SBI Field Level Inference workshop at Perimeter this June Hurry up! events.perimeterinstitute.ca/event/1924/

Working on the problem from two completely different angles is the best part of this project we’ve been hammering for months Matthijs: pristine, elegant, mathematically flawless Niko: “okay but imagine the posterior is a traffic cone…” Somehow… we are both correct 🤣🤣

Apparently Matthew McConaughey was at Duke today and I missed meeting him because I was stuck in telecons/working from home This is NOT alright alright alright I’m really upset

Minor pet peeve: describing ΛCDM-based analyses as having the “potential to discover new physics.” They can reveal tensions or inconsistencies that may motivate extensions to the model — but that’s not the same as discovering new physics. Cmon my man, tone that down

Happy bday, arXiv! You are the best! Funny coincidence is that I chose to wear one of my arXiv shirts (which are top quality btw! Hoodies as well, highly recommend)

I am a science machine 💪💪💪💪 4th paper fresh on the @arxiv.bsky.social this year 🥳🥳🥳 arxiv.org/pdf/2603.09973

I was in a clusters telecon today (not my usual working group) and am so beyond impressed by the quality of plots people were showing. I find it so refreshing to see there are people out there who care about communicating their research

Impact and interplay of $Λ$CDM analysis choices for LSST cosmic shear. N. C. Robertson et. al. https://arxiv.org/abs/2602.21863

Starting the day shearing dead weeds in the forest and cutting through mountain mint — that sharp minty scent mixed with damp, rotting leaves — pure peace for the soul 🌿 And catching up with the wonderful folks over at @DukeLemurCenter is just 👌chefs kiss

Two more works on the @arxiv 🥳🥳🥳 arxiv.org/abs/2602.21863 arxiv.org/abs/2602.21280

Aaaaaand it’s officially on @arxiv.bsky.social 🥳🥳 arxiv.org/abs/2602.08078 Wanna do Fisher, XY Fisher or DALI with a chosen derivative method backend in a simple sleek Python way? Look no further, my friend. We got you! Simple examples here docs.derivkit.org/main/example...

Ok, aside that this was ten years ago (wthhhhell 😱) and I now feel ancient, it is actually nice to be reminded of good times during masters in Göttingen: Thorsten was my lecturer in cosmology and string theory courses and was super encouraging. Made me fall in love with cosmo 🤩

Actually — the first burek in the states since I moved 😱 Found the ingredients at Whole Foods Also a selfie just because

X marks the spot Happy first day of 2026! It’s cold here but nothing beats the Carolina blue 😍

There probably are a few things better than talking to Alan Heavens about a potential idea then heading to the woods and mulching sumac trees (for the lemurs!) with your best guy on a warm December morning but I can’t think of any right now. I just love the 🇺🇸 🍂🛻🪏

I swear if I hear another physicist say “we are not software engineers and we should not try to be” I’ll flip the freaking table. No, Dave, it exactly is our job. You need to know how to tell computer to do physics. And you are doing it in a very bad way. 1/

last day of classes! here's the collection of Jupyter notebooks illustrating stellar physics concepts I made for my grad Stars class this semester: zingale.github.io/stars/notebo... #astro

If you are around these parts, come and join us for a pint and a nice story about the Universe

🤣🤣🤣🤣🤣🤣

Happy Thanksgiving :) @desisurvey.bsky.social

Investigating the Dark Energy Constraint from Strongly Lensed AGN at LSST-Scale. Sydney Erickson et. al. https://arxiv.org/abs/2511.13669

I can say with full confidence I’m the happiest person on this planet right now. Seeing the Roman Space Telescope being assembled — and knowing it’ll be in orbit next year — just makes it unreal.

