1) belk; 2) belkidan
Fr.: 1) sursaut, flambée, impulsion; 2) éclater
1a) General: An abrupt, intense increase. A period of intense
activity. A sudden outbreak or outburst. An explosion.
M.E. bersten, from O.E. berstan, akin to O.H.G. berstan "to burst;" from PIE *bhres- "to burst, break, crack."
1) Belk, Mod.Pers. "a blaze, a flame." The term has several
variants, including in dialects: balk [Mo'in],
pâlk (Tokharian AB),
bal (Gilaki, Semnâni, Sorxeyi, Sangesari, Lahijâni),
val (Gilaki), bilese (Kordi), beleyz (Lori),
warq, barx [Mo'in], and the Pers. widespread term gorr
"burst of fire."
Belk derives probably from Mid.Pers. brâh, Av. braz-
"to shine, gleam, flash, radiate,"
cf. Skt. bhâ- "to shine," bhrajate "shines, glitters,"
O.H.G. beraht "bright,"
O.E. beorht "bright;" PIE *bhereg- "to shine."
The Mod.Pers. barq "glitter; → electricity" probably
belongs to this family. Therefore, the Hebrew barak and Ar. barq
may be loanwords from Old or Mid.Pers.
burst of star formation
belk-e diseš-e setâregân
Fr.: flambée de formation d'étoiles
An intense → star formation activity in a region of → interstellar medium or, more globally, in a → galaxy. It is characterized by a → star formation rate which is much higher than the corresponding average. Same as → starburst.
Fr.: source à sursaut
From → burst + -er a noun-forming suffix.
Belkvar, from belk, → burst, + agent noun suffix -var.
Ragbâr, from rag + bâr. The second component bâr, variant bârân "rain," from bâridan "to rain." The origin of the first component is not clear. Rag in Persian means "blood vein, vessel," but this sense seems irrelevant here. In Gilaki the bare râk (without bâr) means cloudburst. Râk/rag may be related (via an extinct Iranian parent) to the Skt. stem ri- "to flow, to drop, to become liquid."
belk-e partowhâ-ye keyhâni
Fr.: sursaut de rayons cosmiques
An intense beam of cosmic rays coming from any direction on the sky, which originates outside the solar system.
fast radio burst (FRB)
belk-e râdioyi-ye tond
Fr.: sursaut radio rapide, impulsion ~ ~
A bright → burst of → radio emission lasting only a few milliseconds, and thought to be of → extragalactic origin. The first ever detected such burst, called the → Lorimer burst, was in 2007. It lasted only 5 milliseconds, but the single radio → pulse was dispersed over a wide range of frequencies (→ dispersion measure). This suggested a → cosmic origin for the burst, because the radiation must have passed through very distant → intergalactic clouds to be so highly dispersed. The second FRB was detected in 2012 in archival data from the Parkes Radio Telescope, the same telescope through which the original burst was seen. No temporally coincident → X-ray or → gamma ray signature was identified in association with the bursts. Most recent results suggest FRBs as a new population of explosive events at cosmological distances of up to 3 → giga → parsecs, that is → redshifts of 0.5 to 1. While physical interpretations for this phenomenon remain speculative, they are thought to involve highly → compact objects, such as → neutron stars. See also → blitzar.
gamma-ray burst (GRB)
belk-e partowhâ-ye gâmmâ
Fr.: sursaut de rayons gamma
An intense discharge of → gamma rays, which range in duration from tenth of a second to tens of seconds and occur from sources widely distributed over the sky. The radio wave → afterglow from the → burst can last more than a year, making long-term observations of the sources possible. The favored hypothesis is that they are produced by a relativistic jet created by the merger of two → compact objects (specifically two → neutron stars or a neutron star and a → black hole). Mergers of this kind are also expected to create significant quantities of neutron-rich radioactive species, whose decay should result in a faint → transient, known as a → kilonova, in the days following the burst. Indeed, it is speculated that this mechanism may be the predominant source of stable → r-process elements in the Universe. Recent calculations suggest that much of the kilonova energy should appear in the → near-infrared spectral range, because of the high optical opacity created by these heavy r-process elements (Tanvir et al., 2017, Nature 500, 547).
belkvar-e partow-e gâmmâ
Fr.: source à sursaut gamma
belk-e padâkvâr, ~ pâypâyé
Fr.: sursaut graduel
A burst that happens gradually, in contrast to a sudden burst.
