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Far 3 Kpc Arm
The Far 3 kpc Arm was discovered in 2008 by astronomer Tom Dame ( Center for Astrophysics Harvard & Smithsonian), while preparing a talk on the galaxy's spiral arms for a meeting of the 212th American Astronomical Society. It is one of Milky Way's spiral arms and it is located in the first galactic quadrant at a distance of from the Galactic Center. Along with the Near 3 kpc Arm, the existence of which has been known since the mid-1950s, the counterpart inner arms establish our Galaxy's simple symmetry. Tom Dame and collaborator Patrick Thaddeus analyzed data obtained using a 1.2-meter-diameter millimeter-wave telescope located at Cerro Tololo Inter-American Observatory (CTIO) in Chile. They detected the presence of the spiral arm in a CO survey and later confirmed their discovery using 21-centimeter radio measurements of atomic hydrogen collected by colleagues in Australia. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patrick Thaddeus
Patrick Thaddeus (June 6, 1932 – April 28, 2017) was an American professor and the Robert Wheeler Willson Professor of Applied Astronomy Emeritus at Harvard University. He is best known for mapping carbon monoxide in the Milky Way galaxy and was responsible for the construction of the CfA 1.2 m Millimeter-Wave Telescope. Early life He was born on June 6, 1932, to Elizabeth and Victor Thaddeus. His mother divorced Thaddeus when he and his sister, Deirdre, were very young. She later remarried to Vincent Copeland. Education Thaddeus graduated from University of Delaware in 1953 with a Bachelor of Science degree. He was awarded a Fulbright Fellowship through which he attended the University of Oxford, graduating with a Master's degree in theoretical physics in 1955. His doctoral work was at Columbia University, where he earned his Ph.D. under Charles Hard Townes in 1960 with a thesis titled ''Beam Maser Spectroscopy''. Career After earning his doctorate, Thaddeus stayed at Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milky Way Arms
Milky is an Italian dance music production group consisting of producers Giordano Trivellato and Giuliano Sacchetto, with Italian singer Giuditta serving as their lead singer on their album ''Star''. Although Giuditta Gazza was the singer on the recordings, a model, the Egyptian-born and German-raised Sabrina Elahl, was used for the music video for the " Just the Way You Are" single. The same model was used for the cover. Elahl's voice did not appear on any of Milky's recordings, where all songs were sung by Giuditta. Giuditta can be seen on the " [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactic Disc
A galactic disc (or galactic disk) is a component of disc galaxies, such as spiral galaxies and lenticular galaxies. Galactic discs consist of a stellar component (composed of most of the galaxy's stars) and a gaseous component (mostly composed of cool gas and dust). The stellar population of galactic discs tend to exhibit very little random motion with most of its stars undergoing nearly circular orbits about the galactic center. Discs can be fairly thin because the disc material's motion lies predominantly on the plane of the disc (very little vertical motion). The Milky Way's disc, for example is approximately 1 kly thick but thickness can vary for discs in other galaxies. Stellar component Exponential surface brightness profiles Galactic discs have surface brightness profiles that very closely follow exponential functions in both the radial and vertical directions. Radial profile The surface brightness radial profile Radial is a geometric term of location which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Line
The hydrogen line, 21 centimeter line, or H I line is the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This electromagnetic radiation has a precise frequency of , which is equivalent to the vacuum wavelength of in free space. This frequency falls below the microwave region of the electromagnetic spectrum, which begins at 3.0 GHz (10 cm wavelength), and it is observed frequently in radio astronomy because those radio waves can penetrate the large clouds of interstellar cosmic dust that are opaque to visible light. This line is also the theoretical basis of the hydrogen maser. The microwaves of the hydrogen line come from the atomic transition of an electron between the two hyperfine levels of the hydrogen 1 s ground state that have an energy difference of []. It is called the ''spin-flip transition''. The frequency, , of the quantum, quanta that are emitted by this transition bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Monoxide
Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simplest molecule of the oxocarbon family. In coordination complexes the carbon monoxide ligand is called carbonyl. It is a key ingredient in many processes in industrial chemistry. The most common source of carbon monoxide is the partial combustion of carbon-containing compounds, when insufficient oxygen or heat is present to produce carbon dioxide. There are also numerous environmental and biological sources that generate and emit a significant amount of carbon monoxide. It is important in the production of many compounds, including drugs, fragrances, and fuels. Upon emission into the atmosphere, carbon monoxide affects several processes that contribute to climate change. Carbon monoxide has important biological roles across phylog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerro Tololo Inter-American Observatory
