Showing papers by "DSM published in 2011"

CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey

Abstract: The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, from z approx. 8 - 1.5. It will image > 250,000 distant galaxies using three separate cameras on the Hubble Space Tele8cope, from the mid-UV to near-IR, and will find and measure Type Ia supernovae beyond z > 1.5 to test their accuracy as standard candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10(exp 9) solar mass to z approx. 2, reaching the knee of the UV luminosity function of galaxies to z approx. 8. The survey covers approximately 800 square arc minutes and is divided into two parts. The CANDELS/Deep survey (5(sigma) point-source limit H =27.7mag) covers approx. 125 square arcminutes within GOODS-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (EGS, COSMOS, and UDS) and covers the full area to a 50(sigma) point-source limit of H ? or approx. = 27.0 mag. Together with the Hubble Ultradeep Fields, the strategy creates a three-tiered "wedding cake" approach that has proven efficient for extragalactic surveys. Data from the survey are non-proprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design.

Candels: The cosmic assembly near-infrared deep extragalactic legacy survey - The hubble space telescope observations, imaging data products, and mosaics

Abstract: This paper describes the Hubble Space Telescope imaging data products and data reduction procedures for the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). This survey is designed to document the evolution of galaxies and black holes at z 1.5-8, and to study Type Ia supernovae at z > 1.5. Five premier multi-wavelength sky regions are selected, each with extensive multi-wavelength observations. The primary CANDELS data consist of imaging obtained in the Wide Field Camera 3 infrared channel (WFC3/IR) and the WFC3 ultraviolet/optical channel, along with the Advanced Camera for Surveys (ACS). The CANDELS/Deep survey covers ~125 arcmin2 within GOODS-N and GOODS-S, while the remainder consists of the CANDELS/Wide survey, achieving a total of ~800 arcmin2 across GOODS and three additional fields (Extended Groth Strip, COSMOS, and Ultra-Deep Survey). We summarize the observational aspects of the survey as motivated by the scientific goals and present a detailed description of the data reduction procedures and products from the survey. Our data reduction methods utilize the most up-to-date calibration files and image combination procedures. We have paid special attention to correcting a range of instrumental effects, including charge transfer efficiency degradation for ACS, removal of electronic bias-striping present in ACS data after Servicing Mission 4, and persistence effects and other artifacts in WFC3/IR. For each field, we release mosaics for individual epochs and eventual mosaics containing data from all epochs combined, to facilitate photometric variability studies and the deepest possible photometry. A more detailed overview of the science goals and observational design of the survey are presented in a companion paper.

Design concepts for the Cherenkov Telescope Array CTA: An advanced facility for ground-based high-energy gamma-ray astronomy

Abstract: Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.

Low-platinum and platinum-free catalysts for the oxygen reduction reaction at fuel cell cathodes

Abstract: Fuel cell reactions invariably involve an oxygen reduction reaction (ORR) at the cathode, which is one of the main rate-decreasing steps on platinum (Pt)-catalysts in the water formation reaction and energy conversion efficiency in polymer electrolyte membrane fuel cells (PEMFCs). The Pt scarcity and cost have led to the development of alternative catalyst materials for fuel cell applications. This paper reviews ORR catalysts with regard to their classification, mechanism, activity and performances. From conventional Pt-based catalysts to non-noble metal or bio-inspired catalysts, we show how significant progresses were made in ORR catalysis.

