 0.08 AU. Additionally, tidal evolution affects the distribution of transiting planets as a function of semi-major axis, producing larger orbital period gaps for transiting planets as the age of the cluster increases. Tidal evolution can explain the lack of detected exoplanets in 47 Tuc without invoking other mechanisms. Four open clusters residing within the Kepler fields of view have ages that span 0.4-8 Gyr-if Kepler can observe a significant number of planets in these clusters, it will provide key tests for our tidal evolution hypothesis. Finally, our results suggest that observers wishing to discover transiting planets in clusters must have sufficient accuracy to detect lower mass planets, search larger numbers of cluster members, or have longer observation windows to be confident that a significant number of transits will occur for a population of stars.

  20. The most distant galaxy clusters in the SPT Spitzer Deep Field Survey

    NASA Astrophysics Data System (ADS)

    Rettura, Alessandro; Stanford, S. A.; Stern, D.; Mei, S.; Brodwin, M.; Gonzalez, A. H.; Gettings, D.; Ashby, M.; Bartlett, J.; Rosati, P.

    2014-01-01

    We present a sample of more than 300 galaxy cluster candidates at z>1.3 selected within 94 deg2 from the Spitzer SPT Deep Field (SSDF) survey. To discover distant clusters at z>1.3, we have used a three-filter algorithm based upon Spitzer/IRAC color ([3.6]-[4.5]>-0.1,AB) combined with a non-detection in shallow optical data. Our sample is selected to be a complete stellar mass-limited sample at z>1.3 and therefore has a well defined survey volume. The uniqueness of SSDF resides not just in its area, one of the very largest with Spitzer, but also in its coverage by deep observations for the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope (SPT). Deeper observations are also planned with the new SPT camera, SPTpol, that will reach, for the first time, SZ clusters up to 2 (George et al., 2012). This field also has deep X-ray observations from the XMM XXL Survey (Pierre et al., 2012). Thanks to this rich data set, we will be able to determine accurate cluster masses for the vast majority of our SSDF clusters at 1.3cluster population at an important epoch in their formation.

  1. The Gaia-ESO Survey: Kinematics of seven Galactic globular clusters

    NASA Astrophysics Data System (ADS)

    Lardo, C.; Pancino, E.; Bellazzini, M.; Bragaglia, A.; Donati, P.; Gilmore, G.; Randich, S.; Feltzing, S.; Jeffries, R. D.; Vallenari, A.; Alfaro, E. J.; Allende Prieto, C.; Flaccomio, E.; Koposov, S. E.; Recio-Blanco, A.; Bergemann, M.; Carraro, G.; Costado, M. T.; Damiani, F.; Hourihane, A.; Jofré, P.; de Laverny, P.; Marconi, G.; Masseron, T.; Morbidelli, L.; Sacco, G. G.; Worley, C. C.

    2015-01-01

    The Gaia-ESO survey is a large public spectroscopic survey aimed at investigating the origin and formation history of our Galaxy by collecting spectroscopy of representative samples (about 105 Milky Way stars) of all Galactic stellar populations, in the field and in clusters. The survey uses globular clusters as intra- and inter-survey calibrators, deriving stellar atmospheric parameters and abundances of a significant number of stars in clusters, along with radial velocity determinations. We used precise radial velocities of a large number of stars in seven globular clusters (NGC 1851, NGC 2808, NGC 4372, NGC 4833, NGC 5927, NGC 6752, and NGC 7078) to validate pipeline results and to preliminarily investigate the cluster internal kinematics. Radial velocity measurements were extracted from FLAMES/GIRAFFE spectra processed by the survey pipeline as part of the second internal data release of data products to ESO. We complemented our sample with ESO archival data obtained with different instrument configurations. Reliable radial velocity measurements for 1513 bona fide cluster star members were obtained in total. We measured systemic rotation, estimated central velocity dispersions, and present velocity dispersion profiles of all the selected clusters, providing the first velocity dispersion curve and the first estimate of the central velocitydispersion for the cluster NGC 5927. Finally, we explore the possible link between cluster kinematics and other physical parameters. The analysis we present here demonstrates that Gaia-ESO survey data are sufficiently accurate to be used in studies of kinematics of stellar systems and stellar populations in the Milky Way. Full Table 3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/A115Based on data products from observations made with ESO telescopes at the La Silla Paranal Observatory under programme 188.B-3002 (the

  2. Neutron Capture Elements in the Open Cluster Chemical Abundance & Mapping (OCCAM) Survey

    NASA Astrophysics Data System (ADS)

    O'Connell, Julia; Frinchaboy, Peter M.; Shetrone, Matthew D.; Majewski, Steven R.; Zasowski, Gail; Hearty, Fred R.

    2016-01-01

    The Open Cluster Chemical Abundance & Mapping (OCCAM) survey is a systematic survey of Galactic open clusters using data primarily from the SDSS-III/APOGEE-1 survey. The high-resolution (R=22,500), near-infrared (H-band) APOGEE-1 survey allows for cluster membership probability determination and analysis of light and iron-peak elements. Neutron capture elements, however, prove to be elusive in the IR region covered by APOGEE. In an effort to fully study detailed Galactic chemical evolution, we conducted a high resolution (R~60,000) spectroscopic abundance analysis of neutron capture elements for OCCAM clusters in the optical regime to complement the APOGEE results. We present results for ten open clusters using data obtained at McDonald Observatory with the 2.1m Otto Struve telescope and Sandiford Echelle Spectrograph. We see abundance trends for Ba II, La II and Eu II that are consistent with Galactic abundance patterns for these elements. Ce II appears to be slightly enhanced in all program stars with a median value of ~0.1 dex and a spread of 0.5 dex for the entire sample.

  3. A DEEP, WIDE-FIELD H{alpha} SURVEY OF NEARBY CLUSTERS OF GALAXIES: DATA

    SciTech Connect

    Sakai, Shoko; Kennicutt, Robert C. Jr.; Moss, Chris

    2012-04-01

    We present the results of a wide-field H{alpha} imaging survey of eight nearby (z = 0.02-0.03) Abell clusters. We have measured H{alpha} fluxes and equivalent widths for 465 galaxies, of which 360 are new detections. The survey was designed to obtain complete emission-line-selected inventories of star-forming galaxies in the inner regions of these clusters, extending to star formation rates below 0.1 M{sub Sun} yr{sup -1}. This paper describes the observations, data processing, and source identification procedures, and presents an H{alpha} and R-band catalog of detected cluster members and other candidates. Future papers in the series will use these data to study the completeness of spectroscopically based star formation surveys, and to quantify the effects of cluster environment on the present-day populations of star-forming galaxies. The data will also provide a valuable foundation for imaging surveys of redshifted H{alpha} emission in more distant clusters.

  4. SPATIAL ANISOTROPY OF GALAXY KINEMATICS IN SLOAN DIGITAL SKY SURVEY GALAXY CLUSTERS

    SciTech Connect

    Skielboe, Andreas; Wojtak, Radoslaw; Pedersen, Kristian; Rozo, Eduardo; Rykoff, Eli S.

    2012-10-10

    Measurements of galaxy cluster kinematics are important in understanding the dynamical state and evolution of clusters of galaxies, as well as constraining cosmological models. While it is well established that clusters exhibit non-spherical geometries, evident in the distribution of galaxies on the sky, azimuthal variations of galaxy kinematics within clusters have yet to be observed. Here we measure the azimuthal dependence of the line-of-sight velocity dispersion profile in a stacked sample of 1743 galaxy clusters from the Sloan Digital Sky Survey (SDSS). The clusters are drawn from the SDSS DR8 redMaPPer catalog. We find that the line-of-sight velocity dispersion of galaxies lying along the major axis of the central galaxy is larger than those that lie along the minor axis. This is the first observational detection of anisotropic kinematics of galaxies in clusters. We show that the result is consistent with predictions from numerical simulations. Furthermore, we find that the degree of projected anisotropy is strongly dependent on the line-of-sight orientation of the galaxy cluster, opening new possibilities for assessing systematics in optical cluster finding.

  5. A SUBMILLIMETER ARRAY SURVEY OF PROTOPLANETARY DISKS IN THE ORION NEBULA CLUSTER

    SciTech Connect

    Mann, Rita K.; Williams, Jonathan P. E-mail: jpw@ifa.hawaii.ed

    2010-12-10

    We present the full results of our three-year-long Submillimeter Array (SMA) survey of protoplanetary disks in the Orion Nebula Cluster. We imaged 23 fields at 880 {mu}m and 2 fields at 1330 {mu}m, covering an area of {approx}6.5 arcmin{sup 2} and containing 67 disks. We detected 42 disks with fluxes between 6 and 135 mJy and at rms noise levels between 0.6 and 5.3 mJy beam{sup -1}. Thermal dust emission above any free-free component was measured in 40 of the 42 detections, and the inferred disk masses range from 0.003 to 0.07 M{sub sun}. We find that disks located within 0.3 pc of {theta}{sup 1} Ori C have a truncated mass distribution, while disks located beyond 0.3 pc have masses more comparable to those found in low-mass star-forming regions. The disk mass distribution in Orion has a distance dependence, with a derived relationship max(M{sub disk}) = 0.046 M{sub sun}(d/0.3 pc){sup 0.33} for the maximum disk masses. We found evidence of grain growth in disk 197-427, the only disk detected at both 880 {mu}m and 1330 {mu}m with the SMA. Despite the rapid erosion of the outer parts of the Orion disks by photoevaporation, the potential for planet formation remains high in this massive star-forming region, with {approx}18% of the surveyed disks having masses {>=}0.01 M{sub sun} within 60 AU.

  6. The JCMT Gould Belt Survey: Dense Core Clusters in Orion B

    NASA Astrophysics Data System (ADS)

    Kirk, H.; Johnstone, D.; Di Francesco, J.; Lane, J.; Buckle, J.; Berry, D. S.; Broekhoven-Fiene, H.; Currie, M. J.; Fich, M.; Hatchell, J.; Jenness, T.; Mottram, J. C.; Nutter, D.; Pattle, K.; Pineda, J. E.; Quinn, C.; Salji, C.; Tisi, S.; Hogerheijde, M. R.; Ward-Thompson, D.; The JCMT Gould Belt Survey team

    2016-04-01

    The James Clerk Maxwell Telescope Gould Belt Legacy Survey obtained SCUBA-2 observations of dense cores within three sub-regions of Orion B: LDN 1622, NGC 2023/2024, and NGC 2068/2071, all of which contain clusters of cores. We present an analysis of the clustering properties of these cores, including the two-point correlation function and Cartwright’s Q parameter. We identify individual clusters of dense cores across all three regions using a minimal spanning tree technique, and find that in each cluster, the most massive cores tend to be centrally located. We also apply the independent M–Σ technique and find a strong correlation between core mass and the local surface density of cores. These two lines of evidence jointly suggest that some amount of mass segregation in clusters has happened already at the dense core stage.

  7. The JCMT Gould Belt Survey: Dense Core Clusters in Orion B

    NASA Astrophysics Data System (ADS)

    Kirk, H.; Johnstone, D.; Di Francesco, J.; Lane, J.; Buckle, J.; Berry, D. S.; Broekhoven-Fiene, H.; Currie, M. J.; Fich, M.; Hatchell, J.; Jenness, T.; Mottram, J. C.; Nutter, D.; Pattle, K.; Pineda, J. E.; Quinn, C.; Salji, C.; Tisi, S.; Hogerheijde, M. R.; Ward-Thompson, D.; The JCMT Gould Belt Survey Team

    2016-04-01

    The James Clerk Maxwell Telescope Gould Belt Legacy Survey obtained SCUBA-2 observations of dense cores within three sub-regions of Orion B: LDN 1622, NGC 2023/2024, and NGC 2068/2071, all of which contain clusters of cores. We present an analysis of the clustering properties of these cores, including the two-point correlation function and Cartwright’s Q parameter. We identify individual clusters of dense cores across all three regions using a minimal spanning tree technique, and find that in each cluster, the most massive cores tend to be centrally located. We also apply the independent M-Σ technique and find a strong correlation between core mass and the local surface density of cores. These two lines of evidence jointly suggest that some amount of mass segregation in clusters has happened already at the dense core stage.

  8. Prospects for clustering and lensing measurements with forthcoming intensity mapping and optical surveys

    NASA Astrophysics Data System (ADS)

    Pourtsidou, A.; Bacon, D.; Crittenden, R.; Metcalf, R. B.

    2016-06-01

    We explore the potential of using intensity mapping surveys (MeerKAT, SKA) and optical galaxy surveys (DES, LSST) to detect H I clustering and weak gravitational lensing of 21 cm emission in auto- and cross-correlation. Our forecasts show that high-precision measurements of the clustering and lensing signals can be made in the near future using the intensity mapping technique. Such studies can be used to test the intensity mapping method, and constrain parameters such as the H I density Ω _{H I}, the H I bias b_{H I} and the galaxy-H I correlation coefficient r_{H I-g}.

  9. VizieR Online Data Catalog: HST/ACS Coma Cluster Survey. X. (den Brok+, 2014)

    NASA Astrophysics Data System (ADS)

    den Brok, M.; Peletier, R. F.; Seth, A.; Balcells, M.; Dominguez, L.; Graham, A. W.; Carter, D.; Erwin, P.; Ferguson, H. C.; Goudfrooij, P.; Guzman, R.; Hoyos, C.; Jogee, S.; Lucey, J.; Phillipps, S.; Puzia, T.; Valentijn, E.; Kleijn, G. V.; Weinzirl, T.

    2015-05-01

    The Coma ACS Survey (Carter et al., 2008ApJS..176..424C) provides data in two passbands for 25 fields pointed at the core of the Coma cluster and at the outskirts. The exposure times in the two passbands, F814W and F475W (which are roughly equivalent to the IC and g band) were ~1400 and ~2600s. The original envisaged coverage of the cluster was much larger than 25 fields, but due to the ACS failure in 2008 January the survey was not completed. (2 data files).

  10. Public requests for cancer cluster investigations: a survey of state health departments.

    PubMed Central

    Trumbo, C W

    2000-01-01

    OBJECTIVES: This study examined the frequency of requests that state health departments investigate cancer clusters, the nature of those requests, and the resources available for the investigations. METHODS: A mail survey was sent to state health departments requesting data for 1997. RESULTS: Approximately 1100 cluster investigation requests were made in 1997. Most requests were made by citizens, and no pattern emerged for types of cancer or hazards suspected. States rate this work as average in importance and feel satisfied with the successfullness of their communication efforts. CONCLUSIONS: Few cluster inquiries require further investigation. Nonetheless, this interaction represents resources well spent in terms of public service and education. PMID:10937014

  11. Land-based lidar mapping: a new surveying technique to shed light on rapid topographic change

    USGS Publications Warehouse

    Collins, Brian D.; Kayen, Robert

    2006-01-01

    The rate of natural change in such dynamic environments as rivers and coastlines can sometimes overwhelm the monitoring capacity of conventional surveying methods. In response to this limitation, U.S. Geological Survey (USGS) scientists are pioneering new applications of light detection and ranging (lidar), a laser-based scanning technology that promises to greatly increase our ability to track rapid topographic changes and manage their impact on affected communities.

  12. X-ray survey of galaxy clusters in the SDSS Stripe 82 region

    NASA Astrophysics Data System (ADS)

    Durret, Florence; Takey, Ali

    2016-07-01

    We conducted a survey of galaxy clusters detected from XMM-Newton observations covering an area of 11.25 deg^2 in the Stripe 82 region of the Sloan Digital Sky Survey (SDSS). We found 94 X-ray cluster candidates from the third XMM-Newton serendipitous source catalogue (3XMM-DR5) and correlated this list with recently published X-ray and optically selected cluster catalogues to obtain optical confirmations and redshifts (between 0.05 and 1.19, with a median of 0.36) for 54 galaxy groups/clusters. Of these, 17 are newly X-ray discovered clusters and 45 systems with spectroscopic confirmations. Among the remaining candidates, 25 sources are distant cluster candidates (beyond a redshift of 0.6). We will present preliminary results on the X-ray and optical properties of these clusters: luminosities and temperatures of the X-ray gas, and optical properties of the galaxies (morphology, luminosity functions).

  13. The VMC survey. XI. Radial stellar population gradients in the galactic globular cluster 47 Tucanae

    SciTech Connect

    Li, Chengyuan; De Grijs, Richard; Deng, Licai; Rubele, Stefano; Girardi, Leo; Gullieuszik, Marco; Wang, Chuchu; Bekki, Kenji; For, Bi-Qing; Cioni, Maria-Rosa L.; Clementini, Gisella; Emerson, Jim; Groenewegen, Martin A. T.; Guandalini, Roald; Marconi, Marcella; Ripepi, Vincenzo; Piatti, Andrés E.; Van Loon, Jacco Th. E-mail: grijs@pku.edu.cn

    2014-07-20

    We present a deep near-infrared color-magnitude diagram of the Galactic globular cluster 47 Tucanae, obtained with the Visible and Infrared Survey Telescope for Astronomy (VISTA) as part of the VISTA near-infrared Y, J, K{sub s} survey of the Magellanic System (VMC). The cluster stars comprising both the subgiant and red giant branches exhibit apparent, continuous variations in color-magnitude space as a function of radius. Subgiant branch stars at larger radii are systematically brighter than their counterparts closer to the cluster core; similarly, red-giant-branch stars in the cluster's periphery are bluer than their more centrally located cousins. The observations can very well be described by adopting an age spread of ∼0.5 Gyr as well as radial gradients in both the cluster's helium abundance (Y) and metallicity (Z), which change gradually from (Y = 0.28, Z = 0.005) in the cluster core to (Y = 0.25, Z = 0.003) in its periphery. We conclude that the cluster's inner regions host a significant fraction of second-generation stars, which decreases with increasing radius; the stellar population in the 47 Tuc periphery is well approximated by a simple stellar population.

