The Nature of Low-surface-brightness Galaxies in the Hyper Suprime-Cam Survey

Abstract

We present the statistical redshift distribution of a large sample of low-surface-brightness (LSB) galaxies identified in the first 200 deg 2 of the Hyper Suprime-Cam Strategic Survey Program. Through cross-correlation with the NASA–SDSS Atlas, we find that the majority of objects lie within z < 0.15 or ∼500 Mpc, yielding a mass range of M * ≈ 10 7 −10 9 M ⊙ and a size range of r eff, g ≈ 1−8 kpc. We find a peak in the distance distribution within 100 Mpc, corresponding mostly to ∼10 7 M ⊙ galaxies that fall on the known mass–size relation. There is also a tail in the redshift distribution out to z ≈ 0.15, comprising more massive ( M * = 10 8 − 10 9 M ⊙ ) galaxies at the larger end of our size range. We see tentative evidence that at the higher-mass end ( M * > 10 8 M ⊙ ), the LSB galaxies do not form a smooth extension of the mass–size relation of higher-surface-brightness galaxies, perhaps suggesting that the LSB galaxy population is distinct in its formation path.