Black hole growth by accretion
Abstract
We show that black holes grow substantially by accretion at close to Eddington rates. Using a complete sample of soft X-ray selected AGNs, Grupe & Mathur (2004, ApJ, 606, L41) have shown that narrow line Seyfert 1 galaxies, as a class, lie below the MBH-σ relation of normal galaxies. Some NLS1s, however, lie on or close to the MBH-σ relation. Here we show that not all NLS1s accrete at close to Eddington rates: those with low L/LEddington are close to the MBH-σ relation, and those with high L/LEddington are far from it. With various tests in this paper, we argue that black holes grow in mass substantially in their high-accretion phase and approach the MBH-σ relation over time. The mass growth in a low accretion phase, as in BLS1s and also in some NLS1s, appears to be insignificant. Any theoretical model attempting to explain the MBHσ relation needs to explain the above observations.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 2005
- DOI:
- 10.1051/0004-6361:20041717
- arXiv:
- arXiv:astro-ph/0407512
- Bibcode:
- 2005A&A...432..463M
- Keywords:
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- black hole physics;
- galaxies: active;
- galaxies: evolution;
- X-rays: galaxies;
- Astrophysics
- E-Print:
- Submitted to A&