Gravitational waves from a binary black hole merger observed by LIGO and Virgo

RIO GRANDE VALLEY, TEXAS – SEPT. 27, 2017 – The LIGO Scientific Collaboration and the Virgo collaboration today announced the first joint detection of gravitational waves with both the LIGO and Virgo detectors.

This is the fourth announced detection of a binary black hole system, and the first significant gravitational-wave signal recorded by the Virgo detector, and highlights the scientific potential of a three-detector network of gravitational-wave detectors.

Physicists at The University of Texas Rio Grande Valley’s Center for Gravitational Wave Astronomy (CGWA) are credited with contributions to the series of gravitational wave discoveries. 

CGWA is housed at UTRGV and has been a member of the LIGO Scientific Collaboration since 1998. It is funded in part with grants from the National Aeronautic Space Administration and the National Science Foundation.

Dr. Mario Díaz, director of CGWA, said this discovery is yet another milestone in the history of gravitational wave astronomy.

“In the future, the shrinking of the probable area of localization of a gravitational wave source will it make easier for astronomers to find an electromagnetic counterpart, if that exists,” he said. 

The three-detector observation occurred at 10:30:43 UTC on Aug. 14, 2017. The two Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors, located in Livingston, Louisiana, and Hanford, Washington, and funded by the National Science Foundation, and the Virgo detector, located near Pisa, Italy, detected a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes.

A paper about the event, known as GW170814, has been accepted for publication in the Physical Review Letters journal.

The detected gravitational waves – ripples in space and time – were emitted during the final moments of the merger of two black holes with masses about 31 and 25 times the mass of the sun and located about 1.8 billion light-years away.

The newly produced spinning black hole has about 53 times the mass of our sun, which means that about three solar masses were converted into gravitational-wave energy during the coalescence.

“Little more than a year and a half ago, NSF announced that its Laser Gravitational Wave Observatory had made the first-ever detection of gravitational waves resulting from the collision of two black holes in a galaxy a billion light-years away,” said France Córdova, NSF director. “Today, we are delighted to announce the first discovery made in partnership between the Virgo Gravitational-Wave Observatory and the LIGO Scientific Collaboration – the first time a gravitational-wave detection was observed by these observatories, located thousands of miles apart.

“This is an exciting milestone in the growing international scientific effort to unlock the extraordinary mysteries of our universe,” Córdova said.

The Virgo detector joined the LIGO second observational run, O2, on Aug. 1, 2017, at 10:00 UTC. The real-time detection on Aug. 14 was triggered with data from all three LIGO and Virgo instruments. Virgo is, at present, less sensitive than LIGO, but two independent search algorithms based on all the information available from the three detectors demonstrated the evidence of a signal in the Virgo data, as well.

The CGWA has the largest group of gravitational-wave researchers in Texas, and one of the largest in the United States, involved in the LIGO Scientific Collaboration global research effort. Its scientists and student researchers are key contributors to the first direct detection of gravitational waves. 

UTRGV scientists and students have been involved for almost 20 years in the development of core technologies and instrumentation used by the LIGO detectors, installation and commissioning of hardware for the detectors at the Hanford and Livingston sites, modeling of noise sources that can contaminate the data, development of new algorithms that analyze the data in search of gravitational-wave signals, and follow-up searches with optical telescopes that try to catch the optical counterpart of these events.

Coauthors of the Physical Review Letters paper mentioned above are CGWA and UTRGV faculty members Teviet Creighton, Mario Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov and Joseph Romano; and graduate students Karla Ramirez, Robert Stone, Darkhan Tuyenbayev, Wenhui Wang and former graduate student Dr. Guillermo Valdes, now a Louisiana State University scientist working at the at the LIGO Laboratory in Livingston.

Quetschke chairs the Lasers and Auxiliary Optics working group of the LIGO Scientific Collaboration, guiding the research toward laser systems for the next generation interferometric gravitational wave detectors. He and his group work toward high-power, fiber-based laser systems for future cryogenic GW detectors.

Rakhmanov conducts research in optical resonators and trains students in the techniques of experimental gravitational-wave physics. He has been with LIGO since 1994.

Mukherjee's research group investigates various aspects to improve gravitational wave detection from core collapse supernovae.

Romano and Creighton work in different aspects of gravitational wave data analysis.

Díaz more recently has been the doctoral dissertation supervisor for Valdes, who just graduated with a PhD in Physics and now is a scientist at the LIGO Livingston Laboratory. Diaz also is the supervisor of doctoral student Karla Ramirez, who is currently a LIGO Scientific Collaboration fellow at the LIGO Livingston Laboratory. Additionally, he leads a group in astronomy searching for optical counterparts of gravitational waves, and is director of the UTRGV Astronomical Observatory located in Resaca de la Palma State Park.

LIGO is funded by NSF and operated by Caltech and MIT, which conceived and built the project. Financial support for the Advanced LIGO project was led by NSF with Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council) and Australia (Australian Research Council) making significant commitments and contributions to the project.

More than 1,200 scientists from around the world, including those at UTRGV, participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration.

Additional partners are listed at

The Virgo collaboration consists of more than 280 physicists and engineers belonging to 20 different European research groups: six from Centre National de la Recherche Scientifique (CNRS) in France; eight from the Istituto Nazionale di Fisica Nucleare (INFN) in Italy; two in The Netherlands with Nikhef; the MTA Wigner RCP in Hungary; the POLGRAW group in Poland; Spain with the University of Valencia; and EGO, the laboratory hosting the Virgo detector near Pisa in Italy.

The University of Texas Rio Grande Valley (UTRGV) was created by the Texas Legislature in 2013 as the first major public university of the 21st century in Texas. This transformative initiative provided the opportunity to expand educational opportunities in the Rio Grande Valley, including a new School of Medicine, and made it possible for residents of the region to benefit from the Permanent University Fund – a public endowment contributing support to the University of Texas System and other institutions.

UTRGV has campuses and off-campus research and teaching sites throughout the Rio Grande Valley including in Boca Chica Beach, Brownsville (formerly The University of Texas at Brownsville campus), Edinburg (formerly The University of Texas-Pan American campus), Harlingen, McAllen, Port Isabel, Rio Grande City, and South Padre Island. UTRGV, a comprehensive academic institution, enrolled its first class in the fall of 2015, and the School of Medicine welcomed its first class in the summer of 2016.

UTRGV Director of News and Internal Communications / 956-665-2742