The Molecular Medium of H1413+117: BIMA CO (3–2) and HCO[TSUP]+[/TSUP] (4–3) Observations
1995; IOP Publishing; Volume: 453; Issue: 2 Linguagem: Inglês
10.1086/309756
ISSN1538-4357
AutoresDavid J. Wilner, Jun‐Hui Zhao, Paul T. P. Ho,
Tópico(s)Astrophysical Phenomena and Observations
ResumoWe report observations of the CO (3-2) and HCO+ (4-3) lines toward H1413+117, the z = 2.56 "cloverleaf" quasar, obtained simultaneously with the BIMA. These observations, with beam size 28 × 24, confirm the CO (3-2) emission redshifted to 3 mm wavelength observed at lower resolution by Barvainis and coworkers. We find an upper limit to the HCO+ (4-3)/CO (3-2) intensity ratio of 0.33. This suggests that the mean density of the molecular gas, averaged over the beam, is lower than the 107 cm-3 "critical density" of the HCO+ (4-3) line for collisional excitation. The implications of this limit depend primarily on the size scale probed by the observations. The physical conditions appear generally consistent with an average over molecular complexes in the central kiloparsecs of nearby starburst galaxies but may differ from those in the inner 300 pc of NGC 1068, the active nucleus with the best studied molecular medium.
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