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Magnetic Fields and Afterglows of BdHNe: Inferences from GRB 130427A, GRB 160509A, GRB 160625B, GRB 180728A, and GRB 190114C
Jorge Armando Rueda, Remo Ruffini, Mile Karlica, Rahim Moradi, Yu Wang, 2020, izvirni znanstveni članek

Opis: GRB 190114C is the first binary-driven hypernova (BdHN) fully observed from initial supernova (SN) appearance to the final emergence of the optical SN signal. It offers an unprecedented testing ground for the BdHN theory, which is here determined and further extended to additional gamma-ray bursts (GRBs). BdHNe comprise two subclasses of long GRBs, with progenitors a binary system composed of a carbon–oxygen star (COcore) and a neutron star (NS) companion. The COcore explodes as an SN, leaving at its center a newborn NS (νNS). The SN ejecta hypercritically accretes on both the νNS and the NS companion. BdHNe I are very tight binaries, where the accretion leads the companion NS to gravitationally collapse into a black hole (BH). In BdHN II, the accretion rate onto the NS is lower, so there is no BH formation. We observe the same afterglow structure for GRB 190114C and other selected examples of BdHNe I (GRB 130427A, GRB 160509A, GRB 160625B) and for BdHN II (GRB 180728A). In all cases, the afterglows are explained via the synchrotron emission powered by the νNS, and their magnetic field structures and their spin are determined. For BdHNe I, we discuss the properties of the magnetic field embedding the newborn BH, which was inherited from the collapsed NS and amplified during the gravitational collapse process, and surrounded by the SN ejecta.
Najdeno v: osebi
Ključne besede: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology
Objavljeno: 20.07.2020; Ogledov: 925; Prenosov: 0
.pdf Polno besedilo (1,37 MB)

On the GeV Emission of the Type I BdHN GRB 130427A
Laura Beccera, She Sheng Xue, Yu Wang, Narek Sahakyan, Mile Karlica, Yen-Chen Chen, Simonetta Filippi, Christian Cherubini, Carlo Luciano Bianco, Jorge Armando Rueda, Rahim Moradi, Remo Ruffini, 2019, izvirni znanstveni članek

Opis: We propose that the inner engine of a type I binary-driven hypernova (BdHN) is composed of Kerr black hole (BH) in a non-stationary state, embedded in a uniform magnetic field B_0 aligned with the BH rotation axis and surrounded by an ionized plasma of extremely low density of 10^−14 g cm−3. Using GRB 130427A as a prototype, we show that this inner engine acts in a sequence of elementary impulses. Electrons accelerate to ultrarelativistic energy near the BH horizon, propagating along the polar axis, θ = 0, where they can reach energies of ~10^18 eV, partially contributing to ultrahigh-energy cosmic rays. When propagating with $\theta \ne 0$ through the magnetic field B_0, they produce GeV and TeV radiation through synchroton emission. The mass of BH, M = 2.31M ⊙, its spin, α = 0.47, and the value of magnetic field B_0 = 3.48 × 10^10 G, are determined self consistently to fulfill the energetic and the transparency requirement. The repetition time of each elementary impulse of energy ${ \mathcal E }\sim {10}^{37}$ erg is ~10^−14 s at the beginning of the process, then slowly increases with time evolution. In principle, this "inner engine" can operate in a gamma-ray burst (GRB) for thousands of years. By scaling the BH mass and the magnetic field, the same inner engine can describe active galactic nuclei.
Najdeno v: osebi
Ključne besede: black hole physics, binaries, gamma-ray burst, neutron stars, supernovae, Astrophysics - High Energy Astrophysical Phenomena
Objavljeno: 20.07.2020; Ogledov: 1026; Prenosov: 0
.pdf Polno besedilo (1,09 MB)

Electromagnetic emission of white dwarf binary mergers
Jorge Armando Rueda, Remo Ruffini, Yu Wang, Carlo Luciano Bianco, J.M. Blanco-Iglesias, Mile Karlica, P. Lorén-Aguilar, Rahim Moradi, Narek Sahakyan, 2019, izvirni znanstveni članek

