Research

RESEARCH HIGHLIGHTS

My research centers around observational cosmology, with particular interest in distant galaxies, cosmic heavy-element enrichment, and galaxies hosting gamma-ray bursts (GRBs).

    • In 2006, I wrote a review article for the New Journal of Physics on GRBs as probes of the chemical enrichment history to z = 6. In 2012, I published a paper as lead author on the finding of over-solar metallicity in the interstellar medium of a z ∼ 3.57 galaxy hosting GRB 090323.
    • I created a public database, called GRB Host Studies (GHostS), containing information of the properties of GRB host galaxies. GHostS is also the largest and most complete database of its kind (as of August 2015, 233 objects). It has been used so far for the publication of 33 peer-reviewed articles (2007-2015). GHostS uses the Virtual Observatory resources.
    • In 2009, I published, as a lead author, an article about the largest sample of GRB host galaxies. According to the Science Citation Index definition, this is a high impact article.
    • I discovered the redshift evolution of the mass-metallicity relation in field galaxies, according to which the metal enrichment scales with the stellar mass of galaxies. These findings support an early formation of massive galaxies, not easily accounted for by most theoretical models.
    • I am regularly invited to meetings, and public events (on TV/radio, in schools). I contribute with articles and interviews for the popularization of astrophysics. In 2004, I featured an article (and cover) of the Time magazine, about the massive migration of European scientists to North American’s institutes and universities.
    • In the past, I have investigated QSO absorption lines as probes of the intergalactic medium and high redshift galaxies. I led the analysis effort of the Hubble Space Telescope STIS spectra towards the QSO as part of the Hubble Deep Field South campaign.

Gemini Deep Deep Survey

Together with my collaborators of the GDDS team, I discovered the redshift evolution of the mass-metallicity relation in galaxies, according to which the metal enrichment scales with the stellar mass of galaxies. These findings support an early formation of massive galaxies, not easily accounted for by most theoretical models. Our team has found many interesting results, some of which regard the assembly of massive galaxies in the universe, and were published in Nature.

OTHER SCIENTIFIC INTERESTS

Studying the average speed as a function of the race time in running and swimming world records, I found that the point distributions can be reproduced by two well-defined scaling laws. This discovery was published together with Vincenzo Carbone (University of Calabria) in Nature (Savaglio & Carbone 2000). In short races, the average speed declines sharply with increasing performance time (or distance), for long races the decline is more gentle. The time of change of slope (about two and a half minutes) marks the transition between the anaerobic and aerobic energy expenditure by athletes, and is universal for men and women, for swimmers and runners. I also investigated the forecasting of athletics world records using historical data. The results, based on the identification of non-Poissonian events for a sequence of temporal point processes, show that the improvements in all records from 1900 to the present day cannot be considered completely random and that, at least from a purely mathematical point of view, forecasting is possible. The data distribution show evident periodicity related to cyclical training or cyclical top level competitions, as well as to social phenomena on large scales.

 

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