Radio Galaxy Zoo Talk

ARG0003g7e

  • Dolorous_Edd by Dolorous_Edd

    SDSS J104122.17+052437.0 is a star according to spectrum, yet there is clear extension visible

    The source of radio emission is a background source? and we are looking at overlap star + whatever?

    enter image description here

    enter image description here

    Posted

  • KWillett by KWillett scientist, admin, translator

    That's really interesting (and odd). Spectrum is consistent with a star, but that extension to the lower right looks real - I see it in at least 4/5 bands. Might be a second star, either a true binary or a fortuitous overlap.

    ugriz SDSS images

    Posted

  • JeanTate by JeanTate

    Very cool!

    I think it's a chance alignment; there's a local (in our own galaxy) foreground star that has nothing to do with the extended optical emission or the radio emission. The source of the radio emission may be the extended optical emission; from its color and size, I think it's fairly local, z < ~0.3, more likely ~0.1. If it's a type 2 AGN, it could be too faint to show up in the SDSS spectrum; or it could be 'hidden. Is it a known x-ray source?

    Posted

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

    What IR data can tell us? It is clearly visible in WISE bands 1 - 2, but seems to be nothing in bands 3-4

    Here is NED entry

    And it is listed in Atlas of Radio/X-Ray Associations (ARXA) as ARXA J104122.1+052437

    Posted

  • JeanTate by JeanTate

    If I had more time (and energy 😦), I'd run this through GALFIT*. Removing the PSF star would likely show the underlying galaxy more clearly, and perhaps even hint at its morphology (g-band vs r-band should be most interesting).

    What IR data can tell us? It is clearly visible in WISE bands 1 - 2, but seems to be nothing in bands 3-4

    The foreground star is, spectroscopically, an M0; that means it should be clearly visible in at least WISE band 1 (3.4μ), and probably band 2 (4.6μ); such a star would not normally be visible in band 3 (12μ) or band 4 (22μ) unless it was surrounded by a debris disk (as far as I know anyway). A detailed quantitative analysis might hint at the presence of an AGN, but as nothing of such an AGN shows up in the SDSS Legacy spectrum**, I think it'd be a long shot for the WISE data to show something obvious.

    *Some time ago, I bought myself a Linux box, taught myself Linux, installed GALFIT, taught myself how to use it ... this Zooniverse Letter contains some examples of the analyses I did using GALFIT

    **I had a closer look; I see no hint of any narrow emission line near where a z ~0.05-0.3 H-alpha, [OIII], or [OII] would be; as these are the strongest AGN emission lines (in the relevant wavelength range), this suggests whatever such emission lines are there, they're buried in the noise.

    Posted

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

    **I had a closer look; I see no hint of any narrow emission line near where a z ~0.05-0.3 H-alpha, [OIII], or [OII] would be; as these are the strongest AGN emission lines (in the relevant wavelength range), this suggests whatever such emission lines are there, they're buried in the noise.

    Update: there may be the slightest of hints of a z=0.16 system, [OIII]5008 and [OIII]4960 in particular

    Posted