The MCXC: a meta-catalogue of x-ray detected clusters of galaxies

Abstract: We present the compilation and properties of a meta-catalogue of X-ray detected clusters of galaxies, the MCXC. This very large catalogue is based on publicly available ROSAT All Sky Survey-based (NORAS, REFLEX, BCS, SGP, NEP, MACS, and CIZA) and serendipitous (160SD, 400SD, SHARC, WARPS, and EMSS) cluster catalogues. Data have been systematically homogenised to an overdensity of 500, and duplicate entries from overlaps between the survey areas of the individual input catalogues are carefully handled. The MCXC comprises 1743 clusters with virtually no duplicate entries. For each cluster the MCXC provides three identifiers, a redshift, coordinates, membership in the original catalogue, and standardised 0.1−2.4 keV band luminosity L500 ,t otal massM500, and radius R500. The meta-catalogue additionally furnishes information on overlaps between the input catalogues and the luminosity ratios when measurements from different surveys are available, and gives notes on individual objects. The MCXC is available in electronic format for maximum usefulness in X-ray, SZ, and other multiwavelength studies.

Planck early results. XIX. All-sky temperature and dust optical depth from Planck and IRAS. Constraints on the "dark gas" in our Galaxy

Abstract: An all sky map of the apparent temperature and optical depth of thermal dust emission is constructed using the Planck-HFI (350μm to 2 mm) andIRAS(100μm) data. The optical depth maps are correlated with tracers of the atomic (Hi) and molecular gas traced by CO. The correlation with the column density of observed gas is linear in the lowest column density regions at high Galactic latitudes. At high N(H), the correlation is consistent with that of the lowest NH, for a given choice of the CO-to-H(2) conversion factor. In the intermediate NH range, a departure from linearity is observed, with the dust optical depth in excess of the correlation. This excess emission is attributed to thermal emission by dust associated with a dark gas phase, undetected in the available Hi and CO surveys. The 2D spatial distribution of the dark gas in the solar neighbourhood (|b(II)| > 10°) is shown to extend around known molecular regions traced by CO. The average dust emissivity in the Hi phase in the solar neighbourhood is found to be τ(D)/N(H)(tot) = 5.2×10(-26) cm(2) at 857 GHz. It follows roughly a power law distribution with a spectral index β = 1.8 all the way down to 3 mm, although the SED flattens slightly in the millimetre. Taking into account the spectral shape of the dust optical depth, the emissivity is consistent with previous values derived fromFIRAS measurements at high latitudes within 10%. The threshold for the existence of the dark gas is found at N(H)(tot) = (8.0±0.58)×10(20) H cm(−2) (A(V )= 0.4mag). Assuming the same high frequency emissivity for the dust in the atomic and the molecular phases leads to an average X(CO) = (2.54 ± 0.13) × 10(20) H(2) cm(-2)/(K km s(-1)). The mass of dark gas is found to be 28% of the atomic gas and 118% of the CO emitting gas in the solar neighbourhood. The Galactic latitude distribution shows that its mass fraction is relatively constant down to a few degrees from the Galactic plane. A possible explanation for the dark gas lies in a dark molecular phase, where H2 survives photodissociation but CO does not. The observed transition for the onsetof this phase in the solar neighbourhood (AV = 0.4mag) appears consistent with recent theoretical predictions. It is also possible that up to half of the dark gas could be in atomic form, due to optical depth effects in the Hi measurements.

Planck early results - VIII. The all-sky early Sunyaev-Zeldovich cluster sample

Abstract: We present the first all-sky sample of galaxy clusters detected blindly by the Planck satellite through the Sunyaev-Zeldovich (SZ) effect from its six highest frequencies. This early SZ (ESZ) sample is comprised of 189 candidates, which have a high signal-to-noise ratio ranging from 6 to 29. Its high reliability (purity above 95%) is further ensured by an extensive validation process based on Planck internal quality assessments and by external cross-identification and follow-up observations. Planck provides the first measured SZ signal for about 80% of the 169 previouslyknown ESZ clusters. Planck furthermore releases 30 new cluster candidates, amongst which 20 meet the ESZ signal-to-noise selection criterion. At the submission date, twelve of the 20 ESZ candidates were confirmed as new clusters, with eleven confirmed using XMM-Newton snapshot observations, most of them with disturbed morphologies and low luminosities. The ESZ clusters are mostly at moderate redshifts (86% with z below 0.3) and span more than a decade in mass, up to the rarest and most massive clusters with masses above 1 × 10 15 M� .

