Why is the background in infrared darker than other images?

• by Gust644

  Would be older galaxies?

  Posted July 21, 2017 2:46 AM

• by JeanTate in response to Gust644's comment.

  Welcome to Radio Galaxy Zoo, Gust644! 😃

  I too have often wondered why some of the fields have much darker IR backgrounds than most. A hand-waving technical answer might be something like: the color scale of the background (WISE, IR) jpgs is determined by an algorithm which is designed to give a dynamic range of X; sometimes the median pixel value gets set much closer to zero (black) than usual (typically ~100). However, I'd be guessing, and in any case I think such an answer isn't helpful.

  Would be older galaxies?

  No. The objects in this field (image) are not particularly special, as this SDSS version of the image shows:

  

  Hope this helps, and happy hunting! 😃

  Posted July 24, 2017 3:29 PM

• by Gust644

  thak you, your coment was very useful. 😃

  Posted September 6, 2017 2:21 AM