Infrared Morphology of Regions of Ionized Hydrogen

TL;DR

This study identifies and catalogs 99 infrared ring nebulae associated with ionized hydrogen regions using multi-wavelength observations, providing a valuable resource for testing hydrodynamical models of such regions.

Contribution

It presents the first comprehensive catalog of infrared ring nebulae with well-defined elliptical shapes, including a subset suitable for hydrodynamical simulation comparisons.

Findings

Catalog of 99 ring nebulae with elliptical shapes

32 objects with near-circular shapes suitable for modeling

Multi-wavelength observations reveal consistent ring morphologies

Abstract

A search for infrared ring nebulae associated with regions of ionized hydrogen has been carried out. The New GPS Very Large Array survey at 20 cm forms the basis of the search, together with observations obtained with the Spitzer Space Telescope at 8 and 24 $\mu$m and the Herschel Space Telescope at 70 $\mu$m. Objects having ring-like morphologies at 8 $\mu$m and displaying extended emission at 20 cm were selected visually. Emission at 24 $\mu$m 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 70 $\mu$m 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 $\mu$m 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.