Speaker
Description
Star-forming dwarf galaxies are the most numerous galaxies in the nearby Universe, with many properties in common with the first galaxies that formed. They represent a goldmine in our own backyard for studying the baryon cycle in the smallest galaxies. Recent large multi-wavelength surveys of the Local Volume have made it possible to study these galaxies in considerable detail. Atomic hydrogen (HI) remains the primary tracer of gas in these systems as CO, the tracer of molecular gas, becomes harder to detect due to a decrease in the CO-to-H$_2$ ratio with decreasing metallicity. The atomic gas traces the total gas reservoir in dwarf irregulars -- and consequently the whole ecosystem within which stars form. I will present our efforts to study the full baryon cycle in the lowest ($<20\%$ solar) metallicity star-forming dwarf galaxies from the well-defined DustPedia sample, which has multi-wavelength coverage in 42 bands ranging from the ultraviolet to submillimeter. Adding resolved HI maps, and using SFR and dust properties derived from SED fits using a hierarchical Bayesian approach, we study the relations between various properties tracing the evolution of gas, stars and dust in the galaxies. While historically such studies have used single-dish HI fluxes, we compare the gas and dust properties within co-spatial regions using interferometric HI observations on a region-by-region basis within the galaxies. The results reveal rich and intriguing variation of dust properties within the disks of individual dwarf galaxies, and shows how the previous studies of the variation of gas-to-dust ratio with metallicity in dwarf galaxies erred by comparing metallicities measured in inner regions of these galaxies with global measurements of gas and dust. Our studies reveal how gas-to-dust properties actually vary within spatially resolved regions of low metallicity galaxies.
