Measuring black hole spin in OJ287

Valtonen, M. J.; Mikkola, Seppo; Lehto, H. J.; Hyvönen, T.; Nilsson, K.; Merritt, David; Gopakumar, A.; Rampadarath, H.; Hudec, R.; Bašta, Milan; Saunders, Richard D. E.

doi:10.1007/s10569-009-9252-z

Cited by 22 publications

(34 citation statements)

References 31 publications

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“…Thus we take observations from the historical light curve (see e.g. Valtonen et al 2010b) and remove the well‐known outburst peaks. The resulting base level light curve is shown in Fig.…”

Section: The Jetmentioning

confidence: 99%

Optical polarization angle and VLBI jet direction in the binary black hole model of OJ287

Valtonen¹,

Wiik²

2012

Monthly Notices of the Royal Astronomical Society

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We study the variation of the optical polarization angle in the blazar OJ287 and compare it with the precessing binary black hole model with a ‘live’ accretion disc. First, a model of the variation of the jet direction is calculated, and the main parameters of the model are fixed by the long‐term optical brightness evolution. Then this model is compared with the variation of the parsec‐scale radio jet position angle in the sky. Finally, the variation of the polarization angle is calculated using the same model, but using a magnetic field configuration which is at a constant angle relative to the optical jet. It is found that the model fits the data reasonably well if the field is almost parallel to the jet axis. This may imply a steady magnetic field geometry, such as a large‐scale helical field.

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“…Thus we take observations from the historical light curve (see e.g. Valtonen et al 2010b) and remove the well‐known outburst peaks. The resulting base level light curve is shown in Fig.…”

Section: The Jetmentioning

confidence: 99%

Optical polarization angle and VLBI jet direction in the binary black hole model of OJ287

Valtonen¹,

Wiik²

2012

Monthly Notices of the Royal Astronomical Society

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“…The test relies on the argument that a bright emission ring characterizing the flow image will be elliptical and asymmetric if the theorems are violated (Broderick et al 2013). Finally, quasiperiodic oscillations, relativistically broadened iron lines, continuum spectrum and X-ray polarization in the accretion disk surrounding a spinning black hole may also be used as a probe of the no-hair theorems (Johannsen and Psaltis 2010a, 2010b, Bambi and Barausse 2011a, 2011b, Bambi 2012a, 2012c, Krawczynski 2012.…”

Section: Strong Limit: Spinning Black Holes and No-hair Theoremmentioning

confidence: 99%

“…Thus here we are carrying out strong field tests of General Relativity. For example, it has been shown that the loss of orbital energy from the system agrees with General Relativity with the accuracy of 2% (Valtonen et al 2010b). More importatly, we may test the no hair theorems of black holes (Israel 1967, 1968, Carter 1970, Hawking 1971, 1972, see also Misner, Thorne and Wheeler 1973) for the first time.…”

Section: Introductionmentioning

confidence: 95%

Observations of General Relativity at strong and weak limits

Byrd¹,

Chernin²,

Teerikorpi³

et al. 2015

General Relativity: The Most Beautiful of Theories

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Einstein's General Relativity theory has been tested in many ways during the last hundred years as reviewed in this chapter. Two tests are discussed in detail in this article: the concept of a zero gravity surface, the roots of which go back to Järnefelt, Einstein and Straus, and the no-hair theorem of black holes, first proposed by Israel, Carter and Hawking. The former tests the necessity of the cosmological constant Λ, the latter the concept of a spinning black hole. The zero gravity surface is manifested most prominently in the motions of dwarf galaxies around the Local Group of galaxies. The no-hair theorem is testable for the first time in the binary black hole system OJ287. These represent stringent tests at the limit of weak and strong gravitational fields, respectively. In this article we discuss the current observational situation and future possibilities.

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“…However, building a template bank with spin effects may be crucial to optimizing the detection rate in these searches. Electromagnetic observations of BHs in X-ray binaries [36][37][38][39][40][41][42], as well as population synthesis models for BBH formation [43], indicate the potential for a range of BH spins, possibly spanning the entire theoretically-allowed range given by the Kerr limit |cS/Gm 2 | ≤ 1, where S is the spin angular momentum of the BH and m is its mass. These spin effects are apparent in the waveform templates, and using non-spinning templates to search for spinning signals is sub-optimal, as we quantify below.…”

Section: Introductionmentioning

confidence: 99%

Implementing a search for gravitational waves from binary black holes with nonprecessing spin

et al. 2016

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Searching for gravitational waves (GWs) from binary black holes (BBHs) with LIGO and Virgo involves matched-filtering data against a set of representative signal waveforms -a template bankchosen to cover the full signal space of interest with as few template waveforms as possible. Although the component black holes may have significant angular momenta (spin), previous searches for BBHs have filtered LIGO and Virgo data using only waveforms where both component spins are zero. This leads to a loss of signal-to-noise ratio for signals where this is not the case. Combining the best available template placement techniques and waveform models, we construct a template bank of GW signals from BBHs with component spins χ1,2 ∈ [−0.99, 0.99] aligned with the orbital angular momentum, component masses m1,2 ∈ [2, 48] M , and total mass M total ≤ 50 M . Using effectiveone-body waveforms with spin effects, we show that less than 3% of the maximum signal-to-noise ratio (SNR) of these signals is lost due to the discreetness of the bank, using the early advanced LIGO noise curve. We use simulated advanced LIGO noise to compare the sensitivity of this bank to a non-spinning bank covering the same parameter space. In doing so, we consider the competing effects between improved SNR and signal-based vetoes, and the increase in the rate of false alarms of the aligned-spin bank due to covering a larger parameter space. We find that the aligned-spin bank can be a factor of 1.3 -5 more sensitive than a non-spinning bank to BBHs with dimensionless spins > +0.6 and component masses 20 M . Even larger gains are obtained for systems with equally high spins but smaller component masses.

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Measuring black hole spin in OJ287

Cited by 22 publications

References 31 publications

Optical polarization angle and VLBI jet direction in the binary black hole model of OJ287

Optical polarization angle and VLBI jet direction in the binary black hole model of OJ287

Observations of General Relativity at strong and weak limits

Implementing a search for gravitational waves from binary black holes with nonprecessing spin

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