Long wispy spiral arms at the edge of the halo?
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by
dindon
Anyone know what's going on here? Is this just another kind of spiral arm? Is this what they mean by the "lens or arc" odd feature? (Unfortunately the example image for that is broken right now.)
Posted
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by
Budgieye
moderator
These are very long spiral arms. They are so long that they are nearly forming a ring.
They are not an arc. Arcs are wrapped around the galaxy, not sticking off the one side. Also, these galaxies are unlikely to have any arcs around them, because they don't have enough mass to be a lensing system. The few examples of possible lenses around spirals are when the spiral has been viewed edge-on, and the arcs are near the nucleus.
Some examples are here
3.9 Gravitational lenses http://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0000wrb?page=3&comment_id=53d8b966db90c7620200110c
Posted