Dynamical confirmation of a black hole in MAXI J1820+070

Abstract

We present time-resolved 10.4-m GTC and 4.2-m WHT intermediate resolution spectroscopy of the X-ray transient MAXI J1820+070 (=ASASSN-18ey) obtained during its decline to the quiescent state. Cross-correlation of the 21 individual spectra against late-type templates reveals a sinusoidal velocity modulation with a period of 0.68549 +/- 0.00001 d and semi-amplitude of 417.7 +/- 3.9 km/s. We derive a mass function f(M) = 5.18 +/- 0.15 Msun, dynamically confirming the black hole nature of the compact object. Our analysis of the stellar absorption features supports a K3-5 spectral classification for the donor star, which contributes 20% of the total flux at 5200-6800 Angs. The photometric 0.703 +/- 0.003 d periodicity observed during outburst is 2.6% longer than the orbital period supporting the presence of a superhump modulation in the outburst lightcurves. In line with this interpretation, we constrain the binary mass ratio to be q=0.12. In addition, we observe a sharp increase in the Halpha emission line equivalent width during inferior conjunction of the donor star that we interpret as a grazing eclipse of the accretion disc and allows us to constrain the binary inclination to > 69 deg. On the other hand, the absence of X-ray eclipses during outburst imply i < 77 deg. These inclination limits, together with our dynamical solution, lead to a black hole mass in the range 7-8 Msun. We also measure a systemic velocity = -21.6 +/- 2.3 km/s which, combined with the Gaia DR2 proper motion and parallax, implies a large peculiar velocity of 100 km/s.

7 pages, 3 figures, accepted for publcation in ApJ Letters

References in corpus (4)

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• X-ray and Optical Monitoring of State Transitions in MAXI J1820+070
• X-ray dips and a complex UV/X-ray cross-correlation function in the black hole candidate MAXI J1820+070
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Cited by in corpus (74)