  14. A New Method for the Detection of Galaxy Clusters in X-Ray Surveys

    SciTech Connect

    Piacentine, J.M.; Marshall, P.J.; Peterson, J.R.; Andersson, K.E.

    2005-01-01

    For many years the power of counting clusters of galaxies as a function of their mass has been recognized as a powerful cosmological probe; however, we are only now beginning to acquire data from dedicated surveys with sufcient sky coverage and sensitivity to measure the cluster population out to distances where the dark energy came to dominate the Universe’s evolution. One such survey uses the XMM X-ray telescope to scan a large area of sky, detecting the X-ray photons from the hot plasma that lies in the deep potential wells of massive clusters of galaxies. These clusters appear as extended (not point-like) objects, each providing just a few hundred photons in a typical observation. The detection of extended sources in such a low signal-to-noise situation is an important problem in astrophysics: we attempt to solve it by using as much prior information as possible, translating our experience with wellmeasured clusters to define a “template” cluster that can be varied and matched to the features seen in the XMM images. In this work we adapt an existing Monte Carlo analysis code for this problem. Two detection templates were dened and their suitability explored using simulated data; the method was then applied to a publically avalable XMM observation of a “blank” field. Presented are the encouraging results of this series of experiments, suggesting that this approach continue to be developed for future cluster-identication endeavours.

  15. Galaxy clustering in the Two Micron All Sky Redshift Survey

    NASA Astrophysics Data System (ADS)

    Westover, Michael

    To make cosmological measurements using the galaxy distribution we must first understand galaxy biasing the way in which the galaxy distribution differs from the underlying matter distribution. Here I present studies of galaxy biasing using the Two Micron All Sky Redshift Survey, a near-infrared selected survey not subject to many of the selection effects that limit other samples. The relationship between galaxy bias and luminosity is steeper for our near- infrared selected sample than it is for optical samples, with b/b [low *] 0.73 + 0.24 L/L [low *] . I found no dependence upon luminosity in the relative bias between early and late morphologically typed galaxies once the mean dependence of bias upon luminosity was removed. I tested the relative biasing between early- and late-type galaxies using joint counts in cells. I found that a power law biasing model with b PL = 0.86-0.91 was a better fit than linear models. I did not see a significant increase in the quality of the fit when stochasticity was added to the model, in contrast with results from color- and spectral type-selected samples. I tested the hierarchical scaling hypothesis and confirmed that the scale factors S 3 , S 4 , and S 5 are independent of scale, as expected for a matter distribution evolved from Gaussian initial perturbations. There was no increase in the scale factors at large cell sizes as seen in some earlier surveys. I also measured the generalized dimensions D q using a multifractal analysis and found smaller values than have been seen in optically-selected surveys and simulations, indicating that galaxies in the near-infrared selected sample may be more likely to reside in filamentary rather than sheet-like structures.

  16. Surveying phylogenetic footprints in large gene clusters: applications to Hox cluster duplications.

    PubMed

    Prohaska, Sonja J; Fried, Claudia; Flamm, Christoph; Wagner, Günter P; Stadler, Peter F

    2004-05-01

    Evolutionarily conserved non-coding genomic sequences represent a potentially rich source for the discovery of gene regulatory regions. Since these elements are subject to stabilizing selection they evolve much more slowly than adjacent non-functional DNA. These so-called phylogenetic footprints can be detected by comparison of the sequences surrounding orthologous genes in different species. Therefore the loss of phylogenetic footprints as well as the acquisition of conserved non-coding sequences in some lineages, but not in others, can provide evidence for the evolutionary modification of cis-regulatory elements. We introduce here a statistical model of footprint evolution that allows us to estimate the loss of sequence conservation that can be attributed to gene loss and other structural reasons. This approach to studying the pattern of cis-regulatory element evolution, however, requires the comparison of relatively long sequences from many species. We have therefore developed an efficient software tool for the identification of corresponding footprints in long sequences from multiple species. We apply this novel method to the published sequences of HoxA clusters of shark, human, and the duplicated zebrafish and Takifugu clusters as well as the published HoxB cluster sequences. We find that there is a massive loss of sequence conservation in the intergenic region of the HoxA clusters, consistent with the finding in [Chiu et al., PNAS 99 (2002) 5492]. The loss of conservation after cluster duplication is more extensive than expected from structural reasons. This suggests that binding site turnover and/or adaptive modification may also contribute to the loss of sequence conservation. PMID:15062796

  17. The clustering of galaxies and galaxy clusters: constraints on primordial non-Gaussianity from future wide-field surveys

    NASA Astrophysics Data System (ADS)

    Fedeli, C.; Carbone, C.; Moscardini, L.; Cimatti, A.

    2011-06-01

    We investigate the constraints on primordial non-Gaussianity with varied bispectrum shapes that can be derived from the power spectrum of galaxies and clusters of galaxies detected in future wide field optical/near-infrared surveys. Having in mind the proposed ESA space mission Euclid as a specific example, we combine the spatial distribution of spectroscopically selected galaxies with that of weak lensing selected clusters. We use the physically motivated halo model in order to represent the correlation function of arbitrary tracers of the large-scale structure in the Universe. As naively expected, we find that galaxies are much more effective in jointly constrain the level of primordial non-Gaussianity fNL and the amplitude of the matter power spectrum σ8 than clusters of galaxies, due to the much lower abundance of the latter that is not adequately compensated by the larger effect on the power spectrum. Nevertheless, combination of the galaxy power spectrum with the cluster-galaxy cross-spectrum can decrease the error on the determination of fNL by up to a factor of ˜2. This decrement is particularly evident for the less studied non-Gaussian bispectrum shapes, the so-called enfolded and the orthogonal ones. Setting constraints on these models can shed new light on various aspects of the physics of the early Universe, and hence it is of extreme importance. By combining the power spectra of clusters and galaxies with the cluster-galaxy cross-spectrum we find constraints on primordial non-Gaussianity of the order ΔfNL˜ a few, competitive and possibly superior to future cosmic microwave background experiments.

  18. QTL clustering as a mechanism for rapid multi-trait evolution.

    PubMed

    Yoshizawa, Masato; O'Quin, Kelly E; Jeffery, William R

    2013-07-01

    Cave-dwelling animals exhibit remarkable convergence in multiple cave-related traits, yet the genetic mechanisms responsible for the evolution and integration of many such traits remain unclear. Astyanax mexicanus is a model cave-dwelling fish with sighted surface-dwelling (surface fish) and blind cave-dwelling (cavefish) forms. Using a genetic cross between these morphs, we discovered significant correlations among several cave-related traits, including reduced eyes, increased superficial neuromast receptors located within the eye orbit (EO SN) and a vibration-attraction behavior (VAB) that facilitates foraging in darkness. Furthermore, we discovered that the quantitative trait loci (QTL) underlying these traits are clustered within the Astyanax genome. Following an ablation experiment that demonstrated that the EO SN contribute to VAB, we concluded that the adaptive evolution of VAB and EO SN has likely contributed to eye loss in cavefish. In this addendum, we further discuss the possible role of multi-trait QTL clustering in facilitating rapid adaptation. PMID:23956812

  19. The WARPS Survey - VIII. Evolution of the galaxy cluster X-ray Luminosity Function

    NASA Astrophysics Data System (ADS)

    Koens, L. A.; Maughan, B. J.; Jones, L. R.; Ebeling, H.; Horner, D. J.; Perlman, E. S.; Phillipps, S.; Scharf, C. A.

    2013-11-01

    We present measurements of the galaxy cluster X-ray Luminosity Function (XLF) from the Wide Angle ROSAT Pointed Survey (WARPS) and quantify its evolution. WARPS is a serendipitous survey of the central region of ROSAT pointed observations and was carried out in two phases (WARPS-I and WARPS-II). The results here are based on a final sample of 124 clusters, complete above a flux limit of 6.5 × 10-14 erg cm-2 s-1, with members out to redshift z ˜ 1.05, and a sky coverage of 70.9 deg2. We find significant evidence for negative evolution of the XLF, which complements the majority of X-ray cluster surveys. To quantify the suggested evolution, we perform a maximum likelihood analysis and conclude that the evolution is driven by a decreasing number density of high-luminosity clusters with redshift, while the bulk of the cluster population remains nearly unchanged out to redshift z ≈ 1.1, as expected in a low-density universe. The results are found to be insensitive to a variety of sources of systematic uncertainty that affect the measurement of the XLF and determination of the survey selection function. We perform a Bayesian analysis of the XLF to fully account for uncertainties in the local XLF on the measured evolution, and find that the detected evolution remains significant at the 95 per cent level. We observe a significant excess of clusters in the WARPS at 0.1 < z < 0.3 and LX ≈ 2 × 1043 erg s-1 compared with the reference low-redshift XLF, or our Bayesian fit to the WARPS data. We find that the excess cannot be explained by sample variance, or Eddington bias, and is unlikely to be due to problems with the survey selection function.

  20. A Survey of Distant Clusters of Galaxies Selected by X-Rays

    NASA Technical Reports Server (NTRS)

    McNamara, Brian

    1997-01-01

    I will discuss the results of a new survey of X-ray selected, distant clusters of galaxies that has been undertaken by our group at.CfA (Vikhlinin, McNamara, Forman, Jones). We have analyzed the inner 17.5 arcminute region of roughly 650 ROSAT PSPC images of high latitude fields to compile a complete, flux-limited sample of clusters with a mean flux limit roughly 20 times more sensitive than the Einstein Medium Sensitivity Survey. The goal of our survey, which presently contains 233 extended X-ray sources, is to study cluster evolution over cosmological timescales. We have obtained optical images for nearly all of the faintest sources using the 1.2 m telescope of the Fred L. Whipple Observatory, and when including POSS images of the brighter sources, we have nearly completed the identification of all of the extended sources. Roughly 80% of the sources were identified as clusters of galaxies. We have measured redshifts for 42 clusters using the MMT, and including additional measurements from the literature, roughly 70 clusters in our catalog have spectroscopic redshifts. Using CCD photometry and spectroscopic redshifts, we have determined a magnitude-redshift relation which will allow redshifts of the remaining clusters in our sample to be determined photometrically to within a delta z over z of roughly ten percent. I will discuss the Log(N)-Log(S) relation for our sample and compare it to other determinations. In addition, I will discuss the evolution of core radii of clusters.

  1. Embedded Clusters in the Large Magellanic Cloud Using the VISTA Magellanic Clouds Survey

    NASA Astrophysics Data System (ADS)

    Romita, Krista; Lada, Elizabeth; Cioni, Maria-Rosa

    2016-04-01

    We present initial results of the first large-scale survey of embedded star clusters in molecular clouds in the Large Magellanic Cloud (LMC) using near-infrared imaging from the Visible and Infrared Survey Telescope for Astronomy Magellanic Clouds Survey. We explored a ∼1.65 deg2 area of the LMC, which contains the well-known star-forming region 30 Doradus as well as ∼14% of the galaxy’s CO clouds, and identified 67 embedded cluster candidates, 45 of which are newly discovered as clusters. We have determined the sizes, luminosities, and masses for these embedded clusters, examined the star formation rates (SFRs) of their corresponding molecular clouds, and made a comparison between the LMC and the Milky Way. Our preliminary results indicate that embedded clusters in the LMC are generally larger, more luminous, and more massive than those in the local Milky Way. We also find that the surface densities of both embedded clusters and molecular clouds is ∼3 times higher than in our local environment, the embedded cluster mass surface density is ∼40 times higher, the SFR is ∼20 times higher, and the star formation efficiency is ∼10 times higher. Despite these differences, the SFRs of the LMC molecular clouds are consistent with the SFR scaling law presented in Lada et al. This consistency indicates that while the conditions of embedded cluster formation may vary between environments, the overall process within molecular clouds may be universal. Based on observations made with VISTA at the Paranal Observatory under program ID 179.B-2003.

  2. A survey of rapid sample return needs from Space Station Freedom and potential return systems

    NASA Technical Reports Server (NTRS)

    Mccandless, Ronald S.; Siegel, Bette; Charlton, Kevin

    1991-01-01

    Results are presented of a survey conducted among potential users of the life sciences and material sciences facilities at the Space Station Freedom (SSF) to determine the need for a special rapid sample return (RSR) mission to bring the experimental samples from the Space Station Freedom (SSF) to earth between the Space Shuttle visits. The results of the survey show that, while some experimental objectives would benefit from the RSR capability, other available cost- and mission-effective means could be used instead of the RSR proposed. Potential vehicles for transporting samples from the SSF to earth are examined in the context of the survey results.

  3. An IUE survey of the Hyades star cluster

    NASA Technical Reports Server (NTRS)

    Zolcinski, M. C.; Kay, L.; Antiochos, S.; Stern, R.; Walker, A. B. C.

    1982-01-01

    To date 11 of the brightest X-Ray stars (F-K dwarfs) in the Hyades have been observed with the IUE satellite with the short wavelength spectrograph. The IUE results and the X-Ray observations from the Hyades survey with the Einstein Observatory were combined. The differential emission measure function was estimated for each of the 7 stars which showed evidence of emission lines. Constraints on stellar atmospheric parameters (chromospheric pressure, coronal temperature and filling factor were derived. The implications of these results in the context of loop models for the corona and transition region (TR) of these stars are discussed.

  4. Gravitational redshift of galaxies in clusters from the sloan digital sky survey and the Baryon Oscillation spectroscopic survey.

    PubMed

    Sadeh, Iftach; Feng, Low Lerh; Lahav, Ofer

    2015-02-20

    The gravitational redshift effect allows one to directly probe the gravitational potential in clusters of galaxies. Following up on Wojtak et al. [Nature (London) 477, 567 (2011)], we present a new measurement. We take advantage of new data from the tenth data release of the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey. We compare the spectroscopic redshift of the brightest cluster galaxies (BCGs) with that of galaxies at the outskirts of clusters, using a sample with an average cluster mass of 1014M⊙. We find that these galaxies have an average relative redshift of -11  km/s compared with that of BCGs, with a standard deviation of +7 and -5  km/s. Our measurement is consistent with that of Wojtak et al. [Nature (London) 477, 567 (2011)]. However, our derived standard deviation is larger, as we take into account various systematic effects, beyond the size of the data set. The result is in good agreement with the predictions from general relativity. PMID:25763947

  5. COMPARING DENSE GALAXY CLUSTER REDSHIFT SURVEYS WITH WEAK-LENSING MAPS

    SciTech Connect

    Hwang, Ho Seong; Geller, Margaret J.; Zahid, H. Jabran; Diaferio, Antonaldo; Rines, Kenneth J. E-mail: mgeller@cfa.harvard.edu E-mail: diaferio@ph.unito.it

    2014-12-20

    We use dense redshift surveys of nine galaxy clusters at z ∼ 0.2 to compare the galaxy distribution in each system with the projected matter distribution from weak lensing. By combining 2087 new MMT/Hectospec redshifts and the data in the literature, we construct spectroscopic samples within the region of weak-lensing maps of high (70%-89%) and uniform completeness. With these dense redshift surveys, we construct galaxy number density maps using several galaxy subsamples. The shape of the main cluster concentration in the weak-lensing maps is similar to the global morphology of the number density maps based on cluster members alone, mainly dominated by red members. We cross-correlate the galaxy number density maps with the weak-lensing maps. The cross-correlation signal when we include foreground and background galaxies at 0.5z {sub cl} < z < 2z {sub cl} is 10%-23% larger than for cluster members alone at the cluster virial radius. The excess can be as high as 30% depending on the cluster. Cross-correlating the galaxy number density and weak-lensing maps suggests that superimposed structures close to the cluster in redshift space contribute more significantly to the excess cross-correlation signal than unrelated large-scale structure along the line of sight. Interestingly, the weak-lensing mass profiles are not well constrained for the clusters with the largest cross-correlation signal excesses (>20% for A383, A689, and A750). The fractional excess in the cross-correlation signal including foreground and background structures could be a useful proxy for assessing the reliability of weak-lensing cluster mass estimates.

  6. The San Pedro Mártir Open Cluster Survey: Progress, Techniques, Preliminary Results

    NASA Astrophysics Data System (ADS)

    Schuster, W.; Michel, R.; Dias, W.; Tapia-Peralta, T.; Vázquez, R.; Macfarland, J.; Chavarría, C.; Santos, C.; Moitinho, A.

