News

Our group is now part of the leadership team of a new $3.25M NSF Focus Research Hub dedicated to address fundamental questions in nuclear physics using multi-messenger observations of merging neutron stars. The hub is led by the University of Tennessee, Knoxville, and will directly support Penn State, Syracuse University, Indiana University Bloomington, and the University of Houston over a period of five years. Other Penn State professors involved in this initiative are Ashley Villar (Assistant Professor of Astronomy & Astrophysics), Kathleen Hill (Director of Penn State’s Center for Science in the Schools), and B. S. Sathyaprakash (Elsbach Professor of Physics and Professor of Astronomy and Astrophysics).

For more information, see the Penn State press release.

The new hub’s webpage is here.

In a recent study, we investigated the phenomenon of QCD phase transitions to deconfined quark matter in the context of binary neutron star mergers. We computed gravitational wave signatures of such a phase transition and explored its thermodynamic consequences. We found that binaries with equations of state supporting a quark phase become more compact and are more susceptible to collapsing to a black hole. We also computed electromagnetic signatures of QCD phase transitions and observed that a merger of binaries producing a remnant with a quark core can be dimmer as compared to exclusively hadronic mergers at early times i.e. from a few days to a few weeks following the merger. On the contrary, at late times, on the order of several months to years, the quark mergers can start to become more luminous.

Our group is one of the 13  members of the new Network for Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS) Physics Frontier Center,  funded by the National Science Foundation. The center, formally approved Aug. 10, will launch Sept. 1, 2020.

You can read more about N3AS on the press release here.

See also the Penn State version of the press release.

In an article just published on Monthly Notices of the Royal Astronomical Society we presented the first general-relativistic simulations with microphysics and neutrinos to explore the dynamics of merging binary neutron star systems with large mass ratios. We found that the lower mass neutron star in these binaries is tidally disrupted by the primary neutron star shortly prior to merger. The accretion of the tidal debris can cause the more massive neutron star to collapse and form a black hole surrounded by a large accretion disk. Our simulations showed that, contrary to common expectations, neutron star mergers with prompt black hole formation can be accompanied by bright electromagnetic counterparts. Our work is featured in press releases by Pittsburgh Supercomputing Center and the Pennsylvania State University.

Our group has been awarded a DOE Early Career Award! The DOE Early Career program is designed to bolster the nation’s scientific workforce by providing support to exceptional researchers during crucial early career years, when many scientists do their most formative work.

The award will fund the development of a new open source numerical relativity code able to perform neutron star merger simulations with advanced neutrino microphysics and exploiting next generation exascale supercomputers.

For more information, see also the University announcement.