CV

Research activity

Accretion, Pulsar timing and ULX.

Much of my research involves the study of accreting X sources, typically neutron stars or black holes. Although I also study these objects from a spectroscopic and/or aperiodic timing point of view, I am often involved in work that needs pulsar timing, because of my experience in this type of analysis and the software I have written and run (see below). I am recognized as one of the key names in the study of Ultraluminous X-ray sources (ULX; as evidenced by the many invited talks to speak on the subject). In particular, I contributed to the first XMM+NuSTAR campaign of ULX observations, publishing the first solid evidence of a spectral break above 10 keV, and in 2014 I discovered the first ultraluminous pulsar in M82 X-2, and still coordinate its follow-up (and recently, measured its orbital decay). I have several collaborations in place for these studies in Italy and many other countries, notably the USA, France, UK, Spain and the Netherlands (see network plot at the end of this section). Recently, I coordinated the HEX-P ULX working group, that made a feasibility study for ULX science with the NASA Probe mission concept HEX-P.

Spectral timing (/polarimetry).

Together with Daniela Huppenkothen and others, I have written and continuously maintain one of the leading spectral timing analysis software for high-energy data, Stingray. This analysis is a link between traditional spectral and temporal analysis, and is considered one of the keys to unhinging many of the uncertainties about accretion on compact objects. We coordinate the work and gather input from many contributors at all career levels, from young Google Summer of Code students to experienced researchers and developers. With Daniela Huppenkothen, I recently wrote a review on this topic, as a chapter in the book on temporal analysis (eds. T. Belloni, D. Bhattacharya) of the Handbook of X-ray and Gamma-ray Astrophysics, edited by Cosimo Bambi. I was the national PI of the PRIN TEC INAF 2019-Spectempolar, and with expert spectral timing assignee Guglielmo Mastroserio we optimized Stingray for use with future and present ultra-high throughput instruments such as eXTP and NICER, and added polarimetric information from instruments such as the gas pixel detectors of IXPE and eXTP. With Eleonora Veronica Lai, we are further optimizing the code for use in parallel architecture, as part of Spoke 3 of the PNRR-funding National Centre for HPC, Big Data and Quantum Computing project.

Development and calibration of observational instruments.

I am on the Science Team and/or calibration/operational teams of several ongoing space missions (IXPE, NuSTAR) and the Sardinia Radio Telescope. One of my most important jobs in this regard was the coordination of the time calibration of the NuSTAR satellite, which began immediately after launch in 2012 and was completed during my visit as a Fulbright Scholar at Caltech in 2019. Our work has improved by two orders of magnitude the accuracy in correcting the arrival times of photons to the satellite, making NuSTAR suitable, for example, for studying millisecond pulsars. This work, which even in its early stages helped the discovery of pulsars in M82 X-2, earned me a NASA Medal for Exceptional Scientific Achievement in 2016. For NuSTAR, I contributed to the last two Senior Reviews, both of which were favorably evaluated by NASA with mission continuation. For the IXPE mission, I wrote much of the automatic reduction pipeline of ground test data. I am part of the IACHEC (International astronomical consortium for high-energy calibration) consortium as a timing representative for the NuSTAR mission, and I coordinate the work of comparing the timing performance of all space missions using observations of Crab and other pulsars, as a member of the Timing WG. For the Sardinia Radio Telescope I am on the operations team and manage and develop the single dish imaging code used to teach these techniques in the Radio Astronomy Laboratory course and for quicklook data during observations. Over the years I have contributed to the science working groups (WGs) of many mission proposals. In particular, I am co-I of proposals for new missions (most recently the HEX-P probe) and WP leader for the GECO ground segment. I am the national PI of an INAF Curiosity Techno project on the development of new perovskite-based X-ray detectors.

Statistics, new algorithms, citizen science.

I pursue various innovative algorithm development projects, either to overcome systematic instrumental effects or barriers due to prohibitive computational costs, or in an attempt to overcome inherent limitations in the accuracy of traditional data analysis methods. Some examples: new analysis algorithms and machine learning and simulation based inference for modeling dead time and correlation between different components of variability (with Daniela Huppenkothen); the development of 3D computer games for pulsar search with citizen science (I am scientific PI of the CICLOPS project with the company Infora, see figure); the adaptation of statistics traditionally used in high-energy astrophysics to classify pulsar candidates (the $Z_n^2$ or the $H$-test) to data at all wavelengths

Publication record

Source: NASA ADS, UT 2026-10-11. Citations and h-index refer to the refereed papers.

217 papers in refereed journals (12 as first author)
Book Chapters: 1
White papers: 6
Refereed Conference proceedings: 12
Proceedings and online presentations: 31
Astronomer’s Telegrams: 22
Internal reports: 9
34636 citations from 22504 papers
1299 citations to my first-author papers, from 1048 papers
h-index: 60

ORCID · NASA ADS

Work Experience

Jan. 2024-today: Senior researcher, INAF-Osservatorio Astronomico di Cagliari. Spectral timing studies of compact objects
Dec. 2016-2023: Staff scientist (permanent), INAF-Osservatorio Astronomico di Cagliari. Spectral timing studies of compact objects
Dec. 2015-2016: Staff scientist, INAF-Osservatorio Astronomico di Cagliari. Multiwavelength studies from radio to X-rays of compact Galactic sources
Sept. 2014-Nov. 2015: Post Doc Researcher, Osservatorio Astronomico di Cagliari. Multiwavelength studies of double neutron star binaries and X-ray binaries
Feb. 2010-Aug. 2014: CNES Post Doctoral Fellowship and short contracts, IRAP (formerly CESR), Toulouse, France. Accretion studies with NuSTAR; development of the LOFT and SVOM missions; noise modelling in Planck-HFI; search for QPOs in the RXTE archive

Education

12 Feb 2010: PhD, Università degli Studi di Cagliari. Thesis: Numerical Methods for the study of rapid X-ray variability in low-mass X-ray binaries. Supervisor: Luciano Burderi; co-supervisor Tiziana di Salvo. Mark: Ottimo (Outstanding). ISCED level 8
23 Nov 2006: Laurea Specialistica (Master’s Degree), Università degli Studi di Cagliari. Thesis: Sviluppo di codici per la ricerca di pulsar binarie (Development of codes for binary pulsar search). Supervisor: Luciano Burderi; co-supervisor Andrea Possenti, Marta Burgay. Mark: 110/110 cum laude. ISCED level 7
12 Nov 2003: Laurea Triennale (Bachelor’s Degree), Università degli Studi di Cagliari. Thesis: Ricerca di pulsar in sistemi binari: il problema della conferma dei candidati (Search of pulsars in binary systems: the problem of candidate confirmation). Supervisor: Nichi D’Amico; co-supervisor Andrea Possenti, Marta Burgay. Mark: 110/110 cum laude. ISCED level 6