The imprint of magnetic fields on absorption spectra from circumgalactic wind-cloud systems

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Hauptverfasser: Casavecchia, Benedetta, Banda-Barragan, Wladimir, Brueggen, Marcus, Brighenti, Fabrizio, Scannapieco, Evan
Format: Preprint
Veröffentlicht: 2024
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author Casavecchia, Benedetta
Banda-Barragan, Wladimir
Brueggen, Marcus
Brighenti, Fabrizio
Scannapieco, Evan
author_facet Casavecchia, Benedetta
Banda-Barragan, Wladimir
Brueggen, Marcus
Brighenti, Fabrizio
Scannapieco, Evan
contents Galactic winds probe how stellar feedback regulates the mass and metallicity of galaxies. Observations show that galactic winds are multiphase and magnetised. In the local Universe, the dense phase is traced by emission and absorption lines, which reveal the presence of fast-moving clouds embedded in hot streams. Simulations tell us that magnetic fields can shield such clouds and delay their disruption, but there is little discussed on their observational effects. Using 3D MHD simulations, we study the influence of two orientations of the magnetic field (aligned and transverse) on the cloud morphology, temperature and density structure, mixing fraction, ion kinematics, column densities, and absorption spectra. We study supersonic wind-cloud systems with radiative processes, and develop a framework to extract ion column density maps and synthetic absorption spectra. The framework relies on studying ion populations and creating down-the-barrel spectra via an interface that links our PLUTO simulations to TRIDENT using YT, CLOUDY, and STARBURST99. We find that the transverse magnetic field makes the cloud asymmetric, shields and protects dense cold gas, and reduces mixing fractions compared to the aligned case. Ions can reach higher velocities in the transverse field case. The imprints of the initial orientation of the field on the synthetic spectra are: in the cold phase we find no signature of C ii and Si ii when the field is aligned, in the intermediate phase traced by C iv and Si iv we find broader lines in the transverse case, and in the warm phase we find deeper lines for O vi and N v in the aligned case, but they are less sensitive to the field orientation. Magnetic fields significantly affect the absorption spectra of cold clouds. Intermediate ions are the most sensitive to the magnetic field orientation and can potentially yield information about magnetic field topology.
format Preprint
id arxiv_https___arxiv_org_abs_2402_01475
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The imprint of magnetic fields on absorption spectra from circumgalactic wind-cloud systems
Casavecchia, Benedetta
Banda-Barragan, Wladimir
Brueggen, Marcus
Brighenti, Fabrizio
Scannapieco, Evan
Astrophysics of Galaxies
Galactic winds probe how stellar feedback regulates the mass and metallicity of galaxies. Observations show that galactic winds are multiphase and magnetised. In the local Universe, the dense phase is traced by emission and absorption lines, which reveal the presence of fast-moving clouds embedded in hot streams. Simulations tell us that magnetic fields can shield such clouds and delay their disruption, but there is little discussed on their observational effects. Using 3D MHD simulations, we study the influence of two orientations of the magnetic field (aligned and transverse) on the cloud morphology, temperature and density structure, mixing fraction, ion kinematics, column densities, and absorption spectra. We study supersonic wind-cloud systems with radiative processes, and develop a framework to extract ion column density maps and synthetic absorption spectra. The framework relies on studying ion populations and creating down-the-barrel spectra via an interface that links our PLUTO simulations to TRIDENT using YT, CLOUDY, and STARBURST99. We find that the transverse magnetic field makes the cloud asymmetric, shields and protects dense cold gas, and reduces mixing fractions compared to the aligned case. Ions can reach higher velocities in the transverse field case. The imprints of the initial orientation of the field on the synthetic spectra are: in the cold phase we find no signature of C ii and Si ii when the field is aligned, in the intermediate phase traced by C iv and Si iv we find broader lines in the transverse case, and in the warm phase we find deeper lines for O vi and N v in the aligned case, but they are less sensitive to the field orientation. Magnetic fields significantly affect the absorption spectra of cold clouds. Intermediate ions are the most sensitive to the magnetic field orientation and can potentially yield information about magnetic field topology.
title The imprint of magnetic fields on absorption spectra from circumgalactic wind-cloud systems
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2402.01475