LIGO & VIRGO announce a third gravitational-wave detection!
The LIGO Scientific Collaboration and the VIRGO Collaboration are proud to jointly-announce the detection of a third gravitational-wave event: GW170104, yet another coalescence of two stellar-mass black holes. The observation, which was made on the 4th of January 2017 by the two LIGO detectors, required months of careful analysis by the two collaborations to be confirmed.
In the photo, the newly-elected LIGO (David Shoemaker, left) and VIRGO (Jo van den Brand, right) spokespersons are celebrating the third detection GW170104 before joining the press briefing from the EGO Direction conference room.
The third detection paper is available here - Supplementary material is available here.
The third detection press release is available in English - French - Italian - Dutch - Polish - Spanish.
First detection of gravitational waves
On the 14th of September 2015, a gravitational wave was detected for the first ever time. This first detection was announced to the world on the 11th of February 2016:
What is Virgo?
Virgo is an interferometric gravitational-wave antenna. It consists of two 3-kilometre-long arms, which house the various machinery required to form a laser interferometer.
A beam-splitter divides a laser beam into two equal components, which are subsequently sent into the two interferometer arms. In each arm, a two-mirror Fabry-Perot resonant cavity extends the optical length from 3 kilometres to approximately 100. This is because of multiple reflections that occur within each cavity and which consequently amplify the tiny distance variation caused by a gravitational wave.
The two beams of laser light that return from the two arms are recombined out of phase so that, in principle, no light reaches the so-called 'dark fringe' of the detector. Any variation caused by an alteration in the distance between the mirrors, produces a very small shift in phase between the beams and, thus, a variation of the intensity of the light, which is proportional to the wave's amplitude.
Click here for more information on the Virgo experiment and its science.
The Virgo Collaboration
Virgo is a gravitational-wave interformeter designed, built and operated by a collaboration made up of 20 laboratories in 6 countries and involves the following institutions:
Interesting events are always being prepared at EGO-Virgo. Please view our Outreach website for details on up and coming, as well as recent, events.
Virgo and LIGO
Virgo and the LIGO Scientific Community work together in many areas and have a specific agreement on the exchange of data. More information on the work of our LIGO colleagues is available here.
More information on the identification and follow up of electromagnetic counterparts of gravitational wave candidate events is available here.
The Virgo-EGO Scientific Forum
Virgo and EGO have also established a scientific forum - the VESF - for astrophysicists and theorists, dedicated specifically to the furthering of scientific knowledge related to Virgo. More information is available here.
ET - Einstein Telescope
The Einstein Telescope (ET) project is dedicated to the development of a critical research infrastructure for a third-generation gravitational-wave interferometer. More information about the project, which is supported by the European Commission as part of the Framework Programme 7, is available here.
Other gravitational-wave experiments
Have a look at some of the other gravitational wave experiments:
Other gravitational-wave-related websites
Jobs & Fellowships
The following Virgo roles are currently being advertised:
Further roles at EGO are advertised on the EGO website.
If you are looking for information on an up-coming or recent event, please visit our Outreach website.
The Reception at the EGO site is open at the following times:
- Monday to Friday, from 08:30 to 13:00 and 14:00 to 17:30
- Closed on Saturdays and Sundays (except when site visits are scheduled)
How to get to Virgo
Virgo is at the site of the European Gravitational Observatory (EGO), the organisation responsible for the site, and is located in:
56021 Santo Stefano a Macerata – Cascina (Pisa), Italy.
As Virgo is located in the countryside, it is not particularly easy to access without a car, as there are no public transport links directly to it.
Arriving by car
The EGO-Virgo site GPS coordinates (in DD) are:
- Latitude: 43.6305 N
- Longitude: 10.5021
Arriving by plane/train and taxi
The nearest airport to Virgo is Pisa Galileo Galilei International Airport.
If you are travelling by aeroplane and arrive at the Pisa Galileo Galilei International Airport, or by train and arrive at Pisa Central train station, we recommend that you call a taxi (Co.Ta.Pi Radiotaxi Pisa, +39 050 54 16 00) complete your journey to EGO-Virgo.
It takes about 20-30 minutes to reach the site coming from Pisa when coming by car. The taxi fare from Pisa to the EGO-Virgo site costs about €35-40.
What do on arrival at the EGO-Virgo site
All visitors must present themselves at the site-entrance gate, where they will be met by their EGO contact person.
Visitors' vehicles may be parked at the site, in the appropriate parking areas.
New Virgo collaborators
New Virgo collaborators must complete the association and safety procedures before starting any activity on site. To this end, they should contact the EGO Administration (Building 4, first floor, +39 050 752 522/325) and the Safety and Security Office (Building 1, +39 050 752 416/544).
Badges to access the site and an account to access the Virgo documentation will only be granted by the IT department on completion of this process.