Black Hole Spin in X-ray Binaries: Giving Uncertainties an $f$

Abstract

The two established techniques for measuring black hole spin in X-ray binaries often yield conflicting results, which must be resolved before either method may be deemed robust. In practice, black hole spin measurements based on fitting the accretion disc continuum effectively do not marginalize over the colour correction factor $f_{\mathrm{col}}$. This factor parametrizes spectral hardening of the disc continuum by the disc atmosphere, whose true properties are poorly constrained. We incorporate reasonable systematic uncertainties in $f_{\mathrm{col}}$ into the eight (non-maximal) black hole spin measurements vetted by the disc continuum fitting community. In most cases, an $f_{\mathrm{col}}$ uncertainty of $\pm$0.2-0.3 dominates the black hole spin error budget. We go on to demonstrate that plausible departures in $f_{\mathrm{col}}$ values from those adopted by the disc continuum fitting practitioners can bring the discrepant black hole spins into agreement with those from iron line modeling. Systematic uncertainties in $f_{\mathrm{col}}$, such as the effects of strong magnetization, should be better understood before dismissing their potentially dominant impact on the black hole spin error budget.

Minor changes in proofs stage; Data and code are available on GitHub: https://github.com/gregsalvesen/bhspinf

References in corpus (15)

• Global General Relativistic MHD Simulation of a Tilted Black-Hole Accretion Disk
• The magnetic nature of disk accretion onto black holes
• A 15.65 solar mass black hole in an eclipsing binary in the nearby spiral galaxy Messier 33
• The Masses and Spins of Neutron Stars and Stellar-Mass Black Holes
• Testing Accretion Disk Theory in Black Hole X-ray Binaries
• A Determination of the Spin of the Black Hole Primary in LMC X-1
• A Grid of Relativistic, non-LTE Accretion Disk Models for Spectral Fitting of Black Hole Binaries
• Accretion Discs with Strong Toroidal Magnetic Fields
• Strong disc winds traced throughout outbursts in black-hole X-ray binaries
• Angular Momentum Transport in Accretion Disks and its Implications for Spin Estimates in Black Hole Binaries
• An Obscured, Seyfert-2-like State of the Stellar-mass Black Hole GRS 1915+105 Caused by Failed Disk Winds
• Surface Structure in an Accretion Disk Annulus with Comparable Radiation and Gas Pressure
• Disk Dominated States of 4U 1957+11: Chandra, XMM, and RXTE Observations of Ostensibly the Most Rapidly Spinning Galactic Black Hole
• Instability in strongly magnetized accretion discs: A global perspective
• Convective Quenching of Field Reversals in Accretion Disc Dynamos

Cited by in corpus (20)

• Observational Constraints on Black Hole Spin
• Apples and Oranges: Comparing black holes in X-ray binaries and gravitational-wave sources
• Physical origin of the nonphysical spin evolution of MAXI J1820+070
• Which black hole is spinning? Probing the origin of black-hole spin with gravitational waves
• Insight-HXMT Study of the Inner Accretion Disk in the Black Hole Candidate EXO 1846--031
• Black holes: Timing and spectral properties and evolution
• An Electron-Scattering Time Delay in Black Hole Accretion Disks
• Accretion of matter and spectra of Binary X-ray sources in Massive Gravity
• The inner flow geometry in MAXI J1820+070 during hard and hard-intermediate states
• A Dependable Distance Estimator to Black Hole Low-Mass X-ray Binaries
• The black hole spin in GRS 1915+105, revisited
• Formation of Wind-Fed Black Hole High-mass X-ray Binaries: The Role of Roche-lobe-Overflow Post Black-Hole Formation
• Accretion Disc Evolution in GRO J1655-40 and LMC X-3 with Relativistic and Non-Relativistic Disc Models
• A rapid black hole spin or emission from the plunging region?
• Searching for quantum-gravity footprint around stellar-mass black holes
• The population of NuSTAR Black Hole X-ray Binaries
• Binary X-ray sources in massive Brans-Dicke gravity
• Boson Cloud Atlas: Direct mass measurements of superradiance clouds near black holes
• The Spin and Orientation of the Black Hole in XTE J1908$+$094
• A Revised Spin of the Black Hole in GRS 1716-249 with a New Distance