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master-thesis-presentation/talking_points.md
2025-09-18 00:02:13 +02:00

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# Comments for the presentation
## Introduction
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// COMMENTS:
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// Explanation
- further modulation by _RSD_
// From first principles
// small scales to resolve sources + sinks + feedback
// large scales to capture statistics
// IF ASKED: difference with `21cmFAST`:
// based on excursion formalistm -> only valid >= 1Mpc, which is ideal for large volumes + statistics => 21-cm forecasts
// interesting to build emulators for instance
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// From the xray emission
// primordial + heating term
// expansion + deposition by xrays
// => xrays are assumed to be the only source of heating
// $
// x_("HII")(r bar M, z) = theta_"H" lr([R_b (M, z) - r], size: #150%)
// $
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// COMMENTS:
// - contribution from the lyman lines
// - 1/r^2 decrease from spreading photons
// - more steep outwards + sharp drop due to redshifting out of line
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== Revisiting the 21cm signal
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### Procedure
Painting using all halos that match in a SINGLE step
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OVERLAP EXPLICITLY ALLOWED
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### Postprocessing
- ionization overlaps
- corrections due to RSD
- computation of derived quantities
- summary statistics
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### Maps
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### Signal
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## Halo growth
### Motivation
### Effect on the flux profiles
// COMMENTS
// That will be directly affect the global signal as well
// shifting
//
// Yu-Siu already investigated the more nuanced effect of stochasticity but the approach we propose should supersede that
### Inferring growth from #smallcaps[Thesan] data
// ideal for rapid iterations
// in a parallelized fashion => want to stay fast
// fix the original mass for max. consistency
// fix the allowed dynamic range
// this sort of "breaks the degeneracy" between halos of the same mass but different growth histories
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RESULT OF LOADING:
// COMMENTS:
// no clear trend between mass and growth rate
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## Adaptations
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### Central changes
// important since the bins are more now
// largely through vectorization -> still "native" python
// usage of HDF5
// solid caching mechanisms -> resume simulations, etc...
### Simplified usage
In a page or less
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## Results
### Map outputs
// the ones where the accretion rate is likely higher
// in particular: no values where the coupling has become weaker
// will become apparent in the signal as well
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// those are the ones where the diff vanishes: e.g. top right
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// more variation due to the different accretion rates
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// Globally:
// more dynamic range while the mean systematically shifts towards the (biased) lower accretion rates
// Intermezzo - compare with lower alpha range - mostly similar but occasional contributions from higher alpha values
// => recommend keeping a wide range since it does not affect performance (if the bins are empty anyway)
// the more intersting discussion to be had is the effect of a more fine binning - thesan data already gives an indication which values will be most frequent
// => the implementation to test that is there
// the halos themselves produce a stronger singal while the background is usually
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### Signals
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## Conclusion
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### Summary
// since it affects the SFR and thus the emissivity
// change in profiles trivially
// which could in theory be absorbed by shifting other paremeters
// which we can hope to observe (although many are subtle)
// unique position of 21-cm cosmology -> cannot discuss observational constraints
// invite you to check out
### Outlook
// finally ready for direct comparison with c2ray? now that parameters and loading have been properly implemented
// Assuming other relations related to production of photons is (hopefully by now well motivated) complex
// these cannot directly be inferred => expressed as a distribution as a function of another halo property
// the scale-up -> large volumes with usable merger trees
// comitting to reserving some 100s of node hours (which I would still quantify as fast)