r-Process Nucleosynthesis and Radioactively Powered Transients from Magnetar Giant Flares

Abstract

We present nucleosynthesis and light-curve predictions for a new site of the rapid neutron capture process ($r$-process) from magnetar giant flares (GFs). Motivated by observations indicating baryon ejecta from GFs, Cehula et al. (2024) proposed mass ejection occurs after a shock is driven into the magnetar crust during the GF. We confirm using nuclear reaction network calculations that these ejecta synthesize moderate yields of third-peak $r$-process nuclei and more substantial yields of lighter $r$-nuclei, while leaving a sizable abundance of free neutrons in the outermost fastest expanding ejecta layers. The final $r$-process mass fraction and distribution are sensitive to the relative efficiencies of $\alpha$-capture and $n$-capture freeze-outs. We use our nucleosynthesis output in a semi-analytic model to predict the light curves of novae breves, the transients following GFs powered by radioactive decay. For a baryonic ejecta mass similar to that inferred of the 2004 Galactic GF from SGR 1806-20, we predict a peak UV/optical luminosity of $\sim 10^{39}$-$10^{40}\mathrm{erg}{\mathrm{s}}^{-1}$ at $\sim 10$-$15$ minutes, rendering such events potentially detectable following a gamma-ray trigger by wide-field transient monitors such as ULTRASAT/UVEX to several Mpc. The peak luminosity and timescale of the transient increase with the GF strength due to the larger ejecta mass. Although GFs likely contribute 1-10% of the total Galactic $r$-process budget, their short delay-times relative to star-formation make them an attractive source to enrich the earliest generations of stars.

