franco_vazzaMay 5

#paperday on #astroph

"The Impact of the Magnetised Cosmic Web on Ultra High Energy Cosmic Ray Propagation" by Allegra Firinu, myself and Carmelo Evoli.

We investigated the role of realistic extragalactic magnetic fields in deflecting E>1e18eV cosmic rays, effectively creating "an horizon" beyond which particles cannot reach us, as they are trapped by magnetic fields.

https://arxiv.org/abs/2605.02324

#cosmoMAG #astrophysics #astronomy #physics

Show threadfranco_vazzaMay 5
The existence of a "Magnetic Horizon" has been surmised to make a sense of the strange sorting in composition of the highest energy UHECRs measured by the Pierre Auger Observatory, which is not predicted by standard acceleration models. But it could be explained if significant magnetic fields are affecting the propagation of 1e18eV particles more than of 1e20eV particles - which can happen because the deflection by magnetic fields scales as \propto E/B , where E=particle energy
Show threadfranco_vazzaMay 5
To study this process in detail, we used a set of realistic cosmological MHD simulations produced with the ENZO code, selected based on previous works comparing with radio observations, and featuring both a primordial field (0.3nG) and the seeding by feedback processes.
We analysed in sequence several snapshots from the same run, since UHECRs could have been injected in the ancient past.
Show threadfranco_vazzaMay 5

To be flexible in our analysis, we designed and deployed a new code, fully written in #Julia , which injects and transports UHECRs across redshift and starting from galaxies in the simulation, and also apply energy losses to them.

It can run in parallel and is publicly available here:

https://github.com/FrancoVazza/UMAREL_PUBLIC/

Show threadfranco_vazzaMay 5

The name is very important 😅
UMAREL=Ultra-high-energy cosmic rays in Magnetic fields Affected by Rigidity Diffusion and Energy Losses

Also, #Umarel is a word that only exists in the area of #Bologna , and it identifies retired males who stars at construction works in the street, typical with their arms behind their back.

https://en.wikipedia.org/wiki/Umarell

Show threadMike PeelMay 5
@franco_vazza @Wittylama that’s one of the Wikipedia articles you started, right?
Show threadLiam WyattMay 5
@mike_peel @franco_vazza yes! That’s so cool! I’m going to have to add that as a new footnote
Show threadfranco_vazzaMay 5
@Wittylama @mike_peel 😅 ok a good result of the article already
Show threadLiam Wyatt2d ago
@franco_vazza @mike_peel Returning to this... I know there is the ArchivX paper, but is there *any* independent publication that *specifically* mentions the reason for the acronym UMAREL? I would need that as a footnote to justify including this in the WP article. Even a blogpost will do.
Show threadfranco_vazza2d ago

@Wittylama @mike_peel 😅 not sure I understand...in this publication we introduced for the first time this code we wrote, and in the footnote within the article, we refer to the actual meaning, see figure.

We also created a github page where the connection is prominently explained (see bottom): https://github.com/FrancoVazza/UMAREL_PUBLIC/

franco_vazza2d ago
Show threadLiam Wyatt

@franco_vazza I've added it to the article now. See footnote 34.
What I mean is that: ideally, WP footnotes should always be "independent" descriptions of a thing, not the person saying it about themself (etc.)
So - if there is any independently published report *about* your work, that describes this umarel connection, that would be ideal.

meanwhile - art is imitating life and the WP article now references back to your paper ;-)

Jun 18 at 11:54amWeb
Show threadfranco_vazza2d ago
@Wittylama This is awesome, thanks!