Calendar

Short duration gamma-ray bursts (GRBs) are widely thought to result from compact binaries mergers. Growing observational evidence seems to support this popular scenario. At the same time Swift observations of short GRBs revealed new features on their emission properties: precursors, X-ray flares and, in particular, a temporally extended emission provide compelling evidence of a long-lived central engine. The traditional neutron stars merger model does not naturally account for such late time activity. I will present the current observational status of short GRBs and discuss the implications, with particular regard to progenitors population.

Very low-mass stars and brown dwarfs are fully convective, a reason to expect that the solar-like dynamo does not work. Implications for the pattern of magnetic activity are expected. Putting X-ray emission in context with activity signatures in other wavebands (optical and radio) allows to understand the changes — if any — of the coronal heating mechanism across the fully convective boundary and the hydrogen burning mass limit. Young brown dwarfs, moreover, possess circumstellar disks from which they accrete matter. Considering them substellar analogs to T Tauri stars, accretion shocks represent potential sites of X-ray emission next to the coronal plasma. I discuss recent X-ray observations of two brown dwarfs in the context described above: DENIS 1048-39, a very low-mass field star observed in the past to be a radio burst source, and FU Tau A, the primary of an isolated young brown dwarf binary.

A short summary of the recent activities related to SphinX instrument repository, data reduction and analysis will be discussed. Possible directions of scientific research of SphinX measurement will be shown. Examples of new results will be given.

The remnant of SN1006 is well known to be the archetypical cosmic-ray accelerating supernova remnant, with two bright limbs dominated by non-thermal emission. In the soft X-ray band the emission is dominated by a thermal component which was traditionally associated to the shocked stellar ejecta fragments. In this talk, we will present the results obtained with the XMM-Newton Large Project on this remnant about this component. In particular, we will address the longstanding issue of the lack of apparent X-ray emission from the shocked ISM, which may provide evidence for proton acceleration through the observation of CR back-reaction effects, and a comprehensive study of the X-ray emitting ejecta, which will give us for the first time a direct evidence for an asymmmetric SN Type Ia explosion.

Mixed-morphology SNRs are characterized by a shell-like radio emission and a centrally peaked X-ray morphology and are all interacting with molecular clouds. Many models have been proposed to explain these peculiar remnants, but their physical origin is still unclear. The recent discovery of overionized (i. e. recombining) ejecta in 3 MM SNRs has dramatically challenged all the previous models and opened up new, unexpected scenarios. I review the main properties of these remnants and present an XMM-Newton observation of W49B together with a hydrodynamic model developed to explain the new results. I also discuss the (long) list of open questions.

The thermal structure of the post-shock region of a young supernova remnant (SNR) is heavily affected by two main physical effects, namely the back-reaction of accelerated cosmic rays and the Rayleigh-Taylor instabilities developing at the contact discontinuity between the ejecta and the shocked interstellar medium (ISM). In this contribution, we investigate the role played by both physical mechanisms in the evolution of SNRs through detailed MHD modeling.We present a three-dimensional MHD model which describes the expansion of the remnant through a magnetized ISM, including consistently for the first time the initial ejecta clumping and the effects on shock dynamics due to back-reaction of accelerated cosmic rays.

We will present a working prototype of YouASTRO (www.youastro.org), a web-based BibTeX-compliant reference management software (RMS) for astrophysical papers in the SAO/NASA ADS database. It also includes as a main feature the concept of distributed paper comments and ratings. Community-based reviews and comments, and more in general participatory information sharing, have proven to be a very effective way to spread the knowledge in many fields, and they are the focus of Web 2.0 applications. In this demo, we will show how to create and manage a BibTeX personal library to use for citations in our own articles and how to share comments on ADS papers. We will briefly discuss what could be the advantages and drawbacks of such a system being widespread adopted by the astrophysical community for its scientific literature.

This talk will present the results of recent high resolution studies of the nuclear regions of active galaxies with Chandra. With these data we are setting observational constraints on the parameters of AGN feedback, which is considered a main agent in galaxy evolution. I will also report the very recent discovery of a close double supermassive black hole in one of these galaxies.

As part of the ESA Cosmic Vision program a “Large” mission concept for imaging X-ray Astromomy is currently in phase A study. The mission, nicknamed ATHENA, result from a very fast and aggressive few month long redefinition phase started April 2011 and ending by October 2011 with a selection for possible phase B (definition) study on February 2012. I will briefly discuss the motivation behind and the rationale for this redefinition process, its outcome, the capability of the newly designed Athena space observatory and the major scientific questions this mission will allow to address. I will also briefly present my view on the overall scenario of the ESA science program and the pros e con of the Athena fitting in this evolving scenario and related advancement of European astrophysics.

MENU`
Antipasto: Anagrafica siciliana alla occidentale
Primo: Risotto di ONC in fotometria NIR
Secondo: Interazione stella-pianeta in salsa magnetica
Contorno: Flambe` di esopianeti
Frutta: Macedonia GAIA affogata in liquore RVS
Dolce: Buffet di possibili collaborazioni:
Studio delle SED delle pre-MS VLMS in Orione Analisi degli spettri RIz di candidati BD in Orione NGC2264 – Campagna osservativa 14-25 Marzo 2008
Chef: Gaetano Scandariato