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Joe Zuntz

@joezuntz

Professor of Cosmology at the University of Edinburgh.

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19.09.2023
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Latest posts by Joe Zuntz @joezuntz

We find a nice signal, with a clearly interpretable strucutre, though we haven't yet tried to disentangle it from the signal around foreground galaxies themselves, usually called galaxy-galaxy lensing. We have some ideas for that in future work.

05.03.2026 11:27 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Weak Lensing by Photometric Density Ridges Ridges in galaxy density fields measured by photometric surveys are 2D projections of filaments in the cosmic web, and so should lens light from background galaxies. We report on a detection of this e...

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.

05.03.2026 11:27 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

It makes sense in context, I promise!

28.02.2026 09:00 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

The fun part of Catherine going off to London to fight for astronomy funding is that she isn’t around to stop me ending our grant proposal with the words β€œPeppa Pig Goes To Outer Space”.

28.02.2026 08:29 πŸ‘ 3 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
Two people on a dark stage wearing black with microphones in the middle of a stand up show.  Catherine has her trademark red heals on, as always.  Joe is trying to compete with his red trainers but isn't nearly as classy.

Two people on a dark stage wearing black with microphones in the middle of a stand up show. Catherine has her trademark red heals on, as always. Joe is trying to compete with his red trainers but isn't nearly as classy.

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"πŸ˜‡

AR🏴󠁧󠁒󠁳󠁣󠁴󠁿 v New ARπŸ‡¬πŸ‡§ STFC CEO Westminster: 4th Mar

28.02.2026 07:30 πŸ‘ 55 πŸ” 7 πŸ’¬ 3 πŸ“Œ 2

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.

19.02.2026 09:27 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

@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.

26.01.2026 18:17 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

I was especially proud of rhyming β€œwent in six by six” with β€œarchaeopteryx”.

08.12.2025 20:23 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

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 β€œThe Dinosaurs Went In Two By Two” when my son decided that was the goodnight song he wanted.

07.12.2025 20:14 πŸ‘ 5 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Full text is here: public.oxford.gov.uk/online-appli...

16.11.2025 08:13 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

I love that the resulting planning dispute ended up being decided by the secretary of state. And the chief planner wrote the wonderful: "any system of control must make some small space for the the dynamic, the unexpected and the downright quirky, or we shall all be the poorer for it"

16.11.2025 08:13 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

This looks very nice, but the killer feature in conda-forge for me is support for non-python dependencies. It looks like this is focused just on pypi, so python only.

26.10.2025 12:30 πŸ‘ 4 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

This is brilliant, I’m going to get fake credit for half of the Dark Energy Survey!

26.10.2025 12:29 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
Post image

I made a thing.

09.10.2025 18:15 πŸ‘ 13 πŸ” 2 πŸ’¬ 1 πŸ“Œ 0

I’m pretty sure OJA counts as a mainstream journal now!

08.10.2025 20:46 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

This was the basis of another of my comments on @astroroyalscot.bsky.social’s code

03.09.2025 17:52 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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Improved photometric redshift estimations through self-organising map-based data augmentation We introduce a framework for the enhanced estimation of photometric redshifts using Self-Organising Maps (SOMs). Our method projects galaxy Spectral Energy Distributions (SEDs) onto a two-dimensional ...

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

01.09.2025 07:42 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

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?

20.08.2025 08:47 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

I did have to add a handwritten exam to make sure they could actually write some code unassisted.

11.08.2025 19:02 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

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 ?

07.07.2025 08:44 πŸ‘ 2 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

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.

06.07.2025 16:25 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

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.

26.05.2025 09:37 πŸ‘ 1 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

I actually sent feedback about this to AQA a few days ago, as the largest exam board.

22.05.2025 13:43 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

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!

15.05.2025 10:18 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

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

26.03.2025 14:02 πŸ‘ 6 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Research position (PhD student) in the field of cosmology The Cosmology and Astroparticle Physics group investigates the formation and evolution of large-scale structures in the Universe, the nature of dark m...

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!

24.03.2025 07:42 πŸ‘ 10 πŸ” 14 πŸ’¬ 1 πŸ“Œ 0
Baryon-free $S_8$ tension with Stage IV cosmic shear surveys | Published in The Open Journal of Astrophysics By Ottavia Truttero, Joe Zuntz & 2 more. A study of the effect of vbaryonic feedback oin the dtermination of cosmological parameters and the possibility of using large-scale clustering information onl...

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"

24.02.2025 08:58 πŸ‘ 3 πŸ” 3 πŸ’¬ 0 πŸ“Œ 1

We should tell students that in this situation it’s perfectly fine to accept the offer from the group and then change your mind later. They haven’t signed a contact.

26.02.2025 17:46 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
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Release glass 2025.1 Β· glass-dev/glass First 2025 release of GLASS. Release note Changelog Full list of commits

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.

23.02.2025 11:54 πŸ‘ 5 πŸ” 3 πŸ’¬ 0 πŸ“Œ 0

[3/3] That's what it's felt like trying to use the "R" programming language this week.

31.01.2025 08:58 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0