1998/10/15 by Heino Falcke, H. Falcke, Falcke, Heino +2
Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Heat Transfer Mechanisms #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9810226
Astronomy & Astrophysics, A&A Latex, 9 pages, 2 PS figures, also available at http://www.mpifr-bonn.mpg.de/mpivlb/falcke/publications.html#jdiii
arxiv created 1998/10/15 · openalex publication_date 1998/10/15 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We have derived simplified equations for a freely expanding, pressure driven jet model as a function of jet power and applied it successfully to the radio cores in the black hole candidates GRS 1915+105, NGC 4258, and M81 which are observationally well defined systems, and to Sgr A*. By using equipartition assumptions, the model has virtually no free parameters and can explain all sources by just scaling the jet power. In GRS 1915+105 it also naturally explains the jet velocity and the radio time delay. The jet powers we derive for the radio cores of the first three sources are comparable to their accretion disk luminosities, providing further evidence for the existence of symbiotic jet/disk systems and a common engine mechanism also in low-luminosity AGN and stellar mass black holes. With the exception of Sgr A* an advection dominated accretion flow (ADAF) does not seem to be necessary to explain any of the radio cores which span a large range in luminosity and size, as well as in black hole masses and accretion rate---from Eddington to extreme sub-Eddington. We suggest, however, that the jet model can be used to derive minimum accretion rates and thus find that Sgr A* seems to be truly radiatively deficient---even in a starved black hole model---and that a combination of jet and ADAF model may be one possible solution.