FRIB hosts summer school on neutron-star merger

FRIB is hosting a summer school focused on the scientific discoveries resulting from the recent observation of a neutron-star merger.

The school, being held from 16-18 May, is titled “Neutron star mergers for non-experts: GW170817 in the multi-messenger astronomy and FRIB eras.” It brings together graduate students, postdoctoral researchers, and senior scientific experts working in nuclear physics, astrophysics, astronomy, and related areas to discuss the impact of the merger on nuclear science and nuclear astrophysics.

“This is a unique and unprecedented opportunity to bring all these subfields of physics together,” said the lead organizer, Professor Charles Horowitz of Indiana University.

Hosted by the FRIB Theory Alliance, a coalition of scientists from universities and national laboratories, this summer school has more than 80 attendees from around the world as well as over 20 Zoom connections. Attendance is more than twice the originally expected number.

The observation of this merger provides additional information for nuclear astrophysics, and it signals a new era in multi-messenger astronomy. This summer school is designed to allow a broader audience to better appreciate the developments resulting from the observation of the merger. Lecturers at the summer school are from Columbia University, Indiana University, Princeton University, the Canadian Institute for Theoretical Astrophysics, Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements (JINA-CEE), and Michigan State University.

For those who wish to participate online, the lectures are being livestreamed via Zoom.

“This is a crash course covering the wide range of physics relevant to understanding neutron star mergers, and gravitational wave event GW170817 in particular. This will help to give the students the tools they need to connect the science of FRIB to gravitational wave observations and in the future contribute to our understanding of the properties of neutron stars and the origin of the heavy elements in our galaxy,” said Luke Roberts, a lecturer at the school. 

FRIB Theory Alliance Managing Director Filomena Nunes said that “there was a tremendous and worldwide response when we sent out the announcement of the school, from truly passionate people who are now here learning more and sharing their excitement.”

Observing the neutron-star merger

In October 2017, the Gravitational Wave Laboratories LIGO and VIRGO announced the first observation of gravitational waves from the merger of two neutron stars on 17 August, in an event called GW170817. Immediate follow-up observations with 70 observatories around the world revealed a short gamma-ray burst and a so-called “kilo-nova” associated with the same event. A kilo-nova is the weeklong afterglow of a neutron star merger and is thought to be powered by the radioactive decay of rare isotopes produced and ejected during the merger.

The GW170817 event is a significant discovery with impact on nuclear astrophysics. It is the long-sought "smoking gun" observation that directly indicates a possible site for the rapid neutron capture process, or r-process, thought to be responsible for many of the heavy elements in nature.

The observations indicate that neutron star mergers occur frequently enough and eject enough material to be major nucleosynthesis sites. It is now more important than ever to understand the underlying nuclear physics to connect merger models with the new observations and to determine exactly which elements are produced in such events. In addition, the observations provide new information on the properties of neutron stars, which directly inform longstanding questions in nuclear science about the nature of nuclear matter.

JINA-CEE, a multi-institutional Physics Frontiers Center funded by the National Science Foundation (NSF), hosted a livestream discussion on 1 December 2017 to discuss the nuclear science impacts of the merger.

The FRIB Theory Alliance (FRIB-TA) is a coalition of scientists from universities and national laboratories who seek to foster advancements in theory related to diverse areas of FRIB science; optimize the coupling between theory and experiment; and stimulate the field by creating permanent theory positions across the country, attracting young talent through the national FRIB Theory Fellow Program, fostering interdisciplinary collaborations, and shepherding international initiatives. Learn more at the FRIB-TA website.

MSU is establishing FRIB as a new scientific user facility for the Office of Nuclear Physics in the U.S. Department of Energy Office of Science. Under construction on campus and operated by MSU, FRIB will enable scientists to make discoveries about the properties of rare isotopes in order to better understand the physics of nuclei, nuclear astrophysics, fundamental interactions, and applications for society, including in medicine, homeland security, and industry.