Magnetic fields in active galactic nuclei and microquasars

• Published in: Monthly notices of the Royal Astronomical Society Vol. 342; no. 4; pp. 1325 - 1333
• Main Authors: Zakharov, A. F., Kardashev, N. S., Lukash, V. N., Repin, S. V.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 11.07.2003
• Subjects: 6-30-15; black hole physics; galaxies: individual: MCG; galaxies: Seyfert
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1046/j.1365-8711.2003.06638.x

Observations of active galactic nuclei and microquasars by ASCA, RXTE, Chandra and XMM–Newton indicate the existence of wide X-ray emission lines of heavy ionized elements in their spectra. The emission can arise in the inner parts of accretion discs where the effects of general relativity must be counted; moreover, such effects can dominate. We describe a procedure to estimate an upper limit of the magnetic fields in the regions where X-ray photons are emitted. We simulate typical profiles of the iron Kα line in the presence of a magnetic field and compare them with observational data. As an illustration, we find H > 1010–1011 Gs for Seyfert galaxy MCG–6-30-15. Using the perspective facilities of measurement devices (e.g. Constellation-X mission) a better resolution of the blue peak structure of the iron Kα line will allow us to find the value of the magnetic fields if the latter are high enough.