franco_vazza

#SimulatedUniverses #AstroPhysicsFactlet
Professor in #Astrophysics at the University of Bologna and former #ERC grantee.
I study the cosmic web, extragalactic magnetism and clusters of galaxies with colorful simulations.
Less #AI and more tiramisu in our lives!

https://cosmosimfrazza.eu
#science #physics #astronomy #COSMOMAG

website: https://cosmosimfrazza.eu
country: Italy
TedX: https://youtu.be/Lgo-TLMMmGI
In the media: https://frontiers.altmetric.com/details/91389862

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Last Notes

2026-05-26 10:23:28 GMT

Tomography of a simulated cluster of galaxies with the eulerian Enzo code, covering about 2 Megaparsec along the line of sight, slice by slice (each slice being 4kpc deep).
Many many substructures, mostly filamentary and mostly driven by B-fields on small scales (<10-100kpc). This assumes an ideal MHD picture for the intracluster medium, while we know well it is a weakly collisional plasma, yet this structures at these scales might be realistic 🤞🏼
#SimulatedUniverses #astrophysics #science
https://files.mastodon.social/media_attachments/files/116/640/373/037/428/251/original/5bf1e240a414e9f5.mp4

2026-05-14 14:42:43 GMT

Today is a good day for me as #physics professor because I made a final experiment working in the class, a simple yet seminal one (by Michael Faraday, 1831!) which I so far replicated only in partial ways.
It gave the theoretical basis for our modern technology, from power generators to the wifi transmission of power and signals (i.e. telecommunications).
Let me show it 3 steps:
1. The #Faraday induction I usually show: a moving strong magnets induces a tiny tension in a secondary coil.
https://files.mastodon.social/media_attachments/files/116/573/431/955/194/785/original/78c9a6fec4fac6af.mp4

2026-04-24 09:47:46 GMT

***PLEASE SPREAD IF YOU CAN***
my Physics & Astro department in Bologna (Italy) just opened a call
for 2 contracts for 1 year (24kE) for young researchers from #Palestine:
https://bandi.unibo.it/ricerca/incarichi-di-ricerca?id_bando=162
https://ricercatm.unibo.it/incarichiricerca_segretari/_bandi/2008/ProceduraSelettiva162[227]TutorColloquio_eng.htm
Deadline: 15/06/2026
Eligibility: young scholars in Physics/Geo/Astro citizens of Palestine, refugees from Palestine, refugees residing in Palestine, or holders of a permanent residence permit or international protection in Palestine
#physics #science #astrophysics

2026-04-20 07:28:20 GMT

the joy of receiving applications to my post-doc which are visibly and 100% generated using #AI (which btw takes 2 second to notice, if you are expert, as for example it generated references to unexisting works of mine ). seriously, junior people in #academia hear me out: do not underestimate how dramatically bad this looks like, and wipes out even the smallest chance of you being retained as a backup candidate (in case the first ones will decline).
😩
#astronomy #astrophysics #science

2026-03-19 16:17:19 GMT

Here is the "experiment" of today in the #Electromagnetism class: a tiny replica of the Leiden jar which is a far ancestor of the battery, consisting of a distribution of chargers trapped in in a glass container, which acts as a capacitor when the inner and outer conducting layers are reconnected again.
I used a voltmeter to detect the tiny residual voltage (0.4mV) produced across the bottle after the charging process.
#science #physics
https://files.mastodon.social/media_attachments/files/116/256/728/487/768/592/original/6b1758db5ca94e3c.mp4

2025-12-05 07:25:50 GMT

A somewhat stereotypical and weird interaction I have now seen several time with several people:
Them: "I and my collaborators like your project/idea/code, could you privately share all details with us please?"
Me: "Ok, that might work, but can you tell me a bit more about what you want to do with it?"
Them: "No way, you need to sign a non-disclosure-agreement with us first".
😱 😱 😱 😱 😱
Anyone else...?
#Academia #astrophysics #science

