The Antennae Galaxies are known as interacting galaxies as they are currently undergoing a galactic collision. They are known for their distinct tails of stars, gas, and dust that have been emitted from the galaxies as they undergo collision. Over time however, the galaxies will merge as one becoming a much more massive galaxy when their nuclei join as one. This will eventually be seen in the Milky Way Galaxy when it collides with Andromeda billions of years from now.
Within the Antennae galaxies are large globular clusters of stars that were made from the collision. They are about 12 billion years old and likely were created by the shockwaves caused from the collision. However, 1.2 billion years ago, these galaxies were separate. NGC 4038, the larger component of the two, was a barred spiral galaxy, and NGC 4039, the smaller component, was a spiral galaxy. Then 600 million years ago the two galaxies passed through each other, and finally 300 million years ago started to eject stars out giving its distinct shape. It is predicted the galaxies will finally become one in around 400 million years, and will become an elliptical galaxy. Source: "Antennae Galaxies." Wikipedia. Wikimedia Foundation, 17 Feb. 2017. Web. 01 Mar. 2017. <https://en.wikipedia.org/wiki/Antennae_Galaxies>.
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The Whirlpool Galaxy (M51) is ideal for Northern Hemisphere viewers. It is visible through binoculars in dark conditions, as well as with amateur telescopes. This galaxy is a spiral galaxy about 15-35 million light years away and was actually the first galaxy to be identified as a spiral galaxy! It is 35 percent the size of the Milky Way. As seen in the processed picture below, M51 has a dwarf galaxy sharing material with the spiral galaxy, known as NGC 5195. This dwarf galaxy passed through the main disk of M51 about 500 to 600 million years ago. It was predicted that NGC 5195 came from behind M51 and passed through the main disk, then again making another disk crossing anywhere from 50 to 100 million years ago. Now it is located where it can be seen now a little bit behind M51. This dynamic duo is studied specifically for galaxy structure. It is expected that the center of M51 is a black hole surrounded by rings of dust. These secondary rings cross the primary rings of the spiral nebula on a different axis, this is a phenomenon as it is unique from many studied spiral galaxies. Ionization cones (emission of photons from nuclear activity in the galaxy) extend out from the primary rings of the spiral galaxy. Star formation is strongly active in the center of the galaxy as well. It’s center is currently undergoing a period of enhanced star formation. This high rate cannot last more than 100 million years. This high pressure of hydrogen from stars can be seen in the bright blue knots in the spiral arms.
History: The Whirlpool galaxy was discovered by Charles Messier on October 13, 1773 and NGC 5195 was discovered in 1981 by Pierre Me’chain. However in 1855 William Parsons discovered the Whirlpool galaxy’s spiral structure, which made it the first ‘nebula’ (what people called galaxies in the past) known to have that structure. https://en.wikipedia.org/wiki/Ionization_cone https://en.wikipedia.org/wiki/Whirlpool_Galaxy The Pinwheel Galaxy, located in the constellation Ursa Major, is a spiral galaxy twice the size of the Milky Way. It has a diameter of 170,000 lys and a distance of 21 million ly. It was discovered in 1781 by Pierre Méchain of Spain who collaborated with Charles Messier to create the Messier catalog, which is a catalog of discovered deep space objects. M101 in particular stands out from other galaxies. Many galaxies have massive black holes in the center of their galaxies. However, there has yet to be a black hole discovered in the Pinwheel Galaxy. The galaxy also has many x-rays ejected by exploding stars and black holes located in the galaxy. One part of the galaxy, known as P98 was even designated an ultra-luminous x-ray source, which means it is more powerful than a solo star, but less powerful than an entire galaxy. Along with much of the galaxy appearing in the x-ray spectrum, the galaxy is also home to over 3,000 star nurseries in the spirals of M101 where copious amounts of Hydrogen exist, called HII regions. These regions are ionized in result of the extremely hot and bright stars.
Because of the surrounding galaxies accompanying M101, the Pinwheel Galaxy is asymmetric. The gravitational forces conflicting the galaxy compress the hydrogen gas in M101 which causes the star formation, or those HII regions. Not only is the Pinwheel Galaxy fascinating, it is also beautiful! NASA Administrator. "The Pinwheel Galaxy." NASA. NASA, 31 May 2012. Web. 26 Jan. 2017. <https://www.nasa.gov/multimedia/imagegallery/image_feature_2265.html>. "Pinwheel Galaxy Facts." Space Facts. SpaceFacts2017, 23 June 2016. Web. 26 Jan. 2017. <http://space-facts.com/pinwheel-galaxy/>. "Pinwheel Galaxy." Wikipedia. Wikimedia Foundation, 17 Jan. 2017. Web. 26 Jan. 2017. <https://en.wikipedia.org/wiki/Pinwheel_Galaxy>. The pictures below were some of my work from last year. However, what I did not do was give a little insight to put the galaxy into context. The Andromeda Galaxy is very special because it is our neighbor! Like the Milky Way, the Andromeda Galaxy is a spiral galaxy and is the largest galaxy in the Local Group, which consists of many dwarf galaxies, as well as the Milky Way and the Triangulum galaxy. In some dark places, Andromeda can even be seen with the naked eye! The galaxy is about 260,000 lightyears (ly) across and can be found 2.5 millions ly away!
Although right now the Milky Way and the Andromeda galaxy are millions of light years away, soon enough it will not be that way. Because of blue shift, Andromeda and the Milky Way are rushing towards each other at 70 miles per second, predicting a collision is approximately 5 billion years, creating one massive elliptical galaxy. History: In the 1920s, Andromeda was the subjects of a "Great Debate." Two astronomers, Harlow Shapley and Heber Curtis had conflicting views on if the Andromeda galaxy was or was not a part of the Milky Way. During this time, most astronomer believed the entirety of the Universe was solely the Milky Way. However, Curtis observed fluxes in light in Andromeda convincing him it was it's own galaxy. The two men continued to argue until the famous Edwin Hubble found the answer they were looking for in 1925. Hubble discovered Cepheid variable stars which were stars that were used for accurate measurements of distance inside Andromeda. Hubble calculated Andromeda was too far away to be within the Milky Way when he put them into perspective with Shapley's calculation that the Milky Way was only 100,00 ly across. Thus, Curtis was right. Source: Redd, Nola Taylor. "Andromeda Galaxy (M31): Location, Characteristics & Images." Space.com. Purch, 8 May 2012. Web. 09 Jan. 2017. <http://www.space.com/15590-andromeda-galaxy-m31.html>. Update: Soon this blog will have an update of my second rendition of the Andromeda Galaxy! |
AuthorPassionante amateur astronomer| 18| Pomfret '17| BU '21 |