A 12CO ($J=1\rightarrow 0$) and ($J=2\rightarrow 1$) atlas of circumstellar envelopes of AGB and post-AGB stars

We present the results of a 12CO () and () survey on a sample of 46 objects classified as AGB and post-AGB stars. We have obtained fully sampled high resolution maps of their 12CO () emission by combining visibilities from the IRAM interferometer with short spacing observations from the IRAM 30 m telescope. Properties of their circumstellar envelopes like fluxes, radii, and positions are derived from model fits to the visibilities and compared to the results obtained from 12CO () maps observed at the IRAM 30 m telescope. From the 12CO () observations we have derived mass loss rates for 38 stars and established an empirical relation between the CO photodissociation radius of an envelope and the measured radius in the () emission.