Search results for " Astronomia"

Negative and positive feedback from a supernova remnant with SHREC

2022

Supernova remnants (SNRs) contribute to regulate the star formation efficiency and evolution of galaxies. As they expand into the interstellar medium (ISM), they transfer vast amounts of energy and momentum that displace, compress and heat the surrounding material. Despite the extensive work in galaxy evolution models, it remains to be observationally validated to what extent the molecular ISM is affected by the interaction with SNRs. We use the first results of the ESO-ARO Public Spectroscopic Survey SHREC, to investigate the shock interaction between the SNR IC443 and the nearby molecular clump G. We use high sensitivity SiO(2-1) and H$^{13}$CO$^+$(1-0) maps obtained by SHREC together wit…

Modeling the mixed-morphology supernova remnant IC 443. Origin of its complex morphology and X-ray emission

2020

The morphology and the distribution of material observed in SNRs reflect the interaction of the SN blast wave with the ambient environment, the physical processes associated with the SN explosion and the internal structure of the progenitor star. IC 443 is a MM SNR located in a quite complex environment: it interacts with a molecular cloud in the NW and SE areas and with an atomic cloud in the NE. In this work we aim at investigating the origin of the complex morphology and multi-thermal X-ray emission observed in SNR IC 443, through the study of the effect of the inhomogeneous ambient medium in shaping its observed structure, and the exploration of the main parameters characterizing the re…

Observatori Astronòmic

2008

Els misteris del cel estan més prop des de la fundació, fa ja un segle, de l'Observatori Astronòmic de la Universitat de València. Actualment, l'Observatori viu una etapa d'expansió. El seu personal desenvolupa diverses línies d'investigació, i al mateix temps realitza tasques de docència i divulgació de l'astronomia en la societat.

The THESEUS space mission concept: science case, design and expected performances

2018

THESEUS is a space mission concept aimed at exploiting Gamma-Ray Bursts for investigating the early Universe and at providing a substantial advancement of multi-messenger and time-domain astrophysics. These goals will be achieved through a unique combination of instruments allowing GRB and X-ray transient detection over a broad field of view (more than 1sr) with 0.5¿1 arcmin localization, an energy band extending from several MeV down to 0.3¿keV and high sensitivity to transient sources in the soft X-ray domain, as well as on-board prompt (few minutes) follow-up with a 0.7¿m class IR telescope with both imaging and spectroscopic capabilities. THESEUS will be perfectly suited for addressing …

Spectral analysis and orbital evolution of Low Mass X-ray Binaries at high inclination

X-Ray binaries are gravitationally bound systems consisting of a compact object that accretes matter from a companion star; they are the most interesting objects of the sky, infact they allow to study the physics of matter in very extreme conditions of density, temperature or magnetic eld. So the determination of spectral and temporal properties of X-ray binaries plays an important role in understanding the processes involved in these systems. This project aims to understand the properties of binary systems, at high inclination (dipping and eclips- ing sources), containing neutron stars weakly magnetized. In the light curves of these systems it is possible to identify a variety of modulatio…

Multimessenger search for sources of gravitational waves and high-energy neutrinos: Initial results for LIGO-Virgo and IceCube

2014

Made available in DSpace on 2022-04-29T07:21:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-11-17 We report the results of a multimessenger search for coincident signals from the LIGO and Virgo gravitational-wave observatories and the partially completed IceCube high-energy neutrino detector, including periods of joint operation between 2007-2010. These include parts of the 2005-2007 run and the 2009-2010 run for LIGO-Virgo, and IceCube's observation periods with 22, 59 and 79 strings. We find no significant coincident events, and use the search results to derive upper limits on the rate of joint sources for a range of source emission parameters. For the optimistic assumption of …

Linking Small-scale Solar Wind Properties with Large-scale Coronal Source Regions through Joint Parker Solar Probe–Metis/Solar Orbiter Observations

2022

Abstract The solar wind measured in situ by Parker Solar Probe in the very inner heliosphere is studied in combination with the remote-sensing observation of the coronal source region provided by the METIS coronagraph aboard Solar Orbiter. The coronal outflows observed near the ecliptic by Metis on 2021 January 17 at 16:30 UT, between 3.5 and 6.3 R ⊙ above the eastern solar limb, can be associated with the streams sampled by PSP at 0.11 and 0.26 au from the Sun, in two time intervals almost 5 days apart. The two plasma flows come from two distinct source regions, characterized by different magnetic field polarity and intensity at the coronal base. It follows that both the global and local p…

Accretion disk coronae of intermediate polar cataclysmic variables

2017

Context. Intermediate polar cataclysmic variables (IPCV) contain a magnetic, rotating white dwarf surrounded by a magnetically truncated accretion disk. To explain their strong flickering X-ray emission, accretion has been successfully taken into account. Nevertheless, observations suggest that accretion phenomena might not be the only process behind it. An intense flaring activity occurring on the surface of the disk may generate a corona, contribute to the thermal X-ray emission, and influence the system stability. Aims. Our purposes are: investigating the formation of an extended corona above the accretion disk, due to an intense flaring activity occurring on the disk surface; studying t…

High Performance Computing on the COMETA Grid Infrastructure

2008

We present the High Performance Computing (HPC) projects jointly developed at the INAF - Osservatorio Astronomico di Palermo and at the DSFA - Universita` di Palermo which benefits of the Grid infrastructure of COMETA. We have contributed to setup the infrastructure in order to run HPC applications on the Grid. We report on our experience regarding to porting HPC applications to the Grid and to the first HPC simulations performed. The most demanding simulations describe the interaction of a magnetized supernova shock wave with an interstellar gas cloud. We discuss the resources required for the simulations, the performance and the scalability of our code on the Grid, and present first resul…

Active shape correction of a thin glass/plastic x-ray mirror

2015

Optics for future X-ray telescopes will be characterized by very large aperture and focal length, and will be made of lightweight materials like glass or plastic in order to keep the total mass within acceptable limits. Optics based on thin slumped glass foils are currently in use in the NuSTAR telescope and are being developed at various institutes like INAF/OAB, aiming at improving the angular resolution to a few arcsec HEW. Another possibility would be the use of thin plastic foils, being developed at SAO and the Palermo University. Even if relevant progresses in the achieved angular resolution were recently made, a viable possibility to further improve the mirror figure would be the app…