Is there a classification called a "jellyfish galaxy"?

Interesting things
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http://legacysurvey.org/viewer?ra=175.3449&dec=-6.4813&zoom=13&layer=decals-dr5

…it would apply to this one! :slight_smile:

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There are jellyfish galaxies, but this doesn’t look like one to me. The already existing category of jellyfish galaxies are moving so fast against the intergalactic medium that they are leaving trails of hot gas and star formation behind and those strands look like tendrils of a jellyfish. They can usually be spotted fairly easily in Hubble imagery of large galactic clusters.

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… and I thought I had made it up! :slightly_smiling_face:

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My first post here.

Can anyone please give me a reference to “jellyfish galaxies”, one that they feel is reliable?

Also, does anyone have a few examples to hand, like a collection or something (one that you’d be willing to share)?

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Hi Jean!
This was a memorable one for me because it was in an image that contained at least 5 examples (!) all by itself.

I processed an image of this cluster, and the bonus 5th one is annotated at the leftmost side of the image (click through to Flickr for annotations):
Imgur

My personal favorite example is ESO 137-001. I think there may be closer or brighter specimens farther from the galactic plane, but this one is relatively well studied and there are Hubble and Chandra datasets readily available for it.

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Thanks geckzilla! :slight_smile:

Very informative. It seems they are (all?) basically spiral galaxies (disk, bulge, arms; bar? ring??), albeit rather distorted ones. And not elliptical, irregular, or lenticular.

(Not sure about “click through to Flickr for annotations”; maybe not enough coffee this morning?) (and I’m still getting the hang of this forum)

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I had linked to my Flickr gallery, which allows me to add annotations that become visible when you hover the image, but this forum converted my link into a full image. Upon further inspection I now realize that it also converted the link into a direct image link instead of the gallery view, which is why you’d never be able to see the annotations. Drat! Perhaps the following link will work:
Test link

Regarding the morphology of jellyfish: Yes, now that you mention it, they do all seem to be at least disks, if not all spirals. I’ll have to keep a lookout for any deviants.

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Thanks! :slight_smile:

Yes, the link worked; very cool image+annotation!

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wow I can almost drown in such an image, great work!

PS. the annotations aren’t meant to be links to larger images of those objects are they?

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Nah, they don’t link to larger images. It’d be nice, but that’s not how Flickr works. Gotta do it the hard way by downloading the original size image from the download page and then panning and zooming to them manually.

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Is there a high resolution image of the X-Ray activity in this cluster?

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One of the figures in the paper includes contours from Chandra:
https://arxiv.org/abs/1204.1052

There’s also this image from the Chandra website:
http://chandra.harvard.edu/photo/2011/a2744/

The x-ray data are the same as other parts of the spectrum in that you kind of need to filter it down to the appropriate energy level to see certain things, so the contours from the paper are probably more appropriate for seeing where the x-rays and the jellyfish overlap. Some of them don’t seem to have much x-ray emission, though. Then again, the cluster itself is kind of flooding over any fainter sources.

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Here is another one from the HSC

DgyrJtvU0AAqRVu?format=jpg1200×387

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Hey Monkey, I think that one is not a jellyfish but rather more of an umbrella galaxy, which happens when an elliptical is disturbed by a smaller, more compact galaxy that has oscillated back and forth within while merging and left “umbrella” shaped crescents of stars on either side. I wonder if that inner blueish ring is strong gravitational lensing. Hard to say. Very interesting specimen either way.

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Hmm yeah by the looks of it you’re probably right, but I’m not gonna argue with Johnny Greco (image poster) here :wink:

And at the end of the day it’s just humans naming things, depending on definitions which sooner or later will turn out to need revisions / lead to useless terminology bickering (planets / dwarf planets etc.).

:wink:

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Late to this amazing image! The HSC one seems to suggest a point-source nucleus surrounded by a ring seen at pretty high inclination … which would suggest that there was, once, a disk … so maybe originally a lenticular?

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Astrobites 12-12-2018

The Properties of Simulated Jellyfish