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M77 & M74
Kyle Loske & William Snoeyink

Galaxy M77 Galaxy M74
M77 - Kyle Loske M74- William Snoeyink

These two objects, M77 and M74, are galaxies. Galaxies are composed of massive numbers of stars that orbit a galactic center. This center is believed to often contain a supermassive black hole. A galaxy is held together by the immense gravity of this central body and orbits it over extended periods. Galaxies are effected in different ways by the tides of their centers gravity, causing differing shapes to emerge. These shapes are catagorized into Spiral, Elliptical, and Irregular Galaxies.

M77 is a barred Spiral Galaxy about 45 million light-years away. The galaxy was discovered by Pierre Mechain, French scientist, in 1780, and was originally believed to be a nebula. It was later reclassified by Charles Messier to be a star cluster, but has since been identified as a galaxy. It is one of the most well documented galaxies. It is the brightest, with a magnitude of 9.6, and closest of the known Seyfert galaxies. The galaxy has an active glactic nucleus that is relatively small for its class of galaxy. The arms are barred and striking in their vividness, and play home to a speckling of active star forming reigions.

M74 was discovered in the constellation of Pices in September of 1780 by Pierre Méchain. Mechain reported this find to his friend Charles Messier, who catalogued it several weeks later. M74 is an example of a Grand Design Spiral Galaxy, spiral galaxies whose spiral arms are well-defined in shape. These well-defined spirals indicate that star formation is ongoing in the galaxy. It is a little smaller than the our own galaxy, the Milky Way, and contains about 100 billion stars. The galaxy’s surface brightness is low, making the galaxy harder to observe. It appears to be about 30 or 40 million light-years away.

M74 and M77 are similar in that they are both Spiral Galaxies. The two galaxies are similar in color, with a yellow center and blue spiral arms. Red pockets can be found in the spiral arms of both galaxies, indicating places where star formation is ongoing. Both galaxies were discovered within a month of each other by the same astronomer.

The object M74 is a grand design spiral galaxy. It lacks a bar, meaning it has no central bar in its construction, and follows a circular pattern. It does not have an active galactic center and is much smaller than M77. Unlike M74, M77 is an active galaxy of the Seyfert class. It has a bar in its arms and exhibits quasar like activity from its central bulge.

References:

Fromert, Hautman, and Christine Kronberg. "Messier Object 74." Students for the Exploration and Development of Space. <http://messier.seds.org/m/m074.html>.

"Grand Design Spiral." Cosmos Encyclopedia of Astronomy. Swinburne University of Technology <http://astronomy.swin.edu.au/cosmos/g/grand+design+spirala>.

Guttridge, Nicky. "Hubble Observes the Hidden Depths of Messier 77." Hubble Space Telescope. <https://www.spacetelescope.org/news/heic1305/>

"Spiral Galaxy." NASA, 16 Dec. 2011.

Wikipedia. Mesier 77.

Object M77 M74
Right Ascension (J2000) 02:42:41 01:36:42
Declination (J2000) -00:00:46 +15:47:00
Filters used B (Blue), R (Red), V (Green) B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B (100 x 4), V (250s), and R (250s) B, V, and R (300s); C (60s x 5)
Image dimension 362x206 pixels; 470x268 arcminutes 576x482 pixels; 749x627 arcminutes
Date/time observed October 15, 2015 October 15, 2015

 

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