Relativistic motion in a nearby bright X-ray source
journal contribution
posted on 2023-05-16, 10:08authored byTingay, SJ, Jauncey, DL, Preston, RA, Reynolds, JE, Meier, DL, Murphy, DW, Tzioumis, AK, McKay, DJ, Kesteven, MJ, James LovellJames Lovell, Campbell-Wilson, D, Simon EllingsenSimon Ellingsen, Gough, R, Hunstead, RW, Jones, DL, Peter McCullochPeter McCulloch, Migenes, V, Quick, J, Sinclair, MW, Smits, D
The recent discovery of radio components apparently moving away from a Galactic source of transient X-ray emission faster than the speed of light (superluminal motion) has identified a low-energy Galactic counterpart to quasars. Here we report high-resolution radio observations of a second Galactic superluminal radio source GRO J1655-40, which was detected as an X-ray transient on 27 July 1994. Our radio images reveal two components moving away from each other at an angular speed of 65 ± 5 mas d-1, corresponding to superluminal motion at the estimated distance of 3–5 kpc. The 12-day delay between the X-ray and radio outbursts suggests that the ejection of material at relativistic speeds occurs during a stable phase of accretion onto a black hole, which follows an unstable phase with a high accretion rate.