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Images of M32 and Goddard Space Flight Center (GSFC)
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The Trifid Nebula: Stellar S
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| Title |
The Trifid Nebula: Stellar Sibling Rivalry |
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Dwarf Elliptical Galaxy NGC
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| Title |
Dwarf Elliptical Galaxy NGC 205 in the Local Group |
| Explanation |
Our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ] is not alone. It is part of a gathering of about 25 galaxies known as the Local Group [ http://www.seds.org/messier/more/local.html ]. Members include the Great Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap991114.html ] (M31), M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ], M33 [ http://antwrp.gsfc.nasa.gov/apod/ap980721.html ], the Large Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap000222.html ], the Small Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap000430.html ], Dwingeloo 1 [ http://antwrp.gsfc.nasa.gov/apod/ap000109.html ], several small irregular galaxies [ http://www.seds.org/messier/irre.html ], and many dwarf elliptical [ http://nedwww.ipac.caltech.edu/level5/Ferguson/frames.html ] and dwarf spheroidal galaxies [ http://www.astro.uu.se/~ns/review.html ]. Pictured [ http://www.cfht.hawaii.edu/Science/Astros/Imageofweek/ciw061299.html ] on the lower left is one of the many dwarf ellipticals [ http://www.astro.psu.edu/users/pdurrell/dE.html ]: NGC 205 [ http://www.seds.org/messier/m/m110.html ]. Like M32 [ http://www.seds.org/messier/m/m032.html ], NGC 205 [ http://nedwww.ipac.caltech.edu/level5/Hodge/Hodge5_5.html ] is a companion to the large M31, and can sometimes be seen to the south of M31 [ http://www.seds.org/messier/m/m031.html ]'s center in photographs. The above image [ http://www.cfht.hawaii.edu/Science/Astros/Imageofweek/ciw061299.html ] shows NGC 205 to be unusual [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998ApJ...499..209W ] for an elliptical galaxy [ http://antwrp.gsfc.nasa.gov/apod/elliptical_galaxies.html ] in that it contains at least two dust clouds [ http://antwrp.gsfc.nasa.gov/apod/ap990919.html ] (at 1 and 4 o'clock - they are visible but hard to spot) and signs of recent star formation [ http://antwrp.gsfc.nasa.gov/apod/stellar_nurseries.html ]. This galaxy is sometimes known as M110, although it was actually not part of Messier [ http://antwrp.gsfc.nasa.gov/apod/ap960626.html ]'s original catalog [ http://antwrp.gsfc.nasa.gov/apod/messier.html ]. |
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Moon Over Andromeda
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Moon Over Andromeda |
| Explanation |
The Great Spiral Galaxy in Andromeda [ http://antwrp.gsfc.nasa.gov/apod/ap051222.html ] (aka M31), a mere 2.5 million light-years distant [ http://arxiv.org/abs/astro-ph/0511045 ], is the closest large spiral to our own Milky Way. Andromeda is visible to the unaided eye as a small, faint, fuzzy patch, but because its surface brightness is so low, casual skygazers [ http://www.physics.ucla.edu/~huffman/m31.html ] can't appreciate the galaxy's impressive extent in planet Earth's sky. This entertaining composite image compares the angular size [ http://chandra.harvard.edu/photo/scale.html ] of the nearby galaxy to a brighter, more familiar celestial sight. In it, a deep exposure of Andromeda [ http://www.caelumobservatory.com/gallery/m31abtp.shtml ], tracing beautiful blue star clusters in spiral arms far beyond the bright yellow core, is combined with a typical view of a nearly full Moon. Shown at the same angular scale, the Moon covers about 1/2 degree on the sky, while the galaxy is clearly [ http://www.regulusastro.com/regulus/papers/ m31/ ] several times that size. The deep Andromeda exposure also includes two bright satellite galaxies, M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ] and M110 [ http://antwrp.gsfc.nasa.gov/apod/ap060908.html ] (bottom). |
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Infrared Andromeda
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Infrared Andromeda |
| Explanation |
