An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < act Gal int > >>

Number of Results: 49 Search : galactic
Galactic halo
  هاله‌ی ِ کهکشان   
hâle-ye kahkešân

Fr.: halo galactique   

A roughly spherical aggregation of → globular clusters, as well as the oldest stars and unseen mass that surrounds the Galaxy.

galactic, → halo.

Galactic latitude
  ورونای ِ کهکشانی   
varunâ-ye kahkešâni

Fr.: latitude galactique   

In the → Galactic coordinate system, the angle between the line of sight to an object and the → Galactic equator. Galactic latitude, usually represented by the symbol bII, ranges from +90 degrees to -90 degrees.

galactic; → latitude.

Galactic longitude
  درژنا‌ی ِ کهکشانی   
derežnâ-ye kahkešâni

Fr.: longitude galactique   

In the → Galactic coordinate system, the angle between the → Galactic Center and the projection of the object on the → Galactic plane. Galactic longitude, usually represented by the symbol lII, ranges from 0 degrees to 360 degrees.

galactic; → longitude.

galactic nucleus
  هسته‌ی ِ کهکشان   
haste-ye kahkešân

Fr.: noyau de galaxie   

A concentration of stars and gas in the innermost region of a galaxy, sometimes extending over thousands of light-years from the center of the galaxy.

galactic; → nucleus.

galactic outflow
  استچان ِ کهکشانی   
ostacân-e kahkešâni

Fr.: flot galactique   

galactic-scale outflow.

galactic; → outflow.

galactic plane
  هامن ِ کهکشان   
hâmon-e kahkešân

Fr.: plan galactique   

The plane in which the → disk of a → spiral galaxy, such as our → Milky Way, lies.

galactic; → plane.

galactic pole
  قطب ِ کهکشان   
qotb-e kahkešân

Fr.: pôle galactique   

The point on the sky, north or south, at which the galaxy's rotation axis would meet the celestial sphere.

galactic; → pole.

Galactic radio noise
  نوفه‌ی ِ رادیویی ِ کهکشان   
nufe-ye râdioi-ye kahkešân

Fr.: bruit radio de la Galaxie   

A diffuse radio signal that originates outside the solar system. It is strongest in the direction of the Galactic plane.

galactic; → radio; → noise.

galactic rotation
  چرخش ِ کهکشان   
carxeš-e kahkešân

Fr.: rotation galactique   

The revolving of the gaseous and stellar content of a galaxy around its central nucleus. The rotation is not uniform, but differential. One revolution of the Sun within our own Galaxy takes about 220 million years, or one cosmic year.

galactic; → rotation.

galactic rotation problem
  پراسه‌ی ِ چرخش ِ کهکشانی   
parâse-ye carxeš-e kahkešâni

Fr.: problème de la rotation galactique   

The discrepancy between observed galaxy → rotation curves and the theoretical prediction, assuming a centrally dominated mass associated with the observed luminous material.

galactic; → rotation; → problem.

galactic structure
  ساختار ِ کهکشان   
sâxtâr-e kahkešân

Fr.: structure galactique   

The global shape and the arrangement of the various parts or constituents of a galaxy.

galactic; → structure.

Galactic system
  راژمان ِ کهکشانی   
râžmân-e kahkešâni

Fr.: système galactique   

Same as → galactic coordinates.

galactic; → system.

galactic wind
  باد ِ کهکشانی   
bâd-e kahkašâni

Fr.: vent galactique   

An outflow of hot gas, analogous to the → solar wind, from a galaxy that has recently undergone a high → burst of star formation or has an → active galactic nucleus. Galactic winds are streams of high speed charged particles blowing out of galaxies with speeds of 300 to 3,000 km s-1. In the case of starbursts, galactic winds are powered by → stellar winds driven by → massive stars and → supernova explosions. Galactic winds contain a mixture of extremely hot metal-enriched supernova ejecta and cooler entrained gas and dust. Outflowing material has been observed at great distances from galaxies (10 to 100 kpc). In some cases they escape the galaxy potential well and pollute the → intergalactic medium with → heavy elements. A prominent example is the → superwind of the starburst galaxy M82.

galactic; → wind.

Galactic windows
  روزنه‌های ِ کهکشان   
rowzanehâ-ye kahkešân

Fr.: fenêtres galactiques   

The regions near the Galactic plane where there is low absorption of light by interstellar clouds so that some external galaxies may be seen through them.

galactic; → window.

Galactic year
  سال ِ کهکشانی   
sâl-e kahkešâni (#)

Fr.: année galactique   

The time taken for the Sun to revolve once around the center of the Milky Way, amounting to about 220 million years.

galactic; → year.

galactic-scale outflow
  استچان با مرپل ِ کهکشانی   
ostacân bâ marpel-e kahkešâni

Fr.: flot à l'échelle galactique   

The enormous amounts of → mass and → energy released from active galaxies into the → intergalactic medium. → Supermassive black holes, believed to exist at the centres of active galaxies (→ active galaxy), → accrete matter and liberate huge quantities of energy. The energy output is often observed as → active galactic nuclei (AGN) outflows in a wide variety of forms, e.g. → collimated  → relativistic jets and/or huge overpressured cocoons in → radio, → blueshifted broad → absorption lines in the → ultraviolet and → optical, → warm absorbers and ultrafast outflows in → X-rays, and → molecular gas in → far infrared. Moreover, the processes of → star formation and → supernova explosions release mass/energy into the surroundings. This → stellar feedback heats up, ionizes and drives gas outward, often generating large-scale outflows/→ winds. Galactic outflows are observed at low redshifts reaching a velocity as large as 1000 km s-1 and at high-z up to z ~ 5, sometimes extending over distances of 60-130 kpc. Galactic-scale outflows may be a primary driver of galaxy evolution through the removal of cool gas from star-forming regions to a galaxy's → halo or beyond.

galactic; → scale; → outflow.


Fr.: intergalactique   

Of, existing, or occurring in the space between galaxies. → intergalactic absorption, → intergalactic cloud, → intergalactic matter , → intergalactic medium , → warm-hot intergalactic medium.

inter-; → galactic.

intergalactic absorption
  درشم ِ اندرکهکشانی   
daršam-e andarkahkešâni

Fr.: absorption intergalactique   

Absorption features in the spectra of bright sources like → quasars attributed to a tenuous matter filling the medium between galaxies.

intergalactic; → absorption.

intergalactic cloud
  ابر ِ اندرکهکشانی   
abr-e andarkahkešâni

Fr.: nuage intergalactique   

Intergalactic matter in the form of clouds.

intergalactic; → cloud.

intergalactic matter
  مادّه‌ی ِ اندرکهکشانی   
mâdde-ye andarkahkešâni

Fr.: matière intergalactique   

Very low density material found indirectly in the space between galaxies. → intergalactic absorption.

intergalactic; → matter.

<< < act Gal int > >>