SIMBAD references

A search for infrared ring nebulae associated with regions of ionized hydrogen has been carried out. The New GPS Very Large Array survey at 20cm forms the basis of the search, together with observations obtained with the Spitzer Space Telescope at 8 and 24µm and the Herschel Space Telescope at 70µm. Objects having ring-like morphologies at 8µm and displaying extended emission at 20 cm were selected visually. Emission at 24µm having the form of an inner ring or central peak is also observed in the selected objects. A catalog of 99 ring nebulae whose shapes at 8 and 70µm are well approximated by ellipses has been compiled. The catalog contains 32 objects whose shapes are close to circular (eccentricities of the fitted ellipses at 8 µm no greater than 0.6, angular radius exceeding 20''). These objects are promising for comparisons with the results of one-dimensional hydrodynamical simulations of expanding regions of ionized hydrogen.