인문학
사회과학
자연과학
공학
의약학
농수해양학
예술체육학
복합학
DBpia AI
AI 에이전트
AI 아이디어
AI 리더
AI 뷰어
Citeasy
크롬 서지관리 다운로드
지원사업
학술연구/단체지원/교육 등 연구자 활동을 지속하도록 DBpia가 지원하고 있어요.
커뮤니티
연구자들이 자신의 연구와 전문성을 널리 알리고, 새로운 협력의 기회를 만들 수 있는 네트워킹 공간이에요.
초록·키워드
Context. Recent studies of the optical depth comparing [ 12 C II ] and [ 13 C II ] line profiles in Galactic star-forming regions have revealed strong self-absorption in [ 12 C II ] by low excitation foreground material. This implies a high column density for C + , corresponding to equivalent A V values of a few (up to about 10) mag. Aims. As the nature and origin of such a great column of cold C + foreground gas are difficult to determine, it is essential to constrain the physical conditions of this material. Methods. We conducted high-resolution observations of [O I ] 63 μm and [O I ] 145 μm lines in M17 SW and Mon R2. The [O I ] 145 μm transition traces warm PDR-material, while the [O I ] 63 μm line traces the foreground material, as manifested by the absorption dips. Results. A comparison of both [O I ] line profiles with [C II ] isotopic lines confirm warm PDR-origin background emission and a significant column of cold foreground material, causing the self-absorption to be visible in the [ 12 C II ] and [O I ] 63 μm profiles. In M17 SW, the C + and O 0 column densities are comparable for both layers. Mon R2 exhibits larger O 0 columns compared to C + , indicating additional material where the carbon is neutral or in molecular form. Small-scale spatial variations in the foreground absorption profiles and the large column density (~10 18 cm −2 ) of the foreground material suggest the emission is coming from high-density regions associated with the cloud complex – and not a uniform diffuse foreground cloud. Conclusions. The analysis confirms that the previously detected intense [C II ] foreground absorption is attributable to a large column of low-excitation dense atomic material, where carbon is ionized and oxygen is in a neutral atomic form.
인공지능 문자 인식 모델을 통해 추출된 텍스트로, 일부 오타나 오류가 포함될 수 있으나 지속적으로 개선 중입니다.
오류를 발견하셨다면 해당 부분을 드래그한 후 ' 를 통해 신고해주세요.
오류를 발견하셨다면 해당 부분을 드래그한 후 ' 를 통해 신고해주세요.
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