In situ measurement of the cosmic microwave background temperature at a distance of 7.5 kiloparsecs

Abstract

view Abstract Citations (1) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS In Situ Measurement of the Cosmic Microwave Background Temperature at a Distance of 7.5 Kiloparsecs Kogut, A. ; Petuchowski, S. J. ; Bennett, C. L. ; Smoot, G. F. Abstract Absorption of orthoformaldehyde (H2CO) toward the giant H II region W51A (G49.5 - 0.4) has been used as a remote probe of the cosmic microwave background (CMB) at a distance of 7.5 kpc. VLA observations of the 6 cm and 2 cm wavelength transitions provided sufficient resolution and sensitivity to resolve condensations within the foregound clouds. Solutions to the equations of statistical equilibrium within each condensation in the context of a large velocity gradient model yielded an estimate for the CMB temperature at 2.1 mm wavelength of 3.2 + or - 0.9 K. The uncertainty is dominated by modeling of collisional pumping by neutral hydrogen molecules (H2). Publication: The Astrophysical Journal Pub Date: January 1990 DOI: 10.1086/185627 Bibcode: 1990ApJ...348L..45K Keywords: Formaldehyde; H Ii Regions; Interstellar Gas; Relic Radiation; Very Large Array (Vla); Hydrogen Clouds; Molecular Clouds; Red Shift; Astrophysics; COSMIC BACKGROUND RADIATION; INTERSTELLAR: MOLECULES; NEBULAE: INDIVIDUAL ALPHANUMERIC: W51 full text sources ADS | data products SIMBAD (2)