Astrophysical Journal Letters
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Astrophysical Journal Letters
''The Astrophysical Journal'', often abbreviated ''ApJ'' (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler. The journal discontinued its print edition and became an electronic-only journal in 2015. Since 1953 ''The Astrophysical Journal Supplement Series'' (''ApJS'') has been published in conjunction with ''The Astrophysical Journal'', with generally longer articles to supplement the material in the journal. It publishes six volumes per year, with two 280-page issues per volume. ''The Astrophysical Journal Letters'' (''ApJL''), established in 1967 by Subrahmanyan Chandrasekhar as Part 2 of ''The Astrophysical Journal'', is now a separate journal focusing on the rapid publication of high-impact astronomical research. The three journals were published by the University of Chicago Press for the American Astronomical Society until, ...
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The Astrophysical Journal Logo
''The'' () is a grammatical Article (grammar), article in English language, English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the Most common words in English, most frequently used word in the English language; studies and analyses of texts have found it to account for seven percent of all printed English-language words. It is derived from gendered articles in Old English which combined in Middle English and now has a single form used with pronouns of any gender. The word can be used with both singular and plural nouns, and with a noun that starts with any letter. This is different from many other languages, which have different forms of the definite article for different genders or numbers. Pronunciation In most dialects, "the" is pronounced as (with the voiced dental fricative followed by a schwa) when followed by a consonant s ...
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CC-BY
A Creative Commons (CC) license is one of several public copyright licenses that enable the free distribution of an otherwise copyrighted "work".A "work" is any creative material made by a person. A painting, a graphic, a book, a song/lyrics to a song, or a photograph of almost anything are all examples of "works". A CC license is used when an author wants to give other people the right to share, use, and build upon a work that the author has created. CC provides an author flexibility (for example, they might choose to allow only non-commercial uses of a given work) and protects the people who use or redistribute an author's work from concerns of copyright infringement as long as they abide by the conditions that are specified in the license by which the author distributes the work. There are several types of Creative Commons licenses. Each license differs by several combinations that condition the terms of distribution. They were initially released on December 16, 2002, by ...
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Electromagnetic Radiation
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic field, electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, Light, (visible) light, ultraviolet, X-rays, and gamma rays. All of these waves form part of the electromagnetic spectrum. Classical electromagnetism, Classically, electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric field, electric and magnetic fields. Depending on the frequency of oscillation, different wavelengths of electromagnetic spectrum are produced. In a vacuum, electromagnetic waves travel at the speed of light, commonly denoted ''c''. In homogeneous, isotropic media, the oscillations of the two fields are perpendicular to each other and perpendicular to the direction of energy and wave propagation, forming a transverse wave. The position of an electromagnetic wave w ...
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Spectrum
A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism. As scientific understanding of light advanced, it came to apply to the entire electromagnetic spectrum. It thereby became a mapping of a range of magnitudes (wavelengths) to a range of qualities, which are the perceived "colors of the rainbow" and other properties which correspond to wavelengths that lie outside of the visible light spectrum. Spectrum has since been applied by analogy to topics outside optics. Thus, one might talk about the " spectrum of political opinion", or the "spectrum of activity" of a drug, or the "autism spectrum". In these uses, values within a spectrum may not be associated with precisely quantifiable numbers or definitions. Such uses imply a broad range of condition ...
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Wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The inverse of the wavelength is called the spatial frequency. Wavelength is commonly designated by the Greek letter ''lambda'' (λ). The term ''wavelength'' is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths. Wavelength depends on the medium (for example, vacuum, air, or water) that a wav ...
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Spectroscope
An optical spectrometer (spectrophotometer, spectrograph or spectroscope) is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization state. The independent variable is usually the wavelength of the light or a unit directly proportional to the photon energy, such as reciprocal centimeters or electron volts, which has a reciprocal relationship to wavelength. A spectrometer is used in spectroscopy for producing spectral lines and measuring their wavelengths and intensities. Spectrometers may operate over a wide range of non-optical wavelengths, from gamma rays and X-rays into the far infrared. If the instrument is designed to measure the spectrum on an absolute scale rather than a relative one, then it is typically called a spectrophotometer. The majority o ...
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Charles Augustus Young
Charles Augustus Young (15 December 1834 – 4 January 1908) one of the foremost solar spectroscopist astronomers in the United States. He observed solar eclipses and worked on spectroscopy of the Sun. He observed a solar flare with a spectroscope on 3 August 1872, and also noted that it coincided with a magnetic storm on Earth. Young graduated from Dartmouth College in 1853. For two years, he taught classes at Phillips Academy in Andover, Massachusetts. The following year, he studied at the theological seminary in Andover, while also continuing to teach. In 1857, he became the Professor of Mathematics and Natural Philosophy at Western Reserve College, now known as Case Western Reserve University, devoting nine years. Young's name is inscribed on the Loomis Observatory, which is the oldest observatory in the United States still remaining in its original location. In 1862, he served in the 85th Regiment of Ohio during the Civil War. He was elected as a member to the Amer ...
