The INTEGRAL/SPI response and the Crab observations

The Crab region was observed several times by INTEGRAL for calibration purposes. This paper aims at underlining the systematic interactions between (i) observations of this reference source, (ii) in-flight calibration of the instrumental response and (iii) the development and validation of the analysis tools of the SPI spectrometer. It first describes the way the response is produced and how studies of the Crab spectrum lead to improvements and corrections in the initial response. Then, we present the tools which were developed to extract spectra from the SPI observation data and finally a Crab spectrum obtained with one of these methods, to show the agreement with previous experiments. We conclude with the work still ahead to understand residual uncertainties in the response.Comment: 4 pages, 4 figures, Proc. of the 5th INTEGRAL Workshop (Feb. 16-20 2004), to be published by ES

INTEGRAL broadband spectroscopy of Vela X-1

The wind-accreting X-ray binary pulsar and cyclotron line source Vela X-1 has been observed extensively during INTEGRAL Core Program observations of the Vela region in June-July and November-December 2003. In the latter set of observations the source showed intense flaring -- see also Staubert et al. (2004), these proceedings. We present early results on time averaged and time resolved spectra, of both epochs of observations. A cyclotron line feature at ~53 keV is clearly detected in the INTEGRAL spectra and its broad shape is resolved in SPI spectra. The remaining issues in the calibration of the instruments do not allow to resolve the question of the disputed line feature at 20-25 keV. During the first main flare the average luminosity increases by a factor of \~10, but the spectral shape remains very similar, except for a moderate softening.Comment: Accepted for proceedings of 5th INTEGRAL Worksho

Fault-controlled and stratabound dolostones in the Late Aptian-earliest Albian Benassal Formation (Maestrat Basin, E Spain) : petrology and geochemistry constrains

This study was developed under the ExxonMobil FC2 Alliance (Fundamental Controls on Flow in Carbonates). The authors wish to thank ExxonMobil Production Company and ExxonMobil Upstream Research Company for providing funding. The views in this article by Sherry L. Stafford are her own and not necessarily those of ExxonMobil. This research was supported by the Sedimentary Geology Research Group of the Generalitat de Catalunya (2014SGR251). We would like to thank Andrea Ceriani and Paola Ronchi for their critical and valuable reviews, and Associated Editor Piero Gianolla for the editorial work.Peer reviewedPostprin

L’Observation du Comportement du Nouveau-Ne: Une Source Pertinente d’Informations Medicales

L’observation du comportement du nouveau-né est une source importante d’informations d’ordre médical. Trois domaines bénéficient des données de l’observation : 1) l’analyse du développement grâce à l’utilisation de l’Assessment of Preterm Infant Behavior (évaluation du comportement de l’enfant prématuré) ; 2) l’évaluation de la douleur dominée par l’analyse de l’expression faciale grâce à des échelles validées, telle que le Neonatal Facial Coding System (système néonatal de codage facial) ; 3) la recherche de lésions cérébrales par le Quality Assessment of General Movements (évaluation de la qualité des mouvements généraux). L’observation comportementale fondée sur des outils validés par la recherche clinique constitue un complément utile des données de l’imagerie en période néonatale. The neonatal behavioral observation is an important source of medical informations in three domains: 1) assessment of development which can be done with the Assessment of Preterm Infant Behavior, 2) assessment of pain with the analysis of facial expression using validated pain scales such as the Neonatal Facial Coding System, 3) assessement of brain injuries with the Quality Assessment of General Movements. Such a behavioral observation of the newborn using validated tools is a useful complement of the neuro-imaging techniques

Influence of the Earth on the background and the sensitivity of the GRM and ECLAIRs instruments aboard the Chinese-French mission SVOM

SVOM (Space-based multi-band astronomical Variable Object Monitor) is a future Chinese-French satellite mission which is dedicated to Gamma-Ray Burst (GRB) studies. Its anti-solar pointing strategy makes the Earth cross the field of view of its payload every orbit. In this paper, we present the variations of the gamma-ray background of the two high energy instruments aboard SVOM, the Gamma-Ray Monitor (GRM) and ECLAIRs, as a function of the Earth position. We conclude with an estimate of the Earth influence on their sensitivity and their GRB detection capability.Comment: 24 pages, 15 figures, accepted for publication in Experimental Astronom

