Detection of interstellar C2 and C3 in the Small Magellanic Cloud
Artikel i vetenskaplig tidskrift, 2013

We report the detection of absorption from interstellar C2 and C3 towards the moderately reddened star Sk 143, located in the near `wing' region of the SMC, in optical spectra obtained with the European Southern Observatory Very Large Telescope (VLT)/Ultraviolet and Visual Echelle Spectrograph. These detections of C2 (rotational levels J = 0-8) and C3 (J = 0-12) absorption in the SMC are the first beyond our Galaxy. The total abundances of C2 and C3 (relative to H2) are similar to those found in diffuse Galactic molecular clouds - as previously found for CH and CN - despite the significantly lower average metallicity of the Small Magellanic Cloud. Analysis of the rotational excitation of C2 yields an estimated kinetic temperature Tk ˜ 25 K and a moderately high total hydrogen density nH ˜ 870 cm-3 - compared to the T01 ˜ 45 K and nH ˜ 85-300 cm-3 obtained from H2. The populations of the lower rotational levels of C3 are consistent with an excitation temperature of about 34 K.

galaxies: Interstellar matter

Interstellar matter: molecules

Magellanic Clouds

Interstellar matter: lines and bands

Författare

Daniel E. Welty

University of Chicago

J. Christopher Howk

University of Notre Dame

Nicolas Lehner

University of Notre Dame

John H Black

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 428 1107-1115

Ämneskategorier

Astronomi, astrofysik och kosmologi

Fundament

Grundläggande vetenskaper

Infrastruktur

Onsala rymdobservatorium

DOI

10.1093/mnras/sts093