Detail View: NASA Astronomy Picture of the Day Collection: A Quintet of Galaxies

Title: 
A Quintet of Galaxies
Explanation: 
Five closely grouped galaxies are visible in this image made using the Kitt Peak National Observatory [ http://www.noao.edu/kpno/kpno.html ] 2.1 meter telescope. The grouping is commonly known as Stephan's Quintet [ http://crux.astr.ua.edu/gifimages/stephan.html ]. Four of the galaxies show essentially the same redshift [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#redshift ] suggesting that they are at the same distance from us. The large bluish spiral below and left of center actually has a smaller redshift than the others, indicating it is much closer. It is probably a foreground object which happens to lie along the line of sight to the more distant galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap950907.html ]. Of the four distant galaxies, three seem to be colliding, showing serious distortions due to gravitational tidal forces. The fourth is a normal appearing elliptical galaxy (at the lower right edge of the field). Recent results [ http://www.stsci.edu/pubinfo/PR/94/52.html ] suggest that collisions play an important role in the life cycles of galaxies.
Credit and Copyright: 
W.C. Keel [ http://crux.astr.ua.edu/keel/billkeel.html ] (University of Alabama) [ http://crux.astr.ua.edu/AstroHome.html ] and R.E. White, III
facet_where: 
Alabama
facet_what: 
Crux
original url: 
http://antwrp.gsfc.nasa.gov/apod/ap951115.html
UID: 
SPD-APOD-ap951115