Barnes, Jennifer (1) & Kasen D. (1) ((1) University of California, Berkeley; Lawrence Berkeley National Laboratory)
The coalescence of compact objects is a promising source of detectable gravitational wave (GW) signals. The science returns from a GW detection can be greatly enhanced by identifying an electromagnetic (EM) counterpart. The radioactive debris ejected in tidal tails during the inspiral of a binary neutron star system is thought to power a dim supernova-like event lasting for days after the merger. A major challenge to accurately modeling these transients is determining the opacities of the r-process material synthesized in the ejecta, as very little experimental line is data available for these heavy elements. Earlier radiative transfer studies calculated light curves assuming the opacities were similar to that of iron group elements. We test this assumption using the available experimental line data, and find that the presence of heavy elements, particularly the lanthanides, results in opacities orders of magnitude greater than that of iron alone. We refine our estimates using synthetic line lists generated through ab-initio atomic structure modeling. We compute light curves for a one-dimensional model of r-process ejecta using reasonable parameters (ejecta masses = 1e-2Msun and velocities = 0.1c). We find that the higher opacities lead to longer, flatter, and dimmer light curves than previously predicted.
See complete preprint –> http://adsabs.harvard.edu/abs/2013AAS…22134604B