The Evolution of Rapid Optical/X-ray Timing Correlations in the Initial Hard State of MAXI J1820+070

Abstract

We report on a multi-epoch campaign of rapid optical/X-ray timing observations of the superbright 2018 outburst of MAXI J1820+070, a black hole low-mass X-ray binary system. The observations spanned 80 days in the initial hard-state, and were taken with NTT/ULTRACAM and GTC/HiPERCAM in the optical (ugriz filters at time resolutions of 8--300 Hz) and with ISS/NICER in X-rays. We find (i) a growing anti-correlation between the optical and X-ray lightcurves, (ii) a steady, positive correlation at an optical lag of 0.2 s (with a longer lag at longer wavelengths) present in all epochs, and (iii) a curious positive correlation at \textit{negative} optical lags in the last, X-ray softest epoch, with longer wavelengths showing a greater correlation and a more negative lag. To explain these we postulate the possible existence of two synchrotron-emitting components; a compact jet and a hot flow. In our model, the significance of the jet decreases over the outburst, while the hot flow remains static (thus, relatively, increasing in significance). We also discuss a previously discovered quasi-periodic oscillation and note how it creates coherent optical time lags, stronger at longer wavelengths, during at least two epochs.

19 pages, 13 figures. Accepted for publication to MNRAS

References in corpus (25)

• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• ULTRACAM: an ultra-fast, triple-beam CCD camera for high-speed astrophysics
• The corona contracts in a black-hole transient
• An extremely powerful long-lived superluminal ejection from the black hole MAXI J1820+070
• A radio parallax to the black hole X-ray binary MAXI J1820+070
• Hot accretion flow in black hole binaries: a link connecting X-rays to the infrared
• Rapid optical and X-ray timing observations of GX 339-4: flux correlations at the onset of a low/hard state
• The spectral energy distribution of compact jets powered by internal shocks
• Hard-state accretion disk winds from black holes: the revealing case of MAXI J1820+070
• X-ray and Optical Monitoring of State Transitions in MAXI J1820+070
• A jet model for Galactic black-hole X-ray sources: Some constraining correlations
• 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?
• SWIFT J1753.5-0127: a surprising optical/X-ray cross-correlation function
• Near-infrared emission lines trace the state-independent accretion disc wind of the black hole transient MAXI J1820+070
• A unified accretion-ejection paradigm for black hole X-ray binaries. IV. Replication of the 2010--2011 activity cycle of GX 339-4
• A Black Hole X-ray Binary at $\sim$100 Hz: Multiwavelength Timing of MAXI J1820+070 with HiPERCAM and NICER
• X-ray dips and a complex UV/X-ray cross-correlation function in the black hole candidate MAXI J1820+070
• A timing study of MAXI J1820+070 based on Swift/XRT and NICER monitoring in 2018/19
• Can Lense-Thirring precession produce QPOs in supersonic accretion flows?
• Interference as an origin of the peaked noise in accreting X-ray binaries
• Fast infrared variability from the black-hole candidate MAXI J1535$-$571 and tight constraints on the modelling
• Reprocessing model for the optical quasi-periodic oscillations in black hole binaries
• Sub-second variability in black-hole X-ray binary jets

Cited by in corpus (9)

• HiPERCAM: a quintuple-beam, high-speed optical imager on the 10.4-m Gran Telescopio Canarias
• A variable corona during the transition from type-C to type-B quasi-periodic oscillations in the black hole X-ray binary MAXI J1820+070
• Are Low-Frequency Quasi-Periodic Oscillations seen in accretion flows the disk response to a jet instability?
• Accretion Scenario of MAXI J1820+070 during 2018 Outbursts with Multi-mission Observations
• A rapid optical and X-ray timing study of the neutron star X-ray binary Swift J1858.6-0814
• Intermittent QPO properties of MAXI J1820+070 revealed by Insight-HXMT
• X-ray time lag evaluation of MAXI J1820+070 with a differential cross-correlation analysis
• Evolution of X-ray and optical rapid variability during the low/hard state in the 2018 outburst of MAXI J1820+070 = ASASSN-18ey
• Large optical modulations during 2018 outburst of MAXI J1820+070 reveal evolution of warped accretion disc through X-ray state change