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Search Results: 1 - 10 of 144500 matches for " F. Orio "
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SSS in young stellar populations and the "prompt" component of Type Ia supernovae
T. Nelson,M. Orio,F. Di Mille
Physics , 2009, DOI: 10.1002/asna.200911331
Abstract: We present the results of a search for UV and optical counterparts of the SSS population in M31. We find that out of the 56 sources we included in our search, 16 are associated with regions of ongoing or recent star formation. We discuss two particularly interesting sources that are identified optically as early type stars, one of which displayed long term X-ray evolution similar to that observed in classical novae. We discuss the physical origin of supersoft X-rays in these and the other SSS in young regions, and their possible link to the so-called "prompt" component of the Type Ia supernova population.
Multiwavelength search for counterparts of supersoft X-ray sources in M31
E. Chiosi,M. Orio,F. Bernardini,M. Henze,N. Jamialiahmadi
Physics , 2014, DOI: 10.1093/mnras/stu1145
Abstract: We searched optical/UV/IR counterparts of seven supersoft X-ray sources (SSS) in M31 in the Hubble Space Telescope (HST) "Panchromatic Hubble Andromeda Treasury" (PHAT) archival images and photometric catalog. Three of the SSS were transient, the other four are persistent sources. The PHAT offers the opportunity to identify SSS hosting very massive white dwarfs that may explode as type Ia supernovae in single degenerate binaries, with magnitudes and color indexes typical of symbiotic stars, high mass close binaries, or systems with optically luminous accretion disks. We find evidence that the transient SSS were classical or recurrent novae; two likely counterparts we identified are probably symbiotic binaries undergoing mass transfer at a very high rate. There is a candidate accreting white dwarf binary in the error circle of one of the persistent sources, r3-8. In the spatial error circle of the best studied SSS in M31, r2-12, no red giants or AGB stars are sufficiently luminous in the optical and UV bands to be symbiotic systems hosting an accreting and hydrogen burning white dwarf. This SSS has a known modulation of the X-ray flux with a 217.7 s period, and we measured an upper limit on its derivative, 0.82 x 10(-11). This limit can be reconciled with the rotation period of a white dwarf accreting at high rate in a binary with a few-hours orbital period. However, there is no luminous counterpart with color indexes typical of an accretion disk irradiated by a hot central source. Adopting a semi-empirical relationship, the upper limit for the disk optical luminosity implies an upper limit of only 169 minutes for the orbital period of the white dwarf binary.
Corporate and State Social Responsibility: A Long-Term Perspective  [PDF]
Rosetta Lombardo, Giovanni D’Orio
Modern Economy (ME) , 2012, DOI: 10.4236/me.2012.31013
Abstract: Companies have caught the changes in consumer perceptions and have developed corporate social responsibility (CSR) as long run survival strategy. The CSR signals that companies are overcoming the logic of the short term. The question is whether an evolution towards something similar that we call State social responsibility (SSR) is possible. State social responsibility is exerted when the State, in absence (or in case of ineffectiveness) of a formal supranational law, protects the rights of current and future generations of its citizens and citizens of other states and/or raises the current generations’ awareness regarding the opportunities reduction generated in space and time by meta-externalities. States would signal the tendency to overcome their short-sighted logic if the meta-externalities became a crucial question in their agenda.
X-ray observations of classical and recurrent novae in Outburst
M. Orio
Revista mexicana de astronomía y astrofísica , 2004,
Abstract:
Counter-Aging in the Post-industrial Society
Orio Giarini
Cadmus , 2012,
Abstract:
Science and Economics: The Case of Uncertainty & Disequilibrium
Orio Giarini
Cadmus , 2011,
Abstract:
Updating macro-economics
Orio Giarini
Cadmus , 2010,
Abstract:
Observations of Classical and Recurrent Novae with X-ray Gratings
Marina Orio
Physics , 2012,
Abstract: X-ray grating spectra have opened a new window on the nova physics. High signal-to-noise spectra have been obtained for 12 novae after the outburst in the last 13 years with the Chandra and XMM-Newton gratings. They offer the only way to probe the temperature, effective gravity and chemical composition of the hydrogen burning white dwarf before it turns off. These spectra also allow an analysis of the ejecta, which can be photoionized by the hot white dwarf, but more often seem to undergo collisional ionization. The long observations required for the gratings have revealed semi-regular and irregular variability in X-ray flux and spectra. Large short term variability is especially evident in the first weeks after the ejecta have become transparent to the central supersoft X-ray source. Thanks to Chandra and XMM-Newton, we have discovered violent phenomena in the ejecta, discrete shell ejection, and clumpy emission regions. As expected, we have also unveiled the white dwarf characteristics. The peak white dwarf effective temperature in the targets of our samples varies between ~400,000 K and over a million K, with most cases closer to the upper end, although for two novae only upper limits around 200,000 K were obtained. A combination of results from different X-ray satellites and instruments, including Swift and ROSAT, shows that the shorter is the supersoft X-ray phase, the lower is the white dwarf peak effective temperature, consistently with theoretical predictions. The peak temperature is also inversely correlated with t(2) the time for a decay by 2 mag in optical. I strongly advocate the use of white dwarf atmospheric models to obtain a coherent physical picture of the hydrogen burning process and of the surrounding ejecta.
A NuSTAR observation of the fast symbiotic nova V745 Sco in outburst
M. Orio,V. Rana,K. L. Page,J. L. Sokoloski,F. Harrison
Physics , 2014, DOI: 10.1093/mnrasl/slu195
Abstract: The fast recurrent nova V745 Sco was observed in the 3-79 keV X-rays band with NuSTAR 10 days after the optical discovery. The measured X-ray emission is consistent with a collisionally ionized optically thin plasma at temperature of about 2.7 keV. A prominent iron line observed at 6.7 keV does not require enhanced iron in the ejecta. We attribute the X-ray flux to shocked circumstellar material. No X-ray emission was observed at energies above 20 keV, and the flux in the 3-20 keV range was about 1.6 $\times$ 10$^{-11}$ erg cm$^{-2}$ s$^{-1}$. The emission measure indicates an average electron density of order of 10$^7$ cm$^{-3}$. The X-ray flux in the 0.3-10 keV band almost simultaneously measured with Swift was about 40 times larger, mainly due to the luminous central supersoft source emitting at energy below 1 keV. The fact that the NuSTAR spectrum cannot be fitted with a power law, and the lack of hard X-ray emission, allow us to rule out Comptonized gamma rays, and to place an upper limit of the order of 10$^{-11}$ erg cm$^{-2}$ s$^{-1}$ on the gamma-ray flux of the nova on the tenth day of the outburst.
An assembly line for the construction of ultra-pure detectors
A. Buccheri,M. Capodiferro,S. Morganti,F. Orio,A. Pelosi,V. Pettinacci
Physics , 2014,
Abstract: The 19 towers constituting the CUORE detector are an assembly of ultra-radio-pure components made of copper and PTFE plus tellurium dioxide crystals for a total of more than 10,000 pieces. A dedicated assembly line is mandatory to handle and assembly those parts minimizing the risk of recontaminations induced by external agents both during their construction and their storage prior to installation inside the cryostat. The assembly strategy and the tools design, proposed in this paper and developed for CUORE, offer solutions that can be extended to the construction of similar-size detector with strict requirements on contamination.
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