325,261 research outputs found
Charles S. Zane
No full textCharles S. Zane (1831-1915) came to Salt Lake City in 1884 and served as a judge over the Third Judicial District. He was tough on polygamy and convicted many prominent Utahns for illegal cohabitation
Charles S. Zane
No full textCharles S. Zane (1831-1915) came to Salt Lake City in 1884 and served as a judge over the Third Judicial District. He was tough on polygamy and convicted many prominent Utahns for illegal cohabitation
Proton cyclotron features in thermal spectra of ultramagnetized neutron stars
No full textA great deal of interest has been recently raised in connection with the possibility that soft gamma -ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) contain magnetars, young neutron stars endowed with magnetic fields greater than or similar to 10(14) G. In this paper we calculate thermal spectra from ultramagnetized neutron stars for values of the luminosity and magnetic field believed to be relevant to SGRs and AXPs. Emergent spectra are found to be very close to a blackbody at the star effective temperature and exhibit a distinctive absorption feature at the proton cyclotron energy E-c,E-p similar or equal to 0.63(B/10(14) G) keV. The proton cyclotron features (PCFs) are conspicuous (equivalent width of up to many hundreds eV) and relatively broad (DeltaE/E similar to0.05-0.2). The detection of the PCFs is well within the capabilities of present X-ray spectrometers, like the HETGS and METGS on board Chandra. Their observation might provide decisive evidence in favor of the existence of magnetars
Timing analysis of the isolated neutron star RX J0720.4-3125 revisited
No full textWe present a reanalysis of the X-ray data for RX J0720.4-3125 presented in our previous paper, Zane et al., using more data recently available from XMM-Newton and Chandra. This analysis also corrects the ROSAT data used in that paper to the barycentric dynamical time (TDB) system, incorporates the revised XMM-Newton barycentric correction available since then, and corrects the definition of the instantaneous period in the maximum likelihood periodogram search. However, we are now unable to find a single coherent period that is consistent with all ROSAT, Chandra and XMM-Newton data sets. From an analysis of the separate data sets, we have derived limits on the period change of (P)over dot = (1.4 +/- 0.6) x 10(-13) s s(-1) at 99 per cent confidence level. This is stronger than the value presented in Zane et al., but sufficiently similar that their scientific conclusions remain unchanged. We examine the implications in more detail, and find that RX J0720.4-3125 can have been born as a magnetar provided that it has a young age of similar to10(4) yr. A more conservative interpretation is that the field strength has remained relatively unchanged at just over 10(13) G, over the similar to10(6)-yr lifetime of the star
Bare quark stars or naked neutron stars? The case of RX J1856.5-3754
No full textIn a cool neutron star (T less than or similar to 10(6) K) endowed with a rather highmagnetic field (B greater than or similar to 10(13) G), a phase transition may occur in the outermost layers. As a consequence, the neutron star becomes "bare,'' i.e., no gaseous atmosphere sits on the top of the crust. The surface of a cooling, bare neutron star does not necessarily emit a blackbody spectrum because the emissivity is strongly suppressed at energies below the electron plasma frequency, omega(p). Since omega(p) approximate to 1 keV under the conditions typical of the dense electron gas in the condensate, the emission from a T similar to 100 eV bare neutron star will be substantially depressed with respect to that of a perfect Planckian radiator atmost energies. Here we present a detailed analysis of the emission properties of a bare neutron star. In particular, we derive the surface emissivity for an Fe composition in a range of magnetic fields and temperatures representative of cooling isolated neutron stars, like RX J1856.5 - 3754. We find that the emitted spectrum is strongly dependent on the electron conductivity in the solid surface layers. In the cold electron gas approximation ( no electron-lattice interactions), the spectrum turns out to be a featureless depressed blackbody in the 0.1 - 2 keV band with a steeper low-energy distribution. When damping effects due to collisions between electrons and the ion lattice ( mainly due to electron-phonon interactions) are accounted for, the spectrum is more depressed at low energies and spectral features may be present, depending on the magnetic field strength. Details of the emitted spectrum are found, however, to be strongly dependent on the assumed treatment of the transition from the external vacuum to the metallic surface. The implications of our results for RX J1856.5 - 3754 and other isolated neutron stars are discussed
In Memorium, Honorable Charles S. Zane
No full textIn Memorium, Honorable Charles S. Zane, born March 2, 1831, Chief Justice of Supreme Court of the Territory of Utah in 1884, Honorary Member of Alta Club in Salt Lake City, Utah, died March 29, 191
Título: Dissertationes, orationes, epistolae et carmina
No full textSign.: §\p4\s, A-Z\p4\s, 2A-2S\p4\sCada oración con portadilla propi
Social media activism e sostenibilità. Educare giovani attivisti digitali alla transizione ecologica
No full textIl progetto ‘Social, sostenibilità ambientale, Generazione Z’, frutto della collaborazione fra la cattedra di Pedagogia e formazione per la transizione ecologica dell’Università Cattolica del Sacro Cuore, l’Alta Scuola per l'Ambiente e Silea Spa vuole esplorare opinioni e sentire della Gen Z in ordine ai problemi della sostenibilità ambientale e della disponibilità ad agire mediante la comunicazione social. La Generazione Z interrogata attraverso la somministrazione di un questionario semi strutturato conferma come la sostenibilità sia un tema presente e rilevante sui social media, tuttavia, nonostante la letteratura evidenzi una massiccia esposizione dei giovani sui social, gli intervistati dichiarano di non voler compiere azioni di divulgazione in prima persona. Emerge che il protagonismo dei giovani deve essere cercato progettando azioni formative mirate, in grado di coinvolgerli attivamente come generazione che può contribuire alla buona riuscita della transizione ecologica.The project ‘Social, Environmental Sustainability, Generation Z’ a result of collaboration between
the Chair of Pedagogy and Training for Ecological Transition at the Catholic University of the Sacred
Heart, the High School for the Environment, and Silea Spa, aims to explore the opinions and
sentiments of Generation Z regarding environmental sustainability issues and their willingness to take
action through social communication. Generation Z, surveyed through the administration of a semistructured questionnaire, confirms that sustainability is a prevalent and relevant topic on social media.
However, despite literature indicating a massive youth presence on media, the interviewees declare their reluctance to engage in dissemination actions firsthand. It emerges that youth leadership must be sought by designing targeted training actions capable of actively involving them as a generation that can contribute to the success of the ecological
Thermal emission from isolated neutron stars and their surface magnetic field: Going quadrupolar?
No full textSocial media activism e sostenibilità. Educare giovani attivisti digitali alla transizione ecologica.
No full textIl progetto ‘Social, sostenibilità ambientale, Generazione Z’, frutto della collaborazione fra la cattedra di Pedagogia e formazione per la transizione ecologica dell’Università Cattolica del Sacro Cuore, l’Alta Scuola per l'Ambiente e Silea Spa vuole esplorare opinioni e sentire della Gen Z in ordine ai problemi della sostenibilità ambientale e della disponibilità ad agire mediante la comunicazione social. La Generazione Z interrogata attraverso la somministrazione di un questionario semi strutturato conferma come la sostenibilità sia un tema presente e rilevante sui social media, tuttavia, nonostante la letteratura evidenzi una massiccia esposizione dei giovani sui social, gli intervistati dichiarano di non voler compiere azioni di divulgazione in prima persona. Emerge che il protagonismo dei giovani deve essere cercato progettando azioni formative mirate, in grado di coinvolgerli attivamente come generazione che può contribuire alla buona riuscita della transizione ecologica
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