                        Astronomy Picture of the Day

    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.

                                2023 July 15

                           Webb's First Deep Field
                 Image Credit: NASA, ESA, CSA, STScI, NIRCam

   Explanation: This stunning infrared image was released one year ago as
   the James Webb Space Telescope began its exploration of the cosmos. The
   view of the early Universe toward the southern constellation Volans was
   achieved in 12.5 hours of exposure with Webb's NIRCam instrument. Of
   course the stars with six spikes are well within our own Milky Way.
   Their diffraction pattern is characteristic of Webb's 18 hexagonal
   mirror segments operating together as a single 6.5 meter diameter
   primary mirror. The thousands of galaxies flooding the field of view
   are members of the distant galaxy cluster SMACS0723-73, some 4.6
   billion light-years away. Luminous arcs that seem to infest the deep
   field are even more distant galaxies though. Their images are distorted
   and magnified by the dark matter dominated mass of the galaxy cluster,
   an effect known as gravitational lensing. Analyzing light from two
   separate arcs below the bright spiky star, Webb's NIRISS instrument
   indicates the arcs are both images of the same background galaxy. And
   that galaxy's light took about 9.5 billion years to reach the James
   Webb Space Telescope.

                   Tomorrow's picture: view with a thrill
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
                NASA Web Privacy Policy and Important Notices
                      A service of: ASD at NASA / GSFC
                           NASA Science Activation
                             & Michigan Tech. U.