Charged-particle multiplicities in pp interactions measured with the ATLAS detector at the LHC

Abstract: Measurements are presented from proton-proton collisions at centre-of-mass energies of root s = 0.9, 2.36 and 7 TeV recorded with the ATLAS detector at the LHC. Events were collected using a single-arm minimum-bias trigger. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transverse momentum and charged-particle multiplicity are measured. Measurements in different regions of phase space are shown, providing diffraction-reduced measurements as well as more inclusive ones. The observed distributions are corrected to well-defined phase-space regions, using model-independent corrections. The results are compared to each other and to various Monte Carlo (MC) models, including a new AMBT1 pythia6 tune. In all the kinematic regions considered, the particle multiplicities are higher than predicted by the MC models. The central charged-particle multiplicity per event and unit of pseudorapidity, for tracks with p(T) > 100 MeV, is measured to be 3.483 +/- 0.009 (stat) +/- 0.106 (syst) at root s = 0.9 TeV and 5.630 +/- 0.003 (stat) +/- 0.169 (syst) at root s = 7 TeV.

Caprolactam from Renewable Resources: Catalytic Conversion of 5-Hydroxymethylfurfural into Caprolactone

Abstract: Renewable nylon: 5-Hydroxymethylfurfural (HMF), which can be obtained from renewable resources such as D-fructose, was converted into caprolactone with very good overall selectivity in only three steps. The new route involves two hydrogenation steps to obtain 1,6-hexanediol, which was oxidatively cyclized to caprolactone, and then converted into caprolactam.

Colloids and the Depletion Interaction

Abstract: Preface 1 Introduction 1.1 Colloidal interactions 1.2 The Von Guericke force 1.3 Depletion 1.4 Manifestations of depletion effects in colloid + polymer mixtures 1.5 Historical overview on depletion 1.5.1 Experimental observations before the 1950s 1.5.2 Attractive forces in Nagoya 1.5.3 Systematic studies after AO 1.6 Outline of this book 2 Depletion Interaction 2.1 Depletion interaction due to penetrable spheres 2.1.1 Depletion interaction between two flat plates 2.1.2 Depletion interaction between two spheres 2.2 Depletion interaction due to ideal polymers 2.2.1 Depletion interaction between two flat plates 2.2.2 Interaction between two spheres 2.3 Depletion interaction due to excluded volume polymers 2.3.1 Characteristic length scales in polymer solutions 2.3.2 Osmotic pressure of polymer solutions 2.3.3 Depletion thickness due to excluded volume polymers 2.3.4 Evaluation of the depletion interaction due to excluded volume polymers 2.4 Depletion interaction due to spheres 2.4.1 Concentration profiles near a hard wall and between two hard walls 2.4.2 Depletion interaction between two flat plates 2.4.3 Depletion interaction between two (big) spheres 2.5 Depletion interaction due to rods 2.5.1 Depletion interaction between two flat plates 2.5.2 Interaction between two (big) colloidal spheres using the Derjaguin approximation 2.6 Depletion interaction due to disks 2.6.1 Depletion interaction between two flat plates 2 .6.2 Interaction bet ween two (big) colloidal spheres using the Derjaguin approximation 2.7 Measurements of depletion interactions 2.7.1 Atomic force microscope 2.7.2 Total internal eflection microscopy 2.7.3 Optical tweezers 3 Phase transitions of hard spheres plus depletants basics 3.1 Introduction -colloid/atom analogy 3.2 The hard sphere fluid-crystal transition 3.3 Free volume theory Appendix 3.1. Statistical Mechanical derivation of the Free Volume Theory 4 Stability of colloid-polymer mixtures 4.1 Experimental state diagrams of colloid-polymer mixtures 4.2 Phase behaviour of colloid + ideal polymer mixtures 4.3 Phase behaviour of sphere plus interacting polymer mixtures GFVT 4.3.1 Depletion thickness and osmotic pressure 4.3.2 Protein Limit 4.4 Non-equilibrium phenomena 4.4.1 Unmixing kinetics 4.4.2 Aggregation and gelation 4.4.3 Depletion effects on colloidal glasses 5 Phase transitions of hard spheres plus colloids 5.1 Free volume theory for big plus small hard spheres 5.2 Phase behavior of mixed spheres 5.2.1 Phase separation in binary mixtures differing only in diameter 5.2.2 Mixtures of latex particles and micelles 5.2.3 Oil-in-water emulsion particles and micelles of the stabilizing surfactant 5.3 free volume theory for sphere-rod mixtures 5.4 Phase behaviour of sphere-rod mixtures 6 Suspensions of rod-like colloids plus polymers 6.1 Onsager theory of the isotropic-nematic transition 6.2 Scaled particle theory of the isotropic-nematic transition 6.3 Isotropic-nematic phase behaviour of rods plus phs 6.4 I-N phase behaviour of rods plus polymers 6.4.1 Rod-like colloids plus ideal polymers 6.4.2 Rod-like colloids plus interacting polymers 6.5 Experiments on rod/polymer mixtures 6.5.1 Stiff virusparticles + polymer 6.5.2 Cellulose nanocrystals + polymer 6.5.3 Sterically stabilized colloidal boehmite rods + polymer 6.6 Rod/polymer mixtures: full phase diagrams. 6.7 Concluding remarks. List of symbols Index

Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

Abstract: The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compel additional exploration. We therefore undertook whole-genome sequencing of the acidogenic A. niger wild-type strain (ATCC 1015) and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence, and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was used to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 Mb of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis supported up-regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases, and protein transporters in the protein producing CBS 513.88 strain. Our results and data sets from this integrative systems biology analysis resulted in a snapshot of fungal evolution and will support further optimization of cell factories based on filamentous fungi.

Quantitative metabolomics based on gas chromatography mass spectrometry: status and perspectives

Abstract: Metabolomics involves the unbiased quantitative and qualitative analysis of the complete set of metabolites present in cells, body fluids and tissues (the metabolome). By analyzing differences between metabolomes using biostatistics (multivariate data analysis; pattern recognition), metabolites relevant to a specific phenotypic characteristic can be identified. However, the reliability of the analytical data is a prerequisite for correct biological interpretation in metabolomics analysis. In this review the challenges in quantitative metabolomics analysis with regards to analytical as well as data preprocessing steps are discussed. Recommendations are given on how to optimize and validate comprehensive silylation-based methods from sample extraction and derivatization up to data preprocessing and how to perform quality control during metabolomics studies. The current state of method validation and data preprocessing methods used in published literature are discussed and a perspective on the future research necessary to obtain accurate quantitative data from comprehensive GC-MS data is provided.

The formation of disc galaxies in a ΛCDM universe

Abstract: We study the formation of disc galaxies in a fully cosmological framework using adaptive mesh refinement simulations. We perform an extensive parameter study of the main subgrid processes that control how gas is converted into stars and the coupled effect of supernovae feedback. We argue that previous attempts to form disc galaxies have been unsuccessful because of the universal adoption of strong feedback combined with high star formation efficiencies. Unless extreme amounts of energy are injected into the interstellar medium during supernovae events, these star formation parameters result in bulge dominated S0/Sa galaxies as star formation is too efficient at z~3. We show that a low efficiency of star-formation more closely models the subparsec physical processes, especially at high redshift. We highlight the successful formation of extended disc galaxies with scale lengths r_d=4-5 kpc, flat rotation curves and bulge to disc ratios of B/D~1/4. Not only do we resolve the formation of a Milky Way-like spiral galaxy, we also observe the secular evolution of the disc as it forms a pseudo-bulge. The disc properties agree well with observations and are compatible with the photometric and baryonic Tully-Fisher relations, the Kennicutt-Schmidt relation and the observed angular momentum content of spiral galaxies. We conclude that underlying small-scale star formation physics plays a larger role than previously considered in simulations of galaxy formation.