The INTEGRAL spectrometer SPI: performance of point-source data analysis

The performance of the SPI point-source data analysis system is assessed using a combination of simulations and of observations gathered during the first year of INTEGRAL operations. External error estimates are derived by comparing source positions and fluxes obtained from independent analyses. When the source detection significance provided by the spiros imaging reconstruction program increases from ∼10 to ∼100, the errors decrease as the inverse of the detection significance, with values from ∼10 to ∼1 arcmin in positions, and from ∼10 to ∼1 per cent in relative flux. These errors are dominated by Poisson counting noise. Our error estimates are consistent with those provided by the spiros program. With higher detection significance, the accuracy is ultimately limited to ∼0.5 arcmin in position and ∼1 per cent in relative flux by other types of errors. In these cases, spiros underestimates the true errors as it only takes into account the Poisson counting noise. At the low signal-to-noise ratio end, spiros is also too optimistic, and the number of spurious detections is significantly higher than would be expected from statistical noise fluctuations only. The analysis results do not depend significantly on the target off-axis angle, or on the number of pointings considered, provided that this number is larger than ∼15. Realistic source confusion tests are carried out by adding simulated data to the observation of the Crab nebula and pulsar. Reliable flux values can be obtained for sources separated by angles as small as 0.5 deg if their positions are known and kept fixed in the data deconvolution process. However, when spiros is searching for best source positions, if two sources are separated by less than ∼2 deg, it may only find a single spurious source located between the real ones (with a flux equal to the sum of the fluxes). Finally, users of the spiros program can find a number of important recommendations in the conclusio

Annihilation emission from young supernova remnants

A promising source of the positrons that contribute through annihilation to the diffuse Galactic 511keV emission is the beta-decay of unstable nuclei like 56Ni and 44Ti synthesised by massive stars and supernovae. Although a large fraction of these positrons annihilate in the ejecta of SNe/SNRs, no point-source of annihilation radiation appears in the INTEGRAL/SPI map of the 511keV emission. We exploit the absence of detectable annihilation emission from young local SNe/SNRs to derive constraints on the transport of MeV positrons inside SN/SNR ejecta and their escape into the CSM/ISM, both aspects being crucial to the understanding of the observed Galactic 511keV emission. We simulated 511keV lightcurves resulting from the annihilation of the decay positrons of 56Ni and 44Ti in SNe/SNRs and their surroundings using a simple model. We computed specific 511keV lightcurves for Cas A, Tycho, Kepler, SN1006, G1.9+0.3 and SN1987A, and compared these to the upper-limits derived from INTEGRAL/SPI observations. The predicted 511keV signals from positrons annihilating in the ejecta are below the sensitivity of the SPI instrument by several orders of magnitude, but the predicted 511keV signals for positrons escaping the ejecta and annihilating in the surrounding medium allowed to derive upper-limits on the positron escape fraction of ~13% for Cas A, ~12% for Tycho, ~30% for Kepler and ~33% for SN1006. The transport of ~MeV positrons inside SNe/SNRs cannot be constrained from current observations of the 511keV emission from these objects, but the limits obtained on their escape fraction are consistent with a nucleosynthesis origin of the positrons that give rise to the diffuse Galactic 511keV emission.Comment: 15 pages, 11 figures, accepted for publication in A&

NectarCAM : a camera for the medium size telescopes of the Cherenkov Telescope Array

NectarCAM is a camera proposed for the medium-sized telescopes of the Cherenkov Telescope Array (CTA) covering the central energy range of ~100 GeV to ~30 TeV. It has a modular design and is based on the NECTAr chip, at the heart of which is a GHz sampling Switched Capacitor Array and a 12-bit Analog to Digital converter. The camera will be equipped with 265 7-photomultiplier modules, covering a field of view of 8 degrees. Each module includes the photomultiplier bases, high voltage supply, pre-amplifier, trigger, readout and Ethernet transceiver. The recorded events last between a few nanoseconds and tens of nanoseconds. The camera trigger will be flexible so as to minimize the read-out dead-time of the NECTAr chips. NectarCAM is designed to sustain a data rate of more than 4 kHz with less than 5\% dead time. The camera concept, the design and tests of the various subcomponents and results of thermal and electrical prototypes are presented. The design includes the mechanical structure, cooling of the electronics, read-out, clock distribution, slow control, data-acquisition, triggering, monitoring and services.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589