The Swift X-ray Telescope Cluster Survey III: Cluster Catalog from 2005-2012 Archival Data

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 to 2012, 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 degree to avoid high HI 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 degree^2. We identify extended source candidates in the soft-band (0.5-2keV) 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 7E-15 erg/cm^2/s 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 SZ catalogs of clusters. We find that 137 sources have been previously identified as clusters, 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.Comment: 41 pages, 16 figures, 3 tables, published on ApJS in Jan 201

Drug repositioning : a machine-learning approach through data integration

Existing computational methods for drug repositioning either rely only on the gene expression response of cell lines after treatment, or on drug-to-disease relationships, merging several information levels. However, the noisy nature of the gene expression and the scarcity of genomic data for many diseases are important limitations to such approaches. Here we focused on a drug-centered approach by predicting the therapeutic class of FDA-approved compounds, not considering data concerning the diseases. We propose a novel computational approach to predict drug repositioning based on state-of-the-art machine-learning algorithms. We have integrated multiple layers of information: i) on the distances of the drugs based on how similar are their chemical structures, ii) on how close are their targets within the protein-protein interaction network, and iii) on how correlated are the gene expression patterns after treatment. Our classifier reaches high accuracy levels (78%), allowing us to re-interpret the top misclassifications as re-classifications, after rigorous statistical evaluation. Efficient drug repurposing has the potential to significantly impact the whole field of drug development. The results presented here can significantly accelerate the translation into the clinics of known compounds for novel therapeutic uses

Techno-Economic Assessment of the Supercritical Carbon Dioxide Enhanced Geothermal Systems

Enhanced geothermal systems distinguish themselves among other technologies that utilize renewable energy sources by their possibility of the partial sequestration of carbon dioxide (CO2). Thus, CO2 in its supercritical form in such units may be considered as better working fluid for heat transfer than conventionally used water. The main goal of the study was to perform the techno-economic analysis of different configurations of supercritical carbon dioxide-enhanced geothermal systems (sCO2-EGSs). The energy performance as well as economic evaluation including heat and power generation, capital and operational expenditures, and levelized cost of electricity and heat were investigated based on the results of mathematical modeling and process simulations. The results indicated that sCO2 mass flow rates and injection temperature have a significant impact on energetic results and also cost estimation. In relation to financial assessment, the highest levelized cost of electricity was obtained for the indirect sCO2 cycle (219.5 EUR/MWh) mainly due to the lower electricity production (in comparison with systems using Organic Rankine Cycle) and high investment costs. Both energy and economic assessments in this study provide a systematic approach to compare the sCO2-EGS variants. Keywords: enhanced geothermal systems; CO2-EGS; supercritical carbon dioxide cycles; Organic Rankine Cycle; combined heat and power; geothermal energyTechno-Economic Assessment of the Supercritical Carbon Dioxide Enhanced Geothermal SystemspublishedVersio

Test plan of the BEaTriX paraboloidal mirror at PANTER

Scope of this technical note is the definition of a test plan for the X-ray characterization campaign of the BEaTriX paraboloidal mirror at PANTER. The collimating mirror is a core component of the 4.51 keV beamline of the BEaTriX expanded X-ray beam facility; indeed, the optical quality of the mirror will directly affect the collimation and the uniformity of the final beam that will be used to characterize the focusing performance of SPO MM for ATHENA. The mirror is made of HOQ 310 fused quartz, procured from Zeiss in a preliminary grinding and lapping state, and subsequently finished by a sequence of polishing at the Zeeko robotic machine installed at INAF-OAB. Improvement of the mirror figure has been achieved across several runs of IBF process, using the dedicated facility at INAF-OAB. At each polishing/figuring step, the mirror profile and surface roughness have been characterized using suitable metrology tools at MediaLario

Interaction of Skeletal and Left Ventricular Mass in Older Adults with Low Muscle Performance

