The Fermi and eROSITA bubbles likely result from identical ~10^56 erg collimated outbursts separated by ~10 Myr, with asymmetry indicating an eastern ambient density gradient.
Fermi bubble edges: spectrum and diffusion function
2 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
Current measurements of the $\gamma$-ray Fermi bubbles (FB) are based on model-dependent tracers, carry substantial systematic uncertainties, and are at some tension with each other. We show that gradient filters pick out the FB edges, which are found to smoothly connect to the bipolar X-ray structure emanating from the Galactic center, thus supporting the interpretation of the FBs as a Galactic-scale phenomenon. The sharp edges facilitate a direct, model-free measurement of the peripheral FB spectrum. The result is strikingly similar to the full FB-integrated spectrum, softened by a power law of index $\eta\simeq (0.2\mbox{--}0.3)$. This is naturally explained, in both hadronic and leptonic models, if cosmic rays are injected at the edge, and diffuse away preferentially at higher energies $E$. The inferred, averaged diffusion function in the (more plausible) leptonic model, $D(E)\simeq 10^{29.5}(E/10\mbox{ GeV})^{0.48\pm0.02}\mbox{ cm}^2\mbox{ s}^{-1}$, is consistent with estimates for Kraichnan-like turbulence. Our results, in particular the minute spatial variations in $\eta$, indicate that the FB edge is a strong, Mach $\gtrsim5$, forward shock.
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astro-ph.HE 2verdicts
UNVERDICTED 2representative citing papers
Reports ~20% projected polarization in synchrotron and thermal dust emission from Fermi bubbles, with fields parallel to edges, and attributes larger lobes to an older supermassive black hole outburst.
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Nested Fermi and eROSITA bubbles require very similar $\sim10^{56}$ erg collimated Galactic-center outbursts; their asymmetry indicates an eastern density gradient
The Fermi and eROSITA bubbles likely result from identical ~10^56 erg collimated outbursts separated by ~10 Myr, with asymmetry indicating an eastern ambient density gradient.
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Detection of polarized Fermi-bubble synchrotron and dust emission
Reports ~20% projected polarization in synchrotron and thermal dust emission from Fermi bubbles, with fields parallel to edges, and attributes larger lobes to an older supermassive black hole outburst.