PMID- 24284727
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20131223
LR  - 20211021
IS  - 1476-4687 (Electronic)
IS  - 0028-0836 (Linking)
VI  - 503
IP  - 7477
DP  - 2013 Nov 28
TI  - Puzzling accretion onto a black hole in the ultraluminous X-ray source M 101 
      ULX-1.
PG  - 500-3
LID - 10.1038/nature12762 [doi]
AB  - There are two proposed explanations for ultraluminous X-ray sources (ULXs) with 
      luminosities in excess of 10(39) erg s(-1). They could be intermediate-mass black 
      holes (more than 100-1,000 solar masses, M sun symbol) radiating at sub-maximal 
      (sub-Eddington) rates, as in Galactic black-hole X-ray binaries but with larger, 
      cooler accretion disks. Alternatively, they could be stellar-mass black holes 
      radiating at Eddington or super-Eddington rates. On its discovery, M 101 ULX-1 
      had a luminosity of 3 x 10(39) erg s(-1) and a supersoft thermal disk spectrum 
      with an exceptionally low temperature--uncomplicated by photons energized by a 
      corona of hot electrons--more consistent with the expected appearance of an 
      accreting intermediate-mass black hole. Here we report optical spectroscopic 
      monitoring of M 101 ULX-1. We confirm the previous suggestion that the system 
      contains a Wolf-Rayet star, and reveal that the orbital period is 8.2 days. The 
      black hole has a minimum mass of 5 M sun symbol, and more probably a mass of 20 M 
      sun symbol-30 M sun symbol, but we argue that it is very unlikely to be an 
      intermediate-mass black hole. Therefore, its exceptionally soft spectra at high 
      Eddington ratios violate the expectations for accretion onto stellar-mass black 
      holes. Accretion must occur from captured stellar wind, which has hitherto been 
      thought to be so inefficient that it could not power an ultraluminous source.
FAU - Liu, Ji-Feng
AU  - Liu JF
AD  - Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese 
      Academy of Sciences, 20A Datun Road, Chaoyang District, 100012 Beijing, China.
FAU - Bregman, Joel N
AU  - Bregman JN
FAU - Bai, Yu
AU  - Bai Y
FAU - Justham, Stephen
AU  - Justham S
FAU - Crowther, Paul
AU  - Crowther P
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - England
TA  - Nature
JT  - Nature
JID - 0410462
CIN - Nature. 2013 Nov 28;503(7477):477-8. PMID: 24284725
EDAT- 2013/11/29 06:00
MHDA- 2013/11/29 06:01
CRDT- 2013/11/29 06:00
PHST- 2013/04/01 00:00 [received]
PHST- 2013/09/27 00:00 [accepted]
PHST- 2013/11/29 06:00 [entrez]
PHST- 2013/11/29 06:00 [pubmed]
PHST- 2013/11/29 06:01 [medline]
AID - nature12762 [pii]
AID - 10.1038/nature12762 [doi]
PST - ppublish
SO  - Nature. 2013 Nov 28;503(7477):500-3. doi: 10.1038/nature12762.