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Astronomy Picture of the Day

Posted By Editor On February 26, 2011 @ 4:43 pm In Photo Essays | Comments Disabled



Shell Galaxies in Pisces
Image Credit & Copyright [2]: Stephen Leshin [3]

Explanation: This colorful cosmic skyscape [4] features a peculiar system of galaxies cataloged as [5] Arp 227 some 100 million light-years distant. Swimming within [6] the boundaries of the constellation Pisces [7], Arp 227 consists of the two galaxies prominent [8] on the left; the curious shell galaxy NGC 474 and its blue, spiral-armed neighbor NGC 470. The faint, wide arcs or shells of NGC 474 [9] could have been formed by a gravitational encounter with neighbor NGC 470. Alternately the shells could be caused by a merger [10] with a smaller galaxy producing an effect analogous to ripples across the surface of a pond. Remarkably, the large galaxy on the right hand side of the deep image, NGC 467, appears to be surrounded by faint shells too, evidence of another interacting [11] galaxy system. Intriguing background galaxies are scattered around the field that also includes spiky [12] foreground stars. Of course, those stars lie well within our own Milky Way Galaxy [13]. The field of view spans 25 arc minutes or about 1/2 degree on the sky [14].





Visit the NASA/JPL website to view more Astronomy Pictures of the Day [15]

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URL to article: http://www.berthoudrecorder.com/astronomy-picture-of-the-day-21/

URLs in this post:

[1] Image: http://www.berthoudrecorder.com/wp-content/uploads/2011/02/Arp227friends_leshin.jpg

[2] Copyright: http://apod.nasa.gov/apod/lib/about_apod.html#srapply

[3] Stephen Leshin: http://sleshin.startlogic.com/

[4] colorful cosmic skyscape: http://sleshin.startlogic.com/stargazergallery/main.php?g2_itemId=415

[5] cataloged as: http://nedwww.ipac.caltech.edu/level5/Arp/frames.html

[6] Swimming within: http://pixinsight.com/forum/index.php?topic=2623.0

[7] constellation Pisces: http://www.pa.msu.edu/people/horvatin/Astronomy_Facts/constellation_pages/pisces.htm

[8] prominent: http://apod.nasa.gov/apod/image/1102/arp227field_leshin600.jpg

[9] shells of NGC 474: http://adsabs.harvard.edu/abs/1999IAUS..186..191T

[10] caused by a merger: http://apod.nasa.gov/apod/ap021111.html

[11] interacting: http://burro.cwru.edu/JavaLab/GalCrashWeb/

[12] spiky: http://spider.ipac.caltech.edu/staff/kaspar/obs_mishaps/images/int_reflection2.html

[13] Milky Way Galaxy: http://apod.nasa.gov/apod/ap080104.html

[14] on the sky: http://chandra.harvard.edu/photo/scale.html

[15] Astronomy Pictures of the Day: http://antwrp.gsfc.nasa.gov/apod/

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