BACKGROUND: It was recently hypothesized the existence of “cardiac-skeletal muscle axis.” However, the relationship between skeletal muscle mass (SMM) and left ventricular mass (LVM) has never been investigated in the specific group of older individuals with low skeletal mass and physical performance. We tested this hypothesis in the SPRINT-T (Sarcopenia and Physical Frailty IN older people: multicomponenT Treatment strategies Trial) population using LVM as independent variable and SMM as dependent variable. METHODS: SMM was assessed by dual-energy X-ray absorptiometry scan and expressed as appendicular lean mass (ALM), and LVM was estimated through echocardiography. Low ALM was defined according to Foundation for the National Institutes of Health Sarcopenia Project criteria, and Short Physical Performance Battery (SPPB) was used to assess physical performance.RESULTS: The population consisted of 100 persons (33 men and 67 women), aged 70 years or older (mean age = 79 5 years) with low ALM and SPPB ranged between 3 and 9, suggestive of physical frailty. Charlson Comorbidity Index median score was 0. Mean value of LVM was 193 67 g, indexed LVM/body surface area (LVM/BSA) was 112 33 g/m2, and cardiac output (CO) was 65 19 L/min. ALM was strongly and positively correlated with LVM (r = 0.54602; P < .0001), LVM/BSA (r = 0.30761; P < .002), CO (r = 0.49621; P < .0001), body mass index (BMI) (r = 0.52461; P < .0001), sex (r = 0.77; P < .001), fat mass (r = 0.38977; P < .0001), and hemoglobin (Hb) (r = 0.26001; P < .01). In the multivariate analysis, LVM (β = .019 .005; P < .0001), CO (β = .038 .016; P = .019), BMI (β = .286 .051; P < .0001), and Hb (β = .544 .175; P = .0025) remained associated to ALM. CONCLUSIONS: In a sample of older persons with low muscle mass and physical performance, LVM was positively and significantly correlated with ALM, independently from blood pressure, physical activity, and other potential confounders. Future studies are needed to address the effect of interventions targeting LVM and SMM

Direct hot slumping of thin glass foils for future generation x-ray telescopes: current state of the art and future outlooks

To significantly improve the performances of the current X-ray observatories, the next generation of X-ray telescopes has to be characterized by a large effective area (Aeff { 2 m2 at 1 keV) and angular resolution better than 5 arcsec. The large dimension implied by these requirements forces the use of a modular approach, splitting the optics into segments. Moreover, lightweight materials, such as glass, have to be selected for the segmented optics in order to maintain a manageable weight for the optics. Since 2009 we are developing a direct hot slumping technique assisted by pressure, in which the glass optical surface is in contact with the mould and a pressure is applied in order to force the glass to copy the mould shape. A cold slumping step is used then to integrate the mirror segments into the final Wolter-I configuration. We present the state of the art of our hot slumping technology, comparing the results obtained with different glass types and mould materials. We also provide an overview of the possibilities of this technology also in view of future developments

Design and manufacturing of a compact two-mirror system for multispectral imaging applications

Spectral imaging systems drive the development of remote sensing applications. The possibility to combine integrated multispectral sensors to compact, broadband and wide field optical systems is highly advantageous in terms of reliability, portability, and cost reduction. On the other hand, such optical systems often rely on the feasibility of demanding optical components, as of strongly aspheric optics. The activity of manufacturing and metrological testing of such optics is crucial for the achievement of the whole project. In this paper, we present the design of a compact two-mirror system and the manufacturing of the strongly aspheric primary mirror

Simbol-X: a formation flight mission with an unprecedented imaging capability in the 0.5-80 keV energy band

The discovery of X-ray emission from cosmic sources in the 1960s has opened a new powerful observing window on the Universe. In fact, the exploration of the X-ray sky during the 70s-90s has established X-ray astronomy as a fundamental field of astrophysics. Today, the emission from astrophysical sources is by large best known at energies below 10 keV. The main reason for this situation is purely technical since grazing incidence reflection has so far been limited to the soft X-ray band. Above 10 keV all the observations have been obtained with collimated detectors or coded mask instruments. To make a leap step forward in Xray astronomy above 10 keV it is necessary to extend the principle of focusing X ray optics to higher energies, up to 80 keV and beyond. To this end, ASI and CNES are presently studying the implementation of a X-ray mission called Simbol-X. Taking advantage of emerging technology in mirror manufacturing and spacecraft formation flying, Simbol-X will push grazing incidence imaging up to 80 keV and beyond, providing a strong improvement both in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. This technological breakthrough will open a new highenergy window in astrophysics and cosmology. Here we will address the problematic of the development for such a distributed and deformable instrument. We will focus on the main performances of the telescope, like angular resolution, sensitivity and source localization. We will also describe the specificity of the calibration aspects of the payload distributed over two satellites and therefore in a not "frozen" configuration

