628 citations · 8.3k across the 153 of their papers we have counts for
14 papers · 1 filter
Time-Dependent Photoionization in a Dusty Medium. III: The effect of dust on the photoionization of metals
Davide Lazzati, Rosalba Perna
We use the time-dependent photoionization and dust destruction code developed by Perna & Lazzati (2002) to study the time evolution of the medium in a dusty gaseous cloud illuminat…
Time-Dependent Photoionization in a Dusty Medium II: Evolution of Dust Distributions and Optical Opacities
Rosalba Perna, Davide Lazzati, Fabrizio Fiore
The interaction of a radiation field with a dusty medium is a relevant issue in several astrophysical contexts. We use the time-dependent photoionization code in a dusty medium dev…
The Brera Multi-scale Wavelet ROSAT HRI source catalogue (BMW-HRI)
M. R. Panzera, S. Campana, S. Covino +4
We present the Brera Multi-scale Wavelet ROSAT HRI source catalogue (BMW-HRI) derived from all ROSAT HRI pointed observations with exposure time longer than 100 s available in the…
X-ray lines, progenitor and beaming of Gamma-Ray Bursts
Davide Lazzati
X-ray emission features have been detected in at least five GRB afterglows. Their detection and properties are of great importance in our understanding of the nature of the GRB pro…
Polarization curves of GRB afterglows predicted by the universal jet structure
E. Rossi, D. Lazzati, J. D. Salmonson +1
It has been recently proposed that current burst and afterglow observations can be accounted for by a top hat jet structure as well as by a more universal structured outflow, in wh…
Internal Shocks and the Blazar Sequence
D. Guetta, G. Ghisellini, D. Lazzati +1
We consider the internal shock model as the dissipation mechanism responsible for the emission in blazars. It has been shown that this model is successful in reproducing the observ…
The afterglow of GRB 021004: surfing on density waves
D. Lazzati, E. Rossi, S. Covino +2
We present a model for the early optical afterglow of GRB 021004. This burst had one of the earliest detected optical afterglows, allowing a dense optical sampling. The lightcurve…
Thermal components in the early X-ray afterglow of GRBs
Davide Lazzati
The possible presence of thermal components in the early X-ray afterglows of gamma-ray bursts is investigated. We discuss both the presence of a thermal continuum and, in particula…
Time-Dependent Photoionization in a Dusty Medium I: Code Description and General Results
Rosalba Perna, Davide Lazzati
We present a time-dependent photoionization code that combines self-consistently metal evolution and dust destruction under an intense X-ray UV radiation field. Firstly, we extend…
The role of photon scattering in shaping the lightcurves and spectra of gamma-ray bursts
Davide Lazzati
We analyze the power spectra of the lightcurves of long gamma-ray bursts, dividing the sample in bins of luminosity, using the recently discovered variability-luminosity correlatio…
Emission lines in GRBs constrain the total energy reservoir
G. Ghisellini, D. Lazzati, E. M. Rossi +1
The emission features observed in the X-ray afterglow of Gamma Ray Bursts are extremely powerful. Since they last at least for several hours, they imply energies of the order of 1e…
Soft X-ray emission lines in the early afterglow of gamma-ray bursts
Davide Lazzati, Enrico Ramirez-Ruiz, Martin J. Rees
We compute the luminosity of K_alpha emission lines produced by astrophysically abundant elements in the soft X-ray spectra of the early afterglow of gamma-ray bursts. We find that…
Hard X-ray afterglows of short GRBs
Davide Lazzati, Enrico Ramirez-Ruiz, Gabriele Ghisellini
We report the discovery of a transient and fading hard X-ray emission in the BATSE lightcurves of a sample of short gamma-ray bursts. We have summed each of the four channel BATSE…
X-ray spectroscopy of gamma-ray bursts: the path to the progenitor
Davide Lazzati, Rosalba Perna, Gabriele Ghisellini
Despite great observational and theoretical effort, the burst progenitor is still a mysterious object. It is generally accepted that one of the best ways to unveil its nature is th…