Modelling Local Bubble analogs : synthetic dust polarization maps
Abstract
We present a study of synthetic observations of polarized dust emission at 353 GHz as seen by an observer within a cavity in the interstellar medium (ISM). The cavity is selected from a magnetohydrodynamic simulation of the local ISM with time-dependent chemistry, star formation, and stellar feedback in form of supernova explosions with physical properties comparable to the Local Bubble ones. We find that the local density enhancement together with the coherent magnetic field in the cavity walls makes the selected candidate a translucent polarization filter to the emission coming from beyond its domains. This underlines the importance of studying the Local Bubble in further detail. The magnetic field lines inferred from synthetic dust polarization data are qualitatively in agreement with the all-sky maps of polarized emission at 353 GHz from the Planck satellite in the latitudes interval 15° ≲ |b| ≲ 65°. As our numerical simulation allows us to track the galactic mid-plane only out to distances of pc, we exclude the region |b| ≲ 15° from our analysis. At large galactic latitudes, our model exhibits a high degree of small-scale structures. On the contrary, the observed polarization pattern around the Galactic Poles is relatively coherent and regular, and we argue that the global toroidal magnetic field of the Milky Way is important for explaining the data at |b| ≳ 65°. We show that from our synthetic polarization maps, it is difficult to distinguish between an open and a closed galactic cap using the inferred magnetic field morphology alone.
Citation
Maconi , E , Soler , J D , Reissl , S , Girichidis , P , Klessen , R S , Hennebelle , P , Molinari , S , Testi , L , Smith , R J , Sormani , M C , Teh , J W , Traficante , A & . 2023 , ' Modelling Local Bubble analogs : synthetic dust polarization maps ' , Monthly Notices of the Royal Astronomical Society , vol. 523 , no. 4 , pp. 5995–6010 . https://doi.org/10.1093/mnras/stad1854
Publication
Monthly Notices of the Royal Astronomical Society
Status
Peer reviewed
ISSN
0035-8711Type
Journal article
Description
Funding: JDS, PG, and RSK acknowledge funding from the European Research Council (ERC) via the synergy grant ‘ECOGAL – Understanding our Galactic ecosystem: From the disc of the Milky Way to the formation sites of stars and planets’ (project ID 855130). RSK and SR acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG) via the Collaborative Research Center (SFB 881, project ID 138713538) ‘The Milky Way System’ (subprojects A1, B1, B2, and B8) and from the Heidelberg Cluster of Excellence (EXC 2181-390900948) ‘STRUCTURES: A unifying approach to emergent phenomena in the physical world, mathematics, and complex data’, funded by the German Excellence Strategy. RSK also thanks the German Ministry for Economic Affairs and Climate Action for funding in the project ‘MAINN – Machine learning in astronomy: understanding the physics of stellar birth with invertible neural networks’ (funding ID 50OO2206). MCS acknowledges financial support from the Royal Society (URF\R1\221118).Collections
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