Open AccessDetermining the spin of two stellar‐mass black holes from disc reflection signatures
Author(s) -
Reis R. C.,
Fabian A. C.,
Ross R. R.,
Miller J. M.
Publication year - 2009
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2009.14622.x
Subject(s) - physics , dimensionless quantity , black body radiation , astrophysics , black hole (networking) , spin (aerodynamics) , orbital plane , reflection (computer programming) , orbital inclination , rotating black hole , astronomy , radiation , accretion (finance) , optics , quantum mechanics , arithmetic , mathematics , computer network , routing protocol , programming language , routing (electronic design automation) , binary number , computer science , thermodynamics , link state routing protocol
We present measurements of the dimensionless spin parameters and inner‐disc inclination of two stellar‐mass black holes. The spin parameter of SWIFT J1753.5−0127 and GRO J1655−40 is estimated by modelling the strong reflection signatures present in their XMM–Newton observations. Using a newly developed, self‐consistent reflection model which includes the blackbody radiation of the disc as well as the effect of Comptonization, blurred with a relativistic line function, we infer the spin parameter of SWIFT J1753.5−0127 to be 0.76 +0.11 −0.15 . The inclination of this system is estimated at 55° +2 −7 . For GRO J1655−40, we find that the disc is significantly misaligned to the orbital plane, with an innermost inclination of 30° +5 −10 . Allowing the inclination to be a free parameter, we find a lower limit for the spin of 0.90, this value increases to that of a maximal rotating black hole when the inclination is set to that of the orbital plane of J1655−40. Our technique is independent of the black hole mass and distance, uncertainties in which are among the main contributors to the spin uncertainty in previous works.