A Displaced Supermassive Black Hole in M87

Abstract

Isophotal analysis of M87, using data from the Advanced Camera for Surveys, reveals a projected displacement of 6.8 ± 0.8 pc (∼ 0. ′′ 1) between the nuclear point source (presumed to be the location of the supermassive black hole, SMBH) and the photo-center of the galaxy. The displacement is along a position angle of 307 ± 17 • and is consistent with the jet axis. This suggests the active SMBH in M87 does not currently reside at the galaxy center of mass, but is displaced in the counter-jet direction. Possible explanations for the displacement include orbital motion of an SMBH binary, gravitational perturbations due to massive objects (e.g., globular clusters), acceleration by an asymmetric or intrinsically one-sided jet, and gravitational recoil resulting from the coalescence of an SMBH binary. The displacement direction favors the latter two mechanisms. However, jet asymmetry is only viable, at the observed accretion rate, for a jet age of >0.1 Gyr and if the galaxy restoring force is negligible. This could be the case in the low density core of M87. A moderate recoil ∼1 Myr ago might explain the disturbed nature of the nuclear gas disk, could be aligned with the jet axis, and can produce the observed offset. Alternatively, the displacement could be due to residual oscillations resulting from a large recoil that occurred in the aftermath of a major merger ≤1 Gyr ago.

Post-Newtonian Dynamical Modeling of Supermassive Black Holes in Galactic-scale Simulations

“…Finally, the accurate dynamical modeling of the SMBHs could shed light on the possible offsets between the central SMBH and the hosting dark matter halo, which will be important for experiments that attempt a direct detection of the possible central dark matter annihilation signal (e.g. Batcheldor et al 2010;Lacroix et al 2014). SMBH binaries can also change the stellar dynamics of the nuclear regions of the host galaxy, which can be now probed with integral field unit (IFU) observations (Thomas et al 2016).…”

Prompt electromagnetic transients from binary black hole mergers

“…A number of mechanisms may provide signals associated with these sources across a broad range of time scales from ∼10 9 years before merger to ∼10 9 years after merger [13]. Considerable evidence for binary SMBH systems has already been observed, but is restricted to those either well before merger [14][15][16][17][18][19][20][21], or well after merger [22][23][24][25][26][27][28].…”

Eötvös experiments with supermassive black holes

“…The slices of the annulus along the direction of the observed jet and potential counterjet are omitted from the calculation and so exclude light from the AGN itself. This technique contrasts with that of Batcheldor et al (2010). They explicitly masked the noticeable jet emission as well as globular clusters.…”

“…However, subsequently neither Gebhardt et al (2011) Gebhardt et al (2011). Batcheldor et al (2010) outlined several astrophysical explanations for a potential displacement such as a SMBH binary, a recent merging of black holes or a one-sided jet. The interaction with the neighbouring stars or even clusters of stars is too weak to explain such a displacement.…”