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We present a population of 11 of the faintest ($> 25.5$ AB mag) shortgamma-ray burst (GRB) host galaxies. We model their sparse availableobservations using the stellar population inference code Prospector-$\beta$ anddevelop a novel implementation to incorporate the galaxy mass-radius relation.Assuming these hosts are randomly drawn from the galaxy population andconditioning this draw on their observed flux and size in few photometricbands, we determine that these hosts have dwarf galaxy stellar masses of$7.0\lesssim\log(M_*/M_\odot)\lesssim9.1$. This is striking as only $14\%$ ofshort GRB hosts with previous inferred stellar masses had $M_* \lesssim10^{9}\,M_{\odot}$. We further show these short GRBs have smaller physical andhost-normalized offsets than the rest of the population, suggesting that themajority of their neutron star (NS) merger progenitors were retained withintheir hosts. The presumably shallow potentials of these hosts translate tosmall escape velocities of $\sim5.5-80$ km/s, indicative of either lowpost-supernova systemic velocities or short inspiral times. While short GRBswith identified dwarf host galaxies now comprise $\approx 14\%$ of the totalSwift-detected population, a number are likely missing in the currentpopulation, as larger systemic velocities (observed from Galactic NSpopulation) would result in highly offset short GRBs and less secure hostassociations. However, the revelation of a population of short GRBs retained inlow-mass host galaxies offers a natural explanation for observed $r$-processenrichment via NS mergers in Local Group dwarf galaxies, and has implicationsfor gravitational wave follow-up strategies.

A Population of Short-duration Gamma-ray Bursts with Dwarf Host Galaxies