Prospects for multi-messenger extended emission from core-collapse supernovae in the Local Universe

Multi-messenger emissions from SN1987A and GW170817/GRB170817A suggest a Universe rife with multi-messenger transients associated with black holes and neutron stars. For LIGO-Virgo, soon to be joined by KAGRA, these observations promise unprecedented opportunities to probe the central engines of core-collapse supernovae (CC-SNe) and gamma-ray bursts. Compared to neutron stars, central engines powered by black hole-disk or torus systems may be of particular interest to multi-messenger observations by the relatively large energy reservoir $E_J$ of angular momentum, up to 29\% of total mass in the Kerr metric. These central engines are expected from relatively massive stellar progenitors and compact binary coalescence involving a neutron star. We review prospects of multi-messenger emission by catalytic conversion of $E_J$ by a non-axisymmetric disk or torus. Observational support for this radiation process is found in a recent identification of ${\cal E}\simeq (3.5\pm1)\%M_\odot c^2$ in Extended Emission to GW170817 at a significance of 4.2\,$\sigma$ concurrent with GRB170817A. A prospect on similar emissions from nearby CC-SNe justifies the need for all-sky blind searches of long duration bursts by heterogeneous computing.Comment: 96 pages, 20 figure

Hard x-ray broad band Laue lenses (80 - 600 keV): building methods and performances

We present the status of the laue project devoted to develop a technology for building a 20 meter long focal length Laue lens for hard x-/soft gamma-ray astronomy (80 - 600 keV). The Laue lens is composed of bent crystals of Gallium Arsenide (GaAs, 220) and Germanium (Ge, 111), and, for the first time, the focusing property of bent crystals has been exploited for this field of applications. We show the preliminary results concerning the adhesive employed to fix the crystal tiles over the lens support, the positioning accuracy obtained and possible further improvements. The Laue lens petal that will be completed in a few months has a pass band of 80 - 300 keV and is a fraction of an entire Laue lens capable of focusing X-rays up to 600 keV, possibly extendable down to 20 - 30 keV with suitable low absorption crystal materials and focal length. The final goal is to develop a focusing optics that can improve the sensitivity over current telescopes in this energy band by 2 orders of magnitude

Laue Lens Development for Hard X-rays (>60 keV)

Results of reflectivity measurements of mosaic crystal samples of Cu (111) are reported. These tests were performed in the context of a feasibility study of a hard X-ray focusing telescope for space astronomy with energy passband from 60 to 600 keV. The technique envisaged is that of using mosaic crystals in transmission configuration that diffract X-rays for Bragg diffraction (Laue lens). The Laue lens assumed has a spherical shape with focal length $f$. It is made of flat mosaic crystal tiles suitably positioned in the lens. The samples were grown and worked for this project at the Institute Laue-Langevin (ILL) in Grenoble (France), while the reflectivity tests were performed at the X-ray facility of the Physics Department of the University of Ferrara.Comment: 6 pages, 12 figures, accepted for publication in IEEE Transactions on Nuclear Scienc

Neuquén, una anti-ciudad

La racionalidad técnica moderna ha desplazado hasta anular la posibilidad de otros modos de habitar el espacio urbano. Se hace un recorrido histórico de los modos de habitar en comunidad (Antigüedad, Edad Media, Modernidad, actualidad) y un análisis particularizado de la fundación y desarrollo de la ciudad argentina de Neuquén, en el marco general de las ciudades modernas. Se plantea la vida en las denominadas anticiudades como esencialmente marcada por la técnica provocante en oposición a la tekhné poiética griega. Asimismo en el ámbito comunitario se opone la ciudad orgánica de las comunidades antiguas o no occidentales con la ciudad fragmentada moderna. De ambas dimensiones se extraen consecuencias políticas y ontológicas. El hilo general es la dimensión de la Comunicación.Facultad de Periodismo y Comunicación Socia

