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

An → adaptive optics instrument used on the → European Southern Observatory (ESO) 3.6-m telescope at La Silla. It was an upgraded version of COME-ON-PLUS, the → Very Large Telescope (VLT) adaptive optics prototype. It had 52 → actuators and performed corrections of the mirror 200 times per second. The reference → wavefront was sensed in the → visible. The observation was done in the → near-infrared (1-5 μm).

→ adaptive; → optics; → near-infrared; → system.

The high redshift of a quasar which is seemingly physically associated with a galaxy of low redshift.

→ anomalous; → redshift.

A family of strong infrared emission bands at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 μm which are widely observed in a large variety of objects, such as → H II regions, → reflection nebulae, → planetary nebulae, and the → diffuse interstellar medium of our galaxy and other galaxies. Solar system objects, such as carbonaceous → meteorites and → interplanetary dust particles are also known to display these features. They are suggested to be due to → polycyclic aromatic hydrocarbons.

→ aromatic; → infrared; → band.

The light that has undergone → backscattering.

→ backscatter; → backscattering.

Having a bar like structure.

→ bar.

A transitional class of object between the classic spiral galaxies and true irregular systems. The → Large Magellanic Cloud, the nearest and best studied example of the class, is, contrary to popular opinion, not an irregular galaxy. The LMC and other members of the SBm class have definite structural signatures. They are generally dominated by a pronounced asymmetric bar -- one that is offset from the optical center of the galaxy -- with a nascent spiral arm emanating from one end. As is the case with irregular galaxies, the optical centers of SBm type systems are not particularly special places. Disk systems later than Sc characteristically lack a central stellar concentration in addition to having weak spiral structure; this is true of SBm-type galaxies. SBm galaxies are typically very active in their star formation activity, often containing a large star-forming complex situated at one end of the bar. Beyond these general trends there is a tremendous amount of dispersion in physical properties within the SBm class, particularly in the strength of the spiral structure. At one extreme are the "one-armed" spirals such as NGC 3664 and NGC 4027 which are dominated by single, looping spiral arm. On the other hand NGC 4861 shows little evidence of spiral structure and it is dominated by a large star-forming complex at one end of its bar. The class smoothly leads to the Barred Magellanic irregulars (IBm) which show no indication of spiral structure (Wilcots et al. 1996, AJ 111, 1575).

→ Magellanic; → spiral; → galaxy.

A → spiral galaxy that exhibits a bar-shaped structure in its nucleus. → galactic bar.

→ barred; → spiral; → galaxy.

An image which is dim, indistinct, or vague in appearance, for instance when the optics is not well-focused or when the seeing is poor. The same as → unsharp image, contrary to → sharp image.

Blurred, p.p. of → blur; → image.

A diffuse radiation which consists of the cumulative infrared emission from all galaxies throughout cosmic history. It is about 50 times weaker than the → cosmic microwave background radiation (CMBR). Since the CIB is produced by the dust within such galaxies, it carries a wealth of information about the processes of star formation therein.

→ cosmic; → infrared; → background.

The → redshift of a remote object (galaxy, quasar, supenova) due to the expansion of the Universe.

→ cosmological; → redshift.

1a) Commendation or honor given for some action, quality, etc.
1b) A source of pride or honor.
1c) The ascription or acknowledgment of something as due or properly attributable to a person, institution, etc.
1d) Influence or authority resulting from the confidence of others or from one's reputation.
1e) A sum of money due to a person; anything valuable standing on the credit side of an account:
2) To believe; put confidence in; trust; have faith in (Dictionary.com).

M.E., from M.Fr. crédit "belief, trust," from It. credito, from L. creditum "a loan, thing entrusted to another," from p.p. of credere "to trust, entrust, believe."

Arjé, from arj "esteem, honor, dignity; price, worth, value," variant of arz "price, value," arzidan "to be worth;" Mid.Pers. arz- "to be worth;" Av. arj- "to be worth," arəjaiti "it is worth;" Proto-Ir. *Harj- "to be worth;" cf. Skt. arh- "to earn, be worth;" Gk. alphein "to earn, to obtain;" Lith. alga "salary, pay." "to be woth." Arjé dâdan with dâdan "to give, grant, yield," → datum.

The process of converting crude observational data into usable information for scientific interpretation, by correcting, rearranging, ordering, and simplifying.

→ data; → reduction.

To correct the intensity or flux of a spectral line by eliminating the → reddening effect of → interstellar dust.

De-redden, from → de- + redden verb of → red.

Vâsorxidan, from vâ-, → de-, + sorxidan verb of sorx, → red.

A magnitude which has been corrected for the interstellar reddening.

De-reddened, p.p. of → de-redden; → magnitude.

Borz, → magnitude; vâsorxidé p.p. of vâsorxidan, → de-redden.

The process that de-reddens. The state of being de-reddened.

Verbal noun of → de-redden.

In a CCD detector, phenomenon caused by charge traps or potential pockets, which prevent electrons from being released to the adjacent pixel; eventually the electrons may be released in a subsequent cycle.

Differed, p.p. of differ, from O.Fr. différer, from L. differre "set apart, put off, delay," also "be different, differ," → differ; → charge.

Bâr→ charge; bâzdâšté "prevented," p.p. of bâzdâštan, from preventive suffix bâz- + dâštan "to hold, have, maintain," Mid.Pers. dâštan, O.Pers./Av. root dar- "to hold, keep back, maitain, keep in mind," Skt. dhar- "to hold, keep, preserve," dharma- "law," Gk. thronos "elevated seat, throne," L. firmus "firm, stable," Lith. daryti "to make," PIE *dher- "to hold, support."

An act of attacking or plundering.

→ de-; → predation.

Lacking → order.

→ disorder + -ed.

Birâyé, from bi- "without," → a-, + râyé, → order.

A process by which the nucleosynthesis products inside a star are drawn to upper layers of the star. → first dredge-up; → second dredge-up; → third dredge-up.

From M.E. (Scots) dreg-, O.E. draeg- (in drægnet "dragnet"), akin to dragan "to draw" + up.

Birunkašid, past stem of birun kašidan, from birun "out, the outside" (Mid.Pers. bêron, from bê "outside, out, away" + rôn "side, direction," Av. ravan- "(course of a) river") + kašidan "to draw," Mid.Pers. kašitan, Av. karš- "to draw," Skt. kars-, kársati "to pull, drag, plough," Gk. pelo, pelomai "to be busy, to bustle."

A portion of the far infrared radiation, including wavelengths between 100 and 1,000 microns.

→ extreme; → infrared.