Puzzling accretion onto a black hole in the ultraminous X-ray source

1. Puzzling accretion onto a black hole in the ultraminous X-ray source Authors: Ji-Feng Liu, Joel N. Bregman, Yu Bai, Stephen Justham & paul Crowther Reporter: Jun xu

2. Ultraluminous X-ray source Intermediate-mass black holes 100-1000 Msun sub-Eddington rate cooler disc Stellar-mass black holes <30 Msun (super-)Eddington Company Logo

3. M101 ULX-1:supersoft thermal disk spectrum with exceptionally low temperature M101 M101 ULX-1

4. Wolf-Rayet star • Evolved massive stars • over 20 solar masses when on the main sequence • strong stellar wind(2000 km/s) • Losing mass rapidly(10-5 solar masses a year) • Strong broad emission lines • Helium,Nitrogen,Carbon • Weak or none Hydrogen

6. Empirical mass-luminosity relation • MWR=19Msun

9. The measure of MBH depends on i • Lower inclination angles, higher black-hole masses • MBH=20Msun(stellar mass black hole),when i=19 degree • MBH=1000Msun(IMBH),when i=3 degree • 4.6 Msun<MBH<1000 Msun

10. Compare with similar system

12. To capture stellar wind matter • Use terminal velocity • MBH>46Msun, η=0.06(non-spinning Schwarzschild black hole) • MBH>13Msun, η=0.42(maximally spinning Kerr black hole) • Use radial velocity • MBH>28Msun, η=0.06(non-spinning Schwarzschild black hole) • MBH>8Msun, η=0.42(maximally spinning Kerr black hole) Likely to be a black hole of 10Msun-30Msun !

13. Conclusion: • M101 ULX-1 is not a classic ULX • Stellar wind capture is not so inefficient as it was thought to be • Other previously IMBH powered ULX may be stellar mass black hole

14. Thank you !