Radiative Opacity: A Link between Atomic Physics and Gravitational Wave Spectroscopy
ORAL · Invited
Abstract
The recent (2017) observation [1] of gravitational-wave event GW170817
accompanied by electromagnetic (EM) signals provided a clear example
of a "kilonova", which can result from the merger of two neutron stars.
The EM signal from this event was rather dramatic, spanning the infrared
to x-ray portions of the spectrum. More generally, the EM radiation
from a kilonova is powered by gamma rays produced during the radioactive decay
of elements that are synthesized during the event, and the atomic properties
of the resulting ejecta material are predicted to play an important role
in characterizing the emission from these transient events. We use the Los Alamos
suite of atomic physics and plasma modeling codes [2] to investigate the
use of detailed, fine-structure opacities [3-4] to model the EM emission
from kilonovae. Our simulations predict emission in a range of EM bands,
depending on issues such as the presence of winds, elemental composition,
and viewing angle. This talk emphasizes various atomic-physics aspects
of the spectral modeling of neutron star mergers, including the use of curated
energies from the NIST Atomic Spectra Database [6] to calibrate the atomic
level energies for lanthanide elements.
[1] B.P. Abbott et al, Astrophys. J. Lett. 848, L12 (2017).
[2] C.J. Fontes, H.L. Zhang, J. Abdallah, Jr., R.E.H. Clark, D.P. Kilcrease,
J. Colgan, R.T. Cunningham, P. Hakel, N.H. Magee and M.E. Sherrill, J. Phys. B 48, 144014 (2015).
[3] C.J. Fontes, C.L. Fryer, A.L. Hungerford, R.T. Wollaeger, O. Korobkin, MNRAS 493, 4143 (2020).
[4] C.J. Fontes et al, MNRAS 519, 2862 (2023).
[5] A. Kramida, Yu. Ralchenko, J. Reader J., NIST ASD Team, 2025, NIST
Atomic Spectra Database (ver. 5.6.1). [Online]. Available: https://physics.nist.gov/asd.
accompanied by electromagnetic (EM) signals provided a clear example
of a "kilonova", which can result from the merger of two neutron stars.
The EM signal from this event was rather dramatic, spanning the infrared
to x-ray portions of the spectrum. More generally, the EM radiation
from a kilonova is powered by gamma rays produced during the radioactive decay
of elements that are synthesized during the event, and the atomic properties
of the resulting ejecta material are predicted to play an important role
in characterizing the emission from these transient events. We use the Los Alamos
suite of atomic physics and plasma modeling codes [2] to investigate the
use of detailed, fine-structure opacities [3-4] to model the EM emission
from kilonovae. Our simulations predict emission in a range of EM bands,
depending on issues such as the presence of winds, elemental composition,
and viewing angle. This talk emphasizes various atomic-physics aspects
of the spectral modeling of neutron star mergers, including the use of curated
energies from the NIST Atomic Spectra Database [6] to calibrate the atomic
level energies for lanthanide elements.
[1] B.P. Abbott et al, Astrophys. J. Lett. 848, L12 (2017).
[2] C.J. Fontes, H.L. Zhang, J. Abdallah, Jr., R.E.H. Clark, D.P. Kilcrease,
J. Colgan, R.T. Cunningham, P. Hakel, N.H. Magee and M.E. Sherrill, J. Phys. B 48, 144014 (2015).
[3] C.J. Fontes, C.L. Fryer, A.L. Hungerford, R.T. Wollaeger, O. Korobkin, MNRAS 493, 4143 (2020).
[4] C.J. Fontes et al, MNRAS 519, 2862 (2023).
[5] A. Kramida, Yu. Ralchenko, J. Reader J., NIST ASD Team, 2025, NIST
Atomic Spectra Database (ver. 5.6.1). [Online]. Available: https://physics.nist.gov/asd.
*This work was supported by the US Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of US Department of Energy (Contract No. 89233218CNA000001).
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Presenters
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Christopher J Fontes
- Los Alamos National Laboratory (LANL)