M104: The Sombrero Galaxy [NASA photograph]; LG-2004-6-084-GSFC
Goddard Space Flight Center: National Astronautics and Space Administration, Goddard Space Flight Center, 2004. Presumed First Edition, First printing, this is one of multiple originals issued. Single sheet, printed on both sides. The format is approximately 8 inches by 10 inches. This is a single sheet, with printing/imagery on both sides, in a plastic sleeve. On the front side is a large color photograph of the Sombrero Galaxy. The other side is in a two-column format. There are several images of the galaxy on the left side. NASA and the Hubble Heritage Team (STScl/AURA) is credited for this imagery. The text on the back side includes "Hats Off" to the Sombrero Galaxy, Vocabulary, Fast Facts, and Looks are Deceiving. This galaxy's most striking feature is the dust lane that crosses in front of the bulge of the galaxy. This dust lane is actually a symmetrical ring that encloses the bulge of the galaxy. Most of the cold atomic hydrogen gas and the dust lie within this ring. The ring might also contain most of the Sombrero Galaxy's cold molecular gas, although this is an inference based on observations with low resolution and weak detections. Additional observations are needed to confirm that the Sombrero galaxy's molecular gas is constrained to the ring. Based on infrared spectroscopy, the dust ring is the primary site of star formation within this galaxy. The Sombrero Galaxy (also known as Messier Object 104, M104 or NGC 4594) is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs (31.1 million light-years) from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has an isophotal diameter of approximately 29.09 to 32.32 kiloparsecs (94,900 to 105,000 light-years), making it slightly bigger in size than the Milky Way. It has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its outer disk, which is viewed almost edge-on. The dark dust lane and the bulge give it the appearance of a sombrero hat (thus the name). Astronomers initially thought the halo was small and light, indicative of a spiral galaxy; but the Spitzer Space Telescope found that the dust ring was larger and more massive than previously thought, indicative of a giant elliptical galaxy. The galaxy has an apparent magnitude of +8.0, making it easily visible with amateur telescopes, and is considered by some authors to be the galaxy with the highest absolute magnitude within a radius of 10 megaparsecs of the Milky Way. Its large bulge, central supermassive black hole, and dust lane all attract the attention of professional astronomers. The Sombrero Galaxy was discovered on May 11, 1781 by Pierre Méchain, who described the object in a May 1783 letter to J. Bernoulli that was later published in the Berliner Astronomisches Jahrbuch. Charles Messier made a handwritten note about this and five other objects (now collectively recognized as M104 – M109) to his personal list of objects now known as the Messier Catalogue, but it was not "officially" included until 1921. William Herschel independently discovered the object in 1784 and additionally noted the presence of a "dark stratum" in the galaxy's disc, what is now called a dust lane Later astronomers were able to connect Méchain's and Herschel's observations. In 1921, Camille Flammarion found Messier's personal list of the Messier objects including the hand-written notes about the Sombrero Galaxy. This was identified with object 4594 in the New General Catalogue, and Flammarion declared that it should be included in the Messier Catalogue. Since this time, the Sombrero Galaxy has been known as M104. Condition: Very good.
Keywords: Sombrero Galaxy, Messier Object 104, M104, NGC 4594, Globular Cluster, Spiral Galaxy, Messier Catalogue, Constellation Virgo, Hubble Space Telescope, Astronomy
[Book #86152]
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