Papers by Vincenzo Antonuccio-Delogu
Universe
Theoretical predictions as well as experiments performed at storage rings have shown that the lif... more Theoretical predictions as well as experiments performed at storage rings have shown that the lifetimes of β-radionuclides can change significantly as a function of the ionization state. In this paper we describe an innovative approach, based on the use of a compact plasma trap to emulate selected stellar-like conditions. It has been proposed within the PANDORA project (Plasmas for Astrophysics, Nuclear Decay Observation and Radiation for Archaeometry) with the aim to measure, for the first time in plasma, nuclear β-decay rates of radionuclides involved in nuclear-astrophysics processes. To achieve this task, a compact magnetic plasma trap has been designed to reach the needed plasma densities, temperatures, and charge-states distributions. A multi-diagnostic setup will monitor, on-line, the plasma parameters, which will be correlated with the decay rate of the radionuclides. The latter will be measured through the detection of the γ-rays emitted by the excited daughter nuclei follo...
We discuss the problems arising when one tries to create a software interface between a parallel ... more We discuss the problems arising when one tries to create a software interface between a parallel treecode (modelling the collisionless, Dark Matter component) and Adaptive Mesh Refinement (AMR) hydrodynamical schemes (which model the gaseous phases). Such an interface would allow one to perform Nbody/Hydro simulations in those situations where the N-body and hydrodynamical codes are loosely coupled, and the gravitational influence of the dissipative, gaseous component on the DM component can be neglected. We discuss similarities and differences between the treeand AMR hydrocode data structures, restricting ourselves to two particular examples which are widely used in these days: the oct-tree Barnes-Hut and the cartesian structured grid AMR schemes. Finally, we present a simple scheme for such a software interface which we are beginning to use in cosmological simulations.
We present recent Hubble Space Telescope observations of the inner filament of Centaurus A, using... more We present recent Hubble Space Telescope observations of the inner filament of Centaurus A, using the new Wide Field Camera 3 (WFC3) F225W, F657N and F814W filters. We find a young stellar population near the southwest tip of the filament. Combining the WFC3 dataset with archival Advanced Camera for Surveys (ACS) F606W observations, we are able to constrain the ages of these stars to ∼ <10 Myrs, with best-fit ages of 1-4 Myrs. No further recent star-formation is found along the filament. Based on the location and age of this stellar population, and the fact that there is no radio lobe or jet activity near the star-formation, we propose an updated explanation for the origin of the inner filament. Sutherland et al. suggested that radio jet-induced shocks can drive the observed optical line emission. We argue that such shocks can naturally arise due to a weak cocoon-driven bow shock (rather than from the radio jet directly), propagating through the diffuse interstellar medium from a location near the inner northern radio lobe. The shock can overrun a molecular cloud, triggering star-formation in the dense molecular cores. Ablation and shock heating of the diffuse gas then gives rise to the observed optical line and X-ray emission. Deeper X-ray observations should show more diffuse emission along the filament.
The Astrophysical Journal
We reconsider the problem of the age of the stellar discs of late-type Low Surface Brightness (LS... more We reconsider the problem of the age of the stellar discs of late-type Low Surface Brightness (LSB) galaxies by making use of a new IMF recently derived from numerical fluid dynamical simulations (Padoan, Nordlund and Jones, 1997). While a Miller-Scalo IMF cannot adequately describe the photometric properties of LSBs, when we apply the new Padoan et al. (1997) IMF to
Arxiv preprint astro-ph/ …, 1999
Using the results of a high mass resolution (256 3 particles) N-body simulation of a cluster-form... more Using the results of a high mass resolution (256 3 particles) N-body simulation of a cluster-forming region, we study the statistic σ v − M for low mass halos (M < 10 12 M ⊙ ), and we compare it with three theoretical models. At the final redshift halos are well described by the Truncated Isothermal Sphere model recently introduced by Shapiro, . We speculate that this is a consequence of the action of tidal fields on galaxy formation within clusters.
On May 27th 2010, the Italian astronomical community learned with concern that the National Insti... more On May 27th 2010, the Italian astronomical community learned with concern that the National Institute for Astrophysics (INAF) was going to be suppressed, and that its employees were going to be transferred to the National Research Council (CNR). It was not clear if this applied to ...
On May 27th 2010, the Italian astronomical community learned with concern that the National Insti... more On May 27th 2010, the Italian astronomical community learned with concern that the National Institute for Astrophysics (INAF) was going to be suppressed, and that its employees were going to be transferred to the National Research Council (CNR). It was not clear if this applied to ...
AIP Conference Proceedings, 1997
The UBVRI colors of LSB discs seem to indicate that these galaxies are older than 7 Gyr, and thei... more The UBVRI colors of LSB discs seem to indicate that these galaxies are older than 7 Gyr, and their that mean age is probably about 9 Gyr.
We derive the conditional probability distribution f pk (v j ) of the peculiar velocity around a ... more We derive the conditional probability distribution f pk (v j ) of the peculiar velocity around a peak of given overdensity in a Gaussian density eld. This distribution characterizes the shear eld around local, isolated density peaks. We use the moments of the velocity distribution to study the spatial distribution of the escape velocity from protostructures forming in a standard, at, scale{invariant CDM model. In the case of high peaks with ltering scales R f 2h 1 Mpc, we nd that at distances between 2 4 Mpc h 1 (or equivalently 1 2 R f ) a sensitive fraction of the matter enclosed within an extrapolated (up to the present epoch) volume containing a total gravitating mass M 2:725 10 15 h 1 M (of the same order as that derived from gravitational lensing observations, see Tyson and Fisher 1995) is gravitationally unbound to the peak. The fraction of unbound matter varies between approximately between 0:05 0:2 depending on the central height of the density peak, on the ltering radius and on the adopted normalization for the uctuation spectrum. We show how these results support our previous conclusions regarding the delay of the collapse induced by the presence of small-scale substructure in clusters of galaxies formed in standard CDM cosmological models.
Monthly Notices of the Royal Astronomical Society, 1993
... Reidel, Dordrecht, in press Soderblom DR, 1985, AJ, 90,2103 Soderb!om DR, Duncan DK, Johnson ... more ... Reidel, Dordrecht, in press Soderblom DR, 1985, AJ, 90,2103 Soderb!om DR, Duncan DK, Johnson DRH, 1991, ApJ, 375, 722 Sommer-Larsen J., 1991a, MNRAS, 249, 368 Sommer-Larsen J., 1991b, MNRAS, 250, 356 Sommer-Larsen J., Christensen PR, 1989, MNRAS, 239 ...
Nuclear Physics B - Proceedings Supplements, 2004
Astronomical & Astrophysical Transactions, 1998
Lecture Notes in Computer Science, 1999
1 Astrophysical Observatory of Catania, Citt`a Universitaria, Viale A. Doria 6, I-95125 Catania, ... more 1 Astrophysical Observatory of Catania, Citt`a Universitaria, Viale A. Doria 6, I-95125 Catania, ITALY [email protected],[email protected] 2 Istituto di Astronomia, Universit`a di Catania, Citt`a Universitaria, Viale A. Doria 6, I-95125 Catania, ITALY ...
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Papers by Vincenzo Antonuccio-Delogu