Subj : Daily APOD Report To : All From : Ben Ritchey Date : Mon Sep 17 2018 13:14:47 Astronomy Picture of the Day Astronomy Picture of the Day Discover the cosmos! [1] Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2018 September 17 [2] Cosmic Collision Forges Galactic Ring Image Credit: X-ray: Chandra [3] (NASA [4] , CXC [5] , INAF [6] , A. Wolter et al. [7] ); Optical: Hubble [8] (NASA [9] , STScI [10] ) Explanation: How could a galaxy become shaped like a ring? The rim of the blue galaxy pictured [11] on the right is an immense ring-like structure 150,000 light years [12] in diameter composed of newly formed, extremely bright, massive stars. That galaxy, AM 0644-741 [13] , is known as a ring galaxy [14] and was caused by an immense galaxy collision. When galaxies collide [15] , they pass through each other -- their individual stars rarely come into contact. The ring [16] -like shape is the result of the gravitational disruption [17] caused by an entire small intruder [18] galaxy passing through a large one. When this happens, interstellar gas and dust [19] become condensed, causing a wave of star formation [20] to move out from the impact point like a ripple across the surface of a pond. The likely intruder galaxy is on the left of this combined image from Hubble [21] (visible [22] ) and Chandra [23] (X-ray [24] ) space telescopes. X-ray light is shown in pink and depicts places [25] where energetic black holes or neutron stars [26] , likely formed shortly after the galaxy collision [27] , reside. Open Science: Browse 1,800+ codes in the Astrophysics Source Code Library [28] Tomorrow's picture: a rose for a swan ------------------------------------------------------------------------------- < [29] | Archive [30] | Submissions [31] | Index [32] | Search [33] | Calendar [34] | RSS [35] | Education [36] | About APOD [37] | Discuss [38] | > [39] ------------------------------------------------------------------------------- Authors & editors: Robert Nemiroff [40] (MTU [41] ) & Jerry Bonnell [42] (UMCP [43] ) NASA Official: Phillip Newman Specific rights apply [44] . NASA Web Privacy Policy and Important Notices [45] A service of: ASD [46] at NASA [47] / GSFC [48] & Michigan Tech. U. [49] ---------- Site notes: [1] archivepix.html [2] image/1809/Ring0644_HubbleChandra_3348.jpg [3] http://chandra.harvard.edu/index.html [4] https://www.nasa.gov/ [5] http://chandra.harvard.edu/about/ [6] http://www.media.inaf.it/tag/chandra/ [7] https://arxiv.org/abs/1806.02746 [8] https://www.nasa.gov/mission_pages/hubble/story/index.html [9] https://www.nasa.gov/ [10] http://www.stsci.edu/ [11] http://chandra.si.edu/photo/2018/ring/ [12] http://chandra.harvard.edu/photo/cosmic_distance.html [13] http://adsabs.harvard.edu/abs/1997ApJ...474..686H [14] ap010612.html [15] ap150201.html [16] http://en.wikipedia.org/wiki/Engagement_ring [17] http://en.wikipedia.org/wiki/Tidal_force [18] https://s-media-cache-ak0.pinimg.com/736x/5b/60/1e/ 5b601e8413f01f169a27dffd3a1e1601.jpg [19] ap030706.html [20] http://astronomy.swin.edu.au/cosmos/D/density+wave+model [21] http://www.stsci.edu/hst/HST_overview/ [22] https://science.nasa.gov/ems/09_visiblelight [23] https://www.nasa.gov/mission_pages/chandra/main/index.html [24] https://science.nasa.gov/ems/11_xrays [25] https://www.youtube.com/watch?v=FgbmB_yLbZ0 [26] https://apod.nasa.gov/htmltest/rjn_bht.html [27] ap130514.html [28] http://ascl.net/code/all [29] ap180916.html [30] archivepix.html [31] lib/apsubmit2015.html [32] lib/aptree.html [33] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search [34] calendar/allyears.html [35] /apod.rss [36] lib/edlinks.html [37] lib/about_apod.html [38] http://asterisk.apod.com/discuss_apod.php?date=180917 [39] ap180918.html [40] http://www.phy.mtu.edu/faculty/Nemiroff.html [41] http://www.phy.mtu.edu/ [42] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html [43] http://www.astro.umd.edu/ [44] lib/about_apod.html#srapply [45] https://www.nasa.gov/about/highlights/HP_Privacy.html [46] https://astrophysics.gsfc.nasa.gov/ [47] https://www.nasa.gov/ [48] https://www.nasa.gov/centers/goddard/ [49] http://www.mtu.edu/ --- Mystic BBS v1.12 A39 (Windows/32) * Origin: FIDONet - The Positronium Repository (1:393/68) .