Characterizing the quiescent X-ray variability of the black hole low mass x-ray binary V404 Cyg

Abstract

We conducted the first long-term (75 days) X-ray monitoring of the black hole low mass X-ray binary V404 Cyg, with the goal of understanding and characterizing its variability during quiescence. The X-ray light curve of V404 shows several flares on timescales of hours with a count rate change of a factor of about 5-8. The root mean square variability is Fvar = 57.0(3.2) percent. The first order structure function is consistent with both a power spectrum of index -1 (flicker noise), or with a power spectrum of index 0 (white noise), implying that the light curve is variable on timescales from days to months. The X-ray spectrum is well fitted by a power law with spectral index Γ = 2.10 - 2.35, and we found that the spectral shape remains roughly constant as the flux changes. A constant spectral shape with respect to a change in the X-ray flux may favour a scenario in which the X-ray emission is dominated by synchrotron radiation produced in a jet.

11 pages, 7 figures, 2 tables, accepted on MNARS on January 16 2014

References in corpus (6)

• X-ray Properties of Black-Hole Binaries
• Advection-Dominated Accretion and the Black Hole Event Horizon
• Radiatively Inefficient Accretion in Nearby Galaxies
• Paper II: Calibration of the Swift ultraviolet/optical telescope
• The spectral energy distribution of quiescent black hole X-ray binaries: new constraints from Spitzer
• Zooming in on a sleeping giant: milliarcsecond HSA imaging of the black hole binary V404 Cyg in quiescence

Cited by in corpus (26)

• The radio/X-ray domain of black hole X-ray binaries at the lowest radio luminosities
• The gas-to-extinction ratio and the gas distribution in the Galaxy
• Living on a Flare: Relativistic Reflection in V404 Cyg Observed by NuSTAR During its Summer 2015 Outburst
• Furiously Fast and Red: Sub-second Optical Flaring in V404 Cyg during the 2015 Outburst Peak
• The 2015 Decay of the Black Hole X-ray Binary V404 Cygni: Robust Disk-Jet Coupling and a Sharp Transition into Quiescence
• Events leading up to the June 2015 outburst of V404 Cyg
• The Quiescent X-ray Spectrum of Accreting Black Holes
• Constraints on Relativistic Jets in Quiescent Black Hole X-ray Binaries from Broadband Spectral Modeling
• Characterizing X-ray and Radio emission in the Black Hole X-Ray Binary V404 Cygni during Quiescence
• Broad-band characteristics of seven new hard X-ray selected cataclysmic variables
• Multiwavelength observations of the black hole X-ray binary A0620-00 in quiescence
• Accretion and Outflow in V404 Cyg
• A Clean Sightline to Quiescence: Multiwavelength Observations of the High Galactic Latitude Black Hole X-ray Binary Swift J1357.2-0933
• Radio Variability from a Quiescent Stellar Mass Black Hole Jet
• Jet-dominated quiescent states in black hole X-ray binaries: the case of V404 Cyg
• On the Optical -- X-ray correlation from outburst to quiescence in Low Mass X-ray Binaries: the representative cases of V404 Cyg and Cen X-4
• Polarized synchrotron emission in quiescent black hole X-ray transients
• Optical and X-ray Correlations During the 2015 Outburst of the Black Hole V404 Cyg
• Toward a Larger Sample of Radio Jets from Quiescent Black Hole X-ray Binaries
• ALMA observations of A0620-00: fresh clues on the nature of quiescent black hole X-ray binary jets
• On the recurrence times of neutron star X-ray binary transients and the nature of the Galactic Centre quiescent X-ray binaries
• Swift UVOT observations of the 2015 outburst of V404 Cygni
• Searching for Compact Object Candidates from LAMOST Time-Domain Survey of Four K2 Plates
• The flickering radio jet from the quiescent black hole X-ray binary A0620-00
• Jet-dominated quiescent state in black hole X-ray binaries: the cases of A0620--00 and XTE J1118+480
• Very-high-energy observations of the binaries V 404 Cyg and 4U 0115+634 during giant X-ray outbursts