    2007-05-01

    A CCD UBVRI survey of northern open clusters is being undertaken at San Pedro Mártir, Mexico, and performed using always the same instrumental setup (telescope, CCD, filters), reduction methods, and system of standards (Landolt). To date more than 300 clusters (mostly unstudied previously) have been observed, and about half the data reduced using aperture-photometry and PSF techniques. Our analysis procedures are being refined by studying in detail a small subset of these clusters. For example, the heavily reddened clusters Be80 and Be95 are being examined in the color-color diagrams: (B-V,U-B) and (B-V,R-I) to better understand the problems of curvature and variable reddening. For clusters for which our U data reaches the F-type stars, such as NGC2192 and NGC7296, techniques are being examined for estimating both the reddening E(B-V) and metallicity [Fe/H] via the use of the (U-B) excess. If the clusters also have "red clump" stars, such as NGC1798 and Do02, these procedures can be iterated between the clump and main sequence stars to establish even better the values of E(B-V) and [Fe/H]. Finally, color-magnitude diagrams, such as (B-V,V) and (V-I,V), are being employed together with the Schmidt-Kaler colors and Padova isochrones to obtain distances and ages for these clusters. A java-based computer program is being developed to help in the visualization and analysis of these photometric data. This system is capable of displaying each cluster simultaneously in different color-color and color-magnitude diagrams and has an interactive way to identify a star, or group of stars, in one diagram and to see were it falls in the other diagrams, facilitating the elimination of field stars and the apperception of cluster features. This program is capable of displaying up to 16 different diagrams for one cluster and processing up to 20 clusters at the same time. Our aims are the following: (1) a common UBVRI photometric scale for open clusters, (2) an atlas of color

  7. The XMM-BCS galaxy cluster survey: I. The X-ray selected cluster catalog from the initial 6 deg$^2$

    SciTech Connect

    Suhada, R.; Song, J.; Bohringer, H.; Mohr, J.J.; Chon, G.; Finoguenov, A.; Fassbender, R.; Desai, S.; Armstrong, R.; Zenteno, A.; Barkhouse, W.A.; /North Dakota U. /Paris, Inst. Astrophys.

    2011-11-01

    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 0.47 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

  8. Observation of the Coma cluster of galaxies with ROSAT during the all-sky survey

    NASA Technical Reports Server (NTRS)

    Briel, U. G.; Henry, J. P.; Boehringer, H.

    1992-01-01

    The Coma cluster of galaxies was observed with the position sensitive proportional counter (PSPC) during the ROSAT all sky survey. We find evidence for substructure in this cluster. Diffuse X-ray emission is detected from the regions of the NGC 4839 and 4911 subgroups at 6 percent and 1 percent of the total cluster emission respectively. There may be emission associated with the NGC 4874 and 4889 subgroups as well. The NGC 4839 group appears to be in the process of merging with the cluster. These X-ray data show that at least some of the groups previously found in projection are in fact physical objects possessing potential wells deep enough to trap their own X-ray gas. Because of the unlimited field of view of the all sky survey and the low background of the PSPC, we were able to measure the azimuthally averaged surface brightness of Coma out to approximately 100 arcmin, twice as far as was previously possible. Given the validity of our mass models, these new X-ray data imply that within 5/h(50) Mpc the binding mass of the Coma cluster is 1.8 +/- 0.6 x 10 exp 15/h(50) solar mass, and the fraction of cluster mass contained in hot gas is 0.30 +/- 0.14h(50) exp -3/2. Furthermore, the binding mass is more centrally concentrated than is the X-ray gas.

  9. SUPERDENSE MASSIVE GALAXIES IN THE ESO DISTANT CLUSTER SURVEY (EDisCS)

    SciTech Connect

    Valentinuzzi, T.; D'onofrio, M.; Vulcani, B.; Poggianti, B. M.; Fritz, J.; Moretti, A.; Saglia, R. P.; Aragon-Salamanca, A.; Simard, L.; Sanchez-Blazquez, P.; Cava, A.; Couch, W. J.

    2010-09-20

    We find a significant number of massive and compact galaxies in clusters from the ESO Distant Clusters Survey (EDisCS) at 0.4 < z < 1. They have similar stellar masses, ages, sizes, and axial ratios to local z {approx} 0.04 compact galaxies in WIde field Nearby Galaxy clusters Survey (WINGS) clusters, and to z = 1.4-2 massive and passive galaxies found in the general field. If non-brightest cluster galaxies of all densities, morphologies, and spectral types are considered, the median size of EDisCS galaxies is only a factor 1.18 smaller than in WINGS. We show that for morphologically selected samples, the morphological evolution taking place in a significant fraction of galaxies during the last Gyr may introduce an apparent, spurious evolution of size with redshift, which is actually due to intrinsic differences in the selected samples. We conclude that the median mass-size relation of cluster galaxies does not evolve significantly from z {approx} 0.7 to z {approx} 0.04. In contrast, the masses and sizes of BCGs and galaxies with M {sub *}>4 x 10{sup 11} M {sub sun} have significantly increased by a factor of 2 and 4, respectively, confirming the results of a number of recent works on the subject. Our findings show that progenitor bias effects play an important role in the size-growth paradigm of massive and passive galaxies.

  10. The XXL Survey. III. Luminosity-temperature relation of the bright cluster sample

    NASA Astrophysics Data System (ADS)

    Giles, P. A.; Maughan, B. J.; Pacaud, F.; Lieu, M.; Clerc, N.; Pierre, M.; Adami, C.; Chiappetti, L.; Démoclés, J.; Ettori, S.; Le Févre, J. P.; Ponman, T.; Sadibekova, T.; Smith, G. P.; Willis, J. P.; Ziparo, F.

    2016-06-01

    Context. The XXL Survey is the largest homogeneous survey carried out with XMM-Newton. Covering an area of 50 deg2, the survey contains several hundred galaxy clusters out to a redshift of ~2 above an X-ray flux limit of ~5 × 10-15 erg cm-2 s-1. This paper belongs to the first series of XXL papers focusing on the bright cluster sample. Aims: We investigate the luminosity-temperature (LT) relation for the brightest clusters detected in the XXL Survey, taking fully into account the selection biases. We investigate the form of the LT relation, placing constraints on its evolution. Methods: We have classified the 100 brightest clusters in the XXL Survey based on their measured X-ray flux. These 100 clusters have been analysed to determine their luminosity and temperature to evaluate the LT relation. We used three methods to fit the form of the LT relation, with two of these methods providing a prescription to fully take into account the selection effects of the survey. We measure the evolution of the LT relation internally using the broad redshift range of the sample. Results: Taking fully into account selection effects, we find a slope of the bolometric LT relation of BLT = 3.08 ± 0.15, steeper than the self-similar expectation (BLT = 2). Our best-fit result for the evolution factor is E(z)1.64 ± 0.77, fully consistent with "strong self-similar" evolution where clusters scale self-similarly with both mass and redshift. However, this result is marginally stronger than "weak self-similar" evolution, where clusters scale with redshift alone. We investigate the sensitivity of our results to the assumptions made in our fitting model, finding that using an external LT relation as a low-z baseline can have a profound effect on the measured evolution. However, more clusters are needed in order to break the degeneracy between the choice of likelihood model and mass-temperature relation on the derived evolution. Based on observations obtained with XMM-Newton, an ESA science

  11. Clustering of ROSAT All-Sky Survey AGNs Through Cross-Correlation Functions

    NASA Astrophysics Data System (ADS)

    Krumpe, Mirko; Miyaji, Takamitsu; Coil, Alison

    2010-07-01

    We investigate the clustering propertiesof ~1550 low-redshift broad-line AGNs detected in the ROSAT All-Sky Survey (RASS) through a cross-correlation function (CCF) with ~46000 Luminous Red Galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS). Using this approach, we avoid small-number statistics and systematic errors caused by the variation of the Galactic absorption compared to a direct measurement of the AGN auto-correlation function (ACF). We compute the ACF of low-z RASS-AGN based on the CCF for the total X-ray sample ( = 0.25) and found a correlation length of r0 = 4.3-0.4+0.4 h-1 Mpc. Furthermore, we discovered an X-ray luminosity dependence of the clustering signal, i.e. high luminosity AGN cluster stronger than low luminosity AGN. We have also applied a Halo Occupation Distribution (HOD) model directly to our AGN-LRG CCF.

  12. The Gaia-ESO Survey: Stellar content and elemental abundances in the massive cluster NGC 6705

    NASA Astrophysics Data System (ADS)

    Cantat-Gaudin, T.; Vallenari, A.; Zaggia, S.; Bragaglia, A.; Sordo, R.; Drew, J. E.; Eisloeffel, J.; Farnhill, H. J.; Gonzalez-Solares, E.; Greimel, R.; Irwin, M. J.; Kupcu-Yoldas, A.; Jordi, C.; Blomme, R.; Sampedro, L.; Costado, M. T.; Alfaro, E.; Smiljanic, R.; Magrini, L.; Donati, P.; Friel, E. D.; Jacobson, H.; Abbas, U.; Hatzidimitriou, D.; Spagna, A.; Vecchiato, A.; Balaguer-Nunez, L.; Lardo, C.; Tosi, M.; Pancino, E.; Klutsch, A.; Tautvaisiene, G.; Drazdauskas, A.; Puzeras, E.; Jiménez-Esteban, F.; Maiorca, E.; Geisler, D.; San Roman, I.; Villanova, S.; Gilmore, G.; Randich, S.; Bensby, T.; Flaccomio, E.; Lanzafame, A.; Recio-Blanco, A.; Damiani, F.; Hourihane, A.; Jofré, P.; de Laverny, P.; Masseron, T.; Morbidelli, L.; Prisinzano, L.; Sacco, G. G.; Sbordone, L.; Worley, C. C.

    2014-09-01

    Context. Chemically inhomogeneous populations are observed in most globular clusters, but not in open clusters. Cluster mass seems to play a key role in the existence of multiple populations. Aims: Studying the chemical homogeneity of the most massive open clusters is needed to better understand the mechanism of their formation and determine the mass limit under which clusters cannot host multiple populations. Here we studied NGC 6705, which is a young and massive open cluster located towards the inner region of the Milky Way. This cluster is located inside the solar circle. This makes it an important tracer of the inner disk abundance gradient. Methods: This study makes use of BVI and ri photometry and comparisons with theoretical isochrones to derive the age of NGC 6705. We study the density profile of the cluster and the mass function to infer the cluster mass. Based on abundances of the chemical elements distributed in the first internal data release of the Gaia-ESO Survey, we study elemental ratios and the chemical homogeneity of the red clump stars. Radial velocities enable us to study the rotation and internal kinematics of the cluster. Results: The estimated ages range from 250 to 316 Myr, depending on the adopted stellar model. Luminosity profiles and mass functions show strong signs of mass segregation. We derive the mass of the cluster from its luminosity function and from the kinematics, finding values between 3700 M⊙ and 11 000 M⊙. After selecting the cluster members from their radial velocities, we obtain a metallicity of [Fe/H] = 0.10 ± 0.06 based on 21 candidate members. Moreover, NGC 6705 shows no sign of the typical correlations or anti-correlations between Al, Mg, Si, and Na, which are expected in multiple populations. This is consistent with our cluster mass estimate, which is lower than the required mass limit proposed in the literature to develop multiple populations. Based on the data obtained at ESO telescopes under programme 188.B-3002

  13. Measuring the X-ray luminosities of SDSS DR7 clusters from ROSAT All Sky Survey

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Yang, Xiaohu; Shen, Shiyin; Mo, H. J.; van den Bosch, Frank C.; Luo, Wentao; Wang, Yu; Lau, Erwin T.; Wang, Q. D.; Kang, Xi; Li, Ran

    2014-03-01

    We use ROSAT All Sky Survey broad-band X-ray images and the optical clusters identified from Sloan Digital Sky Survey Data Release 7 to estimate the X-ray luminosities around ˜65 000 candidate clusters with masses ≳ 1013 h- 1 M⊙ based on an optical to X-ray (OTX) code we develop. We obtain a catalogue with X-ray luminosity for each cluster. This catalogue contains 817 clusters (473 at redshift z ≤ 0.12) with signal-to-noise ratio >3 in X-ray detection. We find about 65 per cent of these X-ray clusters have their most massive member located near the X-ray flux peak; for the rest 35 per cent, the most massive galaxy is separated from the X-ray peak, with the separation following a distribution expected from a Navarro-Frenk-White profile. We investigate a number of correlations between the optical and X-ray properties of these X-ray clusters, and find that the cluster X-ray luminosity is correlated with the stellar mass (luminosity) of the clusters, as well as with the stellar mass (luminosity) of the central galaxy and the mass of the halo, but the scatter in these correlations is large. Comparing the properties of X-ray clusters of similar halo masses but having different X-ray luminosities, we find that massive haloes with masses ≳ 1014 h- 1 M⊙ contain a larger fraction of red satellite galaxies when they are brighter in X-ray. An opposite trend is found in central galaxies in relative low-mass haloes with masses ≲ 1014 h- 1 M⊙ where X-ray brighter clusters have smaller fraction of red central galaxies. Clusters with masses ≳ 1014 h- 1 M⊙ that are strong X-ray emitters contain many more low-mass satellite galaxies than weak X-ray emitters. These results are also confirmed by checking X-ray clusters of similar X-ray luminosities but having different characteristic stellar masses. A cluster catalogue containing the optical properties of member galaxies and the X-ray luminosity is available at http://gax.shao.ac.cn/data/Group.html.

  14. OT1_eegami_4: SPIRE Snapshot Survey of Massive Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Egami, E.

    2010-07-01

    For deep imaging longward of 100 um, confusion noise sets the fundamental sensitivity limits achievable with Herschel, and these limits cannot be improved by integrating longer. To penetrate through this confusion limit and detect faint high-redshift galaxies, gravitational lensing by massive galaxy clusters offers a very powerful and yet cheap solution. For this reason, we are currently conducting a PACS/SPIRE imaging survey of ~40 massive lensing clusters as one of the Herschel Key Programs, "The Herschel Lensing Survey" (PI: Egami, 292.3 hrs). Although this program is producing many exciting results as reported in our 5 Herschel special-issue papers, one thing is becoming clear: it is extremely difficult to find lensed galaxies that are bright enough (> 200 mJy in SPIRE bands) to perform spectroscopy with PACS/SPIRE. This disappointment, however, was quickly overcome by the serendipitous discovery of an exceptionally bright (~500 mJy@350 um) z=2.3 galaxy lensed by a massive cluster at z=0.325. This discovery suggests that if we survey a large enough cluster sample, we will find similarly bright lensed sources that make all kinds of exciting follow-up observations possible. Here, we propose to conduct such a survey by taking advantage of the Millennium Cluster Sample constructed from the ROSAT All-Sky Survey with many years of extensive follow-ups. More specifically, we will conduct a SPIRE snapshot survey of 279 X-ray-selected clusters. SPIRE's great sensitivity and observing efficiency means that we can complete this program in only 27 hours while achieving a nearly confusion-limited sensitivity of 10 mJy (1 sigma). Such a depth will allow all kinds of secondary science projects as well. Although SPIRE wide-area surveys like H-ATLAS will also discover many bright lensed galaxies, these sources are mostly lensed by galaxies and not clusters, which makes our approach an economic alternative to investigate a different type of lensed systems.

  15. A multibeam HI survey of the Virgo cluster - two isolated HI clouds?

    NASA Astrophysics Data System (ADS)

    Davies, J.; Minchin, R.; Sabatini, S.; van Driel, W.; Baes, M.; Boyce, P.; de Blok, W. J. G.; Disney, M.; Evans, Rh.; Kilborn, V.; Lang, R.; Linder, S.; Roberts, S.; Smith, R.

    2004-04-01

    We have carried out a fully sampled large area (4°× 8°) 21-cm HI line survey of part of the Virgo cluster using the Jodrell Bank multibeam instrument. The survey has a sensitivity some three times better than the standard HIJASS (HI Jodrell All Sky Survey) and HIPASS (HI Parkes All Sky Survey) surveys. We detect 31 galaxies, 27 of which are well-known cluster members. The four new detections have been confirmed in the HIPASS data and by follow-up Jodrell Bank pointed observations. One object lies behind M86, but the other three have no obvious optical counterparts upon inspection of the digital sky survey fields. These three objects were mapped at Arecibo with a smaller 3.6-arcmin half power beam width (HPBW) and a four times better sensitivity than the Jodrell Bank data, which allow an improved determination of the dimensions and location of two of the objects, but surprisingly failed to detect the third. The two objects are resolved by the Arecibo beam, giving them a size far larger than any optical images in the nearby field. To our mass limit of 5 × 107(Δv/50 km s-1) Msolar and column density limit of 3 × 1018(Δv/50 km s-1) atom cm-2, these new detections represent only about 2 per cent of the cluster atomic hydrogen mass. Our observations indicate that the HI mass function of the cluster turns down at the low-mass end, making it very different to the field galaxy HI mass function. This is quite different to the Virgo cluster optical luminosity function, which is much steeper than that in the general field. Many of the sample galaxies are relatively gas-poor compared with HI selected samples of field galaxies, confirming the `anaemic spirals' view of Virgo cluster late-type galaxies. The velocity distribution of the HI detected galaxies is also very different to that of the cluster as a whole. There are relatively more high-velocity galaxies in the HI sample, suggesting that they form part of a currently infalling population. The HI sample with optical

  16. XMM-Newton Observations of the DLS Shear-Selected Cluster Survey

    NASA Technical Reports Server (NTRS)

    DellAntonio, Ian

    2005-01-01

    The goal of this project continues to be to test the selection effects in cluster surveys by investigating the X-ray properties of the first shear-selected sample of galaxy clusters, the Deep Lens Survey (DLS). Because lensing signal is only sensitive to mass (albeit with projection effects), lensing signal can be used to select a sample that is independent of its X-ray properties. If a lensing-selected sample has very different X-ray properties from an X-ray selected sample, it would have important consequences for evolutionary studies based on existing cluster samples was aimed at refining the lensing-selected sample as part of this continuing study The grant supported a KPNO run to obtain data on another region of the sky to extend the cluster sample, and also the purchase of a disk array for archiving the optical mosaic data (Two terabytes worth) from which the lensing maps are derived As a result of the grant, we have extended the lensing cluster sample to another 4-square degree patch of the sky, adding another three clusters to our sample to be observed While the sample of X-ray observed clusters is too small to derive a firm conclusion yet, our preliminary finding is that the X-ray properties of the observed sample do not differ from those of X-ray selected surveys A paper discussing the first results has been published, and a second paper on the mass differences is still in preparation (with J Hughes as first author)

  17. The Wide-Field Nearby Galaxy-Cluster Survey (WINGS) and Its Extension OMEGAWINGS

    NASA Astrophysics Data System (ADS)

    Poggianti, B. M.; Fasano, G.; Bettoni, D.; Cava, A.; Couch, W.; D'Onofrio, M.; Dressler, A.; Fritz, J.; Kjaergaard, P.; Gullieuszik, M.; Moles, M.; Moretti, A.; Omizzolo, A.; Paccagnella, A.; Varela, J.; Vulcani, B.

