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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 24 Search : source
ultraluminous X-ray source (ULX)
  خن ِ پرتو ِ ایکس ِ اولتر-تابان   
xan-e partow-e iks-e ultar-tâbân

Fr.: source ultralumineuse en rayons X   

An X-ray source that is not in the nucleus of a galaxy, and is more luminous than 1039 ergs s-1, brighter than the → Eddington luminosity of a 10 → solar mass → black hole. In general, there is about one ULX per galaxy in galaxies which host ULXs. The Milky Way contains no such objects. ULXs are thought to be powered by → accretion onto a → compact object. Possible explanations include accretion onto → neutron stars with strong → magnetic fields, onto → stellar black holes (of up to 20 → solar masses) at or in excess of the classical Eddington limit, or onto → intermediate-mass black holes (103-105 solar masses). NGC 1313X-1, NGC 5408X-1, and NGC 6946X-1 are three ULXs with X-ray luminosities up to ~ 1040 erg s-1 (Ciro Pinto et al., 2016, Nature 533, N) 7601).

ultraluminous; → X-ray source.

unresolved source
  خن ِ ناواگشوده   
xan-e nâvâgošudé

Fr.: source non résolue   

A source of radiation whose angular size is too small for details of its structure to be revealed.

unresolved; → source.

X-ray source
  خن ِ پرتو ِ ایکس   
xan-e partow-e iks

Fr.: source de rayons X   

An astronomical object whose dominant mechanism of radiation is through X-ray emission. X-ray sources contain an extremely hot gas at temperatures from 106 to 108 K. They are generated by various physical processes involving high energies, such as accretion on to a compact object, shock waves from supernovae, stellar winds, hot gas in stellar coronae, or hot spaces between galaxies in a cluster. The first celestial X-ray source, after the Sun, to be detected was → Scorpius X-1 by means of rocket flight (Giacconi et al. 1962).

X-ray; → source.

Z source
  خن ِ Z   
xan-e Z

Fr.: source Z   

A member of a class of → low-mass X-ray binary systems containing low-magnetic field → neutron stars. See also → atoll source.

The name derives from the fact that on X-ray → color-color diagrams Z sources usually form a Z shape that is traced on timescales of hours to days; → source

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