549 research outputs found
Gamma-ray emission from Wolf-Rayet stars interacting with AGN jets
No full textDense populations of stars surround the nuclear regions of galaxies. Inthis work, we study the interaction of a WR star with relativistic jetsin active galactic nuclei. A bow-shaped double-shock structure will formas a consequence of the interaction of the jet and the wind of the star.Particles can be accelerated up to relativistic energies in these shocksand emit high-energy radiation. We compute the produced γ-ray emission obtaining that this radiation may be significant. This emissionis expected to be particularly relevant for nearby non-blazar sources.Fil: Araudo, Anabella Teresa. Centro de Radioastronomía y Astrofísica. Unam; MéxicoFil: Valenti Bosch-Ramon. Universidad de Barcelona; EspañaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentina5th International Meeting on High Energy Gamma-Ray AstronomyHeidelbergAlemaniaMax-Planck-Institute for Nuclear Physic
High-energy flares from jet-clump interactions
No full textHigh-mass microquasars are binary systems composed by a massive star and a compact object from which relativistic jets are launched. Regarding the companion star, observational evidence supports the idea that winds of hot stars are formed by clumps. Then, these inhomogeneities may interact with the jets producing a flaring activity. In the present contribution we study the interaction between a jet and a clump of the stellar wind in a high-mass microquasar. This interaction produces a shock in the jet, where particles may be accelerated up to relativistic energies. We calculate the spectral energy distributions of the dominant non-thermal processes: synchrotron radiation, inverse Compton scattering, and proton-proton collisions. Significant levels of X- and γ-ray emission are predicted, with luminosities in the different domains up to ∼1034–1035 erg s-1 on a timescale of about ∼1 h. Finally, jet-clump interactions in high-mass microquasars could be detectable at high energies. These phenomena may be behind the fast TeV variability found in some high-mass X-ray binary systems, such as Cygnus X-1, LS 5039 and LS I+61 303. In addition, our model can help to derive information on the properties of jets and clumpy winds.Fil: Araudo, Anabella Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto Argentino de Radioastronomia (i); Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Bosch Ramon, Valenti. Max Planck Institut fur Kernphysik, Heidelberg; AlemaniaFil: Romero, Gustavo Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto Argentino de Radioastronomia (i); Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentin
Gamma-rays from massive protostars
No full textMassive protostars have associated bipolar outflows with velocities of hundreds of km s-1. Such outflows produce strong shocks when interact with the ambient medium leading to regions of non-thermal radio emission. Under certain conditions, the population of relativistic particles accelerated at the terminal shocks of the protostellar jets can produce significant gamma-ray emission. We estimate the conditions necessary for high-energy emission in the non-thermal hot spots of jets associated with massive protostars embedded in dense molecular clouds. Our results show that particle-matter interactions can lead to the detection of molecular clouds hosting massive young stellar objects by the Fermi satellite at MeV-GeV energies and even by Cherenkov telescope arrays in the GeV-TeV range. Astronomy at gamma-rays can be used to probe the physical conditions in star forming regions and particle acceleration processes in the complex environment of massive molecular clouds.Fil: Romero, Gustavo Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto Argentino de Radioastronomia (i); Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Araudo, Anabella Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto Argentino de Radioastronomia (i); Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Bosch Ramon, Valenti. Max Planck Institut fur Kernphysik; AlemaniaFil: Paredes, Josep María. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de Ciéncies del Cosmos; Españ
Low-frequency radio observations of the MGRO J2019+37 Complex