Design and advancement status of the Beam Expander Testing X-ray facility (BEaTriX)

The BEaTriX (Beam Expander Testing X-ray facility) project is an X-ray apparatus under construction at INAF/OAB to generate a broad (200́60 mm2), uniform and low-divergent X-ray beam within a small lab (6́15 m2). BEaTriX will consist of an X-ray source in the focus a grazing incidence paraboloidal mirror to obtain a parallel beam, followed by a crystal monochromation system and by an asymmetrically-cut diffracting crystal to perform the beam expansion to the desired size. Once completed, BEaTriX will be used to directly perform the quality control of focusing modules of large X-ray optics such as those for the ATHENA X-ray observatory, based on either Silicon Pore Optics (baseline) or Slumped Glass Optics (alternative), and will thereby enable a direct quality control of angular resolution and effective area on a number of mirror modules in a short time, in full X-ray illumination and without being affected by the finite distance of the X-ray source. However, since the individual mirror modules for ATHENA will have an optical quality of 3-4 arcsec HEW or better, BEaTriX is required to produce a broad beam with divergence below 1-2 arcsec, and sufficient flux to quickly characterize the PSF of the module without being significantly affected by statistical uncertainties. Therefore, the optical components of BEaTriX have to be selected and/or manufactured with excellent optical properties in order to guarantee the final performance of the system. In this paper we report the final design of the facility and a detailed performance simulation

A vertical facility based on raster scan configuration for the x-ray scientific calibrations of the ATHENA optics

The ATHENA X-ray observatory is a large-class ESA approved mission, with launch scheduled in 2028. The technology of Silicon Pore Optics (SPO) was selected since 2004 as the baseline for making the X-ray Mirror Assembly. Up to 700 mirror modules to obtain a nested Wolter like optics. The maximum diameter of the shells will be 2.5 m while the focal length is 12 m. The requirements for on-axis angular resolution and effective area at 1 keV are 5 arcsec HEW and 1.4 m2, while the field of view will be 40 arcmin in diameter (50 % vignetting). While in this moment there an on-going effort aiming at demonstrating the feasibility of a so large optics with so stringent scientific requirements, an important aspect to be considered regards the scientific calibrations of the X-ray optics. In this respect, the Point Spread Function and effective area have to be correctly measured and calibrated on-ground at different energies across the entire field of view, with a low vignetting. The approach considered so far foresees the use of a long (several hundreds of meters) facility to allow a full illumination with low divergence of the entire optics module (or at least of large sections of it). The implementation of similar configurations in a completely new facility to be realized in Europe (friendly called "super Panter") or the retrofitting existing facilities like the XRCF at NASA/MSFC are being considered. In both cases the costs and the programmatic risks related to the implementation of these huge facilities, with their special jigs for the alignment of the ATHENA optics, represent important aspects to be considered. Moreover, the horizontal position of the optics to be used in full illumination facilities would determine gravitational deformations, not easy to be removed with actuators or by modeling. In this talk we will discuss a completely different concept, based on the mount of the optics in vertical position and the use of a raster scan of the ATHENA optics with a small (a few cm2 wide) highly collimated (1 arcsec or so) white beam X-ray. This system will allow us to operate a much compact system. The use of a vertical configuration will imply smaller gravitational deformations, that can be controlled with actuators able to compensate them. A proper camera system with a sufficient energy resolution will be able to grant a correct measurement of both PSF and effective area of the Mirror Assembly within the calibration requirements and in a reasonable integration time. Moreover, it may allow us also to perform end-to-end tests using the two flight focal plane instruments of ATHENA. The cost and risks for the implementation would be much lower than for the full illumination systems. The conceptual configuration and preliminary expected performance of the facility will be discussed