2013/03/22 by Jennifer Barnes, Daniel Kasen · 586 citations
Physics and Astronomy · #Astronomy #Astrophysics #BL Lac object #Blazar #Compact star #Gamma ray #Gamma-ray bursts and supernovae #Light curve #Neutrino Physics Research #Nuclear physics research studies #Object (grammar) #Opacity #Optics #Physics #Stars #astro-ph.HE
paper · pdf · doi:10.1088/0004-637x/775/1/18
published in The Astrophysical Journal 775(1), 18 (IOP Publishing) · submitted to ApJ
arxiv created 2013/03/22 · openalex publication_date 2013/08/29 · arxiv updated 2015/06/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The coalescence of compact objects is a promising astrophysical source of detectable gravitational wave signals. The ejection of r -process material from such mergers may lead to a radioactively powered electromagnetic counterpart signal which, if discovered, would enhance the science returns. As very little is known about the optical properties of heavy r -process elements, previous light-curve models have adopted opacities similar to those of iron group elements. Here we consider the effect of heavier elements, particularly the lanthanides, which increase the ejecta opacity by several orders of magnitude. We include these higher opacities in time-dependent, multi-wavelength radiative transport calculations to predict the broadband light curves of one-dimensional models over a range of parameters (ejecta masses ∼10 −3 –10 −1 M ☉ and velocities ∼0.1–0.3 c ). We find that the higher opacities lead to much longer duration light curves which can last a week or more. The emission is shifted toward the infrared bands due to strong optical line blanketing, and the colors at later times are representative of a blackbody near the recombination temperature of the lanthanides ( T ∼ 2500 K). We further consider the case in which a second mass outflow, composed of 56 Ni, is ejected from a disk wind, and show that the net result is a distinctive two component spectral energy distribution, with a bright optical peak due to 56 Ni and an infrared peak due to r -process ejecta. We briefly consider the prospects for detection and identification of these transients.