On the Detectability of Dual Jets From Binary Black Holes

Abstract

We revisit the suggestion that dual jets can be produced during the inspiral and merger of supermassive black holes when these are immersed in a force-free plasma threaded by a uniform magnetic field. By performing independent calculations of the late inspiral and merger, and by computing the electromagnetic (EM) emission in a way which is consistent with estimates using the Poynting flux, we show that a dual-jet structure is present but energetically subdominant with respect to a non-collimated and predominantly quadrupolar emission, which is similar to the one computed when the binary is in electrovacuum. While our findings set serious restrictions on the detectability of dual jets from coalescing binaries, they also increase the chances of detecting an EM counterpart from these systems.

Plasma-Wave Generation in a Dynamic Spacetime

“…This is consistent with the numerical observations of Neilsen et al (2011) and Moesta et al (2012) (see the top-right corner of Figure 1). On the other hand, we caution that our computations do not take into account nonlinearities, so the analytical fit to numerical data should be interpreted with a pinch of salt.…”

“…Therefore, with a large extraction radius and when the black hole separation is large, the numerical cone would likely enclose a fair amount of fast-magnetosonic waves, contributing to the relative weakness of numerically measured isotropic flux. Many other numerical difficulties associated with subtracting off a background radiation in order to construct a division of the overall flux into the collimated and isotropic types, especially when the overall flux is weak, have been discussed in the numerical papers such as Neilsen et al (2011) and Moesta et al (2012). We refer interested readers to these important literature.…”

“…Thanks to the seminal works by Goldreich & Julian (1969) and Blandford & Znajek (1977), it is widely accepted that force-free plasma can act as a medium for powering outgoing EM radiation (or jets) at a cost of reducing the rotational energy of neutrons stars or black holes (Thorne 1994;Spruit et al 1997;Palenzuela et al 2011;Hansen & Lyutikov 2001;Meier 2012). More recent studies (Hansen & Lyutikov 2001;Palenzuela et al 2009Palenzuela et al , 2010aPalenzuela et al , 2010bPalenzuela et al , 2010cLyutikov 2011;McWilliams & Levin 2011;Neilsen et al 2011;Alic et al 2012;Moesta et al 2012;DOrazio & Levin 2013;Morozova et al 2014;Penna 2015) suggest that a force-free plasma could also drain the (linear-motion) kinetic energy of moving objects to power EM radiations in the form of jets launching from star surfaces (or the black hole horizon), accompanied by some isotropic flux. We refer to this as the kinetic-motion-driven radiation, 5 which is also seen from satellites moving in earthʼs ionosphere (Drell et al 1965a(Drell et al , 1965b.…”

Electromagnetic partner of the gravitational signal during accretion onto black holes

“…Concerning black hole spacetimes, the dynamics of black holes immersed in a magnetic field was considered for example in [5][6][7][8]. In [9], a study of the coupling of axial gravitational and electromagnetic perturbations for black holes and neutron stars was performed.…”

Numerical Relativity in Higher Dimensions

“…NR studies have furthermore provided valuable insight into a variety of astrophysical scenarios involving BHs as for example the study of gravitational recoil, [17][18][19][20] jet phenomena 21,22 and electromagnetic counterparts for multi-messenger astrophysics. [23][24][25][26][27][28] For reviews of these subjects we refer to Refs. 29, 30, 31, 32, 33. In recent years, however, NR has also emerged as a valuable tool to explore highenergy physics scenarios.…”