2025-11-14 12:45:59 GMT

Stupid me and stupid italian #newspapers: this morning i texted my collaborator in #Kyiv to ask for a zoom call at lunch time - and only quite later i discovered, scrolling down the main page of italian newspapers, about the latest criminal rocketing of the capital.
But of course, it was more important to put upfront in the news italian football and the approaching davis cup...
😩
#Ukraine #academia

2025-11-01 08:42:51 GMT

My wonderful colleagues at the department of #Maths at the University of #Bologna managed to open a call for 2 scholarships (10kE each) for students from #Gaza to relocate to Italy. Students can apply just after enrolling online to a single exam, which is cost-free and easy to do.
It's a drop in the ocean, which still required some bureaucratic magic by them. We hope to soon follow also from other Departments (including mine)
link here:
https://bandi.unibo.it/s/mat/department-of-mathematics-2-scholarships-in-favor-of-students-from-the-gaza-strip
#academia #science #Palestine
https://files.mastodon.social/media_attachments/files/115/473/544/139/369/878/original/a91363aa950c1889.png

2025-10-03 09:49:48 GMT

Another massive #strike in #Bologna and in #Italy today.
Called only yesterday, it has unclear objectives, it combines many themes and is also against this government.
It is more emotional then rational, it mixes so much discontents and it's a reaction to the feeling of helplessness about what governments allow to happen before our eyes.
That's why I 100% felt like participating, and for the first time I did together with my 11yr old son. 🫠
#scioperogenerale #Flottilla #sciopero
https://files.mastodon.social/media_attachments/files/115/309/579/977/539/049/original/fa1e7401835f6b9d.jpg
https://files.mastodon.social/media_attachments/files/115/309/580/022/263/013/original/1dc1b872cbea72ac.jpg
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https://files.mastodon.social/media_attachments/files/115/309/606/643/796/934/original/dcb8f881874e94dd.jpg

2025-09-22 06:59:05 GMT

For the first time today, I am officially on strike (how do #university professors formally strike? I had to look it up...) joining the national general #strike in #Italy against the massacre in #Gaza , the continuous threatening of life conditions and land grabbing in the West Bank, and in solidarity with the Global Sumud #Flotilla
Will this obtain anything?
I strongly doubt it...but the minimal bar is that our government (and my University too) take notice and can become bolder.
#sciopero
https://files.mastodon.social/media_attachments/files/115/246/647/682/191/561/original/06f4a4e61ce0cd61.png
https://files.mastodon.social/media_attachments/files/115/246/649/065/270/687/original/bed8dd899bb7c623.jpg

2025-09-03 08:42:58 GMT

I find it annoying to keep seeing here post which likely are generated from within #bluesky which requires me to sign up after clicking on them.
How are people dealing with this?
Do you all have by now another mirror account on bluesky? Am I the only one here on mastodon, speaking with mirrors and avatars? 😅
Probably not. But I keep seeing "pressure" towards bluesky.
However, I like it here so far, like some remote beach with few people...
#academia #astronomy #science

2025-08-14 07:48:45 GMT

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C) a 3D rendering of cosmic rays propagating away from their initial assumed locations (within galaxies) , with slightly different modalities depending on whether they cross other halos, filaments or voids
https://files.mastodon.social/media_attachments/files/115/026/009/986/527/322/original/c8bc863d74e469f7.mp4

2025-08-14 07:45:16 GMT

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B) the same protons, but with an initial lower energy (0.01J). A lower energy means a proportionally smaller gyration radius around magnetic field lines, hence more tangled trajectories
https://files.mastodon.social/media_attachments/files/115/026/002/084/938/629/original/40790f89ee83fe28.mp4

2025-08-14 07:42:58 GMT

In order to advance our understanding of the unknown sources of ultra high energy cosmic rays (the most energetic particles in space, propagating with a kinetic energy up to a few Joules, i.e. a single particle can carry the energy of an entire fast tennis ball) we need to model their deflection by intergalactic magnetic fields 🧲. Here a collection of a few #simulations.
A) protons of 1J crossing our most realistic magnetic field model #astronomy #science #physics
https://files.mastodon.social/media_attachments/files/115/025/993/032/023/422/original/f814cc090f0f5658.mp4

