Galactic 26Al traces metal loss through hot chimneys

Abstract

Radioactive 26Al is an excellent tracer for metal ejection in the Milky Way, and can provide a direct constraint on the modelling of supernova feedback in galaxy evolution. Gamma-ray observations of the 26Al decay line have found high velocities and hence require a significant fraction of the Galactic 26Al in the hot component. At the same time, meteoritic data combined with simulation results suggest that a significant amount of 26Al makes its way into stars before decay. We investigated the distribution into hot and cold channels with a simulation of a Milky-Way-like galaxy with massive-star feedback in superbubbles and with ejecta traced by 26Al. About 30-40 per cent of the ejecta remain hot, with typical cooling times of the order Gyr. 26Al traces the footpoints of a chimney-fed outflow that mixes metals turbulently into the halo of the model galaxy on a scale of at least 50 kpc. The rest diffuses into cold gas with temperatures less than about 10,000 K, and may therefore be quickly available for star formation. We discuss the robustness of the result by comparison to a simulation with a different global flow pattern. The branching ratio into hot and cold components is comparable to that of longer term average results from chemical evolution modelling of galaxies, clusters and the intracluster medium.

10 pages, 10 figures, accepted for MNRAS

References in corpus (26)

• Nucleosynthesis and Remnants in Massive Stars of Solar Metallicity
• The nucleosynthesis of Al26 and Fe60 in solar metallicity stars extending in mass from 11 to 120 Msun: the hydrostatic and explosive contributions
• The Laniakea supercluster of galaxies
• Simulations of Cosmic Chemical Enrichment
• A water budget dichotomy of rocky protoplanets from ${}^{26}$Al-heating
• The signature of 44Ti in Cassiopeia A revealed by IBIS/ISGRI on INTEGRAL
• Solar system genealogy revealed by extinct short-lived radionuclides in meteorites
• Early 56Ni decay γ-rays from SN2014J suggest an unusual explosion
• The History and Future of the Local and Loop I Bubbles
• Wind bubbles within H II regions around slowly moving stars
• Chemical Evolution on the Scale of Clusters of Galaxies: A Conundrum?
• The Galactic ${}^{26}$Al emission map as revealed by INTEGRAL/SPI
• Triggered Star Formation Inside the Shell of a Wolf-Rayet Bubble as the origin of the Solar System
• Feedback by massive stars and the emergence of superbubbles II. X-ray properties
• 26Al kinematics: superbubbles following the spiral arms? Constraints from the statistics of star clusters and HI supershells
• Gamma-ray Emission of 60Fe and 26Al Radioactivities in our Galaxy
• Triggering Active Galactic Nuclei in galaxy clusters
• Dynamics and Energy Loss in Superbubbles
• Tracing the Dynamical Mass in Galaxy Disks Using HI Velocity Dispersion and its Implications for the Dark Matter Distribution in Galaxies
• Comparing simulated ${}^{26}$Al maps to gamma-ray measurements
• Young stars as tracers of a barred-spiral Milky Way
• Synthetic ${}^{26}$Al emission from galactic-scale superbubble simulations
• Chemical enrichment of the intracluster medium by FR II radio sources
• Distribution and kinematics of 26Al in the Galactic disc
• Squeezed between shells? On the origin of the Lupus I molecular cloud. - II. APEX CO and GASS HI observations
• Probing gaseous halos of galaxies with radio jets

Cited by in corpus (4)

• Detection of magnetic fields in the circumgalactic medium of nearby galaxies using Faraday rotation
• The Positron Puzzle
• The radio continuum perspective on cosmic-ray transport in external galaxies
• Galactic Population Synthesis of Radioactive Nucleosynthesis Ejecta