New Constraints on the Black Hole Low/Hard State Inner Accretion Flow with NuSTAR

Abstract

We report on an observation of the Galactic black hole candidate GRS 1739-278 during its 2014 outburst, obtained with NuSTAR. The source was captured at the peak of a rising "low/hard" state, at a flux of ~0.3 Crab. A broad, skewed iron line and disk reflection spectrum are revealed. Fits to the sensitive NuSTAR spectra with a number of relativistically blurred disk reflection models yield strong geometrical constraints on the disk and hard X-ray "corona". Two models that explicitly assume a "lamppost" corona find its base to have a vertical height above the black hole of h = 5 (+7, -2) GM/c^2 and h = 18 +/-4 GM/c^2 (90% confidence errors); models that do not assume a "lamppost" return emissivity profiles that are broadly consistent with coronae of this size. Given that X-ray microlensing studies of quasars and reverberation lags in Seyferts find similarly compact coronae, observations may now signal that compact coronae are fundamental across the black hole mass scale. All of the models fit to GRS 1739-278 find that the accretion disk extends very close to the black hole - the least stringent constraint is r = 5 (+3,-4) GM/c^2. Only two of the models deliver meaningful spin constraints, but a = 0.8 +/-0.2 is consistent with all of the fits. Overall, the data provide especially compelling evidence of an association between compact hard X-ray coronae and the base of relativistic radio jets in black holes.

Accepted for publication in ApJ Letters

References in corpus (2)

• The role of the reflection fraction in constraining black hole spin
• Reprocessing of X-rays in the outer accretion disc of the black hole binary XTE J1817--330

Cited by in corpus (31)

• Towards precision measurements of accreting black holes using X-ray reflection spectroscopy
• Reflection Spectra of the Black Hole Binary Candidate MAXI J1535-571 in the Hard State Observed by NuSTAR
• A Systematic View of Ten New Black Hole Spins
• Accretion geometry of the black-hole binary Cygnus X-1 from X-ray polarimetry
• Testing General Relativity with NuSTAR data of Galactic Black Holes
• NuSTAR Observations of the Black Hole GS 1354-645: Evidence of Rapid Black Hole Spin
• Systematically Revisiting All NuSTAR Spins of Black Holes in X-Ray Binaries
• Detection of X-ray spectral state transitions in mini-outbursts of black hole transient GRS 1739-278
• Studying the Reflection Spectra of the New Black Hole X-ray Binary Candidate MAXI J1631-479 Observed by NuSTAR: A Variable Broad Iron Line Profile
• Testing the performance and accuracy of the RELXILL model for the relativistic X-ray reflection from accretion disks
• The current state of disk wind observations in BHLMXBs through X-ray absorption lines in the iron band
• Spectral and Timing Properties of IGR J17091-3624 in the Rising Hard State During its 2016 Outburst
• Broad-band spectral study of X-ray transient MAXI J1820+070 using Swift/XRT and NuSTAR
• Detection of Very Low-Frequency Quasi-Periodic Oscillations in the 2015 Outburst of V404 Cygni
• Evidence for Disk Truncation at Low Accretion States of the Black Hole Binary MAXI J1820+070 Observed by NuSTAR and XMM-Newton
• High-density reflection spectroscopy of black hole X-ray binaries in the hard state
• Black holes: Timing and spectral properties and evolution
• The black hole X-ray transient Swift J1357.2-0933 as seen with Swift and NuSTAR during its 2017 outburst
• GRS 1739-278 observed at very low luminosity with XMM-Newton and NuSTAR
• Spectral and polarization properties of reflected X-ray emission from black-hole accretion discs for a distant observer: the lamp-post model
• Reflection and timing study of the transient black hole X-ray binary MAXI J1803-298 with NuSTAR
• X-ray spectral correlations in a sample of Low-mass black hole X-ray binaries in the hard state
• A retrograde spin of the black hole in MAXI J1659--152
• The outburst of the X-ray nova GRS 1739-278 in September, 2016
• Broadband Spectral properties of MAXI J1348--630 using AstroSat Observations
• Impact of ionization and electron density gradients in X-ray reflection spectroscopy measurements
• A Spectroscopic Angle on Central Engine Size Scales in Accreting Neutron Stars
• Accretion flows in the hard state of black hole X-ray binaries: the effect of hot gas condensation
• The Reliability of Accretion Disk Inclination Derived from X-ray Spectroscopy of Active Galaxies
• Investigation of the Outburst Activity of the Black Hole Candidate GRS 1739-278
• On the Relation between the Inclination Angle of the Accretion Disk and the Broad-line Region in Active Galactic Nuclei