A mitochondrial enzyme degrades carotenoids and protects against oxidative stress.

Abstract: Carotenoids are the precursors for vitamin A and are proposed to prevent oxidative damage to cells. Mammalian genomes encode a family of structurally related nonheme iron oxygenases that modify double bonds of these compounds by oxidative cleavage and cis-to-trans isomerization. The roles of the family members BCMO1 and RPE65 for vitamin A production and vision have been well established. Surprisingly, we found that the third family member, β,β-carotene-9',10'-oxygenase (BCDO2), is a mitochondrial carotenoid-oxygenase with broad substrate specificity. In BCDO2-deficient mice, carotenoid homeostasis was abrogated, and carotenoids accumulated in several tissues. In hepatic mitochondria, accumulated carotenoids induced key markers of mitochondrial dysfunction, such as manganese superoxide dismutase (9-fold), and reduced rates of ADP-dependent respiration by 30%. This impairment was associated with an 8- to 9-fold induction of phosphor-MAP kinase and phosphor-AKT, markers of cell signaling pathways related to oxidative stress and disease. Administration of carotenoids to human HepG2 cells depolarized mitochondrial membranes and resulted in the production of reactive oxygen species. Thus, our studies in BCDO2-deficient mice and human cell cultures indicate that carotenoids can impair respiration and induce oxidative stress. Mammalian cells thus express a mitochondrial carotenoid-oxygenase that degrades carotenoids to protect these vital organelles.

Planck early results. VII. The Early Release Compact Source Catalogue

Abstract: A brief description of the methodology of construction, contents and usage of the Planck Early Release Compact Source Catalogue (ERCSC), including the Early Cold Cores (ECC) and the Early Sunyaev-Zeldovich (ESZ) cluster catalogue is provided. The catalogue is based on data that consist of mapping the entire sky once and 60% of the sky a second time by Planck, thereby comprising the first high sensitivity radio/submillimetre observations of the entire sky. Four source detection algorithms were run as part of the ERCSC pipeline. A Monte-Carlo algorithm based on the injection and extraction of artificial sources into the Planck maps was implemented to select reliable sources among all extracted candidates such that the cumulative reliability of the catalogue is ≥90%. There is no requirement on completeness for the ERCSC. As a result of the Monte-Carlo assessment of reliability of sources from the different techniques, an implementation of the PowellSnakes source extraction technique was used at the five frequencies between 30 and 143GHz while the SExtractor technique was used between 217 and 857GHz. The 10σ photometric flux density limit of the catalogue at |b| > 30° is 0.49, 1.0, 0.67, 0.5, 0.33, 0.28, 0.25, 0.47 and 0.82 Jy at each of the nine frequencies between 30 and 857GHz. Sources which are up to a factor of ~2 fainter than this limit, and which are present in “clean” regions of the Galaxy where the sky background due to emission from the interstellar medium is low, are included in the ERCSC if they meet the high reliability criterion. The Planck ERCSC sources have known associations to stars with dust shells, stellar cores, radio galaxies, blazars, infrared luminous galaxies and Galactic interstellar medium features. A significant fraction of unclassified sources are also present in the catalogs. In addition, two early release catalogs that contain 915 cold molecular cloud core candidates and 189 SZ cluster candidates that have been generated using multifrequency algorithms are presented. The entire source list, with more than 15000 unique sources, is ripe for follow-up characterisation with Herschel, ATCA, VLA, SOFIA, ALMA and other ground-based observing facilities.

