UDF 423 is the spiral galaxy in the lower right quadrant of the Hubble Ultra Deep Field.

UDF 423 is the Hubble Ultra Deep Field (UDF) identifier for a distant spiral galaxy. With an apparent magnitude of 20,[1] UDF 423 is one of the brightest galaxies in the HUDF and also has one of the largest apparent sizes in the HUDF.[1]

Distance measurements

The "distance" of a far away galaxy depends on how it is measured. With a redshift of 1,[2] light from this galaxy is estimated to have taken around 7.7 billion years to reach Earth.[3] However, since this galaxy is receding from Earth, the present comoving distance is estimated to be around 10 billion light-years away.[3] In context, Hubble is observing this galaxy as it appeared when the Universe was around 4.9 billion years old.[3]

See also

References

  1. ^ a b c d e f "UDF 423". Wikisky. Retrieved 2010-11-03.
  2. ^ a b Sangeeta Malhotra. "As far as the Hubble can see" (PDF). Arizona State University. Retrieved 2010-10-28.
  3. ^ a b c d e Edward L. (Ned) Wright. "Cosmology Calculator I". Astronomy @ UCLA. Retrieved 2010-10-22.


Allikas: https://en.wikipedia.org/wiki/UDF_423
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