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GABRIELA GONZALEZ: Gravity spy

A physicist helped to catch the first direct signs of long-sought gravitational waves.
By Davide Castelvecchi

A year ago, Gabriela Gonzalez was struggling to contain the biggest secret of her life. Two giant detectors in the United States had picked up signs of gravitational waves — wrinkles in space-time imagined by Albert Einstein but never before directly witnessed. It was Gonzalez’s job to help lead more than 1,000 scientists in their careful efforts to verify the discovery before announcing it to the public.

News like that doesn’t stay under wraps for long, but the discovery was so momentous that the research team took nearly five months to analyse data from the two Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors in Washington state and Louisiana. As spokesperson for the LIGO Scientific Collaboration, Gonzalez was one of the key people coordinating the analysis by groups scattered around the world, including researchers at the Virgo interferometer near Pisa, Italy, which pools its data with LIGO.

The role of shepherding this massive effort made use of Gonzalez’s multidimensional talents. Most physicists know early on whether they will be a theorist or an experimentalist. But Gonzalez started her graduate studies as a theoretical physicist and only later switched to experimental work, when she showed uncommon aptitude. “It was the thing that set her up as a first-class scientist,” says Rainer Weiss, a physicist at the Massachusetts Institute of Technology in Cambridge and one of the founders of LIGO.

Throughout her career, Gonzalez has done “a bit of everything” at LIGO, she says. For a while, she took on the crucial task of diagnosing the performance of the interferometers to make sure that they achieved unparalleled sensitivity — which is now enough to detect length changes in the 4-kilometre-long arms of the interferometers to within one part in 1021, roughly equivalent to the width of DNA compared with the orbit of Saturn. She has helped to lead the teams that analyse the data. And she nudged gravitational-wave researchers and dozens of their colleagues in conventional astronomy into signing pacts of cooperation. Together, they will look for phenomena that emit both gravitational and electromagnetic waves, in what has been called the coming age of multimessenger astronomy.

In the hectic months before announcing the LIGO discovery, Gonzalez and her colleagues struggled to make sure that they had iron-clad evidence. They knew that history had not been kind to those who had previously reported gravitational waves. Most recently, in early 2015, an international collaboration had to retract its claims that a tele­scope at the South Pole had discovered indirect signs of the long-sought vibrations.

To add to the pressure on the LIGO team, rumours of a discovery began to leak within a week of the initial finding, and reporters started to call. Throughout the long analysis period, Gonzalez says, she never made an important decision without consulting colleagues. But others laud her leadership. “What Gaby did is, she managed to get us through this period,” Weiss says.

Gonzalez is based at Louisiana State University in Baton Rouge, close to the LIGO interferometer in Livingston. In 2008, she became the first woman to receive a full professorship in her department. She says that she has never experienced outright sexual harassment or discrimination during her career, but “I had to prove myself perhaps more than other people”.

Gonzalez has said that after her current term as LIGO spokesperson ends in March 2017, she will not run again. She plans to go back to full-time research. The field of science she helped to create — gravitational-wave astronomy — has just seen its dawn. “It has always been a fun ride. And now it’s even better.”