An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

In → gamma ray → spectroscopy, a technique to reduce the contribution of gamma rays generated by → Compton scattering.

→ Compton; → suppression.

1a) Relating to a particular instance or object, as opposed to → general.
1b) Relating to or characteristic of things capable of being perceived by the senses, as opposed to → abstractions.
1c) Formed by the coalescence of particles; condensed; solid.
2a) To form into a mass by coalescence of particles; render solid. → concretion.
2b) To make real, tangible, or particular.

M.E. concret, from L. concretus "condensed, hardened, thick, stiff, clotted," p.p. of concrescere "to grow together," from → com- "together" + crescere "to grow," cognate with Pers. korré "foal, colt," korr "son, boy," → crescent.

Ambas, a variant of anbast in several dialects (e.g. Tabari) "dense, thick;" Mid.Pers. hambast "compact, tied together," from ham- "together," → com- + bast p.p. of bastan "to clot, congeal; to bind," Av./O.Pers. band- "to bind, fetter," basta- "bound, tied," Skt. bandh- "to bind, tie, fasten," PIE *bhendh- "to bind," cf. Ger. binden, E. bind.
Basudani "tangible," from basudan "to touch," variant pasâvidan, ultimately from Proto-Ir. *pra-sau-, from *sau- "to rub; whet; wear;" cf. sudan, sâyidan "to rub," sân "whetstone," variants fasân, afsân, awsân; Mid.Pers. sūdan "to rub;" Khotanese sauy- "to rub;" Sogd. ps'w "to rub;" Choresmian bs'w "to rub off, polish;" Skt. sā- "to sharpen, whet."

1) The act or process of concreting or becoming substantial.
2) The state of being concreted.
3) Geology: A hard, dense mass of mineral matter that formed within a rock of a composition different from its own through the precipitation of minerals and ranging in diameter from centimeters to meters.

Verbal noun of → concrete.

The act of concurring; accordance in opinion; agreement.

Verbal noun of → concur.

1) Existing, happening, or done at the same time.
2) Acting in conjunction; cooperating. → concurrent forces.

Verbal adj. from → concur.

A system of forces applied to a → rigid body in such manner that their lines of action intersect at a single point. A system of concurrent forces acting on a rigid body can be replaced by an equivalent force applied at the same point. → line of action.

→ concurrent; → force.

1a) The formation or expression of an opinion or theory without sufficient evidence for proof. → mathematical conjecture.
1b) An opinion or theory so formed or expressed; → guess; → speculation.
2) To conclude or suppose from grounds or evidence insufficient to ensure reliability (Dictionary.com).

An opinion or theory formed without sufficient evidence for proof; guess; speculation.

M.E., from O.Fr. conjecture "surmise, guess," or directly from L. coniectura "conclusion, interpretation, guess, inference," literally "a casting together (of facts, etc.)," from coniectus, p.p. of conicere "to throw together," from → com- "together" + iacere "to throw," → eject.

Hâšan, from hâ-, variant ham-, → com-, + šan, from ešândan "to throw out," → eject.

An → interference process in which the → amplitude of the resultant wave is greater than that of either individual waves. See also → destructive interference.

Constructive, from M.Fr. constructif or from M.L. constructivus, from L. construct-, p.p. stem of construere "to heap up," from → con- + struc- variant stem of struere "to build," → structure; → interference.

Andarzaneš, → interference; sâzandé "constructive," from sâxtan, → structure.

The central region of a → massive star where → convection prevails due to steep gradient of temperature relative to pressure.

→ convective; → core.

A theorem stating that the → Fourier transform of the convolution of f(x) and g(x) is equal to the product of the Fourier transform of f(x) and g(x): F{f*g} = F{f}.F{g}.

→ convolution; → theorem.

A general heading which covers a wide variety of complex views on → quantum theory. As the first and the founding interpretation of the → quantum mechanics, it was developed in the late 1920's mainly by the Danish physicist Niels Bohr, but also Werner Heisenberg, Max Born and other physicists who made important contributions to the overall understanding of this field. Bohr expressed himself on the subject at various meetings and later published several articles and comments, but he never wrote a systematic and complete version of his views. There is not a unique Copenhagen Interpretation but various more or less complete versions, the common denominator of which is mainly the work of Bohr. Among those opposed to the Copenhagen Interpretation have been Albert Einstein, Erwin Schrödinger, Louis de Broglie, Max Planck, David Bohm, Alfred Landé, Karl Popper, and Bertrand Russell. The Copenhagen Interpretation recognizes that the deterministic picture of the universe that works so well at the macroscopic level does not work for the world at the quantum level. The universe at the quantum level is predictable only in a statistical sense. This implies that we can never really know the nature of quantum phenomena. The four cornerstones of the Copenhagen Interpretation are: → wave-particle duality, the probability → wave function, the → uncertainty principle, and the significance of the → observer. The observer is of the utmost importance because he causes the reality to unfold in the way it does. The key feature of the Copenhagen Interpretation is a concept known as the → collapse of the wave function, for which there is no known physical explanation; see also → Schrodinger's cat.