    WINGS is a wide-field multi-wavelength survey of 76 X-ray selected clusters at low redshift. The WINGS database has been used for a variety of cluster and cluster galaxy studies, investigating galaxy star formation, morphologies, structure, stellar mass functions and other properties. We present the recent wider-field extension of WINGS, OMEGAWINGS, conducted with OmegaCAM@VST and AAOmega@AAT. We show two of our latest results regarding jellyfish galaxies and galaxy sizes. OMEGAWINGS has allowed the first systematic search of galaxies with signs of ongoing ram pressure stripping (jellyfishes), yielding a catalog of ˜ 240 galaxies in 41 clusters. We discuss the first results obtained from this sample and the prospects for integral field data. Finally, we summarize our results regarding the discovery of compact massive galaxies at low redshift, their properties, dependence on environment and the implications for the evolution of galaxy sizes from high- to low-z.

  18. The evolution of the brightest cluster galaxies since z ~ 1 from the ESO Distant Cluster Survey (EDisCS)

    NASA Astrophysics Data System (ADS)

    Whiley, I. M.; Aragón-Salamanca, A.; De Lucia, G.; von der Linden, A.; Bamford, S. P.; Best, P.; Bremer, M. N.; Jablonka, P.; Johnson, O.; Milvang-Jensen, B.; Noll, S.; Poggianti, B. M.; Rudnick, G.; Saglia, R.; White, S.; Zaritsky, D.

    2008-07-01

    We present K-band data for the brightest cluster galaxies (BCGs) from the ESO Distant Cluster Survey (EDisCS). These data are combined with the photometry published by Aragón-Salamanca, Baugh & Kauffmann and a low-redshift comparison sample built from the BCG catalogue of von der Linden et al. BCG luminosities are measured inside a metric circular aperture with 37kpc diameter. In agreement with previous studies, we find that the K-band Hubble diagram for BCGs exhibits very low scatter (~0.35) over a redshift range of 0 < z < 1. The colour and rest-frame K-band luminosity evolution of the BCGs are in good agreement with population synthesis models of stellar populations which formed at z > 2 and evolved passively thereafter. In contrast with some previous studies, we do not detect any significant change in the stellar mass of the BCG since z ~ 1. These results do not seem to depend on the velocity dispersion of the parent cluster. We also find that there is a correlation between the 1D velocity dispersion of the clusters (σcl) and the K-band luminosity of the BCGs (after correcting for passive-evolution). The clusters with large velocity dispersions, and therefore masses, tend to have brighter BCGs, i.e. BCGs with larger stellar masses. This dependency, although significant, is relatively weak: the stellar mass of the BCGs changes only by ~70 per cent over a two order of magnitude range in cluster mass. Furthermore, this dependency does not change significantly with redshift. We have compared our observational results with the hierarchical galaxy formation and evolution model predictions of De Lucia & Blaizot. We find that the models predict colours which are in reasonable agreement with the observations because the growth in stellar mass is dominated by the accretion of old stars. However, the stellar mass in the model BCGs grows by a factor of 3-4 since z = 1, a growth rate which seems to be ruled out by the observations. The models predict a dependency between

  19. X-ray Properties of Clusters from the Palomar Deep Survey

    NASA Astrophysics Data System (ADS)

    Holden, B. H.; Nichol, B. C.; Romer, A. K.; Ulmer, M. P.

    1996-05-01

    Twenty of the 79 z>0.2 distant, optically selected, cluster candidates in the Palomar Deep Cluster Survey (Postman et al. 1996) were serendipitously observed by the ROSAT satellite. We have reduced the three PSPC pointings that overlapped Postman et al. (1996) fields using the Snowden et al. (1994) Extended X-ray Analysis Software and a wavelet analysis source detection algorithm. We derive count rates for the cluster candidates inside a metric aperture defined by the estimate redshift quoted in Postman et al. (1996). We find all 20 clusters observed by the PSPC to be X-ray faint; only 4 were detected at >3sigma . The luminosities derived from the measured/upper-limit count rates are significantly lower than those predicted from the richness vs luminosity distribution derived for X-ray selected clusters (Edge & Stewart 1991). This discrepancy cannot be wholly attributed to projection effects; according to Postman et al. (1996) less than 30% of their objects are ``phantom clusters''. We will present evidence to support our conclusion that optically selected clusters are younger and less evolved than their X-ray selected counterparts.

  20. THE SNAPSHOT HUBBLE U-BAND CLUSTER SURVEY (SHUCS). I. SURVEY DESCRIPTION AND FIRST APPLICATION TO THE MIXED STAR CLUSTER POPULATION OF NGC 4041

    SciTech Connect

    Konstantopoulos, I. S.; Smith, L. J.; Adamo, A.; Silva-Villa, E.; Gallagher, J. S.; Ryon, J. E.; Bastian, N.; Westmoquette, M. S.; Zackrisson, E.; Larsen, S. S.; Charlton, J. C.

    2013-05-15

    We present the Snapshot Hubble U-band Cluster Survey (SHUCS), a project aimed at characterizing the star cluster populations of 10 nearby galaxies (d < 23 Mpc, half within Almost-Equal-To 12 Mpc) through new F336W (U-band equivalent) imaging from Wide Field Camera 3, and archival BVI-equivalent data with the Hubble Space Telescope. Completing the UBVI baseline reduces the age-extinction degeneracy of optical colors, thus enabling the measurement of reliable ages and masses for the thousands of clusters covered by our survey. The sample consists chiefly of face-on spiral galaxies at low inclination, in various degrees of isolation (isolated, in group, merging), and includes two active galactic nucleus hosts. This first paper outlines the survey itself, the observational datasets, the analysis methods, and presents a proof-of-concept study of the large-scale properties and star cluster population of NGC 4041, a massive SAbc galaxy at a distance of Almost-Equal-To 23 Mpc, and part of a small grouping of six giant members. We resolve two structural components with distinct stellar populations, a morphology more akin to merging and interacting systems. We also find strong evidence of a truncated, Schechter-type mass function, and a similarly segmented luminosity function. These results indicate that binning must erase much of the substructure present in the mass and luminosity functions, and might account for the conflicting reports on the intrinsic shape of these functions in the literature. We also note a tidal feature in the outskirts of the galaxy in Galaxy Evolution Explorer UV imaging, and follow it up with a comprehensive multi-wavelength study of NGC 4041 and its parent group. We deduce a minor merger as a likely cause of its segmented structure and the observed pattern of a radially decreasing star formation rate. We propose that combining the study of star cluster populations with broadband metrics is not only advantageous, but often easily achievable thorough

  1. Searching for galaxy clusters in X-ray and optical sky surveys

    NASA Astrophysics Data System (ADS)

    Boschin, W.

    2003-04-01

    The last decade has seen a poderous progress in the research of galaxy clusters. In fact, the application of modern technologies (CCDs, optical fibers, large aperture optical and X-ray telescopes, etc.) in the field of astrophysical observations has allowed fundamental studies of nearby galaxy clusters, both of the optical component of such objects, i.e. galaxies, and the X-ray emitting intracluster gas. Moreover, systematic searches of these objects done by new generation optical and X-ray telescopes have produced valuable samples of medium-distant clusters, helping us to shed light on the evolution of their physical properties (abundance, mass, temperature, etc.), with particular reference to the distribution functions of such quantities. In particular, the cluster abundance distribution in function of redshift is very important since it is strictly connected to the cosmological parameters. From these consideration it is clear that the search for galaxy systems at different redshifts is a fundamental task in modern observational astrophysics. In this work I discuss the topic of searching for galaxy clusters both in X-ray surveys and in optical data. In particular, the main result is the building of a new galaxy cluster catalog based on a serendipitous search in Chandra X-ray archival data. The first chapter describes the general properties of galaxy systems with emphasis on their scientific relevance and the methods used to identify them in the sky. In the second chapter I describe the Chandra X-ray observatory and explain why it is a good instrument to detect clusters. In chapter three I present the characteristics of my survey, the reduction of data, the technique of detection of X-ray sources and the catalog of detected clusters. By computing the sky coverage of the survey I also present a first determination of the cluster cumulative log N-log S relation and show that it is in agreement with results from previous deep ROSAT-based surveys. Finally, in chapter

  2. Energetic particle sounding of the magnetopause: A contribution by Cluster/RAPID

    NASA Astrophysics Data System (ADS)

    Zong, Q.-G.; Fritz, T. A.; Spence, H.; Oksavik, K.; Pu, Z.-Y.; Korth, A.; Daly, P. W.

    2004-04-01

    In this paper we present new results using Cluster/Research with Adaptive Particle Imaging Detectors (RAPID) energetic particle observations to remotely sound the high-latitude magnetopause in three dimensions. We demonstrate that energetic particle flux variations in the vicinity of the magnetopause (inside the magnetosphere) are mainly modulated by the absorbing magnetopause during quiet geomagnetic conditions. Less than two gyro radii from an absorbing boundary a trapped particle distribution becomes nongyrotropic, as particles start to encounter the boundary. Knowing the magnetic field and the particle mass and energy, the direction and distance to the magnetopause can be derived by examining the azimuthal distribution of locally mirroring particles. Combining observations from three nearby spacecraft gives a three-dimensional, local picture of the magnetopause surface. We exploit anisotropic ion distributions to determine magnetopause distances, orientations, and structures in the interval from 1320 to 1420 UT on 14 January 2001 for the three Cluster spacecraft (Rumba, Samba, and Tango) located on the duskside (at ˜1700 MLT) high-latitude region. The results clearly illustrate that the magnetopause ion sounding technique as proposed by [1979], [1982], and [2000] can be used to remotely study the three-dimensional orientation and location of the magnetopause surface and the gradient variation of the plasma parameters. Intercomparison between energetic particle sounding distance and simultaneous plasma and magnetic field measurements suggests that solar wind plasma can penetrate more than ≈1000 km deeper than the trapping boundary. The fluxes of different ion species are proportional to the distance from the magnetopause, with a correlation coefficient of 0.7 to 0.8. The energetic proton flux gradient as a function of distance from the magnetosphere is about 100 particles cm-2 s-1 sr-1 per kilometer. In contrast, the solar wind plasma density is found to be

  3. Global survey of star clusters in the Milky Way. V. Integrated JHKS magnitudes and luminosity functions

    NASA Astrophysics Data System (ADS)

    Kharchenko, N. V.; Piskunov, A. E.; Schilbach, E.; Röser, S.; Scholz, R.-D.

    2016-01-01

    Aims: In this study we determine absolute integrated magnitudes in the J,H,KS passbands for Galactic star clusters from the Milky Way Star Clusters survey. In the wide solar neighbourhood, we derive the open cluster luminosity function (CLF) for different cluster ages. Methods: The integrated magnitudes are based on uniform cluster membership derived from the 2MAst catalogue (a merger of the PPMXL and 2MASS) and are computed by summing up the individual luminosities of the most reliable cluster members. We discuss two different techniques of constructing the CLF, a magnitude-limited and a distance-limited approach. Results: Absolute J,H,KS integrated magnitudes are obtained for 3061 open clusters, and 147 globular clusters. The integrated magnitudes and colours are accurate to about 0.8 and 0.2 mag, respectively. Based on the sample of open clusters we construct the general cluster luminosity function in the solar neighbourhood in the three passbands. In each passband the CLF shows a linear part covering a range of 6 to 7 mag at the bright end. The CLFs reach their maxima at an absolute magnitude of -2 mag, then drop by one order of magnitude. During cluster evolution, the CLF changes its slope within tight, but well-defined limits. The CLF of the youngest clusters has a steep slope of about 0.4 at bright magnitudes and a quasi-flat portion for faint clusters. For the oldest population, we find a flatter function with a slope of about 0.2. The CLFs at Galactocentric radii smaller than that of the solar circle differ from those in the direction of the Galactic anti-centre. The CLF in the inner area is flatter and the cluster surface density higher than the local one. In contrast, the CLF is somewhat steeper than the local one in the outer disk, and the surface density is lower. The corresponding catalogue of integrated magnitudes is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc

  4. The XXL Survey. II. The bright cluster sample: catalogue and luminosity function

    NASA Astrophysics Data System (ADS)

    Pacaud, F.; Clerc, N.; Giles, P. A.; Adami, C.; Sadibekova, T.; Pierre, M.; Maughan, B. J.; Lieu, M.; Le Fèvre, J. P.; Alis, S.; Altieri, B.; Ardila, F.; Baldry, I.; Benoist, C.; Birkinshaw, M.; Chiappetti, L.; Démoclès, J.; Eckert, D.; Evrard, A. E.; Faccioli, L.; Gastaldello, F.; Guennou, L.; Horellou, C.; Iovino, A.; Koulouridis, E.; Le Brun, V.; Lidman, C.; Liske, J.; Maurogordato, S.; Menanteau, F.; Owers, M.; Poggianti, B.; Pomarède, D.; Pompei, E.; Ponman, T. J.; Rapetti, D.; Reiprich, T. H.; Smith, G. P.; Tuffs, R.; Valageas, P.; Valtchanov, I.; Willis, J. P.; Ziparo, F.

    2016-06-01

    Context. The XXL Survey is the largest survey carried out by the XMM-Newton satellite and covers a total area of 50 square degrees distributed over two fields. It primarily aims at investigating the large-scale structures of the Universe using the distribution of galaxy clusters and active galactic nuclei as tracers of the matter distribution. The survey will ultimately uncover several hundreds of galaxy clusters out to a redshift of ~2 at a sensitivity of ~10-14 erg s-1 cm-2 in the [0.5-2] keV band. Aims: This article presents the XXL bright cluster sample, a subsample of 100 galaxy clusters selected from the full XXL catalogue by setting a lower limit of 3 × 10-14 erg s-1 cm-2 on the source flux within a 1' aperture. Methods: The selection function was estimated using a mixture of Monte Carlo simulations and analytical recipes that closely reproduce the source selection process. An extensive spectroscopic follow-up provided redshifts for 97 of the 100 clusters. We derived accurate X-ray parameters for all the sources. Scaling relations were self-consistently derived from the same sample in other publications of the series. On this basis, we study the number density, luminosity function, and spatial distribution of the sample. Results: The bright cluster sample consists of systems with masses between M500 = 7 × 1013 and 3 × 1014 M⊙, mostly located between z = 0.1 and 0.5. The observed sky density of clusters is slightly below the predictions from the WMAP9 model, and significantly below the prediction from the Planck 2015 cosmology. In general, within the current uncertainties of the cluster mass calibration, models with higher values of σ8 and/or ΩM appear more difficult to accommodate. We provide tight constraints on the cluster differential luminosity function and find no hint of evolution out to z ~ 1. We also find strong evidence for the presence of large-scale structures in the XXL bright cluster sample and identify five new superclusters. Based on

  5. The Gaia-ESO Survey: Stellar radii in the young open clusters NGC 2264, NGC 2547, and NGC 2516

    NASA Astrophysics Data System (ADS)

    Jackson, R. J.; Jeffries, R. D.; Randich, S.; Bragaglia, A.; Carraro, G.; Costado, M. T.; Flaccomio, E.; Lanzafame, A. C.; Lardo, C.; Monaco, L.; Morbidelli, L.; Smiljanic, R.; Zaggia, S.

    2016-02-01

    Context. Rapidly rotating, low-mass members of eclipsing binary systems have measured radii that are significantly larger than predicted by standard evolutionary models. It has been proposed that magnetic activity is responsible for this radius inflation. Aims: By estimating the radii of low-mass stars in three young clusters (NGC 2264, NGC 2547, NGC 2516, with ages of ~5, ~35 and ~140 Myr respectively), we aim to establish whether similar radius inflation is seen in single, magnetically active stars. Methods: We use radial velocities from the Gaia-ESO Survey (GES) and published photometry to establish cluster membership and then combine GES measurements of projected equatorial velocities with published rotation periods to estimate the average radii for groups of fast-rotating cluster members as a function of their luminosity and age. The average radii are compared with the predictions of both standard evolutionary models and variants that include magnetic inhibition of convection and starspots. Results: At a given luminosity, the stellar radii in NGC 2516 and NGC 2547 are larger than predicted by standard evolutionary models at the ages of these clusters. The discrepancy is least pronounced and not significant (≃10 per cent) in zero age main sequence stars with radiative cores, but more significant in lower-mass, fully convective pre main-sequence cluster members, reaching ≃30 ± 10 per cent. The uncertain age and distance of NGC 2264 preclude a reliable determination of any discrepancy for its members. Conclusions: The median radii we have estimated for low-mass fully convective stars in the older clusters are inconsistent (at the 2-3σ level) with non-magnetic evolutionary models and more consistent with models that incorporate the effects of magnetic fields or dark starspots. The available models suggest this requires either surface magnetic fields exceeding 2.5 kG, spots that block about 30 per cent of the photospheric flux, or a more moderate combination

  6. Investigation of multiple stellar populations in globular clusters with the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Smolinski, Jason P.

