The power of crowdsourced citizen science lies in its ability to turn millions of hours of volunteers’ contributions into scientific research that would never have been possible before. Scientists published several papers last month that expand our understanding of galaxies and star formation.
A spirally, jet-y, halo-y sort of thing
With the memorable name J1649+2635, its friends call it J1649, the galaxy combines features of several different galaxies. It has the well-formed spiral arms of a grand design spiral galaxy, but it also has features of older elliptical galaxies with jets of particles shooting from a black hole at the galaxy’s center and a dense halo of stars. Scientists at the University of Maryland found J1649 when they matched a list of spiral galaxies from the Galaxy Zoo catalog with catalogs of deep space radio sources. Co-author Sylvain Veilleux spoke with the Baltimore Sun last month about working with crowdsourced data:
While the Monthly Notices of the Royal Astronomical Society hides the published paper behind a paywall (DOI: 10.1093/mnras/stu2302, $28 for one day), you can read this University of Maryland press release, the Baltimore Sun article, or the arXiv preprint (1410.8520) for more details.
Zombie galaxies must die
Galaxy Zoo’s 900,000 galaxy catalog let co-founder Kevin Schawinski and fellow researchers study “zombie galaxies”. Galaxies grow through a process of mergers with other galaxies that produce millions of young, hot, blue stars. Old galaxies in which star formation has stopped have a redder hue because most of the surviving stars are old, cool, and red. The zombies lie in between the two stages - they have stopped growing but star formation keeps going anyway. The paper published in the identified two process that may stop star formation. The massive black holes at a galaxy’s center kill some galaxies quickly as they destroy the dust clouds where stars form. The zombies, on the other hand, are dead but keep on going. They no longer grow through mergers, but new star formation continues until it exhuasts all of the galaxy’s dust clouds. While the paper is hidden behind the Monthly Notices of the Royal Astronomical Society paywall (DOI: 10.1093/mnras/stu327, $28 for one day), you can read this New Scientist article for more details.
Voorwerping the Universe: yellowballs
The previous two papers reflect the kind of research Galaxy Zoo was designed to support: astronomers use the massive catalog to answer questions about different kinds of galaxies. An unexpected outcome of crowdsourced projects, however, are the discoveries the volunteers themselves make. The first of these was Hanny's Voorwerp (voorwerp means object in Dutch). Volunteers use the project's forum to report strange objects they see in the images. As volunteers find more examples of a strange object, the project’s scientists conduct formal research to figure out what the object is.
The latest example of this volunteer discovery came from the Milky Way Project. Volunteers reviewing images of star-forming dust clouds from the infrared Spitzer Space Telescope saw strange fuzzy objects that they called “yellowballs”. The Milky Way Project’s scientists decided it was worth looking into and published their results in They think yellowballs are probably stars 10-40 times larger than the Sun that pass through the yellowball phase shortly after forming. The cloud of gas and dust immediately surrounding the star glows from the energy it absorbs. Once the young star’s intense solar wind blasts the surrounding gas and dust away, the yellowball disappears. The full paper is locked behind The Astrophysical Journal paywall (DOI: 10.1088/0004-637X/799/2/153, $9 purchase), but you can get more details from the Iowa State University press release.