Department of Astronomy

Graduate student Laurin Gray’s paper “Catching Tidal Dwarf Galaxies at a Later Evolutionary Stage with ALFALFA” has just been accepted for publication in The Astronomical Journal.  Laurin investigated the origins of an unusual set of galaxies called “Almost-Dark galaxies” that are extremely faint at optical wavelengths but are rich in hydrogen gas.  Laurin used images from the WIYN 3.5-m optical telescope to measure the galaxies’ stellar populations and radio data from the Westerbork Synthesis Radio Telescope to study the hydrogen gas. She finds that some of the galaxies in her sample have relatively low amounts of dark matter, which suggests they may have formed when they were stripped out of nearby massive galaxies through gravitational interactions.  Typical “Tidal Dwarf Galaxies” formed in these types of interactions are fairly young, but the galaxies in Laurin’s sample appear to be older and more evolved. The paper’s co-authors include Laurin’s Ph.D. advisor Katherine Rhode, faculty member John Salzer, and several other current and former members of the department.