No full textWe present here a preliminary account of the results of a wide-field mosaic obtained at 610 MHz (49 cm) with the Giant Metre-wave Radio Telescope (GMRT) in India covering the field of the unidentified TeV source MGRO J2019+37. A catalogue of all radio sources detected has been created including both compact and extended objects. Their observational properties are described and presented. We draw the attention to some peculiar objects inside the ˜1° uncertainty region of the TeV emission. The possible connection of these sources with the MILAGRO γ-ray emission will be assessed in future work.Fil: Sánchez Sutil, Juan R. . Universidad de Jaén; EspañaFil: Paredes, Josep M.. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de Ciències del Cosmos; EspañaFil: Moldón, J.. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de Ciències del Cosmos; EspañaFil: Zabalza, V.. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de Ciències del Cosmos; EspañaFil: Bordas, P.. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de Ciències del Cosmos; EspañaFil: Ribó, M.. Universitat de Barcelona. Departament d’Astronomia i Meteorologia and Institut de Ciències del Cosmos; EspañaFil: Martí, Josep. Universidad de Jaén; EspañaFil: Muñoz Arjonilla, Alvaro J.. Universidad de Jaén; EspañaFil: Luque Escamilla, Pedro L.. Universidad de Jaén; EspañaFil: Ishwara Chandra, C. H.. NCRA. TIFR; IndiaFil: Peracaula, Marta. Universidad de Girona; EspañaFil: Bosch Ramon, Valenti. Max Planck Institut Fur Kernphysik, Heidelberg; AlemaniaFil: Romero, Gustavo Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto Argentino de Radioastronomia (i); Argentin
The role of supernovae inside AGN jets in UHECR acceleration
No full textJets of active galactic nuclei are potential accelerators of ultra
high-energy cosmic rays. Supernovae can occur inside these jets and contribute
to cosmic ray acceleration, particularly of heavy nuclei, but that contribution
has been hardly investigated so far. We carried out a first dedicated
exploration of the role of supernovae inside extragalactic jets in the
production of ultra high-energy cosmic rays. We characterized the energy budget
of supernova-jet interactions, and the maximum possible energies of the
particles accelerated in those events, likely dominated by heavy nuclei. This
allowed us to assess whether these interactions can be potential acceleration
sites of ultra high-energy cosmic rays, or at least of their seeds. For that,
we estimated the cosmic ray luminosity for different galaxy types, and compared
the injection rate of cosmic ray seeds into the jet with that due to galactic
cosmic ray entrainment. Since the supernova is fueled for a long time by the
luminosity of the jet, the energy of a supernova-jet interaction can be several
orders of magnitude greater than that of an isolated supernova. Thus, despite
the low rate of supernovae expected to occur in the jet, they could still
provide more seeds for accelerating ultra high-energy particles than cosmic ray
entrainment from the host galaxy. Moreover, these interactions can create
sufficiently efficient accelerators to be a source of cosmic rays with energies
~EeV. Supernova-jet interactions can contribute significantly to
the production of ultra high-energy cosmic rays, either directly by
accelerating these particles themselves or indirectly by providing
pre-accelerated seeds.Comment: 4 pages, Letter accepted for publication in Astronomy and
Astrophysics (in press
Rinnovazione dell'istruttoria dibattimentale in appello: Corte europea e Corte di cassazione a confronto
No full textCommentando la sentenza pronunciata dalla Corte europea dei diritti dell’uomo nel caso “Tondo contro Italia”, l’autore esamina il diverso approccio della Corte di Strasburgo e della Corte di
cassazione al tema della rinnovazione dell’istruttoria dibattimentale in appello.Commenting on the judgment of the European Court of Human Rights in the “Tondo v. Italy” case, the author
examines the different approach of the Strasbourg Court and the Court of Cassation to the theme of renewing of the appeal hearing
Riflessioni a margine di una proposta di legge sulla liberazione anticipata
No full textThe author examines the bill AC 552 presented by MP Giachetti on the subject of early releases. In particular, he addresses the critical issues of the proposal, both theoretical and practical, in order to contribute to the elimination or correction of its systematic defects
La tutela della professionalità nel mercato del lavoro che cambia
