1,861 research outputs found
On the Presence of Thermal SZ Induced Signal in the First Year WMAP Temperature Maps
Using available optical and X-ray catalogues of clusters and superclusters of
galaxies, we build templates of tSZ emission as they should be detected by the
WMAP experiment. We compute the cross-correlation of our templates with WMAP
temperature maps, and interpret our results separately for clusters and for
superclusters of galaxies. For clusters of galaxies, we claim 2-5
detections in our templates built from BCS Ebeling et al. (1998), NORAS
(Boehringer et al. 2000) and de Grandi et al. (1999) catalogues. In these
templates, the typical cluster temperature decrements in WMAP maps are around
15-35 K in the RJ range (no beam deconvolution applied). Several tests
probing the possible influence of foregrounds in our analyses demonstrate that
our results are robust against galactic contamination. On supercluster scales,
we detect a diffuse component in the V & W WMAP bands which cannot be generated
by superclusters in our catalogues (Einasto et al. 1994, 1997), and which is
not present in the clean map of Tegmark, de Oliveira-Costa & Hamilton (2003).
Using this clean map, our analyses yield, for Einasto's supercluster
catalogues, the following upper limit for the comptonization parameter
associated to supercluster scales: y_{SC} < 2.18 \time s 10^{-8} at the 95%
confidence limit.Comment: MNRAS accepted. New section and minor changes include
Limits on Hot Intracluster Gas Contributions to the Tenerife Temperature Anisotropy Map
We limit the contribution of the hot intracluster gas, by means of the
Sunyaev-Zel'dovich effect, to the temperature anisotropies measured by the
Tenerife experiment. The data is cross-correlated with maps generated from the
ACO cluster catalogue, the ROSAT PSPC catalogue of clusters of galaxies, a
catalogue of superclusters and the HEAO 1 A-1 map of X-ray sources. There is no
evidence of contamination by such sources at an rms level of K at
99% confidence level at angular resolution. We place an upper limit on
the mean Comptonization parameter of at the same
level of confidence. These limits are slightly more restrictive than those
previously found by a similar analysis on the COBE/DMR data and indicate that
most of the signal measured by Tenerife is cosmological.Comment: To be published in ApJ (main journal
The origin of the LMC stellar bar: clues from the SFH of the bar and inner disk
We discuss the origin of the LMC stellar bar by comparing the star formation
histories (SFH) obtained from deep color-magnitude diagrams (CMDs) in the bar
and in a number of fields in different directions within the inner disk. The
CMDs, reaching the oldest main sequence turnoffs in these very crowded fields,
have been obtained with VIMOS on the VLT in service mode, under very good
seeing conditions. We show that the SFHs of all fields share the same patterns,
with consistent variations of the star formation rate as a function of time in
all of them. We therefore conclude that no specific event of star formation can
be identified with the formation of the LMC bar, which instead likely formed
from a redistribution of disk material that occurred when the LMC disk became
bar unstable, and shared a common SFH with the inner disk thereafter. The
strong similarity between the SFH of the center and edge of the bar rules out
significant spatial variations of the SFH across the bar, which are predicted
by scenarios of classic bar formation through buckling mechanisms.Comment: MNRAS Letters, accepte
Determinación de la estructura genética de las poblaciones silvestres españolas de Castanea sativa mediante isoenzimas
The genetic variability within and among 17 wild Spanish chestnut stands was examined by isozyme analysis, with the goals of describing their geographic structure and designing conservation and management strategies. Measures of genetic diversity such as allelic richness, heterozygosity, polymorphism, F-statistics, D-statistics, gene flow, clustering using Nei’s genetic distances and a method based on an Monte Carlo Markov Chain algorithm and the contributions of each stand to diversity and allelic richness were all used. Wild Spanish chestnut populations displayed heterogeneity of allele frequencies between them, high levels of genetic diversity and high differentiation (Fst = 0.15) compared with populations from other western European countries such as France and Italy. The two clustering methods allowed the identification of three clusters: a Mediterranean cluster, a northern Spanish cluster and the southern Galician cluster. The highest heterozygosity and allelic richness were found in the North, especially in the southern Galician cluster. Several areas can be recommended for inclusion in the network of Conservation Units: Fraga de Catasós, representing the southern Galician cluster; Fragas do Eume, representing the northern Spanish cluster; and Hervás or El Tiemblo, representing the Mediterranean cluster.La variabilidad genética entre y dentro de 17 rodales de castaño silvestre muestreados en poblaciones españolas se examinó mediante el análisis de polimorfismos isoenzimáticos con la finalidad de describir la estructura geográfica y diseñar estrategias de conservación y manejo. Se calcularon la riqueza alélica, heterocigosidad, polimorfismo, la estadística F y D, el flujo genético y se realizaron análisis de agrupación de poblaciones utilizando la distancia genética de Nei y un método basado en el algoritmo Monte Carlo Markov Chain, y finalmente se calcularon las contribuciones de cada rodal a la diversidad y riqueza alélica.
