SN/GRB connection: a statistical approach with BATSE and Asiago Catalogues

Recent observations suggest that some types of GRB are physically connected with SNe of type Ib/c. However, it has been pointed out by several authors that some GRBs could be associated also with other types of core-collapse SNe (type IIdw/IIn). On the basis of a comphrensive statistical study, which has made use of the BATSE and Asiago catalogues, we have found that: i) the temporal and spacial distribution of SNe-Ib/c is marginally correlated with that of the BATSE GRBs; ii) we do not confirm the existence of an association between GRBs and SNe-IIdw/IIn.Comment: Proceeding of the 4th workshop on Gamma Ray Bursts in the Afterglow Era, Rome, 2004; 4 page

Mining the XRT archive to probe the X-ray absorber structure in the AGN population

One of the key ingredients of the Unified Model of Active Galactic Nuclei (AGN) is the presence of a torus-like optically thick medium composed by dust and gas around the putative supermassive black hole. However, the structure, size and composition of this circumnuclear medium are still matter of debate. To this end, the search for column density variations through X-ray monitoring on different timescales (months, weeks and few days) is fundamental to constrain size, kinematics and location of the X-ray absorber(s). Here we describe our project of mining the Swift-XRT archive to assemble a sample of AGN with extreme column density variability and determining the physical properties of the X-ray absorber(s). We also present the results obtained from a daily-weekly Swift-XRT follow-up monitoring recently performed on one of the most interesting new candidates for variability discovered so far, Mrk 915.Comment: 6 pages, 3 figures. To appear in Proceedings of Science for the "Swift: 10 years of Discovery" meeting, held in Rome (2-5 December 2014

The structure of the X-ray absorber in Mrk 915 revealed by Swift

In this paper we present the results obtained with a monitoring programme (23 days long) performed with Swift-XRT on the local Seyfert galaxy Mrk 915. The light-curve analysis shows a significant count rate variation (about a factor of 2-3) on a time-scale of a few days, while the X-ray colours show a change in the spectral curvature below 2 keV and the presence of two main spectral states. From the spectral analysis we find that the observed variations can be explained by the change of the intrinsic nuclear power (about a factor of 1.5) coupled with a change of the properties of an ionized absorber. The quality of the data prevents us from firmly establishing if the spectral variation is due to a change in the ionization state and/or in the covering factor of the absorbing medium. The latter scenario would imply a clumpy structure of the ionized medium. By combining the information provided by the light curve and the spectral analyses, we can derive some constraints on the location of the absorber under the hypotheses of either homogeneous or clumpy medium. In both cases, we find that the absorber should be located inside the outer edge of an extended torus and, in particular, under the clumpy hypothesis, it should be located near, or just outside, to the broad emission line region.Comment: 8 pages, 6 figures, 1 table. Accepted for publication on MNRA

Low-loss amorphous silicon waveguides grown by PECVD on indium tin oxide

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XMM-Newton and NuSTAR joint observations of Mrk 915: a deep look into the X-ray properties

We report on the X-ray monitoring programme (covering slightly more than 11 days) carried out jointly by XMM-Newton and NuSTAR on the intermediate Seyfert galaxy Mrk 915. The light curves extracted in different energy ranges show a variation in intensity but not a significant change in spectral shape. The X-ray spectra reveal the presence of a two-phase warm absorber: a fully covering mildly ionized structure [log xi/(erg cm/s)~2.3, NH~1.3x10^21 cm-2] and a partial covering (~90 per cent) lower ionized one [log xi/(erg cm/s)~0.6, NH~2x10^22 cm-2]. A reflection component from distant matter is also present. Finally, a high-column density (NH~1.5x10^23 cm-2) distribution of neutral matter covering a small fraction of the central region is observed, almost constant, in all observations. Main driver of the variations observed between the datasets is a decrease in the intrinsic emission by a factor of ~1.5. Slight variations in the partial covering ionized absorber are detected, while the data are consistent with no variation of the total covering absorber. The most likely interpretation of the present data locates this complex absorber closer to the central source than the narrow line region, possibly in the broad line region, in the innermost part of the torus, or in between. The neutral obscurer may either be part of this same stratified structure or associated with the walls of the torus, grazed by (and partially intercepting) the line of sight.Comment: 14 pages, 10 figures, 4 tables. Accepted for publication in MNRA

Antiproton modulation in the Heliosphere and AMS-02 antiproton over proton ratio prediction

We implemented a quasi time-dependent 2D stochastic model of solar modulation describing the transport of cosmic rays (CR) in the heliosphere. Our code can modulate the Local Interstellar Spectrum (LIS) of a generic charged particle (light cosmic ions and electrons), calculating the spectrum at 1AU. Several measurements of CR antiparticles have been performed. Here we focused our attention on the CR antiproton component and the antiproton over proton ratio. We show that our model, using the same heliospheric parameters for both particles, fit the observed anti-p/p ratio. We show a good agreement with BESS-97 and PAMELA data and make a prediction for the AMS-02 experiment

Le spectromètre de masse à temps de vol DEPIL et son utilisation pour la mesure de masses de protéines élevées dépassant 5 000 u : insuline et lyzozyme

Un spectromètre de masse à temps de vol a été construit à l'Institut de Physique Nucléaire d'Orsay pour mesurer des masses de molécules diverses. La gamme de masses accessibles est comprise entre 1 et 20 000 u. Nous présentons ici une description succincte de l'appareillage avec des exemples de mesures de hautes masses