The Experts below are selected from a list of 56313 Experts worldwide ranked by ideXlab platform
S Borgani - One of the best experts on this subject based on the ideXlab platform.
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a chandra archival study of the temperature and metal abundance Profiles in hot galaxy Clusters at 0 1 z 0 3
The Astrophysical Journal, 2007Co-Authors: A Baldi, S Ettori, P Mazzotta, P Tozzi, S BorganiAbstract:We present an analysis of the temperature and metallicity Profiles of 12 galaxy Clusters in the redshift range 0.1-0.3 selected from the Chandra archive with at least ~20,000 net ACIS counts and kT > 6 keV. We divide the sample between seven cooling-core (CC) and five non-cooling-core (NCC) Clusters according to their central cooling time. We find that single power laws can properly describe both the temperature and metallicity Profiles at radii larger than 0.1r180 in both CC and NCC systems, with NCC objects showing steeper Profiles outward. A significant deviation is present only in the inner 0.1r180. We perform a comparison of our sample with the De Grandi & Molendi BeppoSAX sample of local CC and NCC Clusters, finding a complete agreement in the CC Cluster Profile and a marginally higher value (at ~1 σ) in the inner regions of the NCC Clusters. The slope of the power law describing kT(r) within 0.1r180 correlates strongly with the ratio between the cooling time and the age of the universe at the Cluster redshift, with a slope >0 and τc/τage 0.6 in CC systems.
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a chandra archival study of the temperature and metal abundance Profiles in hot galaxy Clusters at 0 1 z 0 3
arXiv: Astrophysics, 2007Co-Authors: A Baldi, S Ettori, P Mazzotta, P Tozzi, S BorganiAbstract:We present the analysis of the temperature and metallicity Profiles of 12 galaxy Clusters in the redshift range 0.1--0.3 selected from the Chandra archive with at least ~20,000 net ACIS counts and kT>6 keV. We divide the sample between 7 Cooling-Core (CC) and 5 Non-Cooling-Core (NCC) Clusters according to their central cooling time. We find that single power-laws can describe properly both the temperature and metallicity Profiles at radii larger than 0.1 r_180 in both CC and NCC systems, showing the NCC objects steeper Profiles outwards. A significant deviation is only present in the inner 0.1 r_180. We perform a comparison of our sample with the De Grandi & Molendi BeppoSAX sample of local CC and NCC Clusters, finding a complete agreement in the CC Cluster Profile and a marginally higher value (at ~1sigma) in the inner regions of the NCC Clusters. The slope of the power-law describing kT(r) within 0.1 r_180 correlates strongly with the ratio between the cooling time and the age of the Universe at the Cluster redshift, being the slope >0 and tau_c/tau_age<=0.6 in CC systems.
Thomas F. Meyer - One of the best experts on this subject based on the ideXlab platform.
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Gene expression Profiles of Chlamydophila pneumoniae during the developmental cycle and iron depletion-mediated persistence
2016Co-Authors: Andre ́ P. Mäurer, Hans J. Mollenkopf, Thomas F. MeyerAbstract:The obligate intracellular, gram-negative bacterium Chlamydophila pneumoniae (Cpn) has impact as a human pathogen. Little is known about changes in the Cpn transcriptome during its biphasic developmental cycle (the acute infection) and persistence. The latter stage has been linked to chronic diseases. To analyze Cpn CWL029 gene expression, we designed a pathogen-specific oligo microarray and optimized the extraction method for pathogen RNA. Throughout the acute infection, ratio expression Profiles for each gene were generated using 48 h post infection as a reference. Based on these Profiles, significantly expressed genes were separated into 12 expression Clusters using self-organizing map Clustering and manual sorting into the ‘‘early’’, ‘‘mid’’, ‘‘late’’, and ‘‘tardy’ ’ Cluster classes. The latter two were differentiated because the ‘‘tardy’ ’ class showed steadily increasing expression at the end of the cycle. The transcriptome of the Cpn elementary body (EB) and published EB proteomics data were compared to the Cluster Profile of the acute infection. We found an intriguing association between ‘‘late’ ’ genes and genes coding for EB proteins, whereas ‘‘tardy’ ’ genes were mainly associated with genes coding for EB mRNA. It has been published that iron depletion leads to Cpn persistence. We compared the gene expression Profiles during iron depletion–mediated persistence with the expression Clusters of the acute infection. This led to the finding that establishment of iron depletion–mediated persistence is more likely a mid-cycle arrest in development rather than a completely distinct gene expression pattern. Here, we describe the Cpn transcriptome during the acute infection, differentiating ‘‘late’ ’ genes
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Gene expression Profiles of Chlamydophila pneumoniae during the developmental cycle and iron depletion-mediated persistence
