Benedikt Diemer

Astronomy on Tap Tickets | Free | 18 Feb @ DC9, Washington D.C. | DICE ͏feat: beer, trivia & space talks BAR OPENS at 5:00PM Astronomy on Tap DC features 3 speakers giving engaging talks about the Universe and prize giveaways....

Do you lie awake at night worrying about cosmic collapse? On Feb 18th, @benedikt.bsky.social will tell us why cosmic collapse keeps your lights on! Curious? Come to @dc9club.bsky.social to learn more!
RSVP for your free ticket here: dice.fm/event/py7okw...
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This should be a fun one! Really looking forward to finally doing AoT DC 🍺🔭

Turns out, the dust modeling / RT is the hard part, but Andrea crushed it.

The short answer: conventional dust models definitely fail at reproducing massive red galaxies (DSFGs etc.). They can be reproduced, but only with some pretty extreme (unrealistic?) dust screens.

Lots more in the paper...

The mass-dependent UVJ diagram at cosmic noon: A challenge for galaxy evolution models and dust radiative transfer Context. The UVJ color-color diagram is a widely used diagnostic to separate star-forming and quiescent galaxies. Observational data from photometric surveys reveal a strong stellar mass trend, with h...

I'm super excited about this paper on the arXiv today led by UGent grad student Andrea Gebek!

Why are there basically no red galaxies in IllustrisTNG at cosmic noon? It's tempting to think that there might be something wrong about SFRs, but what about dust...

arxiv.org/abs/2501.12008

And indeed, there is some information in the maps, meaning we can improve on just assuming the average accretion rate at fixed mass. However, the accuracy isn't nearly what we'd like it to be... which means there just isn't enough information even in combined X-ray + SZ! The search continues...

On the arXiv: great work led by graduating student John Soltis and Michelle Ntampaka.

The issue: the accretion rate is key for the properties of cluster halos, but we have no reliable observational proxies. So we decided to use ML to look for "optimal" info in realistic X-ray/SZ maps from MTNG.

Wrapping up 10 days in China by catching up with my undergrad adviser (after 16 years), friends, and collaborators... thanks for the fantastic visits, Tsinghua and Jiao Tong! A truly memorable trip. Apologies to all the ducks that got harmed in the process.

Just logged out of twitter for good and my mental health immediately improved by 6.3%

The timing was amazing... half your figures just went onto my class slides for tomorrow :)

Happy to add you to the repo... email me

It's not public at the moment, but happy to share! Are you interested in doing something similar?

Nothing's perfect, so please let us know how we can improve Colossus-Web! There's a link to a feedback form at the bottom of the page.

We aren't planning on a release paper at this time, so please RT if you enjoy the calculator and think it's relevant to your followers!

3) Advanced cosmological parameters: different dark energy models, relativistic species, etc.

4) Advanced calculations: correlation functions, peak height, etc. Power spectra can be calculated via fitting functions or using CAMB.

So what can Colossus-Web do? A few highlights:

1) Graphical interface: you can plot tons of cosmological functions and download the data to csv files.

2) Multiple cosmologies: you can compare as many pre-programmed cosmologies as you want, or create your own.

First of all, most of the credit goes to Erik Chou, a fantastically talented UMD undergraduate. He crushed this project, and you should (try to) hire him in '25!

echou.notion.site/Erik-Chou-bb...

Need the age of the Universe at z = 5 but only got a phone? Wanna compute a correlation function without python? Fear not, for we are proudly presenting Colossus-Web, a powerful online cosmology calculator!

colossus.astro.umd.edu

More info in replies...

UMD astronomy is hiring! It's an open call, though we're particularly interested in observers this time. Feel free to message if you're interested and have questions, since I went through the process not that long ago.

jobregister.aas.org/ad/2ac49c51