G19A001

Confirming the first detection of a merging dual SMBH system at high-z

Abstract

We have recently detected the first example of proper motion in a candidate binary black hole
system at z ~ 3 through high resolution radio imaging with the VLBA at 1.7 GHz and by using
the magnification provided by a gravitational lens. We find that the two radio-loud black holes
are moving towards each other, with a current projected distance of just ~175 pc. Here, we
request sensitive global VLBI observations at 5 GHz to i) make a higher precision
measurement of the proper motion of the radio components and ii) test the lensing mass
model for the system. These observations will robustly confirm the binary black hole
hypothesis and test dynamical models for this system.

Investigators

Name	Institution
John McKean	Netherlands Institute for Radio Astronomy; Kapteyn Astronomical Institute
Davide Massari	Kapteyn Astronomical Institute
Cristiana Spingola *	Kapteyn Astronomical Institute; Istituto Nazionale di Astrofisica; Bologna, Università degli Studi di
GBT Operator	Green Bank Observatory

* indicates the PI