The Cerro Tololo Inter-American Observatory (CTIO) is an astronomical observatory located on Cerro Tololo in the Coquimbo Region of northern Chile, with additional facilities located on Cerro Pachón about to the southeast. It is approximately east of La Serena, where support facilities are located. The site was identified by a team of scientists from Chile and the United States in 1959, and it was selected in 1962. Construction began in 1963 and regular astronomical observations commenced in 1965. Construction of large buildings on Cerro Tololo ended with the completion of the Víctor Blanco Telescope in 1974, but smaller facilities have been built since then. Cerro Pachón is still under development, with two large telescopes (Gemini South and SOAR) inaugurated since 2000, and one in the early stages of construction (the Vera C. Rubin Observatory) The principal telescopes at CTIO are the 4 m Víctor M. Blanco Telescope, named after Puerto Rican astronomer Víctor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, the word ''telescope'' now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. The first known practical telescopes were refracting telescopes with glass lenses and were invented in the Netherlands at the beginning of the 17th century. They were used for both terrestrial applications and astronomy. The reflecting telescope, which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. Etymology The word ''telescope'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Near 3 Kpc Arm
The Near 3 kpc Arm (also called Expanding 3 kpc Arm or simply 3 kpc Arm) was discovered in the 1950s by astronomer van Woerden and collaborators through 21-centimeter radio measurements of HI (atomic hydrogen).A New Spiral Arm of the Galaxy: The Far 3-Kpc Arm T. M. Dame, P. Thaddeus, ''ApJ Letters'', 2008 It was found to be expanding away from the center of the at more than 50 . This contains about 10 million |
Tom Dame
Thomas M. Dame is Director of the Radio Telescope Data Center at the Center for Astrophysics Harvard & Smithsonian, a Senior Radio Astronomer at the Smithsonian Astrophysical Observatory, and a Lecturer on Astronomy at Harvard University. He is best known for mapping the Milky Way galaxy in Carbon Monoxide and for the discovery of both the Far 3 kpc Arm and the Outer Scutum–Centaurus Arm of the Milky Way. Education Dame graduated from Boston University in 1976 with a BA in Astronomy and Physics. He earned his Master's degrees and Ph.D. from Columbia University. His dissertation, earned under Patrick Thaddeus in 1983, was titled ''Molecular Clouds and Galactic Spiral Structure ''. Career After earning his doctorate, Dame worked as the National Research Council resident research associate at the Goddard Institute for Space Studies from 1983 to 1984 and then as a research associate at the Columbia University Department of Astronomy. He moved to Harvard University with Thaddeus in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactic Center
The Galactic Center or Galactic Centre is the rotational center, the barycenter, of the Milky Way galaxy. Its central massive object is a supermassive black hole of about 4 million solar masses, which is called Sagittarius A*, a compact radio source which is almost exactly at the galactic rotational center. The Galactic Center is approximately away from Earth in the direction of the constellations Sagittarius, Ophiuchus, and Scorpius, where the Milky Way appears brightest, visually close to the Butterfly Cluster (M6) or the star Shaula, south to the Pipe Nebula. There are around 10 million stars within one parsec of the Galactic Center, dominated by red giants, with a significant population of massive supergiants and Wolf–Rayet stars from star formation in the region around 1 million years ago. The core stars are a small part within the much wider galactic bulge. Discovery Because of interstellar dust along the line of sight, the Galactic Center cannot b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactic Quadrant
A galactic quadrant, or quadrant of the Galaxy, is one of four circular sectors in the division of the Milky Way Galaxy. Quadrants in the galactic coordinate system In actual astronomical practice, the delineation of the galactic quadrants is based upon the galactic coordinate system, which places the Sun as the pole of the mapping system. The Sun is used instead of the Galactic Center for practical reasons since all astronomical observations (by humans) to date have been based on Earth or within the Solar System. Delineation Quadrants are described using ordinals—for example, "1st galactic quadrant" "second galactic quadrant," or "third quadrant of the Galaxy."M. Lampton ''et al''An All-Sky Catalog of Faint Extreme Ultraviolet Sources''The Astrophysical Journal Supplement Series ''. 1997 Viewing from the north galactic pole with 0 degrees (°) as the ray that runs starting from the Sun and through the galactic center, the quadrants are as follows (where is galactic l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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