Relativistic Jets and Accretion Phenomena associated with Galactic and Extragalactic Black Holes
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| Natura: | Artículo científico |
| Lingua: | en |
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Sociedade Brasileira de Física
2005
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| _version_ | 1876440656236249088 |
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| author | E. M. de Gouveia Dal Pino |
| author_facet | E. M. de Gouveia Dal Pino |
| contents | Relativistic Jets and Accretion Phenomena associated with Galactic and Extragalactic Black Holes E. M. de Gouveia Dal Pino Física, Astronomía y Matemáticas More than a dozen binary star systems hosting stellar-mass black holes have been discovered in our galaxy.Some of them eject collimated relativistic jets with apparent velocities larger than the light speed. These objectshave been named microquasars thanks to their similarity with the distant quasars or active nuclei of galaxies thathost supermassive black holes. We have recently proposed that the large scale superluminal ejections observedin the microquasars (e.g., GRS 1915+105 source) during radio flare events are produced by violent magneticreconnection episodes in the accretion disk that surrounds the central source, a ten-solar-mass black hole (deGouveia Dal Pino and Lazarian 2005). The process occurs when a large-scale magnetic field is established bya turbulent dynamo in the inner disk region with a ratio between the gas+radiation and the magnetic pressuresβ 1. During this process, substantial angular momentum is removed from the disk by the wind generated bythe vertical magnetic flux therefore increasing the disk mass accretion to a value near (but below) the criticalEddington limit. Part of the magnetic energy released by reconnection heats the coronal gas above the disk thatproduces a steep, soft X-ray spectrum with luminosity consistent with observations. The remaining magneticenergy released goes to accelerate the particles to relativistic velocities (v ∼ vA ∼ c, where vA is the Alfv´enspeed) in the reconnection site through first-order Fermi processes. For the first time we have examined theFermi process within the reconnection zone and found that a power-law electron distribution is produced N(E)∝E−αE , with αE = 5/2, and a corresponding synchrotron radio power-law spectrum with a spectral index whichis compatible with that observed during the flares (Sν ∝ ν−0.75), though a standard Fermi process behind shocksthat develop just above the reconnection site is also possible. The possibility that the ejection mechanism ofrelativistic blobs induced by magnetic reconnection can be applied to all classes of black hole-relativisitc jetsystems, from microquasars to quasars and active galactic nuclei, is addressed here. 2005 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46435743 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.4B Vol.35 |
| format | Artículo científico |
| id | redalyc_46435743 |
| institution | Redalyc |
| language | en |
| publishDate | 2005 |
| publisher | Sociedade Brasileira de Física |
| spellingShingle | Relativistic Jets and Accretion Phenomena associated with Galactic and Extragalactic Black Holes E. M. de Gouveia Dal Pino Física, Astronomía y Matemáticas Relativistic Jets and Accretion Phenomena associated with Galactic and Extragalactic Black Holes E. M. de Gouveia Dal Pino Física, Astronomía y Matemáticas More than a dozen binary star systems hosting stellar-mass black holes have been discovered in our galaxy.Some of them eject collimated relativistic jets with apparent velocities larger than the light speed. These objectshave been named microquasars thanks to their similarity with the distant quasars or active nuclei of galaxies thathost supermassive black holes. We have recently proposed that the large scale superluminal ejections observedin the microquasars (e.g., GRS 1915+105 source) during radio flare events are produced by violent magneticreconnection episodes in the accretion disk that surrounds the central source, a ten-solar-mass black hole (deGouveia Dal Pino and Lazarian 2005). The process occurs when a large-scale magnetic field is established bya turbulent dynamo in the inner disk region with a ratio between the gas+radiation and the magnetic pressuresβ 1. During this process, substantial angular momentum is removed from the disk by the wind generated bythe vertical magnetic flux therefore increasing the disk mass accretion to a value near (but below) the criticalEddington limit. Part of the magnetic energy released by reconnection heats the coronal gas above the disk thatproduces a steep, soft X-ray spectrum with luminosity consistent with observations. The remaining magneticenergy released goes to accelerate the particles to relativistic velocities (v ∼ vA ∼ c, where vA is the Alfv´enspeed) in the reconnection site through first-order Fermi processes. For the first time we have examined theFermi process within the reconnection zone and found that a power-law electron distribution is produced N(E)∝E−αE , with αE = 5/2, and a corresponding synchrotron radio power-law spectrum with a spectral index whichis compatible with that observed during the flares (Sν ∝ ν−0.75), though a standard Fermi process behind shocksthat develop just above the reconnection site is also possible. The possibility that the ejection mechanism ofrelativistic blobs induced by magnetic reconnection can be applied to all classes of black hole-relativisitc jetsystems, from microquasars to quasars and active galactic nuclei, is addressed here. 2005 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46435743 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.4B Vol.35 |
| title | Relativistic Jets and Accretion Phenomena associated with Galactic and Extragalactic Black Holes |
| topic | Física, Astronomía y Matemáticas |
| url | https://www.redalyc.org/articulo.oa?id=46435743 |