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

A biologic feature that is measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacological responses to a therapeutic intervention. For example, prostate specific antigen (PSA) is a biomarker for cancer of the prostate.

→ bio-; → marker.

1) A visible impression or trace on something, as a line, cut, dent, stain, or bruise (Dictionary.com).
2) To put a mark or marks on.

M.E., O.E. mearc, merc "boundary, sign, limit, mark" (cf. O.N. merki "boundary, sign," mörk "forest" (which often marked a frontier); O.Fr. merke, Goth. marka "boundary, frontier," Du. merk "mark, brand," Ger. Mark "boundary, boundary land"), from PIE *merg- "edge, boundary, border;" cf. Pers. marz, → frontier.

Dâj, variants dâq "brand, marking; hot," Hamedâni daj "in harvest, the sign placed on a wheat pile indicating not to be touched," dežan "acid, pungent;" Mid.Pers. dâq, dâk "hot," dažitan "to burn, scorch," dažišn "burning;" Av. dag-, daž- "to burn;" cf. Skt. dah- "to burn;" L. fovere "to warm, heat; " Arm. dažan "violent, wild;" Lith. degu "to burn;" O.E. fefor; E. fever. PIE base *dhegh- "to burn."

A blue star of visual magnitude 2.49, the brightest in the constellation → Pegasus. Markab is a relatively hot star of → spectral type B9, with a total luminosity about 200 times that of the Sun, a surface temperature of about 11,000 K, and a radius 4.3 times solar lying 140 light-years away.

Markab seems to be a corruption of Mankab in the original Ar. name of this star Mankib al-faras (منکب‌الفرس) "the horse's shoulder," from mankib "shoulder" + faras "horse," referring to Pegasus in Gk. mythology.

A galaxy with abnormally strong emission in the ultraviolet continuum and broad emission lines arising in a bright, semi-stellar nucleus.

Named after B. E. Markarian (1913-1985), an Armenian astronomer who made a catalog of such galaxies (1967-81); → galaxy.

A string of a dozen or so galaxies in the central region of the → Vigo cluster. The chain lies to the right of the cluster's dominant galaxy M87 and extends over nearly 2° on the sky. The chain's brightest galaxies are the lenticulars M84 and M86. At least seven galaxies in the chain appear to move coherently, although others appear to be superposed by chance.

→ Markarian; → chain.

Two → interacting galaxies, NGC 4438 and NGC 4435, located in → Markarian's chain of galaxies in the → Virgo cluster of galaxies. About 50 million → light-years away, the two galaxies are about 100,000 light-years apart. Gravitational → tidal forces from the → close encounter have ripped away at their stars, gas, and dust. The more massive NGC 4438 kept much of the material ripped out in the collision, while material from the smaller NGC 4435 was more easily lost.

→ Markarian galaxy; → eye.

1) An object used to indicate a position, place, or route.
2) A distinctive feature or characteristic indicative of a particular quality or condition.
3) Genetics: An allele used to identify a chromosome or to locate other genes on a genetic map (OxfordDictionaries.com).
4) → biomarker.

→ mark; → -er.

A → stochastic process, based on the classical → random walk concept, in which the probabilities of occurrence of various future states depend only on the previous state of the system and not on any of earlier states. Also called Markov process and Markovian principle.

Named after Andrey Andreyevich Markov (1856-1922), a Russian mathematician, who introduced this model in 1906; → chain.

A method for sampling from → probability distributions using → Markov chains. MCMC methods are widely used in data modeling for → Bayesian inference and numerical integration in physics, chemistry, biology, statistics, and computer science.

→ Markov chain; → Monte Carlo Method.

A → dwarf irregular galaxy that is a remote and rather isolated member of the → Local Group. Also known as DDO 221 and LEDA 143. It is a dim galaxy located in the constellation → Cetus, about three million → light-years from the → Milky Way. Its nearest neighbor, the → dwarf galaxy IC 1613, is one million light-years away. Quite elongated, with a largest extension of more than 8,000 light-years, WLM is about 12 times smaller than the Milky Way, a measurement that includes a → halo of extremely → old stars. WLM has a → metallicity only about one-tenth that of the Milky Way.

Named after astronomer Max Wolf (1863-1932), who discovered the galaxy in 1909, and astronomers Knut Lundmark (1889-1958) and Philibert Jacques Melotte (1880-1961), who identified it as a galaxy some fifteen years later.