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Astr110 Photography Projects, Fall 2006

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Messier Object 74, Megan Ambrose

Messier Object

M74 is considered by some to be a perfect spiral galaxy.  If one doesn't admit to that, they will at least admit it is very photogenic.  M74 is the size of our very own Milky Way, approximately 44,000 light years across, and is located near the constellation Pisces about 30 million light years away.  It is the main attraction of a group of small irregular galaxies, containing about 100 billion stars. Amateur astronomers can have a hard time finding this galaxy due to the low surface brightness of the spiral arms.  The bright central disk is often confused for a star and often classified as such.  In the article “M74: X-rays Signal Presence of Elusive Intermediate-Mass Black Hole” it is stated that the center is actually hot gases surrounding a black hole about the size of 10,000 suns.  This black hole was quite possibly formed as a combination of hundreds of smaller black holes.

The disk surrounding the galaxy is a collection of older stars, which are visible as the small more yellow star clouds surrounding the arms. The arms themselves are comprised of mainly younger stars, which emit a blue glow. The galaxy is a disk with some parts more dense that others. Star formation occurs at these more dense spots.  The pink clouds surrounding the blue stars are a reaction by the surrounding hydrogen to the stars formation. On the inside of each of the spiral arms is a layer of dust creating a dark lane with few stars. The almost perfectly symmetric structure of the galaxy is most likely caused by density waves created from the gravitational interaction with nearby galaxies.

References:
Frommert, Hartmut, and Christine Kronberg. "Messier 74." . 16 Nov. 2005. SEDS. 9 Nov. 2006 <http://www.seds.org/messier/m/m074.html>.

"M74:X-rays Signal Presence of Elusive Intermediate-Mass Black Hole." Photo Album.30 Aug. 2006. Harvard-Smithsonian Center for Astrophysics. 9 Nov. 2006 <http://chandra.harvard.edu/photo/2005/m74/>.

Nemiroff, Robert, and Jerry Bonnell. "M74: A Grand Design Spiral Galaxy." Astronomy Picture of the Day. 9 July 1996. NASA. 6 Nov. 2006
<http://apod.gsfc.nasa.gov/apod/ap960709.html>.

Nemiroff, Robert , and Jerry Bonnell. "M74: The Perfect Spiral." Astronomy Picture of the Day. 24 May 2003. NASA. 9 Nov. 2006 <http://antwrp.gsfc.nasa.gov/apod/ap030524.html>.

 

Right Ascension (J2000) 1:36:42
Declination (J2000) +15:47:00
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter 5x60 seconds in C, 300 seconds in BVR
Date observed

October 18, 2006