CV and full scientific publication list (pdf).

Most of my scientific papers are available on ArXiv and/or ADS.

Google Scholar citations.

ORCID iD iconorcid.org/0000-0002-3929-6932

Scopus Author ID: 56227420000


Research activity

I am a theoretical astrophysicist and my research is mostly focused on comparing models and simulations with astronomical data, in order to advance our knowledge of the workings of the universe.

Currently, my main research interest is in astrobiology, the interdisciplinary study of the origin, evolution, distribution and future of life in the universe. I am working on models of planetary and galactic habitability, and on the search for biosignatures and technosignatures.

In the past I have done work in many areas of physical cosmology, including the analysis of the cosmic microwave background anisotropy, the large-scale structure of the universe, inflation, dark matter and dark energy.

Below is an annotated list (in rough inverse chronological order) of some of my past and present research projects.


Research projects

Supermassive black holes and planetary habitability

There is a huge black hole at the center of the Milky Way, and at the beginning of its history it went through an active phase, which released large amounts of ionizing radiation in space. This might have had large-scale consequences on the habitability of planets in the galaxy, affecting their atmospheres and possibly their surface biosphere. This is one of the first studies on the subject, which I will explore further in ongoing work. (For press coverage of this study, see here, here, here and here)

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Modeling the spatiotemporal distribution of observers in the universe

The discovery of thousands of exoplanets has given new impulse to the search of technological species in the universe, whose presence we might infer through remote astronomical observations. With this goal in mind, it is crucial to produce realistic predictions of the number and distribution of such species, both in space and time. I started by producing a two-parameter temporal model that expands and complement the standard approach based on the Drake equation. More to come.

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Real time cosmology

The idea, originally proposed by Allan Sandage in the 1960s, is that one can observe the evolution of cosmological redshift in time, by means of ultra-high precision spectroscopy. This can give interesting information on cosmological models as well as on the dynamics of bound objects. I explored the implications of the idea in a number of papers and summarized them in a review.

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Gravitational lensing of the cosmic microwave background

Observing the effect of gravitational lensing of the cosmic microwave background produced by matter distribution in the universe can give important cosmological information. I explored this issue in the following papers.

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Violations of isotropy

CMB data from the WMAP satellite showed hints of possibile anomalies in the statistical isotropy of temperature fluctuations, one of the tenets of standard cosmology. This can be due to instrumental effects or to physical mechanisms. I investigated the issue in a number of papers.

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Non-gaussianity of primordial perturbations

Inflationary models predict that density perturbations in the early universe have a non-gaussian statistics. Measuring the amount of non-gaussianity can constrain theoretical models. I investigated the issue through the analysis of CMB data.

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Dark energy and integrated Sachs-Wolfe effect

One of the ways of studing dark energy is through the imprint that the onset of the accelerating phase of the universe leaves on the CMB. This is called integrated Sachs-Wolfe effect, and can be observed by cross-correlating the CMB with large-scale structure data.  I authored (with my then student Davide Pietrobon) one of the first studies finding evidences of this signal in the data, using a new statistical technique (courtesy of Domenico Marinucci).

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Unified models of dark matter and dark energy

According to some theoretical models, dark matter and dark energy may be the same thing under different form. Our analyses showed that this might be the case, but observations available at the time could not tell the difference from alternative explanations.

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Dark energy and quintessence

One of the possible explanations of dark energy is that it is caused by the presence of a fundamental field called “quintessence”. The advantage of these models is that they may alleviate the so-called “coincidence problem”, that is the weird fact that the vacuum energy density have begun to dominate with respect to the density of matter roughly at present time.

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Planck

Planck was an ESA space mission designed to observe the CMB to unprecedented details. I started collaborating to Planck in 1996 (when it was still in the study phase) and continued until 2012, with the intermediate data release, contributing to many of the procedures that were used to analyze its data, and to extract its scientific consequences.

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BOOMERANG

I briefly collaborated to the second phase of the BOOMERANG balloon experiment, that studied the polarized component of the cosmic microwave background.

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MAXIMA

MAXIMA was a balloon-borne experiment that produced, in 2000, one of the first high-resolution images of the cosmic microwave background temperature fluctuations. MAXIMA results put precise constraints on cosmological models, showing that we live in a universe with flat geometry.  I gave a relevant contribution to all of MAXIMA scientific results and data analysis, and I was the first author of the cosmological parameter paper. Here is MAXIMA official press release with a summary of results. Other non-technical information can be found here and here and in articles that appeared on Physics Today and Scientific American. MAXIMA results also got strong coverage in the press, with articles on The San Francisco ChronicleThe EconomistThe New York TimesThe Washington Post and again The New York Times. The PBS show NOVA discussed MAXIMA in one of its episodes.

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Cosmic microwave background data analysis

Extracting cosmological information from CMB data is challenging and computing-intensive. Some of my research activity was devoted to finding new algorithms, statistical techniques and tools to maximize the scientific output of observations.

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Thermal history of the universe

The universe went through different physical phases, as its temperature changed from the big bang to the present epoch due to the expansion of space. Some of the pivotal moments in the history of the cosmos (such as the synthesis of light nuclei, or the formation of neutral hydrogen atoms, or of the ignition of the first stars) can be explored through cosmological observations. I addressed the study of the thermal history of the universe in some of my earliest scientific papers.

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