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The Virgo Cluster of Galaxie
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| Title |
The Virgo Cluster of Galaxies |
| Explanation |
Pictured are several galaxies of the Virgo Cluster, the closest cluster of galaxies [ http://www.astr.ua.edu/white/mug/cluster/clusters.html ] to our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap990224.html ]. The Virgo Cluster [ http://www.seds.org/messier/more/virgo.html ] spans more than 5 degrees on the sky - about 10 times the angle made by a full Moon [ http://antwrp.gsfc.nasa.gov/apod/ap991108.html ]. It contains over 100 galaxies of many types - including spirals [ http://antwrp.gsfc.nasa.gov/apod/spiral_galaxies.html ], ellipticals [ http://antwrp.gsfc.nasa.gov/apod/elliptical_galaxies.html ], and irregular [ http://www.seds.org/messier/irre.html ] galaxies. The Virgo Cluster [ http://www.astr.ua.edu/white/mug/cluster/virgo.html ] is so massive that it is noticeably pulling our Galaxy toward it. The cluster contains not only galaxies filled with stars but also gas so hot [ http://antwrp.gsfc.nasa.gov/apod/ap960419.html ] it glows in X-rays [ http://www.optonline.com/comptons/ceo/05250_A.html ]. Motions of galaxies in and around clusters indicate that they contain more dark matter [ http://cfpa.berkeley.edu/darkmat/dm.html ] than any visible matter we can see. Notable bright galaxies in the Virgo Cluster include bright Messier objects [ http://antwrp.gsfc.nasa.gov/apod/messier.html ] such as M61 [ http://antwrp.gsfc.nasa.gov/apod/ap980922.html ], M87 [ http://antwrp.gsfc.nasa.gov/apod/ap950913.html ], M90 [ http://antwrp.gsfc.nasa.gov/apod/ap960316.html ], and M100 [ http://antwrp.gsfc.nasa.gov/apod/ap980606.html ]. |
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M61: Virgo Spiral Galaxy
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M61: Virgo Spiral Galaxy |
| Explanation |
M61 is a barred spiral galaxy located in the nearby Virgo Cluster of Galaxies [ http://www.seds.org/messier/more/virgo_gal.html ]. Visible in M61 [ http://www.seds.org/messier/m/m061.html ] are a host of features common to spiral galaxies [ http://www.astro.princeton.edu/~frei/catalog.htm ]: bright spiral arms [ http://www.astronomy.ohio-state.edu/~pogge/Ast162/Wi97/Unit4/spirals.html ], a central bar [ http://antwrp.gsfc.nasa.gov/apod/ap970519.html ], dust lanes [ http://antwrp.gsfc.nasa.gov/apod/ap980116.html ], and bright knots of stars. M61 [ http://crux.astr.ua.edu/gifimages/m61r.html ], also known as NGC 4303 [ http://www.astro.princeton.edu/~frei/Gcat_htm/Sub_sel/gal_4303.htm ], in similar to our own Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap971229.html ]. M61 was discovered by telescope in 1779 twice on the same day, but one observer initially mistook the galaxy for a comet. Light from M61 [ http://siggy.iusb.edu/netah/messier/mess-pict/pages/m061.html ] takes about 60 million years to reach us. Recent observations of M61 have detected unpredicted high velocity gas [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1996ApJ...472L..77B&db_key=AST&nosetcookie=1&high=33613e8e5802351 ] moving in its halo. |
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