Galaxy Zoo Talk

Undiscovered collisional ring?

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Undiscovered collisional ring galay pair or simply interaction disturbance?

    Not in any ring / collisional ring catalogue or reference.

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    SDSS J121447.45+140543.8

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    SDSS J121446.34+140532.9

    Posted

  • mlpeck by mlpeck

    I think that's a likely #overlap, with the large galaxy a Virgo cluster member and therefore well in the foreground. It doesn't appear to be in the EVCC however, but it wouldn't be with an apparently firm redshift of z=0.08.

    It might be possible to find evidence for a composite spectrum with a z≈0 component, but I don't have the tools available at the moment.

    Edit: why do I think overlap?

    1. Ned gives conflicting size estimates, but take 16" semi major axis as correct. That would make its diameter 50kpc. at z=0.08 which seems implausibly large.
    2. It doesn't actually appear disturbed to me. I'd call it a loosely organized spiral with Hubble type something like SBdm.

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR in response to mlpeck's comment.

    Ah, my mind has been playing tricks with me, I see what you mean. Essentially it's "all the blue stuff is nearby, all the yellow stuff is faraway".

    Then the blue indeed starts to look more like a barred spiral. I associated the first yellow galaxy as nucleus of the blue stuff which makes it look like a highly inclined ring, with the second galaxy as 'culprit'.

    I guess I could've worked out the implausable size at that redshift but didn't think to check. If in the foreground yes that should definately have to show in the spectrum, with such a big blue thing (starforming?) in the front shouldn't that actually be very clearly visible in the spectrum as the two nucleï overlap?

    Thanks for the feedback.

    First galaxy seems to have an odd arc too, weird stuff.

    Posted

  • NGC3314 by NGC3314 scientist

    I incline to this being a close encounter which was off-center enough to form not a symmetric ring, but an eccentric and elongated one. I don't see any misplaced spectral features in either SDSS spectrum. This looks a lot like simulations of near-central encounters right down to the displacement ("flapping") perpendicular to the regional disk plane. (The spiral pattern makes more sense if on a shallow cone rather than a flat plane.) The famous Cartwheel collisional ring has a diameter about 50 kpc, so for a transient phase that's not outlandish.

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR in response to NGC3314's comment.

    Wow that would be really great, especially since it is so well visible yet unreferenced! I was indeed wondering about the absence of a foreground starforming galaxy in the spectrum, but then again I'm mostly a novice at spectra still..

    Thank you for the feedback and background info. Perhaps an interesting one for Alexei Moiseev or was it only polar rings?

    To top it off, here is the recently released DECaLS DR5 image, which indeed makes it look a bit more ring-like (or heart-shaped even), and DECaLS residuals;

    enter image description here enter image description here

    Posted