2008MNRAS.391L..54T

We obtain new Hi and ¹³CO images around supernova remnants Kes 69 and G21.5-0.9. By comparing Hi spectra with ¹³CO emission spectra, we significantly revise the kinematic distance for Kes 69 to ∼5.5 kpc, which was 11.2 kpc, and refine the kinematic distance for G21.5-0.9 to ∼4.8 kpc. For Kes 69, the highest velocity of absorption is ∼86 km/s and a prominent Hi emission feature at ∼112 km/s has no respective absorption. These new results suggest that Kes 69 is associated with a newly detected extended 1720-MHz OH maser at velocity of ∼85 km/s that originates from within the bright southern radio shell of Kes 69. For G21.5-0.9, the highest velocity of absorption is ∼67 km/s. The Hi absorption spectra of the nearby bright source PMN J1832-1035 and Kes 69 show a common absorption feature at velocity of ∼69 km/s, which is not seen for G21.5-0.9. The resulting velocity of ∼68 km/s gives the best distance estimate of ∼4.8 kpc for G21.5-0.9 and associated young pulsar J1833-1034.