Stellar black holes at the dawn of the universe

Abstract: Fil: Mirabel Miquele, Igor Felix. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Astronomia y Fisica del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomia y Fisica del Espacio; Argentina

Acute resveratrol supplementation improves flow-mediated dilatation in overweight/obese individuals with mildly elevated blood pressure.

Abstract: Background and Aims: Flow-mediated dilatation of the brachial artery (FMD) is a biomarker of endothelial function and cardiovascular health. Impaired FMD is associated with several cardiovascular risk factors including hypertension and obesity. Various food ingredients such as polyphenols have been shown to improve FMD. We investigated whether consuming re- sveratrol, a polyphenol found in red wine, can enhance FMD acutely and whether there is a dose-response relationship for this effect. Methods and Results: 19 overweight/obese (BMI 25e35 kg m � 2 ) men or post-menopausal women with untreated borderline hypertension (systolic BP: 130e160 mmHg or diastolic BP: 85e100 mmHg) consumed three doses of resveratrol (resVida� 30, 90 and 270 mg) and a placebo at weekly intervals in a double-blind, randomized crossover comparison. One hour after consumption of the supplement, plasma resveratrol and FMD were measured. Data were analyzed by linear regression versus log10 dose of resveratrol. 14 men and 5 women (age 55 � 2 years, BMI 28.7 � 0.5 kg m � 2 ,B P 141� 2/89 � 1 mmHg) completed this study. There was a significant dose effect of resveratrol on plasma resveratrol concentration (P < 0.001) and on FMD (P < 0.01), which increased from 4.1 � 0.8% (placebo) to 7.7 � 1.5% after 270 mg resveratrol. FMD was also linearly related to log10 plasma resveratrol concentration (P < 0.01).

Planck early results. XXV. Thermal dust in nearby molecular clouds

Abstract: Planck allows unbiased mapping of Galactic sub-millimetre and millimetre emission from the most diffuse regions to the densest parts of molecular clouds. We present an early analysis of the Taurus molecular complex, on line-of-sight-averaged data and without component separation. The emission spectrum measured by Planck and IRAS can be fitted pixel by pixel using a single modified blackbody. Some systematic residuals are detected at 353 GHz and 143 GHz, with amplitudes around −7% and +13%, respectively, indicating that the measured spectra are likely more complex than a simple modified blackbody. Significant positive residuals are also detected in the molecular regions and in the 217 GHz and 100 GHz bands, mainly caused by the contribution of the J = 2 → 1a ndJ = 1 → 0 12 CO and 13 CO emission lines. We derive maps of the dust temperature T , the dust spectral emissivity index β, and the dust optical depth at 250 μm τ250. The temperature map illustrates the cooling of the dust particles in thermal equilibrium with the incident radiation field, from 16−17 K in the diffuse regions to 13−14 K in the dense parts. The distribution of spectral indices is centred at 1.78, with a standard deviation of 0.08 and a systematic error of 0.07. We detect a significant T − β anti-correlation. The dust optical depth map reveals the spatial distribution of the column density of the molecular complex from the densest molecular regions to the faint diffuse regions. We use near-infrared extinction and H i data at 21-cm to perform a quantitative analysis of the spatial variations of the measured dust optical depth at 250 μm per hydrogen atom τ250/NH. We report an increase of τ250/NH by a factor of about 2 between the atomic phase and the molecular phase, which has a strong impact on the equilibrium temperature of the dust particles.

Planck early results. XVIII. The power spectrum of cosmic infrared background anisotropies

