Galaxy Zoo Talk

Morphology question: is this galaxy a bless Sc?

  • JeanTate by JeanTate

    SDSS J171455.01+353113.6:

    enter image description here

    "bless" as in "bulge-less". Also, would you say it's a classic 'grand design' two-arm spiral? Or does it have a small bar?

    And how would you decide if it's more an Sd than an Sc (I know it's not an Sb; the bulge is far too small, and the arms too blue and well-developed)?

    Posted

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

    "bless"??

    What do you think it is?

    I'd call it SABc in a simplified version of deVaucouleur's (sp?) classification scheme, based on comparing the DR10 image to Figure 8 in Buta's monograph.

    NED shows no detailed classification for IC 1249 and it seems to be in neither published version of Galaxy Zoo.

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

    Thanks mlpeck.

    "bless" is my word; it's catchier and shorter than "bulgeless", the staid normal term. šŸ˜›

    I've just re-read a few GZ blog posts on bless spirals, such as Why Iā€™m at WIYN: Mergers and Bulgeless Galaxies. Sure, you'd need to run something like GALFIT over the SDSS photometric data to be certain, but visual comparison suggests - to me, intuitively - that SDSS J171455.01+353113.6* does not have a bulge (or one that is too small to resolve). Yet it's not one of the 15 in Simmons+ (2013).

    *curiously 0.031' distant from IC 1249, per NED

    Posted

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

    SDSS J171455.01+353113.6* does not have a bulge (or one that is too
    small to resolve). Yet it's not one of the 15 in Simmons+ (2013).

    *curiously 0.031' distant from IC 1249, per NED

    This is IC 1249. For some reason the cataloged position is offset a few arc-seconds from the nucleus. If the SDSS explore tool within navigate is right it doesn't seem to have been in either of the first two iterations of Galaxy Zoo, so it wouldn't have been a candidate even if it met Simmons et al.'s other selection criteria. Just squinting at the spectrum I'm not sure there's an AGN there, which weeded out the huge majority of their initial candidates.

    Here by the way is a zoomed out finder chart image for NGC 4535, which Buta used as his prototype SABc galaxy. Do they look similar? I'd say yes.

    I take it this is a radio source.

    enter image description here

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