Opis: It has been recently proposed that the ejected matter from white dwarf (WD) binary mergers can produce transient, optical and infrared emission similar to the "kilonovae" of neutron star (NS) binary mergers. To confirm this we calculate the electromagnetic emission from WD-WD mergers and compare with kilonova observations. We simulate WD-WD mergers leading to a massive, fast rotating, highly magnetized WD with an adapted version of the smoothed-particle-hydrodynamics (SPH) code Phantom. We thus obtain initial conditions for the ejecta such as escape velocity, mass and initial position and distribution. The subsequent thermal and dynamical evolution of the ejecta is obtained by integrating the energy-conservation equation accounting for expansion cooling and a heating source given by the fallback accretion onto the newly-formed WD and its magneto-dipole radiation. We show that magnetospheric processes in the merger can lead to a prompt, short gamma-ray emission of up to ≈ 1046 erg in a timescale of 0.1-1 s. The bulk of the ejecta initially expands non-relativistically with velocity 0.01 c and then it accelerates to 0.1 c due to the injection of fallback accretion energy. The ejecta become transparent at optical wavelengths around ~ 7 days post-merger with a luminosity 1041-1042 erg s-1. The X-ray emission from the fallback accretion becomes visible around ~ 150-200 day post-merger with a luminosity of 1039 erg s-1. We also predict the post-merger time at which the central WD should appear as a pulsar depending on the value of the magnetic field and rotation period.
Najdeno v: osebi
Ključne besede: Astrophysics - High Energy Astrophysical Phenomena
Objavljeno: 20.07.2020; Ogledov: 944; Prenosov: 0
.pdf Polno besedilo (8,22 MB)

Ad-hoc and scalar implicatures in children with autism spectrum disorder
Luca Surian, Francesca Foppolo, Remo Job, Greta Mazzaggio, 2021, izvirni znanstveni članek

Opis: Previous studies found that people with Autism Spectrum Disorder (ASD) perform well on pragmatic inference tests that require the use of the linguistic scale . The present study extends previous research by testing two types of implicature: scalar implicatures, based on lexical scales, and ad-hoc implicatures, based on contextual scales. We tested 26 children with ASD aged 4–10 years (mean age 7.1) and 26 typically developing (TD) children – matched on chronological age and with a similar performance in non- verbal IQ and vocabulary – by means of a picture selection task for scalar and ad-hoc implica- tures. We also investigated the effect of children’s scores in standardized tests measuring non- verbal intelligence, lexical, and morphosyntactic abilities and Theory-of-Mind skills on their performance in the implicature tasks. Although more than half of the children with ASD performed above chance on both kinds of implicatures, their performance as a group was significantly lower than the performance of their TD peers. General cognitive abilities were found to affect the performance of children with ASD on both kinds of implicatures, and Theory-of-Mind reasoning skills were found to be linked to their performance on scalar, but not ad-hoc implicatures. We show that children with ASD have difficulty with both kinds of implicatures. These findings may have implications for explanatory theories of pragmatics as well as for clinical work with children with ASD.
Najdeno v: osebi
Ključne besede: experimental pragmatics, scalar implicatures, high-functioning autism, theory of mind, development
Objavljeno: 17.09.2021; Ogledov: 237; Prenosov: 0
.pdf Polno besedilo (4,08 MB)
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Greta Mazzaggio, Francesca Foppolo, Chiara Caretta, Remo Job, Luca Surian, 2017, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: Pragmatic abilities of people with Autism Spectrum Disorder (ASD) have been the subject of extensive research, often considering their communicative problems as derived from their deficit in Theory of Mind (ToM). On the other hand, recent studies on the derivation of scalar implicatures (SIs)– such as some but not all that are built on certain lexical items ordered in an entailment scale based on their informativeness, e.g. "some, all" − found no differences between typical population and people with ASD. With our work we find out that TD group’s performance was significantly better in the ad-hoc condition than the ASD’s, and both groups’ performance was related to Age. With respect to the SIs condition, the TD group’s performance was numerically better than the ASD group, but the difference was not significant, which may be due to a lack of power. Moreover, there is again a positive relationship between Age and SI performance, but only for the TD group. For the ASD group, there are positive relationships between SI performance and ToM as well as the linguistic syntactic measure. These relationships suggest that there is something different underlying the two groups’ performance in the SI condition. In computing SIs, ASD children seem to rely mainly on their syntactic linguistic abilities, which in turn are strongly connected with ToM skills; this connection can be related with the syntactic complexity of ToM’s clauses that involve subordination e.g. You believe that I believe that you believe. On the other hand, given that the best predictor for ad-hoc implicatures computation in ASD children is Age, we may suggest that indeed there is a delay in the development of pragmatic abilities in ASD children, also confirmed by the lower ToM scores in the ASD group. In conclusion, it seems that the computation of SIs and ad-hoc implicatures rests on different computational mechanisms and future research should take this insight into consideration.
Najdeno v: osebi
Ključne besede: theory of mind, scalar implicatures, adhoc implicatures, autism spectrum disorder
Objavljeno: 21.09.2021; Ogledov: 204; Prenosov: 7
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