This wide, detailed Spitzer Space Telescope view [ http://www.spitzer.caltech.edu/Media/releases/ssc2006-14/ index.shtml ] features infrared light from dust (red) and old stars (blue) in Andromeda, a massive spiral galaxy a mere 2.5 million light-years away. In fact, with over twice the diameter of our own [ http://antwrp.gsfc.nasa.gov/apod/ap050825.html ] Milky Way, Andromeda is [ http://www.seds.org/Messier/m/m031.html ] the largest nearby [ http://www.seds.org/Messier/more/ local.html ] galaxy. Andromeda's population of bright young stars define its sweeping spiral arms in visible light images [ http://antwrp.gsfc.nasa.gov/apod/ap051222.html ], but here the infrared view clearly follows the lumpy dust lanes heated by the young stars as they wind even closer to the galaxy's core [ http://antwrp.gsfc.nasa.gov/apod/ap041227.html ]. Constructed to explore [ http://nedwww.ipac.caltech.edu/level5/ANDROMEDA_Atlas/ Hodge_contents.html ] Andromeda's infrared brightness [ http://coolcosmos.ipac.caltech.edu// ] and stellar populations, the full mosaic image is composed of about 3,000 individual frames. Two smaller companion galaxies, NGC 205 [ http://antwrp.gsfc.nasa.gov/apod/ap001023.html ] (below) and M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ] (above) are also included in the combined fields. The data confirm that Andromeda (aka M31) houses around 1 trillion [ http://kokogiak.com/megapenny/thirteen.asp ] stars, compared to [ http://astronomy.swin.edu.au/~gmackie/billions.html ] 4 hundred billion [ http://kokogiak.com/megapenny/nine.asp ] for the Milky Way. |
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Local Group Galaxy NGC 205
| Title |
Local Group Galaxy NGC 205 |
| Explanation |
The Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950908.html ] is not alone. It is part of a gathering of about 25 galaxies known as the Local Group [ http://www.csc.fi/jpr/galaxy/lbang.html ]. Members include the Great Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950724.html ] (M31), M32 [ http://antwrp.gsfc.nasa.gov/apod/ap960106.html ], M33 [ http://seds.lpl.arizona.edu/messier/m/m033.html ], the Large Magellanic Clouds [ http://antwrp.gsfc.nasa.gov/apod/ap950918.html ], the Small Magellanic Clouds [ http://antwrp.gsfc.nasa.gov/apod/ap950919.html ], Dwingeloo 1 [ http://antwrp.gsfc.nasa.gov/apod/ap951017.html ], several small irregular galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap950728.html ], and many dwarf elliptical galaxies [ http://www.physics.mcmaster.ca/Grads/PRD2.html ]. Pictured is one of the many dwarf ellipticals: NGC 205. Like M32, NGC 205 is a companion to the large M31, and can sometimes be seen to the south of M31 [ http://seds.lpl.arizona.edu/messier/m/m031.html ]'s center in photographs. The above image [ http://crux.astr.ua.edu/gifimages/m110r.html ] shows this galaxy to be unusual for an elliptical galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950913.html ] in that it contains at least two dust clouds [ http://antwrp.gsfc.nasa.gov/apod/ap951107.html ] (at 7 and 11 o'clock - they are visible but hard to spot) and signs of recent star formation. This galaxy is sometimes known as M110, although it was actually not part of Messier [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#messier ]'s original catalog. |
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Dwarf Elliptical Galaxy M32
| Title |
Dwarf Elliptical Galaxy M32 |
| Explanation |
Being the largest galaxy around can sometimes make you popular. Pictured is M31's companion galaxy M32 [ http://crux.astr.ua.edu/gifimages/m32.html ]. M31 [ http://antwrp.gsfc.nasa.gov/apod/ap950724.html ], the Andromeda galaxy, is the largest galaxy in our Local Group [ http://www.csc.fi/jpr/galaxy/lbang.html ] of galaxies - even our tremendous Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap950908.html ] is smaller. Little M32 is visible in most pictures of M31 - it is the small circular spot north of M31's center. M32 is a dwarf elliptical galaxy [ http://www.physics.mcmaster.ca/Grads/PRD2.html ]. Elliptical galaxies [ http://sousun1.phys.soton.ac.uk/PH308/galaxies/ellipticals.html ] have little or no measurable gas [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#hydrogen ] or dust [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#dust ] - they are composed completely of stars [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#star ] and typically appear more red than spiral galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap951218.html ]. Elliptical galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap950913.html ] do not have disks - they generally have oblong shapes and therefore show elliptical profiles on the sky. |
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The Aquarius Dwarf
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The Aquarius Dwarf |
| Explanation |