PLoS pathogens, 2007Co-Authors: André P. Mäurer, Adrian Mehlitz, Hans J. Mollenkopf, Thomas F. MeyerAbstract:The obligate intracellular, gram-negative bacterium Chlamydophila pneumoniae (Cpn) has impact as a human pathogen. Little is known about changes in the Cpn transcriptome during its biphasic developmental cycle (the acute infection) and persistence. The latter stage has been linked to chronic diseases. To analyze Cpn CWL029 gene expression, we designed a pathogen-specific oligo microarray and optimized the extraction method for pathogen RNA. Throughout the acute infection, ratio expression Profiles for each gene were generated using 48 h post infection as a reference. Based on these Profiles, significantly expressed genes were separated into 12 expression Clusters using self-organizing map Clustering and manual sorting into the “early”, “mid”, “late”, and “tardy” Cluster classes. The latter two were differentiated because the “tardy” class showed steadily increasing expression at the end of the cycle. The transcriptome of the Cpn elementary body (EB) and published EB proteomics data were compared to the Cluster Profile of the acute infection. We found an intriguing association between “late” genes and genes coding for EB proteins, whereas “tardy” genes were mainly associated with genes coding for EB mRNA. It has been published that iron depletion leads to Cpn persistence. We compared the gene expression Profiles during iron depletion–mediated persistence with the expression Clusters of the acute infection. This led to the finding that establishment of iron depletion–mediated persistence is more likely a mid-cycle arrest in development rather than a completely distinct gene expression pattern. Here, we describe the Cpn transcriptome during the acute infection, differentiating “late” genes, which correlate to EB proteins, and “tardy” genes, which lead to EB mRNA. Expression Profiles during iron mediated–persistence led us to propose the hypothesis that the transcriptomic “clock” is arrested during acute mid-cycle.
Stella Seitz - One of the best experts on this subject based on the ideXlab platform.
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optimizing weak lensing mass estimates for Cluster Profile uncertainty
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Daniel Gruen, Tsz Yan Lam, G M Bernstein, Stella SeitzAbstract:Weak lensing measurements of Cluster masses are necessary for calibrating mass-observable relations (MORs) to investigate the growth of structure and the properties of dark energy. However, the measured Cluster shear signal varies at fixed massM200m due to inherent ellipticity of background galaxies, intervening structures along the line of sight and variations in the Cluster structure due to scatter in concentrations, asphericity and substructure. We use N-body simulated haloes to derive and evaluate a weak lensing circular aperture mass measurement Map that minimizes the mass estimate variance � (Map − M200m) 2 � in the presence of all these forms of variability. Depending on halo mass and observational conditions, the resulting mass estimator improves on Map filters optimized for circular NFW-Profile Clusters in the presence of uncorrelated large-scale structure (LSS) about as much as the latter improve on an estimator that only minimizes the influence of shape noise. Optimizing for uncorrelated LSS while ignoring the variation of internal Cluster structure puts too much weight on the Profile near the cores of haloes, and under some circumstances can even be worse than not accounting for LSS at all. We briefly discuss the impact of variability in Cluster structure and correlated structures on the design and performance of weak lensing surveys intended to calibrate Cluster MORs.
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Optimizing weak lensing mass estimates for Cluster Profile uncertainty
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Daniel Gruen, Gary Bernstein, Tsz Yan Lam, Stella SeitzAbstract:Weak lensing measurements of Cluster masses are necessary for calibrating mass-observable relations (MORs) to investigate the growth of structure and the properties of dark energy. However, the measured Cluster shear signal varies at fixed mass M_200m due to inherent ellipticity of background galaxies, intervening structures along the line of sight, and variations in the Cluster structure due to scatter in concentrations, asphericity and substructure. We use N-body simulated halos to derive and evaluate a weak lensing circular aperture mass measurement M_ap that minimizes the mass estimate variance in the presence of all these forms of variability. Depending on halo mass and observational conditions, the resulting mass estimator improves on M_ap filters optimized for circular NFW-Profile Clusters in the presence of uncorrelated large scale structure (LSS) about as much as the latter improve on an estimator that only minimizes the influence of shape noise. Optimizing for uncorrelated LSS while ignoring the variation of internal Cluster structure puts too much weight on the Profile near the cores of halos, and under some circumstances can even be worse than not accounting for LSS at all. We briefly discuss the impact of variability in Cluster structure and correlated structures on the design and performance of weak lensing surveys intended to calibrate Cluster MORs.
Daniel Gruen - One of the best experts on this subject based on the ideXlab platform.
