Gamma-rays from kilonova: a potential probe of r-process nucleosynthesis

Abstract

The mergers of compact binaries with at least one neutron star component are the potential leading sites of the production and ejection of $r$-process elements. Discoveries of galactic binary pulsars, short gamma-ray bursts, and gravitational-wave detections have all been constraining the rate of these events, while the gravitational wave plus broadband electromagnetic coverage of binary neutron star merger (GW170817) has also placed constraints on the properties (mass and composition) of the merger ejecta. But uncertainties and ambiguities in modeling the optical and infrared emission make it difficult to definitively measure the distribution of heavy isotopes in these mergers. In contrast, gamma rays emitted in the decay of these neutron-rich ejecta may provide a more direct measurement of the yields. We calculate the gamma production in remnants of neutron star mergers, considering two epochs: a kilonova epoch, lasting about two weeks, and a much later epoch of tens and hundreds of thousands of years after the merger. For the kilonova epoch, when the expanding ejecta is still only partially transparent to gamma radiation, we use 3D radiative transport simulations to produce the spectra. We show that the gamma-ray spectra associated with beta- and alpha-decay provide a fingerprint of the ejecta properties and, for a sufficiently nearby remnant, may be detectable, even for old remnants. We compare our gamma spectra with the potential detection limits of next generation detectors, including the Lunar Occultation Explorer (LOX), the All-sky Medium Energy Gamma-ray Observatory (AMEGO), and the Compton Spectrometer and Imager (COSI). We show that fission models can be discriminated via the presence of short-lived fission fragments in the remnant spectra.

arXiv comment14 pages, 11 figures

References in corpus (84)

• The NumPy array: a structure for efficient numerical computation
• The Physics of Gamma-Ray Bursts
• Transient Events from Neutron Star Mergers
• Electromagnetic Counterparts of Compact Object Mergers Powered by the Radioactive Decay of R-process Nuclei
• Spectroscopic identification of r-process nucleosynthesis in a double neutron star merger
• The X-ray counterpart to the gravitational wave event GW 170817
• The Emergence of a Lanthanide-Rich Kilonova Following the Merger of Two Neutron Stars
• A "kilonova" associated with short-duration gamma-ray burst 130603B
• Double Compact Objects I: The Significance Of The Common Envelope On Merger Rates
• Production of all the r-process nuclides in the dynamical ejecta of neutron star mergers
• Comprehensive nucleosynthesis analysis for ejecta of compact binary mergers
• On the astrophysical robustness of neutron star merger r-process
• Effect of a High Opacity on the Light Curves of Radioactively Powered Transients from Compact Object Mergers
• Swift and NuSTAR observations of GW170817: detection of a blue kilonova
• Opacities and Spectra of the r-process Ejecta from Neutron Star Mergers
• Systematics of dynamical mass ejection, nucleosynthesis, and radioactively powered electromagnetic signals from neutron-star mergers
• The mass ejection from the merger of binary neutron stars
• What is the Most Promising Electromagnetic Counterpart of a Neutron Star Binary Merger?
• Identification of strontium in the merger of two neutron stars
• Formation Rates of Black Hole Accretion Disk Gamma-Ray Bursts
• Neutrino-driven winds from neutron star merger remnants
• Radiative Transfer Simulations for Neutron Star Merger Ejecta
• Dynamical Mass Ejection from Binary Neutron Star Mergers
• Delayed outflows from black hole accretion tori following neutron star binary coalescence
• Neutrino signatures and the neutrino-driven wind in Binary Neutron Star Mergers
• Three-dimensional GRMHD simulations of the remnant accretion disks from neutron star mergers: outflows and r-process nucleosynthesis
• The Locations of Short Gamma-ray Bursts as Evidence for Compact Object Binary Progenitors
• Dynamical mass ejection from the merger of asymmetric binary neutron stars: Radiation-hydrodynamics study in general relativity
• The long-term evolution of neutron star merger remnants - I. The impact of r-process nucleosynthesis
• The Electromagnetic Signals of Compact Binary Mergers
• Asymmetries in core-collapse supernovae from maps of radioactive ${}^{44}$Ti in CassiopeiaA
• Neutrino-driven winds in the aftermath of a neutron star merger: nucleosynthesis and electromagnetic transients
• Neutron Star Mergers Might not be the Only Source of r-Process Elements in the Milky Way
• r-Process Lanthanide Production and Heating Rates in Kilonovae
• The long-term evolution of neutron star merger remnants - II. Radioactively powered transients
• The Origin of r-Process Elements in the Milky Way
• Impact of ejecta morphology and composition on the electromagnetic signatures of neutron star mergers
• The Macronova in GRB 050709 and the GRB/macronova connection
• What Can the Accretion Induced Collapse of White Dwarfs Really Explain?
• GRB 080503: Implications of a Naked Short Gamma-Ray Burst Dominated by Extended Emission
• The Spatial Distribution of Coalescing Neutron Star Binaries: Implications for Gamma-Ray Bursts
• Short GRB 130603B: Discovery of a jet break in the optical and radio afterglows, and a mysterious late-time X-ray excess
• Full Transport Model of GW170817-Like Disk Produces a Blue Kilonova
• The lightcurve of the macronova associated with the long-short burst GRB 060614
• The first direct double neutron star merger detection: implications for cosmic nucleosynthesis
• Cobalt-56 gamma-ray emission lines from the type Ia supernova 2014J
• Neutron Star Mergers as sites of r-process Nucleosynthesis and Short Gamma-Ray Bursts
• r-Process Nucleosynthesis: Connecting Rare-Isotope Beam Facilities with the Cosmos
• The $R$-Process Alliance: First Release from the Southern Search for $r$-Process-Enhanced Stars in the Galactic Halo
• Short GRB 160821B: a reverse shock, a refreshed shock, and a well-sampled kilonova
• Outflows from accretion disks formed in neutron star mergers: effect of black hole spin
• The distribution of radioactive ${}^{44}$Ti in Cassiopeia A
• Radioactive decay products in neutron star merger ejecta: heating efficiency and $\gamma$-ray emission
• Dynamics, nucleosynthesis, and kilonova signature of black hole - neutron star merger ejecta
• The impact of individual nuclear masses on $r$-process abundances
• Advanced LIGO Constraints on Neutron Star Mergers and R-Process Sites
• Using excitation-energy dependent fission yields to identify key fissioning nuclei in r-process nucleosynthesis
• $\beta$-delayed fission in $r$-process nucleosynthesis
• Actinide Production in Neutron-Rich Ejecta of a Neutron Star Merger
• General Relativistic Magnetohydrodynamic Simulations of Binary Neutron Star Mergers with the APR4 Equation of State
• Statistical Hauser-Feshbach theory with width fluctuation correction including direct reaction channels for neutron induced reaction at low energies
• Gamma-Ray Lines from Asymmetric Supernovae
• First Results from the CARIBU Facility: Mass Measurements on the r-Process Path
• A new delay time distribution for merging neutron stars tested against Galactic and cosmic data
• GRB beaming and gravitational-wave observations
• Neutron-gamma competition for $\beta$-delayed neutron emission
• From actinides to zinc: Using the full abundance pattern of the brightest star in Reticulum II to distinguish between different r-process sites
• Infrared emission from kilonovae: the case of the nearby short hard burst GRB 160821B
• Gamma-Rays from Single Lobe Supernova Explosions
• The lanthanide fraction distribution in metal-poor stars: a test of neutron star mergers as the dominant r-process site
• Estimation of M1 scissors mode strength for deformed nuclei in the medium to heavy mass region by statistical Hauser-Feshbach model calculations
• Unified 1-D Simulations of Gamma-Ray Line Emission from Type Ia Supernovae
• Expectations for the Hard X-ray Continuum and Gamma-ray Line Fluxes from the Type Ia supernova SN 2014J in M82
• Probing the production of actinides under different r-process conditions
• Supernovae as the Site of the r-Process: Implications for Gamma-Ray Astronomy
• Analytic heating rate of neutron star merger ejecta derived from Fermi's theory of beta decay
• Impact of Pulsar and Fallback Sources on Multifrequency Kilonova Models
• Finding the remnants of the Milky Way's last neutron star mergers
• Nucleosynthesis of elements in gamma ray bursts engines
• Positrons and 511 keV radiation as tracers of recent binary neutron star mergers
• Binary neutron star merger rate via the luminosity function of short gamma-ray bursts
• Radioactive $\gamma$-Ray Emissions from Neutron Star Mergers
• The Location and Environments of Neutron Star Mergers in an Evolving Universe
• X-ray Decay Lines from Heavy Nuclei in Supernova Remnants as a Probe of the r-Process Origin and the Birth Periods of Magnetars

