Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-08-25
Astrophys.J.631:L101-L104,2005
Astronomy and Astrophysics
Astrophysics
4 pages, accepted for publication in ApJ Letters
Scientific paper
10.1086/497397
The transition of a standard thin disk to a radiatively inefficient accretion flow (RIAF) is expected to occur, when its dimensionless accretion rate is lower than the critical value. The RIAF is very hot, and it radiates mostly in the hard X-ray band (>100 keV). Assuming that the accretion disk in every bright active galactic nucleus (AGN) will finally undergo a RIAF phase while the accretion rate is lower than the critical value, we calculate the contribution of the RIAFs in AGNs to the cosmological X-ray background of 10-1000 keV. We find that the timescale of the RIAF accreting at slightly below the critical rate should be shorter than 0.01 of the bright AGN lifetime if the critical accretion rate is 0.01, i.e., the accretion rate declines from the critical value to a rate significantly lower than this critical rate within this RIAF timescale. The derived RIAF timescale is affected by the parameters adopted in the model calculations, which is also discussed in this Letter.
No associations
LandOfFree
Constraints on radiatively inefficient accretion history of active galactic nuclei from hard cosmological X-ray background does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Constraints on radiatively inefficient accretion history of active galactic nuclei from hard cosmological X-ray background, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Constraints on radiatively inefficient accretion history of active galactic nuclei from hard cosmological X-ray background will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-262765