No full textIl saggio sottolinea l'importanza dello sviluppo professionale dei lavoratori alla luce dei processi di digitalizzazione in atto, spaziando dall'analisi dell'attuale contesto socio-economico alle recenti misure normative per il rafforzamento dell'occupabilità. A tal proposito, l'autore suggerisce l'esistenza di approcci sia passivi che attivi alla formazione continua dei lavoratori nell'attuale quadro giuridico, descrivendo i più recenti strumenti giuridici volti a salvaguardare la stabilità occupazionale attraverso percorsi di upskilling e reskilling.The essay emphasizes the importance of professional development for workers in the light of the ongoing digitalization processes, spacing from the analysis of the present socio-economic context to the recent regulatory measures for the strengthening of employability. In this respect, the author suggests the existence of both passive and active approaches to continuous training of employees in the current juridical framework by describing the latest legal instruments designed to safeguard employment stability through upskilling and reskilling pathways
La «incostituzionalità delle Sezioni unite Iannelli» e l'interesse ad impugnare del pubblico ministero
No full textLo scritto commenta una decisione con la quale la Corte di cassazione ha ritenuto che la declaratoria di illegittimità costituzionale dell’art. 568, comma 4, c.p.p., pronunciata con la sentenza n. 111 del 2022, trovi applicazione anche all’impugnazione del pubblico ministero, ferma restando la necessità di accertare, sulla base della prospettazione del ricorso, la sussistenza di un concreto interesse ad impugnare. L’autore ritiene corretta quest’ultima soluzione e non condivisibile la prima.The writing comments on a decision with which the Court of Cassation argued that the declaration of constitutional illegitimacy of the art. 568 par. 4 of the Code of Criminal Procedure, pronounced with sentence no. 111 of 2022, also applies to the public prosecutor’s appeal. However, the existence of a concrete interest in appealing must be ascertained by examining what is highlighted in the appeal. The author believes that this last solution is correct and that the first is not acceptable
La valutazione prognostica nel giudizio di sorveglianza: limiti, ricadute, prospettive. Il caso dei sex offenders
No full textIl saggio pone la questione dell’idoneità della magistratura di sorveglianza, nell’assetto attuale, a formulare valutazioni in punto di meritevolezza dei “benefici penitenziari”. La disamina viene condotta muovendo dal settore – connotato da elevata complessità psico-criminologica – degli autori di reati che ledono la sfera sessuale e si sviluppa affrontando una serie di intricate sotto-questioni, che vanno dal tipo di controllo del giudice sulle risultanze prodotte dagli “esperti” dell’equipe trattamentale al grado di “specializzazione” del tribunale di sorveglianza. Ricostruito un quadro che restituisce l’immagine di una giurisdizione sempre meno attrezzata a formulare quei giudizi prognostici, e messe in luce le potenziali ricadute di tale disfunzione sul ragionamento decisorio, ci si chiede se l’avvertita esigenza di un rafforzamento delle basi “scientifiche” di quei giudizi possa essere soddisfatta dall’intelligenza artificiale. Dal momento che questa analisi, attualmente, non conduce ad esiti appaganti, si suggeriscono altri correttivi, tra cui l’istituzione dell’“assistente specializzato”, e, con essa, la costruzione di una equipe (multidisciplinare) della magistratura di sorveglianza.The essay questions the adequacy of the current set-up of the Supervisory Judiciary overseeing the execution of sentences to decide on the granting of measures aimed at the social reintegration of prisoners. In particular, the analysis focuses on assessments related to sex offenders, which are characterized by special complexity. The examination is conducted by addressing a series of intricate sub-questions: from the type of judicial control over the findings produced by the experts from the prison’s treatment group to the degree of “specialization” of the Supervisory Court. After clarifying that the Supervisory Jurisdiction are less and less technically equipped to make those prognostic judgments, and after pointing out the potential fallout of this dysfunction on the judicial decision making, the author questions whether the need for expert knowledge can be met by artificial intelligence. This analysis does not currently lead to fulfilling outcomes. Therefore, the author suggests other correctives: among them, the establishment of the “Specialized Assistant”, and thus the construction of a (multidisciplinary) team of the Supervisory Judiciary
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