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arXiv · 2401.03592

Surface Brightness Bias in the Shape Statistics of High-Redshift Galaxies

Abraham Loeb
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Abstract

Recently, Pandya et al. (2023) argued that the shapes of dwarf galaxies in JWST-CEERS observations show a prolate fraction that rises from ~25% at redshifts z=0.5-1 to ~50-80% at z=3-8. Here we suggest that this apparent change could result from a surface-brightness bias, favoring the detection of edge-on disks at low-luminosities and high-redshifts. Changing edge-on projections with an axis ratio of 10 to a face-on orientation reduces their apparent surface brightness by 2.5 magnitude per arcsec$^2$ and could shift a substantial fraction of the observed galaxies below the detection limit.

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Abraham Loeb. 2024-01-07. Surface Brightness Bias in the Shape Statistics of High-Redshift Galaxies. https://arxiv.org/abs/2401.03592

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