Misaligned jets from Sgr A$^*$ and the origin of Fermi/eROSITA bubbles. (arXiv:2211.12967v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Sarkar_K/0/1/0/all/0/1">Kartick C. Sarkar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mondal_S/0/1/0/all/0/1">Santanu Mondal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sharma_P/0/1/0/all/0/1">Prateek Sharma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Piran_T/0/1/0/all/0/1">Tsvi Piran</a>
One of the leading explanations for the origin of Fermi Bubbles is a past jet
activity in the Galactic center supermassive black hole Sgr A$^*$. The claimed
jets are often assumed to be perpendicular to the Galactic plane. Motivated by
the orientation of pc-scale nuclear stellar disk and gas streams, and a low
inclination of the accretion disk around Sgr A$^*$ inferred by the Event
Horizon Telescope, we perform hydrodynamical simulations of nuclear jets
significantly tilted relative to the Galactic rotation axis. The observed
axisymmetry and hemisymmetry (north-south symmetry) of Fermi/eROSITA bubbles
(FEBs) due to quasi-steady jets in Sgr A$^*$ can be produced if the jet had a
super-Eddington power ($gtrsim 5times 10^{44}$ erg s$^{-1}$) for a short time
(jet active period $lesssim 6$ kyr) for a reasonable jet opening angle
($lesssim 10^circ$). Such powerful explosions are, however, incompatible with
the observed O VIII/O VII line ratio towards the bubbles, even after
considering electron-proton temperature non-equilibrium. We argue that the only
remaining options for producing FEBs are i) a low-luminosity ($approx
10^{40.5-41}$ erg s$^{-1}$)) magnetically dominated jet or accretion wind from
the Sgr A$^*$, and ii) a SNe or TDE driven wind of a similar luminosity from
the Galactic center.
One of the leading explanations for the origin of Fermi Bubbles is a past jet
activity in the Galactic center supermassive black hole Sgr A$^*$. The claimed
jets are often assumed to be perpendicular to the Galactic plane. Motivated by
the orientation of pc-scale nuclear stellar disk and gas streams, and a low
inclination of the accretion disk around Sgr A$^*$ inferred by the Event
Horizon Telescope, we perform hydrodynamical simulations of nuclear jets
significantly tilted relative to the Galactic rotation axis. The observed
axisymmetry and hemisymmetry (north-south symmetry) of Fermi/eROSITA bubbles
(FEBs) due to quasi-steady jets in Sgr A$^*$ can be produced if the jet had a
super-Eddington power ($gtrsim 5times 10^{44}$ erg s$^{-1}$) for a short time
(jet active period $lesssim 6$ kyr) for a reasonable jet opening angle
($lesssim 10^circ$). Such powerful explosions are, however, incompatible with
the observed O VIII/O VII line ratio towards the bubbles, even after
considering electron-proton temperature non-equilibrium. We argue that the only
remaining options for producing FEBs are i) a low-luminosity ($approx
10^{40.5-41}$ erg s$^{-1}$)) magnetically dominated jet or accretion wind from
the Sgr A$^*$, and ii) a SNe or TDE driven wind of a similar luminosity from
the Galactic center.
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