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.

                              2019 December 16
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                  The Magnetic Fields of Spiral Galaxy M77
   Image Credit: [3]NASA, [4]SOFIA, [5]HAWC+; [6]JPL-Caltech, [7]Roma Tre.
                 U.; [8]ESA, [9]Hubble, [10]NuSTAR, [11]SDSS

   Explanation: Can magnetic fields help tell us how spiral galaxies form
   and evolve? To find out, the [12]HAWC+ instrument on NASA's airborne
   ([13]747) [14]SOFIA observatory observed nearby [15]spiral galaxy M77.
   [16]HAWC+ maps magnetism by observing [17]polarized [18]infrared light
   emitted by elongated dust grains rotating in alignment with the local
   [19]magnetic field. The HAWC+ [20]image shows that magnetic fields do
   appear to trace the spiral arms in the inner regions of [21]M77, arms
   that likely highlight density waves in the inflowing gas, dust and
   stars [22]caused by the gravity of the galaxy's oval shape. The
   [23]featured picture [24]superposes the HAWC+ image over diffuse
   [25]X-ray emission mapped by NASA's [26]NuSTAR satellite and
   [27]visible light images taken by [28]Hubble and the [29]SDSS. [30]M77
   is located about 47 million [31]light years away toward the
   constellation of the [32]Sea Monster ([33]Cetus).

                      Tomorrow's picture: red and dusty
     __________________________________________________________________

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    Authors & editors: [45]Robert Nemiroff ([46]MTU) & [47]Jerry Bonnell
                                 ([48]UMCP)
          NASA Official: Phillip Newman [49]Specific rights apply.
              [50]NASA Web Privacy Policy and Important Notices
                A service of: [51]ASD at [52]NASA / [53]GSFC
                           & [54]Michigan Tech. U.

References

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   4. https://www.nasa.gov/mission_pages/SOFIA/overview/index.html
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   6. https://www.jpl.nasa.gov/
   7. http://www.uniroma3.it/
   8. https://www.esa.int/
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  10. https://www.nustar.caltech.edu/page/about
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  13. https://www.nasa.gov/sites/default/files/thumbnails/image/sofiaoversierra.jpg
  14. https://www.sofia.usra.edu/multimedia/about-sofia
  15. https://apod.nasa.gov/apod/ap130510.html
  16. https://www.nasa.gov/ames/image-feature/one-of-a-kind-camera-added-to-sofia
  17. https://en.wikipedia.org/wiki/Polarization_(waves)
  18. https://science.nasa.gov/ems/07_infraredwaves
  19. https://www-istp.gsfc.nasa.gov/Education/Imagnet.html
  20. https://arxiv.org/abs/1907.06648
  21. https://en.wikipedia.org/wiki/Messier_77
  22. https://arxiv.org/abs/1311.2609
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  24. https://www.flickr.com/photos/dragonden/2214149648/
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  30. https://apod.nasa.gov/apod/ap061207.html
  31. https://spaceplace.nasa.gov/light-year/en/
  32. https://en.wikipedia.org/wiki/Cetus_(mythology)
  33. https://en.wikipedia.org/wiki/Cetus
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  43. http://asterisk.apod.com/discuss_apod.php?date=191216
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  45. http://www.phy.mtu.edu/faculty/Nemiroff.html
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  51. https://astrophysics.gsfc.nasa.gov/
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