Needles in a Haystack: "Almost Dark" Galaxies in the ALFALFA Survey
by Luke Leisman (Cornell)
Abstract.
Scaling relations between atomic hydrogen and stars in galaxies
suggest strong ties between their atomic gas content and star
formation laws. The Arecibo Legacy Fast ALFA (ALFALFA) blind
extragalactic HI survey is well positioned to locate very low surface
brightness sources that lie off these relations, the most extreme of
which may fall below optical detection limits. Thus, the ALFALFA
(Almost) Darks Project has been investigating extreme outliers from
these relations, searching for sources with highly suppressed star
formation laws. This talk will present results from this project,
including an isolated population of gas-rich galaxies with stellar
masses of dwarfs, but optical radii similar to the Milky Way, and will
explore what these sources teach us about the suppression of star
formation in galaxies.