Lawrence Livermore National Laboratory

NuSTAR Examines Supernova Asymmetry

New results from NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) show that a supernova close to our galaxy experienced a single-sided explosion, providing compelling observational evidence that supernovae are not symmetric. A team of scientists including Livermore’s Michael Pivovaroff, Julia Vogel, Todd Decker, and Nicolai Brejnholt studied x-ray emissions taken with NuSTAR and found that the Supernova 1987A explosion was highly asymmetric. The results appeared in the May 8, 2015, edition of the high-profile journal Science.

Supernova 1987A is a supernova remnant that evolved from a core-collapse supernova. This type of explosion produces an isotope of titanium in its innermost ejecta, the layer of material directly above the newly formed remnant. The radioactive decay of this isotope provides a direct probe of the supernova engine. NuSTAR measurements confirm that heavy elements are moving at speeds several times faster than expected from spherically symmetric models. The image of Supernova 1987A—courtesy of the ALMA Observatory, A. Angelich, the Hubble Space Telescope, and Chandra X-Ray Observatory—shows newly formed dust in the center (red) and the expanding shock wave colliding with a ring of material (green and blue).

NuSTAR, a NASA Explorer-class mission launched in June 2012, is designed to detect the highest energy x-ray light in great detail. NuSTAR uses technology developed by Livermore for the Laboratory’s High Energy Focusing Telescope (HEFT). The x-ray-focusing abilities, optics principles, and fabrication approach of NuSTAR are based on those developed under the HEFT project. Pivovaroff and Vogel are part of the team that received a NASA award in September 2014 “for exceptional achievement in executing the NuSTAR science program leading to groundbreaking discoveries in high-energy astrophysics.”
Contact: Michael Pivovaroff (925) 422-7779 (

One Step Closer to Mimicking Gamma-ray Bursts

Using high-energy lasers, Laboratory researchers have produced a record number of electron–positron pairs, opening opportunities to study extreme astrophysical processes such as black-hole formation and gamma-ray bursts. In May of this year, Livermore physicist Hui Chen and her colleagues created nearly a trillion positrons, as compared to billions of positrons in previous experiments.

Positrons are antimatter particles having the same mass as an electron but the opposite charge. The generation of energetic electron–positron pairs is common in extreme astrophysical environments associated with the rapid collapse of stars and the formation of black holes. These pairs radiate their energy, producing extremely bright gamma-ray bursts, which are the brightest electromagnetic events known to occur in the universe, but the mechanism of how they are produced is still a mystery.

Electron–positron pairs are generated in the lab by shining intense laser light into a gold foil. This produces high-energy radiation, creating electron–positron pairs as the laser interacts with the nucleus of the gold atoms. The ability to create a large number of positrons using energetic lasers opens the door to several new avenues of antimatter research. Antimatter research could reveal why more matter than antimatter survived the Big Bang at the start of the universe, why the observable universe is apparently almost entirely matter, whether other places are almost entirely antimatter, and what might be possible if antimatter could be harnessed.
Contact: Hui Chen (925) 423-5974 (

Livermore Helps Advance Ebola Test

Researchers from Lawrence Livermore have assisted San Francisco Bay Area biomedical company Cepheid in advancing its Ebola virus detection test for use. The Livermore testing was performed by Reg Beer, Livermore’s medical diagnostics initiative program leader, and biomedical scientists Pejman Naraghi-Arani and Celena Carrillo. Cepheid, co-founded in 1996 by former Livermore researcher M. Allen Northrup, is a molecular diagnostics company that works to improve health care by developing, manufacturing, and marketing accurate and easy-to-use molecular systems and tests.

Laboratory researchers received a Cepheid GeneXpert system and experimental Ebola assay cartridges, testing them against non-Ebola bacterial and viral targets to demonstrate that the assay would only detect Ebola. “This exclusivity testing supported Cepheid’s successful request to the FDA for an emergency-use authorization with the current Ebola outbreak,” says Beer. Livermore scientists tested 25 target organisms, including inactivated RNA from multiple strains of Ebola virus and Marburg virus.

In addition to providing valuable accuracy and other data to the company, Livermore was also one of the first sites outside of Cepheid to use the assay, providing feedback on usability and user interface issues. The Laboratory’s collaboration with Cepheid is expected to continue as Livermore researchers provide the firm with an accurate quantification of viral RNA samples that would be used for testing. On May 13, 2015, Cepheid also announced that the World Health Organization had listed Cepheid’s Ebola test, which can deliver results in less than two hours, as eligible for procurement for Ebola-affected nations.
Contact: Reg Beer (925) 424-2232 (