• An extremely powerful long-lived superluminal ejection from the black hole MAXI J1820+070
• Discovery of oscillations above 200 keV in a black hole X-ray binary with Insight-HXMT
• A radio parallax to the black hole X-ray binary MAXI J1820+070
• The binary mass ratio in the black hole transient MAXI J1820+070
• Disk, Corona, Jet Connection in the Intermediate State of MAXI J1820+070 Revealed by NICER Spectral-Timing Analysis
• Insight-HXMT observations of jet-like corona in a black hole X-ray binary MAXI J1820+070
• A rapid change in X-ray variability and a jet ejection in the black hole transient MAXI J1820+070
• Accretion Geometry in the Hard State of the Black-Hole X-Ray Binary MAXI J1820+070
• Measuring fundamental jet properties with multi-wavelength fast timing of the black hole X-ray binary MAXI J1820+070
• The Soft State of the Black Hole Transient Source MAXI J1820+070: Emission from the Edge of the Plunge Region?
• Relativistic X-ray jets from the black hole X-ray binary MAXI J1820+070
• The Varying Kinematics of Multiple Ejecta from the Black Hole X-ray Binary MAXI J1820+070
• Near-infrared emission lines trace the state-independent accretion disc wind of the black hole transient MAXI J1820+070
• Estimating the black hole spin for the X-ray binary MAXI J1820+070
• A full spectral-timing model to map the accretion flow in black hole binaries: the low/hard state of MAXI J1820+070
• Population Synthesis of Black Hole X-Ray Binaries
• A Black Hole X-ray Binary at $\sim$100 Hz: Multiwavelength Timing of MAXI J1820+070 with HiPERCAM and NICER
• Black hole spin-orbit misalignment in the X-ray binary MAXI J1820+070
• The observed mass distribution of Galactic black hole LMXBs is biased against massive black holes
• Physical origin of the nonphysical spin evolution of MAXI J1820+070
• Evidence for mass-dependent peculiar velocities in compact object binaries: Towards better constraints on natal kicks
• The evolution of the broadband temporal features observed in the black-hole transient MAXI J1820+070 with Insight-HXMT
• Dynamical confirmation of a black hole in the X-ray transient Swift J1727.8-1613
• A spectral study of the black hole X-ray binary MAXI J1820+070 with AstroSat and NuSTAR
• The Changing-look Optical Wind of the Flaring X-ray Transient Swift J1858.6-0814
• Dynamical confirmation of a stellar-mass black hole in the transient X-ray dipping binary MAXI J1305-704
• A timing-based estimate of the spin of the black hole in MAXI J1820+070
• A spectrally stratified hot accretion flow in the hard state of MAXI J1820+070
• Discovery of optical and infrared accretion disc wind signatures in the black hole candidate MAXI J1348-630
• The current state of disk wind observations in BHLMXBs through X-ray absorption lines in the iron band
• A detailed view of low-frequency quasi-periodic oscillation in the broadband 0.2-200 keV with Insight-HXMT and NICER
• Orbital period dependent spatial scatter of Galactic Black Hole Transients
• Dips and eclipses in the X-ray binary Swift J1858.6-0814 observed with NICER
• Observations of the Disk/Jet Coupling of MAXI J1820+070 During its Descent to Quiescence
• The Evolution of Rapid Optical/X-ray Timing Correlations in the Initial Hard State of MAXI J1820+070
• Chasing the break: Tracing the full evolution of a black hole X-ray binary jet with multi-wavelength spectral modeling
• Delimiting the black hole mass in the X-ray transient MAXI J1659-152 with H$\alpha$ spectroscopy
• Investigating the impact of vertically extended coronae on X-ray reverberation mapping
• The accretion flow geometry of MAXI J1820+070 through broadband noise research with Insight-HXMT
• Accretion geometry of the black hole binary MAXI J1820+070 probed by frequency-resolved spectroscopy
• Evidence for Disk Truncation at Low Accretion States of the Black Hole Binary MAXI J1820+070 Observed by NuSTAR and XMM-Newton
• Multiwavelength observations of MAXI J1820+070 during its outburst decay and subsequent mini-outburst
• Accretion Scenario of MAXI J1820+070 during 2018 Outbursts with Multi-mission Observations
• The Donor of the Black-Hole X-Ray Binary MAXI J1820+070
• Disc and wind in black hole X-ray binary MAXIJ1820+070 observed through polarized light during its 2018 outburst
• MAXI J1820+070 with NuSTAR II. Flaring during the hard to soft state transition with a long soft lag
• A multi-wavelength study of the hard and soft states of MAXI J1820+070 during its 2018 outburst
• Gamma-ray observations of MAXI J1820+070 during the 2018 outburst
• Determination of QPO properties in the presence of strong broad-band noise: a case study on the data of MAXI J1820+070
• An Overview of Compact Star Populations and Some of Its Open Problems
• Ask The Machine: Systematic detection of wind-type outflows in low-mass X-ray binaries
• Optical and Ultraviolet Monitoring of the Black Hole X-ray Binary MAXI J1820+070/ASASSN-18ey for 18 Months
• Science with the $AstroSat$ Soft X-ray Telescope: an overview
• Multiwavelength Observations of the Black Hole X-ray Binary MAXI J1820$+$070 in the Rebrightening Phase
• Evidence for a dynamic corona in the short-term time lags of black hole X-ray binary MAXI J1820+070
• Intermittent QPO properties of MAXI J1820+070 revealed by Insight-HXMT
• Accretion Properties and Estimation of Spin of Galactic Black Hole Candidate Swift J1728.9-3613 with NuSTAR during its 2019 outburst
• Broadband X-ray Spectroscopy and Estimation of Spin of the Galactic Black Hole Candidate GRS 1758-258
• Infrared interferometry to spatially and spectrally resolve jets in X-ray binaries
• Evolution of Accretion Disk Structure of the Black Hole X-ray Binary MAXI J1820$+$070 during the Rebrightening Phase
• The Accretion-Ejection Connection in the Black Hole X-ray Binary MAXI J1820$+$070
• Variable QPO lags and reduced coherence between the disc and corona in MAXI J1820+070
• Investigating the consistency of the shape and flux of X-ray reflection spectra in the hard state with an accretion disk reaching close to the black hole
• Ubiquitous yet forgotten: broad absorptions in the optical spectra of low-mass X-ray binaries
• Tracking optical variability and outflows across the accretion states of the black hole transient MAXI J1820+070
• An apparent positive relation between spin and orbital angular momentum in X-ray binaries
• X-ray time lag evaluation of MAXI J1820+070 with a differential cross-correlation analysis
• Tracking the evolution of the accretion flow in MAXI J1820+070 during its hard state with the JED-SAD model
• Optical and X-ray timing analysis of the 2018-2020 outburst and rebrightening of the black-hole transient MAXI J1820+070
• An infrared FWHM-$K_2$ correlation to uncover highly reddened quiescent black holes
• Observational Biases and Improved Modelling of Off-axis Relativistic Jets
• The complex spectral behavior of the newly discovered neutron star X-ray binary Swift J1858.6-0814
• Recent MAGIC results on Galactic binaries
• Large optical modulations during 2018 outburst of MAXI J1820+070 reveal evolution of warped accretion disc through X-ray state change