# Near-horizon circular orbits and extremal limit for dirty rotating black holes

@article{Zaslavskii2015NearhorizonCO, title={Near-horizon circular orbits and extremal limit for dirty rotating black holes}, author={Oleg B. Zaslavskii}, journal={Physical Review D}, year={2015}, volume={92}, pages={044017} }

We consider generic rotating axially symmetric "dirty" (surrounded by matter) black holes. Near-horizon circular equatorial orbits are examined in two different cases of near-extremal (small surface gravity $\kappa $) and exactly extremal black holes. This has a number of qualitative distinctions. In the first case, it is shown that such orbits can lie as close to the horizon as one wishes on suitably chosen slices of space-time when $\kappa \rightarrow 0$. This generalizes observation of T…

## 17 Citations

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## References

SHOWING 1-8 OF 8 REFERENCES

### Phys

- Rev. D 83 024002
- 2011

### Quantum Grav

- 2011

### Phys

- Rev. Lett. 103, 111102
- 2009

### Phys

- Rev. D 88 024042 (2013)
- 2013

### Phys

- 18, 1727
- 1976

### Phys

- Rev. D 86, 044019
- 2012

### Phys

- Rev. Lett. 104, 021101
- 2010

### Phys

- Rev. D 82
- 2010