Astronomy Picture of the Day

   [1]Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                               2021 August 23
     [2]The picture shows galaxy cluster Abell 3827 from Hubble. Cluster
   galaxies are seen merging and a complex image of a background galaxy is
     seen where the cluster acts as a gravitational lens. Please see the
                 explanation for more detailed information.

               Abell 3827: Cannibal Cluster Gravitational Lens
           Image Credit: [3]ESA/[4]Hubble & [5]NASA, [6]R. Massey

   Explanation: Is that one galaxy or three? Toward the right of the
   [7]featured Hubble image of the massive galaxy cluster Abell 3827 is
   what appears to be a most unusual galaxy -- curved and with three
   centers. A [8]detailed analysis, however, finds that these are three
   images of the same background galaxy -- and that there are at least
   four more images. Light we see from the single background blue galaxy
   takes [9]multiple paths through the complex gravity of the cluster,
   just like a single distant light can take multiple paths [10]through
   the stem of a wine glass. [11]Studying how clusters like Abell 3827 and
   their component [12]galaxies deflect distant light gives
   [13]information about how mass and [14]dark matter are distributed.
   Abell 3827 is so distant, having a redshift of 0.1, that the light we
   see from it [15]left about 1.3 billion years ago -- before
   [16]dinosaurs roamed the Earth. Therefore, [17]the cluster's central
   galaxies have now surely all coalesced -- in a feast of [18]galactic
   cannibalism -- into [19]one huge galaxy near the cluster's center.

                Tomorrow's picture: planet-forming space disk
     __________________________________________________________________

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    Authors & editors: [31]Robert Nemiroff ([32]MTU) & [33]Jerry Bonnell
                                 ([34]UMCP)
          NASA Official: Phillip Newman [35]Specific rights apply.
              [36]NASA Web Privacy Policy and Important Notices
                A service of: [37]ASD at [38]NASA / [39]GSFC
                           & [40]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2108/Abell3827Lens_Hubble_960.jpg
   3. https://www.esa.int/
   4. https://esahubble.org/
   5. https://www.nasa.gov/
   6. http://www.astro.dur.ac.uk/~rjm/cv.php
   7. https://esahubble.org/images/potw2118a/
   8. https://academic.oup.com/mnras/article/477/1/669/4974390
   9. https://en.wikipedia.org/wiki/Gravitational_lens
  10. https://youtu.be/vLp6CwElGP4
  11. https://i.pinimg.com/originals/94/6e/ff/946eff7741c6af1436dfe4975d31d95c.jpg
  12. https://youtu.be/VeAVmp9MLH4
  13. https://aasnova.org/2020/07/21/the-fault-in-our-unaligned-stars/
  14. https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy
  15. http://www.astro.ucla.edu/~wright/CosmoCalc.html
  16. https://youtu.be/3_UJOdFx89I
  17. https://apod.nasa.gov/apod/ap980831.html
  18. https://www.universetoday.com/89086/galactic-cannibalism/
  19. https://en.wikipedia.org/wiki/ESO_146-5
  20. https://apod.nasa.gov/apod/ap210822.html
  21. https://apod.nasa.gov/apod/archivepix.html
  22. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  23. https://apod.nasa.gov/apod/lib/aptree.html
  24. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  25. https://apod.nasa.gov/apod/calendar/allyears.html
  26. https://apod.nasa.gov/apod.rss
  27. https://apod.nasa.gov/apod/lib/edlinks.html
  28. https://apod.nasa.gov/apod/lib/about_apod.html
  29. http://asterisk.apod.com/discuss_apod.php?date=210823
  30. https://apod.nasa.gov/apod/ap210824.html
  31. http://www.phy.mtu.edu/faculty/Nemiroff.html
  32. http://www.phy.mtu.edu/
  33. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  34. http://www.astro.umd.edu/
  35. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  36. https://www.nasa.gov/about/highlights/HP_Privacy.html
  37. https://astrophysics.gsfc.nasa.gov/
  38. https://www.nasa.gov/
  39. https://www.nasa.gov/centers/goddard/
  40. http://www.mtu.edu/