Microquasar
Amicroquasar,the smaller version of aquasar,is a compact region surrounding astellar black holewith a mass several times that of itscompanion star.[1]The matter being pulled from the companionstarforms anaccretion diskaround theblack hole.This accretion disk may become so hot, due to friction, that it begins to emitX-rays.[2]The disk also projects narrow streams or "jets"of subatomic particles at near-light speed,generating a strongradio waveemission.
Overview[edit]
In 1979,SS 433became the first microquasar to be discovered. It was thought to be the most exotic case until similar objects such asGRS 1915+105were discovered in 1994.[2]
In some cases, blobs or "knots" of brighterplasmawithin the jets appear to be traveling faster than the speed of light, anoptical illusioncalledsuperluminal motionwhich is caused by sub-light-speed particles being projected at a small angle relative to the observer.[2]
The 1996Bruno Rossi Prizeof the American Astronomical Society was awarded to Felix Mirabel and Luis Rodríguez for their discovery of thesuperluminal motionof radio knots in GRS 1915+105, as well as the discovery of double-sided radio jets from galactic sources1E1740.7-2942andGRS 1758-258.[3][4][5]
Due to the smaller size of microquasars, many of the effects are scaled differently in relation to normal quasars. In quasars, the mean temperature of theaccretion diskis several thousand degrees, while in a microquasar the mean temperature is several million degrees. The average size of the accretion disk of a quasar is 1 billion square kilometres (390 million square miles), whereas in microquasars the average size is only 1,000 km2(390 sq mi). Quasars can project jets up to several millionlight-years,whereas microquasars can project them only a few light-years; however, the "knots" within the jets of microquasars can exhibit aproper motion(angular motion across the sky) on the order of a thousand times faster than that of knots within a quasar jet because observed microquasars (being within theMilky Waygalaxy) are at typical distances on the order of kiloparsecs,rather than hundreds of megaparsecs to several gigaparsecs.[6]
See also[edit]
References[edit]
- ^"First Microquasar Found Beyond Our Milky Way".nrao.edu.Retrieved19 January2017.
- ^abc"Microquasars in the Milky Way".nrao.edu.Retrieved19 January2017.
- ^"HEAD AAS Rossi Prize Winners".head.aas.org.Retrieved27 August2017.
- ^Mirabel, Felix; Rodriguez, Luis F. (1994). "A superluminal source in the Galaxy".Nature.371(6492): 46–48.Bibcode:1994Natur.371...46M.doi:10.1038/371046a0.S2CID4347263.
- ^Mirabel, Felix (1994). "Multiwavelength approach to gamma-ray sources in the Galactic center region".Astrophys. J. Suppl. Ser.92:369–373.Bibcode:1994ApJS...92..369M.doi:10.1086/191980.
- ^"Microquasars as sources of high energy phenomena -I.F. Mirabel".ned.ipac.caltech.edu.Retrieved19 January2017.