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optimizing weak lensing mass estimates for Cluster Profile uncertainty
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Daniel Gruen, Tsz Yan Lam, G M Bernstein, Stella SeitzAbstract:Weak lensing measurements of Cluster masses are necessary for calibrating mass-observable relations (MORs) to investigate the growth of structure and the properties of dark energy. However, the measured Cluster shear signal varies at fixed massM200m due to inherent ellipticity of background galaxies, intervening structures along the line of sight and variations in the Cluster structure due to scatter in concentrations, asphericity and substructure. We use N-body simulated haloes to derive and evaluate a weak lensing circular aperture mass measurement Map that minimizes the mass estimate variance � (Map − M200m) 2 � in the presence of all these forms of variability. Depending on halo mass and observational conditions, the resulting mass estimator improves on Map filters optimized for circular NFW-Profile Clusters in the presence of uncorrelated large-scale structure (LSS) about as much as the latter improve on an estimator that only minimizes the influence of shape noise. Optimizing for uncorrelated LSS while ignoring the variation of internal Cluster structure puts too much weight on the Profile near the cores of haloes, and under some circumstances can even be worse than not accounting for LSS at all. We briefly discuss the impact of variability in Cluster structure and correlated structures on the design and performance of weak lensing surveys intended to calibrate Cluster MORs.
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Optimizing weak lensing mass estimates for Cluster Profile uncertainty
Monthly Notices of the Royal Astronomical Society, 2011Co-Authors: Daniel Gruen, Gary Bernstein, Tsz Yan Lam, Stella SeitzAbstract:Weak lensing measurements of Cluster masses are necessary for calibrating mass-observable relations (MORs) to investigate the growth of structure and the properties of dark energy. However, the measured Cluster shear signal varies at fixed mass M_200m due to inherent ellipticity of background galaxies, intervening structures along the line of sight, and variations in the Cluster structure due to scatter in concentrations, asphericity and substructure. We use N-body simulated halos to derive and evaluate a weak lensing circular aperture mass measurement M_ap that minimizes the mass estimate variance in the presence of all these forms of variability. Depending on halo mass and observational conditions, the resulting mass estimator improves on M_ap filters optimized for circular NFW-Profile Clusters in the presence of uncorrelated large scale structure (LSS) about as much as the latter improve on an estimator that only minimizes the influence of shape noise. Optimizing for uncorrelated LSS while ignoring the variation of internal Cluster structure puts too much weight on the Profile near the cores of halos, and under some circumstances can even be worse than not accounting for LSS at all. We briefly discuss the impact of variability in Cluster structure and correlated structures on the design and performance of weak lensing surveys intended to calibrate Cluster MORs.
André P. Mäurer - One of the best experts on this subject based on the ideXlab platform.
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Gene expression Profiles of Chlamydophila pneumoniae during the developmental cycle and iron depletion-mediated persistence
PLoS pathogens, 2007Co-Authors: André P. Mäurer, Adrian Mehlitz, Hans J. Mollenkopf, Thomas F. MeyerAbstract:The obligate intracellular, gram-negative bacterium Chlamydophila pneumoniae (Cpn) has impact as a human pathogen. Little is known about changes in the Cpn transcriptome during its biphasic developmental cycle (the acute infection) and persistence. The latter stage has been linked to chronic diseases. To analyze Cpn CWL029 gene expression, we designed a pathogen-specific oligo microarray and optimized the extraction method for pathogen RNA. Throughout the acute infection, ratio expression Profiles for each gene were generated using 48 h post infection as a reference. Based on these Profiles, significantly expressed genes were separated into 12 expression Clusters using self-organizing map Clustering and manual sorting into the “early”, “mid”, “late”, and “tardy” Cluster classes. The latter two were differentiated because the “tardy” class showed steadily increasing expression at the end of the cycle. The transcriptome of the Cpn elementary body (EB) and published EB proteomics data were compared to the Cluster Profile of the acute infection. We found an intriguing association between “late” genes and genes coding for EB proteins, whereas “tardy” genes were mainly associated with genes coding for EB mRNA. It has been published that iron depletion leads to Cpn persistence. We compared the gene expression Profiles during iron depletion–mediated persistence with the expression Clusters of the acute infection. This led to the finding that establishment of iron depletion–mediated persistence is more likely a mid-cycle arrest in development rather than a completely distinct gene expression pattern. Here, we describe the Cpn transcriptome during the acute infection, differentiating “late” genes, which correlate to EB proteins, and “tardy” genes, which lead to EB mRNA. Expression Profiles during iron mediated–persistence led us to propose the hypothesis that the transcriptomic “clock” is arrested during acute mid-cycle.