BRAINE, J.; FERGUSON, Annette M. N.; BERTOLDI, Frank; WILSON, Christine D.

doi:10.1086/524135

Metadatos

Licencia de uso del documento

BRAINE, J.
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Observatoire aquitain des sciences de l'univers [OASU]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]

FERGUSON, Annette M. N.
Department of Physics

BERTOLDI, Frank

Idioma

Article de revue

Este ítem está publicado en

The Astrophysical Journal. 2007, vol. 669, n° 2, p. L73-L76

American Astronomical Society

Resumen en inglés

We present the results of a search for molecular gas emission via the CO line in the far outer disk of the nearby spiral, NGC 6946. The positions targeted were chosen to lie on or near previously-identified outer disk HII regions. Molecular gas was clearly detected out to 1.3 R$_{25}$, with a further tentative detection at 1.4 R$_{25}$. The CO detections show excellent agreement with the HI velocities and imply beam-averaged column densities of $0.3-9\times 10^{20}$ cm$^{-2}$ and molecular gas masses of (2-70)$\times 10^{5}$ M$_{\sun}$ per 21$''$ beam (560pc). We find evidence for an abrupt decrease in the molecular fraction at the edge of the optical disk, similar to that seen previously in the azimuthally-averaged areal star formation rate. Our observations provide new constraints on the factors that determine the presence and detectability of molecular gas in the outskirts of galaxies, and suggest that neither the HI column, the metallicity or the local heating rate alone plays a dominant role.< Leer menos

Palabras clave en inglés

galaxies: individual (NGC 6946)—galaxies: individual (NGC 1058) — galaxies: spiral — galaxies: ISM

ISM: molecules

radio lines: ISM

Metadatos

Licencia de uso del documento

The Detection of Molecular Gas in the Outskirts of NGC 6946

Idioma

Este ítem está publicado en

Resumen en inglés

Palabras clave en inglés

DOI

Orígen

Centros de investigación