12 research outputs found

    Hi-fidelity multi-scale local processing for visually optimized far-infrared Herschel images

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    In the context of the "Hi-Gal" multi-band full-plane mapping program for the Galactic Plane, as imaged by the Herschel far-infrared satellite, we have developed a semi-automatic tool which produces high definition, high quality color maps optimized for visual perception of extended features, like bubbles and filaments, against the high background variations. We project the map tiles of three selected bands onto a 3-channel panorama, which spans the central 130 degrees of galactic longitude times 2.8 degrees of galactic latitude, at the pixel scale of 3.2", in cartesian galactic coordinates. Then we process this image piecewise, applying a custom multi-scale local stretching algorithm, enforced by a local multi-scale color balance. Finally, we apply an edge-preserving contrast enhancement to perform an artifact-free details sharpening. Thanks to this tool, we have thus produced a stunning giga-pixel color image of the far-infrared Galactic Plane that we made publicly available with the recent release of the Hi-Gal mosaics and compact source catalog. <P /

    Performance analysis of the GR712RC dual-core LEON3FT SPARC V8 processor in an asymmetric multi-processing environment

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    In this paper we present the results of a series of performance tests carried out on a prototype board mounting the Cobham Gaisler GR712RC Dual Core LEON3FT processor. The aim was the characterization of the performances of the dual core processor when used for executing a highly demanding lossless compression task, acting on data segments continuously copied from the static memory to the processor RAM. The selection of the compression activity to evaluate the performances was driven by the possibility of a comparison with previously executed tests on the Cobham/Aeroflex Gaisler UT699 LEON3FT SPARC™ V8. The results of the test activity have shown a factor 1.6 of improvement with respect to the previous tests, which can easily be improved by adopting a faster onboard board clock, and provided indications on the best size of the data chunks to be used in the compression activity

    A study of the cold cores population in the Serpens star-forming region

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    As part of the Herschel Gould Belt survey, the Serpens star-forming region was observed with the Herschel PACS and SPIRE instruments. Data analysis is ongoing and a first version of the source catalog is ready; here we show some preliminary results

    The population of merging compact binaries inferred using gravitational waves through GWTC-3

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    We report on the population properties of 76 compact binary mergers detected with gravitational waves below a false alarm rate of 1 per year through GWTC-3. The catalog contains three classes of binary mergers: BBH, BNS, and NSBH mergers. We infer the BNS merger rate to be between 10 Gpc3yr1\rm{Gpc^{-3} yr^{-1}} and 1700 Gpc3yr1\rm{Gpc^{-3} yr^{-1}} and the NSBH merger rate to be between 7.8 Gpc3yr1\rm{Gpc^{-3}\, yr^{-1}} and 140 Gpc3yr1\rm{Gpc^{-3} yr^{-1}} , assuming a constant rate density versus comoving volume and taking the union of 90% credible intervals for methods used in this work. Accounting for the BBH merger rate to evolve with redshift, we find the BBH merger rate to be between 17.9 Gpc3yr1\rm{Gpc^{-3}\, yr^{-1}} and 44 Gpc3yr1\rm{Gpc^{-3}\, yr^{-1}} at a fiducial redshift (z=0.2). We obtain a broad neutron star mass distribution extending from 1.20.2+0.1M1.2^{+0.1}_{-0.2} M_\odot to 2.00.3+0.3M2.0^{+0.3}_{-0.3} M_\odot. We can confidently identify a rapid decrease in merger rate versus component mass between neutron star-like masses and black-hole-like masses, but there is no evidence that the merger rate increases again before 10 MM_\odot. We also find the BBH mass distribution has localized over- and under-densities relative to a power law distribution. While we continue to find the mass distribution of a binary's more massive component strongly decreases as a function of primary mass, we observe no evidence of a strongly suppressed merger rate above 60M\sim 60 M_\odot. The rate of BBH mergers is observed to increase with redshift at a rate proportional to (1+z)κ(1+z)^{\kappa} with κ=2.91.8+1.7\kappa = 2.9^{+1.7}_{-1.8} for z1z\lesssim 1. Observed black hole spins are small, with half of spin magnitudes below χi0.25\chi_i \simeq 0.25. We observe evidence of negative aligned spins in the population, and an increase in spin magnitude for systems with more unequal mass ratio