    This dissertation describes the study of abundance variations among stars in Galactic globular clusters using the large set of spectroscopic data collected by the Sloan Digital Sky Survey (SDSS). Globular clusters have typically been considered to be simple stellar populations---groups of stars that are coeval and chemically homogeneous. Observations within the last forty years have shed light on the possibility that they are not so simple after all by revealing the presence of star-to-star variations in light-element abundances. Additionally, several globular clusters are known to harbor multiple populations of stars by the presence of multiple sequences on a color-magnitude diagram. In this study, the procedure for membership selection is first described. Stars are selected from the vast data set available from SDSS Data Release 7 and several cuts are made to reduce the sample down to only those stars that are members of the globular clusters in this sample. This procedure is also performed on three open clusters as well and is further used to validate the current SEGUE Stellar Parameter Pipeline. CN and CH molecular absorption indices are then measured for all globular cluster member stars and their distributions are analyzed. Bimodal distributions in CN are seen on the red giant branch in all clusters with [Fe/H] > -2.1, and hints of bimodality are seen for two metal-poor clusters as well. CN-CH anticorrelations are also seen and the implications are discussed. The observed distributions of CN absorption bandstrengths are examined and compared to theoretical predictions from two-population models. These results are combined with radial distributions and positions on the color-magnitude diagram as evidence for the presence of multiple populations of stars within the clusters in this sample.

  7. Spectroscopic Confirmation of a Massive Red-sequence Selected Galaxy Cluster at Z=1.34 in the SpARCS-South Cluster Survey

    NASA Technical Reports Server (NTRS)

    Wilson, Gillian; Demarco, Ricardo; Muzzin, Adam; Yee, H.K.C.; Lacy, Mark; Surace, Jason; Gilbank, David; Blindert, Kris; Hoekstra, Henk; Majumdar, Subhabrata; Gardner, Jonathan P; Gladders, Michael D.; Lonsdale, Carol

    2008-01-01

    The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a z'-passband imaging survey, consisting of deep (z' approx. 24 AB) observations made from both hemispheres using the CFHT 3.6m and CTIO 4m telescopes. The survey was designed with the primary aim of detecting galaxy clusters at z > 1. In tandem with pre-existing 3.6 micron observations from the Spitzer Space Telescope SWIRE Legacy Survey, SpARCS detects clusters using an infrared adaptation of the two-filter red-sequence cluster technique. The total effective area of the SpARCS cluster survey is 41.9 sq deg. In this paper, we provide an overview of the 13.6 sq deg Southern CTIO/MOSAICII observations. The 28.3 sq deg Northern CFHT/MegaCam observations are summarized in a companion paper by Muzzin et al. (2008a). In this paper, we also report spectroscopic confirmation of SpARCS J003550-431224, a very rich galaxy cluster at z = 1.335, discovered in the ELAIS-S1 field. To date, this is the highest spectroscopically confirmed redshift for a galaxy cluster discovered using the red-sequence technique. Based on nine confirmed members, SpARCS J003550-431224 has a preliminary velocity dispersion of 1050+/-230 km/s. With its proven capability for efficient cluster detection, SpARCS is a demonstration that we have entered an era of large, homogeneously-selected z > 1 cluster surveys.

  8. Rapid Survey of Wasting and Stunting in Children: Whats New, Whats Old and Whats the Buzz?

    PubMed

    Dasgupta, Rajib; Sinha, Dipa; Yumnam, Veda

    2016-01-01

    Nationwide Rapid Survey on Children (RSoC), conducted by the Ministry of Women and Child Development and UNICEF in 2013-14 showed a marked improvement in the status of the child malnutrition over the third National Family Health Survey (NFHS-3) that was conducted in 2005-06. Despite some impressive gains in the anthropometric indicators of malnutrition, the absolute levels remain high, and of concern. Despite these gains, the feeding indicators remain stagnant. The programmatic responses need to adopt a multi-sectoral comprehensive approach with regular and comprehensive nutrition surveillance and recognize the epidemiological diversity. PMID:26840673

  9. OPEN CLUSTERS IN THE MILKY WAY OUTER DISK: NEWLY DISCOVERED AND UNSTUDIED CLUSTERS IN THE SPITZER GLIMPSE-360, CYG-X, AND SMOG SURVEYS

    SciTech Connect

    Zasowski, G.; Beaton, R. L.; Hamm, K. K.; Majewski, S. R.; Patterson, R. J.; Babler, B.; Churchwell, E.; Meade, M.; Whitney, B. A.; Benjamin, R. A.; Watson, C.

    2013-09-15

    Open stellar clusters are extremely valuable probes of Galactic structure, star formation, kinematics, and chemical abundance patterns. Near-infrared (NIR) data have enabled the detection of hundreds of clusters hidden from optical surveys, and mid-infrared (MIR) data are poised to offer an even clearer view into the most heavily obscured parts of the Milky Way. We use new MIR images from the Spitzer GLIMPSE-360, Cyg-X, and SMOG surveys to visually identify a large number of open cluster candidates in the outer disk of the Milky Way (65 Degree-Sign < l < 265 Degree-Sign ). Using NIR color-magnitude diagrams, stellar isochrones, and stellar reddening estimates, we derive cluster parameters (metallicity, distance, reddening) for those objects without previous identification and/or parameters in the literature. In total, we present coordinates and sizes of 20 previously unknown open cluster candidates; for 7 of these we also present metallicity, distance, and reddening values. In addition, we provide the first estimates of these values for nine clusters that had been previously cataloged. We compare our cluster sizes and other derived parameters to those in the open cluster catalog of Dias et al. and find strong similarities except for a higher mean reddening for our objects, which signifies our increased detection sensitivity in regions of high extinction. The results of this cluster search and analysis demonstrate the ability of MIR imaging and photometry to augment significantly the current census of open clusters in the Galaxy.

  10. The Second Most Distant Cluster of Galaxies in the Extended Medium Sensitivity Survey

    NASA Technical Reports Server (NTRS)

    Donahue, Megan; Voit, G. Mark; Scharf, Caleb A.; Gioia, Isabella M.; Mullis, Christopher R.; Hughes, John P.; Stocke, John T.

    1999-01-01

    We report on our ASCA, Keck, and ROSAT observations of MS 1137.5+6625, the second most distant cluster of galaxies in the Einstein Extended Medium Sensitivity Survey (EMSS), at redshift 0.78. We now have a full set of X-ray temperatures, optical velocity dispersions, and X-ray images for a complete, high-redshift sample of clusters of galaxies drawn from the EMSS. Our ASCA observations of MS 1137.5 +6625 yield a temperature of 5.7 (+2.1)(-1.1) keV and a metallicity of 0.43 (+40)(-3.7) solar, with 90% confidence limits. Keck II spectroscopy of 22 cluster members reveals a velocity dispersion of 884 (+185)(-124) km 24/s. This cluster is the most distant in the sample with a detected iron line. We also derive a mean abundance at z = 0.8 by simultaneously fitting X-ray data for the two z = 0.8 clusters, and obtain an abundance of Z(sub Fe) = 0.33 (+.26)(-.23). Our ROSAT observations show that MS 1137.5+6625 is regular and highly centrally concentrated. Fitting of a Beta model to the X-ray surface brightness yields a core radius of only 71/h kpc (q(sub o) = 0.1) with Beta = 0.70(+.45)(-.15) The gas mass interior to 0.5/h Mpc is thus 1.2 (+0.2)(-0.3) X 10(exp 13) h(exp - 5/2) Solar Mass (q(sub o) = 0.1). If the cluster's gas is nearly isothermal and in hydrostatic equilibrium with the cluster potential, the total mass of the cluster within this same region is 2.1(+1.5)(-0.8) X 10exp 14)/h Solar Mass, giving a gas fraction of 0.06 +/-0.04 h (exp -3/2). This cluster is the highest redshift EMSS cluster showing evidence for a possible cooling flow (about 20-400 Solar Mass/yr). The velocity dispersion, temperature, gas fraction, and iron abundance of MS 1137.5+6625 are all statistically the same as those properties in lower red- shift clusters of similar luminosity. With this cluster's temperature now in hand, we derive a high-redshift temperature function for EMSS clusters at 0.5 < z < 0.9 and compare it with temperature functions at lower redshifts, showing that the

  11. New brown dwarfs in Upper Sco using UKIDSS Galactic Cluster Survey science verification data

    NASA Astrophysics Data System (ADS)

    Lodieu, N.; Hambly, N. C.; Jameson, R. F.; Hodgkin, S. T.; Carraro, G.; Kendall, T. R.

    2007-01-01

    We present first results from a deep (J = 18.7), wide-field (6.5deg2) infrared (ZY JHK) survey in the Upper Sco association conducted within the science verification phase of the United Kingdom Infrared Telescope Infrared Deep Sky Survey Galactic Cluster Survey (GCS). Cluster members define a sequence well separated from field stars in the (Z - J, Z) colour-magnitude diagram. We have selected a total of 164 candidates with J = 10.5-18.7 mag from the (Z - J, Z) and (Y - J, Y) diagrams. We further investigated the location of those candidates in the other colour-magnitude and colour-colour diagrams to weed out contaminants. The cross-correlation of the GCS catalogue with the Two-Micron All-Sky Survey data base confirms the membership of 116 photometric candidates down to 20 Jupiter masses as they lie within a 2σ circle centred on the association mean motion. The final list of cluster members contains 129 sources with masses between 0.3 and 0.007 Msolar. We extracted a dozen new low-mass brown dwarfs below 20 MJup, the limit of previous surveys in the region. Finally, we have derived the mass function in Upper Sco over the 0.3-0.01 Msolar mass range, best fit by a single segment with a slope of index α = 0.6 +/- 0.1, in agreement with previous determination in open clusters. Based on observations made with the United Kingdom Infrared Telescope, operated by the Joint Astronomy Centre on behalf of the UK Particle Physics and Astronomy Research Council. E-mail: nl41@star.le.ac.uk

  12. The XMM Cluster Survey: evolution of the velocity dispersion - temperature relation over half a Hubble time

    NASA Astrophysics Data System (ADS)

    Wilson, Susan; Hilton, Matt; Rooney, Philip J.; Caldwell, Caroline; Kay, Scott T.; Collins, Chris A.; McCarthy, Ian G.; Romer, A. Kathy; Bermeo, Alberto; Bernstein, Rebecca; da Costa, Luiz; Gifford, Daniel; Hollowood, Devon; Hoyle, Ben; Jeltema, Tesla; Liddle, Andrew R.; Maia, Marcio A. G.; Mann, Robert G.; Mayers, Julian A.; Mehrtens, Nicola; Miller, Christopher J.; Nichol, Robert C.; Ogando, Ricardo; Sahlén, Martin; Stahl, Benjamin; Stott, John P.; Thomas, Peter A.; Viana, Pedro T. P.; Wilcox, Harry

    2016-08-01

    We measure the evolution of the velocity dispersion-temperature (σv-TX) relation up to z = 1 using a sample of 38 galaxy clusters drawn from the XMM Cluster Survey. This work improves upon previous studies by the use of a homogeneous cluster sample and in terms of the number of high redshift clusters included. We present here new redshift and velocity dispersion measurements for 12 z > 0.5 clusters observed with the GMOS instruments on the Gemini telescopes. Using an orthogonal regression method, we find that the slope of the relation is steeper than that expected if clusters were self-similar, and that the evolution of the normalisation is slightly negative, but not significantly different from zero (σv∝T0.86 ± 0.14E(z)-0.37 ± 0.33). We verify our results by applying our methods to cosmological hydrodynamical simulations. The lack of evolution seen in our data is consistent with simulations that include both feedback and radiative cooling.

  13. The HST/ACS Coma Cluster Survey. VIII. Barred Disk Galaxies in the Core of the Coma Cluster

    NASA Astrophysics Data System (ADS)

    Marinova, Irina; Jogee, Shardha; Weinzirl, Tim; Erwin, Peter; Trentham, Neil; Ferguson, Henry C.; Hammer, Derek; den Brok, Mark; Graham, Alister W.; Carter, David; Balcells, Marc; Goudfrooij, Paul; Guzmán, Rafael; Hoyos, Carlos; Mobasher, Bahram; Mouhcine, Mustapha; Peletier, Reynier F.; Peng, Eric W.; Verdoes Kleijn, Gijs

    2012-02-01

    We use high-resolution (~0farcs1) F814W Advanced Camera for Surveys (ACS) images from the Hubble Space Telescope ACS Treasury survey of the Coma cluster at z ~ 0.02 to study bars in massive disk galaxies (S0s), as well as low-mass dwarf galaxies in the core of the Coma cluster, the densest environment in the nearby universe. Our study helps to constrain the evolution of bars and disks in dense environments and provides a comparison point for studies in lower density environments and at higher redshifts. Our results are: (1) we characterize the fraction and properties of bars in a sample of 32 bright (M V <~ -18, M * > 109.5 M ⊙) S0 galaxies, which dominate the population of massive disk galaxies in the Coma core. We find that the measurement of a bar fraction among S0 galaxies must be handled with special care due to the difficulty in separating unbarred S0s from ellipticals, and the potential dilution of the bar signature by light from a relatively large, bright bulge. The results depend sensitively on the method used: the bar fraction for bright S0s in the Coma core is 50% ± 11%, 65% ± 11%, and 60% ± 11% based on three methods of bar detection, namely, strict ellipse fit criteria, relaxed ellipse fit criteria, and visual classification. (2) We compare the S0 bar fraction across different environments (the Coma core, A901/902, and Virgo) adopting the critical step of using matched samples and matched methods in order to ensure robust comparisons. We find that the bar fraction among bright S0 galaxies does not show a statistically significant variation (within the error bars of ±11%) across environments which span two orders of magnitude in galaxy number density (n ~ 300-10,000 galaxies Mpc-3) and include rich and poor clusters, such as the core of Coma, the A901/902 cluster, and Virgo. We speculate that the bar fraction among S0s is not significantly enhanced in rich clusters compared to low-density environments for two reasons. First, S0s in rich clusters

  14. THE HST/ACS COMA CLUSTER SURVEY. VIII. BARRED DISK GALAXIES IN THE CORE OF THE COMA CLUSTER

    SciTech Connect

    Marinova, Irina; Jogee, Shardha; Weinzirl, Tim; Erwin, Peter; Trentham, Neil; Ferguson, Henry C.; Goudfrooij, Paul; Hammer, Derek; Den Brok, Mark; Peletier, Reynier F.; Kleijn, Gijs V.; Graham, Alister W.; Carter, David; Mouhcine, Mustapha; Balcells, Marc; Guzman, Rafael; Hoyos, Carlos; Mobasher, Bahram; Peng, Eric W. E-mail: sj@astro.as.utexas.edu

    2012-02-20

    We use high-resolution ({approx}0.''1) F814W Advanced Camera for Surveys (ACS) images from the Hubble Space Telescope ACS Treasury survey of the Coma cluster at z {approx} 0.02 to study bars in massive disk galaxies (S0s), as well as low-mass dwarf galaxies in the core of the Coma cluster, the densest environment in the nearby universe. Our study helps to constrain the evolution of bars and disks in dense environments and provides a comparison point for studies in lower density environments and at higher redshifts. Our results are: (1) we characterize the fraction and properties of bars in a sample of 32 bright (M{sub V} {approx}< -18, M{sub *} > 10{sup 9.5} M{sub Sun }) S0 galaxies, which dominate the population of massive disk galaxies in the Coma core. We find that the measurement of a bar fraction among S0 galaxies must be handled with special care due to the difficulty in separating unbarred S0s from ellipticals, and the potential dilution of the bar signature by light from a relatively large, bright bulge. The results depend sensitively on the method used: the bar fraction for bright S0s in the Coma core is 50% {+-} 11%, 65% {+-} 11%, and 60% {+-} 11% based on three methods of bar detection, namely, strict ellipse fit criteria, relaxed ellipse fit criteria, and visual classification. (2) We compare the S0 bar fraction across different environments (the Coma core, A901/902, and Virgo) adopting the critical step of using matched samples and matched methods in order to ensure robust comparisons. We find that the bar fraction among bright S0 galaxies does not show a statistically significant variation (within the error bars of {+-}11%) across environments which span two orders of magnitude in galaxy number density (n {approx} 300-10,000 galaxies Mpc{sup -3}) and include rich and poor clusters, such as the core of Coma, the A901/902 cluster, and Virgo. We speculate that the bar fraction among S0s is not significantly enhanced in rich clusters compared to low

  15. Simulation of a Combined SZE and Weak Lensing Cluster Survey for Amiba Experiment

    NASA Astrophysics Data System (ADS)

    Umetsu, Keiichi; Chiueh, Tzihong; Lin, Kai-Yang; Wu, Jun-Mein; Tseng, Yao-Huan

    We present simulations of interferometric Sunyaev-Zel'dovich effect (SZE) and optical weak lenisng observations for the forthcoming AMiBA experiment, aiming at searching for high-redshift clusters of galaxies. On the basis of simulated sky maps, we have derived theoretical halo number counts and redshift distributions of selected halo samples for an AMiBA SZE survey and a weak lensing follow-up survey. By utilizing the conditional number counts of weak lensing halos with the faint SZE detection, we show that a combined SZE and weak lensing survey can gain an additional fainter halo sample at a given false positive rate, which cannot be obtained from either survey alone.

