Driving galactic winds with magnetic fields at low and high redshift. (arXiv:2012.12905v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Steinwandel_U/0/1/0/all/0/1">Ulrich P. Steinwandel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dolag_K/0/1/0/all/0/1">Klaus Dolag</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lesch_H/0/1/0/all/0/1">Harald Lesch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Burkert_A/0/1/0/all/0/1">Andreas Burkert</a>
Although playing a key role for our understanding of the evolution of
galaxies, the exact way how observed galactic outflows are driven is still far
from being understood and therefore our understanding of associated feedback
mechanisms that control the evolution of galaxies is still plagued by many
enigmas. In this work we present a simple toy model that can provide insight on
how non-axis-symmetric instabilities in galaxies (bars, spiral-arms, warps) can
lead to local exponential magnetic field growth by a radial flows beyond the
equipartition value by at least two orders of magnitude on a time-scale of a
few $100$ Myr. Our predictions show that the process can lead to galactic
outflows in barred spiral galaxies with a mass loading factor $eta approx
0.1$, in agreement with our numerical simulations. Moreover, our outflow
mechanism could contribute to an understanding of the large fraction of bared
spiral galaxies that show signs of galactic outflows in the CHANG-ES survey.
Extending our model shows the importance of such processes in high redshift
galaxies by assuming equipartition between magnetic energy and turbulent
energy. Simple estimates for the star formation rate (SFR) in our model
together with cross-correlated masses from the star-forming main-sequence at
redshifts $zsim2$ allow us to estimate the outflow rate and mass loading
factors by non-axis-symmetric instabilities and a subsequent radial inflow
dynamo, giving mass loading factors of $eta approx 0.1$ for galaxies in the
range of M$_{star}=10^9 – 10^{12}$ M$_{odot}$, in good agreement with recent
results of Sinfoni and KMOS$^{3mathrm{D}}$.
Although playing a key role for our understanding of the evolution of
galaxies, the exact way how observed galactic outflows are driven is still far
from being understood and therefore our understanding of associated feedback
mechanisms that control the evolution of galaxies is still plagued by many
enigmas. In this work we present a simple toy model that can provide insight on
how non-axis-symmetric instabilities in galaxies (bars, spiral-arms, warps) can
lead to local exponential magnetic field growth by a radial flows beyond the
equipartition value by at least two orders of magnitude on a time-scale of a
few $100$ Myr. Our predictions show that the process can lead to galactic
outflows in barred spiral galaxies with a mass loading factor $eta approx
0.1$, in agreement with our numerical simulations. Moreover, our outflow
mechanism could contribute to an understanding of the large fraction of bared
spiral galaxies that show signs of galactic outflows in the CHANG-ES survey.
Extending our model shows the importance of such processes in high redshift
galaxies by assuming equipartition between magnetic energy and turbulent
energy. Simple estimates for the star formation rate (SFR) in our model
together with cross-correlated masses from the star-forming main-sequence at
redshifts $zsim2$ allow us to estimate the outflow rate and mass loading
factors by non-axis-symmetric instabilities and a subsequent radial inflow
dynamo, giving mass loading factors of $eta approx 0.1$ for galaxies in the
range of M$_{star}=10^9 – 10^{12}$ M$_{odot}$, in good agreement with recent
results of Sinfoni and KMOS$^{3mathrm{D}}$.
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