Our Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/milky_way.html ] is not alone. It is part of a gathering of about 50 galaxies known as the Local Group [ http://www.seds.org/messier/more/local.html ]. Members include the Great Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap021021.html ] (M31), M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ], M33 [ http://antwrp.gsfc.nasa.gov/apod/ap021202.html ], the Large Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap010804.html ], the Small Magellanic Cloud [ http://antwrp.gsfc.nasa.gov/apod/ap000430.html ], Dwingeloo 1 [ http://antwrp.gsfc.nasa.gov/apod/ap000109.html ], several small irregular galaxies [ http://www.seds.org/messier/irre.html ], and many dwarf elliptical [ http://nedwww.ipac.caltech.edu/level5/Ferguson/frames.html ] and dwarf spheroidal galaxies [ http://www.astro.uu.se/~ns/review.html ]. Pictured above is the Aquarius Dwarf [ http://www.seds.org/~spider/spider/LG/aqr_dw.html ], a faint dwarf irregular galaxy over 3 million light years [ http://chandra.harvard.edu/photo/cosmic_distance.html ] away. An earlier [ http://antwrp.gsfc.nasa.gov/apod/ap970329.html ] APOD [ http://antwrp.gsfc.nasa.gov/apod/ap960204.html ] erroneously identified [ http://www.solstation.com/x-objects/sag-deg.htm ] the above image as the Sagittarius Dwarf [ http://www.seds.org/messier/more/sagdeg.html ]. |
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M32: Blue Stars in an Ellipt
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M32: Blue Stars in an Elliptical Galaxy |
| Explanation |
Elliptical galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap961106.html ] are known for their old, red stars. But is this old elliptical [ http://www.seds.org/messier/elli.html ] up to new tricks? In recent years, the centers of elliptical galaxies [ http://www.windows.umich.edu/cgi-bin/tour.cgi?link=/the_universe/Ellipticals.html ] have been found [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998AJ....116.2297P ] to emit unexpectedly high amounts of blue and ultraviolet light [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html ]. Most blue light from spiral galaxies [ http://antwrp.gsfc.nasa.gov/apod/ap990926.html ] originates from massive young hot stars [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ap981025.html ], in contrast to the red light from the old cool stars thought to compose ellipticals. In the above recently released, false-color photograph [ http://oposite.stsci.edu/pubinfo/pr/1999/40/pr-photos.html ] by the Hubble Space Telescope [ http://www.stsci.edu/hst/ ], the center of nearby dwarf elliptical M32 has actually been resolved and does indeed show thousands of bright blue stars. The answer [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999AAS...194.0713B ] is probably that these blue stars [ http://oposite.stsci.edu/pubinfo/pr/1999/40/index.html ] are also old and glow blue, reaching relatively high temperatures by the advanced process [ http://zebu.uoregon.edu/textbook/se.html ] of fusing helium [ http://antwrp.gsfc.nasa.gov/htmltest/gifcity/msblues.html ], rather than hydrogen [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#hydrogen ], in their cores. M32 [ http://antwrp.gsfc.nasa.gov/apod/ap960106.html ] appears in many pictures as the companion galaxy to the massive Andromeda Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap971101.html ] (M31). |
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Infrared Andromeda
| Title |
Infrared Andromeda |
| Explanation |
This wide, detailed Spitzer Space Telescope view [ http://www.spitzer.caltech.edu/Media/releases/ssc2006-14/ index.shtml ] features infrared light from dust (red) and old stars (blue) in Andromeda, a massive spiral galaxy a mere 2.5 million light-years away. In fact, with over twice the diameter of our own [ http://antwrp.gsfc.nasa.gov/apod/ap050825.html ] Milky Way, Andromeda is [ http://www.seds.org/Messier/m/m031.html ] the largest nearby [ http://www.seds.org/Messier/more/ local.html ] galaxy. Andromeda's population of bright young stars define its sweeping spiral arms in visible light images [ http://antwrp.gsfc.nasa.gov/apod/ap051222.html ], but here the infrared view clearly follows the lumpy dust lanes heated by the young stars as they wind even closer to the galaxy's core [ http://antwrp.gsfc.nasa.gov/apod/ap041227.html ]. Constructed to explore [ http://nedwww.ipac.caltech.edu/level5/ANDROMEDA_Atlas/ Hodge_contents.html ] Andromeda's infrared brightness [ http://coolcosmos.ipac.caltech.edu// ] and stellar populations, the full mosaic image is composed of about 3,000 individual frames. Two smaller companion galaxies, NGC 205 [ http://antwrp.gsfc.nasa.gov/apod/ap001023.html ] (below) and M32 [ http://antwrp.gsfc.nasa.gov/apod/ap991103.html ] (above) are also included in the combined fields. The data confirm that Andromeda (aka M31) houses around 1 trillion [ http://kokogiak.com/megapenny/thirteen.asp ] stars, compared to [ http://astronomy.swin.edu.au/~gmackie/billions.html ] 4 hundred billion [ http://kokogiak.com/megapenny/nine.asp ] for the Milky Way. |
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