The PRIMORDIAL group

Witnessing the onset of reionization through Lyman-α emission at redshift 13 - Nature Spectroscopy from the JWST Advanced Deep Extragalactic Survey of a galaxy at redshift 13 shows a singular, bright emission line identified as Lyman-α, suggesting the onset of reionization only 330 Myr...

The paper can be read in full here: www.nature.com/articles/s41...

With a nice summary here: www.nature.com/articles/d41...

And the @esa.int / Webb PR here: esawebb.org/news/weic2505/

This likely means that UV photons from the first stars can produce extended UV bubbles around galaxies earlier and much more rapidly than previously thought, allowing Lyman-alpha and ionizing photons to escape 🌫️〰️

First, there were evidence for a prominent DLA revealing dense HI gas in and around the galaxy, which now seem common at these redshifts. More exciting, was the simultanous detection of Lyman-alpha emission! This was very unexpected, and changes the reionization history of the Universe 🤯

This galaxy, called JADES-GS-z13-1, was identified and spectroscopically observed as part of the JADES survey and showed some exciting and unexpected features!

Witnessing the onset of reionization through Lyman-α emission at redshift 13 - Nature Spectroscopy from the JWST Advanced Deep Extragalactic Survey of a galaxy at redshift 13 shows a singular, bright emission line identified as Lyman-α, suggesting the onset of reionization only 330 Myr...

Paper day! And it’s a big one 🥳

Today, a team of researchers led by @joriswitstok.bsky.social — A DAWN fellow @cosmicdawncenter.bsky.social and Post-doc in the PRIMORDIAL group — published a paper in @nature.com reporting the detection of Lyman-alpha emission from a galaxy at redshift 13 (!)

🧵👇

The pairs are puzzling, because almost all models predict that such massive quiescent galaxies should only be found in pairs with number densities 10-80 times lower than observed!

The two galaxies are confirmed to spectroscopic redshifts of z~3.44 with recent JWST observations and are likely massive, M*~10^11 Msun, with surpressed star formation.

A merging pair of massive quiescent galaxies at $z=3.44$ in the Cosmic Vine We report the spectroscopic confirmation of a merging pair of massive quiescent galaxies at $z=3.44$. Using JWST observations, we confirm that the two galaxies lie at a projected separation of 4.5 kpc...

Next, we have a paper led by Kei Ito, analyzing a merging pair of massive quiescent galaxies at z=3.44 in the cosmic wine galaxy overdensity: arxiv.org/abs/2503.01953

Both these galaxies show substantial mass loading factors in the outflows, likely driven by supernovae feedback or perhaps an additional AGN contribution. These results hints at a rich variety of galaxy quenching pathways at high-z 💥

But perhaps more excitingly, there is robust evidence for a significant blueshift of typical neutral ISM absorption lines in both cases, implying substantial outflows.

These recently-quenched galaxies show a wealth of stellar absorption features and are likely massive, M*>10^10 Msun.

Gas outflows in two recently quenched galaxies at z = 4 and 7 Outflows are a key element in the baryon cycle of galaxies, and their properties provide a fundamental test for our models of how star formation quenches in galaxies. Here we report the detection of o...

The PRIMORDIAL team has two papers on ArXiv today! 🥳

The first one, led by Francesco Valentino, reports the detection of neutral gas outflows in two galaxies at z=4 and 7: arxiv.org/abs/2503.01990

Lyset fra en fjern galakse har undret astrofysikere verden over. Nu har den 23-årige fysikstuderende Chamilla Terp løst den kosmiske gåde. To professorer er imponeret over hendes enkle måde at løse gåden på.

Ungt fysiktalent har set et mystisk lys fra en fjern galakse og har løst en kosmisk gåde

Exciting article (for the Danish speaking crowd) about @chamillaterp.bsky.social (Masters student in the PRIMORDIAL group) and her recent paper published in A&A!

All this evidence point towards a scenario where GS-z14 is deeply embedded in pristine, neutral gas, fuelling its intense star formation 🤯 but is in fact consistent with many other early galaxies we’re seeing at this epoch with Webb.

We proposed a scenario where most of this gas originates outside the central, star-forming region, such that any estimates on the gas content of the galaxy based on the central-component only, would be severely biased against the full gas content (verified through 3 different approachs)

Carrying out our own independent analysis, together with Clara Pollock, @joriswitstok.bsky.social, and @chamillaterp.bsky.social here at DAWN/NBI @ucph.bsky.social, we confirmed the dense, massive foreground HI gas, completely enshrouding this remarkably bright nascent galaxy

Follow-up work by Schouws+24 and Carniani+24 used ALMA to accurately pin-point the redshift of the galaxy and found it to be somewhat lower, at z=14.179. This was consistent with a massive DLA, from dense HI gas in the line of sight! But puzzling in the context of no [CII] emission (Schouws+25)

The source, JADES-GS-z14-0, was originally found by Stefano Carniani and the JADES team, and spectroscopically determined to be at z~14.32 based on the Lyman-alpha break, potentially within the first ~280 Myr after the Big Bang!

Paper day 🥳 we are happy to present a new paper on ArXiv today, led by @kosmoskasper.bsky.social examing the most distant, spectroscopically confirmed galaxy to date at z=14.2 (!)

Read the paper here:
arxiv.org/abs/2502.06016
and see 🧵 below

Very cool find! It resembles a bit our detection of very strong DLAs in and around a massive overdensity of galaxies at z~5.4 here: ui.adsabs.harvard.edu/abs/2024arXi...

Would you in principle be able to map the HI column density distribution from the optical depth? Or perhaps too uncertain z_abs?

Lots of more cool science and results to come from the JWST-PRIMAL very soon!

We found that, at all redshifts z=5-14, there appeared to be a substantial fraction (+50%) of galaxies with strong DLAs. Further, evidence for prominent Lyman-alpha emission first started to appear at z<8, tracing the timeline of reionization.

Here, we specifically wanted to constrain the physical properties of 600 (!) galaxies at z>5, and provide a simple diagnostic to figure out if they were 1) Lyman-a emitters, or 2) had damped absorption profiles consistent with IGM or local dense HI gas.

DJA The DAWN JWST Archive

This paper compiles and interprets all the spectroscopic JWST data (for galaxies at z>5) from the DAWN JWST Archive (DJA): dawn-cph.github.io/dja/

Kickstarting the year, @kosmoskasper.bsky.social et al. published the JWST-PRIMAL paper in A&A 🥳

Link to paper here: ui.adsabs.harvard.edu/abs/2025A%26...

Link to paper here: ui.adsabs.harvard.edu/abs/2024A%26...

YouTube video by Bertil F. Dorch De første galakser (feat. Chamilla Terp) #astronomy #galaxy #universe

Throwback to 4 months ago, where PRIMORDIAL Masters student @chamillaterp.bsky.social presented her work (and first-author paper) on a mysterious galaxy at z~6 - check it out 👇

youtu.be/Ifl9mAL3Lvc?...

YouTube video by Bertil F. Dorch Nyt om astrofysik: Dissektion af de første galakser (feat: Clara Lucie Pollock) #cosmos #astro

Last week, PhD student Clara Pollock was interviewed by @astron0rd.bsky.social, talking about her work on dissecting the first galaxies and the primordial matter around them.

Check it out 👇

youtu.be/ywf-GtSuAcM?...

A new Bluesky account to highlight all the cool science from the PRIMORDIAL team at the Cosmic Dawn Center / Niels Bohr Institute, @ucph.bsky.social — follow for the latest research, papers, outreach and more!

A webpage to gather all this and more is currently in press 🔭