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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

   Homepage   
   


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Number of Results: 5 Search : non-thermal
non-thermal
  ناگرمایی   
nâgarmâyi

Fr.: non thermique   

The nature of a → non-thermal radiation.

non-; → thermal.

non-thermal emission
  گسیل ِ ناگرمایی   
gosil- nâgarmâyi (#)

Fr.: émission non thermique   

non-thermal radiation.

non-thermal; → emission.

non-thermal filament (NTF)
  رشته‌ی ِ ناگرمایی   
rešte-ye nâgarmâyi

Fr.: filament non thermique   

Any of many long and slender structures visible in → radio continuum images of the inner hundred parsecs of the → Galactic Center. NTFs are typically tens of parsecs long and only a fraction of parsec wide. They may occur in isolation or in bundles, such as those comprising the linear portion of the prominent → radio Arc. Their → non-thermal spectrum and strong → linear polarization indicate → synchrotron radiation. The magnetic fields in the NTFs have been estimated from various means. Early estimates centered on the radio Arc, and focused on a comparison between the → magnetic pressure and the estimated → ram pressure from nearby → molecular cloud interactions, indicated magnetic field strengths as high as 1 mG (Morris and Yusef-Zadeh 1985). More recent observations, however, have pointed to significantly weaker magnetic fields among the population of NTFs. Synchrotron models of the radio spectrum imply equipartition magnetic fields between 50-200 μG. Theoretically, it has been challenging to understand the nature of these filaments that resemble extragalactic → radio jets but are not accompanied with any obvious source of acceleration of charged particles to high energy → relativistic energies. Although a number of detailed models have been considered, there is no consensus as to the origin of the NTFs. These models suggest that molecular and ionized gas clouds, mass-losing stars, → Galactic winds, magnetic activity of the → supermassive black hole at the Galactic center, and → lepton production due to → dark matter annihilation play a role in the processes that lead to the production of the NTFs (Linden et al. 2011, ApJ 741,95, and references therein). In most models, the magnetic field is strong and its global geometry in the central region of the Galaxy is considered to be → poloidal and static. However, some recent models have argued that the magnetic field is local and dynamic.

non-thermal; → filament.

non-thermal radiation
  تابش ِ ناگرمایی   
tâbeš-e nâgarmâyi (#)

Fr.: rayonnement non thermique   

The electromagnetic radiation whose characteristics do not depend on the temperature of the emitting source. In contrast to → thermal radiation, it has a different spectrum from that of → blackbody radiation. The three common types of non-thermal radiation in astronomy are: → synchrotron radiation, → bremsstrahlung radiation, and → maser  → stimulated emission.

non-thermal; → radiation.

non-thermal spectrum
  بیناب ِ ناگرمایی   
binâb-e nâgarmâyi

Fr.: spectre non thermique   

A radio emission with a negative → spectral index. In this type of emission the intensity of the emitted radiation increases with wavelength.

non-thermal; → spectrum.