Comparing simulated ${}^{26}$Al maps to gamma-ray measurements

Abstract

Context. The diffuse gamma-ray emission of ${}^{26}\mathrm{Al}$ at 1.8 MeV reflects ongoing nucleosynthesis in the Milky Way, and traces massive-star feedback in the interstellar medium due to its 1 Myr radioactive lifetime. Interstellar-medium morphology and dynamics are investigated in astrophysics through 3D hydrodynamic simulations in fine detail, as only few suitable astronomical probes are available. Aims. We compare a galactic-scale hydrodynamic simulation of the Galaxy's interstellar medium, including feedback and nucleosynthesis, with gamma-ray data on ${}^{26}\mathrm{Al}$ emission in the Milky Way extracting constraints that are only weakly dependent on the particular realisation of the simulation or Galaxy structure. Methods. Due to constraints and biases in both the simulations and the gamma-ray observations, such comparisons are not straightforward. For a direct comparison, we perform maximum likelihood fits of simulated sky maps as well as observation-based maximum entropy maps to measurements with INTEGRAL/SPI. To study general morphological properties, we compare the scale heights of ${}^{26}\mathrm{Al}$ emission produced by the simulation to INTEGRAL/SPI measurements.} Results. The direct comparison shows that the simulation describes the observed inner Galaxy well, but differs significantly from the observed full-sky emission morphology. Comparing the scale height distribution, we see similarities for small scale height features and a mismatch at larger scale heights. We attribute this to the prominent foreground emission sites that are not captured by the simulation.

Accepted for publication in A&A

References in corpus (5)

• Gamma-ray continuum emission from the inner Galactic region as observed with INTEGRAL/SPI
• Spectral and intensity variations of Galactic 26^Al emission
• The Galactic ${}^{26}$Al emission map as revealed by INTEGRAL/SPI
• A fundamental test for stellar feedback recipes in galaxy simulations
• Background modelling for $\gamma$-ray spectroscopy with INTEGRAL/SPI

Cited by in corpus (12)

• Gamma-ray Emission of 60Fe and 26Al Radioactivities in our Galaxy
• The Positron Puzzle
• Imaging the 511 keV positron annihilation sky with COSI
• Galactic 26Al traces metal loss through hot chimneys
• Distribution and kinematics of 26Al in the Galactic disc
• Measurement of Galactic ${}^{26}$Al with the Compton Spectrometer and Imager
• Evolution of rotating massive stars with new hydrodynamic wind models
• Galactic Population Synthesis of Radioactive Nucleosynthesis Ejecta
• Formation and evolution of the local interstellar environment: combined constraints from nucleosynthetic and X-ray data
• The aluminium-26 distribution in a cosmological simulation of a Milky Way-type Galaxy
• Gamma-ray spectroscopy of galactic nucleosynthesis
• Measuring the smearing of the Galactic 511 keV signal: positron propagation or supernova kicks?