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

Short for → Wolf-Rayet.

→ Wolf-Rayet star.

Short for → Wolf-Rayet star.

→ Wolf-Rayet star.

The most luminous → galaxy known. It has a → redshift of z = 4.601 and a → bolometric luminosity of 3.5 × 10¹⁴Lsun. W2246-0526 hosts a deeply buried → active galactic nucleus (AGN)/→ supermassive black hole (SMBH). Discovered using the → Wide-field Infrared Survey Explorer (WISE), W2246-0526 is classified as a → hot dust-obscured galaxy, based on its → luminosity and → dust temperature (T. Diaz-Santos et al. 2015, arXiv:1511.04079).

Object designation from → Wide-field Infrared Survey Explorer (WISE).

To walk through water, snow, sand, or any other substance that impedes free motion or offers resistance to movement (Dictionary.com).

M.E. waden "to go, wade;" O.E. wadan "to go;" cf. Dan. vade, O.Fris. wada, Du. waden, Ger. waten, O.Norse vatha; akin to O.E. wæd "ford, sea," L. vadere "to go, rush," vadum "shoal, ford."

Gampidan, related to Proto-Ir. *gamp-, *gamb- "to move," cf. Dezfuli gomba, Bardesiri gopak "jump with two feet;" Sogd. (+ *â-) âγamp "walking;" (+ *uz-) Yighda žib-/žibi- "to rise, to stand," jib- "to awake;" (+ *ham-) Wakhi gəfs-/gəfst- "to run."

1) The track left by a moving ship.
2) A turbulent region appearing behind an object in a fluid which streams around the object, for example behind an aircraft in flight.

Cognate with M.L.G. wake "wake," Nor. dialect vok, O.N. vok, voka "hole in the ice."

Kel, from Tabari kel, kal "trail, track, footprint."

1) To move along on foot at a moderate pace; advance by steps.
2a) An act or instance of walking.
2b) Physics: A moving of a particle among particles. → random walk; → quantum walk.

M.E. walken, from O.E. wealcan "to toss, roll;" cf. O.N. valka "to drag about," Dan. valke "to full," M.Du. walken "to knead, press, full," O.H.G. walchan "to knead," Ger. walken "to full."

Camidan "to walk (proudly)," variant gâmidan "to walk," gâm "step, pace" (related to âmadan "to come," → consequence); Mid.Pers. gâm "step, stride, pace;" O.Pers. gam- "to come; to go;" Av. gam- "to come; to go," jamaiti "goes;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE stem *g^wem- "to go, come."
Puyeš, verbal noun of puyidan "to walk, run, trot; wander," from Mid.Pers. pôy-, pwd- "to run;" cf. Gk. speudein "to hasten;" Lith. spudinti.

1) An upright continuous structure that divides one area from another or surrounds an area.
2) A wall-like, enclosing part, mass, or thing .

M.E., from O.E. w(e)all "rampart, dike, cliff," also "defensive fortification around a city, side of a building" (O.Sax., O.Fris., M.L., M.Du. wal), from L. vallum "wall, rampart."

Divâr "wall," from Mid.Pers. dîvâr "wall;" related to Mid.Pers. bâr, var "enclosure, defences, fortress;" Mod.Pers. bâru "wall, rampart, fortification; fort; tower;" O.Pers. didā- "wall, stronghold, fortress;" Av. var- "castle," from var- "to cover, conceil;" Proto-Iranian *dida-vāra-; cf. Skt. dehī- "wall;" Gk. teikhos "wall;" E. dike, ditch.

A photometric system with five wavelength ranges that does not use filters. Instead it uses prisms and lenses (spectroscopy) to select the bands simultaneously. The wavelengths and the bandwidths are: W, 3250 and 140 Å; U, 3630 and 240 Å; L, 3840 and 230 Å; B, 4320 and 450 Å; and V, 5470 and 720 Å. The Walraven photometer was unique in design and remained literally unique as copies were never built. In addition, during its whole life the photometer was mounted permanently on the same telescope that had been built specifically for this instrument, the 91 cm Lightcollector' reflector, which started in 1958 at the Leiden Southern Station in Broederstroom, South-Africa. After 20 years in South-Africa the telescope and photometer were moved to the European Southern Observatory La Silla observatory in Chile. The photometric observations were resumed in March 1979 and continued for another 12 years until the decommissioning of the photometer in 1991.

After the inventors, the Dutch astronomer Theodore Walraven (1916-) and his wife Johanna Helena Walraven, née Terlinden (1920-89); → photometry.

Decreasing in strength, intensity, power, etc.

