Atacama Large Millimeter Array

The Atacama Large Millimeter/submillimeter Array is an astronomical interferometer of 66 radio telescopes in the Atacama Desert of northern Chile, which observe electromagnetic radiation at millimeter and submillimeter wavelengths. The array has been constructed on the 5,000 m elevation Chajnantor plateau - near the Llano de Chajnantor Observatory and the Atacama Pathfinder Experiment; this location was chosen for its high elevation and low humidity, factors which are crucial to reduce noise and decrease signal attenuation due to Earth's atmosphere. ALMA is expected to provide insight on star birth during the early Stelliferous era and detailed imaging of local star and planet formation. ALMA is an international partnership among Europe, the United States, Japan, South Korea and Chile. Costing about US$1.4 billion, it is the most expensive ground-based telescope in operation. ALMA began scientific observations in the second half of 2011 and the first images were released to the press on 3 October 2011.

The array has been operational since March 2013. The initial ALMA array is composed of 66 high-precision antennas, operates at wavelengths of 0.32 to 3.6 millimeters. The array has much higher sensitivity and higher resolution than earlier submillimeter telescopes such as the single-dish James Clerk Maxwell Telescope or existing interferometer networks such as the Submillimeter Array or the Institut de Radio Astronomie Millimétrique Plateau de Bure facility; the antennas can be moved across the desert plateau over distances from 150 m to 16 km, which will give ALMA a powerful variable "zoom", similar in its concept to that employed at the centimetre-wavelength Very Large Array site in New Mexico, United States. The high sensitivity is achieved through the large numbers of antenna dishes that will make up the array; the telescopes were provided by the European, North American and East Asian partners of ALMA. The American and European partners each provided twenty-five 12-meter diameter antennas, that compose the main array.

The participating East Asian countries are contributing 16 antennas in the form of the Atacama Compact Array, part of the enhanced ALMA. By using smaller antennas than the main ALMA array, larger fields of view can be imaged at a given frequency using ACA. Placing the antennas closer together enables the imaging of sources of larger angular extent; the ACA works together with the main array in order to enhance the latter's wide-field imaging capability. ALMA has its conceptual roots in three astronomical projects — the Millimeter Array of the United States, the Large Southern Array of Europe, the Large Millimeter Array of Japan; the first step toward the creation of what would become ALMA came in 1997, when the National Radio Astronomy Observatory and the European Southern Observatory agreed to pursue a common project that merged the MMA and LSA. The merged array combined the sensitivity of the LSA with the frequency coverage and superior site of the MMA. ESO and NRAO worked together in technical and management groups to define and organize a joint project between the two observatories with participation by Canada and Spain.

A series of resolutions and agreements led to the choice of "Atacama Large Millimeter Array", or ALMA, as the name of the new array in March 1999 and the signing of the ALMA Agreement on 25 February 2003, between the North American and European parties. Following mutual discussions over several years, the ALMA Project received a proposal from the National Astronomical Observatory of Japan whereby Japan would provide the ACA and three additional receiver bands for the large array, to form Enhanced ALMA. Further discussions between ALMA and NAOJ led to the signing of a high-level agreement on 14 September 2004 that makes Japan an official participant in Enhanced ALMA, to be known as the Atacama Large Millimeter/submillimeter Array. A groundbreaking ceremony was held on November 6, 2003 and the ALMA logo was unveiled. During an early stage of the planning of ALMA, it was decided to employ ALMA antennas designed and constructed by known companies in North America and Japan, rather than using one single design.

This was for political reasons. Although different approaches have been chosen by the providers, each of the antenna designs appears to be able to meet ALMA's stringent requirements; the components designed and manufactured across Europe were transported by specialist aerospace and astrospace logistics company Route To Space Alliance, 26 in total which were delivered to Antwerp for onward shipment to Chile. ALMA was a 50-50 collaboration between the National Radio Astronomy Observatory and European Southern Observatory and extended with the help of the other Japanese and Chilean partners. ALMA is the largest and most expensive ground-based astronomical project, costing between US$1.4 and 1.5 billion.. PartnersEuropean Southern Observatory and the European Regional Support Centre National Science Foundation via the National Radio Astronomy Observatory and the North American ALMA Science Center National Research Council of Canada National Astronomical Observatory of Japan under the National Institutes of Natural Sciences ALMA-Taiwan at the Academia Sinica Institute of Astronomy & Astrophysics Republic of Chile The complex was built by European, U.

S. Japanese, Canadian c

Ptolemy Ceraunus

Ptolemy Ceraunus was a member of the Ptolemaic dynasty and king of Macedon. As the son of Ptolemy I Soter, he was heir to the throne of Ptolemaic Egypt, but he was displaced in favour of his younger brother Ptolemy II Philadelphus, he fled to King Lysimachus of Thrace and Macedon where he was involved in court intrigue that led to the fall of that kingdom in 281 BC to Seleucus I, whom he assassinated. He seized the throne of Macedon, which he ruled for seventeen months before his death in battle against the Gauls in early 279 BC, his epithet Ceraunus is Greek for "Thunderbolt" and referred to his impatient and destructive character. Ptolemy was the eldest son of Ptolemy I Soter, King of Egypt, his first wife Eurydice, daughter of Antipater, regent of Macedon, he was born in 319 BC, soon after his parents' marriage - the first of their six children. Sometime between 317 and 314 BC, Ptolemy I married one of Eurydice's ladies-in-waiting and had further children, including another son - the future Ptolemy II.

