ON MEASURING THE COSMIC MICROWAVE BACKGROUND TEMPERATURE AT REDSHIFT 0.89

Journal Article · Wed Feb 20 04:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/764/2/132· OSTI ID:22167744

Sato, M.; Menten, K. M. ^[1]; Reid, M. J. ^[2]; Carilli, C. L. ^[3]

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1. Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany)
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
3. National Radio Astronomy Observatory, Socorro, NM 87801 (United States)

We report on a measurement of the temperature of the cosmic microwave background radiation field, T {sub CMB}, at z = 0.88582 by imaging HC{sub 3}N(3 <- 2) and (5 <- 4) absorption in the foreground galaxy of the gravitationally lens magnified radio source PKS 1830-211 using the Very Long Baseline Array and the phased Very Large Array. Low-resolution imaging of the data yields a value of T {sub rot} = 5.6{sup +2.5} {sub -0.9} K for the rotational temperature, T {sub rot}, which is consistent with the temperature of the cosmic microwave background at the absorber's redshift of 2.73(1 + z) K. However, our high-resolution imaging reveals that the absorption peak position of the foreground gas is offset from the continuum peak position of the synchrotron radiation from PKS 1830-211SW, which indicates that the absorbing cloud is covering only part of the emission from PKS 1830-211, rather than the entire core-jet region. This changes the line-to-continuum ratios, and we find T {sub rot} between 1.1 and 2.5 K, which is lower than the expected value. This shows that previous T {sub rot} measurements could be biased due to unresolved structure.

• OSTI ID: 22167744
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 764; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION SPECTRA
ASTRONOMY
ASTROPHYSICS
COSMOLOGY
EMISSION SPECTRA
GALAXIES
GRAVITATIONAL LENSES
NITRILES
PHOTON EMISSION
QUASARS
RED SHIFT
RELICT RADIATION
RESOLUTION
SYNCHROTRON RADIATION