![]() As galaxies fall through these larger halos, the superheated intergalactic plasma between them removes their gas in a fast-acting process called ram-pressure stripping. ![]() “During their lifetimes, galaxies can inhabit halos of different sizes, ranging from masses typical of our own Milky Way to halos thousands of times more massive. For some time, astronomers have believed that galaxies are embedded in clouds of this invisible mass, which is believed to make up 27% of the known Universe.Īs Toby Brown – a researcher from the Center for Astrophysics and Supercomputing at the Swinburne University of Technology and the lead author on the paper – explained: While the SDSS provided multi-wavelength data on 10,600 satellite galaxies in the known Universe, ALFA provided data on the amount of neutral atomic hydrogen they contained.īy measuring the amount of stripping that took place within each, they deduced that the extent to which a galaxy was stripped of its essential gases had much to do with the mass of its dark matter halo. Credit: Natasha Hurley-Walker (ICRAR/Curtin)/Dr John Goldsmith/Celestial Visions.įor the sake of their study, titled “ Cold gas stripping in satellite galaxies: from pairs to clusters“, the team relied on data obtained by the Sloan Digital Sky Survey and the Arecibo Legacy Fast (ALFA) survey. ‘Radio color’ view of the sky above the Murchison Widefield Array radio telescope, part of the International Center for Radio Astronomy Research (ICRAC). At this point, they lose gas, much in the same way that a planet’s atmosphere can be slowly stripped away by the effects of Solar wind. This process is known as “ ram-pressure stripping“, which occurs when the force created by the passage of galaxies through the hot plasma that lies between them is strong enough that it is able to overcome the gravitational pull of those galaxies. According to their study, which appeared recently in The Monthly Notices of the Royal Astronomical Society, this mechanism may be responsible for the slow death we are seeing out there. And for some time, astronomers have been searching for the potential culprit.īut according to a new study by a team of international researchers from the International Center for Radio Astronomy Research (ICRAR) in Australia, the answer may have to do with the hot gas galactic clusters routinely pass through. This process is responsible for halting the formation of new stars, and therefore condemning these galaxies to a relatively quick death (by cosmological standards). All over the known Universe, satellite galaxies are slowly being stripped of their lifeblood – i.e. It’s what you might call a case of galactic homicide (or “galacticide”).
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