Radio Galaxy Zoo Talk

Image ARG0002vkz

  • leonie_van_vliet by leonie_van_vliet

    The last few days I've encountered objects that look like asteroids in images as my comment on ARG0002i7r:
    "Thought it to be an asteroid, zoomed in & took screenshot due to lovely colors & often seen in GZ"
    Would that actually be possible here in RGZ?
    Just wondering!

    ~Leonie

    Posted

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

    There's no doubt that ARG0002i7r does contain an asteroid, in the SDSS view. Asteroids, in SDSS, show up as three point sources (sometimes streaks), a blue, red, and green (or the other way round); this is due to how the SDSS camera works (or worked, it's now in a museum somewhere): it scans the sky, with a point on the sky passing over the five filters successively (the u' band is not displayed, nor the z' band; the g' band is mapped to blue, r' to green, and i' to red). If an object is moving, it will hit the camera in five different positions, of which we see just three. If the movement is slow enough, the red and green overlap somewhat, producing a yellow spot, as in this field.

    Here it is:

    enter image description here

    Would that actually be possible here in RGZ?

    Not only possible, but to be expected! You've probably classified RGZ/ARG fields with asteroids in the SDSS view before, but may not have noticed them (faint asteroids aren't easy to see, for example, and slow-moving ones may look like an oddly-colored, elongated, blob).

    Hope this helps, and happy hunting! 😃

    Posted

  • leonie_van_vliet by leonie_van_vliet

    Thanks Jean,
    As always there to answer a question that maybe obvious, although sometimes classified as STAR in SDSS which I thought to be odd. Know about asteroids enough to recognize them as such but became doubtful!

    Cheers!
    Leonie 

    Posted