CO observations of gas near the galactic supernova remnants G5.4-1.2, G5.55+0.32 and G5.71-0.08 ^*,**

National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475, USA e-mail: hliszt@nrao.edu

Received: 4 May 2009
Accepted: 13 October 2009

Abstract

Aims. We searched for signs of interaction of radio supernova remnants with ambient molecular gas in the sky field just West of the SNR W28.

Methods. We analyze a datacube of CO emission having 1′ and 1.2 km s^-1 resolution, made with on-the-fly mapping over the region ^o.

Results. Although broad CO lines characteristic of shocked gas were not seen in this kinematically complex region, a bright (14 K), new, marginally-resolved  km s^-1 outflow source G5.638+0.233 and a comparably bright rim of CO emission were found at/around the periphery of SNR G5.55+0.12. Most of the periphery of SNR G5.71-0.08 is surrounded by a bright rim of CO emission. CO emission at the 7 km s^-1 velocity of a 1720 OH maser spot near SNR G5.70-0.12 is very bright, 19 K, but gas at -21 km s^-1 is widespread over the region and CO emission is rather weak toward the OH maser spots at this velocity north of G5.4-1.2. Other very bright CO lines in the region are associated with H II regions, i.e. 27 K toward W28A2 = G5.89-0.39 and 15 K toward an MSX-IR source at ^o, ^o which is probably the exciting agent of a separate, classical HII region just north of W28A2.