Fr.: bras local
tangol-e mahali, hobâb-e ~
Fr.: Bulle locale
A region of low density in the → interstellar medium surrounding the → Solar System. It extends at least 300 → light-years in most directions and encompasses the stars of the immediate → solar neighborhood. The Local Bubble contains a hot, million-degree ionized hydrogen gas that emits in → X-rays. → Neutral hydrogen has a density approximately one tenth of the average for the interstellar medium in the Milky Way. The bubble is thought to be a result of the → shock waves from → supernovae sweeping through the region within the past two to four million years.
goruh-e mahali (#)
Fr.: Groupe local
A small cluster of about 40 galaxies to which our Milky Way Galaxy belongs. The Local Group occupies a volume of space nearly 10 million light-years across centered somewhere between the → Andromeda Galaxy (M31) and the Milky Way, which are the dominant galaxies of the group; Andromeda being the principal member. Both of these galaxies exhibit spiral structures, and each is attended by a large family of satellite → dwarf galaxies. The Local Group also includes a third spiral galaxy known as → Triangulum (M33), which is bound to Andromeda. The remaining members span a range of → Hubble classification types from dwarf spheroidal to Irr to Sb and Sc and cover a factor of 10 in → metallicity. The total mass of the Local Group is estimated to be about 2 x 1012 solar masses, although this value is still uncertain to within a factor of about 2. The velocities of the individual galaxies of the Local Group are not particularly high. Therefore no member is believed to be able to escape the group, which is thus considered to be gravitationally → bound. Another remarkable member of the Group is → IC 10.
local inertial frame
cârcub-e laxtnâk-e mahali, ~ laxtimand-e ~
Fr.: référentiel inertiel local
A coordinate system or frame of reference defined in the vicinity of the Earth in which Newton's first law of motion is valid; that is, a non-rotating and non-accelerating reference frame.
local interstellar cloud
abr-e andar-axtari-ye mahali
Fr.: nuage interstellaire local
local Lorentz invariance
nâvartâyi-ye Lorentz-e mahali
Fr.: invariance de Lorentz locale
Fr.: maximum local
Fr.: méridien local
The meridian through any particular place, serving as the reference for local time, in contrast to the Greenwich meridian.
Fr.: minimum local
navešgar-e mahali (#)
Fr.: oscillateur local
The oscillator in a heterodyne or superheterodyne radio receiver which produces the radio frequency oscillations with which the received wave is combined.
local position invariance
nâvartâyi-ye neheš-e mahali
Fr.: invariance de position locale
local sidereal time
zamân-e axtari-ye mahali
Fr.: temps sidéral local
Local time measured by the apparent motion of the stars. It is the most useful form of sidereal time since it gives the right ascension of a transiting celestial object at a given location.
Fr.: bras local
Same as → Orion Arm.
local standard of rest
estânde-ye mahali-ye âram
Fr.: standard local de repos
A frame of reference that turns around the Galactic center at a velocity and a distance which are the mean values for the stars in the solar neighborhood. In this reference system the stars belonging to the solar neighborhood are statistically at rest. The orbital velocity of the Local Standard of Rest around the Galaxy is about 220 km/sec.
abarxuše-ye mahali (#)
Fr.: superamas local
The supercluster to which the Local Group belongs. It is composed of some 100 clusters of galaxies, with the Virgo cluster of galaxies at its center.
local thermodynamic equilibrium (LTE)
tarâzmandi-ye garmâtavânik-e mahali
Fr.: équilibre thermodynamique local
The assumption that all distribution functions characterizing the material and its interaction with the radiation field at a point in the star are given by → thermodynamic equilibrium relations at local values of the temperature and density.
zamân-e mahali (#)
Fr.: temps local
Time based upon the local meridian as reference, in contrast to that of the time zone within which the place is located, or the Greenwich time.
Fr.: Univers local
Local Volume (LV)
Fr.: Volume local
A sphere of radius ~ 10 Mpc centered on the → Local Group of galaxies. The Local Volume includes at least 500 known galaxies, many of which congregate in well-known groups like the Local Group, the relatively loose → Sculptor Group, and the more compact Centaurus A group. As of 2010, the latest catalog of LV galaxies was presented by Karachentsev et al. (2004, AJ 127, 2031). About 85% of the LV population are → dwarf galaxies which contribute to about 4% to the local optical luminosity density and roughly to 10-15% to the total H I mass density.
mahal giri (#)
The condition of the wave-function of an electron if it is confined to a small region of a large system rather than being extended through the system.
Verbal noun of → localize.