Radio Galaxy Zoo Talk

Only artefacts allowed

  • sisifolibre by sisifolibre

    This post is a continuation of this. Sorry for my english and I hope you comment any error or idea that the text sugest you. Edit: Now all the links works

    Here are some collections I have done using the "search" tool whith words "artefact", "artifact", "artefacts" and "artifacts", and using the collection of @antikodon (here). Except in the 2 last collections all are "arte(i)fact(s)" in radio image. This post is essentially about radio artefacts, but I thought that could be appropriate classify other uses of the "#arte(i)fact(s)" tag, because this I did the 6º and 7º collections.

    The ARG subjects are in the collection 1 and at least in one of the other that describe it. Some subjects are in various collections for example this that is a "scratch" caused by a near bright source and is in the total collection (1), the collection about nearby emissions (2), and the scratch collection (4).

    -1 Total collection: All the subjects that have been tagged about radio artefacts:
    http://radiotalk.galaxyzoo.org/#/collections/CRGS00017a.

    -2 Collection about objects that seem artefacts caused by strong nearby emission. I think that these subjects don't have true radio sources in his fields:
    http://radiotalk.galaxyzoo.org/#/collections/CRGS00017c.
    The most of the subjects in this collection are like this. But there are some subjects like this other
    A clue for this kind of artefacts is that they usually are in a "noise line" diagonal to the strong emision. They have a pattern. Sometimes the source of strong emision have the jets aligned with the diagonal "noise lines". Almost always the artefact is aligned whith the jets, except QSO and similar sources.

    -3 Collection about subjects that have artefacts and a real radio source in his fields: http://radiotalk.galaxyzoo.org/#/collections/CRGS00017d
    Some of this subjects have in the center the source that causes the artefacts, like here http://radiotalk.galaxyzoo.org/#/subjects/ARG0002oro But in some others the artefacts are the main objects of the field like here : http://radiotalk.galaxyzoo.org/#/subjects/ARG00035nu May be better make 2 collections of this?

    -4 Collection about objects that seems like a brand stape or scratch in the paper. I think that there aren't true radio sources in the fields of these objects, except this and this other: http://radiotalk.galaxyzoo.org/#/collections/CRGS00017e This kind of artefact may be caused by a bright source, but more far. All of them have a similar shape, seems to have some kind of repetition and pattern in FIRST. Here are some general characteristics:

    • Most of them have his brightest pixel is 3.74 mJy/beam, over the sensibility of NVSS that don't show a counterpart.

    • Regular pattern

    • Upper an lower radio contours in all lobes are straight and aligned.

    • Sice between 10'' and 35'' when look like 2 or 4 single objects, between 90'' and 110" when they look like a single stripe.

    -5 Collection about subjects which may not be artifacts because have a NVSS counterpart, a scientist have said it, or some similar evidence: http://radiotalk.galaxyzoo.org/#/collections/CRGS00017b.
    For example: http://radiotalk.galaxyzoo.org/#/subjects/ARG0001r7r

    -6. Collection about subjects that have bad IR image or IR artefact: http://radiotalk.galaxyzoo.org/#/collections/CRGS000188 There are more artefacts of this kind but they are tagged with other words or other collection like "missingIR", "unusual background", etc, and can't be confused in the caracterization of the radio artefacts.

    -7. Collection about subjects that have an artefact in SDSS: http://radiotalk.galaxyzoo.org/#/collections/CRGS000189

    I hope these collections should help to the staff with the posibility of remove subjects whose main object is an artefact.

    Posted

  • ivywong by ivywong scientist, admin

    Thanks @sisifolibre for this compilation.

    Posted