  16. AN INTENSIVE HUBBLE SPACE TELESCOPE SURVEY FOR z>1 TYPE Ia SUPERNOVAE BY TARGETING GALAXY CLUSTERS

    SciTech Connect

    Dawson, K. S.; Aldering, G.; Barbary, K.; Faccioli, L.; Fakhouri, H. K.; Goldhaber, G.; Amanullah, R.; Barrientos, L. F.; Brodwin, M.; Connolly, N.; Dey, A.; Doi, M.; Donahue, M.; Eisenhardt, P.; Ellingson, E.; Fadeyev, V.; Fruchter, A. S.; Gilbank, D. G.; Gladders, M. D.; Gonzalez, A. H.

    2009-11-15

    We present a new survey strategy to discover and study high-redshift Type Ia supernovae (SNe Ia) using the Hubble Space Telescope (HST). By targeting massive galaxy clusters at 0.9 < z < 1.5, we obtain a twofold improvement in the efficiency of finding SNe compared to an HST field survey and a factor of 3 improvement in the total yield of SN detections in relatively dust-free red-sequence galaxies. In total, sixteen SNe were discovered at z>0.95, nine of which were in galaxy clusters. This strategy provides an SN sample that can be used to decouple the effects of host-galaxy extinction and intrinsic color in high-redshift SNe, thereby reducing one of the largest systematic uncertainties in SN cosmology.

  17. X-ray selected galaxy clusters in the Pan-STARRS Medium Deep Survey

    NASA Astrophysics Data System (ADS)

    Ebeling, H.; Edge, A. C.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Huber, M. E.; Kaiser, N.; Price, P. A.; Tonry, J. L.

    2013-06-01

    We present the results of a pilot study for the extended Massive Cluster Survey (eMACS), a comprehensive search for distant, X-ray luminous galaxy clusters at z > 0.5. Our pilot study applies the eMACS concept to the 71 deg2 area extended by the 10 fields of the Pan-STARRS1 (PS1) Medium Deep Survey (MDS). Candidate clusters are identified by visual inspection of PS1 images in the g, r, i and z bands in a 5 × 5 arcmin2 region around X-ray sources detected in the ROSAT All-Sky Survey (RASS). To test and optimize the eMACS X-ray selection criteria, our pilot study uses the largest possible RASS data base, i.e. all RASS sources listed in the Bright and Faint Source Catalogues (BSC and FSC) that fall within the MDS footprint. We apply no additional constraints regarding X-ray flux, spectral hardness ratio or photon statistics and lower the redshift threshold to z > 0.3 to extend the probed luminosity range to poorer systems. Scrutiny of PS1/MDS images for 41 BSC and 200 FSC sources combined with dedicated spectroscopic follow-up observations results in a sample of 11 clusters with estimated or spectroscopic redshifts of z > 0.3. In order to assess and quantify the degree of point source contamination of the observed RASS fluxes, we examine archival Chandra data obtained in targeted and serendipitous observations of six of the 11 clusters found. As expected, the diffuse emission from all six systems is contaminated by point sources to some degree, and for half of them active galactic nucleus emission dominates. X-ray follow-up observations will thus be crucial in order to establish robust cluster luminosities for eMACS clusters. Although the small number of distant X-ray luminous clusters in the MDS does not allow us to make firm predictions for the over 20 000 deg2 of extragalactic sky covered by eMACS, the identification of two extremely promising eMACS cluster candidates at z ≳ 0.6 (both yet to be observed with Chandra) in such a small solid angle is encouraging

  18. Strong Lens Models for 10 Galaxy Clusters from the Sloan Giant Arcs Survey

    NASA Astrophysics Data System (ADS)

    Dunham, Samuel; Sharon, Keren; Bayliss, Matthew; Dahle, Hakon; Florian, Michael; Gladders, Michael; Johnson, Traci; Murray, Katherine; Rigby, Jane R.; Whitaker, Katherine E.; Wuyts, Eva

    2016-01-01

    We present the results from modeling several strong gravitational lenses as part of the Sloan Giant Arcs Survey (SGAS). HST cannot resolve star-formation in galaxies at redshifts >~1 because they are too far away, but by using the magnification by galaxy clusters at these redshifts (1cluster we can then make an accurate calculation of the mass as well as constrain the dark matter halo that envelops the cluster. With the computed lensing magnification, we can calculate the luminosity, size, star formation rate, and stellar mass of the background galaxies.

  19. Clustering of far-infrared galaxies in the AKARI All-Sky Survey North

    NASA Astrophysics Data System (ADS)

    Pollo, A.; Takeuchi, T. T.; Solarz, A.; Rybka, P.; Suzuki, T. L.; Pȩpiak, A.; Oyabu, S.

    2013-10-01

    We present the measurements of the angular two-point correlation function for AKARI 90-μm point sources, detected outside the Milky Way plane and other regions characterized by high Galactic extinction in the northern Galactic hemisphere, and categorized as extragalactic sources according to our far-infrared-color based criterion. Together with our previous work (Pollo et al., 2013) this is the first measurement of the large-scale angular clustering of galaxies selected in the far-infrared after IRAS. We present the first attempt to estimate the spatial clustering properties of AKARI All-Sky galaxies and we conclude that they are mostly a very nearby ( z ≤ 0.1) population of moderately clustered galaxies. We measure their correlation length r 0 ~ 4.5 h -1 Mpc, which is consistent with the assumption that the FIS AKARI All-Sky surveys observes mostly a nearby star-forming population of galaxies.

  20. A survey of rich clusters of galaxies with HEAO 1. II

    NASA Technical Reports Server (NTRS)

    Ulmer, M. P.; Kowalski, M. P.; Cruddace, R. G.; Meekins, J.; Smathers, H.; Yentis, D.; Wood, K.; Mcnutt, D.; Chubb, T.; Johnson, M.

    1981-01-01

    Results are presented of an X-ray survey of approximately 1900 Abell clusters of galaxies performed with the NRL large-area X-ray detectors on HEAO 1. The cluster luminosity function derived from the observations made at ecliptic longitudes between 80 and 180 deg and 260 and 360 deg is fit with both power law and exponential relations, and used to estimate a total contribution of Abell clusters to the volume emissivity of the diffuse X-ray background of between 3 and 10%. No strong correlation is found between X-ray luminosity and Bautz-Morgan class, richness class or 26-MHz radio power, although B-M type I and Abell richness class 3 appear more likely to be strong X-ray sources. A correlation is suggested between optical radius and X-ray luminosity.

  1. Massive open star clusters using the VVV survey. III. A young massive cluster at the far edge of the Galactic bar

    NASA Astrophysics Data System (ADS)

    Ramírez Alegría, S.; Borissova, J.; Chené, A. N.; O'Leary, E.; Amigo, P.; Minniti, D.; Saito, R. K.; Geisler, D.; Kurtev, R.; Hempel, M.; Gromadzki, M.; Clarke, J. R. A.; Negueruela, I.; Marco, A.; Fierro, C.; Bonatto, C.; Catelan, M.

    2014-04-01

    Context. Young massive clusters are key to map the Milky Way's structure, and near-infrared large area sky surveys have contributed strongly to the discovery of new obscured massive stellar clusters. Aims: We present the third article in a series of papers focused on young and massive clusters discovered in the VVV survey. This article is dedicated to the physical characterization of VVV CL086, using part of its OB-stellar population. Methods: We physically characterized the cluster using JHKS near-infrared photometry from ESO public survey VVV images, using the VVV-SkZ pipeline, and near-infrared K-band spectroscopy, following the methodology presented in the first article of the series. Results: Individual distances for two observed stars indicate that the cluster is located at the far edge of the Galactic bar. These stars, which are probable cluster members from the statistically field-star decontaminated CMD, have spectral types between O9 and B0 V. According to our analysis, this young cluster (1.0 Myr < age < 5.0 Myr) is located at a distance of 11+5-6 kpc, and we estimate a lower limit for the cluster total mass of (2.8+1.6-1.4) · 103 M⊙. It is likely that the cluster contains even earlier and more massive stars. Based on observations taken within the ESO VISTA Public Survey VVV (programme ID 179.B-2002), and with ISAAC, VLT, ESO (programme 087.D-0341A).Near-IR photometry of the most probable cluster members is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/564/L9

  2. A rapid method of grading cataract in epidemiological studies and eye surveys.

    PubMed Central

    Mehra, V; Minassian, D C

    1988-01-01

    A rapid method of grading clinically important central lens opacities has been developed for use in eye surveys and in epidemiological studies of cataract and has been field-tested in a specifically designed observer agreement study in a survey of a rural community in Central India. The grading method is based on simple measurement of the area of lens opacity that obscures the red reflex relative to the area of clear red reflex, as visualised through the undilated normal pupil. Good to almost perfect agreements were attained between two ophthalmologists and two trained ophthalmic assistants for overall grades of central lens opacity. Most disagreements were trivial in nature and were concerned with difficulties in distinguishing grade 0 from grade 1, and with hazy appearance of the red reflex in high myopes and in cases of early nuclear sclerosis. Teaching materials including video tape and slides for training survey teams and other workers are in preparation. PMID:3207653

  3. Determining the Role of Merging in the Growth of the Galaxy Cluster Population in the Massive and Distant Clusters of WISE Survey

    NASA Astrophysics Data System (ADS)

    Brodwin, Mark; Decker, Bandon; Gonzalez, Anthony; Stanford, Adam; Eisenhardt, Peter; Stern, Daniel; Wylezalek, Dominika; Marrone, Daniel; Stalder, Brian; Mantz, Adam; Galametz, Audrey

    2015-10-01

    We propose to obtain deep Spitzer/IRAC imaging of 14 distant (z ~ 1), stellar mass-selected galaxy clusters from the Massive and Distant Clusters of WISE Survey (MaDCoWS) for which robust Sunyaev-Zel'dovich (SZ)-based masses spanning ~2-10 x 10^14 Msun have been measured. These proposed IRAC data, along with joint HST imaging, will allow us to directly test key predictions of current models of cluster formation. These models posit that galaxy-galaxy merging drives the bursts of star formation and AGN activity seen in high redshift Spitzer studies of low-mass clusters, and predict the rate of such activity should be a function of total cluster mass. As clusters grow in mass (and hence velocity dispersion), the merging efficiency drops and the growth of the galaxy population, via both mergers and star formation, should cease. By measuring the cluster stellar mass function, as a function of both mass and morphological type, we will directly confirm or refute this model. We will also identify, on the basis of IRAC colors and HST morphologies, the AGN content in these clusters. We will thus test the prediction that the incidence of AGN should be higher in the lower mass clusters. Finally, we will measure the stellar mass fraction as a function of total mass, a crucial quantity in calibrating numerical cluster simulations that are key for cluster abundance cosmology.

  4. Crowded Cluster Cores. Algorithms for Deblending in Dark Energy Survey Images

    DOE PAGESBeta

    Zhang, Yuanyuan; McKay, Timothy A.; Bertin, Emmanuel; Jeltema, Tesla; Miller, Christopher J.; Rykoff, Eli; Song, Jeeseon

    2015-10-26

    Deep optical images are often crowded with overlapping objects. We found that this is especially true in the cores of galaxy clusters, where images of dozens of galaxies may lie atop one another. Accurate measurements of cluster properties require deblending algorithms designed to automatically extract a list of individual objects and decide what fraction of the light in each pixel comes from each object. In this article, we introduce a new software tool called the Gradient And Interpolation based (GAIN) deblender. GAIN is used as a secondary deblender to improve the separation of overlapping objects in galaxy cluster cores inmore » Dark Energy Survey images. It uses image intensity gradients and an interpolation technique originally developed to correct flawed digital images. Our paper is dedicated to describing the algorithm of the GAIN deblender and its applications, but we additionally include modest tests of the software based on real Dark Energy Survey co-add images. GAIN helps to extract an unbiased photometry measurement for blended sources and improve detection completeness, while introducing few spurious detections. When applied to processed Dark Energy Survey data, GAIN serves as a useful quick fix when a high level of deblending is desired.« less

  5. Crowded Cluster Cores: An Algorithm for Deblending in Dark Energy Survey Images

    NASA Astrophysics Data System (ADS)

    Zhang, Yuanyuan; McKay, Timothy A.; Bertin, Emmanuel; Jeltema, Tesla; Miller, Christopher J.; Rykoff, Eli; Song, Jeeseon

    2015-11-01

    Deep optical images are often crowded with overlapping objects. This is especially true in the cores of galaxy clusters, where images of dozens of galaxies may lie atop one another. Accurate measurements of cluster properties require deblending algorithms designed to automatically extract a list of individual objects and decide what fraction of the light in each pixel comes from each object. In this article, we introduce a new software tool called the Gradient And Interpolation based (GAIN) deblender. GAIN is used as a secondary deblender to improve the separation of overlapping objects in galaxy cluster cores in Dark Energy Survey images. It uses image intensity gradients and an interpolation technique originally developed to correct flawed digital images. This paper is dedicated to describing the algorithm of the GAIN deblender and its applications, but we additionally include modest tests of the software based on real Dark Energy Survey co-add images. GAIN helps to extract an unbiased photometry measurement for blended sources and improve detection completeness, while introducing few spurious detections. When applied to processed Dark Energy Survey data, GAIN serves as a useful quick fix when a high level of deblending is desired.

  6. Crowded Cluster Cores. Algorithms for Deblending in Dark Energy Survey Images

    SciTech Connect

    Zhang, Yuanyuan; McKay, Timothy A.; Bertin, Emmanuel; Jeltema, Tesla; Miller, Christopher J.; Rykoff, Eli; Song, Jeeseon

    2015-10-26

    Deep optical images are often crowded with overlapping objects. We found that this is especially true in the cores of galaxy clusters, where images of dozens of galaxies may lie atop one another. Accurate measurements of cluster properties require deblending algorithms designed to automatically extract a list of individual objects and decide what fraction of the light in each pixel comes from each object. In this article, we introduce a new software tool called the Gradient And Interpolation based (GAIN) deblender. GAIN is used as a secondary deblender to improve the separation of overlapping objects in galaxy cluster cores in Dark Energy Survey images. It uses image intensity gradients and an interpolation technique originally developed to correct flawed digital images. Our paper is dedicated to describing the algorithm of the GAIN deblender and its applications, but we additionally include modest tests of the software based on real Dark Energy Survey co-add images. GAIN helps to extract an unbiased photometry measurement for blended sources and improve detection completeness, while introducing few spurious detections. When applied to processed Dark Energy Survey data, GAIN serves as a useful quick fix when a high level of deblending is desired.

  7. THE ACS VIRGO CLUSTER SURVEY. XVII. THE SPATIAL ALIGNMENT OF GLOBULAR CLUSTER SYSTEMS WITH EARLY-TYPE HOST GALAXIES

    SciTech Connect

    Wang Qiushi; Peng, Eric W.; Blakeslee, John P.; Cote, Patrick; Ferrarese, Laura; Jordan, Andres; Mei, Simona; West, Michael J.

    2013-06-01

    We study the azimuthal distribution of globular clusters (GCs) in early-type galaxies and compare them to their host galaxies using data from the ACS Virgo Cluster Survey. We find that in host galaxies with visible elongation ({epsilon} > 0.2) and intermediate to high luminosities (M{sub z} < -19), the GCs are preferentially aligned along the major axis of the stellar light. The red (metal-rich) GC subpopulations show strong alignment with the major axis of the host galaxy, which supports the notion that these GCs are associated with metal-rich field stars. The metal-rich GCs in lenticular galaxies show signs of being more strongly associated with disks rather than bulges. Surprisingly, we also find that the blue (metal-poor) GCs can also show the same correlation. If the metal-poor GCs are part of the early formation of the halo and built up through mergers, then our results support a picture where halo formation and merging occur anisotropically, and that the present-day major axis is an indicator of the preferred merging axis.

  8. WEAK LENSING MEASUREMENT OF GALAXY CLUSTERS IN THE CFHTLS-WIDE SURVEY

    SciTech Connect

    Shan Huanyuan; Tao Charling; Kneib, Jean-Paul; Jauzac, Mathilde; Limousin, Marceau; Fan Zuhui; Massey, Richard; Rhodes, Jason; Thanjavur, Karun; McCracken, Henry J.