Las poblaciones silvestres de castaño españolas presentaron heterogeneidad de frecuencias alélicas entre ellas, elevados niveles de diversidad genética y de diferenciación (Fst = 0.15) comparadas con otras poblaciones del Oeste de Europa. Se identificaron tres grupos de poblaciones: el grupo Mediterráneo, el grupo del Norte y del Sur de Galicia. La mayor heterocigosidad y riqueza alélica está en el Norte, principalmente en el grupo del Sur de Galicia. Se recomiendan varias áreas para incluir en la red de Unidades de Conservación: Fraga de Catasós, en representación del grupo Sur de Galicia; las Fragas do Eume, representando el grupo del Norte; y Hervás o el Tiemblo en representación del grupo Mediterráneo
On the Number Density of Sunyaev-Zel'dovich Clusters of Galaxies
If the mean properties of clusters of galaxies are well described by the
entropy-driven model, the distortion induced by the cluster population on the
blackbody spectrum of the Cosmic Microwave Background radiation is proportional
to the total amount of intracluster gas while temperature anisotropies are
dominated by the contribution of clusters of about 10^{14} solar masses. This
result depends marginally on cluster parameters and it can be used to estimate
the number density of clusters with enough hot gas to produce a detectable
Sunyaev-Zel'dovich effect. Comparing different cosmological models, the
relation depends mainly on the density parameter Omega_m. If the number density
of clusters could be estimated by a different method, then this dependence
could be used to constrain Omega_m.Comment: 8 pages, 3 figures, submitted to ApJ Letter
Tomography of the Reionization Epoch with Multifrequency CMB Observations
We study the constraints that future multifrequency Cosmic Microwave
Background (CMB) experiments will be able to set on the metal enrichment
history of the Inter Galactic Medium at the epoch of reionisation. We forecast
the signal to noise ratio for the detection of the signal introduced in the CMB
by resonant scattering off metals at the end of the Dark Ages. We take into
account systematics associated to inter-channel calibration, PSF reconstruction
errors and innacurate foreground removal. We develop an algorithm to optimally
extract the signal generated by metals during reionisation and to remove
accurately the contamination due to the thermal Sunyaev-Zel'dovich effect.
Although demanding levels of foreground characterisation and control of
systematics are required, they are very distinct from those encountered in
HI-21cm studies and CMB polarization, and this fact encourages the study of
resonant scattering off metals as an alternative way of conducting tomography
of the reionisation epoch. An ACT-like experiment with optimistic assumtions on
systematic effects, and looking at clean regions of the sky, can detect changes
of 3%-12% (95% c.l.) of the OIII abundance (with respect its solar value) in
the redshift range [12,22], for reionization redshift .
However, for , it can only set upper limits on NII abundance
increments of 60% its solar value in the redshift range [5.5,9],
(95% c.l.). These constraints assume that inter-channel calibration is accurate
down to one part in , which constitutes the most critical technical
requirement of this method, but still achievable with current technology.Comment: 10 pages, 2 figures, submitted to Astrophysical Journal. Comments are
welcom
Evidence of the missing baryons from the kinematic Sunyaev-Zeldovich effect in Planck data
Under the terms of the Creative Commons Attribution license.-- et al.We estimate the amount of the missing baryons detected by the Planck measurements of the cosmic microwave background in the direction of central galaxies (CGs) identified in the Sloan galaxy survey. The peculiar motion of the gas inside and around the CGs unveils values of the Thomson optical depth τT in the range 0.2-2×10-4, indicating that the regions probed around CGs contain roughly half of the total amount of baryons in the Universe at the epoch where the CGs are found. If baryons follow dark matter, the measured τT's are compatible with the detection of all of the baryons existing inside and around the CGs.C. H.-M. acknowledges the support of Ramón y Cajal Fellowship No. RyC-2011-08262, Marie Curie Career Integration Grant No. 294183, and Spanish Ministerio de Economía y Competitividad Project No. AYA2012-30789. Y.-Z. M thanks ERC for its support through Starting Grant No. 307209.Peer Reviewe
Relationships between school anxiety, trait anxiety, state anxiety and depression in a sample of Spanish adolescents
Diferentes estudios han analizado la ansiedad escolar como un constructo unitario sin atender a las diferentes situaciones y sistemas de respuesta que conforman este constructo. El presente estudio considera la ansiedad escolar como un constructo multidimensional y su objetivo fue analizar las relaciones y capacidad predictiva de las situaciones y sistemas de respuesta de la ansiedad escolar sobre la ansiedad rasgo, la ansiedad estado y la depresión. El Inventario de Ansiedad Escolar (IAES), el Inventario de Ansiedad Estado-Rasgo (STAI y STAIC) y el Inventario de Depresión Infantil (CDI) fueron administrados a una muestra de 1409 estudiantes españoles de 12 a 18 años de edad. Los resultados muestran correlaciones positivas y significativas entre las situaciones y respuestas de ansiedad escolar con ansiedad rasgo, ansiedad estado y depresión. Además, la mayoría de factores situacionales y sistemas de respuesta de la ansiedad escolar son predictores significativos y positivos de la ansiedad rasgo, la ansiedad estado y la depresión. Las implicaciones prácticas de estos resultados son discutidas.Different studies have analyzed school anxiety as a unitary construct, without regard to the different situations and response systems that make up this construct. However, the present study considers the school anxiety as a multidimensional construct. Thus, the aim of this study was to analyze the relationships and predictive capacity among situations and responses of school anxiety on trait anxiety, state anxiety and depression. The School Anxiety Inventory (IAES), the State Trait Anxiety Inventory (STAI and STAIC) and the Child Depression Inventory (CDI) were administered to a sample of 1,409 Spanish students of 12 to 18 years. The results show significant and positive correlations between situations and responses of school anxiety with trait anxiety, state anxiety and depression. In addition, situations and responses systems of school anxiety are significant and positive predictors of trait anxiety, state anxiety and depression. The practical implications of these findings are discussed
Optimal management of the Jucar River and Turia River basins under uncertain drought conditions
This paper presents a methodology to assess the best behavior achievable for a water resources system, and we apply it to the joint system of the Jucar River and Turia River basins in Spain. The resources of the two rivers are used jointly to meet the different water uses within the region, especially urban demands and environmental requirements. The climate change effects in this area are predicted to be particularly severe in this area with great variability in drought patterns. The results are particularly suitable for evaluating the best performance of the system under uncertain conditions
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