Radio Galaxy Zoo Talk

ARG00002po star galaxy radio source?

  • A1001 by A1001

    NVSS J091926+614954 -- Radio-source SDSS J091926.58+614954.0

    enter image description here

    Posted

  • JeanTate by JeanTate

    Strange. SDSS J091926.58+614954.0

    If it's a radio star (they do exist), it's a quite strong emitter.

    On the other hand, if it's a QSO (it is a UV source), it's a very bright one, and strange that no one has taken a spectrum of it.

    It could be an chance cosmic coincidence - a background QSO and a MW star on ~the same sightline - but somehow I doubt it.

    It should be in Gaia DR2; anyone know how to find out what's there?

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  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    It seems to move to me between DSS2 and SDSS DR9, GAIA DR2 in VizieR gives proper motion of pmRA -2.423 err 0.137 pmDE 3.024 err 0.192, which is in the apparent RA but not DEC. Perhaps so small to be insignificant.

    Also in the MORX catalog which associates this optical source with radio AND X-ray (next to your UV source find). Funnily MORX gives it a ''probability that this object is a QSO'' of 41%, and ''Probability that this object is a star 52% (6% galaxy).

    And some VizieR references about radio spectra? Don't know what to do with those.

    Also notable is that there is a lobe / arc visible in three different surveys at 7 o'clock (and at 10 o'clock?). Background or associated with object? Which itself is also unknown to be extragalactic or MW star.

    EDIT Is that lobe changing positions between surveys??

    SDSS, MzLS+BASS (DECaLS viewer) Panstarrs images below. Panstarrs image can also be found HERE

    enter image description hereenter image description hereenter image description here

    LINK for DECaLS MzLS+BASS

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  • JeanTate by JeanTate

    Thanks Ghost_Sheep_SWR! 😃

    I asked about this over in the CosmoQuest Forum (link), and ngc3314 was kind enough to reply:

    Gaia DR2 lists it with parallax 0.22+/0.11 milliarcseconds, not correcting for the parallax bias found from, for example, known high-redshift objects (which would make the significance of this parallax even more underwhelming ). For a single source, a quick route to the Gaia DR2 numbers is entering coordinates at the top of this VizieR form.

    The SDSS colors don't make sense for a single star, with a huge drop between r and i superimposed on a reddish continuum, or emission affecting both r and i bands. In fact, r-i=-0.96 would be odd even for a typical quasar anywhere up to z=6 (which could be why the object evaded being included in ay of the SDSS samples so far). Taking wild guesses, could be H-alpha emission from something at modest redshift? (But it would be hard to hide the galaxy). GALEX shows good detections in both near- and far-UV bands, much brighter in NUV, which mitigates against such a high redshift that Lyman absorption wipes out the UV flux.

    To quote Alice, curiouser and curiouser 😄

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  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    My pleasure, I love astro mysteries 😃

    Quite the detour, nice of NGC3314 to take a look. I’ll check later if I can spot motion of the object / lobe. So there is optical, radio, UV and X-ray emission, anything missing from the spectrum? 😉 havent checked WISE yet.

    And if there IS a ‘radio spectrum’ in (from VizieR) I’m sure the sciteam can make sense of it.

    Posted

  • Dolorous_Edd by Dolorous_Edd

    I would recommend to do an overlay , from the quick look it doesn't look that the radio source is perfectly on top

    It looks offseted from star

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  • JeanTate by JeanTate

    Thanks for your inputs, and interest!

    If it is a QSO, it's a strange one ... check out the WISE colors (yes, it is a WISE source; it'd be astonishing if it weren't).

    It has been observed at other times, in various radio bands; as far as I know it's not a (radio) variable - so making it an unusual radio star if star it is (radio stars are often flare stars, or x-ray binaries, or ...) - and its radio spectral index unremarkable (this courtesy of HAndernach, "private communication").

    If only we had a spectrum! 😉

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Found nothing of interst so far, neither were the MzLS+BOSS images really helpful, so this is about the last thing I can add.

    Reduced the object in SDSS z band as far as possible to a couple of pixels to get a better feel of the center, contour overlays from FIRST using Aladin Desktop. Depending on how reliable this method is it does indeed seem that the radio source is offset from the bright object's centerpoint. So maybe it is a QSO and MW star aligned in our line of sight.

    enter image description here

    Posted

  • A1001 by A1001

    at the bottom of the object there is a green area & there are 3 white dots.

    at the top there is a blue arm.

    looked at HUBBLE & CHANDRA images could not find a x ray, blue star or QSO similar image.

    the object is unique.

    is there a way to enlarge the image.

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

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  • Dolorous_Edd by Dolorous_Edd

    at the bottom of the object there is a green area & there are 3 white dots

    pretty common, actually, for bright stars in SDSS, I consider them usually to be artifacts from oversaturation, IMO

    they have this sort of green fluff around

    at the top there is a blue arm.

    diffraction spike

    Posted