High-precision optical polarimetry of the accreting black hole V404 Cyg during the June 2015 outburst

Abstract

Our simultaneous three-colour ($BVR$) polarimetric observations of the low-mass black hole X-ray binary V404 Cyg show a small but statistically significant change of polarization degree ($\Delta p\sim 1$ per cent) between the outburst in June 2015 and the quiescence. The polarization of V404 Cyg in the quiescent state agrees within the errors with that of the visually close (1\farcs4) companion ($p_R=7.3\pm 0.1$ per cent), indicating that it is predominantly of interstellar origin. The polarization pattern of the surrounding field stars supports this conclusion. From the observed variable polarization during the outburst we show that polarization degree of the intrinsic component peaks in the $V$-band, $p_V=1.1\pm 0.1$ per cent, at the polarization position angle of ${\theta }_V=-7°\pm 2°$, which is consistent in all three passbands. We detect significant variations in the position angle of the intrinsic polarization in $R$ band from $-30°$ to $\sim 0°$ during the outburst peak. The observed wavelength dependence of the intrinsic polarization does not support non-thermal synchrotron emission from a jet as a plausible mechanism, but is in better agreement with the combined effect of electron (Thomson) scattering and absorption in a flattened plasma envelope or outflow surrounding the illuminating source. Alternatively, the polarization signal can be produced by scattering of the disc radiation in a mildly relativistic polar outflow. The position angle of the intrinsic polarization, nearly parallel to the jet direction (i.e. perpendicular to the accretion disc plane), is in agreement with these interpretations.

12 pages, 9 figures, 4 tables; Accepted to MNRAS

References in corpus (15)

• Super-critically accreting stellar-mass black holes as ultraluminous X-ray sources
• Regulation of black-hole accretion by a disk wind during a violent outburst of V404 Cygni
• Hot accretion flow in black hole binaries: a link connecting X-rays to the infrared
• Correlated optical, X-ray, and gamma-ray flaring activity seen with INTEGRAL during the 2015 outburst of V404 Cygni
• Repetitive Patterns in Rapid Optical Variations in the Nearby Black-hole Binary V404 Cygni
• High Resolution Chandra HETG spectroscopy of V404 Cygni in Outburst
• An overview of jets and outflows in stellar mass black holes
• Jet contributions to the broad-band spectrum of Cyg X-1 in the hard state
• The formation of the black hole in the X-ray binary system V404 Cyg
• Time-resolved optical/near-IR polarimetry of V404 Cyg during its 2015 outburst
• No Evidence of Intrinsic Optical/Near-Infrared Linear Polarization for V404 Cygni During its Bright Outburst in 2015: Broadband Modeling and Constraint on Jet Parameters
• MASTER optical polarization variability detection in the Microquasar V404 Cyg/GS2023+33
• The nova-like nebular optical spectrum of V404 Cygni at the beginning of the 2015 outburst decay
• Measurement of Interstellar Polarization and Estimation of Galactic Extinction for the Direction of X-ray Black Hole Binary V404 Cygni
• High-precision broad-band linear polarimetry of early-type binaries I. Discovery of variable, phase-locked polarization in HD 48099

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