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Edward C
Edward is an English given name. It is derived from the Anglo-Saxon name ''Ēadweard'', composed of the elements '' ēad'' "wealth, fortune; prosperous" and '' weard'' "guardian, protector”. History The name Edward was very popular in Anglo-Saxon England, but the rule of the Norman and Plantagenet dynasties had effectively ended its use amongst the upper classes. The popularity of the name was revived when Henry III named his firstborn son, the future Edward I, as part of his efforts to promote a cult around Edward the Confessor, for whom Henry had a deep admiration. Variant forms The name has been adopted in the Iberian peninsula since the 15th century, due to Edward, King of Portugal, whose mother was English. The Spanish/Portuguese forms of the name are Eduardo and Duarte. Other variant forms include French Édouard, Italian Edoardo and Odoardo, German, Dutch, Czech and Romanian Eduard and Scandinavian Edvard. Short forms include Ed, Eddy, Eddie, Ted, Teddy and Ned. ...
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Charles S
Charles is a masculine given name predominantly found in English language, English and French language, French speaking countries. It is from the French form ''Charles'' of the Proto-Germanic, Proto-Germanic name (in runic alphabet) or ''*karilaz'' (in Latin alphabet), whose meaning was "free man". The Old English descendant of this word was ''Churl, Ċearl'' or ''Ċeorl'', as the name of King Cearl of Mercia, that disappeared after the Norman conquest of England. The name was notably borne by Charlemagne (Charles the Great), and was at the time Latinisation of names, Latinized as ''Karolus'' (as in ''Vita Karoli Magni''), later also as ''Carolus (other), Carolus''. Some Germanic languages, for example Dutch language, Dutch and German language, German, have retained the word in two separate senses. In the particular case of Dutch, ''Karel'' refers to the given name, whereas the noun ''kerel'' means "a bloke, fellow, man". Etymology The name's etymology is a Common ...
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Hermann Carl Vogel
Hermann Carl Vogel (; ; 3 April 1841 – 13 August 1907) was a German astrophysicist. He was born in Leipzig, Kingdom of Saxony. From 1882 to 1907 he was director of the Astrophysical Observatory, Potsdam. He made extensive discoveries using spectral analysis of the stars. Life Vogel was born in 1841 in Leipzig. His father was director of the united Bürgerschulen and founder of the Realschule in Leipzig. His siblings included Eduard Vogel (1829–1856), Africa explorer and astronomer; Elise Polko (1823–1899), poet and singer and Julie Dohmke (1827–1913), writer, publisher, translator. In 1862, Vogel began his studies at the Polytechnikum in Dresden and in 1863 went to University of Leipzig. In Leipzig he was assistant to Karl Christian Bruhns and took part in measurements of double stars carried out by Friedrich Wilhelm Rudolf Engelmann. Vogel was awarded a doctorate in 1870 from Jena for work on nebulae and star clusters and went in the same year to the S ...
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Pietro Tacchini
Pietro Tacchini (March 21, 1838 – March 24, 1905) was an Italian astronomer. He was born and raised in Modena, Italy. He studied engineering at the University of Padova. At the age of 21, he was appointed the director of a small observatory in Modena. By 1863 he became the ''Primo Astronomo Aggiunto'', or director of the observatory, at Palermo, Italy. He remained there until 1879, and focused most of his attention on observations of the Sun. In 1865 he founded the specialist physical astronomy journal, ''Memorie della Società degli Spettroscopisti'', and remained the editor until 1905. (This publication later became the ''Memorie della Società Astronomica Italiana'' in 1920.) Tacchini established an observation network with other Italian astronomers to spectroscopically examine the sun at about the same time daily. He likewise organized an observatory in Calcutta to watch the sun when conditions were unfavorable in Italy. In 1874 he led an expedition to Muddapur, India ...
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William Huggins
Sir William Huggins (7 February 1824 – 12 May 1910) was an English astronomer best known for his pioneering work in astronomical spectroscopy together with his wife, Margaret. Biography William Huggins was born at Cornhill, Middlesex, in 1824. In 1875, he married Margaret Lindsay, daughter of John Murray of Dublin, who also had an interest in astronomy and scientific research. She encouraged her husband's photography and helped to put their research on a systematic footing. Huggins built a private observatory at 90 Upper Tulse Hill, London, from where he and his wife carried out extensive observations of the spectral emission lines and absorption lines of various celestial objects. On 29 August 1864, Huggins was the first to take the spectrum of a planetary nebula when he analysed NGC 6543. He was also the first to distinguish between nebulae and galaxies by showing that some (like the Orion Nebula) had pure emission spectra characteristic of gas, while others ...
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