  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 to infer the stellar mass-halo mass relation.
We fit a single S\'ersic model to HSC $i$-band images of our galaxies and
obtain their three-dimensional half-light radii. We use these measurements to
construct a median galaxy size-mass relation. We then combine these relations
to infer the galaxy size-halo radius relation. We confirm that this relation
appears linear given the statistical errors, i.e. the ratio of galaxy size to
halo radius remains constant over two orders of magnitudes in stellar mass
above $\sim 10^{9} {\rm M}_{\odot}h^{-2}$. Extrapolating the stellar mass-halo
mass relation below this limit, we see an indication of a decreasing galaxy
size-halo radius ratio with the decline in stellar mass. At stellar mass $\sim
10^{8} {\rm M}_{\odot}h^{-2}$ the ratio becomes 30% smaller than its value in
linear regime. The possible 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 dark matter haloes of low-mass galaxies.

Astrophysics of Galaxies;Cosmology and Nongalactic Astrophysics