THE DETECTION OF GRAVITATIONAL WAVES (GW) FROM BINARY BLACK HOLE MERGERS HAS BEEN AN HISTORICAL TRANSFORMATIVE EVENT IN PHYSICS AND ASTRONOMY HERALDED BY MOST AS THE BEGINNING OF MULTI-MESSENGER ASTRONOMY. WITH THE INCREASE OF SENSITIVITY OVER THE NEXT FEW YEARS LIGO AND VIRGO ARE PREDICTED TO DETECT MERGERS FROM NEUTRON-STAR (NS) BINARIES. THESE ARE EXPECTED TO BE THE FIRST TRUE MULTI-MESSENGER SOURCES BEING THE PROGENITORS OF SHORT-DURATION GAMMA-RAY BURST (SGRB). THE SIMULTANEOUS DETECTION OF A GRAVITATIONAL ELECTROMAGNETIC AND POSSIBLY NEUTRINO SIGNALS FROM THE SAME SOURCE WOULD DRAMATICALLY ENHANCE THE SCIENTIFIC OUTPUT OF EACH INDIVIDUAL DETECTION. IMPORTANT DETAILS OF THE CONNECTION BETWEEN SGRBS AND NS BINARY MERGERS ARE HOWEVER POORLY KNOWN. THESE INCLUDE THE NATURE OF THE MERGING COMPACT OBJECTS THEIR EQUATION OF STATE THE PHYSICS OF SGRB JETS - SUCH AS THEIR LORENTZ FACTORS AND OPENING ANGLES AND THE POSSIBILITY OF SMALL TEMPORAL DELAYS AMONG THE GW NEUTRINO AND GAMMA-RAY SIGNALS. IN VIEW OF THE EXPECTED INCREASED SENSITIVITY OF LIGO DURING THE UPCOMING OBSERVING PERIOD AND BEYOND THERE IS URGENT NEED OF IMPROVING OUR UNDERSTANDING OF THE PHYSICS OF SGRBS TO SUPPORT THE DETECTION OF GWS (AND POSSIBLY NEUTRINOS) AND TO DEVELOP A CONTEXT IN WHICH THE EXPECTED MULTI-MESSENGER SIGNAL CAN BE PROPERLY INTERPRETED AND ITS POTENTIAL FULLY EXPLOITED. TO ACHIEVE SUCH GOALS WE PROPOSE TO CARRY OUT A COMPREHENSIVE STUDY OF RELATIVISTIC JETS FROM COMPACT BINARY MERGERS EXPLOITING THE MOST RECENT ADVANCES IN NUMERICAL TECHNIQUES DEVELOPED WITHIN THIS RESEARCH GROUP. THE ANSATZ OF THIS STUDY WILL BE THAT WITHIN A SHORT TIME AFTER A COMPACT MERGER A RELATIVISTIC JET IS CREATED. SUBSEQUENTLY THE JET INTERACTS WITH THE MERGER ENVIRONMENT IMPRINTING A SIGNATURE THAT CAN BE DETECTED IN THE TEMPORAL AND SPECTRAL PROPERTIES OF THE PROMPT RADIATION BOTH IN ITS ELECTROMAGNETIC AND NEUTRINO COMPONENTS. ANALOGOUS DYNAMICAL EFFECTS HAVE BEEN OBSERVED AND STUDIED EXTENSIVELY FOR LONG-DURATION GRBS. SINCE DIFFERENT PROGENITORS PRODUCE DIFFERENT ENVIRONMENTS AND PHYSICAL CONDITIONS THE PROPERTIES OF THE GAMMA-RAY AND NEUTRINO SIGNALS WILL BE A PROXY TO THE PHYSICS OF THE MERGER AND ULTIMATELY TO THE EXPECTED GW SIGNAL. WE WILL PERFORM A COMBINATION OF STATE-OF-THEART NUMERICAL SIMULATIONS COVERING ALL DIFFERENT PHASES OF THE EVENT INCLUDING THE COALESCENCE AND MERGER OF THE PROGENITOR COMPACT BINARY SYSTEM THE SMALL TO LARGE SCALE JET DYNAMICS AND THE RADIATION TRANSFER PHYSICS LEADING TO ELECTROMAGNETIC AND NEUTRINO SIGNALS. OUR PRODUCTS WILL INCLUDE MULTI MESSENGER PREDICTIONS NOT ONLY FOR ON-AXIS BURSTS THOSE POINTING DIRECTLY AT EARTH BUT ALSO FOR OFF-AXIS EVENTS THOSE WITH JETS THAT POINT AWAY FROM OUR DETECTORS. OFF-AXIS BURSTS ARE EXPECTED TO HAVE A DIM ELECTROMAGNETIC SIGNATURE BUT THEY CONSTITUTE THE DOMINANT POPULATION OF LIGO DETECTED NS BINARY MERGERS.
$432,021FY2017National Aeronautics and Space AdministrationNASA
Oregon State University, Corvallis OR