Harry Stephenson
@hmostevo.bsky.social
Astrophysics PhD Student at Lancaster University
Galaxies 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).
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).
September 11, 2025 at 5:56 PM
Galaxies 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).
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).
Interestingly 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!
September 11, 2025 at 5:56 PM
Interestingly 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!
This 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!
September 11, 2025 at 5:56 PM
This 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!
In 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.
September 11, 2025 at 5:56 PM
In 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.
JELS 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)
(Figure from Duncan et al. 2025)
September 11, 2025 at 5:56 PM
JELS 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)
(Figure from Duncan et al. 2025)
This 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)
(Figure from Duncan et al. 2025)
September 11, 2025 at 5:56 PM
This 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)
(Figure from Duncan et al. 2025)