Galaxy Zoo Talk

Blue/Purple object in SDSS images

  • planetaryscience by planetaryscience

    While looking through SDSS images for asteroids, I happened upon this blueish-purple object. Most of the white dwarfs I've encountered have been blue in color, and most planetary nebulae I've seen have been larger than this. Is this a blue pea? Perhaps a distant planetary nebula? It has minor ultraviolet emission, and negligible X-ray emission (to what I can tell).

    ID: 1237678832149528761

    Image:

    enter image description here
    RA/DEC : 01 24 06.59 +08 38 06.9

    Posted

  • Dolorous_Edd by Dolorous_Edd

    Hmmm UKIRT image

    SDSS J012406.58+083806.9 supposed to be in the center, but it is not

    ph_z = 0.187

    enter image description here

    Posted

  • planetaryscience by planetaryscience

    in WISE images there's a definite increase in brightness towards far-infrared bands (peaking at WISE 3). Most white dwarfs (as far as I know) have a decrease in brightness as one goes further into infrared. Based on this, I think the object is probably extragalactic in nature, assuming that no such object exists in the Milky Way.

    Posted

  • Dolorous_Edd by Dolorous_Edd

    Sanity check

    Lets check that this is not an artifact

    DSS2 Blue

    enter image description here

    Object is clearly visible in DSS Blue, not so visible in DSS Red and completly invisible in IR ( consistent with UKIRT UKIDSS image )

    Object is not ALLWISE nor WISE source

    Posted

  • planetaryscience by planetaryscience

    here's the location in WISE Images. It's dim enough that it's not obvious, but it's still present to band 4.

    Posted

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

    I saw it, but it seems to absent from ALLWISE and WISE catalogs

    Perhaps this could be "purple pea galaxy" ? , not a star

    May wanna check 2014A&A...568A.126B for photo z ( aside from SDSS DR12 ph_z = 0.187)

    Posted

  • Budgieye by Budgieye moderator

    I think it looks like a blue star or a white dwarf. Purple or blue peas will look fuzzier, and purple peas have some red in them.

    Redshift Chart http://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0000ulp?page=2

    image of white dwarf here.

    4.5 white dwarf stars, neutron stars http://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0000wrb?page=4&comment_id=53d8b9d1db90c76202001111

    Posted

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

    If it is star, why it doesn't show up in UKIDSS image? and in IR generally ( it is visible even in DSS )

    +SDSS pipeline thinks it is a galaxy

    BTW ( completly unrelated ) Link to

    2014A&A...568A.126B is http://arxiv.org/abs/1407.2527

    Update

    Checked the photometric redshift from 2014A&A...568A.126B and it equals = 0.06581

    Posted

  • Dolorous_Edd by Dolorous_Edd

    Was imaged by Subaru telescope

    enter image description here

    Posted

  • Budgieye by Budgieye moderator

    Neighbourhood check, the colour balance of other objects seems OK. There is an asteroid at one oclock of the bright star, and the asteroid appears the normal three colours.

    enter image description here

    magnify, object does seem to be quite bright and small.

    enter image description here

    Posted

  • Budgieye by Budgieye moderator

    Maybe a cataclysmic star?Here is a cataclysmic variable star for comparison. Some are bluer, some are redder.

    enter image description here

    http://skyserver.sdss.org/dr12/en/tools/explore/Summary.aspx?id=1237652600099176775
    enter image description here

    http://www.galaxyzooforum.org/index.php?topic=277190.msg443191#msg443191 posted by elizabeth

    Cataclysmic variable star thread http://www.galaxyzooforum.org/index.php?topic=277190.0

    also see this binary star posted by mitch in the spectroscopic binary thread

    http://www.galaxyzooforum.org/index.php?topic=10274.msg633936#msg633936

    Posted

  • Dolorous_Edd by Dolorous_Edd

    1. SDSS J205914.87-061220.4 is clearly visible in Galex near UV and Far UV

    SDSS J012406.58+083806.9 is only slightly visible in Galex near UV

    I mean, if it was a WD / cataclysmic star , it should be a notable source of UV .. it is not

    1. SDSS J205914.87-061220.4 is clearly visible in DSS 2 IR

    SDSS J012406.58+083806.9 is not visible in DSS 2 IR

    1. SDSS J012406.58+083806.9 seems to be slightly visible in WISE 3 & 4 bands and not so in band 1&2

    Edit*

    Listed in USNO B1 catalog as

    USNO-B1.0 0986-0012232

    Posted