http://arxiv.org/abs/2301.04664
We investigate the stellar mass-dependence of the galaxy size-dark matter halo radius relation for low redshift galaxies using weak gravitational lensing measurements. Our sample consists of $\sim$38,000 galaxies more massive than $10^{8} {\rm M}{\odot}h^{-2}$ and within $z<0.3$ drawn from the overlap of GAMA survey DR4 and HSC-SSP PDR2. We divide our sample into a number of stellar mass bins and measure stacked weak lensing signals. We model the signals using a conditional stellar mass function formalism to infer the stellar mass-halo mass relation. We fit a single S\’ersic model to HSC $i$-band images of our sample galaxies and obtain their three-dimensional half-light radii. We use these measurements to construct a median galaxy size-mass relation. We then combine the two relations to derive the relationship between galaxy size and halo radius. We confirm that the galaxy size-halo radius relation is roughly linear over two orders of magnitudes in stellar mass above $\sim 10^{9.35} {\rm M}{\odot}h^{-2}$. Below this stellar mass, we see evidence of a downward departure from this linearity of up to 25 percent at stellar masses of $10^{8.7} {\rm M}{\odot}h^{-2}$. If the stellar mass halo mass relation is extrapolated to lower mass scales, our galaxy size measurements imply these deviations can reach even as high as 50 percent at $10^{8} {\rm M}{\odot}h^{-2}$. The existence of a such trend in dwarf galaxy sectors calls for either modification in models employing a constant fraction of halo angular momentum transferred to explain sizes of dwarfs or else points towards our lack of knowledge about the host dark matter haloes of such low-mass galaxies.
P. Mishra, D. Rana and S. More
Fri, 13 Jan 23
20/72
Comments: 19 pages, 11 figures, submitted to the MNRAS
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