Postdoc at NOIRLab. Galaxy formation/evolution at high z.
Tucson, AZ
Joined February 2022
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Callum Donnan retweeted
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
Callum Donnan retweeted
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
Callum Donnan retweeted
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
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
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
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Callum Donnan retweeted
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
Callum Donnan retweeted
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.
Callum Donnan retweeted
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!
Callum Donnan retweeted
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
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
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.
Callum Donnan retweeted
It is very exciting that @Richarwirman’s @ceers_jwst DDT observations of #Maisiesgalaxy and @CdonnanAstro’s galaxy were obtained overnight. The @ceers_jwst and Edinburgh teams are hard at work on a joint paper, and we will be excited to share our results here when we submit!
