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Multiwavelength Surveys
The Multiwavelength Atlas of Galaxies is a textbook and atlas of 35 well studied galaxies (including our Galaxy) authored by Glen Mackie of the Centre for Astrophysics & Supercomputing, Swinburne University of Technology. It was originally published in 2011 by Cambridge University Press. Atlas scope The purpose of the atlas is to display and describe some of the best multiwavelength images of galaxies. The images originate from a variety of telescopes, instruments and detectors, and therefore possess wide ranges of signal-to-noise, angular resolution, sampling or pixel sizes and fields of view. The atlas is a compendium of galaxy images spanning the Gamma ray, X-ray, Ultraviolet, Optical, Infrared, Submillimeter and Radio regions of the electromagnetic spectrum. The atlas has been favourably reviewed in the Royal Astronomical Society journal, Astronomy & Geophysics. Creating the atlas was a long term project ten years in the making. Background on the genesis of the atlas can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Textbook
A textbook is a book containing a comprehensive compilation of content in a branch of study with the intention of explaining it. Textbooks are produced to meet the needs of educators, usually at educational institutions. Schoolbooks are textbooks and other books used in schools. Today, many textbooks are published in both print and digital formats. History The history of textbooks dates back to ancient civilizations. For example, Ancient Greeks wrote educational texts. The modern textbook has its roots in the mass production made possible by the printing press. Johannes Gutenberg himself may have printed editions of ''Ars Minor'', a schoolbook on Latin grammar by Aelius Donatus. Early textbooks were used by tutors and teachers (e.g. alphabet books), as well as by individuals who taught themselves. The Greek philosopher Socrates lamented the loss of knowledge because the media of transmission were changing. Before the invention of the Greek alphabet 2,500 years ago, knowledge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 1399
NGC 1399 is a large elliptical galaxy in the Southern constellation Fornax, the central galaxy in the Fornax Cluster. The galaxy is 66 million light-years away from Earth. With a diameter of 130 000 light-years, it is one of the largest galaxies in the Fornax Cluster and slightly larger than the Milky Way. William Herschel discovered this galaxy on October 22, 1835. Characteristics It is a type- cD galaxy, with a bright center and a vast, diffuse envelope surrounding it. It is also an early-type galaxy, the largest one in the Fornax Cluster. Despite their name, early-type galaxies are much older than spiral galaxies, and mostly comprise old, red-colored stars. Very little star formation occurs in these galaxies; the lack of star formation in elliptical galaxies appears to start at the center and then slowly propagates outward. Globular clusters NGC 1399 is very rich in globular clusters. The population is estimated to be between 5700 and 6500. It has been proposed th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perseus Cluster
The Perseus cluster (Abell 426) is a cluster of galaxies in the constellation Perseus. It has a recession speed of 5,366 km/ s and a diameter of 863′. It is one of the most massive objects in the known universe, containing thousands of galaxies immersed in a vast cloud of multimillion-degree gas. X-radiation from the cluster The detection of X-ray emission from Per XR-1 occurred during an Aerobee rocket flight on March 1, 1970, the source may be associated with NGC 1275 (Per A, 3C 84), and was reported in 1971. If the source is NGC 1275, Lx ~4 x 1045 ergs/s. More detailed observations from Uhuru confirmed the earlier detection and associated the source with the Perseus cluster. Per X-1 is the galaxy cluster at 4U 0316+41 designated the Perseus cluster, Abell 426, and NGC 1275. The galaxy cluster is the brightest cluster in the sky when observed in the X-ray band. The cluster contains the radio source 3C 84 that is currently blowing bubbles of relativistic plasma i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 1275
NGC 1275 (also known as Perseus A or Caldwell 24) is a type 1.5 Seyfert galaxy located around 237 million light-years away in the direction of the constellation Perseus. NGC 1275 corresponds to the radio galaxy Perseus A and is situated near the center of the large Perseus Cluster of galaxies. Properties NGC 1275 consists of two galaxies, a central type-cD galaxy in the Perseus Cluster, and a so-called "high velocity system" (HVS) which lies in front of it. The HVS is moving at 3000 km/s towards the dominant system, and is believed to be merging with the Perseus Cluster. The HVS is not affecting the cD galaxy as it lies at least 200 thousand light years from it. However tidal interactions are disrupting it and ram-pressure stripping produced by its interaction with the intracluster medium of Perseus is stripping its gas as well as producing large amounts of star formation within it The central cluster galaxy contains a massive network of spectral line emitting filaments ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 520
NGC 520 is a pair of colliding spiral galaxies about 105 million light-years away in the constellation Pisces. They were discovered by astronomer William Herschel on 13 December 1784. Halton Arp called this the second-brightest very disturbed galaxy in the sky, and it is as bright in the infrared and radio bands as the Antennae Galaxies. Simulations indicate this object consists of two galactic disks that began interacting about 300 million years ago. The system is still in an early stage of its merger, showing two separate velocity systems in the spectra, and two small tails. Two galactic nuclei have been detected, and one is an H II nucleus. The main galactic component is being viewed edge-on, making it fainter in the optical band. The secondary component is brighter but less massive than the main, and is located to the northwest. They are separated by a dark lane of dust. The region of the galaxies outside their nuclei experienced a period of increased star formation rou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whirlpool Galaxy
