| 25th of August 2015 |
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| Kathryns Wheel: A spectacular galaxy collision discovered in the Galactic neighbourhood |
| by Quentin Parker (University of Hong Kong) |
|
Parker et al.
(2015) report the discovery of the closest collisional ring galaxy to the
Milky Way. Such rare systems occur due to "bulls-eye" encounters between two
reasonably matched galaxies. The recessional velocity of about 840 km/s is
low enough that it was detected in the AAO/UKST Survey for Galactic Halpha
emission (shown in red colors above). The distance is only 10.0 Mpc and the
main galaxy shows a full ring of star forming knots, 6.1 kpc in diameter
surrounding a quiescent disk. The smaller assumed "bullet" galaxy also shows
vigorous star formation. The spectacular nature of the object had been
overlooked because of its location in the Galactic Plane (b = -7.9 degr) and
proximity to a bright star and even though it is the 60th brightest galaxy
in the HI Parkes All
Sky Survey (HIPASS). -
The galaxy is known as ESO179-IG013 and HIPASS J1647-57 (Koribalski et al. 2004). Reference: Parker, Zijlstra, Stupar, Cluver, Frew, Bendo, Bojicic 2015, MNRAS, in press |
