Detection of CI in absorption towards PKS 1830-211 with the eSMA

Abstract

We report the first science observations and results obtained with the "extended" SMA (eSMA), which is composed of the SMA (Submillimeter Array), JCMT (James Clerk Maxwell Telescope) and CSO (Caltech Submillimeter Observatory). Redshifted absorptions at z=0.886 of CI (^3P_1 - ^3P_0) were observed with the eSMA with an angular resolution of 0.55"x0.22" at 1.1 mm toward the southwestern image of the remarkable lensed quasar PKS 1830-211, but not toward the northeastern component at a separation of ~1". Additionally, SMA observations of CO, 13CO and C18O (all J=4-3) were obtained toward this object: CO was also detected toward the SW component, but none of the isotopologues were. This is the first time [CI] is detected in this object, allowing the first direct determination of relative abundances of neutral atomic carbon to CO in the molecular clouds of a spiral galaxy at z>0.1. The [CI] and CO profiles can be decomposed into two and three velocity components respectively. We derive C/CO column density ratios ranging from <0.5 (representative of dense cores) to ~2.5 (close to translucent clouds values). This could indicate that we are seeing environments with different physical conditions or that we are witnessing chemical evolution of regions where C has not completely been converted into CO.

6 pages using emulateapj, 3 tables, 2 figures ; accepted for publication in ApJL

References in corpus (7)

• A computer program for fast non-LTE analysis of interstellar line spectra
• First detection of CO in a high-redshift DLA
• Probing isotopic ratios at z = 0.89: molecular line absorption in front of the quasar PKS 1830-211
• Drastic changes in the molecular absorption at redshift z=0.89 toward the quasar PKS 1830-211
• The kinetic temperature of a molecular cloud at redshift 0.9: Ammonia in the gravitational lens PKS1830-211
• Submillimeter water and ammonia absorption by the peculiar z~0.89 interstellar medium in the gravitational lens of the PKS 1830-211 system
• The Photon Dominated Region in the IC 348 molecular cloud

Cited by in corpus (7)

• Molecules at z=0.89: A 4-mm-rest-frame absorption line survey toward PKS 1830-211
• An ALMA Early Science survey of molecular absorption lines toward PKS1830-211 -- Analysis of the absorption profiles
• Interstellar Silicate Dust in the z=0.89 Absorber Towards PKS 1830-211: Crystalline Silicates at High Redshift?
• ALMA Observations of Molecular Absorption in the Gravitational Lens PMN 0134-0931
• Discovery of CO absorption at z=0.05 in G0248+430
• A new constraint on the molecular oxygen abundance at $z\sim 0.886$
• New constraints on the values of the fundamental constants at a look-back time of 7.3 Gyr