A precise measurement of the magnetic field in the corona of the black hole binary V404 Cygni

Dallilar, Y.; Eikenberry, S. S.; Garner, Alan; Stelter, R. Deno; Gottlieb, Amy; Gandhi, P.; Casella, P.; Dhillon, V. S.; Marsh, T. R.; Littlefair, S. P.; Hardy, L. K.; Fender, R. P.; Mooley, K. P.; Walton, D. J.; Fuerst, F.; Bachetti, Matteo; Castro‐Tirado, A. J.; Charcos, Miguel; Edwards, Michelle L.; Lasso-Cabrera, N. M.; Marín-Franch, A.; Raines, S. N.; Ackley, K.; Bennett, John G.; Cenarro, A. J.; Chinn, Brian; Donoso, H. Veronica; Frommeyer, Raymond; Hanna, Kevin; Herlevich, Michael D.; Julian, Jeff; Miller, Paola; Mullin, Scott A.; Murphey, Charles H.; Packham, C.; Városi, F.; Vega, Claudia; Warner, C.; Ramaprakash, A. N.; Burse, Mahesh; Punnadi, Sujit; Chordia, Pravin; Gerarts, Andreas; Martín, Héctor de Paz; Calero, María Martín; Scarpa, Riccardo; Acosta, Sergio Fernandez; Sánchez, William Miguel Hernández; Siegel, Benjamin M.; Pérez, Francisco Francisco; Martín, Himar D. Viera; Losada, José; Núñez, Agustín Riscos; Tejero, A.; González, Carlos E. Martín; Rodríguez, César Cabrera; Molgo, J.; Rodríguez, J.; Caceres, J.I.F.; García, Luis A. Rodríguez; Lopez, Manuel Huertas; Dominguez, Raul; Gaggstatter, Tim; Lavers, A. Cabrera; Geier, S.; Pessev, Peter; Sarajedini, Ata

doi:10.1126/science.aan0249

Cited by 38 publications

(24 citation statements)

References 35 publications

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“…On June 18 we see the decay sustained for 1000 s, and on June 19 for 400 s, both much longer than light travel times could account for. Similar behaviour is seen in multiwavelength observations by Tetarenko et al (2017) and examined in detail by Dallilar et al (2017); we will discuss this further in Sections 7.3 and 7.5. When present the flaring can have large amplitude ( < ∼ 0.5 mag) on timescales of a few seconds.…”

Section: Smooth Decayssupporting

confidence: 74%

“…It probably arises in direct jet emission, although the timescale is much shorter than that estimated above for plasmon ejection (Gandhi et al 2016(Gandhi et al , 2017, suggesting a different variability mechanism. Direct optical emission from the corona has also been proposed by Dallilar et al (2017).Alfonso-Garzón et al (2018) considered similar possibilities for flares with no optical lag. Based on NuSTAR, Swift, and INTEGRAL observations an X-ray picture of the central source geometry has emerged, although many features remain in question.…”

Section: Rapid Variability and The Central Engine Geometrymentioning

confidence: 93%

“…A one minute lag would also be consistent with light travel timescales across the disc, so it remains possible that either the slow optical variations arise from direct emission from the plasmons, or from irradiation of the disc or wind by the X-ray flares, or by a combination of both mechanisms. Dallilar et al (2017) have instead argued that decay events similar to those shown in Section 3.2 occur in stationary material in the corona or base of the jet with the optical decay reflecting synchrotron cooling with no change in magnetic field, rather than the expansion of ejecta.…”

Section: Are Slow Variations Driven By Plasmon Ejections or Disc Irramentioning

confidence: 98%

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Optical and X-ray correlations during the 2015 outburst of the black hole V404 Cyg

Hynes

Robinson

Terndrup

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present a serendipitous multiwavelength campaign of optical photometry simultaneous with Integral X-ray monitoring of the 2015 outburst of the black hole V404 Cyg. Large amplitude optical variability is generally correlated with X-rays, with lags of order a minute or less compatible with binary light travel timescales or jet ejections. Rapid optical flaring on time-scales of seconds or less is incompatible with binary lighttravel timescales and has instead been associated with synchrotron emission from a jet. Both this rapid jet response and the lagged and smeared one can be present simultaneously. The optical brightness is not uniquely determined by the X-ray brightness, but the X-ray/optical relationship is bounded by a lower-envelope such that at any given optical brightness there is a maximum X-ray brightness seen. This lowerenvelope traces out a F opt ∝ F 0.54 X relation which can be approximately extrapolated back to quiescence. Rapid optical variability is only seen near this envelope, and these periods correspond to the hardest hard X-ray colours. This correlation between hard X-ray colour and optical variability (and anti-correlation with optical brightness) is a novel finding of this campaign, and apparently a facet of the outburst behaviour in V404 Cyg. It is likely that these correlations are driven by changes in the central accretion rate and geometry.

