Radio Galaxy Zoo Talk

ARG00011fo - M class star almost overlapping the QSO host?

  • JeanTate by JeanTate

    SDSS J152039.69+421111.1 has a very nice, clean z_sp 0.485 spectrum. However, there's what looks like a red (M class?) star almost overlapping it:

    enter image description here

    It's so close it should show up in the spectrum, but I can't see anything in it which looks like a z ~0 M class star, can you?

    If it's not a foreground star, what is the red thing?

    Posted

  • ivywong by ivywong scientist, admin

    I am not sure what the red object is but the fibre covers both blobs fully and so the dominant emission from both blobs is from the QSO. Whether the red object is affiliated to the QSO is unclear due to the angular resolution limit of the SDSS/WISE observations. Hope this helps.

    Posted

  • 1001G by 1001G

    A amateur question. From NED.

    *B3 1518+423 15h20m39.6s +42d11m09s G >30000 z 0.484000 is that the QSO?

    GALEXASC J152039.70+421112.0 15h20m39.7s +42d11m12s UvS is that the STAR?

    Posted

  • Dolorous_Edd by Dolorous_Edd

    Reminded me

    http://radiotalk.galaxyzoo.org/#/boards/BRG0000006/discussions/DRG00002k9

    For B3 1518+423

    References in NED

    Posted

  • JeanTate by JeanTate in response to 1001G's comment.

    Aaaand here's this ordinary zooite's reply!

    *B3 1518+423 15h20m39.6s +42d11m09s G >30000 z 0.484000 is that the QSO?

    In a word, yes. The offset is ~2.5", which is well within bounds, given that the radio source is extended and has a complex shape (the radio positions are, I think, produced by either finding the centroid of the emission, or estimating where the peak is).

    GALEXASC J152039.70+421112.0 15h20m39.7s +42d11m12s UvS is that the STAR?

    Yes, it could be. Or it could be the same source. I don't think GALEX can - reliably and robustly - pin down the location (RA, Dec) of sources to less than 1" (but I could be wrong). NED puts this UV source at ~0.9" from SDSS J152039.69+421111.1.

    Hope this helps, and please, keep the questions coming! 😃

    Posted

  • ivywong by ivywong scientist, admin

    Oops, thanks @JeanTate for pitching in. I forgot to click the 'submit' button from yesterday so here it is: The UvS just stands for a UV source. Given the separation of the GALEX UvS from the SDSS position of the blue object is <1 arcsec, I think that the GALEX source is likely to be the galaxy/QSO. Note that the position of the B3 source come from a radio survey (you can see this if you look at the Refs and Position in NED for the B3 source) so an offset of 3" might mean that there is either a high-z source or it could be emission from the QSO. Note that the B3 source is the radio source that you are seeing in the FIRST images.

    Posted

  • vrooje by vrooje admin, scientist

    This is just a test post, which I will remove shortly. Ivy's post above has gotten cut off and we're trying to figure out why.

    The quick brown fox jumped over the lazy dog. The quick brown fox jumped over the lazy dog. The quick brown fox jumped over the lazy dog. The quick brown fox jumped over the lazy dog. The quick brown fox jumped over the lazy dog. The quick brown fox jumped over the lazy dog. The quick brown fox jumped over the lazy dog. The quick brown fox jumped over the lazy dog. The quick brown fox jumped over the lazy dog. The quick brown fox jumped over the lazy dog.

    Posted

  • Dolorous_Edd by Dolorous_Edd

    Maybe not the case , but this could happen when using less-than sign

    everything after it just disappear

    Posted

  • vrooje by vrooje admin, scientist in response to Dolorous Edd's comment.

    Yep, it looks like that's what this was... can be fixed by using "&lt;" instead of "<" but it's not like it gives you any indication that that's what's wrong!

    Posted

  • ivywong by ivywong scientist, admin

    Thanks heaps @vrooje (& @DolorousEdd). It's my fault, I will refrain from using symbols in future comments. In any case, here is a continuation of what got cut off above:

    less than 1 arcsec, I think that the GALEX source is likely to be the galaxy/QSO. Note that the position of the B3 source come from a radio survey (you can see this if you look at the Refs and Position in NED for the B3 source) so an offset of 3 arcsec might mean that there is either a high-z source or it could be emission from the QSO. Note that the B3 source is the radio source that you are seeing in the FIRST images.

    Posted