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Ha regions in elliptical galaxies?

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Just curious if anyone has imaged elliptical galaxies in Ha and seen structure.
Thanks.
Last edit: 5 years 2 months ago by kamisan.
5 years 2 months ago #35192

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Yes. Check out my pictures. Although I have to warn you, they are not the best, since I am shooting from the middle of a large city, but they make the point you are asking. I think M81 is the last one I uploaded.
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5 years 1 month ago #35257

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Sorry to be pedantic but M 81 is not an elliptical galaxy ;-)
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5 years 1 month ago #35262

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Looks fairly elliptical to me, Wouter...:P

At least at that projection angle.

At any rate, I was interpreting the question to mean whether it was possible to image Ha regions in distant objects outside the Milky Way. That should be independent of the shape of the galaxy, whether elliptical, helical, artesian or surreal and designed by Dali.
5 years 1 month ago #35266

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I meant like these Type 'E' Elliptical and Spheroidal Galaxies:
cseligman.com/text/devaucouleurs.htm

Thanks all.
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5 years 1 month ago #35267

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Well, elliptical galaxies are known to have close to no gas or dust but there are exceptions.

EDIT: my post crossed the one of Kamisan.
Last edit: 5 years 1 month ago by Wouter van Reeven.
5 years 1 month ago #35268

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Well, in that case I have to revise my answer, too:

Ex nihilo, nihil fit!
5 years 1 month ago #35269

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I would say it is worth an experiment. I bet that some of these galaxies could have interesting Ha structures, but probably not all. I have tried a few galaxies in Ha and found some very interesting Ha regions. Particularly nice ones are of course the closer galaxies with larger angular size including Andromeda, M33, and the Pinwheel. It is always interesting to see the Ha regions pop out of a galaxy when an L exposure shows just spiral arms or just a uniform star cloud. It really would not take long to take one ha exposure of each of the galaxies that you think could be interesting, and then to use that initial experiment to sort the galaxies into ones that you don't want to pursue further and ones that merit more images.
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5 years 1 month ago #35274

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Yes, this sounds like a worthwhile endeavor. What is needed is a way to quantify the amount of Ha structures on a scale from, say, 0 to 5 where 0 is devoid of structures and 5 is abundant. Then see if there is a correlation between abundance and morphology.

Thanks.
5 years 1 month ago #35275

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I would have thought that the Hubble images would also show you that. Have you searched that catalogue and analyzed the available images? I would assume that Hubble has surely imaged most if not all those galaxies that are visible with our far more inferior equipment, so that data should be available (I would think).

If it is, please post a link to it here.

Thanks for starting this interesting thread!

Best

Jo
5 years 1 month ago #35279

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I am at the Hubble Legacy Archive. I have searched for a dozen or so Type E galaxies by NGC designation. All have been imaged in wideband. To do an exhaustive search I would need to construct a "position list" file to upload. I will work on that. So far it seems that narrowband is not commonly used for these targets. Not giving up yet!
5 years 1 month ago #35295

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From Wikipedia:

H II regions can be observed at considerable distances in the universe, and the study of extragalactic H II regions is important in determining the distance and chemical composition of galaxies. Spiral and irregular galaxies contain many H II regions, while elliptical galaxies are almost devoid of them. In spiral galaxies, including our Milky Way, H II regions are concentrated in the spiral arms, while in irregular galaxies they are distributed chaotically. Some galaxies contain huge H II regions, which may contain tens of thousands of stars. Examples include the 30 Doradus region in the Large Magellanic Cloud and NGC 604 in the Triangulum Galaxy.

en.wikipedia.org/wiki/H_II_region
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5 years 1 month ago #35296

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