1,355,107 research outputs found
Gamma-Ray Astronomy with Cherenkov TelescopesAIP Conference Proceedings
No full textThe γ-astronomy with Cherenkov telescope has recently made great progress coming to the 2nd generation of instruments. The higher sensitivity and lower energy threshold have brought to discover new sources. The determination of their spectra, necessary for developing models for acceleration, emission and absorption of the γ-rays, will shed new light on the century-old problem of the origin of galactic cosmic rays. A short summary of the current physics objectives in the γ-astronomy and a description of the Cherenkov telescopes technique is given. Some representative observations from the two operative telescopes, HESS and MAGIC are described. © 2005 American Institute of Physics
A new method to unveil blazars among multiwavelength counterparts of unassociated Fermi γ-ray sources
No full textWe discuss a new method for unveiling the possible blazar active galactic nucleus nature among the numerous populations of unassociated gamma-ray sources (UGSs) in the Fermi catalogues. Our tool relies on the positional correspondence of the Fermi object with X-ray sources (mostly from Swift-XRT), correlated with other radio, infrared and optical data in the field. We built a set of spectral energy distribution templates representative of the various blazar classes, and we quantitatively compared them to the observed multiwavelength flux density data for all Swift-XRT sources found within the Fermi error box, by taking advantage of some well-recognized regularities in the broad-band spectral properties of the objects. We tested the procedure by comparison with a few well-known blazars, and tested the chance for false-positive recognition of UGSs against known pulsars and other Galactic and extragalactic sources. Based on our spectral recognition tool, we find the blazar candidate counterparts for 14 2FGL UGSs among 183 selected at high galactic latitudes. Furthermore, our tool also allows us to obtain rough estimates of the redshift for the candidate blazar. In a few cases in which this has been possible (I.e. when the counterpart was an SDSS object), we verified that our estimate is consistent with the measured redshift. The estimated redshifts of the proposed UGS counterparts are larger, on average, than those of known Fermi blazars, a fact that might explain the lack of previous association or identification in published catalogues
La cittadinanza digitale e le insidie della rete: profili civili e penali dei rapporti tra gli utenti del web
No full textA model for periodic blazars
No full textWe describe a scenario to explain blazar periodicities with time-scales of similar to few years. The scenario is based on a binary supermassive black hole (SMBH) system in which one of the two SMBHs carries a jet. We discuss the various mechanisms that can cause the jet to precess and produce corkscrew patterns through space with a scale of similar to few pc. It turns out that the dominant mechanism responsible for the precession is simply the imprint of the jet-carrying SMBH orbital speed on the jet. Gravitational deflection and Lense-Thirring precession (due to the gravitational field of the other SMBH) are second-order effects. We complement the scenario with a kinematical jet model which is inspired to the spine-sheath structure observed in M87. One of the main advantages of such a structure is that it allows the peak of the synchrotron emission to scale with frequency according to nu F alpha nu(xi) as the viewing angle is changed, where. is not necessarily 3 or 4 as in the case of jets with uniform velocity, but can be xi similar to 1. Finally, we apply the model to the source PG1553+113, which has been recently claimed to show a T-obs = (2.18 +/- 0.08) yr periodicity. We are able to reproduce the optical and gamma-ray light curves and multiple synchrotron spectra simultaneously. We also give estimates of the source mass and size
A MAGIC view of the Very High-Energy gamma-Ray Sky.
