Callum Donnan

The School awards annual prizes to postgraduate research students who have produced the best PhD thesis. Many congratulations to the latest winners: · Jordan Marsh · Matteo Sergola · Ryan Begley · Massi Hamadouche · Ivan Lobaskin 🙌 Full story: edin.ac/4ihORaa

New paper today!🤠 For a sample of star-forming galaxies at z ≈ 4 from the EXCELS survey, we measure the electron temperatures, densities, and the Ar/O and Ne/O abundance ratios. Our main result is that Ar/O is lower at high-z compared to local sources! arxiv.org/abs/2411.11837

My first lead-author paper is on arxiv today! 🤠 By measuring the O and Fe abundances of star-forming galaxies at z≈3.5, we constrain the stellar + gas-phase mass-metallicity relationships and find our galaxies have ubiquitously supersolar O/Fe ratios! arxiv.org/abs/2405.00774

@NatAdAstra @ACCarnall Thanks Nathan!

@CdonnanAstro @ACCarnall Massive congrats on this work! Looking forward to seeing more candidates confirmed as part of EXCELS and CAPERS in the near future!

I'm happy to present our new paper on the UV luminosity function at z=9-15! We use a combination of the PRIMER, JADES and NGDEEP surveys covering 370 sq.arcmin. and reaching depths of 30 AB mag in the deepest region. 1/6 arxiv.org/abs/2403.03171

@astrosteven Thank you!

@CdonnanAstro Congrats on a nice paper!

Many thanks to everyone who helped get this paper completed as well as to all of the work that went into designing and observing for the surveys! 6/6

Finally, we construct a simple model based on the halo mass function and find that our results do not need any alteration to LCDM, the dust content or the SF efficiency at high-z. Rather a trend towards younger stellar ages at increasing z is enough to match the observations. 5/6

New paper on the arXiv today - investigating the UV continuum SEDs of galaxy candidates at z > 8. Our main new finding is that at z > 10 the UV continuum looks uniformly `dust-free' . arxiv.org/abs/2311.06209

Excited to be presenting a poster at nam 2023, showing preliminary results from the joint analysis of rest-frame optical and UV spectra of star-forming galaxies at z~3.5, with the aim of investigating how oxygen/iron abundances scale with galaxy properties, and alpha enhancement.

New paper Day! arxiv.org/abs/2306.03916 We've used VANDELS photometry+spectra to estimate fesc(Lya), confirming a (>10sig) EW(Lya)-fesc(Lya) correlation at z~4-5. From ISM line measurements in composite spectra, we then find fesc(LyC) ~ 0.15 fesc(Lya). Go read for all the details!

@Richarwirman @CdonnanAstro @ACCarnall @SaturnsWings @aibhleog @JorgZavala For me, a huge takeaway from working with these public datasets is that we have an incredible chance to collaborate, rather than compete, with each other. This project was a lot more fun working together!

I can barely think of words to tweet after what we have done these last 2.5 days... 🫠 But here you have the first results of the greatly awaited DDT observations 😃 (Spoiler: two new spectroscopically confirmed z > 10 galaxies! 😱) arxiv.org/abs/2303.15431

This is an exceptional example and not typical of high-z galaxies followed up with NIRSpec. We have shown the incredible power of JWST to find and then verify many bright galaxies at z>10. There is clearly a large number of luminous galaxies in the very young universe!

The true solution is a strong emission line galaxy which we and other groups suggested as a secondary solution from the photometry. H-alpha contaminates 3 filters at this precise redshift allowing it to imitate the blue photometry expected in these filters for a z=16 candidate.

Our paper on the DDT program led by @Richarwirman is on arxiv! We spectroscopically confirm 2 bright galaxies at z>10. This reinforces the large abundance of bright galaxies at z>10 while showing the importance of spectroscopic verification: arxiv.org/abs/2303.15431