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Section: Smooth Decayssupporting

confidence: 74%

Section: Rapid Variability and The Central Engine Geometrymentioning

confidence: 93%

Section: Are Slow Variations Driven By Plasmon Ejections or Disc Irramentioning

confidence: 98%

See 1 more Smart Citation

Optical and X-ray correlations during the 2015 outburst of the black hole V404 Cyg

Hynes

Robinson

Terndrup

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…(4) detection of e − e + pair annihilation and γ-ray excess, in support for plasmoid ejections in a jet (Siegert et al 2016;Loh et al 2016;Piano et al 2017) (5) evidence for discrete relativistic ejections in a precessing jet and strong disc-jet coupling Plotkin et al 2017;Tetarenko et al 2017) (6) a tight constraint on the size of the jet launching/collimation region (Gandhi et al 2017) (7) a measurement of the magnetic field in the accretion disc corona (Dallilar et al 2018).…”

Section: Introductionmentioning

confidence: 96%

Accretion and outflow in V404 Cyg

Casares

Muñoz-Darias

Sánchez

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We study the optical evolution of the 2015 outburst in V404 Cyg, with emphasis on the peculiar nebular phase and subsequent decay to quiescence. From the decay timescale of the Balmer emission associated with the nebula we measure an outflow mass M wind 4 × 10 −6 M . Remarkably, this is ∼100 times larger than the accreted mass and ∼10% of the total mass stored in the disc. The wind efficiency must therefore be significantly larger than previous estimates for black hole transients, suggesting that radiation pressure (in addition to other mechanisms such as Compton-heating) plays a key role in V404 Cyg. In addition, we compare the evolution of the 2015 and 1989 outbursts and find clear similarities (namely a large luminosity drop ∼10 d after the X-ray trigger, followed by a brief nebular phase) but also remarkable differences in decay timescales and long-term evolution of the Hα profile. In particular, we see evidence for a rapid disc contraction in 2015, consistent with a burst of mass transfer. This could be driven by the response of the companion to hard X-ray illumination, most notably during the last gigantic (super-Eddington) flare on 25 June 2015. We argue that irradiation and consequential disc wind are key factors to understand the different outburst histories in 1989 and 2015. In the latter case, radiation pressure may be responsible for the abrupt end of the outburst through depleting inner parts of the disc, thus quenching accretion and X-ray irradiation. We also present a refined orbital period and updated ephemeris.

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“…But in this case the values of the coupling parameters should naturally be considered as undetermined, and it moreover seems probable that they will be dependent on the field configurations and energy regimes. The solutions based on non-minimal coupling were analysed in various settings which, however, so far were mostly only of theoretical interest [41][42][43][44][45][46][47][48][49] Apart from the existence of the galactic magnetic field, there is also convincing observational evidence for the presence of magnetic fields in the vicinity of the Black Hole of our own Galaxy [50,51] as well as close to Black Hole binaries [52,53]. The presence of magnetic fields around Black Holes is important since it influences different astrophysical processes, such as the formation of relativistic jets [54].…”

Section: Introductionmentioning

confidence: 99%

Influence of the vacuum polarization effect on the motion of charged particles in the magnetic field around a Schwarzschild black hole

Pavlović¹,

Saveliev

Sossich

2019

Phys. Rev. D

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The consequences of the vacuum polarization effect in magnetic fields around a Schwarzschild Black Hole (SBH) on the motion of charged particles are investigated in this work. Using the weak electromagnetic field approximation, we discuss the non-minimal coupling between magnetic fields and gravity caused by the vacuum polarization and study the equations of motion for the case of a magnetic field configuration which asymptotically approaches a dipole magnetic field. It is shown that the presence of non-minimal coupling can significantly influence the motion of charged particles around Black Holes. In particular, the vacuum polarization effect, leading to strong amplification or suppression of the magnetic field strength around the event horizon (depending on the sign of the coupling parameter), can affect the scattering angle and minimal distance for the electrons moving in the gravitational field of the Black Hole as well as the dependence of these parameters on the asymptotic magnetic field strength, initial distance and the Black Hole mass. It is further demonstrated that the non-minimal coupling between gravity and astrophysical magnetic fields, caused by the vacuum polarization, can cause significant changes of the parameter space corresponding to bound trajectories around the Black Hole. In certain cases, the bounded or unbounded character of a trajectory is determined solely by the presence of non-minimal coupling and its strength. These effects could in principle be used as observational signatures of the vacuum polarization effect and also to constrain the value of the coupling parameter.

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A precise measurement of the magnetic field in the corona of the black hole binary V404 Cygni

Cited by 38 publications

References 35 publications

Optical and X-ray correlations during the 2015 outburst of the black hole V404 Cyg

Optical and X-ray correlations during the 2015 outburst of the black hole V404 Cyg

Accretion and outflow in V404 Cyg

Influence of the vacuum polarization effect on the motion of charged particles in the magnetic field around a Schwarzschild black hole

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