Revision of the Properties of the GRS 1915+105 Jets: Clues from the Large‐Scale Structure

The jets of GRS 1915+105 carry a considerable energy away from the centralsource into the ISM. The similarity of the jets of this source and jets inradio galaxies or radio-loud quasars suggests that we should detectlarge-scale, synchrotron emitting radio structures surrounding GRS 1915+105.However, these large structures have not been found. We show that by adapting amodel for the radio lobes of extragalatic jet sources we predict a radiosurface brightness of the equivalent structures of GRS 1915+105 below thecurrent detection limits. The model uses an energy transport rate of the jetsaveraged over the jet lifetime. This transport rate is found to be considerablylower than the power of the jets during the rare major ejection events. Thusthe lobes contain less energy than would be inferred from these events andproduce a lower radio luminosity. The model also predicts a lifetime of thejets of order $10^6$ years and a gas density of the ISM in the vicinity of GRS1915+105 of $\sim 150$ cm$^{-3}$. The impact sites of the jets are identifiedwith two {\sc iras} regions with a flat radio spectrum located on either sideof GRS 1915+105. Observations of molecular lines and dust emission from theseobjects are consistent with our interpretation. Distance estimates for the {\sciras} regions give 6.5 kpc and our model implies that this is also the distanceto GRS 1915+105. This low distance estimate in combination with the observedmotions of jet ejections on small scales yields a jet velocity of about 0.7 cand an angle of $53^{\circ}$ of the jets to our line of sight.Comment: replaced with shorter (10 pages) emulateapj versio