No full textMAGIC is currently the largest single dish Cherenkov telescope operating since September 2004. Since then it has been delivering a wealth of exciting physics results from its observations in the Very High Energy (VHE) region of galactic and extragalactic sky. We present a review of the most recent experimental results obtained using MAGIC
Astreintes and Italian Law
No full textThis essay analyses the transposition path into Italian law of the French measure of astreintes, which are an indirect coercive method aimed to force the debtor to fulfill the obligation. The modern configuration has led to the adoption of judgments such as the one related to the “Case Facebook” (Order of the Court of Reggio Emilia, 15 April 2015), involving the urgency protection provided by art. 700 c.c.p. relatively to the hypothesis of defamation on Facebook or other Social Networking Sites. The astreinte find an equal in the Anglo-Saxon sort, by the contempt of court, and in the German one, through the Zwangsstrafen, which led, after several transposition attempts into national law (among which stands out the “Project Carnelutti” of 1926), to the current forecast referred to art. 614 bis c.c.p., introduced by art. 49 of Law 18 June 2009 n. 69. An application issue of the astreinte in Italy concerns its potential struggle with the internal public order: in Italy, there isn’t any provision of punitive damages outlined in common law systems, so that their transposition would lead to a worsening of the obliged subject's position, in contrast with the proportionality principle on which is based the
compensation statement system. The Italian Supreme Court, by the judgment of 15 April 2015 n. 7283, expresses itself in the opposite direction, stating that “the astreintes provided in other jurisdictions [...] are not incompatible with the Italian public policy”. The contemporary Italian law framework, based on the right of “forced execution”, which one can deduct from the art. 24 of the Constitution (which states that all may take legal action for protecting their rights and legitimate interests), is outlined from the Book III, Title IV of the Italian Code of Civil Procedure, indexed “the enforcement of proactive or passive obligations”, Articles 612 to 614 bis c.c.p., where it is possible to involve, from the address of the art. 614 bis c.c.p., the irreplaceable
performance, although the same rule has generated several disputes. To underline the value and the transverse projection of the theme, it is proper to highlight the inapplicability of Article 614 bis c.c.p. to individual work disputes listed in art. 409 c.c.p. This exclusion, unjustified and irrational, strongly undermines the principle of equality safeguarded by the art. 3 of the Italian Constitutional Charter, and has given rise to an abundant doctrine that considered art. 614 bis c.c.p., if applied, an extra protection to the right to work contemplated by the art. 4 of the Constitution, and even by art. 18 L. 20 May 1970 n. 300. In this perspective, the art. 614 bis make up a missed opportunity for the code of civil procedure to ensure an executive procedural protection for both parties of the employment contract. The possible reconstructions related to
debtor's indirect coercion shows problematic aspects referring to a potential overlap with ordinary protection instruments provided by Articles 1223 c.c., indexed “compensation of the damage”, and 2932 c.c., indexed “specific execution of the obligation to close a contract”, which, for certain doctrine, would be posed after the means provided by art. 614 bis c.c.p. In this way, the executive safeguards to the damage resulting from the breach would be erroneously duplicated. For certain doctrine, this impasse could be overcome by the second
paragraph of this Article, with a factual assessment, carried out by the Court, of the abovementioned principle of irreplaceability, excluding its application to all those obligations deprived of such connotation. Some doctrine opposed another configuration, endorsed by the jurisprudence, which postulates a systematic and teleological interpretation, per which it would be possible to extend such protection independently from a postulate of irreplaceability. In this scenario, the research will, at last, offer an interesting train of thought to the debate on legal affairs in the perspective of a possible future and further reform of the civil execution law, also taking into consideration to transpose into Italian Law an institute inspired by punitive damages and based on the penal principle of rehabilitation function of punishment (rectius, in this case, of execution) referred to art. 27 subparagraph 3 of the Italian Constitution
L'attuale estensione applicativa dell'art. 614 bis del c.p.c. - Profili di analisi nel diritto comparato, nel diritto del lavoro e nel diritto civile
No full textL'applicazione del privilegio generale mobiliare ai crediti dell'impresa artigiana ex art. 2751 bis n.5 c.c.: i confini lavoristici e commerciali
No full textIl complesso e variegato panorama dei privilegi del credito, caratterizzato nella sua conformazione odierna da un particolarismo legislativo dovuto al proliferare di norme speciali susseguitesi nel tempo, si presta ad una diffusa applicazione nell’ambito del diritto delle procedure concorsuali e dell’esecuzione civile. Scopo del presente saggio è di analizzare l’ancora attuale preponderanza dei principi di prevalenza e preminenza di cui all’art.2083 c.c. al di la delle previsioni della legge fallimentare, della normativa speciale di settore e dei principi generali lavoristici in materia. Nonostante la novella della L. 4.4.2012 n.35, infatti, ancora oggi risulta necessaria un’opera ermeneutica di interpretazione sistematica al fine di ricostruire la definizione di “impresa artigiana” per determinare l’ambito di applicabilità del privilegio generale mobiliare previsto dall’art.2751bis, n.5, c.c., come ulteriormente ribadito dalla sentenza della Corte di cassazione 20.3.2015 n.5685
- …