The Whirlpool Galaxy, also known as Messier 51a, M51a, and NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellation Canes Venatici, and was the first galaxy to be classified as a spiral galaxy. Its distance is 31 million light-years from Earth. The galaxy and its companion, NGC 5195, are easily observed by amateur astronomers, and the two galaxies may be seen with binoculars. The Whirlpool Galaxy has been extensively observed by professional astronomers, who study it to understand galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions. Discovery What later became known as the Whirlpool Galaxy was discovered on October 13, 1773, by Charles Messier while hunting for objects that could confuse comet hunters, and was designated in Messier's catalogue as M51. Its companion galaxy, NGC 5195, was discovered in 1781 by Pierre Méchain, although it was not known wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mice Galaxies
NGC 4676, or the Mice Galaxies, are two spiral galaxies in the constellation Coma Berenices. About 290 million light-years distant, they have begun the process of colliding and merging. Their name refers to the long tails produced by tidal action—the relative difference between gravitational pulls on the near and far parts of each galaxy—known here as a galactic tide. It is a possibility that both galaxies, which are members of the Coma Cluster, have experienced collision, and will continue colliding until they coalesce. The colors of the galaxies are peculiar. In NGC 4676A a core with some dark markings is surrounded by a bluish white remnant of spiral arms. The tail is unusual, starting out blue and terminating in a more yellowish color, despite the fact that the beginning of each arm in virtually every spiral galaxy starts yellow and terminates in a bluish color. NGC 4676B has a yellowish core and two arcs; arm remnants underneath are bluish as well. The galaxies were photo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 49
Messier 49 (also known as M49 or NGC 4472) is a giant elliptical galaxy about away in the equatorial constellation of Virgo. This galaxy was discovered by astronomer Charles Messier in 1777. As an elliptical galaxy, Messier 49 has the physical form of a radio galaxy, but it only has the radio emission of a normal galaxy. From the detected radio emission, the core region has roughly 1053 erg (1046 J or 1022 YJ) of synchrotron energy. The nucleus of this galaxy is emitting X-rays, suggesting the likely presence of a supermassive black hole with an estimated mass of , or 565 million times the mass of the Sun (). X-ray emissions shows a structure to the north of Messier 49 that resembles a bow shock. To the southwest of the core, the luminous outline of the galaxy can be traced out to a distance of 260 kpc. The only supernova event seen within it is SN 1969Q, discovered in 1969. This galaxy has many globular clusters: estimated to be about 5,900. This is far more than the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virgo Cluster
The Virgo Cluster is a large cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the constellation Virgo. Comprising approximately 1,300 (and possibly up to 2,000) member galaxies, the cluster forms the heart of the larger Virgo Supercluster, of which the Local Group (containing our Milky Way galaxy) is a member. The Local Group actually experiences the mass of the Virgo Supercluster as the Virgocentric flow. It is estimated that the Virgo Cluster's mass is 1.2 out to 8 degrees of the cluster's center or a radius of about 2.2 Mpc. Many of the brighter galaxies in this cluster, including the giant elliptical galaxy Messier 87, were discovered in the late 1770s and early 1780s and subsequently included in Charles Messier's catalogue of non-cometary fuzzy objects. Described by Messier as nebulae without stars, their true nature was not recognized until the 1920s. The cluster subtends a maximum arc of approximately 8 degrees centered in the constellati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 86
Messier 86 (also known as M86 or NGC 4406) is an elliptical or lenticular galaxy in the constellation Virgo. It was discovered by Charles Messier in 1781. M86 lies in the heart of the Virgo Cluster of galaxies and forms a most conspicuous group with another large galaxy known as Messier 84. It displays the highest blue shift of all Messier objects, as it is, net of its other vectors of travel, approaching the Milky Way at 244 km/s. This is due to both galaxies falling roughly towards the center of the Virgo cluster from opposing ends. Messier 86 is linked by several filaments of ionized gas to the severely disrupted spiral galaxy NGC 4438, indicating that M86 may have stripped some gas and interstellar dust from the spiral. It is also suffering ram-pressure stripping as it moves at high speed through Virgo's intracluster medium, losing its interstellar medium and leaving behind a very long trail of X ray-emitting hot gas that has been detected with the help of the Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 6822
NGC 6822 (also known as Barnard's Galaxy, IC 4895, or Caldwell 57) is a barred irregular galaxy approximately 1.6 million light-years away in the constellation Sagittarius. Part of the Local Group of galaxies, it was discovered by E. E. Barnard in 1884 (hence its name), with a six-inch refractor telescope. It is the closest non-satellite galaxy to the Milky Way, but lies just outside its virial radius. It is similar in structure and composition to the Small Magellanic Cloud. It is about 7,000 light-years in diameter. Observational history NGC 6822 was discovered by E. E. Barnard in 1884 using a six-inch refractor telescope. Edwin Hubble, in the paper ''N.G.C. 6822, A Remote Stellar System'', identified 15 variable stars (11 of which were Cepheids) of this galaxy. He also surveyed the galaxy's stars distribution down to magnitude 19.4. He provided spectral characteristics, luminosities and dimensions for the five brightest " diffuse nebulae" (giant H II regions) that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinwheel Galaxy
The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy away from Earth in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 and was communicated that year to Charles Messier, who verified its position for inclusion in the '' Messier Catalogue'' as one of its final entries. On February 28, 2006, NASA and the European Space Agency released a very detailed image of the Pinwheel Galaxy, which was the largest and most-detailed image of a galaxy by Hubble Space Telescope at the time. The image was composed of 51 individual exposures, plus some extra ground-based photos. On August 24, 2011, a Type Ia supernova, SN 2011fe, was discovered in M101. Discovery Pierre Méchain, the discoverer of the galaxy, described it as a "nebula without star, very obscure and pretty large, 6' to 7' in diameter, between the left hand of Bootes and the tail of the great Bear. It is difficult to distinguish when one lits the ratingwires. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
