University of Wisconsin-Madison

Aya Ishihara wins Saruhashi Prize

Aya Ishihara at the South Pole in January, 2010. Image by Jim Haugen, IceCube/NSF.
Aya Ishihara at the South Pole in January, 2010. Image by Jim Haugen, IceCube/NSF.

Aya Ishihara, an IceCube collaborator and an associate professor of physics at Chiba University in Japan, has been awarded the 37th annual Saruhashi Prize, given each year to a female researcher in the natural sciences. This award recognizes women scientists under 50 for exceptional research accomplishments and for mentoring of other women scientists.

“I am very pleased to receive this Saruhashi award, which I have known since I was just a high school student,” explains Aya. “One of the important goals of this award is to let young girls know there are active female scientists in Japan—to broaden their choices for the future as well as to minimize the bias against acknowledging the achievements of women scientists compared to male scientists for similar work.”

The prize recognizes Aya’s contributions to high-energy astronomy with the IceCube detector, in particular, the study of the origins of the ultra-high-energy Universe where she has been leading the searches for cosmogenic neutrinos. The award, distributed by the Association for the Bright Future of Women Scientists, also acknowledges Aya’s support to young female physicists. The award ceremony will take place in Tokyo on Saturday, May 27, 2017.

It was in a dedicated search for cosmogenic neutrinos in IceCube that the first two PeV neutrinos were found. These two events, nicknamed Bert and Ernie, were then the highest energy neutrinos ever detected and spurred the analysis of the discovery of a flux of astrophysical neutrinos. In 2013, Aya was awarded the Young Scientist Prize of the International Union of Pure and Applied Physics (IUPAP) for her contributions to this work.

Female scientists are underrepresented in research institutions all around the world. In Japan, women in physics are around 10%, while the percentage in the U.S. is about 20%, and reaches 25% in Europe.

The Saruhashi Prize was established in 1981 by Katsuko Saruhashi, a Japanese geochemist, who made some of the first measurements of carbon dioxide and radioactive materials in ocean water. Saruhashi had earned a doctorate degree in chemistry in 1957 from the University of Tokyo, becoming the first woman to do so. One of her most famous quotes is “there are many women who have the ability to become great scientists. I would like to see the day when women can contribute to science and technology on an equal footing with men.”



In December 2016, the IceCube Collaboration published in Physical Review Letters a new search for cosmogenic neutrinos that resulted in two very high energy neutrinos, which are found to be of astrophysical origin with a 92.3% probability. The lack of evidence for cosmogenic neutrinos in a search of seven years of IceCube data places very strong constraints on the sources of UHECR. Proton-dominated sources are greatly disfavored, and testing mixed and heavy nuclei cosmic-ray sources will require much bigger instruments, such as an extension of IceCube or radio Askaryan neutrino detectors. Credit: IceCube Collaboration.

+ info Read the Saruhashi Prize release (in Japanese) (link)