Spatial Variation of PAH Ionization in the Orion Nebula

Kentaro Haraguchi, Takahiro Nagayama, Mikio Kurita, Masaru Kino, Shuji Sato

doi:10.1093/pasj/64.6.127

<jats:p>We have carried out near-infrared imaging observations of the Orion Nebula with Wide Field Cryogenic Telescope-II. The observations covered a 1$^{\circ}$$\times$ 1$^{\circ}$ area with a resolution of 12$''$ through two narrow-band filters at 3.3 $\mu $ m, tuned to the C–H band and 3.7 $\mu $ m off-the-band emissions of PAHs. We detected diffuse emissions extending larger than 10$'$ from the Trapezium cluster in both filters. We extracted the fluxes of the 3.3 $\mu $ m band emission (${F}_{\rm band}$ ) and of the 3.7 $\mu $ m continuum emission (${F}_{\rm cont}$ ) from the 3.3 $\mu $ m and 3.7 $\mu $ m filter data, respectively. The ${F}_{\rm band}$ and ${F}_{\rm cont}$ maps have similar extension over a 10$'$$\times$ 10$'$ area centered on the Trapezium cluster. Although an overall morphological resemblance can be seen between the ${F}_{\rm band}$ and ${F}_{\rm cont}$ maps, the ratio ${F}_{\rm band}/{F}_{\rm cont}$ varies from region to region in the area. The variation of ${F}_{\rm band}/{F}_{\rm cont}$ is attributed to differences of the PAH ionization degree. Adopting emissivities of neutral and ionized PAHs, we calculated the PAH ionization degrees, and constructed a PAH ionization map in the Orion Nebula. The ionization degree varies significantly from region to region in the Orion Nebula, being $\sim$ 50% at the photo-dissociation regions of the Orion Bar, and less ionized at both sides. This partial ionization revealed based on near-infrared observations is consistent with the ionization states estimated from recent mid-infrared observations.</jats:p>

Spatial Variation of PAH Ionization in the Orion Nebula

この論文をさがす

説明

収録刊行物

被引用文献 (2)*注記

詳細情報詳細情報について

書き出し

問題の指摘

Spatial Variation of PAH Ionization in the Orion Nebula

この論文をさがす

説明

収録刊行物

被引用文献 (2)*注記

詳細情報 詳細情報について

書き出し

問題の指摘

詳細情報詳細情報について