Galactic sources science with AGILE: The case of the Carina Region Sabatini, S.; Tavani, M.; Pian, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2011, Letnik:
630, Številka:
1
Journal Article
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During its first 2 years of operation, the gamma-ray AGILE satellite accumulated an extensive dataset for the Galactic plane. The data have been monitored for transient sources and several gamma-ray ...sources were detected. Their variability and possible association were studied. In this talk we will focus on the results of extensive observations of the Carina Region during the time period 2007 July–2009 January, for a total livetime of
∼
130
days. The region is extremely complex, hosting massive star formation, with the remarkable colliding wind binary Eta Carinae, massive star clusters and HII regions (e.g. NGC 3324, RCW49, Westerlund II) and a giant molecular cloud extending over 150 pc (between
l=284.7 and 289). The Carina Nebula itself is the largest and IR highest surface brightness nebula of the Southern emisphere. We monitored several gamma ray sources in the Carina Region. In particular we detect a gamma ray source (1AGL J1043-5931) consistent with the position of Eta Carinae and report a remarkable 2-days gamma-ray flaring episode from this source on 2008 October 11–13. If 1AGL J1043-5931 is associated with the Eta Car system, our data provide the long sought first detection above 100
MeV of a colliding wind binary.
Super-massive black holes in active galaxies can accelerate particles to relativistic energies, producing jets with associated g-ray emission. Galactic 'microquasars', which are binary systems ...consisting of a neutron star or stellar-mass black hole accreting gas from a companion star, also produce relativistic jets, generally together with radio flares. Apart from an isolated event detected in CygnusX-1, there has hitherto been no systematic evidence for the acceleration of particles to gigaelectronvolt or higher energies in a microquasar, with the consequence that we are as yet unsure about the mechanism of jet energization. Here we report four g-ray flares with energies above 100MeV from the microquasar CygnusX-3 (an exceptional X-ray binary that sporadically produces radio jets). There is a clear pattern of temporal correlations between the g-ray flares and transitional spectral states of the radio-frequency and X-ray emission. Particle acceleration occurred a few days before radio-jet ejections for two of the four flares, meaning that the process of jet formation implies the production of very energetic particles. In CygnusX-3, particle energies during the flares can be thousands of times higher than during quiescent states.
SuperAGILE is the X-ray monitor of AGILE, the small space mission of the Italian Space Agency (ASI) devoted to observations for astrophysics in the gamma ray energy range 30 MeV-50 GeV. SuperAGILE ...exploits an additional layer of four silicon micro-strip detectors for 1360 cm/sup 2/ of total geometrical area, readout by low power ASICs, and four mutually orthogonal ultra-light one-dimensional coded mask to monitor the X-ray sky in the 15-40 keV energy band. The engineering model of the payload has been built and tested, and the construction of the flight model is starting. We present here the status of SuperAGILE. We show its design, the construction, the alignment and the results of testing campaigns carried out on the engineering model.
The fragmentation of the CH
4
2+ dication has been studied in an electron impact experiment by Auger electron-ion and Auger electron-ion–ion coincidence measurements. Different states of the ...dications have been selected by changing the kinetic energy of the Auger electrons. Particular attention has been paid to the production of the CH
2
+ and CH
3
+ ions whose Kinetic Energy Release (KER) distributions and dissociation channels have been determined. Moreover, for the first time in an electron impact experiment, the C
2+ ion fragment has been identified.
Temporary epicardial pacing wires are commonly placed in patients undergoing surgery for congenital heart disease. Though often helpful, these wires are not without risk. We aimed to identify ...characteristics that would obviate placement of temporary epicardial pacing wires in this patient population.
A prospective observational study was performed on patients admitted to the pediatric intensive care unit after surgery for congenital heart disease between October 2011 and October 2012. Logistic regression analysis was performed to identify independent predictors of patients in whom wires were not helpful postoperatively.
Wires were placed in 213 of 249 patients. Wires were helpful in 50 patients; 23 for diagnostic purposes only, 17 for therapeutic purposes only, and 10 for both. On logistic regression analysis, absence of intraoperative arrhythmias (p < 0.01), lower arteriovenous O2 difference (p < 0.01), and shorter duration of cardiopulmonary bypass (p = 0.050) were significant predictors of patients in whom wires were not helpful postoperatively. Further, the predicted probability based on logistic regression model using these 3 variables correctly identified 93% of patients who did not need pacing wires. Four complications (1.9%) related to wires occurred, including 1 episode of life-threatening bleeding that was found, during emergent exploration, to be due to atrial perforation at the wire insertion site.
Temporary epicardial pacing wires are not necessary in many patients recovering from surgery for congenital heart disease. A conservative approach to their use may therefore be warranted.
Abstract Background Among currently available surgical options for the first stage of surgery for infants with hypoplastic left heart syndrome (HLHS), the hybrid procedure is relatively new and less ...well known among primary care and emergency physicians. This procedure involves placement of a stent within the ductus arteriosus to maintain systemic blood flow and bands around both pulmonary arteries to prevent pulmonary overcirculation. As the number of infants undergoing this procedure increases, emergency physicians will likely encounter them in their practice and should be familiar with their unique physiology and potential complications. Objectives Review various emergency department (ED) presentations and management of a patient after the hybrid procedure. Case Report A 4-month-old male infant with HLHS who had undergone an uncomplicated hybrid procedure in the neonatal period presented to a community ED with severe metabolic acidosis and poor perfusion. He was intubated and received mechanical ventilation with an inspired oxygen concentration of 60%. Initial capillary blood gas revealed PO2 59 torr, which, in the context of his clinical presentation, was suggestive of pulmonary overcirculation with “systemic steal.” Approximately 60 min after presentation to the ED, he experienced a bradycardic arrest. He expired 40 min later. Conclusion This case highlights the potential of infants who undergo the hybrid procedure for HLHS to present to the ED with high acuity and, accordingly, the importance of adding this disease process to the vast burden of knowledge facing ED physicians.
Radiation-induced effects on the XAA1.2 ASIC chip for space application Del Monte, Ettore; Pacciani, Luigi; Porrovecchio, Geiland ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2005, Letnik:
538, Številka:
1
Journal Article
Recenzirano
The XAA1.2 is a custom ASIC chip for space applications built using a
0.8
μ
m
complementary metal oxide semiconductor technology on epitaxial layer. It has been selected as the front-end electronics ...chip of the SuperAGILE experiment on board the AGILE space mission, although it is not specifically designed as a radiation hard device. To study the XAA1.2 sensitivity to Single Event Effects and Total Dose Effects we irradiate this chip at the SIRAD facility of the
Laboratori Nazionali INFN of Legnaro. In this paper we describe the experimental set-up and the measurements. We then discuss how the results can be scaled to the cosmic rays environment in a low-Earth orbit.
This study shows the feasibility of the introduction of Al 2 O 3 nanoparticles by mechanical alloying in a near eutectic Ag-3,5Sn solder alloy. Different weight percents of Al 2 O 3 were dispersed ...and the resulting microstructures were analyzed using optical and electronic microscopy and X-ray diffraction. The alloys with 1 and 5 wt% have shown excellent results regarding nanoparticle dispersion and microstructure homogeneity after 100h of high energy milling.
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