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NGC 3314: When Galaxies Over
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| Title |
NGC 3314: When Galaxies Overlap |
| Explanation |
Can this be a spiral galaxy? In fact, NGC 3314 [ http://oposite.stsci.edu/pubinfo/pr/2000/14/index.html ] consists of two large spiral galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap980314.html ] which just happen to almost exactly line-up. The foreground spiral is viewed nearly face-on, its pinwheel shape defined by young bright star clusters. But against the glow of the background galaxy, dark swirling lanes of interstellar dust [ http://antwrp.gsfc.nasa.gov/apod/ap980116.html ] are also seen [ http://antwrp.gsfc.nasa.gov/apod/ap971205.html ] to echo the face-on spiral's structure. The dust lanes [ http://antwrp.gsfc.nasa.gov/apod/ap990821.html ] are surprisingly pervasive, and this remarkable pair of [ http://www.astr.ua.edu/white/pairs/individual.html ] overlapping galaxies is one of a small number of systems in which absorption of visible light can be used to directly explore the distribution [ http://www.astr.ua.edu/white/pairs/thickthin.html ] of dust in distant spirals. NGC 3314 is [ http://heritage.stsci.edu/public/2000may11/about3314.html ] about 140 million light-years away in the southern constellation of Hydra [ http://www.astronomical.org/constellations/ hya.html ]. Just released [ http://heritage.stsci.edu/ ], this color composite was constructed from Hubble Space Telescope images made in 1999 and 2000. |
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Supernova Factory NGC 2770
| Title |
Supernova Factory NGC 2770 |
| Explanation |
The stellar explosions known as supernovae are [ http://en.wikipedia.org/wiki/Supernova] among the most powerful events [ http://antwrp.gsfc.nasa.gov/apod/ap990515.html ] in the universe. Triggered by the collapsing core of a massive star or the nuclear demise of a white dwarf, supernovae occur [ http://www.rochesterastronomy.org/SNIMAGES/ ] in average spiral galaxies only about once every century. But the remarkable spiral galaxy NGC 2770 has lately produced more than its fair share. Two still bright supernovae and the location of a third, originally spotted in 1999 but now faded from view, are indicated in this image of the edge-on spiral. All three supernovae are now thought to be of the core-collapse variety, but the most recent of the trio, SN2008D [ http://grad40.as.utexas.edu/ grblog.php?view-burst&GRB=080109A ], was first detected [ http://www.astronomerstelegram.org/?read=1353 ] by the Swift satellite [ http://swift.gsfc.nasa.gov/docs/swift/swiftsc.html ] at more extreme energies as an X-ray flash [ http://chandra.harvard.edu/press/03_releases/ press_091103.html ] (XRF) or possibly a low-energy version of a gamma-ray burst [ http://www.npr.org/templates/story/ story.php?storyId=4679036 ] on January 9th. Located a mere [ http://www.pbs.org/wgbh/nova/gamma/milkyway.html ] 90 million light-years away in the northern constellation Lynx, NGC 2770 is now the closest galaxy known to host such a powerful supernova event [ http://antwrp.gsfc.nasa.gov/apod/ap020228.html ]. |
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The Stars of NGC 1705
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The Stars of NGC 1705 |
| Explanation |
Some 2,000 light-years across, NGC 1705 is small as galaxies go, similar to our Milky Way's own satellite galaxies, the Magellanic Clouds [ http://antwrp.gsfc.nasa.gov/apod/ap980203.html ]. At a much larger distance of 17 million light-years, the stars of NGC 1705 [ http://hubblesite.org/newscenter/archive/2003/07/image/a ] are still easily resolved in this beautiful image [ http://heritage.stsci.edu/2003/07/big.html ] constructed from data taken in 1999 and 2000 with the Hubble Space Telescope. Most of the younger, hot, blue [ http://antwrp.gsfc.nasa.gov/apod/ap961202.html ] stars in the galaxy are seen to be concentrated in a large central star cluster with the older, cooler [ http://antwrp.gsfc.nasa.gov/apod/ap010223.html ], red stars more evenly distributed. Possibly 13 billion years old, NGC 1705 [ http://hubblesite.org/newscenter/archive/2003/07/ fastfacts ] could well have been forming stars through out its lifetime while light from its most recent burst of star formation reached Earth only 30 million years ago. This gradually evolving dwarf irregular galaxy lacks organized [ http://hubblesite.org/newscenter/archive/1996/29/ astrofile#2 ] structures like spiral arms and is thought to be a nearby analog to the first galaxies [ http://www.ipac.caltech.edu/Outreach/Edu/early.html ] to form in the early Universe [ http://antwrp.gsfc.nasa.gov/apod/ap030212.html ]. |
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NGC 3314: When Galaxies Over
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| Title |
NGC 3314: When Galaxies Overlap |
| Explanation |
NGC 3314 [ http://hubblesite.org/newscenter/newsdesk/archive/ releases/2000/14/ ] consists of two large spiral galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap980314.html ] which just happen to almost exactly line-up. The foreground spiral is viewed nearly face-on [ http://antwrp.gsfc.nasa.gov/apod/ap040410.html ], its pinwheel shape defined by young bright star clusters. But against the glow of the background galaxy, dark swirling lanes of interstellar dust [ http://antwrp.gsfc.nasa.gov/apod/ap030706.html ] are also seen to echo the face-on spiral's structure. The dust lanes [ http://antwrp.gsfc.nasa.gov/apod/ap990821.html ] are surprisingly pervasive, and this remarkable pair of [ http://www.astr.ua.edu/white/pairs/individual.html ] overlapping galaxies is one of a small number of systems in which absorption of visible light can be used to directly explore the distribution [ http://www.astr.ua.edu/white/pairs/thickthin.html ] of dust in distant spirals. NGC 3314 is [ http://hubblesite.org/newscenter/newsdesk/archive/ releases/2000/14/fastfacts/ ] about 140 million light-years away in the multi-headed constellation Hydra [ http://www.hawastsoc.org/deepsky/hya/index.html ]. This color composite was constructed from Hubble Space Telescope images made in 1999 and 2000. |
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