American Friends of Tel Aviv University | Royal Astronomical Society | 2018 Nov 19
Discovery illuminates how and why galaxies disappear, say TAU researchers
A team of astronomers from Israel, the U.S. and Russia have identified a disrupted galaxy resembling a giant tadpole, complete with an elliptical head and a long, straight tail, about 300 million light-years away from Earth. The galaxy is one million light-years long from end to end, ten times larger than the Milky Way.
“We have found a giant, exceptional relic of a disrupted galaxy,” says Dr. Noah Brosch, of The Florence and George Wise Observatory at Tel Aviv University’s School of Physics and Astronomy, who led the research for the study.
When galaxies are disrupted and disappear, their stars are either incorporated into more massive galaxies or are ejected into intergalactic space. “What makes this object extraordinary is that the tail alone is almost 500,000 light-years long,” says Prof. R. Michael Rich of the University of California, Los Angeles. “If it were at the distance of the Andromeda galaxy, which is about 2.5 million light-years from Earth, it would reach a fifth of the way to our own Milky Way.” ...
According to the study, the giant “tadpole” was produced by the disruption of a small, previously invisible dwarf galaxy containing mostly stars. When the gravitational force of two visible galaxies pulled on stars in this vulnerable galaxy, the stars closer to the pair formed the “head” of the tadpole. Stars lingering in the victim galaxy formed the “tail.” ...
Hickson Compact Group 98: A Complex Merging Group with
a Giant Tidal Tail and a Humongous Envelope ~ Noah Brosch et al
- Monthly Notices of the RAS 482(2): 2284 (Jan 2019) DOI: 10.1093/mnras/sty2717