Marking first year exams and a student described the collision of two black holes as a "severe incident".

Paper Day! arxiv.org/abs/2603.04025 Mehraveh Nikjoo, a PhD student at the University of Gdansk, led our search for a lensing signal around ridges in foreground galaxy density fields.

Reminiscing today on our old stand-up show & @joezuntz.bsky.social's uncannily prophetic joke "her main duty is to fight the Astronomer Royal for England. And fortunately he's 80, so one quick smack with an 18 inch telescope & down he goes"😇 AR🏴󠁧󠁢󠁳󠁣󠁴󠁿 v New AR🇬🇧 STFC CEO Westminster: 4th Mar

I think I'm now at the point where I could best speed up my research by offering to help other people using the same computing cluster optimize their code.

@royalastrosoc.bsky.social I just had to choose "Prefer not to say" for everything on the final "Diversity" section of your Michael Penston Prize nomination form because it was completely unclear if you were asking for info about me or about the nominee. Might be worth clarifying on the page.

Academic presentations are a really good training ground for thinking on your feet, and being able to answer really varied questions. That training tonight allowed me to improvise ten verses of “The Dinosaurs Went In Two By Two” when my son decided that was the goodnight song he wanted.

I made a thing.

First paper from my PhD student Yun-Hao Zhang! arxiv.org/abs/2508.20903 While preparing to put together data for another project, Yun-Hao came up with a way to improve a technique from our colleagues for galaxy redshift estimation. This is the first of two papers laying out and testing the method

So there's about a seventeen different likelihood codes for the Planck CMB mission. Can anyone explain to me which are 1) currently widely useful, 2) handy to keep to compare old results to, 3) obsolete?

We’d planned to return for #NAM2025 but the conference wifi won’t display this account. Or the program. Or anything about NAM. Is the conference itself now unofficial @robertmassey.bsky.social ?

Just arrived for #NAM2025. Very nice to be here, and seen people I know already - hi @ritatojeiro.bsky.social! Weirdly I can't seem to get to the conference even website though.

There is a concept called "stolen valour", where people pretend to be military to get prestige or free stuff. I think in science and other discourse we see a lot of "stolen rigour": authors borrow a concept from maths/stats/some "hard" science, and use it to give authority where it isn't deserved.

When you're writing exam questions you really have to go through them like a lawyer and see if you can misconstrue a question in any way at all. Any possible interpretation, no matter how sensible, at least one student will use!

If you read the first letter of every paragraph it spells out "George was right".

I am looking for a PhD student to work on beyond 2-point statistics for galaxy clustering & weak lensing as part of my Grant "Probing cosmic large-scale structure beyond the average" Details: uni-bielefeld.hr4you.org/job/view/417... Please share in your networks and encourage candidates to apply!

New Publication at the Open Journal of Astrophysics: "Baryon-free S_8 tension with stage IV cosmic shear surveys" by Ottavia Truttero, Joe Zuntz, Alkistis Pourtsidou and Naomi Robertson (University of Edinburgh, UK). astro.theoj.org/article/1299... IV cosmic shear surveys"

First 2025 release of GLASS is out: github.com/glass-dev/gl... It comes with a big change that allows you to easily create FLASK-like simulations from a set of n(z) without simulating the entire lightcone. This isn’t usually the best way to go, but can sometimes be.

[1/3] The old joke TV listings site TVGoHome once included a movie "Die Hard Through A Cow", where "Die Hard" was shown to a dairy cow and its brainwaves scanned to reconstruct the movie, as filtered through the bovine mind.

It's a crazy world where it is cheaper to see Iron Maiden with a VIP ticket than to attend the Euclid Consortium Meeting >.<

Are you on the Postdoc market and excited about early science with @vrubinobs.bsky.social, especially time domain, solar system, near field cosmology, or SETI? Well check out the @dirac-institute.bsky.social fellowship position that just got posted! apply.interfolio.com/158267

Preparing for our new Dark Universe undergraduate course next semester, I'm putting together various animations and illustrations. Here's a few of my favourite ...

Photons, meet the Commissioning Camera 🤝 On October 24, Rubin staff successfully completed the first end-to-end on-sky test of the full telescope system using the testing camera — from capturing the sky to transferring data to SLAC! 🔭🧪 🔗: https://rubinobservatory.org/news/test-camera-sees-sky

Just had the best idea for a CubeSat. en.m.wikipedia.org/wiki/Russell...

First paper by my student Ottavia Truttero! We explore using very conservative scale cuts in LSST weak lensing to completely cut out baryonic effects of the power spectrum. Stage IV power is so high that we may still detect S8 tension with only large-scale data arxiv.org/abs/2410.18191

Crazy to read about the training programme for the 100m Olympic runners. Apparently they start very gradually, running only 1 or 2m per week, then building up to 50m the week before the race.

It's very nice to be able to share that I've been promoted to Professor of Cosmology at the University of Edinburgh.

Message to Gen Z: I know your entire conception of human culture is built around photos with captions on, but when you're sending an error message to get help with some software, please don't send a screenshot of text. It's slower than copy/pasting anyway.

I'm in the middle of a fascinating teaching project: designing a second course for physics students in programming and computer modelling, but incorporating and allowing use of AI assistants in their work.

New Publication at the Open Journal of Astrophysics: "Comparing Mass Mapping Reconstruction Methods with Minkowski Functionals" by Nisha Grewal (U. Edinburgh, UK), Joe Zuntz (U Ediburgh, UK) and Tilman Tröster (ETH Zurich, Switzerland) astro.theoj.org/article/1203...

Back to the office today after 4 months of paternity leave! Wonder if I'll have forgotten how to do stuff. First task is to clear out about 1000 emails.

Very excited to be doing the wonderful Bright Club - where academics do stand-up comedy - on 31st January at The Stand in Edinburgh! I’ll be talking about the wonders of teaching. Come along! www.thestand.co.uk/performance/...

Since January 1st 2024, Monthly Notices of the Royal Astronomical Society is charging an APC of £2,310 (approx. €2690) per paper for Open Access publication. That's more *for one paper* than the entire annual running costs of the Open Journal of Astrophysics.

Now my charms are all o'erthrown / And what strength I have’s mine own / Which is most faint. Now, ’tis true / All I want for Christmas is you

🔊Seeking a new postdoc for our Cosmology group in Edinburgh, with experience in machine learning and differentiable inference. 🧪 ⚛️ 🔭 #CompSky You'd work with the fab @joezuntz.bsky.social and me, within the Rubin Observatory Dark Energy Science Collaboration. 👉 jobregister.aas.org/ad/20c9bfda

I've been learning the Julia programming language in order to try to integrate autodiff methods more into mainstream cosmological inference. Coming from a python perspective, there's a few things I've noticed about the language (i.e. complaints) that I think it's worth describing.

Just done finished day 1 of 2 of my intensive postgraduate course Data Science for Society! We give our student teams data sets of social relevance and have them explore in a self-driven hackathon, and present at the end. I really recommend this approach, you get some great engagement.

I manage a fairly complex conda development environment for the LSST collaboration. Whenever something goes wrong, it's always with Google JAX.

I’m currently travelling. At Frankfurt airport the cigarettes and vaping area was signed as the “Camel Smoking Area”. Sadly, the least interesting of the three interpretations I could think of seemed to be the right one.