Liverpool-Maidanak monitoring of the Einstein Cross in 2006–2019

Goicoechea, L. J.; Артамонов, Б. П.; Shalyapin, V. N.; Sergeyev, A.; Бурхонов, О.; Akhunov, T.; Asfandiyarov, I. M.; Bruevich, V. V.; Ehgamberdiev, S. A.; Shimanovskaya, E. V.; Zheleznyak, A. P.

doi:10.1051/0004-6361/202037902

Cited by 11 publications

(6 citation statements)

References 51 publications

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“…This constraint affects the BLR models through the condition r in ≥ r s . Between 1500 Å and 3000 Å restframe, the size of the continuum source was found to scale as λ p , where p is between 0.8 and 1.3 (Eigenbrod et al 2008b;Muñoz et al 2016;Goicoechea et al 2020). We could thus expect a factor 4 between the size of the continuum source at the wavelength of Hα and its size at the wavelength of C iv.…”

Section: Probability Of the Different Modelsmentioning

confidence: 99%

Geometry and kinematics of the broad emission line region in the lensed quasar Q2237+0305

Hutsemékers

Sluse

2021

A&A

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Line profile distortions are commonly observed in gravitationally lensed quasar spectra. These distortions are caused by microlensing from the stars in the lensing galaxy, which produce differential magnification of spatially and kinematically separated parts of the broad line region (BLR). The quasi-simultaneous visible and near-infrared spectroscopy of the lensed quasar Q2237+0305 reveals strong microlensing-induced line deformations in the high-ionization C IVλ1549 Å and the low-ionization Hα emission lines. We use this effect to constrain the BLR size, geometry, and kinematics in Q2237+0305. For this purpose, we modeled the deformation of the emission lines for three representative BLR models: a Keplerian disk, an equatorial wind, and a biconical polar wind. We considered various inclinations with respect to the line of sight. We find that the observed microlensing effect, characterized by a set of four indices, can only be reproduced by a subsample of the considered BLR models. The microlensing analysis favors a Keplerian disk model for the regions emitting the C IV and the Hα emission lines. A polar wind model remains possible for the C IV BLR, although it is less likely. The equatorial wind model is totally excluded. A preferred inclination of the BLR of 40° is found, in agreement with expectations for a type 1 AGN and past constraints on the accretion disk inclination. The half-light radius of the BLR is r1/2 ≃ 47 ± 19 light-days, with no significant difference between the C IV and Hα BLRs. The size of the C IV BLR agrees with the radius-luminosity relation derived from reverberation mapping, while the size of the Balmer line BLR is one order of magnitude smaller, possibly revealing different quasar properties at high luminosities and high accretion rates.

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Section: Probability Of the Different Modelsmentioning

confidence: 99%

Geometry and kinematics of the broad emission line region in the lensed quasar Q2237+0305

Hutsemékers

Sluse

2021

A&A

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“…on a timescale of years) are observed in most of the lensed systems and are often used to set constraints on the accretion disk size (see e.g. Morgan et al 2018;Cornachione et al 2020, for recent measurements) or on the temperature profile of the disk (Eigenbrod et al 2008;Goicoechea et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Evidence for a milliparsec-separation Supermassive Binary Black Hole with quasar microlensing