Copenhagen, from Dan. København "merchant's port," from køber "merchant" ("buyer") + havn "port," from the fact that the originator and chief interpreter of this school was Niels Bohr whose headquarters was in Copenhagen; → interpretation.

1) The central region of a star in which energy is generated by → thermonuclear reactions.
2) The central region of a planet or satellite which has a → differentiated interior.
3) The innermost and densest layer of the Earth, lying from 2890 km to 6360 km beneath the surface. It consists primarily of the metals iron and nickel, and is divided into the → outer core, which is believed to be liquid, and the → inner core, which is believed to be solid.
4) The central region of a → star cluster.
5) A flat → density profile representing the distribution of stars in the central region of a galaxy. Cores are found in high mass galaxies. They are believed to result from the interaction of a central → supermassive black hole with another merging black hole.
6) A progenitor of → protostars. → dense core.
7) → reactor core.

Probably from O.Fr. cœur "core of fruit," literally "heart," from L. cor "heart," cf. Gk. kardia: P.Gmc. *khertan- (O.E. heorte, E. heart, Ger. Herz, Bret. kreiz "middle"), Skt. hrd-; Av. zərəd-; Mid.Pers. dil; Mod.Pers. del; Baluci zird; Arm. sirt; PIE base *kerd- "heart".

Maqzé, from maqz "kernel; brain; marrow" + nuance suffix -é. Mod.Pers. maqz from Mid.Pers. mazg "brain; marrow," Av. mazga- "marrow; brain" cf. Skt. majján- "marrow," P.Gmc. *mazga-, O.E. mearg "marrow," Lith. smagenes "brain," O.H.G. mark "marrow," PIE base *mozgho- "marrow, brain".

The collapse of a → massive star's core at the → final → stages of its → evolution when the core consists entirely of → iron (→ iron core). Since iron cannot burn in → nuclear reaction, no energy is generated to support the → gravitational collapse. The result will be a → supernova explosion of → Type Ib, → Type Ic, or → Type II. See also → core-collapse supernova.

→ core; → collapse.

An → elliptical galaxy that displays a → surface brightness profile with a distinct break from a steep outer slope to a shallower inner → cusp. Core profiles mainly occur in very luminous elliptical galaxies and are considered the result of dissipation-less → mergers of two galaxies that have central → supermassive black holes (S. P. Rusli et al., 2013, AJ 146, 160).

→ core; → elliptical; → galaxy.

The mass distribution of → pre-stellar cores in → star-forming regions. The CMF is usually represented by dN/dM = M^α, where dM is the mass interval, dN the number of cores in that interval, and α takes different values in different mass ranges. In the case of → low-mass stars, it is found that the CMF resembles the → Salpeter function, although deriving the masses and radii of pre-stellar cores is not straightforward. The observational similarity between the CMF and the → initial mass function (IMF) was first put forth by Motte et al. (1988, A&A, 336, 150), and since then many other samples of dense cores have been presented in this context. For example, Nutter & Ward-Thompson (2007, MNRAS 374, 1413), using SCUBA archive data of the Orion star-forming regions, showed that the CMF can be fitted to a three-part → power law consistent with the form of the stellar IMF. Recent results, obtained using observations by the → Herschel Satellite, confirm the similarity between the CMF and IMF with better statistics (Könyves et al. 2010, A&A, 518, L106; André et al. 2010, A&A, 518, L102). Moreover, these works show that the CMF has a → lognormal distribution (i.e. dN/dlog M follows a → Gaussian form against log M), as is the case for the IMF at low masses (below about 1 solar mass).

→ core; → mass; → function.

→ convective overshooting.

→ core; → overshooting.

A → profile representing the number density of stars in the → core of a galaxy.

→ core; → profile.

A supernova arising from the → core collapse of a → massive star. Same as → Type Ib, → Type Ic, or → Type II supernova.

→ core; → collapse; → supernova.

A → radio-loud quasar in which the central source is enhanced by → relativistic beaming and characterized by a → flat  → spectrum. It has been conjectured that this phenomenon is an → orientation effect. If a radio-loud quasar is seen along its → jet, it will appear as a core-dominated source. See also → lobe-dominated quasar.

→ core; → dominate; → quasar.

A radio galaxy characterized by an emission "halo" surrounding a more intense "core". About 20% of the known extended radio sources are of the core-halo type.

→ core; → halo; → galaxy.