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Astrophysical Journal Letters
''The Astrophysical Journal'' (''ApJ'') 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, in January 2009, publication was transferred to IOP Publishi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethan Vishniac
Ethan Tecumseh Vishniac (born 1955) is an American astrophysicist. He is the Editor-in-Chief of the Astrophysical Journal and a professor of Astronomy at Johns Hopkins University in Baltimore, after holding positions at University of Saskatchewan in Saskatoon, McMaster University in Hamilton, Ontario, Canada, and University of Texas in Austin. Education Vishniac graduated from University of Rochester and Harvard University. He received his Ph.D. in astrophysics in 1980 from Harvard University while working under the direction of William H. Press. After Harvard, Vishniac spent two years as a post doctoral fellow working under Jeremiah P. Ostriker at Princeton University. Research His best known scientific work is the study of instabilities in expanding blast waves. In Vishniac (1983), he demonstrated that a blast wave expanding in a sufficiently compressible medium would be subject to a linear overstability growing as the square root of time. This is usually known as the Vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James E
James may refer to: People * James (given name) * James (surname) * James (musician), aka Faruq Mahfuz Anam James, (born 1964), Bollywood musician * James, brother of Jesus * King James (other), various kings named James * Prince James (other) * Saint James (other) Places Canada * James Bay, a large body of water * James, Ontario United Kingdom * James College, a college of the University of York United States * James, Georgia, an unincorporated community * James, Iowa, an unincorporated community * James City, North Carolina * James City County, Virginia ** James City (Virginia Company) ** James City Shire * James City, Pennsylvania * St. James City, Florida Film and television * ''James'' (2005 film), a Bollywood film * ''James'' (2008 film), an Irish short film * ''James'' (2022 film), an Indian Kannada-language film * "James", a television episode of ''Adventure Time'' Music * James (band), a band from Manchester ** ''James ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absorption (electromagnetic Radiation)
In physics, absorption of electromagnetic radiation is how matter (typically electrons bound in atoms) takes up a photon's energy—and so transforms electromagnetic energy into internal energy of the absorber (for example, thermal energy). A notable effect of the absorption of electromagnetic radiation is attenuation of the radiation; attenuation is the gradual reduction of the intensity of light waves as they propagate through a medium. Although the absorption of waves does not usually depend on their intensity (linear absorption), in certain conditions (optics) the medium's transparency changes by a factor that varies as a function of wave intensity, and saturable absorption (or nonlinear absorption) occurs. Quantifying absorption Many approaches can potentially quantify radiation absorption, with key examples following. * The absorption coefficient along with some closely related derived quantities * The attenuation coefficient (NB used infrequently with meaning ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Radiation
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength, ranging from radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. All forms of EMR travel at the speed of light in a vacuum and exhibit wave–particle duality, behaving both as waves and as discrete particles called photons. Electromagnetic radiation is produced by accelerating charged particles such as from the Sun and other celestial bodies or artificially generated for various applications. Its interaction with matter depends on wavelength, influencing its uses in communication, medicine, industry, and scientific research. Radio waves enable broadcasting and wireless communication, infrared is used in thermal imaging, visible light is essential for vision, and higher-energy radiation, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectrum
A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism. In the optical spectrum, light wavelength is viewed as continuous, and spectral colors are seen to blend into one another smoothly when organized in order of their corresponding wavelengths. As scientific understanding of light advanced, the term came to apply to the entire electromagnetic spectrum, including radiation not visible to the human eye. ''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 bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wavelength
In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves), phase'' on the wave, such as two adjacent crests, troughs, or zero crossings. Wavelength is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The multiplicative inverse, inverse of the wavelength is called the ''spatial frequency''. Wavelength is commonly designated by the Greek letter lambda (''λ''). For a modulated wave, ''wavelength'' may refer to the carrier wavelength of the signal. The term ''wavelength'' may also apply to the repeating envelope (mathematics), envelope of modulated waves or waves formed by Interference (wave propagation), interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed phase velocity, wave speed, wavelength is inversely proportion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 irradiance of the light but could also, for instance, be the polarization state. The independent variable is usually the wavelength of the light or a closely derived physical quantity, such as the corresponding wavenumber or the photon energy, in units of measurement such as centimeters, reciprocal centimeters, or electron volts, respectively. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Augustus Young
Charles Augustus Young (December 15, 1834 – January 4, 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, 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 Case Western Reserve University, 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 Ohio Infantry, 85th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward C
Edward is an English male name. It is derived from the Anglo-Saxon name ''Ēadweard'', composed of the elements '' ēad'' "wealth, fortunate; 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 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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''. Etymology The name's etymology is a Common Germanic noun ''*karilaz'' meaning "free man", which survives in English as wikt:churl, churl (< Old English ''ċeorl''), which developed its deprecating sense in the Middle English period. Some Germanic languages, for example Dutch language, Dutch and German ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, Ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
