New radio lobes at parsec scale from the east–west protostellar jet RAFGL2591

Abstract

ABSTRACT RAFGL2591 is a massive star-forming complex in the Cygnus-X region comprising of a cluster of embedded protostars and young stellar objects located at a distance of 3.33 kpc. We investigate low-frequency radio emission from the protostellar jet associated with RAFGL2591 using the Giant Metrewave Radio Telescope (GMRT) at 325, 610, and 1280 MHz. For the first time, we have detected radio jet lobes in the east–west direction, labelled as GMRT-1 and GMRT-2. While GMRT-1 displays a flat radio spectral index of α = −0.10, GMRT-2 shows a steeply negative value of α = −0.62 suggestive of non-thermal emission. H2 emission maps show the presence of numerous knots, arcs, and extended emission towards the east–west jet, excited by the protostar VLA 3. In addition, we report a few H2 knots in the north-east and south-west for the first time. The radio lobes (GMRT-1 and GMRT-2) and H2 emission towards this region are understood in the context of the prominent east–west jet as well as its lesser-known sibling jet in the north-east and south-west direction. To model the radio emission from the lobes, we have employed a numerical model including both thermal and non-thermal emission and found number densities towards these lobes in the range 100–1000 cm−3. The misalignment of the east–west jet lobes exhibits a reflection symmetry with a bending of ∼20°. We attempt to understand this misalignment through precession caused by a binary partner and/or a supersonic side wind from source(s) in the vicinity.