NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
interstellar cyanogen and the temperature of the cosmic microwave background radiationWe present the results of a recently completed effort to determine the amount of CN rotational excitation in five diffuse interstellar clouds for the purpose of accurately measuring the temperature of the cosmic microwave background radiation (CMBR). In addition, we report a new detection of emission from the strongest hyperfine component of the 2.64 mm CN rotational transition (N = 1-0) in the direction toward HD 21483. We have used this result in combination with existing emission measurements toward our other stars to correct for local excitation effects within diffuse clouds which raise the measured CN rotational temperature above that of the CMBR. After making this correction, we find a weighted mean value of T(CMBR) = 2.729 (+0.023, -0.031) K. This temperature is in excellent agreement with the new COBE measurement of 2.726 +/- 0.010 K (Mather et al., 1993). Our result, which samples the CMBR far from the near-Earth environment, attests to the accuracy of the COBE measurement and reaffirms the cosmic nature of this background radiation. From the observed agreement between our CMBR temperature and the COBE result, we conclude that corrections for local CN excitation based on millimeter emission measurements provide an accurate adjustment to the measured rotational excitation.
Document ID
19930071093
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Roth, Katherine C.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Meyer, David M.
(Northwestern Univ. Evanston, IL, United States)
Hawkins, Isabel
(California Univ. Berkeley, United States)
Date Acquired
August 16, 2013
Publication Date
August 20, 1993
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters
Volume: 413
Issue: 2
ISSN: 0004-637X
Subject Category
ASTROPHYSICS
Funding Number(s)
CONTRACT_GRANT: NAS5-30180
CONTRACT_GRANT: NSF AST-90-21641
CONTRACT_GRANT: NSF AST-90-23372
Distribution Limits
Public
Copyright
Other