Comparing simulated Al-26 maps to gamma-ray measurements
Date
2019
Authors
Pleintinger, Moritz M. M.
Siegert, Thomas
Diehl, R
Fujimoto, Yusuke
Greiner, J
Krause, Martin G. H.
Krumholz, Mark
Journal Title
Journal ISSN
Volume Title
Publisher
European Southern Observatory (ESO)
Abstract
Context. The diffuse gamma-ray emission of 26Al 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. The morphology and dynamics of the interstellar medium are investigated in astrophysics through 3D hydrodynamic simulations in fine detail as there are few suitable astronomical probes available.
Aims. We aim to compare a galactic-scale hydrodynamic simulation of the Galaxy's interstellar medium, including feedback and nucleosynthesis, with gamma-ray data on 26Al 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 performed maximum likelihood fits of both simulated sky maps and observation-based maximum entropy maps to measurements using INTEGRAL/SPI. In order to study general morphological properties, we compare the scale heights of 26Al emission produced by the simulation to INTEGRAL/SPI measurements.
Results. The direct comparison shows that the simulation describes the observed inner Galaxy well, however it 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 prominent foreground emission sites which are not captured by the simulation.
Description
Keywords
Galaxy: structure, nuclear reactions, nucleosynthesis, abundances, ISM: bubbles, ISM: structure, galaxies: ISM, gamma rays: ISM
Citation
Collections
Source
Astronomy and Astrophysics
Type
Journal article
Book Title
Entity type
Access Statement
Open Access