We have observed the HI distribution in an area 40 x 40 around the neutron star candidate RX J0822-4300, which is located in the supernova remnant Puppis A. The observations of the 21 cm line were obtained with the Australia Telescope Compact Array (ATCA) and were combined with single dish data from the Southern Galactic Plane Survey. The spatial resolution is 90, and the velocity resolution, 1 km/s . A sensitivity of ~ 0.7 K was achieved. The results revealed a double lobed feature of reduced emission at +16 km/s, centered on the central compact object (CCO), and aligned with an HI hole blueshifted by 13 km/s. The HI depressions have probably been created by the sweeping up of ~ 2 solar masses. The alignement between the lobes and the optical expansion centre of Puppis A suggests that the CCO could be ejecting two opposite jets. The velocity at which the two lobes are best defined allowed us to confirm that the distance to Puppis A is 2.2 kpc, based on a systemic velocity of +16 km/s. The hydrogen column density computed using this systemic velocity is consistent with estimates from models for X-ray spectra, thus reinforcing our conclusion that the kinematic distance is 2.2 k pc.
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