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Spiral Galaxy (NGC 7331) & Spiral Galaxy (NGC 1068)
Emma DeWitt & Evan Jewell

Spiral Galaxy NGC 1068
Galaxy NGC 7331- Emma DeWitt Galaxy NGC 1068- Evan Jewell

The two images above are spiral galaxies, which is a type of galaxy that Edwin Hubble first described in his 1936 work The Realm of the Nebulae. These types of galaxies have a thin disk that surrounds a bulge in the center, and that central bulge can extend to a radius of over 100,000 light years. (The Cosmic Perspective Fundamentals, 2010) Some spiral galaxies can be tightly wounded, and some are looser. About 80% of all galaxies are spiral galaxies, and most of the time they are found in galaxy clusters of around dozen galaxies. The Milky Way (the galaxy that we live in) is also a spiral galaxy!

NGC 7331, also known as Caldwell 30, discovered 200 years ago by William Herschel, was first recognized as a spiral nebula, but it is now recognized as a galaxy that is related to our galaxy, the Milky Way. ("Astronomy Picture of the Day", 2014) This galaxy can be seen with only the use of binoculars because of its distance to earth. This galaxy was one of Herschel's earliest discoveries. It is the brightest galaxy in the Pegasus constellation, and like many other spiral galaxies, it has a neighboring galaxy that is much fainter. The magnitude of NGC 7331 is 10.3, it is 43 million light years away from our galaxy, and it has a diameter of 132,341 light years. ("Spiral Galaxy NGC 7331", 2008)

NGC 1068, also known as Messier 77 or M77, is a Seyfert 2 spiral galaxy located in the constellation Cetus. It was initially observed by Pierre Mechain on October 29, 1780, who described it as a nebula. It was later misclassified as a cluster with nebulosity. Recent observations have suggested that it contains a very bright, active type 1 nucleus, with strong emission lines due to large amounts of excited gas near the core, though an obscuring ring or torus of material blocks it from our direct view. The galaxy also displays a bright nuclear region, faint spiral arms, and highly ionized gases which form a cone-like illumination pattern.

Both of these galaxies are spiral galaxies, and they are fairly similar in a few ways. They both are about the same magnitude (with a variation of less than 1). In fact, they are both the largest galaxies in their clusters. Both galaxies were also discovered around the same time. Both Messier (discovered NGC 1068) and Herschel (discovered NGC 7331) were living and discovering galactic objects when these galaxies were discovered.

However these galaxies are also different in many ways. For example, NGC 1068 is more circular, whereas NGC 7331 is more ovular shaped. Furthermore, they are found in different constellations. NGC 1068 is in the Cetus constellation, discovered by Messier, and NGC 7331 is found in the Pegasus constellation, discovered by Herschel. Some spiral galaxies are much tighter than others which is exemplified through these two galaxies. NGC 1068 seems to be a much tighter galaxy than NGC 7331. And last, the color tint of these two objects are much different. NGC 7331 has much more of a blue tint to it, and NGC 1068 is more of a pinkish/ purple color.

References:

"Galaxy, Jet, and Obscuring Disk in NGC 1068." Active Galaxies and Quasars. N.p., n.d. Web.

Nemiroff, Robert, and Jerry Bonnell. "Astronomy Picture of the Day." APOD: 2014 March 1. NASA Web

Privacy Policy and Important Notices, 1 Mar. 2014. Web. 03 Dec. 2015.

Normandin, George. "Spiral Galaxy M-77." Kopernik. N.p., 26 Mar. 2007. Web.

Normandin, George. "Spiral Galaxy NGC 7331." Kopernik. N.p., 28 Oct. 2008. Web.

"Messier 77." Messier Object 77. N.p., n.d. <http://messier.seds.org/m/m077.html>.

"M77 NGC 1068." M77 NGC 1068. N.p., n.d. Web.

Object Spiral Galaxy NGC 7331 NGC 1068
Right Ascension (J2000) 22:37:5.102  
Declination (J2000) -34:25:12.9  
Filters used B (Blue), C (Clear), R (Red), V (Green)  
Exposure time per filter B(450s), V(225s), and R (225s); C (60s x 5)  
Image dimension 1092x736 pixels; 23.8x16.1 arcminutes  
Date/time observed September 30, 2015, 12:05 UT  

 

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