    A traffic analyzer for multiple SpaceWire links

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    Modern space missions are becoming increasingly complex: the interconnection of the units in a satellite is now a network of terminals linked together through routers, where devices with different level of automation and intelligence share the same data-network. The traceability of the network transactions is performed mostly at terminal level through log analysis and hence it is difficult to verify in real time the reliability of the interconnections and the interchange protocols. To improve and ease the traffic analysis in a SpaceWire network we implemented a low-level link analyzer, with the specific goal to simplify the integration and test phases in the development of space instrumentation. The traffic analyzer collects signals coming from pod probes connected in-series on the interested links between two SpaceWire terminals. With respect to the standard traffic analyzers, the design of this new tool includes the possibility to internally reshape the LVDS signal. This improvement increases the robustness of the analyzer towards environmental noise effects and guarantees a deterministic delay on all analyzed signals. The analyzer core is implemented on a Xilinx FPGA, programmed to decode the bidirectional LVDS signals at Link and Network level. Successively, the core packetizes protocol characters in homogeneous sets of time ordered events. The analyzer provides time-tagging functionality for each characters set, with a precision down to the FPGA Clock, i.e. about 20nsec in the adopted HW environment. The use of a common time reference for each character stream allows synchronous performance measurements. The collected information is then routed to an external computer for quick analysis: this is done via high-speed USB2 connection. With this analyzer it is possible to verify the link performances in terms of induced delays in the transmitted signals. A case study focused on the analysis of the Time-Code synchronization in presence of a SpaceWire Router is shown in this paper as well

    The Hi-GAL compact source catalogue - I. The physical properties of the clumps in the inner Galaxy (-71.0° < ℓ < 67.0°)

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    Hi-GAL (Herschel InfraRed Galactic Plane Survey) is a large-scale survey of the Galactic plane, performed with Herschel in five infrared continuum bands between 70 and 500 μm. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogues presented in Molinari et al., covering the portion of Galactic plane -71.0° < ℓ < 67.0°. The band-merged catalogue contains 100 922 sources with a regular SED, 24 584 of which show a 70-μm counterpart and are thus considered protostellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterize different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in protostellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to protostellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between 'on-arm' and 'interarm' positions

    The population of merging compact binaries inferred using gravitational waves through GWTC-3

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    v2: minor edits, most to Table 1 and caption; v3: rerun with public data; Data release: https://zenodo.org/record/5655785; v4: update Fig 14We report on the population properties of 76 compact binary mergers detected with gravitational waves below a false alarm rate of 1 per year through GWTC-3. The catalog contains three classes of binary mergers: BBH, BNS, and NSBH mergers. We infer the BNS merger rate to be between 10 Gpc3yr1\rm{Gpc^{-3} yr^{-1}} and 1700 Gpc3yr1\rm{Gpc^{-3} yr^{-1}} and the NSBH merger rate to be between 7.8 Gpc3yr1\rm{Gpc^{-3}\, yr^{-1}} and 140 Gpc3yr1\rm{Gpc^{-3} yr^{-1}} , assuming a constant rate density versus comoving volume and taking the union of 90% credible intervals for methods used in this work. Accounting for the BBH merger rate to evolve with redshift, we find the BBH merger rate to be between 17.9 Gpc3yr1\rm{Gpc^{-3}\, yr^{-1}} and 44 Gpc3yr1\rm{Gpc^{-3}\, yr^{-1}} at a fiducial redshift (z=0.2). We obtain a broad neutron star mass distribution extending from 1.20.2+0.1M1.2^{+0.1}_{-0.2} M_\odot to 2.00.3+0.3M2.0^{+0.3}_{-0.3} M_\odot. We can confidently identify a rapid decrease in merger rate versus component mass between neutron star-like masses and black-hole-like masses, but there is no evidence that the merger rate increases again before 10 MM_\odot. We also find the BBH mass distribution has localized over- and under-densities relative to a power law distribution. While we continue to find the mass distribution of a binary's more massive component strongly decreases as a function of primary mass, we observe no evidence of a strongly suppressed merger rate above 60M\sim 60 M_\odot. The rate of BBH mergers is observed to increase with redshift at a rate proportional to (1+z)κ(1+z)^{\kappa} with κ=2.91.8+1.7\kappa = 2.9^{+1.7}_{-1.8} for z1z\lesssim 1. Observed black hole spins are small, with half of spin magnitudes below χi0.25\chi_i \simeq 0.25. We observe evidence of negative aligned spins in the population, and an increase in spin magnitude for systems with more unequal mass ratio
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