<p>This is almost certainly an example of a <a href="https://ned.ipac.caltech.edu/level5/Sept01/Appleton/frames.html" rel="nofollow noreferrer">collisional ring galaxy</a>. It's listed as such (under the alternate name AM 0417-391) in the catalog of <a href="https://ui.adsabs.harvard.edu/abs/2009ApJS..181..572M/abstract" rel="nofollow noreferrer">Madore et al. 2009</a>; here is a panel showing the galaxy from one of their figures:</p>
<p><a href="https://i.sstatic.net/tks1b.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/tks1b.png" alt="DSS image of AM 0417-391 from Madore+2009" /></a></p>
<p>Image (probably from the Digitized Sky Survey) of AM 0417-391 = LEDA 14884), taken from Figure 5 of Madore et al. (2009). &quot;RN&quot; = &quot;ring nucleus&quot;; &quot;C<em>n</em>&quot; = possible &quot;companion&quot; galaxies -- though some of these are in this case parts of the ring.</p>
<p>These are thought to be the result of a smaller galaxy colliding more or less head-on with a larger disk galaxy. The smaller galaxy passes through (so these are sometimes called &quot;drop through&quot; collisions), but leaves behind a pronounced &quot;ripple&quot; in the gas, which becomes concentrated in an expanding ring and forms stars at a high rate; this shows up as a ring of gas and bright, young stars. Since most such collisions will be off-center (i.e., the smaller galaxy won't pass through the exact center of the bigger galaxy), the ring will be asymmetric, as is clearly the case for LEDA 14884.</p>
<p>These are very rare systems; Madore et al. (2009) quote an estimated frequency of 0.01% of galaxies in the local universe being collisional ring galaxies.</p>

CC BY-SA 4.0
2021-03-12T12:59:02.800Z
2021-03-12T14:43:32.323Z
2021-03-12T14:43:32.323Z
Peter Erwin
<p>A <a href="https://noirlab.edu/public/es/images/iotw2110a/" rel="nofollow noreferrer">new image</a> of deep space was released yesterday, showing tons of galaxies. One in particular (named &quot;LEDA 14884&quot;) looks very puzzling (like an ear), zoomed in below:</p>
<p><a href="https://i.sstatic.net/ECWJO.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/ECWJO.png" alt="enter image description here" /></a></p>
<p>Article says it's a ring-shaped galaxy. Is there a more precise characterisation in terms of well-known galaxy typologies (irregular perhaps)? Perhaps the angle is confusing it's otherwise usual shape?</p>

<galaxy><identify-this-object>
What type of galaxy is LEDA 14884?
luchonacho
# What type of galaxy is LEDA 14884?

(Asked by: username_0 on 2021-03-12)

A [new image](https://noirlab.edu/public/es/images/iotw2110a/) of deep space was released yesterday, showing tons of galaxies. One in particular (named "LEDA 14884") looks very puzzling (like an ear), zoomed in below:

[![enter image description here](https://i.sstatic.net/ECWJO.png)](https://i.sstatic.net/ECWJO.png)

Article says it's a ring-shaped galaxy. Is there a more precise characterisation in terms of well-known galaxy typologies (irregular perhaps)? Perhaps the angle is confusing it's otherwise usual shape?

**Tags:** galaxy, identify-this-object


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## 1 answers

### Answer by username_1 on 2021-03-12. Score: 4 | Accepted answer

This is almost certainly an example of a [collisional ring galaxy](https://ned.ipac.caltech.edu/level5/Sept01/Appleton/frames.html). It's listed as such (under the alternate name AM 0417-391) in the catalog of [Madore et al. 2009](https://ui.adsabs.harvard.edu/abs/2009ApJS..181..572M/abstract); here is a panel showing the galaxy from one of their figures:

[![DSS image of AM 0417-391 from Madore+2009](https://i.sstatic.net/tks1b.png)](https://i.sstatic.net/tks1b.png)

Image (probably from the Digitized Sky Survey) of AM 0417-391 = LEDA 14884), taken from Figure 5 of Madore et al. (2009). "RN" = "ring nucleus"; "C*n*" = possible "companion" galaxies -- though some of these are in this case parts of the ring.

These are thought to be the result of a smaller galaxy colliding more or less head-on with a larger disk galaxy. The smaller galaxy passes through (so these are sometimes called "drop through" collisions), but leaves behind a pronounced "ripple" in the gas, which becomes concentrated in an expanding ring and forms stars at a high rate; this shows up as a ring of gas and bright, young stars. Since most such collisions will be off-center (i.e., the smaller galaxy won't pass through the exact center of the bigger galaxy), the ring will be asymmetric, as is clearly the case for LEDA 14884.

These are very rare systems; Madore et al. (2009) quote an estimated frequency of 0.01% of galaxies in the local universe being collisional ring galaxies.


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