Description
Dwarf galaxies are extremely faint, limiting their direct study to the local universe (z ≲ 0.02). However, in galaxy-scale strong lenses—characterized by distinct features such as multiply imaged giant arcs—dwarf satellites within the lens galaxy can induce detectable gravitational perturbations in the background source's light. By carefully analyzing these perturbations, we can identify and characterize dwarf galaxies at much higher redshifts (z ~ 0.2 to 2.0+).
Using Hubble Space Telescope imaging of the gravitational lens SDSSJ0946+1006 (“Jackpot”), I demonstrate the successful detection of a dwarf galaxy within a strong lens. Our analysis estimates both its stellar mass (~8 × 10⁸ M☉) and dark matter mass (~10¹⁰ M☉), providing the key measurements required to determine the stellar-to-halo mass relation of dwarfs at high redshift.
Finally, I show that dwarf galaxies of this mass are detectable in Euclid's wide-field imaging and present forecasted results indicating that over the next five years, Euclid’s discovery of ~100,000 strong lenses will enable the detection of ~1,000 dwarf galaxies via this method.
