206 research outputs found
Professor Xavier Barcons Jauregui Director General European Southern Observatory
No full textVisit of Professor Xavier Barcons Jauregui Director General European Southern Observator
Baluards de supèrbia: reflexions crítiques sobre les agressions sexuals i la justícia en el pensament de Martha C. Nussbaum
No full textThe Chair of Legal Culture of the UdG organizes the II Catalan Interuniversity Seminar on Philosophy of Law. Maria Barcons, from the UAB, and Víctor Merino from the URV present their vision on the book "Baluards of Pride" by Martha C. Nussbaum, which denounces how masculine and structural power perpetuates sexual violence and harassment. The author calls for urgent legal and public reforms to combat these abuses, focusing on egalitarian human dignity and structural change instead of resentmentLa Càtedra de Cultura Jurídica de la UdG organitza el II Seminari interuniversitari català de filosofia del dret. Maria Barcons, de la UAB, i Víctor Merino de la URV exposen la seva visió sobre el llibre
Baluards de supèrbia" de Martha C. Nussbaum, on es denuncia com el poder masculí i estructural perpetua la violència sexual i l'assetjament. L'autora reclama reformes legals i públiques urgents per combatre aquests abusos, posant el focus en la dignitat humana igualitària i el canvi estructural en lloc del ressentiment5101
Testing the binary black hole paradigm through the Fe K alfha line profile : application to 3C 273
No full textWe propose the study of long-term variations in the Fe Ka line profile as a discriminator for binary black hole (BH) systems. The existence of a binary BH in the center of an active galaxy will produce a particular signature in the evolution of the line profile, as a result of disk precession. This signature is a periodic variation of the position of the blue edge of the profile, accompanied by periodic change of its intensity. We show that detection of the former is clearly within the observational capabilities of planned X-ray missions. Detecting a periodic variation of line profiles would provide the first direct evidence for precessing disks in active galactic nuclei, as opposed to the existing evidence supporting only the precession of jets. We apply these ideas to 3C 273.Fil: Torres, Diego F.. Lawrence Livermore National Laboratory; Estados UnidosFil: 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; ArgentinaFil: Barcons, Xavier. Instituto de física de cantabria; EspañaFil: Lu, Youjun. University of Toronto; Canad
Probing the Precession of the Inner Accretion Disk in Cygnus X-1
No full textWe show that changes in the orientation of the inner accretion disk of Cyg X-1 affect the shape of the broad Fe Ká emission line emitted from this object, in such a way that eV-level spectral resolution observations (such as those that will be carried out by the Astro-E2 satellite) can be used to analyze the dynamics of the disk. We present here a potential diagnostic tool supported by numerical simulations by which a few observations of Cyg X-1, separated in time, can determine whether its accretion disk actually precesses, and if so, determine its period and precession angle. This approach could also be used for similar studies in other microquasar systems.Fil: Torres, Diego F.. Lawrence Livermore National Laboratory; Estados UnidosFil: 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; ArgentinaFil: Barcons, Xavier. Instituto de Física de Cantabria; EspañaFil: Lu, Youjun. University of Science and Technology of China; Chin
"Otras ventanas de observación: el universo violento"
No full textComo complemento a la exposición "Sorpresas del Cosmos", se organizaron una serie de encuentros con el título genérico de "Enigmas del universo". En la imagen, plano general de Xavier Barcons, del Instituto de Física de Cantabria, durante la conferencia "Otras ventanas de observación: el universo violento
HARD X-RAY-EMISSION FROM EXTRAGALACTIC IRAS 12-MICRON SOURCES - CONSTRAINTS ON THE UNIFIED ACTIVE GALACTIC NUCLEUS MODEL AND THE SYNTHESIS OF THE X-RAY-BACKGROUND
No full textWe analyze the 2-10 keV X-ray emission of recently compiled complete samples of active galactic nuclei (AGNs) and galaxies selected at 12 mu m. The content in active galaxies of the 12 mu m sample is indeed much larger and less biased against low-luminosity and ''hidden'' active nuclei than samples selected at other wavelengths. As a necessary complement, we also study the IR emissivity of the largest sample of hard-X-ray-selected AGNs. Our purposes are to probe the unified scheme of active nuclei and to evaluate the local X-ray volume emissivity of low-luminosity and ''hidden'' AGNs. Two methods are used in our analysis to search for X-ray emission in the HEAO I A-2 all-sky maps from the extragalactic sources contained in the extended 12 mu m sample: an X-ray intensity distribution analysis around the known positions of the sources and a cross-correlation function analysis between galaxy densities and X-ray intensities in the high Galactic latitude sky (\b\ > 25 degrees), where the catalog is more than 98% complete. The joint analysis of the X-ray-selected and 12 mu m-selected samples enables us to define the relationship between the X-ray and the mid-IR emissions of Seyfert nuclei. In particular, we find congruence between the hard X-ray and mid-IR Seyfert 1 nuclear-luminosity functions when a nonlinear relation L(12 mu m) proportional to L(5 keV)(0.8) is with appropriate dispersion, Although this result is easily explained by circumnuclear reradiation as the main source of the mid-IR emission, it nonetheless argues against the simplest version of the unified model for active nuclei. We confirm that X-ray emission is basically restricted to AGNs, finding Seyfert 1's to be much more powerful emitters than Seyfert 2's. We find no signal of X-ray emission for the remaining galaxies selected at 12 mu m, not even for those having a flat far-IR spectrum, which are prime candidates to host hidden AGNs. Our result on the local volume emissivity of the Seyfert 1's is fully consistent with those that we derive from studies of the hard X-ray luminosity function, The 95% upper limits to the local emissivity that we derive for the Seyfert 2 class and for the most likely ''hidden'' AGN candidates are consistent with models of the X-ray background recently proposed based on the unified Seyfert scheme. We also find that less than similar to 20% of Seyfert 1-like AGNs and less than similar to 50% of Seyfert 2-like AGNs can be ''hidden'' in the non-Seyfert-galaxy samples, assuming that the X-ray-to-12 mu m flux ratios measured in the 12 mu m-selected samples can be considered typical for these classes of objects. In this case, the number ratio of Seyfert 2 to Seyfert 1 galaxies ranges from 1 to 2
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