Optical and Ultraviolet Monitoring of the Black Hole X-ray Binary MAXI J1820+070/ASASSN-18ey for 18 Months

Abstract

MAXI J1820+070 is a low-mass black hole X-ray binary system with high luminosity in both optical and X-ray bands during the outburst periods. We present extensive photometry in X-ray, ultraviolet, and optical bands, as well as densely-cadenced optical spectra, covering the phase from the beginning of optical outburst to $\sim$550 days. During the rebrightening process, the optical emission preceded the X-ray by 20.80 $\pm$ 2.85 days. The spectra are characterized by blue continua and emission features of Balmer series, He I, He II lines and broad Bowen blend. The pseudo equivalent width (pEW) of emission lines are found to show anticorrelations with the X-ray flux measured at comparable phases, which is due to the increased suppression by the optical continuum. At around the X-ray peak, the full width at half maximums (FWHMs) of H${}_{\beta }$ and He II $\lambda$4686 tend to stabilize at 19.4 Angstrom and 21.8 Angstrom, which corresponds to the line forming region at a radius of 1.7 and 1.3 R_sun within the disk. We further analyzed the absolute fluxes of the lines and found that the fluxes of H${}_{\beta }$ and He II $\lambda$4686 show positive correlations with the X-ray flux, favoring that the irradiation model is responsible for the optical emission. However, the fact that X-ray emission experiences a dramatic flux drop at t$\sim$200 days after the outburst, while the optical flux only shows little variations suggests that additional energy such as viscous energy may contribute to the optical radiation in addition to the X-ray irradiation.

arXiv commentAccepted for publication in MNRAS

References in corpus (41)

• X-ray Properties of Black-Hole Binaries
• The Swift Ultra-Violet/Optical Telescope
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• The disc instability model of dwarf-novae and low-mass X-ray binary transients
• The MAXI Mission on the ISS: Science and Instruments for Monitoring All Sky X-Ray Images
• Going with the flow: can the base of jets subsume the role of compact accretion disk coronae?
• The Properties of X-Ray and Optical Light Curves of X-Ray Novae
• The disc instability model for X-ray transients: evidence for truncation and irradiation
• Near-infrared synchrotron emission from the compact jet of GX339-4
• Global optical/infrared - X-ray correlations in X-ray binaries: quantifying disc and jet contributions
• Mass Measurements of Stellar and Intermediate Mass Black-Holes
• Gas Slit Camera (GSC) onboard MAXI on ISS
• X-ray irradiation in XTE J1817-330 and the inner radius of the truncated disc in the hard state
• Reprocessing of X-rays in the outer accretion disc of the black hole binary XTE J1817--330
• A radio parallax to the black hole X-ray binary MAXI J1820+070
• Swift Observations of the Cooling Accretion Disk of XTE J1817-330
• The spectral evolution of AT 2018dyb and the presence of metal lines in tidal disruption events
• Gaia DR2 Distances and Peculiar Velocities for Galactic Black Hole Transients
• Crab: the standard X-ray candle with all (modern) X-ray satellites
• Dynamical confirmation of a black hole in MAXI J1820+070
• ASASSN-18ey: The Rise of a New Black-Hole X-ray Binary
• Hard-state accretion disk winds from black holes: the revealing case of MAXI J1820+070
• The Photometric System of Tsinghua-NAOC 80-cm Telescope at NAOC Xinglong Observatory
• X-ray and Optical Monitoring of State Transitions in MAXI J1820+070
• Events leading up to the June 2015 outburst of V404 Cyg
• The Mass of the Black Hole in the X-ray Binary Nova Muscae 1991
• Optical Spectroscopy of GX339-4 during the High-Soft and Low-Hard States II: Line Ionisation and Emission Region
• Optical precursors to X-ray binary outbursts
• The 1989 and 2015 outbursts of V404 Cygni: a global study of wind-related optical features
• Accretion and Outflow in V404 Cyg
• A Method to Search for Black Hole Candidates with Giant Companions by LAMOST
• An ``outside-in'' outburst of Aql X--1
• The Oxygen Features in Type Ia Supernovae and the Implications for the Nature of Thermonuclear Explosions
• An anti-correlation between X-ray luminosity and H-alpha equivalent width in X-ray binaries
• Spectroscopy of Infrared Flares from the Microquasar GRS 1915+105
• Evolving optical polarisation of the black hole X-ray binary MAXI J1820+070
• A Dynamical Study of the Black Hole X-ray Binary Nova Muscae 1991
• The Night Sky Spectrum of Xinglong Observatory: Changes from 2004 to 2015
• The relation between outburst rate and orbital period in low-mass X-ray binary transients
• Formation of optical lines in black-hole binaries

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• A full spectral-timing model to map the accretion flow in black hole binaries: the low/hard state of MAXI J1820+070
• Multiwavelength observations of MAXI J1820+070 during its outburst decay and subsequent mini-outburst
• TUVOpipe: a pipeline to search for UV transients with Swift-UVOT
• Evolution of Accretion Disk Structure of the Black Hole X-ray Binary MAXI J1820$+$070 during the Rebrightening Phase
• Ubiquitous yet forgotten: broad absorptions in the optical spectra of low-mass X-ray binaries