2025-08-12 08:27:29 GMT

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If the service would be available in Italy too, I would like to have a two meters long reproduction of a tray of tiramisu

2025-08-12 08:25:40 GMT

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fascinating thread

2025-08-08 12:41:24 GMT

Forming an army of resistants, one at a time
https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2025.1561873/full
#SimulatedUniverses
https://files.mastodon.social/media_attachments/files/114/993/177/122/774/002/original/569d3ea2bcdbd5ee.jpg

2025-08-07 11:49:23 GMT

A few thoughts about modern #museum for #science, after I visited a few in the last months
(e.g. https://mastodon.social/@franco_vazza/114438970133673779
https://mastodon.social/@franco_vazza/114965935128090992
https://mastodon.social/@franco_vazza/114983548716611231
)
Curious to know what other people here think about this.
Modern #museums are really captivating, and children (at least in the 5-10 years of age I directly tested) generally love them, at least for the first hour or so.
They are dynamics, the spaces are inviting, all is elegant and "cool".
https://files.mastodon.social/media_attachments/files/114/987/321/030/665/310/original/9106260a216af012.jpg

2025-06-05 07:16:36 GMT

Please don't tell me anymore what astrophysicists do is pointless - according to this very serious article we just discovered not less than GOD - and by the way nor me neither my coauthor noticed so far, since our article is from 2021.
Not bad, anyway, have to put this in the CV.
That's the God discovery paper btw: https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2020.525731/full
I myself have to re-read it as I missed that part!
#astronomy #astrophysics #science
https://files.mastodon.social/media_attachments/files/114/629/527/361/710/017/original/6f94ee1165d5205e.png

2025-05-24 11:00:45 GMT

Similar to this:
https://mastodon.social/@franco_vazza/114551656962929541
but it's the top view.
Magnet free-falling through a copper cylinder is braked by the magnetic braking effect: induced Foucault currents on the surface of cylinder (vai Faraday law) induce magnetic fields, which push the magnet upwards and slow down the push of gravity.
#astrodon #science #physics #astronomy
https://files.mastodon.social/media_attachments/files/114/562/454/330/813/086/original/0f9ad8576708efd5.mp4

2025-05-22 13:12:50 GMT

A classical #electromagnetism experiment in this time of the year (i.e. towards the end of my EM course): magnetic breaking acting on a falling magnet (home version).
The left magnet just falls in free fall, the right one gets braked by the induced magnetic field within the aluminum cylinder (mad just sticking together three aluminum foil wraps for kitchen use).
Where is the induced magnetic field coming from? From #Faraday's induction law of course!
#science #physics #astronomy
https://files.mastodon.social/media_attachments/files/114/551/652/373/987/925/original/d03c1f67bcc8fc92.mp4

2025-05-15 13:32:46 GMT

#Magnetism in #physics
you might be familiar with "permanent" magnets (like fridge magnets) or materials which are not permanently magnetised, but can react to external magnetic fields (like iron).
Do you know that even apparently un-magnetised matter, like water, reacts to external magnetic fields?
Here is the experiment I did today in class:
a permanent magnet can (very slowly, the movie is x2 accelerated) push water away!
#science #astrodon
https://files.mastodon.social/media_attachments/files/114/512/096/259/165/043/original/a51945173074ed4b.mp4

2025-04-28 16:58:10 GMT

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🤮 @npub1zxn…0kqm @npub1qj0…wryw

2025-04-14 08:44:09 GMT

#paperday Want to start the week with a fresh paper which clearly thinks outside of the box? 😅
Here you go
https://arxiv.org/abs/2504.08461
"Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulation"
Will do a paper explainer in the near future...
#astrodon #astronomy #science #physics #SimulatedUniverses #SimulationHypothesis
https://files.mastodon.social/media_attachments/files/114/335/425/733/030/061/original/aea717f8e21409d2.png

2025-02-24 15:50:29 GMT

To give a single measure of how much #dystopian this time is, I find myself cheering and almost feeling proud at the fact that italian PM, Giorgia Meloni (far right, sympathising for neofascist and so evil in many ways) stated the simple fact that
** #Ukraine was brutally aggressed**
while remotely speaking at some non sense MAGA event in the US.
(extra points for getting caught a few seconds after the end of the speech to say "I wanna die"). I'm praying she keeps standing by that.

