Galaxy Zoo Talk

Is this gravitational lensing? Also, what is just right to the nucleus?

  • ramberts by ramberts

    There is no known galaxy that could be overlap, I know that doesn't mean one doesn't exist...because I have seen some that are in Hubble that don't have an Arcmin that corresponds to NED but it's very very rare. I'm assuming it's a galaxy...but I'd think it would be in NED. Jets I've seen from cores aren't off center like this, usually right in the middle. Could it be some sort of emission line?

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  • Capella05 by Capella05 moderator in response to ramberts's comment.

    Hi @ramberts,

    I have been pondering over this image for several hours, I will tackle the question of it being a gravitational lens and leave any other additional unanswered questions up to others 😃

    Firstly, NED is not always up to date - so gaps in the data are too be expected, especially when we are observing such distances. That is one of the reasons why the classifications we do at GZ are so important!

    Onto whether this is a gravitational lens - I personally think it is a 'convincing imposter'.

    Although I do not think it is a lensed galaxy, there are also a few features that strike me as having fairly convincing lensed like features - hence my reluctance in posting a reply. Before we begin - even though this galaxy is in the SDSS footprint, there is not much data to go on. So all my observations are based on analysing the image itself, without resorting to any external sources (as one would do when classifying 😃 )

    • The blue 'satellite' galaxy on the left is not lensed - too diffuse in shape and does not follow the same pattern as the other blue arcs.
    • The arc north initially captured my attention - sharp features, nice shape and it is nicely aligned to the galaxy - but it is somewhat angular.
    • Looking on right hand side - we have multiple blue bands that are more indicative of star formation than lensing. They are also very diffuse, not something we would expect to see in this type of lensing.
    • We seem to have clumps of smaller objects just outside the 'ring' with a similar colouring - suggesting they are related. So I am more likely to go with star formation as the most likely cause.
    • Also, I have concerns about the mass of galaxy. It looks a bit lightweight to cause this level of lensing, and at the radius it is visible.

    Sorry I can't answer all your questions - I am a bit swamped at the moment!

    Julianne

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  • Budgieye by Budgieye moderator

    Regarding galaxy jets, we can only see jets in 6 of the nearest galaxies, and these are not near. see

    3.6 Relativistic jets http://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0000wrb?page=3&comment_id=53d8b92adb90c76710000f93

    Grey streak- when I am lost, I blame cosmic rays. Perhaps a cosmic ray was "cut out" and the empty place repainted in something matching, which is approximately what the software does.

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  • Capella05 by Capella05 moderator

    Quote from @Budgieye

    Grey streak- when I am lost, I blame cosmic rays. Perhaps a cosmic ray was "cut out" and the empty place repainted in something matching, which is approximately what the software does.

    I thought the same, but after looking at the image for ages, couldn't it be a foreground dusty edge-on slightly overlapping the elliptical?

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  • Budgieye by Budgieye moderator

    Yeah, a good point, if a dust lane can produce a dark streak, why not an elliptical galaxy?

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  • Capella05 by Capella05 moderator

    Ooops, I should of clarified my post better!

    I think there is a dusty edge-on galaxy slightly overlapping the central elliptical galaxy, therefore creating the 'grey streak'.

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  • Capella05 by Capella05 moderator

    I have asked Dr Phil to have a look - Clean eyes 😃

    If my assumption that we also have a foreground edge-on galaxy in the mix, it could account for the angular nature of the northern arc.

    All just conjecture- and I am still not that convinced..

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  • ramberts by ramberts

    wow, lots of great feedback, thanks guys! 😃

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  • drphilmarshall by drphilmarshall scientist

    The very thin arc does look a little lens-ey - but I'm suspicious because of the other things going on in the picture. That looks like a small galaxy merging in the core (ie superposed along the line of sight, so the blue features could be some other signs of merger activity in the system. That's not to say the arc couldn't also be due to lensing! Circumstantial evidence, I guess. I'd give it a possible/probable, and would not ne sure at all about spending lensing follow-up time on it.

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  • ramberts by ramberts

    Very interesting, thanks for the follow up!

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