Fr.: sursaut Lorimer, impulsion ~
The first ever discovered → fast radio burst. It was done during a search of archival data from a 1.4-GHz survey of the → Magellanic Clouds using the multi-beam receiver on the 64-m Parkes Radio Telescope in Australia.
D. R. Lorimer et al., 2007, Science, 318, 777; → burst.
A hypothetical → transient event undergone by a → star due to its violent → merging with another star in a → close binary star. The release of → orbital energy causes the → envelope of the star to heat up and → inflate, causing the star to brighten considerably. Mergebursts are predicted to rival or exceed the brightest classical → novae in luminosity, but to be much cooler and redder than classical novae, and to become slowly hotter and bluer as they age.
1) A fairly brief period of unusually strong gas and/or dust production from a
A phase in the → light curve evolution of eruptive objects such as → dwarf novae, → Soft X-ray Transients, and transient → magnetars which follows the characterized sudden increase in their flux (over a factor ~ 1000 over the quiescent level). Outburst decay is slow and lasts months or years.
Fr.: sursaut radio
A burst of emission in the radio frequencies of the electromagnetic spectrum.
Fr.: source à sursaut rapide
An object with technical designation MXB 17302335 which is characterized by erratic and extremely intense → X-ray emissions. The Rapid Burster is a → binary system comprising a → low-mass star as its → primary and a → secondary → neutron star. The → gravitational attraction of the neutron star strips its → companion of some of its gas, which then forms an → accretion disk and spirals toward the neutron star. The Rapid Burster is located at a distance of 110 kpc in the highly reddened → globular cluster Liller 1. It is a → low-mass X-ray binary (LMXB) and a recurrent → X-ray transient. So far less than 200 LMXBs have been detected in the → Galaxy and the → Magellanic Clouds. All produce a persistent flux of X-rays, the result of a release of → gravitational potential energy. Approximately 40 of them also exhibit → Type I bursts which are due to → thermonuclear flashes on the surface of a neutron star. The Rapid Burster is unique among the LMXBs in that it produces X-ray bursts in quick succession. These are called → Type II bursts, and they result from a spasmodic release of gravitational potential energy, which is due to some unknown → accretion disk instability (Lewin et al., 1996, ApJ 462, L39).
setâre-belk, belk-e setâré
Fr.: flambée d'étoiles
Simultaneous formation of a large number of stars in a region of a galaxy at an exceptionally high rate, compared to the usual star formation rates seen in most galaxies.
Fr.: galaxie à flambée d'étoiles
A galaxy showing a short-lived intense period of star formation that is unsustainable over the → Hubble time due to the limited supply of gas within a galaxy. Starburst galaxies were first classified by Searle & Sargent (1972) and Searle et al. (1973), based on the blue colors produced by the → massive stars formed during the burst. In the local Universe, starbursts create approximately 10% of the radiant energy and 20% of the massive stars. At z = 1, starburst characteristics are found in 15% of galaxies, presumably attributable to the greater amounts of gas typically present in young galaxies and increased galactic interactions. The starburst's impact on a galaxy and the surrounding → intergalactic medium is primarily due to the consumption of gas that fuels the burst and the feedback from massive stars formed in the burst (McQuinn et al. 2010, astro-ph/1008.1589).
Type I burst
belk-e gune-ye I
Fr.: sursaut de type I
A burst of → X-rays observed toward → low-mass X-ray binary (LMXB)s. It is characterized by a sharp increase in → luminosity, which lasts 1-10 s, followed by the peak and a slow decrease, which can last from ~ 10s to 100s. Observationally, X-ray bursts manifest as a bright peak of emission on top of the persistent emission powered by → accretion. See also → Type II burst.
Type II burst
belk-e gune-ye II
Fr.: sursaut de type II
A burst of → X-rays observed toward → low-mass X-ray binary (LMXB)s and characterized by quick succession of bursts with recurrence intervals as short as ~ 7 s. Type II X-ray bursts look similar to → Type I bursts, but they are thought to be related with spasmodic episodes of → accretion.
belk-e partow-e iks
Fr.: sursaut de rayonnement X
A rapid and intense surge of X-ray emission from some sources. They often last less than one second followed by an exponential decrease of typically a few seconds to a minute. Most X-ray bursts are believed to arise in → X-ray binary systems due to nuclear fusion of material accreted onto a compact companion.