Cyanogen excitation in diffuse interstellar clouds

Abstract

view Abstract Citations (33) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Cyanogen Excitation in Diffuse Interstellar Clouds Roth, Katherine C. ; Meyer, David M. Abstract We present high signal-to-noise ratio observations of optical CN absorption from the B (2)sigma(+) -X (2)sigma(+) (0, 0) and (1, 0) vibrational bands in the five diffuse lines of sight toward zeta Ophiuchi, zeta Persei, HD 27778, HD 21483, and HD 154368. The observed level of CN excitation is consistent with direct satellite and rocket measurements of the cosmic microwave background radiation (CMBR), implying that local collision effects are small. The weak 2.64 mm CN line emission observed toward HD 21483 and HD 154368 is used to correct the observed CN excitation temperatures and derive a weighted mean CMBR temperature at 2.64 mm of 2.729(+0.023, -0.031) K which agrees remarkably well with the Cosmic Background Explorer Satellite (COBE) measurement obtained with the Far Infrared Absolute Spectrometer (FIRAS) instrument of 2.726 +/- 0.010 K. These absorption data were obtained during 10 separate observing runs, and we find excellent agreement between independent equivalent width measurements resulting from widely varying instrument combinations. Finally we discuss the limitations and future applications of CN excitation absorption-line measurements. Publication: The Astrophysical Journal Pub Date: March 1995 DOI: 10.1086/175343 Bibcode: 1995ApJ...441..129R Keywords: Background Radiation; Cyanogen; Excitation; Gas Temperature; Interstellar Matter; Line Spectra; Vibrational Spectra; Absorption Spectroscopy; Cosmic Background Explorer Satellite; Optical Measuring Instruments; Signal To Noise Ratios; Astronomy; COSMOLOGY: COSMIC MICROWAVE BACKGROUND; ISM: CLOUDS; ISM: MOLECULES full text sources ADS | data products SIMBAD (5)