19 pages, 9 figures

References in corpus (89)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Multi-messenger Observations of a Binary Neutron Star Merger
• A bright millisecond radio burst of extragalactic origin
• Nuclear ground-state masses and deformations: FRDM(2012)
• Swope Supernova Survey 2017a (SSS17a), the Optical Counterpart to a Gravitational Wave Source
• Magnetars
• A Repeating Fast Radio Burst
• A fast radio burst associated with a Galactic magnetar
• A bright millisecond-duration radio burst from a Galactic magnetar
• Shell-model calculations of stellar weak interaction rates: II. Weak rates for nuclei in the mass range A=45-65 in supernovae environment
• Optical emission from a kilonova following a gravitational-wave-detected neutron-star merger
• An exceptionally bright flare from SGR1806-20 and the origins of short-duration gamma-ray bursts
• Opacities and Spectra of the r-process Ejecta from Neutron Star Mergers
• Magnetorotationally driven Supernovae as the origin of early galaxy $r$-process elements?
• Gamma-Ray Observations of a Giant Flare from The Magnetar SGR 1806-20
• An extreme magneto-ionic environment associated with the fast radio burst source FRB 121102
• Kilonovae
• A giant, periodic flare from the soft gamma repeater SGR1900+14
• Magnetars: the physics behind observations
• Magnetar Spindown, Hyper-Energetic Supernovae, and Gamma Ray Bursts
• The Giant Flare of 1998 August 27 from SGR 1900+14: II. Radiative Mechanism and Physical Constraints on the Source
• Neutrino-Cooled Accretion Disks around Spinning Black Hole
• Radioactivity and thermalization in the ejecta of compact object mergers and their impact on kilonova light curves
• Shock Breakout in Core-Collapse Supernovae and its Neutrino Signature
• Where, oh where has the r-process gone?
• The Physics of Protoneutron Star Winds: Implications for r-Process Nucleosynthesis
• Magnetorotational Core-Collapse Supernovae in Three Dimensions
• Magnetars: Properties, Origin and Evolution
• Merger and Mass Ejection of Neutron-Star Binaries
• Systematic Opacity Calculations for Kilonovae
• Observing the Next Galactic Supernova
• 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
• A concordance picture of FRB 121102 as a flaring magnetar embedded in a magnetized ion-electron wind nebula
• A magnetar origin for the kilonova ejecta in GW170817
• An expanding radio nebula produced by a giant flare from the magnetar SGR 1806-20
• Fission barriers of neutron-rich and superheavy nuclei calculated with the ETFSI method
• The r-process in proto-neutron-star wind revisited
• Neutron-powered precursors of kilonovae
• Magnetar giant flares and afterglows as relativistic magnetized explosions
• Neutron Star Mergers as sites of r-process Nucleosynthesis and Short Gamma-Ray Bursts
• Proto-Neutron Star Winds with Magnetic Fields and Rotation
• SkyNet: A modular nuclear reaction network library
• Fast Radio Bursts from Magnetars Born in Binary Neutron Star Mergers and Accretion Induced Collapse
• Magnetic Deformation of Magnetars for the Giant Flares of the Soft Gamma-Ray Repeaters
• The Giant Flare of 1998 August 27 from SGR 1900+14: I. An Interpretive Study of BeppoSAX and Ulysses Observations
• Implications of a "Fast Radio Burst" from a Galactic Magnetar
• Science with a wide-field UV transient explorer
• Discovery of a Radio Source following the 27 December 2004 Giant Flare from SGR 1806-20
• A Relativistic Particle Outburst From The Soft Gamma-Ray Repeater SGR1900+14
• The Multi-Messenger Matrix: the Future of Neutron Star Merger Constraints on the Nuclear Equation of State
• Formation Rates and Evolution Histories of Magnetars
• Dynamics of Strongly Twisted Relativistic Magnetospheres
• Radioactive decay products in neutron star merger ejecta: heating efficiency and $\gamma$-ray emission
• The First Hours of the GW170817 Kilonova and the Importance of Early Optical and Ultraviolet Observations for Constraining Emission Models
• Neutron-induced astrophysical reaction rates for translead nuclei
• The first giant flare from SGR 1806-20: observations with the INTEGRAL SPI Anti-Coincidence Shield
• GW170817$-$the first observed neutron star merger and its kilonova: implications for the astrophysical site of the r-process
• Diagnosing the outflow from the SGR 1806-20 Giant Flare with Radio Observations
• The effects of r-process heating on fall-back accretion in compact object mergers
• Physics of Luminous Transient Light Curves: A New Relation Between Peak Time and Luminosity
• Stellar origin of the 182Hf cosmochronometer and the presolar history of solar system matter
• Full Transport General Relativistic Radiation Magnetohydrodynamics for Nucleosynthesis in Collapsars
• Neutron star mergers and rare core-collapse supernovae as sources of r-process enrichment in simulated galaxies
• Giant Flare in SGR 1806-20 and Its Compton Reflection from the Moon
• A Re-brightening of the Radio Nebula associated with the 2004 December 27 giant flare from SGR 1806--20
• Identification of a Local Sample of Gamma-Ray Bursts Consistent with a Magnetar Giant Flare Origin
• Core-collapse Supernova Explosions Driven by the Hadron-quark Phase Transition as a Rare $r$-process Site
• The Influence Of Neutron Capture Rates On The Rare Earth Region Of The r-Process Abundance Pattern
• Can Neutron-Star Mergers Explain the r-process Enrichment in Globular Clusters?
• The Giant Flare of December 27, 2004 from SGR 1806-20
• The Birthrate of Magnetars
• The Growth, Polarization, and Motion of the Radio Afterglow from the Giant Flare from SGR 1806-20
• On the trigger mechanisms for SGR giant flares
• Neutrino-heated winds from millisecond proto-magnetars as sources of the weak r-process
• High-entropy ejections from magnetized proto-neutron star winds: implications for heavy element nucleosynthesis
• Signatures of R-process Enrichment in Supernovae from Collapsars
• Mass loading of pulsar winds
• Timing the r-Process Enrichment of the Ultra-Faint Dwarf Galaxy Reticulum II
• Correlations of r-Process Elements in Very Metal-Poor Stars as Clues to their Nucleosynthesis Sites
• Common envelope jets supernova r-process yields can reproduce $[Eu/Fe]$ abundance evolution in the Galaxy
• Dynamics of baryon ejection in magnetar giant flares: implications for radio afterglows, r-process nucleosynthesis, and fast radio bursts
• SGR 1806-20 distance and dust properties in molecular clouds by analysis of a flare x-ray echoes
• Electromagnetic signals from the decay of free neutrons in the first hours of neutron star mergers
• Photoionization Models for High Density Gas
• Three-Dimensional General-Relativistic Simulations of Neutrino-Driven Winds from Rotating Proto-Neutron Stars
• Radiatively driven evaporation from magnetar's surface
• Proto-Neutron Star Convection and the Neutrino-Driven Wind: Implications for the r-Process
• The Evryscope Fast Transient Engine: Real-Time Detection for Rapidly Evolving Transients

Cited by in corpus (2)

• Proton-rich production of lanthanides: the $\nu i$ process
• Novae breves from magnetar giant flares: Potential probes of neutron star crusts