    2012-03-20

    We present the first weak gravitational lensing analysis of the completed Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). We study the 64 deg{sup 2} W1 field, the largest of the CFHTLS-Wide survey fields, and present the largest contiguous weak lensing convergence 'mass map' yet made. 2.66 million galaxy shapes are measured, using the Kaiser Squires and Broadhurst Method (KSB) pipeline verified against high-resolution Hubble Space Telescope imaging that covers part of the CFHTLS. Our i'-band measurements are also consistent with an analysis of independent r'-band imaging. The reconstructed lensing convergence map contains 301 peaks with signal-to-noise ratio {nu} > 3.5, consistent with predictions of a {Lambda}CDM model. Of these peaks, 126 lie within 3.'0 of a brightest central galaxy identified from multicolor optical imaging in an independent, red sequence survey. We also identify seven counterparts for massive clusters previously seen in X-ray emission within 6 deg{sup 2} XMM-LSS survey. With photometric redshift estimates for the source galaxies, we use a tomographic lensing method to fit the redshift and mass of each convergence peak. Matching these to the optical observations, we confirm 85 groups/clusters with {chi}{sup 2}{sub reduced} < 3.0, at a mean redshift (z{sub c} ) = 0.36 and velocity dispersion ({sigma}{sub c}) = 658.8 km s{sup -1}. Future surveys, such as DES, LSST, KDUST, and EUCLID, will be able to apply these techniques to map clusters in much larger volumes and thus tightly constrain cosmological models.

  9. The HST/ACS Coma Cluster Survey - X. Nuclear star clusters in low-mass early-type galaxies: scaling relations

    NASA Astrophysics Data System (ADS)

    den Brok, Mark; Peletier, Reynier F.; Seth, Anil; Balcells, Marc; Dominguez, Lilian; Graham, Alister W.; Carter, David; Erwin, Peter; Ferguson, Henry C.; Goudfrooij, Paul; Guzmán, Rafael; Hoyos, Carlos; Jogee, Shardha; Lucey, John; Phillipps, Steven; Puzia, Thomas; Valentijn, Edwin; Kleijn, Gijs Verdoes; Weinzirl, Tim

    2014-12-01

    We present scaling relations between structural properties of nuclear star clusters and their host galaxies for a sample of early-type dwarf galaxies observed as part of the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Coma Cluster Survey. We have analysed the light profiles of 200 early-type dwarf galaxies in the magnitude range 16.0 < mF814W < 22.6 mag, corresponding to -19.0 < MF814W < -12.4 mag. Nuclear star clusters are detected in 80 per cent of the galaxies, thus doubling the sample of HST-observed early-type dwarf galaxies with nuclear star clusters. We confirm that the nuclear star cluster detection fraction decreases strongly towards faint magnitudes. The luminosities of nuclear star clusters do not scale linearly with host galaxy luminosity. A linear fit yields L_nuc ˜ L_gal^{0.57± 0.05}. The nuclear star cluster-host galaxy luminosity scaling relation for low-mass early-type dwarf galaxies is consistent with formation by globular cluster (GC) accretion. We find that at similar luminosities, galaxies with higher Sérsic indices have slightly more luminous nuclear star clusters. Rounder galaxies have on average more luminous clusters. Some of the nuclear star clusters are resolved, despite the distance of Coma. We argue that the relation between nuclear star cluster mass and size is consistent with both formation by GC accretion and in situ formation. Our data are consistent with GC inspiralling being the dominant mechanism at low masses, although the observed trend with Sérsic index suggests that in situ star formation is an important second-order effect.

  10. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    SciTech Connect

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. F.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-03-31

    We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. Additionally, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  11. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    SciTech Connect

    Melchior, P.; et al.

    2015-05-21

    We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modeling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modeling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. In addition, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1 degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  12. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    DOE PAGESBeta

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; et al

    2015-03-31

    We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Sciencemore » Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. Additionally, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.« less

  13. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    NASA Astrophysics Data System (ADS)

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. Fausti; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-05-01

    We measure the weak lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey (DES). This pathfinder study is meant to (1) validate the Dark Energy Camera (DECam) imager for the task of measuring weak lensing shapes, and (2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, point spread function (PSF) modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting Navarro-Frenk-White profiles to the clusters in this study, we determine weak lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak lensing mass, and richness. In addition, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1°(approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  14. A multi-wavelength survey of AGN in massive clusters: AGN distribution and host galaxy properties

    NASA Astrophysics Data System (ADS)

    Klesman, Alison J.; Sarajedini, Vicki L.

    2014-07-01

    We investigate the effect of environment on the presence and fuelling of active galactic nuclei (AGN) by identifying galaxies hosting AGN in massive galaxy clusters and the fields around them. We have identified AGN candidates via optical variability (178), X-ray emission (74), and mid-IR SEDs (64) in multi-wavelength surveys covering regions centred on 12 galaxy clusters at redshifts 0.5 < z < 0.9. In this paper, we present the radial distribution of AGN in clusters to examine how local environment affects the presence of an AGN and its host galaxy. While distributions vary from cluster to cluster, we find that the radial distribution of AGN generally differs from that of normal galaxies. X-ray-selected AGN candidates appear to be more centrally concentrated than normal galaxies in the inner 20 per cent of the virial radius, while becoming less centrally concentrated in the outer regions. Mid-IR-selected AGN are less centrally concentrated overall. Optical variables have a similar distribution to normal galaxies in the inner regions, then become somewhat less centrally concentrated farther from the cluster centre. The host galaxies of AGN reveal a different colour distribution than normal galaxies, with many AGN hosts displaying galaxy colours in the `green valley' between the red sequence and blue star-forming normal galaxies. This result is similar to those found in field galaxy studies. The colour distribution of AGN hosts is more pronounced in disturbed clusters where minor mergers, galaxy harassment, and interactions with cluster substructure may continue to prompt star formation in the hosts. Among normal galaxies, we find that galaxy colours become generally bluer with increasing cluster radius, as is expected. However, we find no relationship between host galaxy colour and cluster radius among AGN hosts, which may indicate that processes related to the accreting supermassive black hole have a greater impact on the star-forming properties of the host galaxy

  15. Assessment of Universal Healthcare Coverage in a District of North India: A Rapid Cross-Sectional Survey Using Tablet Computers

    PubMed Central

    Singh, Tarundeep; Roy, Pritam; Jamir, Limalemla; Gupta, Saurav; Kaur, Navpreet; Jain, D. K.; Kumar, Rajesh

    2016-01-01

    Objective A rapid survey was carried out in Shaheed Bhagat Singh Nagar District of Punjab state in India to ascertain health seeking behavior and out-of-pocket health expenditures. Methods Using multistage cluster sampling design, 1,008 households (28 clusters x 36 households in each cluster) were selected proportionately from urban and rural areas. Households were selected through a house-to-house survey during April and May 2014 whose members had (a) experienced illness in the past 30 days, (b) had illness lasting longer than 30 days, (c) were hospitalized in the past 365 days, or (d) had women who were currently pregnant or experienced childbirth in the past two years. In these selected households, trained investigators, using a tablet computer-based structured questionnaire, enquired about the socio-demographics, nature of illness, source of healthcare, and healthcare and household expenditure. The data was transmitted daily to a central server using wireless communication network. Mean healthcare expenditures were computed for various health conditions. Catastrophic healthcare expenditure was defined as more than 10% of the total annual household expenditure on healthcare. Chi square test for trend was used to compare catastrophic expenditures on hospitalization between households classified into expenditure quartiles. Results The mean monthly household expenditure was 15,029 Indian Rupees (USD 188.2). Nearly 14.2% of the household expenditure was on healthcare. Fever, respiratory tract diseases, gastrointestinal diseases were the common acute illnesses, while heart disease, diabetes mellitus, and respiratory diseases were the more common chronic diseases. Hospitalizations were mainly due to cardiovascular diseases, gastrointestinal problems, and accidents. Only 17%, 18%, 20% and 31% of the healthcare for acute illnesses, chronic illnesses, hospitalizations and childbirth was sought in the government health facilities. Average expenditure in government health

  16. VizieR Online Data Catalog: Hectospec survey of SZ clusters (HeCS-SZ) (Rines+, 2016)

    NASA Astrophysics Data System (ADS)

    Rines, K. J.; Geller, M. J.; Diaferio, A.; Hwang, H. S.

    2016-05-01

    HeCS-SZ is an extension of the HeCS survey to include clusters that enable the construction of an SZ-limited sample. We measured 7721 new redshifts with MMT/Hectospec in 21 clusters selected from the Planck SZ catalog (2014A&A...571A..20P; arXiv:1502.01597). We combine these new measurements with the existing HeCS (Hectospec Cluster Survey; Rines et al. 2013, J/ApJ/767/15) and CIRS (Cluster Infall Regions in SDSS project; Rines & Diaferio 2006, J/AJ/132/1275) surveys and with data from the literature to construct a total sample of 123 clusters. We use SDSS photometry for all clusters. The HeCS is a spectroscopic survey of 58 galaxy clusters at moderate redshift (z=0.1-0.3) with MMT/Hectospec. HeCS includes all clusters with ROSAT X-ray fluxes of f_X>5x10-12erg/s at [0.5-2.0]keV from the Bright Cluster Survey (BCS; Ebeling et al. 1998, J/MNRAS/301/881) or REFLEX survey (Bohringer et al. 2004, J/A+A/425/367) with optical imaging in the sixth Data Release (DR6) of SDSS (Adelman-McCarthy et al. 2008, II/282; superseded by II/294). CIRS used spectroscopy from the fourth Data Release of SDSS. Table 3 lists 168 redshifts measured with the FAST instrument on the 1.5m Tillinghast telescope at the Fred Lawrence Whipple Observatory. The additional single-slit spectra from FAST reduce the incompleteness of bright (SDSS r<~16.5) galaxies in the HeCS-SZ clusters. (4 data files).

  17. The ACS Virgo Cluster Survey. XII. The Luminosity Function of Globular Clusters in Early-Type Galaxies

    NASA Astrophysics Data System (ADS)

    Jordán, Andrés; McLaughlin, Dean E.; Côté, Patrick; Ferrarese, Laura; Peng, Eric W.; Mei, Simona; Villegas, Daniela; Merritt, David; Tonry, John L.; West, Michael J.

    2007-07-01

    We analyze the luminosity function of the globular clusters (GCs) belonging to the early-type galaxies observed in the ACS Virgo Cluster Survey. We have obtained maximum likelihood estimates for a Gaussian representation of the globular cluster luminosity function (GCLF) for 89 galaxies. We have also fit the luminosity functions with an ``evolved Schechter function'', which is meant to reflect the preferential depletion of low-mass GCs, primarily by evaporation due to two-body relaxation, from an initial Schechter mass function similar to that of young massive clusters in local starbursts and mergers. We find a highly significant trend of the GCLF dispersion σ with galaxy luminosity, in the sense that the GC systems in smaller galaxies have narrower luminosity functions. The GCLF dispersions of our Galaxy and M31 are quantitatively in keeping with this trend, and thus the correlation between σ and galaxy luminosity would seem more fundamental than older notions that the GCLF dispersion depends on Hubble type. We show that this narrowing of the GCLF in a Gaussian description is driven by a steepening of the cluster mass function above the classic turnover mass, as one moves to lower luminosity host galaxies. In a Schechter function description, this is reflected by a steady decrease in the value of the exponential cutoff mass scale. We argue that this behavior at the high-mass end of the GC mass function is most likely a consequence of systematic variations of the initial cluster mass function rather than long-term dynamical evolution. The GCLF turnover mass MTO is roughly constant, at MTO~=(2.2+/-0.4)×105 Msolar in bright galaxies, but it decreases slightly (by ~35% on average, with significant scatter) in dwarf galaxies with MB,gal>~-18. It could be important to allow for this effect when using the GCLF as a distance indicator. We show that part, although perhaps not all, of the variation could arise from the shorter dynamical friction timescales in less

  18. A Complete X-ray Selected Sample of Galaxy Clusters from the ROSAT North Ecliptic Pole Survey

    NASA Astrophysics Data System (ADS)

    Mullis, C. R.; Henry, J. P.; Gioia, I. M.

    1997-12-01

    We are using the ROSAT All-Sky Survey observations around the North Ecliptic Pole to construct a complete and unbiased sample of galaxy clusters in order to understand the nature of cluster evolution and determine implications for large scale structure models. Our database is unique in that it is both deep and contiguous. Here we give an update on the survey's progress and discuss a few particularly exciting results. Via optical follow-up, we have secured identifications for nearly 80% of the 465 X-ray sources in the survey area. The cluster sample now consists of 50 objects with redshifts approaching unity. Evidence for large scale structure exists at both low and high redshifts in the NEP survey. A low-z spike in the redshift distribution for NEP clusters is consistent with a previously known supercluster at 0.088. At the other extreme, we recently discovered a very distant cluster at z=0.813 which resembles a filament of galaxies. Such a massive, un-virialized cluster at high-z may be the vision quest of cosmic-web proponents. For this potential protocluster, we present a velocity dispersion analysis of its member galaxies from Keck II observations and a temperature measurement from ASCA data. We construct the cluster X-ray luminosity function at high redshifts, incorporating a rigorous treatment of our survey selection function, and compare it to previous work.

  19. High Cadence Photometric Survey of Four Southern Hemisphere Milky Way Globular Clusters

    NASA Astrophysics Data System (ADS)

    Walker, Douglas Kyle; Albrow, Michael

    2015-08-01

    The Milky Way galaxy is surrounded by some 200 compact Globular Cluster (GCs) of stars, containing up to a million stars each. At 13 billion years of age, these globular clusters are almost as old as the universe itself and were born when the first generations of stars and galaxies formed. GCs are dynamical test beds for investigating and proving theories of stellar evolution. A key parameter to understanding the evolution of GCs is the binary fraction of stars contained within a GC. Binary stars are thought to be a controlling factor in globular cluster evolution and provide a unique tool to determine crucial information about a variety of stellar characteristics such as mass, radius and luminosity. In addition to containing binary stars, GCs also harbor a wide variety of variable stars such as RR Lyrae stars and other stellar exotica, such as blue stragglers, cataclysmic variables, and low-mass X-ray binaries. Recently, a potential new class of rapidly pulsating star, hydrogen-rich subdwarf (sdO) pulsators, has been discovered in the Omega Centauri GC. At present, these Hydrogen sdO pulsators have not been detected in any other GC or among the general field star population.This talk will discuss the use of Difference Imaging Algorithms (DIAs) applied to time-series photometry data from the 10m Southern African Large Telescope (SALT) to investigate short period low amplitude variable stars in the GCs: NGC 1904, NGC 2808, NGC 4833 and NGC 5139. We will present results of• Searching for new discoveries in pulsating stars, cataclysmic variables (a white dwarf star accreting material from its companion), BY Draconis stars (rapidly rotating dwarf stars spun up by a binary companion) and contact binary stars (rapidly rotating binaries that are beginning to coalesce)• Comparison analysis of variables across clusters in relation to cluster Main Sequence regions• Determining the fraction of binary stars in the identified GCsSpecific scientific questions that are

  20. Constraining neutrino properties with a Euclid-like galaxy cluster survey

    SciTech Connect

    Cerbolini, M. Costanzi Alunno; Sartoris, B.; Borgani, S.; Xia, Jun-Qing; Biviano, A.; Viel, M. E-mail: sartoris@oats.inaf.it E-mail: borgani@oats.inaf.it E-mail: biviano@oats.inaf.it

    2013-06-01

    We perform a forecast analysis on how well a Euclid-like photometric galaxy cluster survey will constrain the total neutrino mass and effective number of neutrino species. We base our analysis on the Monte Carlo Markov Chains technique by combining information from cluster number counts and cluster power spectrum. We find that combining cluster data with Cosmic Microwave Background (CMB) measurements from Planck improves by more than an order of magnitude the constraint on neutrino masses compared to each probe used independently. For the ΛCDM+m{sub ν} model the 2σ upper limit on total neutrino mass shifts from Σm{sub ν} < 0.35 eV using cluster data alone to Σm{sub ν} < 0.031 eV when combined with Planck data. When a non-standard scenario with N{sub eff}≠3.046 number of neutrino species is considered, we estimate an upper limit of N{sub eff} < 3.14 (95%CL), while the bounds on neutrino mass are relaxed to Σm{sub ν} < 0.040 eV. This accuracy would be sufficient for a 2σ detection of neutrino mass even in the minimal normal hierarchy scenario (Σm{sub ν} ≅ 0.05 eV). In addition to the extended ΛCDM+m{sub ν}+N{sub eff} model we also consider scenarios with a constant dark energy equation of state and a non-vanishing curvature. When these models are considered the error on Σm{sub ν} is only slightly affected, while there is a larger impact of the order of ∼ 15% and ∼ 20% respectively on the 2σ error bar of N{sub eff} with respect to the standard case. To assess the effect of an uncertain knowledge of the relation between cluster mass and optical richness, we also treat the ΛCDM+m{sub ν}+N{sub eff} case with free nuisance parameters, which parameterize the uncertainties on the cluster mass determination. Adopting the over-conservative assumption of no prior knowledge on the nuisance parameter the loss of information from cluster number counts leads to a large degradation of neutrino constraints. In particular, the upper bounds for Σm{sub

  1. The mass function of IC 4665 revisited by the UKIDSS Galactic Clusters Survey

    NASA Astrophysics Data System (ADS)

    Lodieu, N.; de Wit, W.-J.; Carraro, G.; Moraux, E.; Bouvier, J.; Hambly, N. C.

