Retainment of r-process material in dwarf galaxies

Abstract

The synthesis of $r$-process elements is known to involve extremely energetic explosions. At the same time, recent observations find significant $r$-process enrichment even in extremely small ultra-faint dwarf (UFD) galaxies. This raises the question of retainment of those elements within their hosts. We estimate the retainment fraction and find that it is large $\sim 0.9$, unless the $r$-process event is very energetic ($\gtrsim 10^{52}$erg) and / or the host has lost a large fraction of its gas prior to the event. We estimate the $r$-process mass per event and rate as implied by abundances in UFDs, taking into account imperfect retainment and different models of UFD evolution. The results are consistent with previous estimates (Beniamini et al. 2016) and with the constraints from the recently detected macronova accompanying a neutron star merger (GW170817). We also estimate the distribution of abundances predicted by these models. We find that $\sim 0.07$ of UFDs should have $r$-process enrichment. The results are consistent with both the mean values and the fluctuations of [Eu/Fe] in galactic metal poor stars, supporting the possibility that UFDs are the main 'building blocks' of the galactic halo population.

13 pages, 6 figures, published in MNRAS

References in corpus (38)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Multi-messenger Observations of a Binary Neutron Star Merger
• A gravitational-wave standard siren measurement of the Hubble constant
• Origin of the heavy elements in binary neutron-star mergers from a gravitational wave event
• Spectroscopic identification of r-process nucleosynthesis in a double neutron star merger
• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis
• Illuminating Gravitational Waves: A Concordant Picture of Photons from a Neutron Star Merger
• Formation of Double Neutron Star Systems
• Comprehensive nucleosynthesis analysis for ejecta of compact binary mergers
• Magnetorotationally driven Supernovae as the origin of early galaxy $r$-process elements?
• A Radio Counterpart to a Neutron Star Merger
• Neutrino-driven winds from neutron star merger remnants
• The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. V. Rising X-ray Emission from an Off-Axis Jet
• The Search for the Missing Baryons at Low Redshift
• The Quenching of the Ultra-Faint Dwarf Galaxies in the Reionization Era
• The dynamical mass ejection from binary neutron star mergers: Radiation-hydrodynamics study in general relativity
• Relativistic neutron star merger simulations with non-zero temperature equations of state I. Variation of binary parameters and equation of state
• The Origin of r-Process Elements in the Milky Way
• Complete element abundances of nine stars in the r-process galaxy Reticulum II
• The Distance to NGC 4993: The Host Galaxy of the Gravitational-wave Event GW170817
• Galactic r-process enrichment by neutron star mergers in cosmological simulations of a Milky Way-mass galaxy
• The Dearth of Neutral Hydrogen in Galactic Dwarf Spheroidal Galaxies
• On the Conditions for Neutron-Rich Gamma-Ray Burst Outflows
• The Star Formation Histories of Local Group Dwarf Galaxies III. Characterizing Quenching in Low-Mass Galaxies
• Neutron Star Mergers as the Origin of r-Process Elements in the Galactic Halo Based on the Sub-halo Clustering Scenario
• Early flattening of dark matter cusps in dwarf spheroidal galaxies
• The unpolarized macronova associated with the gravitational wave event GW170817
• Supernova Fallback: A Possible Site for the r-Process
• Natal Kicks and Time Delays in Merging Neutron Star Binaries - Implications for r-process nucleosynthesis in Ultra Faint Dwarfs and in the Milky Way
• r-process Production Sites as inferred from Eu Abundances in Dwarf Galaxies
• Distance and properties of NGC 4993 as the host galaxy of a gravitational wave source, GW170817
• Compact Stellar Binary Assembly in the First Nuclear Star Clusters and r-Process Synthesis in the Early Universe
• Detailed Abundance Analysis of the Brightest Star in Segue 2, the Least Massive Galaxy
• The Unprecedented Properties of the First Electromagnetic Counterpart to a Gravitational Wave Source
• Neutrino-heated winds from rotating proto-magnetars
• The Origin of the Heaviest Metals in Most Ultra-Faint Dwarf Galaxies
• Thermonuclear explosion of rotating massive stars could explain core-collapse supernovae

Cited by in corpus (30)

• The Faintest Dwarf Galaxies
• r-Process Nucleosynthesis: Connecting Rare-Isotope Beam Facilities with the Cosmos
• Where are the most ancient stars in the Milky Way?
• The R-Process Alliance: First Release from the Northern Search for r-Process Enhanced Metal-Poor Stars in the Galactic Halo
• A lesson from GW170817: most neutron star mergers result in tightly collimated successful GRB jets
• Kinematics of Highly R-Process-Enhanced Field Stars: Evidence for an Accretion Origin and Detection of Several Groups from Disrupted Satellites
• The Gravitational waves merger time distribution of binary neutron star systems
• A deep survey of short GRB host galaxies over $z\sim 0-2$: implications for offsets, redshifts, and environments
• The common envelope jets supernova (CEJSN) r-process scenario
• The lanthanide fraction distribution in metal-poor stars: a test of neutron star mergers as the dominant r-process site
• Observable Features of GW170817 Kilonova Afterglow
• Neutron Star Mergers Are the Dominant Source of the r-process in the Early Evolution of Dwarf Galaxies
• Signatures of R-process Enrichment in Supernovae from Collapsars
• Neutron star binary orbits in their host potential: effect on early r-process enrichment
• Evolution of neutron capture elements in dwarf galaxies
• R-process enrichment in ultrafaint dwarf galaxies
• Positrons and 511 keV radiation as tracers of recent binary neutron star mergers
• Turbulent mixing of r-process elements in the Milky Way
• Simulating Metal Mixing of Both Common and Rare Enrichment Sources in a Low Mass Dwarf Galaxy
• Highly r-process enhanced stars in ultra-faint dwarf galaxies
• The R-Process Alliance: Discovery of a low-alpha, r-Process-Enhanced Metal-Poor Star in the Galactic Halo
• Evidence for r-process delay in very metal-poor stars
• s-process Enirchment of Ultrafaint Dwarf Galaxies
• Radioactively-Powered Gamma-Ray Transient Associated with a Kilonova from Neutron Star Merger
• Probing binary neutron star mergers in dense environments using afterglow counterparts
• The impact of turbulent mixing on the galactic r-process enrichment by binary neutron star mergers
• Neutron-capture elements in dwarf galaxies III: A homogenized analysis of 13 dwarf spheroidal and ultra-faint galaxies
• Did a Kilonova Set Off in Our Galactic Backyard 3.5 Myr ago?
• Semi-analytic modelling of the europium production by neutron star mergers in the halo of the Milky Way
• Evolutionary tracks of binary neutron star progenitors across cosmic times