• DOI:10.1051/0004-6361:20041717
• Corpus ID: 15736260

Black hole growth by accretion

@article{Grupe2004BlackHG,
  title={Black hole growth by accretion},
  author={Smita MathurDirk Grupe},
  journal={Astronomy and Astrophysics},
  year={2004},
  volume={432},
  pages={463-466}
}

• Smita MathurDirk Grupe
• Published 23 July 2004
• Physics
• Astronomy and Astrophysics

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 MBH-σ relation needs to explain the above observations.