Hello again, DC 🤗

It’s a wrap! @nasaromantelescope.bsky.social NASA Roman HLIS Cosmology Project Infrastructure Team face to face meeting Thank you to Bhuv, Mike and the rest of UPenn folk for hosting us 🙏

Hey all I need help from my physics peeps (and beyond) Do you (or if you are a PI: your students/postdocs) use numerical derivatives in your research? Especially in inference (but also in general) Apparently I can’t do a poll here so pls respond and share

The only acceptable way to start the Leiden research visit is to have coffee with Dr Evil Villain (in our secret Narnia caffe) @ivovanvulpen.bsky.social (For those of you who don’t know, Ivo is responsible for the amazing wall formulas in Leiden; see photo 2 where Matthijs and I are kissing)

Happy to be back in one of the loveliest places on this planet 🇳🇱🚲🌷🧀🌊

Interested in a fully funded PhD place in Experimental Particle Physics in Edinburgh? We have fully funded studentships, including a specific scholarship for students from a Black heritage (including mixed Black background). More info: inspirehep.net/jobs/3080808

Statistical properties of the gravitational force through ordering statistics. Constantin Payerne et. al. https://arxiv.org/abs/2201.08478

One of the perks of academia — you have awesome colleagues all over the world so dinners in great company are always guaranteed

Lovely day at the Paris observatory with old Twitter friends! All Paris talks delivered!

When two stats nerds from way back randomly find themselves in Paris at the same time — talk about serendipity!!!! @knut.dundasmora.no 😍 It was beyond lovely to spend an afternoon in Paris with you

Bonjour!

Happy Halloween from me and my buggy code

A little treat for myself: two adorable mini Kurt Geiger bags ✨ My first one was a Heathrow purchase two years ago — guess it was the start of a collection 👀

helloooooooooooooooooooo wanna learn about telescopes and how to navigate the night sky? funny you mention that, because we're doing another starhopping and telescopes night with @spacecentreyvr.bsky.social on november 12!! get your f r e e tickets here: 🔗 www.eventbrite.ca/e/rasc-vanco... 🔭🌌

clicked to generate a random xkcd and it could have not be more appropriate considering my current situation xkcd.com/2797/

🤬 why does everything pass locally on macOS but CI (Linux) decides my cubic’s 3rd derivative is 24.0000001999 instead of 24?! Apparently OpenBLAS and Apple’s Accelerate don’t round the same way 🤦‍♀️ IT IS UNIXXXXXXXX Numerical analysis: 1, sanity: 0 (Managed to fix, still angry)

6 °C in Durham this morning 🌿 Early woods + chilly air = time to grab a shovel! Cleared out a bunch of sweet gum trees — perfect, since we’re expanding the food gardens AND the lemurs get a feast 🍃 A wonderful morning at the Duke Lemur Center with my garden crew 🦋

I also spent some hours this weekend giving my @github profile a glow-up — it’s orange 🟠 and has parrots 🦜 check it out: github.com/nikosarcevic

spent an embarrassingly long time making these plots (wanted to procrastinate) holy pagan gods, @matplotlib has been on fireeeee 🔥 the past few days i think they’re correct … but for now i’m just gonna enjoy looking at them because they pretty 🤩 thanks to @matthijs.vanderwild.com for helping 😍

The sky is particularly beautiful here in NC So is the Moon 🌕🤩

In response to increasing activity, we wish to add more members to our Editorial Board. We're looking for expertise in any area of astrophysics, but people working in instrumentation or stellar astrophysics are particular welcome. Please contact us here if you want to volunteer! astro.theoj.org

New paper out, baby We build & validate six intrinsic alignment models infused directly into weak lensing simulations, enabling robust inference beyond 2pt stats. I led the full validation with MCMC chains—took years to get here! Excited this is FINALLY out 🎉 arxiv.org/abs/2509.25166

Yesterday I submitted 6 prs that were perfect not only to review but also to merge and rebase with no conflicts. I was proud. Today I do one pr on top of two PRs and suddenly there is a merge conflict cherry pick hell I’m going to go listen to Maynard screams on YouTube

Dark Energy Survey Year 6 Results: improved mitigation of spatially varying observational systematics with masking. M. Rodríguez-Monroy et. al. https://arxiv.org/abs/2509.07943

I am so good at multitasking between bash WhatsApp and slack

Oh you bought another book? Did you finish the life sentence yet? Yes. No. Also, blame it on @telescoper.bsky.social for posting about this book yesterday.

In the past 2 weeks I have reviewed 5 papers — 3 for journals and two of the ones I’m involved with Also countless PR reviews back and forth I don’t have eyes any more 👀👀👀👀🔥🔥🔥🔥🔥🔥🔥