?Tidal Debris
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insaneAyesh
Can someone pls clarify what is Tidal Debris. From the description(text) I have an understanding but the pictures used to iluuminate actually confused me. Pictures of examples of mergers with Tidal debris and without were not clear. Im not inclined to classify till Im clear 😕. Thank you all!
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KWillett
scientist, admin, translator
That's a really good question. "Tidal debris" refers to extensions of stars and/or gas that have been ripped away from a galaxy under the influence of some gravitational interaction. In particular, we're looking for features that aren't symmetric; this could include things like small bulges of light at the edge of a galaxy, bridges between two galaxies, or long streams. Tidal debris is often going to be very faint, but you're looking for anything close to the edge of the galaxy that doesn't look like a symmetric feature.
The reason we separate this from the "mergers" question is that you don't always see both in the same galaxy. For example, you might have two galaxies that have already completely merged their centers together, but where you still see streams of gas and stars that form tidal debris. That tells us that the galaxy had a merger sometime in the past, which is what the science team wants to study. You might also see tidal debris caused by a distant galaxy that's out of the image view, for example. You can sometimes also have mergers without tidal debris; the galaxies are approaching each other, but haven't stripped off any of the gas and stars yet. And often you'll see both merger AND tidal debris, which is what I usually think of as a "classic" merging system.
I'm writing a longer blog post (with lots of images/examples) on mergers and tidal debris for next week. I'll post it on Talk as well once it's done.
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insaneAyesh
Many thanks! I have a better grasp now and look forward to the blog.
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