Subj : Daily APOD Report To : All From : Ben Ritchey Date : Mon Jan 28 2019 08:25:19 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 January 28 [2] The Long Gas Tail of Spiral Galaxy D100 Image Credit & Copyright: NASA [3] , ESA [4] , Hubble [5] , Subaru Telescope [6] , W. Cramer [7] (Yale [8] ) et al. [9] , M. Yagi [10] , J. DePasquale [11] Explanation: Why is there long red streak attached to this galaxy? The streak is made mostly of glowing hydrogen [12] that has been systematically stripped away as the galaxy moved through the ambient hot gas in a cluster of galaxies. Specifically, the galaxy is spiral galaxy [13] D100, and cluster is the Coma Cluster of galaxies [14] . The red path connects to the center of D100 because the outer gas, gravitationally held less strongly, has already been stripped away [15] by ram pressure [16] . The extended gas tail is about 200,000 light-years [17] long, contains about 400,000 times the mass of our Sun [18] , and stars are forming within it. Galaxy D99, visible to D100's lower left, appears red because it glows primarily from the light of old red stars [19] -- young blue stars can no longer form because D99 has been stripped [20] of its star-forming gas. The featured false-color picture is a digitally enhanced composite of images from Earth-orbiting Hubble [21] and the ground-based Subaru [22] telescope. Studying remarkable systems [23] like this bolsters our understanding of how galaxies evolve in clusters. Tomorrow's picture: distant thing ------------------------------------------------------------------------------- < [24] | Archive [25] | Submissions [26] | Index [27] | Search [28] | Calendar [29] | RSS [30] | Education [31] | About APOD [32] | Discuss [33] | > [34] ------------------------------------------------------------------------------- Authors & editors: Robert Nemiroff [35] (MTU [36] ) & Jerry Bonnell [37] (UMCP [38] ) NASA Official: Phillip Newman Specific rights apply [39] . NASA Web Privacy Policy and Important Notices [40] A service of: ASD [41] at NASA [42] / GSFC [43] & Michigan Tech. U. [44] ---------- Site notes: [1] archivepix.html [2] image/1901/D100gas_HubbleSubaru_1448.jpg [3] https://www.nasa.gov/ [4] https://www.esa.int/ [5] https://www.nasa.gov/content/the-hubble-story [6] https://subarutelescope.org/ [7] https://astronomy.yale.edu/people/william-cramer [8] https://astronomy.yale.edu/ [9] http://adsabs.harvard.edu/abs/2018arXiv181104916C [10] https://www.iau.org/administration/membership/individual/8902/ [11] http://jdepasquale.com/ [12] https://en.wikipedia.org/wiki/H-alpha [13] http://cas.sdss.org/dr6/en/proj/basic/galaxies/spirals.asp [14] ap180326.html [15] https://youtu.be/KGpMC28W42Y [16] https://en.wikipedia.org/wiki/Ram_pressure [17] https://spaceplace.nasa.gov/light-year/en/ [18] https://solarsystem.nasa.gov/solar-system/sun/in-depth/ [19] ap060704.html [20] ap180825.html [21] http://www.stsci.edu/hst/HST_overview [22] https://subarutelescope.org/Introduction/index.html [23] http://adsabs.harvard.edu/abs/2018arXiv181104916C [24] ap190127.html [25] archivepix.html [26] lib/apsubmit2015.html [27] lib/aptree.html [28] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search [29] calendar/allyears.html [30] /apod.rss [31] lib/edlinks.html [32] lib/about_apod.html [33] http://asterisk.apod.com/discuss_apod.php?date=190128 [34] ap190129.html [35] http://www.phy.mtu.edu/faculty/Nemiroff.html [36] http://www.phy.mtu.edu/ [37] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html [38] http://www.astro.umd.edu/ [39] lib/about_apod.html#srapply [40] https://www.nasa.gov/about/highlights/HP_Privacy.html [41] https://astrophysics.gsfc.nasa.gov/ [42] https://www.nasa.gov/ [43] https://www.nasa.gov/centers/goddard/ [44] http://www.mtu.edu/ --- Mystic BBS v1.12 A42 (Windows/32) * Origin: FIDONet - The Positronium Repository (1:393/68) .