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Marcel S. Pawlowski

@8minutesold.bsky.social

450 followers 350 following 390 posts

Astrophysicist studying cosmic choreographies of dwarf galaxies. Junior Research Group Leader at AIP, Street Photographer (he/him) Autor des Buchs „Von tanzenden Galaxien, Dunkler Materie, und anderen kosmischen Rätseln“ Potsdam, Germany

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Marcel S. Pawlowski @8minutesold.bsky.social · Nov 19

Es ist soweit: heute erscheint mein Sachbuch "Von Tanzenden Galaxien, Dunkler Materie und anderen kosmischen Rätseln" ISBN: 978-3-95972-788-4

Auf 304 Seiten schreibe ich über Astronomie, Galaxien, und wie Astrophysiker*innen Herausforderungen des Dunkle-Materie-Modells begegnen. 🔭🧪

Titelblatt des Astronmie-Sachbuchs Buchs "Von tanzenden Galaxien, Dunkler Materie, und anderen kosmischen Rätseln", von Marcel S. Pawlowski. Es zeigt den Titel sowie als Hintergrundbild eine Aufnahme der interagierenden Kaulquappen-Galaxie mit einem langen Gezeitenarm.

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Marcel S. Pawlowski @8minutesold.bsky.social · 9h

And now on to the more demanding part of this trip, getting to Chiang Mai in Thailand to give a lecture for the WE-Heraeus and NARIT Cosmology School. First leg is a train trip to Madrid, then flights to Doha and Bangkok. If all goes according to plan, it’ll take me 31 hours door to door.

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Marcel S. Pawlowski @8minutesold.bsky.social · 10h

After an intense IAU Symposium on galaxy outskirts with lots of interesting talks but too little time to chat with everyone, I got a half day to enjoy beautiful Cordoba yesterday.

Marcel S. Pawlowski @8minutesold.bsky.social · 2d

Thanks! You should tell Mariana if you see her. 😉

Marcel S. Pawlowski @8minutesold.bsky.social · 2d

Our results indicate that the extrapolated RAR does not seem to apply to low-mass dwarf galaxies. That's problematic for MOND, also because our target galaxies are not strongly affected by tides. So it looks like the smallest dwarf galaxies seem require to contain invisible dark matter. 7/7

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Marcel S. Pawlowski @8minutesold.bsky.social · 2d

Intriguingly, the simulated dwarfs align nicely with the observed dwarf galaxies, lying systematically above the extrapolated RAR. Their scatter is smaller, but if we mock-observe the simulations and add realistic errors, the scatter becomes comparable at the low-acceleration end. 6/7

Comparison of RAR data for observed and simulated dwarf galaxies, showing their good agreement.

Comparison of observed and simulated dwarf galaxy radial acceleration relations with mock-observed simulations indicating that realistic errors result in comparable scatter.

Marcel S. Pawlowski @8minutesold.bsky.social · 2d

We also investigate several isolated dwarf galaxies of similar stellar mass in the high-resolution EDGE simulations in a ΛCDM cosmology. Since we have perfect knowledge of the mass distributions in the simulations, we can use them to confirm that our approach reliably infers their RAR. 5/7

Radial Acceleration Relations for simulated EDGE dwarf galaxies.

Marcel S. Pawlowski @8minutesold.bsky.social · 2d

Turns out that the dwarf indeed deviate, almost all lying systematically above the extrapolated RAR (black solid line). Note that MOND's external field effect would make them lie below the RAR, and that Carina and Draco (similar distances, orbits, baryonic masses) show very different behaviour. 4/7

Radial Acceleration Relation with radially resolved data for observed dwarf galaxies in the Local Group.

Marcel S. Pawlowski @8minutesold.bsky.social · 2d

Mariana now looks for the first time at the *radially resolved* RAR for 12 dwarfs with stellar masses in the range of 10^4 to 10^7 M⊙. She infers their mass profiles from their stellar line-of-sight velocities and the GravSphere Jeans modelling code, and computes the RAR from that. 3/7

Plot of stellar mass and half light radius of our dwarf galaxy sample.

Marcel S. Pawlowski @8minutesold.bsky.social · 2d

Back in 2017, in @lellifede.bsky.social's famous RAR paper (ui.adsabs.harvard.edu/abs/2017ApJ....) we had already looked at dwarf galaxies. We found the fainter ones deviate from the RAR's extrapolation, but back then we only had one data point per dwarf, and only little data for some of these. 2/7

Plot of the Radial Acceleration Relation with Milky Way and Andromeda satellite galaxies from Lelli et al. (2017).

Marcel S. Pawlowski @8minutesold.bsky.social · 2d

Paper day! My PhD student Mariana Júlio, with @readdark.bsky.social, @pengfeili.bsky.social and others, studies the internal dynamics of dwarf galaxies and finds they don't agree with the Radial Acceleration Relation, challenging the dark matter alternative MOND.

arxiv.org/abs/2510.06905

🔭☄️🧪
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The radial acceleration relation at the EDGE of galaxy formation: testing its universality in low-mass dwarf galaxies

A tight correlation between the baryonic and observed acceleration of galaxies has been reported over a wide range of mass ($10^8 < M_{\rm bar}/{\rm M}_\odot < 10^{11}$) - the Radial Acceleration Rela...

arxiv.org

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Marcel S. Pawlowski @8minutesold.bsky.social · 3d

Congratulations to John Clarke, Michel Devoret and John Martinis for winning the Nobel Price in Physics … for Johns.