Neuquén, una anti-ciudad

La racionalidad técnica moderna ha desplazado hasta anular la posibilidad de otros modos de habitar el espacio urbano. Se hace un recorrido histórico de los modos de habitar en comunidad (Antigüedad, Edad Media, Modernidad, actualidad) y un análisis particularizado de la fundación y desarrollo de la ciudad argentina de Neuquén, en el marco general de las ciudades modernas. Se plantea la vida en las denominadas anticiudades como esencialmente marcada por la técnica provocante en oposición a la tekhné poiética griega. Asimismo en el ámbito comunitario se opone la ciudad orgánica de las comunidades antiguas o no occidentales con la ciudad fragmentada moderna. De ambas dimensiones se extraen consecuencias políticas y ontológicas. El hilo general es la dimensión de la Comunicación.Facultad de Periodismo y Comunicación Socia

Intrinsic spectra and energetics of BeppoSAX Gamma-Ray Bursts with known redshifts

We present the main results of a study of spectral and energetics properties of twelve gamma-ray bursts (GRBs) with redshift estimates. All GRBs in our sample were detected by BeppoSAX in a broad energy range (2-700 keV). From the redshift estimates and the good-quality BeppoSAX time-integrated spectra we deduce the main properties of GRBs in their cosmological rest frames. All spectra in our sample are satisfactorily represented by the Band model with no significant soft X-ray excesses or spectral absorptions. We find a positive correlation between the estimated total (isotropic) energies in the 1-10000 keV energy range (E_rad) and redshifts z. Interestingly, more luminous GRBs are characterized also by larger peak energies E_p of their EF(E) spectra. Furthermore, more distant GRBs appear to be systematically harder in the X-ray band compared to GRBs with lower redshifts. We discuss how selection and data truncation effects could bias our results and give possible explanations for the correlations that we found.Comment: 10 pages, 5 figures, accepted for publication in Astronomy & Astrophysic

Home i natura: els usos tradicionals del sòl i la pesca

Cabrera, lloc de pas de les antigues rutes marítimes de la mediterrània occidental, illa en els límits de l'habitable, ha estat escassament poblada. La naturalesa, d'una banda, i els condicionants socials i històrics, de l'altra, s'han aliat per allunyar la societat. Així i tot, l'home ha utilitzat els recursos naturals de l'Arxipèlag. Les activitats ramadera, agrícola, forestal i pesquera es repeteixen al llarg de la història amb intensitat variable. D'altra banda, l'ús militar i, més modernament, el turístic, també han tingut repercussions sobre el paisatge. En aquest article feim un breu repàs de les activitats tradicionals de l'home a Cabrera, analitzant-les des de la perspectiva històrica.The harsh nature and social and historic constraints have made Cabrera be nearly always very scantly populated during all its history. The antique merchant ship routes have made use of the port of Cabrera, and the natural resources of the island have always been exploited (farming, livestock raising and fishing). In more recent times Cabrera has been used military and now days the most important usage of the archipelago is tourism. We discuss the traditional activities of man on Cabrera with a historical perspective

Swift XRT Observations of the Breaking X-ray Afterglow of GRB 050318

We report the results of Swift X-Ray Telescope (XRT) observations of GRB 050318. This event triggered the Burst Alert Telescope (BAT) aboard Swift and was followed-up with XRT and UVOT for 11 consecutive orbits starting from 54 minutes after the trigger. A previously unknown fading X-ray source was detected and accurately monitored. The source was found to decrease in intensity with time and a clear temporal break occurring at ~18000 s after the trigger was observed. The X-ray light curve was found to be consistent with a broken power-law with decay indices -1.17 +/- 0.08 and -2.10 (+0.22) (-0.24) before and after the break. The spectrum of the X-ray afterglow was well described by a photoelectrically absorbed power-law with energy index of -1.09 +/-0.09. No evidence of spectral evolution was found. We compare these results with those obtained with UVOT and separately reported and refine the data analysis of BAT. We discuss our results in the framework of a collimated fireball model and a synchrotron radiation emission mechanism. Assuming the GRB redshift derived from the farthest optical absorption complex (z = 1.44), the event is fully consistent with the E_p-E_iso correlation.Comment: Accepted for publication in A&A Letters (5 pages, 3 figures