En Español Welcome to the Lazzati Group page
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The Lazzati Group performs research in theoretical astrophysics. Current research focuses on understanding the physics of Gamma-Ray Bursts and of Cosmic Dust.
Research News
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A new, more modern version of this site is under construction. During construction, this site will not be updated. We anticipate to publish the new site by the end of 2017. Thanks for your patience.
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Feb 2015: Time dependent Comptonization in GRB prompt emission
Time dependent MonteCarlo calculations by Atul Chhotray show the role of time dependent effects in the observed spectrum of the prompt emission of Gamma-Ray Bursts in the photospheric model. -
Jan 2015: Structure and ground states of carbon clusters
Ab-initio calculations by Chris Mauney provide the ground configuration and cohesive energies of all carbon clusters with up to 99 carbon atoms. These results will be extremely helpful in the calculation of the nucleation rate of carbonaceous dust. -
May 2014: Golenetskii correlation from photospheric GRBs
Simulations performed by the Oregon State GRB group in collaboration with the University of Wisconsin at Madison show that the prompt emission of simulated gamma-ray bursts within the photospheric scenario can reproduce the Golenetskii correlation. -
December 2013: Move to Oregon
The Lazzati astrophysics research group has relocated to Oregon State University.
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June 2013: The GRB engine duration
Simulations performed by the NCSU GRB group in collaboration with the University of Colorado show that a fairly standard GRB engine duration of 20 seconds can reproduce the observed BATSE duration distribution. -
May 2013: Supernova Conference
The astrophysics group at NC State is organizing a conference on the progenitors, mechanism, and consequences of stellar explosions. The conference will take place in the Physics Department of NCSU between May 13 and May 17, 2013. More informations can be found here. -
Feb 2013: 3D simulations of GRB jets
The NCSU GRB group presents the first 3D GRB jet simulations performed with an adaptive mesh code. arXiv -
Jan 2013: The Amati correlation explained
Numerical simulations performed by the NCSU GRB group showed that the elusive Amati correlation can be reproduced by photospheric emission from hydrodynamic jets. The same simulations reproduced other correlations bolstering the hypothesis that the bulk of the prompt GRB radiation comes from the jet's photosphere. arXiv -
July 2012: NSF CAREER Award
Dr. Lazzati is awarded a NSF CAREER grant to perform research on the properties and structure of cosmic dust particles. The research will include the use of Density Functional Theory techniques to compute the properties of grains to big to be called molecules, yet too small to be identified as solids. NSF website -
May 2012: photospheric emission in GRBs becomes popular
Nature runs a short news article on the results presented at the Munich GRB conference emphasizing the change of paradigm in the modeling and interpretation of GRB prompt emission spectra. Nature News -
March 2012: Jet-Driven Stellar explosions
A study of the NCSU GRB group reveals the important role of the engine duration in the outcome of relativistic jet-driven supernovae. For a fixed explosion energy, short engines produce ordinary looking SNe, intermediate engines produce relativistic SNe and/or weak GRBs, and long engines produce successful GRBs. arXiv -
August 2011: Nature commentary
A News and Views commentary by Prof. Lazzati on the Swift discovery of the tidal disruption of a star by a supermassive black hole appears in Nature. Full article (subscription needed) -
June 2011: carbon dust in SNe
A parametric study of the NCSU Dust Formation Group reveals the consequences of different microphysical properties on the yields of carbonaceous dust formation in type II supernovae. arXiv -
March 2011: Prompt GRB conference
The NCSU Physics department hosted the conference "The prompt activity of gamma-ray bursts: their progenitors, engines, and radiation mechanisms" from March 4 until March 7, 2011. More than 70 international experts participated to the conference. See the program and download the presentations at the conference website. -
March 2011: off-axis photospheres
Numerical simulations performed and analyzed by the NCSU GRB group reveal that the photospheric emission of GRB jets depends on the viewing geometry. Off-axis photospheres are more efficient than on-axis photospheres and their emission qualitatively reproduces the observed correlation between burst energy and typical photon frequency (the so-called Amati correlation). arXiv -
August 2010: X-ray Flares
Numerical simulations performed and analyzed by the NCSU GRB group reveal the origin of the afterglow's X-ray flares. It is found that the feedback of the progenitor star on the relativistic jet triggers luminosity fluctuations with temporal characteristics analogous to the observed flares. arXiv -
June 2010: Dust Nucleation
The role of thermal fluctuations and nanoscale dimensions in the nucleation of dust is explored. A higher nucleation rate ensues. arXiv -
May 2010: Non-thermal spectra from GRB photospheres
The NCSU GRB group studies a new mechanism to explain the spectra of the prompt emission of long-duration GRBs. arXiv -
Feb 2010: GRB Variability pattern
The NCSU GRB group succesfully reproduces the GRB variability pattern with a set of high-resolution simulations of GRB jets and their propagation inside the progenitor star. arXiv -
Nov 2009: Short duration GRBs from collapsar
The NCSU GRB group suggests that a subclass of the short-duration GRB population may originate from collapsar explosions seen at wide angles. If confirmed by observations, this prediction would be a paradigm shift, breaking the old view according to which long GRBs are associated to massive stars and short GRBs are associated to compact object mergers. arXiv -
Jan 2010: NCSU 3D GRB jet in Nature movie
A 3D animation of GRB explosion by NCSU GRB group featured on Nature video. See full film on the Nature Website