Waning, from wane, from M.E. wanen (v.), O.E. wanian "to lessen;" cf. O.S. wanon, O.N. vana, O.Fris. wania, M.Du. waenen, O.H.G. wanon "to wane, to grow less."

Kâhandé "waning, decreasing;" from kâstan, kâhidan "to decrease;" Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen;" Av. kasu- "small, little" (Mod.Pers. keh); Proto-Iranian *kas- "to be small, diminish, lessen."

The crescent phase of the Moon following the → last quarter which finally disappears with setting Sun.

→ waning; → crescent.

The oval shape of the moon a few days after the → full moon and before the → last quarter.

→ waning; → gibbous.

The circumstance when the phase of the Moon is decreasing from → full moon to → new moon.

→ waning; → moon.

A state of armed conflict between states, or between groups within states.

From M.E. werre, from O.E. werre, wyrre, from Old Northern Fr. werre, akin to O.H.G. werra "confusion, strife, quarrel," Du. war "confusion, disarray," O.E. wyrsa, wiersa "worse," O.Norse verri "worse; confounded;" ultimately from PIE *wers- "to confuse, mix up."

Jang, from Mid.Pers. jang "struggle, battle, fight."

Moderately hot.

M.E.; O.E. wearm (cf. O.S., O.Fris., M.Du., O.H.G., Ger. warm, O.N. varmr, Goth. warmjan "to warm"); cognate with Pers. garm, as below.

Garm "warm;" Mid.Pers. garm "warm;" O.Pers. garma-pada "name of the fourth month" (June-July); Av. garəma- "warm; heat;" cf. Skt. gharmá "heat;" Gk. therme, thermos; L. formus "warm;" E. warm, as above; PIE base *ghworm-/*ghwerm- "warm."

A cloud of ionized gas within → active galactic nuclei (AGN) that causes absorption at → soft X-ray wavelengths. Warm absorbers were first suggested by Halpern (1984) to explain Einstein data of the quasar MR 2251-178. They are dubbed "warm" absorbers as they imply gas at temperatures of 10⁴-10⁵ K; the gas is → photoionized, not collisionally ionized. High resolution observations of warm absorbers have shown that they are outfowing. See also → cold absorber (Ceri Ellen Ashton, 2005, A Study of Warm Absorbers in Active Galactic Nuclei, Thesis, Mullard Space Science Laboratory Department of Space and Climate Physics University College London ).

→ warm; → absorber.

Meteo.: A leading edge that advances in a mass of air and replaces cooler air by warm air.

→ warm; → front.

A component of the → interstellar medium consisting of an extremely tenuous (density 0.1 to 10 cm^-3) and relatively warm gas (temperature about 8,000 K) filling the space between denser neutral and ionized gas. Hydrogen is partly ionized, partly atomic and observed by the → 21-centimeter line in emission.

→ warm; → intercloud medium.

The space containing a cluster of galaxies filled with a tenuous gas of temperature 10⁵ to 10⁷ K and density 10^-6 to 10^-4 cm^-3. WHIM has been continuously shock-heated during the process of structure formation. It is so highly ionized that it can only absorb or emit far-ultraviolet and soft X-ray photons, primarily at spectral lines of highly ionized C, O, Ne, and Fe. WHIM is thought to be the main reservoir of missing baryons.

→ warm; → hot; → intergalactic medium.

The process of becoming warmer; a rising temperature. → backwarming, → heating.

→ warm; → -ing.

The vertical twisting of a → galactic disk in its outer parts. Many → spiral galaxies, including our Milky Way, appear to have warps in the outer reaches of their stellar and gas disks. The rotating body of stars and gas that characterizes a spiral galaxy is generally flat, but the outer regions may deviate from the plane of the disk. The causes are multiple, some warps can come from spontaneous instability, some result from interactions between galaxies, and many reflect the external gas → accretion from intergalactic matter filaments.

M.E. werpen, OE weorpan "to throw;" cf. O.S. werpan, O.N. verpa "to throw," Swed. värpa "to lay eggs," Du. werpen, Ger. werfen "to throw; to distort." Related to warp "threads running lengthwise in a fabric."

Tâb "twisting, bending, waving, a curling lock," variants tâv, tow, tew, from tâbidan, tâftan "to twist, to spin, to bend, to crook," p.p. tâftah "spun, silk or linen cloth," loaned into E. as taffeta (from O.Fr. taffetas, from It. taffeta); similarly Gk. tapetion "little carpet" is probably from this Iranian origin (from which tapestry, tapis); Proto-Ir. *tâp- "to twist, to wind;" cf. L. tempus "time (span);" Lith. tempti "to stretch;" Russ. tepsti "to tighten."