The asymmetric compact jet of GRS 1915+105

TL;DR

This study uses VLBA observations to analyze the asymmetric nature of GRS 1915+105's compact jet, estimating flow velocities that are higher than previous measurements but still sub-relativistic, consistent with low/hard state models.

Contribution

First detailed VLBA analysis revealing jet asymmetry and flow velocities in GRS 1915+105 during a plateau state.

Findings

Jet is asymmetric during plateau state

Flow velocity estimated between 0.3 and 0.5c

Results align with low/hard state jet models

Abstract

We present multiepoch VLBA observations of the compact jet of GRS 1915+105 conducted at 15.0 and 8.4 GHz during a {\it plateau} state of the source in 2003 March-April. These observations show that the compact jet is clearly asymmetric. Assuming an intrinsically symmetric continuous jet flow, using Doppler boosting arguments and an angle to the line of sight of $\theta=70\degr$, we obtain values for the velocity of the flow in the range 0.3--0.5$c$. These values are much higher than in previous observations of such compact jet, although much lower than the highly relativistic values found during individual ejection events. These preliminary results are compatible with current ideas on the jet flow velocity for black holes in the low/hard state.