definite overlap, by a billion light years... your challenge

• by Budgieye moderator

  Yes, agree, this is an overlap. The galaxy behind is considerable more red than the target galaxy.

  Just by looking, I estimate that the z of the target galaxy is about 0.2 and the further galaxy is 0.4

  and the distance between the two is about two billion light years. In comparison, the Andromeda Galaxy is about 0.002 billion light years away.

  0.1 to 0.2 is approximately a billion light-years, same with 0.2 to 0.3 etc.

  Estimating distance by colour see PAGE 2 Galaxy Redshift Chart http://talk.galaxyzoo.org/#/boards/BGZ0000007/discussions/DGZ0000ulp?page=2

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  I looked up the numbers anyway,

  Photoz = 0.136

  objID 1237679009315357147 http://skyserver.sdss.org/dr8/en/tools/explore/obj.asp?id=1237679009315357147
  Photoz 0.136261 zErr 0.010019

  Photoz = 0.354

  objID 1237679009315357148 http://skyserver.sdss.org/dr8/en/tools/explore/obj.asp?id=1237679009315357148
  Photoz 0.354596zErr 0.024142

  see 7.3 Measure distance, size http://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0000wrb?page=7&comment_id=53d8bb6c0d43f776b00010af

  How far apart are the two galaxies?You can do it for yourself\

  http://www.wolframalpha.com/input/?i=cosmological+redshift , then click on Formula , and input the photoz

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  target galaxy is z = 0.136 is 1.82 billion light-years away

  red overlapped galaxy is 0.354 is 4.53 billion light-years away

  The two galaxies are 2.71 billion light-years apart. Oh well, I was sort of close.

  More fun with numbers! 😃 7.3 Measure distance, size http://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0000wrb?page=7&comment_id=53d8bb6c0d43f776b00010af

  Posted March 14, 2015 1:37 AM