2025-02-19 07:08:09 GMT

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Small correction of italian cities: it's 3 on the Torino scale and -0.18 on the Palermo scale, whatever this means

2025-02-14 18:14:24 GMT

It's a wrap!
Interesting 4 days in Trieste, small meeting with people looking for possible signatures of primordial magnetic fields in their very different sets of observations :
- Gravitational waves (z=10^12 ?)
- the cosmic microwave background (z=1000)
- the Lyα forrest (z=6)
-Faraday Rotation from extragalactic sources (z<3)
- Blazars (z<0.1)
Independently, many are getting convinced they might be there.
Present uncertainty: 1e-15G <B<1e-10 G
#astronomy #science #astrodon
https://files.mastodon.social/media_attachments/files/114/003/597/989/163/391/original/6a752225adc57e9d.png

2025-01-27 13:12:52 GMT

Just a normal day in discussing theory of magnetic field evolution in the early Universe with colleagues
#astronomy #science
https://files.mastodon.social/media_attachments/files/113/900/489/247/151/301/original/30d1a680043918eb.png

2025-01-22 09:10:44 GMT

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of course!

2024-12-28 13:52:25 GMT

A nice view of the canal in #Padova, towards the specola (where I graduated ages ago) . #photography
https://files.mastodon.social/media_attachments/files/113/730/774/235/729/310/original/b6859be31edc7a5b.jpg

2024-12-08 15:49:50 GMT

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Sunset over my desk is not bad either
https://files.mastodon.social/media_attachments/files/113/617/992/250/294/480/original/3dd49878da966111.jpg
https://files.mastodon.social/media_attachments/files/113/617/992/679/594/597/original/c081bc18c0e149dc.jpg
https://files.mastodon.social/media_attachments/files/113/617/992/940/813/985/original/a7a24b7eb56a000b.jpg

2024-12-08 12:18:58 GMT

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Worse and worse
https://files.mastodon.social/media_attachments/files/113/617/161/349/505/362/original/86bdd1c3891ff62f.jpg
https://files.mastodon.social/media_attachments/files/113/617/163/692/975/687/original/7562ffced5b1a979.jpg

2024-12-08 11:41:47 GMT

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Awful
https://files.mastodon.social/media_attachments/files/113/617/017/322/114/828/original/4d5fd9a0e797473d.jpg

2024-12-08 11:18:20 GMT

Back in my favourite and most productive office! (it's Sunday, ok, I know..) #academia #astrodon
https://files.mastodon.social/media_attachments/files/113/616/922/027/998/408/original/5531ba325855bc64.jpg

2024-11-20 17:13:29 GMT

That's the inside of the Virgo gravitational wave detectors in Pisa. It looks like a 3.5km long metal pipe, and it basically is, but together with Ligo in the US it detected a displacement of order 1e-18 meters due to the passage of gravitational waves from colliding black holes and it opened a whole new era in #astronomy #science
https://files.mastodon.social/media_attachments/files/113/516/388/120/820/925/original/9bfaafd3b60deb1b.jpg
https://files.mastodon.social/media_attachments/files/113/516/389/001/133/378/original/9c9ff26030bd2672.jpg
https://files.mastodon.social/media_attachments/files/113/516/389/411/025/351/original/212a6a6f75c3ce24.jpg
https://files.mastodon.social/media_attachments/files/113/516/389/727/528/151/original/5e1638228820ade8.jpg