By my count from last year, this should now make it 12 men named John who were awarded the Nobel, versus a total of five women (of any name). 🧪

Marcel S. Pawlowski @8minutesold.bsky.social · Oct 8

Congratulations, the Nobel Prize in Physics 🧪 has now been awarded to twice as many guys named John than women.

(One John even got it two times.)

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Marcel S. Pawlowski @8minutesold.bsky.social · 4d

And we’re stuck on the tarmac in Berlin “for at least an hour” in a fully boarded flight because some oil-related maintenance light came on.

a close up of a car dashboard with a red triangle on the bottom right

ALT: a close up of a car dashboard with a red triangle on the bottom right

media.tenor.com

Marcel S. Pawlowski @8minutesold.bsky.social · 4d

Heading to Cordoba in Spain for IAU Symposium 403 ‘The Hidden Beauty of the Galactic Outskirts’, and from there to Chiang Mai in Thailand to give a lecture on dwarf galaxies and small-scale problems for the German-Thai ‘WE-Heraeus & NARIT Cosmology School 2025 – Galaxies and Beyond’. 🔭☄️

Marcel S. Pawlowski @8minutesold.bsky.social · 10d

Wasn’t the best or least stressful start, but people were super helpful and supportive, and the university admin went out of their way to process my moving expenses as quickly as possible, so at least I had some money to find and set up a place to live.

Marcel S. Pawlowski @8minutesold.bsky.social · 10d

Facebook reminded me that exactly 12 years ago there was another government shutdown in the U.S.

I had arrived for my first postdoc just before, applied for a SSN, but the shutdown delayed getting assigned one. Which meant that I couldn’t be paid my salary until 2 months after my international move

Reposted by Marcel S. Pawlowski

Leibniz-Institut für Astrophysik Potsdam (AIP) @aippotsdam.bsky.social · 22d

🕶️ Dunkle Materie & Zwerggalaxien: Im neuen Video der virtuellen #BabelsbergerSternenächte beantwortet @8minutesold.bsky.social vom AIP wieder Fragen zu spannenden Themen. Jetzt reinschauen! youtu.be/TZLht8_YkGU

Unsichtbare Galaxien • Rätsel der Dunklen Materie | Marcel Pawlowski

YouTube video by Urknall, Weltall und das Leben

youtu.be

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Marcel S. Pawlowski @8minutesold.bsky.social · 23d

Glad you made it. But how and why does one set off a fire in a security line?

a man in a plaid shirt is standing in front of a window and asking what is this ? what 's happening ?

ALT: a man in a plaid shirt is standing in front of a window and asking what is this ? what 's happening ?

media.tenor.com

Marcel S. Pawlowski @8minutesold.bsky.social · Sep 10

Just returned from a meeting last week, and already had to get up early for the next trip. To Brussels this time, for a workshop on “Knowledge Transfer for Policy Making” at the @leibniz-gemeinschaft.de and European Parliament.

Marcel S. Pawlowski @8minutesold.bsky.social · Aug 21

They place the pocket over where the heart is, so …

Marcel S. Pawlowski @8minutesold.bsky.social · Aug 8

This all makes so much more sense if you interpret the “PhD level experts” as referring to the numerous (mostly conservative/liberal) German politicians who have lost their degrees after it turned out that they heavily plagiarized in their dissertations.

NBC News @nbcnews.com · Aug 7

OpenAI releases the newest version of the AI model that powers its popular ChatGPT chatbot, with CEO Sam Altman promoting it as like having a “team of Ph.D. level experts in your pocket.”

OpenAI releases GPT-5, calling it a ‘team of Ph.D. level experts in your pocket’

OpenAI says its latest version of the popular AI model is better at coding, more accurate and less deceptive than previous versions.

nbcnews.to

Marcel S. Pawlowski @8minutesold.bsky.social · Aug 8

I read that as "even if poultry" first. 😂

Marcel S. Pawlowski @8minutesold.bsky.social · Aug 8

If you're interested in local developments: this 1-week research school is organized by colleagues in Germany (lead: @cosmicwebmaster.bsky.social) & Thailand. Beyond teaching junior researchers it aims to establish more of a research network between the communities indico.narit.or.th/event/223/ov...

WE-Heraeus and NARIT Cosmology School 2025 - Galaxies and Beyond

The WE-Heraeus and NARIT Cosmology School 2025 – Galaxies and Beyond is a week-long training program for students and early-career researchers from Germany and Thailand, supported by the Wilhelm and E...

indico.narit.or.th

Marcel S. Pawlowski @8minutesold.bsky.social · Aug 8

Nice end-of-semester surprise: someone from the Potsdam Graduate School appeared in my team meeting to give me a special recognition in their SUPERvisor Award.

Feels like enough of a reward to work with this amazing team, but I take any excuse to celebrate these great people with great coffee. 😉

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Reposted by Marcel S. Pawlowski

Chris Mihos @chrismihos.bsky.social · Aug 6

LLMs like ChatGPT, GoogleAI, etc are to learning what wrist magnets are to good health and vibrating belts are to weight loss.

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Reposted by Marcel S. Pawlowski

Becky Ferreira @beckyferreira.bsky.social · Jul 29

It's never aliens? Stick with me & it'll ALWAYS BE ALIENS

That's bc I'm announcing RIGHT NOW that my book FIRST CONTACT: The Story of Our Obsession with Aliens, is coming out on September 30! 👽👾🛸🚀🔭📖

Preorder here: www.hachettebookgroup.com/titles/becky...

First Contact

A narrative and visual exploration of humanity’s age-old search for and fixation with extraterrestrials.First Contact explores the ancient idea—a...

www.hachettebookgroup.com

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