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.

                                2022 March 30

         IFRAME: [2]https://www.youtube.com/embed/m8qvOpcDt1o?rel=0

                        Animation: Odd Radio Circles
       Credits: Illustration: [3]Sam Moorfield; Data: [4]CSIRO, [5]HST
                         ([6]HUDF), [7]ESA, [8]NASA;
    Image: [9]J. English ([10]U. Manitoba), [11]EMU, [12]MeerKAT, [13]DES
                    ([14]CTIO); Text: [15]Jayanne English

   Explanation: What do you call a cosmic puzzle that no one expected to
   see? In this case, [16]Odd Radio Circles, aka ORCs. ORC-1 typifies the
   enigmatic five objects, only visible at [17]radio frequencies, that
   were [18]serendipitously discovered in 2019 using the new
   [19]Australian [20]SKA Pathfinder radio array. The final image in the
   featured video uses 2021 data from the [21]South African [22]MeerKAT
   array to reveal more detail. The radio data, assigned turquoise colors,
   are combined with a [23]Dark Energy Survey optical/[24]IR map. The
   animated artist’s illustration explores just one idea about the
   [25]ORCs’ origins. If two supermassive [26]black holes merge in the
   center of a galaxy, the associated [27]shockwaves could generate rings
   of radio radiation. [28]These grow to fill the video frame. The video
   [29]zooms out so the expansion the [30]ORC can be tracked until it is
   about a million [31]light-years across. Fortunately, the up-coming
   [32]Square Kilometer Array can help test this and other promising
   scenarios.

                       Tomorrow's picture: open space
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    Authors & editors: [44]Robert Nemiroff ([45]MTU) & [46]Jerry Bonnell
                                 ([47]UMCP)
          NASA Official: Phillip Newman [48]Specific rights apply.
              [49]NASA Web Privacy Policy and Important Notices
                A service of: [50]ASD at [51]NASA / [52]GSFC
                           & [53]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://www.youtube.com/embed/m8qvOpcDt1o?rel=0
   3. https://sammoorfield.com/
   4. https://www.csiro.au/
   5. https://hubblesite.org/
   6. https://esahubble.org/images/heic0611b/
   7. https://www.esa.int/
   8. https://www.nasa.gov/
   9. https://jayannecosmoscanvas.wordpress.com/
  10. https://sci.umanitoba.ca/physics-astronomy/
  11. http://emu-survey.org/
  12. https://www.sarao.ac.za/science/meerkat/about-meerkat/
  13. https://www.darkenergysurvey.org/collaboration-and-sponsors/
  14. https://noirlab.edu/public/programs/ctio/
  15. http://www2.physics.umanitoba.ca/u/english/
  16. https://en.wikipedia.org/wiki/Odd_radio_circle
  17. https://science.nasa.gov/ems/05_radiowaves
  18. https://ui.adsabs.harvard.edu/abs/2021PASA...38....3N/abstract
  19. https://en.wikipedia.org/wiki/Australia
  20. https://en.wikipedia.org/wiki/Australian_Square_Kilometre_Array_Pathfinder
  21. https://en.wikipedia.org/wiki/South_Africa
  22. https://www.sarao.ac.za/science/meerkat/
  23. https://www.darkenergysurvey.org/the-des-project/overview/
  24. https://science.nasa.gov/ems/07_infraredwaves
  25. https://www.syfy.com/syfy-wire/not-aliens-but-orcs-what-are-these-mysterious-giant-radio-rings-in-the-sky
  26. https://apod.nasa.gov/apod/ap190414.html
  27. https://apod.nasa.gov/apod/ap110925.html
  28. https://theconversation.com/odd-radio-circles-that-baffled-astronomers-are-likely-explosions-from-distant-galaxies-178290
  29. https://www.rover.com/blog/wp-content/uploads/2019/07/51nbKlz5ssL.jpg
  30. https://youtu.be/fTT3VE61jN8
  31. https://spaceplace.nasa.gov/light-year/en/
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  42. http://asterisk.apod.com/discuss_apod.php?date=220330
  43. https://apod.nasa.gov/apod/ap220331.html
  44. http://www.phy.mtu.edu/faculty/Nemiroff.html
  45. http://www.phy.mtu.edu/
  46. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  47. http://www.astro.umd.edu/
  48. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  49. https://www.nasa.gov/about/highlights/HP_Privacy.html
  50. https://astrophysics.gsfc.nasa.gov/
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