2024-11-18 17:23:03 GMT

If you are bored of using the same #hotels that look like the same everywhere, and you end up in #Pisa, I have a recommendation for you:
First reaction: shock 😱 - I just wanted a normal hotel.
Second reaction: I realised I booked by chance in the most ancient Hotel of Italy, so they actually want to preserve it as it was at the end of 1800s.
Third reaction: by chance I got the room used by Charles #Dickens 😱 😱 😱 😱
https://www.royalvictoria.it/411-camera-charles-dickens/
#academic
https://files.mastodon.social/media_attachments/files/113/505/107/590/656/170/original/b06d70e29ddd8f26.jpg
https://files.mastodon.social/media_attachments/files/113/505/107/604/347/266/original/16590816cefe0fa1.jpg
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2024-10-21 12:20:55 GMT

The first 256 antennas of the Low-frequency part of the #SKA are there in 🤩
(movie via https://www.skao.int/en/explore/construction-journey)
Also in the same website, you can see the synchronisation dance of the SKA - MID (high frequency part of SKA) with MeerKAT dishes, in South Africa.
#astronomy #astrodon #science
https://files.mastodon.social/media_attachments/files/113/345/365/473/278/015/original/61768c156c1832a9.mp4

2024-10-19 14:15:15 GMT

Simulated small-scale dynamo turbulence in a volume of ~100kpc^3, with a numerical Reynolds number of about ~1e3 and stationary subsonic forcing, using ENZO-MHD.
Something like this - if plasmas were just a simple fluid on all scales, which they are not - should be happening also in the #space inbetween galaxies, over scales of several hundreds million years.
#astronomy #astrodon #SimulatedUniverses
https://files.mastodon.social/media_attachments/files/113/334/496/691/340/420/original/8b9273f9a4717d50.mp4

2024-10-14 12:26:10 GMT

Thread on international conferences, remote attending etc...
So for the first time ever I was invited in the SOC (=Scientific Organising Committee) of a conference abroad.
Before joining, I made clear that a prerequisite for me was that a minimum amount of remote attendees/speakers should be allowed: we cannot go fully back to pre-covid.
I was reassured and so was happy to serve in the past months by setting up the program, deciding speakers etc.
Sadly...
#astrodon #astronomy #science

2024-09-23 14:28:34 GMT

Last slide of my talk at this remote conference organised by the observatory in Lviv
https://mastodon.social/@franco_vazza/113185411200835301
#astrodon #astronomy #science
https://files.mastodon.social/media_attachments/files/113/187/336/444/743/014/original/ada8d3354e6c81b1.png

2024-09-21 11:53:12 GMT

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the lack of influencers (both in my field, #astronomy, or in general) is a strong reason for me to have chosen mastodon and to stay here! 👍

2024-08-26 09:12:05 GMT

I resumed working and a good way to start is to praise my youngest collaborators who got their papers accepted in the last months.
First: Chiara Stuardi at IRA/INAF in Bologna, with
"Radio U-Net: a convolutional neural network to detect diffuse radio sources in galaxy clusters and beyond"
https://arxiv.org/abs/2408.10871
(Stuardi, Gheller, Vazza & Botteon)
It introduces a fully convolutional neural network to identify diffuse radio emission in radio data.
#paperday #astronomy #astrodon #science
https://files.mastodon.social/media_attachments/files/113/027/544/527/122/755/original/fc2e6f5183090965.png

2024-08-12 19:12:58 GMT

I am not doing any new #AstroPhysicsFactlet since a while...they took quite some work and effort!
Howvever, given the time of the year it seems in order to re-up this one
https://mastodon.social/@franco_vazza/110933328697681202
which concerned waves in a pool and the formation of the cosmic web!
#astrodon #astronomy #physics
https://files.mastodon.social/media_attachments/files/112/950/637/565/862/504/original/2a11638a2eb9b470.jpg
https://files.mastodon.social/media_attachments/files/112/950/638/493/760/317/original/2f83f5299d47413a.jpg

2024-08-10 07:52:42 GMT

Portable turbulent device to keep Kolmogorov with you everywhere!
(credits to the creator below 👇)
#physics #astrodon #astronomy #turbulence
https://files.mastodon.social/media_attachments/files/112/936/627/936/847/518/original/3ff6ec23bf51183e.mp4