Ptolemy Ceraunus was the heir presumptive, but as Berenice's son grew older, a power struggle developed between the two half-brothers, which culminated in Ptolemy Ceraunus' departure from Egypt around 287 BC. Ptolemy II was formally elevated to the status of co-regent by Ptolemy I on 28 March 284 BC. Following his departure from Egypt, Ptolemy Ceraunus went to the court of Lysimachus, who ruled Macedon and western Asia Minor and who may have been his father-in-law. Lysimachus’ court was divided on the question of supporting Ceraunus. On the one hand, Lysimachus himself had been married to Ptolemy II's full sister, Arsinoe II, since 300 BC. On the other hand, Lysimachus' heir, was married to Ceraunus' full sister Lysandra; the two sisters were engaged in conflict over the succession, which Ceraunus' arrival exacerbated. Lysimachus chose to support Ptolemy II and sealed that decision at some point between 284 and 281 BC by marrying his daughter Arsinoe I to Ptolemy II. Continued conflict within Lysimachus' court led to the execution of Agathocles in 282 BC.

The course of events and Ptolemy Ceraunus' role in them is unclear. One historian, Ptolemy Ceraunus who carried out the murder of Agathocles. All other sources that mention Ceraunus place him on Agathocles' side in this dispute and report that he accompanied Agathocles' widow, his full-sister Lysandra, in her flight to the court of Seleucus I; the murder provoked a massive outcry from Lysimachus' subjects. Seeing an opportunity to intervene for his own gain, Seleucus invaded Lysimachus' kingdom early in 281 BC; this campaign culminated in the Battle of Corupedium, at which Lysimachus was killed and Seleucus annexed his kingdom to his empire. After the Battle of Corupedium, Ptolemy Ceraunus came into Seleucus' control. Seleucus took Ceraunus into his inner circle and planned to use him as a bargaining chip in the event of conflict with Ptolemaic Egypt. In September 281 BC, Seleucus prepared to invade Macedon, but as Seleucus was sacrificing at a place called Argos, Ptolemy Ceraunus murdered him, intending to seize control of the territories of his former protector.

Ceraunus was thus responsible for the death of the last surviving successor of Alexander the Great. After assassinating Seleucus, Ceraunus rushed to Lysimachia where he had himself acclaimed king by the portion of Seleucus' army, present there. At this time he formally relinquished his claim to the Egyptian throne. A series of gold staters and silver tetradrachms minted at Lysimachia appear to belong to this period, they have the same design as earlier coinage of Lysimachus: the head of Alexander the Great with the horn of Ammon on the obverse and a depiction of Athena seated, holding up a Nike on the reverse. The legend of the coins reads ΒΑΣΙΛΕΩΣ ΛΥΣΙΜΑΧΟΥ and the reverse includes two small symbols: a lion's head, the symbol of Lysimachus, a tiny elephant. Since the elephant was the symbol of Seleucus, these coins have sometimes been connected with the short period of Seleucus' rule over the region between the battle of Corupedium and his assassination. However, Hollstein has argued that these were coins of Ptolemy Ceraunus, intended to present him as the legitimate heir of Lysimachus and in possession of a formidable force of elephants.

The issue was small. Antigonos Gonatas, whose father Demetrius I Poliorcetes had been king of Macedon from 294-288 BC, attempted to seize control of Macedon, but Ptolemy Ceraunus defeated him in a naval battle and confined him to the city of Demetrias, Thessaly. A series of tetradrachms minted at Amphipolis, which feature a small Triton blowing a trumpet, have sometimes been associated with this victory, but this has been questioned, since they appear to have been minted a year after Ceraunus' death. Ptolemy Ceraunus made an alliance with Pyrrhus of Epirus, who had controlled the western portion of Macedon from 288-284 BC, ending the threat of attack from him; the alliance freed Pyrrhus to invade Italy to fight against the Roman Republic in the Pyrrhic War. Justin reports that Ceraunus provided Pyrrhus with a large number of troops: 5,000 infantry, 4,000 cavalry, 50 elephants, says that the alliance was sealed by the marriage of a daughter of Ceraunus to Pyrrhus; some scholars have been sceptical of this report, suggesting that Justin has confused Ptolemy Ceraunus with Ptolemy II, since they doubt that Ceraunus could have spared such a large number of troops at this moment.

The existence of the marriage is disputed. If the daughter did exist, her subsequent fa


.ie is the country code top-level domain which corresponds with the ISO 3166-1 alpha-2 code for the Republic of Ireland. The Internet Assigned Numbers Authority list the Computing Services Computer Centre of University College Dublin as its sponsoring organisation for domain. Since 2000 the business of administrating the domain registry has been handled by IE Domain Registry Limited. Domain name registration is open to individuals located in, or with a significant connection with, any part of the island of Ireland. In was a proposed new generic top-level domain for the global Irish was registered on 27 January 1988 and a year the registration domain names was delegated by Jon Postel to the Computing Services Computer Centre of University College Dublin headed by Dennis Jennings. In 2000, the administration of domain was sub-delegated by UCD to a new company, IE Domain Registry Limited. The Computing Services Computer Centre of University College Dublin remains the Internet Assigned Numbers Authority's sponsoring organisation for domain.

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