Radio Galaxy Zoo Talk

ARG00008v4 - double lobe with 'local' SBc host? Also, WISE offset??

  • JeanTate by JeanTate

    SDSS J132809.31+571023.3, z_ph 0.035±0.0348/0.035±0.0238 (!) looks like a fairly typical ~face-on late barred spiral (though a neiboring PO may be the nucleus):

    enter image description here enter image description here

    The slightly asymmetric #doublelobe (or #hourglass if you prefer) radio structure seems consistent with a core very close to the nucleus of SDSS J132809.31+571023.3 (position-wise; strangely this galaxy does not seem to have an NGC/IC or UGC ID):

    enter image description here

    But when you add WISE data, it gets very strange indeed ...

    enter image description here

    Magenta contours are WISE band 1 (3.4μ); quite unremarkable (more or less follows the bar, and other extended emission is as expected (galaxy to the NE, bright star - with diffspikes - to the NW).

    But while the WISE band 3 (12μ) emission is similar to the band 1 emission in that it also follows the bar, there's other emission that seems strange (yellow contours):

    enter image description here

    For example, what's the extended emission to the SE and NW? And why does the band 3 emission also seem to trace the SW radio jet/lobe?

    Finally, the WISE band 4 (22μ) - lime contours - really messes with your mind:

    enter image description here

    Seems that it's offset from the band 1 and band 3 emission, not only for the galaxy in the center, but also the one in the NE. Some of the 22μ emission seems similar to the 3.4μ and 12μ emission; some not.

    Finally, FIRST contours overlaid on a rather heavily processed Luptonized WISE canvass (bands 1, 3, and 4) shows many of the above expected and strange/unexpected features:

    enter image description here

    The image in this post was created from sources, and using methods, described in this RGZ Talk post. The object at the center of the image is SDSS J132809.31+571023.3.

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  • DocR by DocR scientist

    I'll point this out to the people who know spirals better. Definitely worth tracking down the strange offsets.

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

    Thanks DocR.

    I went to IRSA, plugged in the location of SDSS J132809.31+571023.3, (202.0388, 57.1732), and captured some ATLAS images as screenshots. The cyan circle center is that location. Here's what I got (cropping screenshots, accurately and consistently, is not one of my strong skills!); band 1, band 3 (first line); band 4, multi-band (second):

    enter image description here enter image description here

    enter image description here enter image description here

    These WISE images use the default scale/stretch parameters, but they are good enough to show pretty much all the features in the various overlay images above.

    As for Dolorous Edd's suggestion that there might be a background galaxy, the true host of the FIRST hourglass radio emission, well a GZ forum OOTD I did might be of interest (click here). One curious thing however: if there's a background AGN, now come it's so faint at 12μ and 22μ?

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  • mini.mintaka by mini.mintaka scientist

    This is weird and confusing!! ... I don't know enough about the WISE data to comment... any IR experts around? 😃

    The optical image looks odd... is it post-merger?

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  • JeanTate by JeanTate

    Zooming out somewhat, and with the same overlay color scheme (magenta=band1/3.4μ, lime=band4/22μ):

    enter image description here
    enter image description here

    3.4μ IR emission detected by WISE nicely coincides with SDSS objects; in particular, the nuclei of the three ~NE-SW spirals are local 3.4μ maxima.

    But for the 22μ IR emission detected by WISE, there's an offset - between the nuclei and local 22μ maxima, and between 3.4μ and 22μ maxima - for two of the three spirals:

    enter image description here
    enter image description here
    enter image description here

    The images in this post were created from sources, and using methods, described in this RGZ Talk post. The object at the center of the images is SDSS J132809.31+571023.3.

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  • Dolorous_Edd by Dolorous_Edd

    I am just curious could this be considered SDRAGN? or emission is too weak for this?

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  • JeanTate by JeanTate in response to Dolorous Edd's comment.

    If the doublelobe emission is indeed from the z~0.035 somewhat messy, two-arm barred spiral, then it would be (very?) unusual, irrespective of its radio luminosity (well, IMHO anyway).

    I am working on answering mini.mintaka's question, and getting more info about this apparent host. In any case, I think it's a most interesting find, well done! 😃

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  • rad_astronomer by rad_astronomer scientist

    Hi Jean, this is a very interesting source. Clearly a small doublelobe #hourglass in a barred spiral. Interesting in of its self.

    The WISE results are possibly explainable as follows. The 12um and 22um bands are a lot less sensitive than 3.4um images by a factor of around 20 and 100 respectively. So a strong detection at 3.4um can be very low signal to noise at 12 and 22 um (as seems to be the case here looking at the contours and the grayscale - btw I would not put too much weight on the lowest contour at 12/22um). Furthermore, the resolution at longer wavelengths is also obviously worse (larger by a factor proportional to the ratio of the wavelengths). As positional errors are proportional to the resolution over the signal to noise then it is possible this result could just be a result of these two factors. We would have to look at the actual fluxes to be sure.

    One interesting thing is a even a weak detection at 12 and 22um could mean a lot of hot dust heated AGN.

    cheers, Nick

    Posted

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

    Thanks rad_astronomer/Nick!

    How common is it to describe WISE IR sources in terms of their colors (e.g. (band1-band2), (band4-band3), that sort of thing)?

    btw I would not put too much weight on the lowest contour at 12/22um

    I agree. But how do you work out what is the lowest contour that likely is reliable? As the threshold (0-th contour) is an input in my Python program, I can set it to any value within quite a large range. At the moment I use the same method for radio (e.g. FIRST, NVSS) as WISE (and also DSS), an input number of times the estimated sigma of the data in the field (estimates in a fairly robust way).

    We would have to look at the actual fluxes to be sure.

    Is there a reliable source for these fluxes?

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  • ivywong by ivywong scientist, admin in response to JeanTate's comment.

    WISE colour-colour diagnostic diagrams are commonly used in similar ways to BPT diagrams in the optical (ie. to differentiate between star-forming and AGN-dominated emission). E.g. Wright et al 2010, Cluver et al 2014 etc.

    The WISE catalogues have been published and there may be old IRAS measuerements as well. So you can look those up for a handle on the expected fluxes. I don't think that NED has included the WISE catalogues and measurements yet though. 😦

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  • Dolorous_Edd by Dolorous_Edd

    From the looks of it, there are some xrays fluxes available for this target

    enter image description here

    For more details

    http://isdc.unige.ch/heavens/

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  • DocR by DocR scientist

    Not sure I understand the comment about background galaxy. Definitely unusual, but looks like very disturbed barred spiral with likely double radio source, unless it's a random superposition. FIRST contours over SDSS g

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