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VIRGO

Virgo is a laser interferometer with two perpendicular, 3km-long arms: its purpose is detecting gravitational waves from astrophysical sources It is hosted at the European Gravitational Observatory, in the countryside near Pisa, in Italy.

Aerial view of EGO and Virgo

The detector is a Michelson interferometer, which can detect the minuscule length variations in its two 3 km (1.9 mi) arms induced by the passage of gravitational waves. The required precision is achieved using many systems to isolate it from the outside world, including keeping its mirrors and instrumentation in an ultra-high vacuum and suspending them using complex systems of pendula.

One of the 3 km long tunnels where the laser light travels

The Virgo Collaboration works together with the scientists of the LIGO Scientific Collaboration and of the KAGRA Collaboration to form the LIGO-Virgo-KAGRA (LVK) Collaboration. The LVK Collaboration is a network of scientists who coordinate and collaborate on the operation of the detectors and on the production of the scientific results.

Activities in Bologna


The Virgo group in Bologna is formed by several colleagues from the  “Dipartimento di Fisica e Astronomia ‘Augusto Righi’ of Alma Mater Studiorum – Università di Bologna” (DIFA), and the “Istituto Nazionale di Fisica Nucleare – Sezione di Bologna” (INFN-Bo) and joined the Virgo collaboration in February 2025.
The scientific and technological interests are distributed over various research fields and cover all the main Virgo activities as follows.

Data Analysis

The principal interests relate to the exploitation of gravitational waves (GW) as cosmological probes, to the search for transient signals (long and short) and to multi-messenger astrophysics. Moreover, we plan to contribute through the development of pipelines for the analysis of simulated GWs and multi-messenger data, including the study and implementation of innovative pipelines based on the Machine Learning approach. The activity of the group will be inserted in CBC analysis with the contribution of new waveform. The activity involves searching for evidence of area discretization in CBC (compact binary coalescence) data. Starting with waveforms predicted by General Relativity (GR), the aim is to calculate effects suggested by area quantization. This involves using a specific metric developed by India and INFN-Bologna colleagues, which incorporates a fundamental length scale into spacetime. The goal is to estimate a new waveform that includes these effects. This modified waveform would then be applied to the data to determine whether standard GR is sufficient within the error margins or if there are hints that these quantization effects are needed.
The burst analysis will focus on two main areas: improving and refining the WDF burst pipeline for all-sky short signal searches and applying it to search for CCSN signals. Additionally, a machine learning stage will be incorporated into the WDF pipeline to analyze coincidences across three detectors.

Computing

The main interest is the development of FPGA-based electronic boards and the relative firmware development, to implement low-latency workflows and parallel algorithms design, real-time/online DAQ and data processing, time synchronization with the White Rabbit technology for very accurate timing and clock stability, software and computing techniques including Artificial Intelligence workflows and the design of data and computing models. We will collaborate also with CNAF center for the implementation of GW search and multimessenger search pipelines

Operations

Detector Characterization Members with great expertise of Virgo data analysis for detector noise studies can contribute to the analysis of Virgo noise and to the testing on new pipelines for classification noise transient signals. The study and put in production of ML-based solution for glitch identification will be part of the activity of the DIFA-INFN group, with the target of helping noise hunting group.

Detector

  • Coating: exploratory studies on materials such as oxides to serve also as R&D activities for Virgo next.
  • Electronics: Members of the group are already involved in the study and production of electronic boards for SAT in collaboration with other groups of Virgo collaboration.

Commissioning (ENV)

The DIFA geophysics group has a decadal experience in theoretical modeling and processing of seismic and environmental noise. Their applications have spanned soil characterization and lithospheric imaging, joint inversion of deformation and seismic responses, and detection and understanding of very low-frequency environmental and deep-Earth processes. Its core research is equally focused on modeling and experiments, providing ideal constraints to noise reduction and detector characterization. We will contribute to further site characterization through expertise in seismicity and seismic noise, stability of slopes and landslides, in situ stress studies, high-precision vertical displacements determinations on the basis of new generation gravimetry, deformation models.

Education and Training

Through DIFA Bachelor, Master, PhD courses (with more than 130 students enrolled every year) and the INFN unit and INAF contribution to DIFA PhD, will also play a unique role in providing the education and training ground where students and young scientists will acquire expertise within the Virgo collaboration.

People

 

Member Role Main  Institution Virgo Role Interests
Elena Cuoco Full Professor DIFA Group Leader

Data analysis: Burst analysis, Machine Learning, detector characterization

Riccardo Travaglini Senior technologist INFN-BO INFN-BO local representative Electronics: Mirror Position Control

Gabriele Balbi

 Technologist INFN-BO    Electronics: Mirror Position Control

Alessandro Pesci

 Senior Researcher INFN-BO   
Data analysis: CBC

Nicola Borghi 

 Research Fellow DIFA  
Data analysis: Cosmology

Matteo Tagliazucchi

 PhD Student DIFA  
Data analysis: Cosmology

Maurizio Spurio

 Full Professor DIFA  
Data Analysis: Multimessenger physics. External coincidences

Annarita Margiotta

 Associate professor DIFA  
Data Analysis: Multimessenger physics. External coincidences

Beatrice Fraboni

 Full Professor DIFA  
Detector: Coating techniques

Sara Cepic

 PhD Student DIFA  
Detector: Coating techniques

Luca Pasquini

 Full Professor DIFA  
Detector: Coating techniques

Daniele Bonacorsi

 Full Professor DIFA  
Low latency. Low latency system architecture

Luca De Siena

 Associate professor DIFA  

Detector characterization “Monitoring known or new DQ issues” Commissioning/ENV

Enrico Paolucci 

 Junior assistant professor DIFA  

Detector characterization “Monitoring known or new DQ issues” Commissioning/ENV

Enrico Gianfranco Campari

 Associate Professor DIFA  

Detector: Coating techniques

Simone Dall’Osso

   INAF  

 

Antonio Ghinassi

 Undergraduated student DIFA  

Data analysis: Machine Learning

Maria Giuliana Stratta

 Researcher INAF  

 

Giovanni Mastropasqua

 Technician INFN-BO  

Electronics: Mirror Position Control

Pictures

Members of the Bologna group visiting Virgo