A massive binary black-hole system in OJ 287 and a test of general relativity

Valtonen, M. J.; Lehto, H. J.; Nilsson, K.; Heidt, J.; Takalo, L. O.; Sillanpää, A.; Villforth, C.; Kidger, M.; Poyner, G.; Pursimo, T.; Zoła, S.; Wu, Ji; Zhou, Xu; Sadakane, Kozo; Dróżdż, M.; Kozieł, D.; Marchev, D.; Ogłoza, W.; Porowski, C.; Siwak, M.; Stachowski, G.; Winiarski, M.; Hentunen, V. P.; Nissinen, M.; Liakos, A.; Doğru, S.

doi:10.1038/nature06896

Cited by 376 publications

(360 citation statements)

References 23 publications

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“…The observed light curve of Sharov 21 is roughly fitted by either of the two scenarios, but more detailed modelling is necessary to decide if the flare can be reproduced accurately. Finally, we cannot exclude that the flare is part of a quasi-periodic activity similar to OJ 287 (Valtonen et al 2008) on an intrinsic time scale of > ∼ 10 yr. The remarkable quasar Sharov 21 obviously merits further efforts, both for the completion of the light curve and for its modelling.…”

Section: Discussionmentioning

confidence: 99%

J004457+4123 (Sharov 21): not a remarkable nova in M 31 but a background quasar with a spectacular UV flare

Meusinger¹,

Henze

Birkle

et al. 2010

A&A

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Aims. We announce the discovery of a quasar behind the disk of M 31, which was previously classified as a remarkable nova in our neighbour galaxy. It is shown here to be a quasar with a single strong flare where the UV flux has increased by a factor of ∼20. The present paper is primarily aimed at the remarkable outburst of J004457+4123 (Sharov 21), with the first part focussed on the optical spectroscopy and the improvement in the photometric database. Methods. We exploited the archives of photographic plates and CCD observations from 15 wide-field telescopes and performed targetted new observations. In the second part, we try to fit the flare by models of (1) gravitational microlensing due to a star in M 31 and (2) a tidal disruption event (TDE) of a star close to the supermassive black hole of the quasar. Results. Both the optical spectrum and the broad band spectral energy distribution of Sharov 21 are shown to be very similar to that of normal, radio-quiet type 1 quasars. We present photometric data covering more than a century and resulting in a long-term light curve that is densely sampled over the past five decades. The variability of the quasar is characterized by a ground state with typical fluctuation amplitudes of ∼0.2 mag aroundB ∼ 20.5, superimposed by a singular flare of ∼2 yr duration (observer frame) with the maximum at 1992.81. The total energy in the flare is at least three orders of magnitudes higher than the radiated energy of the most luminous supernovae, provided that it comes from an intrinsic process and the energy is radiated isotropically. The profile of the flare light curve is asymmetric showing in particular a sudden increase before the maximum, whereas the decreasing part can be roughly approximated by a t −5/3 power law. Both properties appear to support the standard TDE scenario where a ∼10 M giant star was shredded in the tidal field of a ∼2 . . . 5 × 10 8 M black hole. The short fallback time derived from the observed light curve requires an ultra-close encounter where the pericentre of the stellar orbit is deep within the tidal disruption radius. This simple model neglects, however, the influence of the massive accretion disk, as well as general-relativistic effects on the orbit of the tidal debris. Gravitational microlensing probably provides an alternative explanation, although the probability of such a high amplification event is very low.

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Section: Discussionmentioning

confidence: 99%

J004457+4123 (Sharov 21): not a remarkable nova in M 31 but a background quasar with a spectacular UV flare

Meusinger¹,

Henze

Birkle

et al. 2010

A&A

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“…A simple estimate of the fraction of quasars that would harbour binaries with an orbital period t bin can be obtained from the residence time tres = a/ȧ at each separation a, and the lifetime of bright (LQ/L edd ∼ > 1 Note that in the precessing binary model for OJ287 (Lehto & Valtonen 1996;Valtonen et al 2008), the orbital period is 12.2 yr, the primary is very massive (∼ 1.8×10 10 M ), but the secondary is light (∼ 1.4×10 8 M ). The latter reduces the efficiency of GWs, but increases the impact of a gas disc; as a result, the OJ287 binary is gas-driven, well before decoupling.…”

Section: Binary Fraction Among Quasarsmentioning

confidence: 99%

A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?

D’Orazio

Haiman

Duffell

et al. 2015

Mon. Not. R. Astron. Soc.

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Graham et al. have detected a 5.2 yr periodic optical variability of the quasar PG 1302-102 at redshift z = 0.3, which they interpret as the redshifted orbital period (1 + z)t bin of a putative supermassive black hole binary (SMBHB). Here, we consider the implications of a 3 − 8 times shorter orbital period, suggested by hydrodynamical simulations of circumbinary discs (CBDs) with nearly equal-mass SMBHBsWith the corresponding 2−4 times tighter binary separation, PG 1302 would be undergoing gravitational wave dominated inspiral, and serve as a proof that the BHs can be fuelled and produce bright emission even in this late stage of the merger. The expected fraction of binaries with the shorter t bin , among bright quasars, would be reduced by one to two orders of magnitude, compared to the 5.2 yr period, in better agreement with the rarity of candidates reported by Graham et al. Finally, shorter periods would imply higher binary speeds, possibly imprinting periodicity on the light curves from relativistic beaming, as well as measurable relativistic effects on the Fe K α line. The CBD model predicts additional periodic variability on time-scales of t bin and ≈ 0.5t bin , as well as periodic variation of broad line widths and offsets relative to the narrow lines, which are consistent with the observations. Future observations will be able to test these predictions and hence the binary+CBD hypothesis for PG 1302.

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“…OJ 287 shows a periodical behaviour in its optical emission. Analysing its historical light-curve, several studies concluded that it shows a period of ∼12 years (Sillanpaa et al 1988(Sillanpaa et al , 1996, explained by a binary black hole system (Sillanpaa et al 1988;Valtaoja et al 2000;Valtonen et al 2008). Variability has also been detected both at radio and X-ray wavelengths Hughes et al 1998;Hovatta et al 2008).…”

Section: Resultsmentioning

confidence: 99%

Optical flux behaviour of a sample ofFermiblazars

Marchesini

Andruchow

Cellone

et al. 2016

A&A

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Aims. We aim at investigating the time-behaviour of a sample of gamma-ray blazars. We present the results from a 13 monthlong optical photometry monitoring campaign of the blazars PKS 0048−097, PKS 0754+100, [HB89] 0827+243, PKS 0851+202, PKS 1253−055, PKS 1510−089, PKS 1749+096, PKS 2230+114 and PKS 2251+158. Methods. We analyse the variability of each object, focusing on different time-scales (long term, short term, and microvariability), in an attempt to achieve a statistical comparison of the results. Results. After applying a geometric model to explain the variability results, we found that it is possible that a slight change in the direction of the jet generates the variations detected in some objects during this campaign.

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A massive binary black-hole system in OJ 287 and a test of general relativity

Cited by 376 publications

References 23 publications

J004457+4123 (Sharov 21): not a remarkable nova in M 31 but a background quasar with a spectacular UV flare

J004457+4123 (Sharov 21): not a remarkable nova in M 31 but a background quasar with a spectacular UV flare

A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?

Optical flux behaviour of a sample ofFermiblazars

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