Abstract: Using Planck maps of six regions of low Galactic dust emission with a total area of about 140 deg 2 , we determine the angular power spectra of cosmic infrared background (CIB) anisotropies from multipole � = 200 to � = 2000 at 217, 353, 545 and 857 GHz. We use 21-cm observations of Hi as a tracer of thermal dust emission to reduce the already low level of Galactic dust emission and use the 143 GHz Planck maps in these fields to clean out cosmic microwave background anisotropies. Both of these cleaning processes are necessary to avoid significant contamination of the CIB signal. We measure correlated CIB structure across frequencies. As expected, the correlation decreases with increasing frequency separation, because the contribution of high-redshift galaxies to CIB anisotropies increases with wavelengths. We find no significant difference between the frequency spectrum of the CIB anisotropies and the CIB mean, with ΔI/I = 15% from 217 to 857 GHz. In terms of clustering properties, the Planck data alone rule out the linear scale- and redshift-independent bias model. Non-linear corrections are significant. Consequently, we develop an alternative model that couples a dusty galaxy, parametric evolution model with a simple halo-model approach. It provides an excellent fit to the measured anisotropy angular power spectra and suggests that a different halo occupation distribution is required at each frequency, which is consistent with our expectation that each frequency is dominated by contributions from different redshifts. In our best-fit model, half of the anisotropy power at � = 2000 comes from redshifts z 2a t 353 and 217 GHz, respectively.

Planck early results - XXIV. Dust in the diffuse interstellar medium and the galactic halo

Abstract: This paper presents the first results from a comparison of Planck dust maps at 353, 545 and 857GHz, along with IRAS data at 3000 (100 μm) and 5000GHz (60 μm), with Green Bank Telescope 21-cm observations of Hi in 14 fields covering more than 800deg(2) at high Galactic latitude. The main goal of this study is to estimate the far-infrared to sub-millimeter (submm) emissivity of dust in the diffuse local interstellar medium (ISM) and in the intermediate-velocity (IVC) and high-velocity clouds (HVC) of the Galactic halo. Galactic dust emission for fields with average Hi column density lower than 2 × 10(20) cm(-20) is well correlated with 21-cm emission because in such diffuse areas the hydrogen is predominantly in the neutral atomic phase. The residual emission in these fields, once the Hi-correlated emission is removed, is consistent with the expected statistical properties of the cosmic infrared background fluctuations. The brighter fields in our sample, with an average Hi column density greater than 2 × 10(20) cm(-2), show significant excess dust emission compared to the Hi column density. Regions of excess lie in organized structures that suggest the presence of hydrogen in molecular form, though they are not always correlated with CO emission. In the higher Hi column density fields the excess emission at 857 GHz is about 40% of that coming from the Hi, but over all the high latitude fields surveyed the molecular mass faction is about 10%. Dust emission from IVCs is detected with high significance by this correlation analysis. Its spectral properties are consistent with, compared to the local ISM values, significantly hotter dust (T ~ 20 K), lower submm dust opacity normalized per H-atom, and a relative abundance of very small grains to large grains about four times higher. These results are compatible with expectations for clouds that are part of the Galactic fountain in which there is dust shattering and fragmentation. Correlated dust emission in HVCs is not detected; the average of the 99.9% confidence upper limits to the emissivity is 0.15 times the local ISM value at 857 and 3000GHz, in accordance with gas phase evidence for lower metallicity and depletion in these clouds. Unexpected anti-correlated variations of the dust temperature and emission cross-section per H atom are identified in the local ISM and IVCs, a trend that continues into molecular environments. This suggests that dust growth through aggregation, seen in molecular clouds, is active much earlier in the cloud condensation and star formation processes.

Biotechnological production of astaxanthin with Phaffia rhodozyma / Xanthophyllomyces dendrorhous

Abstract: The oxygenated β-carotene derivative astaxanthin exhibits outstanding colouring, antioxidative and health-promoting properties and is mainly found in the marine environment. To satisfy the growing demand for this ketocarotenoid in the feed, food and cosmetics industries, there are strong efforts to develop economically viable bioprocesses alternative to the current chemical synthesis. However, up to now, natural astaxanthin from Haematococcus pluvialis, Phaffia rhodozyma or Paracoccus carotinifaciens has not been cost competitive with chemically synthesized astaxanthin, thus only serving niche applications. This review illuminates recent advances made in elucidating astaxanthin biosynthesis in P. rhodozyma. It intensely focuses on strategies to increase astaxanthin titers in the heterobasidiomycetous yeast by genetic engineering of the astaxanthin pathway, random mutagenesis and optimization of fermentation processes. This review emphasizes the potential of P. rhodozyma for the biotechnological production of astaxanthin in comparison to other natural sources such as the microalga H. pluvialis, other fungi and transgenic plants and to chemical synthesis.

CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey

Abstract: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8--1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the mid-ultraviolet to the near-infrared, and will find and measure Type Ia supernovae at z>1.5 to test their accuracy as standardizable candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10^9 M_\odot to z \approx 2, reaching the knee of the ultraviolet luminosity function (UVLF) of galaxies to z \approx 8. The survey covers approximately 800 arcmin^2 and is divided into two parts. The CANDELS/Deep survey (5\sigma\ point-source limit H=27.7 mag) covers \sim 125 arcmin^2 within GOODS-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (EGS, COSMOS, and UDS) and covers the full area to a 5\sigma\ point-source limit of H \gtrsim 27.0 mag. Together with the Hubble Ultra Deep Fields, the strategy creates a three-tiered "wedding cake" approach that has proven efficient for extragalactic surveys. Data from the survey are nonproprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design. The Hubble data processing and products are described in a companion paper.

Planck early results - XI. Calibration of the local galaxy cluster Sunyaev-Zeldovich scaling relations

Abstract: We present precise Sunyaev-Zeldovich (SZ) effect measurements in the direction of 62 nearby galaxy clusters (z < 0.5) detected at high signal-tonoise in the first Planck all-sky data set. The sample spans approximately a decade in total mass, 2 × 10 14 M� < M500 < 2 × 10 15 M� ,w hereM500 is the mass corresponding to a total density contrast of 500. Combining these high quality Planck measurements with deep XMM-Newton X-ray data, we investigate the relations between D 2 Y500, the integrated Compton parameter due to the SZ effect, and the X-ray-derived gas mass Mg,500, temperature TX, luminosity LX,500, SZ signal analogue YX,500 = Mg,500 ×TX, and total mass M500. After correction for the effect of selection bias on the scaling relations, we find results that are in excellent agreement with both X-ray predictions and recently-published ground-based data derived from smaller samples. The present data yield an exceptionally robust, high-quality local reference, and illustrate Planck’s unique capabilities for all-sky statistical studies of galaxy clusters.

Discovery of the nearby long, soft GRB 100316D with an associated supernova

Abstract: We report the Swift discovery of the nearby long, soft gamma-ray burst GRB 100316D, and the subsequent unveiling of its low-redshift host galaxy and associated supernova. We derive the redshift of the event to be z = 0.0591 +/- 0.0001 and provide accurate astrometry for the gamma-ray burst (GRB) supernova (SN). We study the extremely unusual prompt emission with time-resolved gamma-ray to X-ray spectroscopy and find that the spectrum is best modelled with a thermal component in addition to a synchrotron emission component with a low peak energy. The X-ray light curve has a remarkably shallow decay out to at least 800 s. The host is a bright, blue galaxy with a highly disturbed morphology and we use Gemini-South, Very Large Telescope and Hubble Space Telescope observations to measure some of the basic host galaxy properties. We compare and contrast the X-ray emission and host galaxy of GRB 100316D to a subsample of GRB-SNe. GRB 100316D is unlike the majority of GRB-SNe in its X-ray evolution, but resembles rather GRB 060218, and we find that these two events have remarkably similar high energy prompt emission properties. Comparison of the host galaxies of GRB-SNe demonstrates, however, that there is a great diversity in the environments in which GRB-SNe can be found. GRB 100316D is an important addition to the currently sparse sample of spectroscopically confirmed GRB-SNe, from which a better understanding of long GRB progenitors and the GRB-SN connection can be gleaned.