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Title: DETECTION OF OH{sup +} IN TRANSLUCENT INTERSTELLAR CLOUDS: NEW ELECTRONIC TRANSITIONS AND PROBING THE PRIMARY COSMIC RAY IONIZATION RATE

We present the detection of rotationally resolved electronic transitions in the OH{sup +} A{sup 3}Π–X{sup 3}Σ{sup −} (0, 0) and (1, 0) bands toward CD-32 4348, HD 63804, HD 78344, and HD 80077. These four translucent clouds have been studied in a recent Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph observational run. In total, seven absorption features of OH{sup +} are detected, and six of them are identified here for the first time, providing a precise tool to trace OH{sup +} in translucent interstellar clouds. An improved set of line positions and oscillator strengths is compiled to support our data interpretation. A dedicated analysis of the observed features in individual targets yields an accurate determination of OH{sup +} column densities. The results are applied to estimate the primary cosmic ray ionization rate in the investigated translucent clouds, which yields a typical value of ∼1.0 × 10{sup −16} s{sup −1}. In addition, following this work, two of the new interstellar features recently reported by Bhatt and Cami, at ∼3572.65 and 3346.96 Å, can be identified as OH{sup +} absorption lines now.
Authors:
;  [1] ;  [2] ;  [3]
  1. Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden (Netherlands)
  2. Instituto de Astronomia, Universidad Catolica del Norte, Av. Angamos 0610, Antofagasta (Chile)
  3. Center for Astronomy, Nicholas Copernicus University, Gagarina 11, Pl-87-100 Toruń (Poland)
Publication Date:
OSTI Identifier:
22518970
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 805; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ABSORPTION SPECTROSCOPY; CLOUDS; DENSITY; HYDROXY COMPOUNDS; INTERSTELLAR SPACE; IONIZATION; MOLECULAR IONS; MOLECULES; OSCILLATOR STRENGTHS; PRIMARY COSMIC RADIATION; PROBES; TELESCOPES; ULTRAVIOLET RADIATION