    2011-08-01

    Context. Knowledge of the mass function in open clusters constitutes one way to constrain the formation of low-mass stars and brown dwarfs as does the knowledge of the frequency of multiple systems and the properties of disks. Aims: The aim of the project is to determine the shape of the mass function in the low-mass and substellar regimes in the pre-main sequence (27 Myr) cluster IC 4665, which is located at 350 pc from the Sun. Methods: We have cross-matched the near-infrared photometric data from the Eighth Data Release (DR8) of the UKIRT Infrared Deep Sky Survey (UKIDSS) Galactic Clusters Survey (GCS) with previous optical data obtained with the Canada-France-Hawaii (CFH) wide-field camera to improve the determination of the luminosity and mass functions in the low-mass and substellar regimes. Results: The availability of i and z photometry taken with the CFH12K camera on the Canada France Hawaii Telescope added strong constraints to the UKIDSS photometric selection in this cluster, which is located in a dense region of our Galaxy. We have derived the luminosity and mass functions of the cluster down to J = 18.5 mag, corresponding to masses of ~0.025 M⊙ at the distance and age of IC 4665 according to theoretical models. In addition, we have extracted new candidate members down to ~20 Jupiter masses in a previously unstudied region of the cluster. Conclusions: We have derived the mass function over the 0.6-0.04 M⊙ mass range and found that it is best represented by a log-normal function with a peak at 0.25-0.16 M⊙, consistent with the determination in the Pleiades. This work is based in part on data obtained as part of the UKIRT Infrared Deep Sky Survey. The United Kingdom Infrared Telescope is operated by the Joint Astronomy Centre on behalf of the Science and Technology Facilities Council of the UK.This work is partly based on observations obtained at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada

  2. Spectroscopic Confirmation of Two Massive Red-sequence-selected Galaxy Clusters at Z Approximately Equal to 1.2 in the Sparcs-North Cluster Survey

    NASA Technical Reports Server (NTRS)

    Muzzin, Adam; Wilson, Gillian; Yee, H.K.C.; Hoekstra, Henk; Gilbank, David; Surace, Jason; Lacy, Mark; Blindert, Kris; Majumdar, Subhabrata; Demarco, Ricardo; Gardner, Jonathan P.; Gladders, Mike; Lonsdale, Carol

    2008-01-01

    The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a deep z -band imaging survey covering the Spitzer SWIRE Legacy fields designed to create the first large homogeneously-selected sample of massive clusters at z > 1 using an infrared adaptation of the cluster red-sequence method. We present an overview of the northern component of the survey which has been observed with CFHT/MegaCam and covers 28.3 deg(sup 2). The southern component of the survey was observed with CTIO/MOSAICII, covers 13.6 deg(sup 2), and is summarized in a companion paper by Wilson et al. (2008). We also present spectroscopic confirmation of two rich cluster candidates at z approx. 1.2. Based on Nod-and- Shuffle spectroscopy from GMOS-N on Gemini there are 17 and 28 confirmed cluster members in SpARCS J163435+402151 and SpARCS J163852+403843 which have spectroscopic redshifts of 1.1798 and 1.1963, respectively. The clusters have velocity dispersions of 490 +/- 140 km/s and 650 +/- 160 km/s, respectively which imply masses (M(sub 200)) of (1.0 +/- 0.9) x 10(exp 14) Stellar Mass and (2.4 +/- 1.8) x 10(exp 14) Stellar Mass. Confirmation of these candidates as bonafide massive clusters demonstrates that two-filter imaging is an effective, yet observationally efficient, method for selecting clusters at z > 1.

  3. Massive open star clusters using the VVV survey. IV. WR 62-2, a new very massive star in the core of the VVV CL041 cluster

    NASA Astrophysics Data System (ADS)

    Chené, A.-N.; Ramírez Alegría, S.; Borissova, J.; O'Leary, E.; Martins, F.; Hervé, A.; Kuhn, M.; Kurtev, R.; Consuelo Amigo Fuentes, P.; Bonatto, C.; Minniti, D.

    2015-12-01

    Context. The ESO Public Survey VISTA Variables in the Vía Láctea (VVV) provides deep multi-epoch infrared observations for an unprecedented 562 sq. deg of the Galactic bulge and adjacent regions of the disk. Nearly 150 new open clusters and cluster candidates have been discovered in this survey. Aims: We present the fourth article in a series of papers focussed on young and massive clusters discovered in the VVV survey. This article is dedicated to the cluster VVV CL041, which contains a new very massive star candidate, WR 62-2. Methods: Following the methodology presented in the first paper of the series, wide-field, deep JHKs VVV observations, combined with new infrared spectroscopy, are employed to constrain fundamental parameters (distance, reddening, mass, age) of VVV CL041. Results: We confirm that the cluster VVV CL041 is a young (less than 4 Myr) and massive (3 ± 2 × 103 M⊙) cluster, and not a simple asterism. It is located at a distance of 4.2 ± 0.9 kpc, and its reddening is AV = 8.0 ± 0.2 mag, which is slightly lower than the average for the young clusters towards the centre of the Galaxy. Spectral analysis shows that the most luminous star of the cluster, of the WN8h spectral type, is a candidate to have an initial mass larger than 100 M⊙. Based on observations taken within the ESO VISTA Public Survey VVV, Programme ID 179.B-2002, and on observations with VLT/ISAAC at ESO (programme 087.D.0341A) and Flamingos-2 at Gemini (programme GS-2014A-Q-72).The photometric catalogue is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/584/A31

  4. A comprehensive ATCA survey for black holes in southern globular clusters

    NASA Astrophysics Data System (ADS)

    Miller-Jones, James; Maccarone, Tom; Chomiuk, Laura; Strader, Jay; Sivakoff, Gregory; Heinke, Craig; Shishkovsky, Laura; Huizenga, Danny

    2014-10-01

    Hundreds of stellar-mass black holes (BHs) are expected to form early in the lives of most globular star clusters (GCs), mass segregate to the cluster center, and largely be ejected through mutual gravitational interactions. Observations by our group have provided the first strong evidence for stellar-mass BHs in Galactic GCs. The key advance has been the use of radio continuum observations sensitive to BHs with low mass accretion rates. The existence of stellar-mass BHs in GCs would have broad implications: (i) GCs would become important hunting grounds for stellar-mass BHs; (ii) BHs in GCs would offer tests of the physics of low-luminosity accretion; (iii) GCs might offer a less biased view of the BH mass function than the field; and (iv) the prospects for detecting gravitational wave sources such as BH-BH or BH-pulsar binaries would be improved. The same radio observations can also reveal the presence of intermediate-mass black holes (IMBHs) in the centers of GCs, which could be detectable via their accretion signatures. Our radio observations have already placed the strongest limits to date on the presence of IMBHs in several Galactic GCs. We have begun a deep, systematic radio continuum survey for BHs in Galactic GCs. Here we propose to extend our successful ATCA pilot survey to all accessible and sufficiently massive southern clusters. With well-defined selection criteria, our sample will allow the first statistical determination of the presence of BHs in GCs.

  5. The Gaia-ESO Survey: membership and initial mass function of the γ Velorum cluster

    NASA Astrophysics Data System (ADS)

    Prisinzano, L.; Damiani, F.; Micela, G.; Jeffries, R. D.; Franciosini, E.; Sacco, G. G.; Frasca, A.; Klutsch, A.; Lanzafame, A.; Alfaro, E. J.; Biazzo, K.; Bonito, R.; Bragaglia, A.; Caramazza, M.; Vallenari, A.; Carraro, G.; Costado, M. T.; Flaccomio, E.; Jofré, P.; Lardo, C.; Monaco, L.; Morbidelli, L.; Mowlavi, N.; Pancino, E.; Randich, S.; Zaggia, S.

    2016-05-01

    Context. Understanding the properties of young open clusters, such as the initial mass function (IMF), star formation history, and dynamic evolution, is crucial for obtaining reliable theoretical predictions of the mechanisms involved in the star formation process. Aims: We want to obtain a list that is as complete as possible of confirmed members of the young open cluster γ Velorum, with the aim of deriving general cluster properties such as the IMF. Methods: We used all available spectroscopic membership indicators within the Gaia-ESO public archive, together with literature photometry and X-ray data, and for each method, we derived the most complete list of candidate cluster members. Then, we considered photometry, gravity, and radial velocities as necessary conditions for selecting a subsample of candidates whose membership was confirmed by using the lithium and Hα lines and X-rays as youth indicators. Results: We found 242 confirmed and 4 possible cluster members for which we derived masses using very recent stellar evolutionary models. The cluster IMF in the mass range investigated in this study shows a slope of α = 2.6 ± 0.5 for 0.5 Survey).Table 5 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/589/A70

  6. The XXL Survey . IV. Mass-temperature relation of the bright cluster sample

    NASA Astrophysics Data System (ADS)

    Lieu, M.; Smith, G. P.; Giles, P. A.; Ziparo, F.; Maughan, B. J.; Démoclès, J.; Pacaud, F.; Pierre, M.; Adami, C.; Bahé, Y. M.; Clerc, N.; Chiappetti, L.; Eckert, D.; Ettori, S.; Lavoie, S.; Le Fevre, J. P.; McCarthy, I. G.; Kilbinger, M.; Ponman, T. J.; Sadibekova, T.; Willis, J. P.

    2016-06-01

    Context. The XXL Survey is the largest survey carried out by XMM-Newton. Covering an area of 50 deg2, the survey contains ~450 galaxy clusters out to a redshift ~2 and to an X-ray flux limit of ~ 5 × 10-15 erg s-1 cm-2. This paper is part of the first release of XXL results focussed on the bright cluster sample. Aims: We investigate the scaling relation between weak-lensing mass and X-ray temperature for the brightest clusters in XXL. The scaling relation discussed in this article is used to estimate the mass of all 100 clusters in XXL-100-GC. Methods: Based on a subsample of 38 objects that lie within the intersection of the northern XXL field and the publicly available CFHTLenS shear catalog, we derive the weak-lensing mass of each system with careful considerations of the systematics. The clusters lie at 0.1 clusters from the literature, increasing the range to T ≃ 1-10 keV. To date, this is the largest sample of clusters with weak-lensing mass measurements that has been used to study the mass-temperature relation. Results: The mass-temperature relation fit (M ∝ Tb) to the XXL clusters returns a slope and intrinsic scatter σlnM|T≃ 0.53; the scatter is dominated by disturbed clusters. The fit to the combined sample of 96 clusters is in tension with self-similarity, b = 1.67 ± 0.12 and σlnM|T ≃ 0.41. Conclusions: Overall our results demonstrate the feasibility of ground-based weak-lensing scaling relation studies down to cool systems of ~1 keV temperature and highlight that the current data and samples are a limit to our statistical precision. As such we are unable to determine whether the validity of hydrostatic equilibrium is a function of halo mass. An enlarged sample of cool systems, deeper weak-lensing data, and robust modelling of the selection function will help to explore these issues further. Based on observations obtained with XMM-Newton, an ESA

  7. Massive and Distant Clusters of WISE Survey (MaDCoWS): Stellar Mass Fraction in IR-Selected Clusters at z ~ 1

    NASA Astrophysics Data System (ADS)

    Decker, Bandon; Brodwin, Mark

    2016-01-01

    Galaxy clusters are the largest gravitationally bound objects in the universe. In addition to being interesting objects to study in their own right, they are excellent laboratories in which to study galaxy evolution. Furthermore, the properties and abundance of galaxy clusters provide important tests for cosmology. Currently the South Pole Telescope (SPT) provides the largest catalog of high-redshift clusters selected through the Sunyaev-Zel'dovich (SZ) effect, which measures the pressure of the intracluster medium (ICM). The complementary Massive and Distant Clusters of WISE Survey (MaDCoWS) selects galaxy clusters on their stellar mass by identifying overdensities in the Wide Field Infrared Explorer (WISE) All-Sky Data release, which provides a selection independent to that of the SPT. We have followed up the most promising cluster candidates identified from MaDCoWS with Spitzer and the Combined Array for Research in Millimeter-wave Astronomy (CARMA) to get rest-frame H-band luminosities and radio observations of the SZ effect, respectively. Twelve clusters were robustly detected with CARMA with redshifts in the range 0.8 < z < 1.3 and total masses ranging from 2-10x1014 solar masses. Combining CARMA masses measured from the SZ observations with Spitzer/IRAC stellar masses, we determine the stellar mass fraction of the MaDCoWS sample of IR-selected clusters and compare with similar ICM-selected clusters from the SPT.

  8. The Massive and Distant Clusters of WISE Survey: MOO J1142+1527, a 1015 M⊙ Galaxy Cluster at z = 1.19

    NASA Astrophysics Data System (ADS)

    Gonzalez, Anthony H.; Decker, Bandon; Brodwin, Mark; Eisenhardt, Peter R. M.; Marrone, Daniel P.; Stanford, S. A.; Stern, Daniel; Wylezalek, Dominika; Aldering, Greg; Abdulla, Zubair; Boone, Kyle; Carlstrom, John; Fagrelius, Parker; Gettings, Daniel P.; Greer, Christopher H.; Hayden, Brian; Leitch, Erik M.; Lin, Yen-Ting; Mantz, Adam B.; Muchovej, Stephen; Perlmutter, Saul; Zeimann, Gregory R.

    2015-10-01

    We present confirmation of the cluster MOO J1142+1527, a massive galaxy cluster discovered as part of the Massive and Distant Clusters of WISE Survey. The cluster is confirmed to lie at z = 1.19, and using the Combined Array for Research in Millimeter-wave Astronomy we robustly detect the Sunyaev–Zel’dovich (SZ) decrement at 13.2σ. The SZ data imply a mass of M200m = (1.1 ± 0.2) × 1015M⊙, making MOO J1142+1527 the most massive galaxy cluster known at z > 1.15 and the second most massive cluster known at z > 1. For a standard ΛCDM cosmology it is further expected to be one of the ∼5 most massive clusters expected to exist at z ≥ 1.19 over the entire sky. Our ongoing Spitzer program targeting ∼1750 additional candidate clusters will identify comparably rich galaxy clusters over the full extragalactic sky.

  9. The Massive and Distant Clusters of WISE Survey. III. Sunyaev-Zel'dovich Masses of Galaxy Clusters at z˜1

    NASA Astrophysics Data System (ADS)

    Brodwin, M.; Greer, C. H.; Leitch, E. M.; Stanford, S. A.; Gonzalez, A. H.; Gettings, D. P.; Abdulla, Z.; Carlstrom, J. E.; Decker, B.; Eisenhardt, P. R.; Lin, H. W.; Mantz, A. B.; Marrone, D. P.; McDonald, M.; Stalder, B.; Stern, D.; Wylezalek, D.

    2015-06-01

    We present CARMA 30 GHz Sunyaev-Zel’dovich (SZ) observations of five high-redshift (z≳ 1), infrared-selected galaxy clusters discovered as part of the all-sky Massive and Distant Clusters of WISE Survey (MaDCoWS). The SZ decrements measured toward these clusters demonstrate that the MaDCoWS selection is discovering evolved, massive galaxy clusters with hot intracluster gas. Using the SZ scaling relation calibrated with South Pole Telescope clusters at similar masses and redshifts, we find these MaDCoWS clusters have masses in the range {{M}200}≈ 2-6× {{10}14} {{M}⊙ }. Three of these are among the most massive clusters found to date at z≳ 1, demonstrating that MaDCoWS is sensitive to the most massive clusters to at least z = 1.3. The added depth of the AllWISE data release will allow all-sky infrared cluster detection to z ≈ 1.5 and beyond.

  10. Hotspots of Malaria Transmission in the Peruvian Amazon: Rapid Assessment through a Parasitological and Serological Survey

    PubMed Central

    Rosas-Aguirre, Angel; Speybroeck, Niko; Llanos-Cuentas, Alejandro; Rosanas-Urgell, Anna; Carrasco-Escobar, Gabriel; Rodriguez, Hugo; Gamboa, Dionicia; Contreras-Mancilla, Juan; Alava, Freddy; Soares, Irene S.; Remarque, Edmond; D´Alessandro, Umberto; Erhart, Annette

    2015-01-01

    Background With low and markedly seasonal malaria transmission, increasingly sensitive tools for better stratifying the risk of infection and targeting control interventions are needed. A cross-sectional survey to characterize the current malaria transmission patterns, identify hotspots, and detect recent changes using parasitological and serological measures was conducted in three sites of the Peruvian Amazon. Material and Methods After full census of the study population, 651 participants were interviewed, clinically examined and had a blood sample taken for the detection of malaria parasites (microscopy and PCR) and antibodies against P. vivax (PvMSP119, PvAMA1) and P. falciparum (PfGLURP, PfAMA1) antigens by ELISA. Risk factors for malaria infection (positive PCR) and malaria exposure (seropositivity) were assessed by multivariate survey logistic regression models. Age-specific seroprevalence was analyzed using a reversible catalytic conversion model based on maximum likelihood for generating seroconversion rates (SCR, λ). SaTScan was used to detect spatial clusters of serology-positive individuals within each site. Results The overall parasite prevalence by PCR was low, i.e. 3.9% for P. vivax and 6.7% for P. falciparum, while the seroprevalence was substantially higher, 33.6% for P. vivax and 22.0% for P. falciparum, with major differences between study sites. Age and location (site) were significantly associated with P. vivax exposure; while location, age and outdoor occupation were associated with P. falciparum exposure. P. falciparum seroprevalence curves showed a stable transmission throughout time, while for P. vivax transmission was better described by a model with two SCRs. The spatial analysis identified well-defined clusters of P. falciparum seropositive individuals in two sites, while it detected only a very small cluster of P. vivax exposure. Conclusion The use of a single parasitological and serological malaria survey has proven to be an efficient