﻿ 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 __________________________________________________________________ [33]< | [34]Archive | [35]Submissions | [36]Index | [37]Search | [38]Calendar | [39]RSS | [40]Education | [41]About APOD | [42]Discuss | [43]> __________________________________________________________________ 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/ 32. https://www.skatelescope.org/history-of-the-skaproject/ 33. https://apod.nasa.gov/apod/ap220329.html 34. https://apod.nasa.gov/apod/archivepix.html 35. https://apod.nasa.gov/apod/lib/apsubmit2015.html 36. https://apod.nasa.gov/apod/lib/aptree.html 37. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 38. https://apod.nasa.gov/apod/calendar/allyears.html 39. https://apod.nasa.gov/apod.rss 40. https://apod.nasa.gov/apod/lib/edlinks.html 41. https://apod.nasa.gov/apod/lib/about_apod.html 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/ 51. https://www.nasa.gov/ 52. https://www.nasa.gov/centers/goddard/ 53. http://www.mtu.edu/