Millon,

Dalang,

Lemon

et al. 2022

Preprint

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We report periodic oscillations in the 15-year long optical light curve of the gravitationally lensed quasar Q J0158−4325 at z s = 1.29. The signal is enhanced during a high magnification microlensing event undergone by the fainter lensed image, B, of the quasar, between 2003 and 2010. We measure a period of P o = 172.6 ± 0.9 days, translating into 75.4 ± 0.4 days in the quasar frame. The oscillations have a maximum amplitude of 0.25 mag, and decrease concurrently with the smooth microlensing amplitude. We explore four scenarios to explain the origin of the periodicity: 1-the high magnification microlensing event is due to a binary star in the lensing galaxy, 2-Q J0158−4325 contains a massive binary black hole system in its final dynamical stage before merging, 3-the quasar accretion disk contains a bright inhomogeneity in Keplerian motion around the black hole, and 4-the accretion disk is in precession. Among these four scenarios, only a binary supermassive black hole can account for both the short observed period and the amplitude of the signal, through the oscillation of the accretion disk towards and away from high-magnification regions of a microlensing caustic. The short measured period implies that the semi-long axis of the orbit is ∼ 10 −3 pc, and the coalescence timescale is t coal ∼ 1000 years, assuming that the decay of the orbit is solely powered by the emission of gravitational waves. The probability of observing a system so close to coalescence, in a sample of only 30 monitored lensed quasars, suggests either a much larger population of supermassive black hole binaries than predicted, or, more likely, that some other mechanism significantly increases the coalescence timescale. Three tests of the binary black hole hypothesis include: i) the recurrence of oscillations in photometric monitoring during any future microlensing events in either image, ii) spectroscopic detection of Doppler shifts (up to ∼0.01c) associated to optical emission in the vicinity of the black holes, and iii) the detection of gravitational waves through Pulsar Timing Array experiments, such as the SKA, which will have the sensitivity to detect the ∼100 nano-hertz emission.

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“…on a timescale of years) are observed in most of the lensed systems and are often used to set constraints on the accretion disk size (see e.g. Morgan et al 2018;, for recent measurements) or on the temperature profile of the disk (Eigenbrod et al 2008;Goicoechea et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Evidence for a milliparsec-separation supermassive binary black hole with quasar microlensing

Millon

Dalang

Lemon

et al. 2022

A&A

View full text Add to dashboard Cite

We report periodic oscillations in the 15-year-long optical light curve of the gravitationally lensed quasar Q J0158−4325 at z s = 1.29. The signal is enhanced during a high magnification microlensing event of the quasar that the fainter lensed image, B, underwent between 2003 and 2010. We measure a period of P o = 172.6 ± 0.9 days, which translates to 75.4 ± 0.4 days in the quasar frame. The oscillations have a maximum amplitude of 0.26 ± 0.02 mag and decrease concurrently with the smooth microlensing amplitude. We explore four scenarios to explain the origin of the periodicity: (1) the high magnification microlensing event is due to a binary star in the lensing galaxy, (2) Q J0158−4325 contains a supermassive binary black hole system in its final dynamical stage before merging, (3) the quasar accretion disk contains a bright inhomogeneity in Keplerian motion around the black hole, and (4) the accretion disk is in precession. Of these four scenarios, only a supermassive binary black hole can account for both the short observed period and the amplitude of the signal, through the oscillation of the accretion disk towards and away from high-magnification regions of a microlensing caustic. The short measured period implies that the semi-major axis of the orbit is ∼ 10 −3 pc and that and the coalescence timescale is t coal ∼ 1000 years, assuming that the decay of the orbit is solely powered by the emission of gravitational waves. The probability of observing a system so close to coalescence, in a sample of only 30 monitored lensed quasars, suggests either a much larger population of supermassive binary black holes than predicted or, more likely, that some other mechanism significantly increases the coalescence timescale. Three tests of the binary black hole hypothesis include: (i) the recurrence of oscillations in photometric monitoring during any future microlensing events in either image, (ii) spectroscopic detection of Doppler shifts (up to ∼ 0.01c) associated with optical emission in the vicinity of the black holes, and (iii) the detection of gravitational waves through pulsar timing array experiments, such as the Square Kilometre Array, which will have the sensitivity to detect the ∼100 nano-hertz emission.Key words. methods: data analysis -gravitational lensing: microlensing -quasars: supermassive black holes 1 To date, OJ 287 is the only confirmed close SMBBH, which was detected from the repeated pairs of outbursts every 12.2 years, interpreted as a secondary black hole crossing the accretion disk of the primary black hole (Valtonen et al. 2008).

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Liverpool-Maidanak monitoring of the Einstein Cross in 2006–2019

Cited by 11 publications

References 51 publications

Geometry and kinematics of the broad emission line region in the lensed quasar Q2237+0305

Geometry and kinematics of the broad emission line region in the lensed quasar Q2237+0305

Evidence for a milliparsec-separation Supermassive Binary Black Hole with quasar microlensing

Evidence for a milliparsec-separation supermassive binary black hole with quasar microlensing

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