Reposted by Harry StephensonJohn Stott @jpsastro.bsky.social · 11/09/2025New JWST paper from Lancaster’s @hmostevo.bsky.social 🧪🔭 #extragalactic 063
Harry Stephenson @hmostevo.bsky.social · 11/09/2025"Evidence that pre-processing in filaments drives the anisotropic quenching of satellite galaxies in massive clusters": academic.oup.com/mnras/articl...academic.oup.comEvidence that pre-processing in filaments drives the anisotropic quenching of satellite galaxies in massive clustersABSTRACT. We use a sample of 11 $z\approx 0.2\!-\!0.5$ ($z_{\text{med.}} = 0.36$) galaxy clusters from the Cluster Lensing And Supernovae survey with Hubbl 011
Harry Stephenson @hmostevo.bsky.social · 11/09/2025P.S. If you are interested in my other works, you can check them out in the below links: Quasar Sightline and Galaxy Evolution (QSAGE) – III. The mass–metallicity and fundamental metallicity relation of z ≈ 2.2 galaxies: academic.oup.com/mnras/articl...academic.oup.comQuasar Sightline and Galaxy Evolution (QSAGE) – III. The mass–metallicity and fundamental metallicity relation of z ≈ 2.2 galaxiesABSTRACT. We present analysis of the mass–metallicity relation (MZR) for a sample of 67 [O iii]-selected star-forming (SF) galaxies at a redshift range of 110
Harry Stephenson @hmostevo.bsky.social · 11/09/2025I'll leave it there! A huge thanks goes Dr Kenneth Duncan and Corey Pirie for all their advice throughout this project, and of course to @jpsastro.bsky.social for his supervision! Keep an eye out for other JELS papers! I have linked my paper again here. Cheers! arxiv.org/abs/2509.08045arxiv.orgThe \emph{JWST} Emission Line Survey (JELS): The sizes and merger fraction of star-forming galaxies during the Epoch of ReionizationWe used observations from the \emph{JWST} Emission Line Survey (JELS) to measure the half-light radii ($r_{e}$) of 23 H$α$-emitting star-forming (SF) galaxies at $z=6.1$ in the PRIMER/COSMOS field. Ga... 100
Harry Stephenson @hmostevo.bsky.social · 11/09/2025Our results, combined with recent literature results, show that star-forming galaxies during the EoR build-up inconsistently through bursts of star formation. We suggest a more complex approach to galaxy evolution is needed at this epoch. 110
Harry Stephenson @hmostevo.bsky.social · 11/09/2025Galaxies build up their stellar mass either through in-situ star formation, or from mergers. Given this, we determined a (major) merger fraction using close-pair analysis. Below is how our results compare to other studies, with good agreement with Puskás et al. (2025). 100
Harry Stephenson @hmostevo.bsky.social · 11/09/2025Pirie et al. (2025) found these galaxies are undergoing a current burst of star formation. Mounting evidence in the literature suggests EoR galaxies have bursty star-forming histories. So, combined with this, our results suggest these previous episodes may have been bursts! 100
Harry Stephenson @hmostevo.bsky.social · 11/09/2025Interestingly we found that emission from the established stellar populations is marginally more extended than the star-forming regions traced by Hα, as well as the near-UV (F277W). This suggests that previous episodes of star formation must have occurred to form this population! 100
Harry Stephenson @hmostevo.bsky.social · 11/09/2025This offset is expected, and using our size-mass relationship in rest-R-band (F444W) at 10^9.25 solar masses, we find an average size of ≈ 0.76 kpc. This is in good agreement with other studies at z ≈ 6, and a variety of size-z relationships from observations and simulations! 100
Harry Stephenson @hmostevo.bsky.social · 11/09/2025In our work, we measure the half-light radius of 23 HAEs at z=6.1 to determine the size-mass relationship at the EoR at multiple rest-frame wavelengths (near-UV, optical and Hα). We find a slope that agrees with the literature, but is negatively offset in size from lower-z works. 100
Harry Stephenson @hmostevo.bsky.social · 11/09/2025The sample we use for our work stems from the v0.8 z=6.1 Hα-emitters (HAEs) catalogue described in detail by Corey Pirie (Edinburgh) in his similarly excellent paper! We refer to this as the "parent" catalogue. I will delegate all the details to his work: academic.oup.com/mnras/articl...academic.oup.comThe JWST Emission Line Survey (JELS): an untargeted search for H α emission line galaxies at z > 6 and their physical propertiesABSTRACT. We present the first results of the JWST Emission Line Survey (JELS). Utilizing the first NIRCam narrow-band imaging at 4.7 $\mu$m, over 63 arcmi 110
Harry Stephenson @hmostevo.bsky.social · 11/09/2025The possible science that will come from JELS is very exciting because of the nature of its homogeneous sample selection! For all the details on the JELS observations and strategy, please see Kenneth Duncan's (Edinburgh) excellent survey paper: academic.oup.com/mnras/articl...academic.oup.comThe JWST Emission-Line Survey: extending rest-optical narrow-band emission-line selection into the Epoch of ReionizationABSTRACT. We present the JWST Emission-Line Survey (JELS), a JWST imaging programme exploiting the wavelength coverage and sensitivity of the Near-Infrared 110
Harry Stephenson @hmostevo.bsky.social · 11/09/2025JELS isolates the Hα emission line using JWST NIRCam F466N & F470N narrow-band filters at z = 6.1. Hα is associated with regions of active star formation as it originates from recombination in gas ionised by massive, short-lived (~10 Myr) stars. (Figure from Duncan et al. 2025) 100
Harry Stephenson @hmostevo.bsky.social · 11/09/2025This work is the first full science paper from the JWST Emission Line Survey (JELS) - the first survey to perform narrow-band rest-optical emission line selection with JWST, and also the first to do so at the Epoch of Reionization (EoR)! (Figure from Duncan et al. 2025) 100
Harry Stephenson @hmostevo.bsky.social · 11/09/2025Hello everyone! My first Bluesky posts! I am very pleased to share that my 3rd first-author paper of my PhD is now available on arXiv! The paper has also been submitted to MNRAS following minor suggested revisions from the anonymous referee! arxiv.org/abs/2509.08045 Thread on the details 🧵arxiv.orgThe \emph{JWST} Emission Line Survey (JELS): The sizes and merger fraction of star-forming galaxies during the Epoch of ReionizationWe used observations from the \emph{JWST} Emission Line Survey (JELS) to measure the half-light radii ($r_{e}$) of 23 H$α$-emitting star-forming (SF) galaxies at $z=6.1$ in the PRIMER/COSMOS field. Ga... 1213
