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.
1) mahal dâdan; 2) mahal gereftan
Fr.: 1) localise; 2) se localiser
1) To confine, restrict, or attribute to a particular locality.
1) qofl (#); 2) qofl kardan, ~ šodan
Fr.: 1) vérouille; 2) vérouiller, se vérouiller
1) A device fitted to a gate, door, drawer, lid, etc, to keep it firmly closed and
often to prevent access by unauthorized persons.
M.E., from O.E. loc "fastening, bar;" cognate with M.L.G. lok, O.H.G. loh "dungeon," Ger. Loch "opening, hole," O.N. lok "a cover, lid;" akin to O.E. lucan "to shut."
Qofl, loan from Ar.
Fr.: trou de Lockman
A region in the sky lying roughly between the → pointer stars of the → Big Dipper that is almost free from → neutral hydrogen gas in the → Galaxy. It is centered at R.A. 10h 45m, Dec. +57° 20', has an area of 15 square degrees, and a → column density of NH I ≤ 5 x 1018 cm-2. The Lockman hole is one of the favorite directions for obtaining a clear and unobstructed view of objects in deep space, far beyond our own Galaxy.
Named after Felix J. Lockman et al., 1986, ApJ 302, 432; → hole.
Fr.: lieu géométrique
The aggregate of all possible positions of a moving or generating element, e.g. the locus of points equidistant from a given point is a circle whose center is the given point.
From L. locus "place," from Old L. stlocus, literally "where something is placed," from PIE base *st(h)el- "to cause to stand, to place."
Mahalgân, from mahal "place, locality" + -gân relation and multiplicity suffix.
Named after Lodhran (Punjab), Pakistan, where the type specimen fell on 1 October 1868.
A low frequency radio telescope network concentrated in the Netherlands with extensions into other European countries. It consists of a core and an extended → array in the Netherlands as well as in surrounding European countries with maximum → baselines of 2 km, 100 km, and 1,000 km respectively. LOFAR will be the largest radio telescope ever built, using a new concept based on a vast array of simple omni-directional antennas. The array will operate at the lowest frequencies that can be observed from Earth, at 30-250 MHz. About 75% of the construction is finished and LOFAR has already started its → commissioning period. When entirely finished, it will consist of 45,000 small antennas, distributed within 48 stations in the north east of the Netherlands, nearby parts of Germany, the UK, France, Sweden, and perhaps later Poland and Spain. The extensions in the United Kingdom, Germany, and France are completed. The French extension, located in the Nançay station of Paris Observatory (190 km south of Paris), is fully operational since December 2010. Moreover, a project to extend the low-frequency component of the Nançay station is under study. LOFAR is a forerunner of the future → Square Kilometer Array (SKA) project. See also the LOFAR homepage.
The → exponent of the → power to which it is necessary to raise a fixed number to produce the given number. The fixed number is called the → base. The logarithm of x to the base a, denoted loga(x), is the unique → real number y such that ay = x. In the familiar system of → common logarithms, the base is 10. In the system of → natural logarithms, the base is e = 2.7182818 ... (→ number e). For example, the logarithm of 100 (base 10) is 2 because 102 = 100.
Of or pertaining to a → logarithm.
Fr.: extinction logarithmique
Same as → reddening coefficient.
Fr.: échelle logarithmique
A scale of measurement in which an increase of one unit represents a tenfold increase in the quantity measured (for common logarithms)