We present VULCAN/2D multi-group flux-limited-diffusion radiation hydrodynamics simulations of binary neutron star ( BNS ) mergers , using the Shen equation of state , covering \buildrel { \scriptstyle > } \over { \scriptstyle \sim } 100 ms , and starting from azimuthal-averaged 2D slices obtained from 3D SPH simulations of Rosswog & Price for 1.4 M _ { \odot } ( baryonic ) neutron stars with no initial spins , co-rotating spins , and counter-rotating spins .
Snapshots are post-processed at 10 ms intervals with a multi-angle neutrino-transport solver .
We find polar-enhanced neutrino luminosities , dominated by \bar { \nu } _ { e } and “ \nu _ { \mu } ” neutrinos at peak , although \nu _ { e } emission may be stronger at late times .
We obtain typical peak neutrino energies for \nu _ { e } , \bar { \nu } _ { e } , and “ \nu _ { \mu } ” of \sim 12 , \sim 16 , and \sim 22 MeV .
The super-massive neutron star ( SMNS ) formed from the merger has a cooling timescale of \buildrel { \scriptstyle < } \over { \scriptstyle \sim } 1 s. Charge-current neutrino reactions lead to the formation of a thermally-driven bipolar wind with ¡ \dot { M } ¿ \sim 10 ^ { -3 } M _ { \odot } s ^ { -1 } , baryon-loading the polar regions , and preventing any production of a \gamma -ray burst prior to black-hole formation .
The large budget of rotational free energy suggests magneto-rotational effects could produce a much greater polar mass loss .
We estimate that \buildrel { \scriptstyle < } \over { \scriptstyle \sim } 10 ^ { -4 } M _ { \odot } of material with electron fraction in the range 0.1-0.2 become unbound during this SMNS phase as a result of neutrino heating .
We present a new formalism to compute the \nu _ { i } \bar { \nu } _ { i } annihilation rate based on moments of the neutrino specific intensity computed with our multi-angle solver .
Cumulative annihilation rates , which decay as t ^ { -1.8 } , decrease over our 100 ms window from a few \times 10 ^ { 50 } to \sim 10 ^ { 49 } erg s ^ { -1 } , equivalent to a few \times 10 ^ { 54 } to \sim 10 ^ { 53 } e ^ { - } e ^ { + } pairs per second .