Cited by in corpus (23)

• Origin of the Heaviest Elements: the Rapid Neutron-Capture Process
• Modeling Kilonova Light Curves: Dependence on Nuclear Inputs
• Neutrino absorption and other physics dependencies in neutrino-cooled black-hole accretion disks
• Neutron Star Mergers and How to Study Them
• Nucleosynthesis and observation of the heaviest elements
• Actinide opacities for modeling the spectra and light curves of kilonovae
• Multi-messenger-Athena Synergy White Paper
• MeV Gamma Rays from Fission: A Distinct Signature of Actinide Production in Neutron Star Mergers
• r-Process Radioisotopes from Near-Earth Supernovae and Kilonovae
• Reticulum II: Particle Dark Matter and Primordial Black Holes Limits
• Gamma-Ray Emission Produced by $r$-process Elements from Neutron Star Mergers
• Radioactively-Powered Gamma-Ray Transient Associated with a Kilonova from Neutron Star Merger
• Long-lived neutron-star remnants from asymmetric binary neutron star mergers: element formation, kilonova signals and gravitational waves
• Isochronic evolution and the radioactive decay of r-process nuclei
• Angle-dependent in-situ fast flavor transformations in post-neutron star merger disks
• Gamma-rays from kilonovae and the cosmic gamma-ray background
• Let there be neutrons! Hadronic photoproduction from a large flux of high-energy photons
• Directed search for continuous gravitational waves from the possible kilonova remnant G4.8+6.2
• Nuclear ${\beta }^{-}$-decay with statistical de-excitation
• Binary Neutron Star (BNS) merger: What we learned from relativistic ejecta of GW/GRB~170817A
• How Do Nuclear Isomers Influence the Gamma-Ray Bursts in Binary Neutron Star Mergers?
• Impact of in situ nuclear networks and atomic opacities on neutron star merger ejecta dynamics, nucleosynthesis, and kilonovae
• Gamma-ray Signatures of r-Process Radioactivity from the Collapse of Magnetized White Dwarfs