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Submillimeter Observations of NGC 4151: Evidence for Thermal Dust Emission

Published online by Cambridge University Press:  07 August 2017

M. A. Malkan ,
W. K. P. Gear ,
R. A. Edelson  and
E. I. Robson
M. A. Malkan
Affiliation:
Department of Astronomy, Math-Sciences Building, University of California, Los Angeles, CA 90024-1562, U. S. A.
W. K. P. Gear
Affiliation:
Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, Scotland, U. K.
R. A. Edelson
Affiliation:
Center for Astronomy and Space Astrophysics, University of Colorado, Boulder, CO 80309-0391, U. S. A.
E. I. Robson
Affiliation:
Department of Physics and Astronomy, Lancashire Polytechnic University, Preston PR1 2TQ, England, U. K.

Extract

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Observations of NGC 4151 were made with the JCMT on UT 20 April 1988. The detector was the UKT14 system, a dual-beam, 3He cooled, composite doped Germanium bolometer. A bandpass filter was used to define a central wavelength of 438 μm (685 GHz) with a bandwidth of 84 GHz. The beam was approximately Gaussian, with a FWHM of 11′, and the pointing was good to A very significant 5σ upper limit of 200 mJy was obtained. The Figure shows the continuum energy distribution for NGC 4151, made without correcting for beam size. When combined with the measured 155 μm flux density of 4.8 Jy, a lower limit on the spectral index of α155–438μm ≥ +3.06 is derived. Since the steepest cut off allowed by synchrotron self-absorption is α = +2.5, these observations can place an upper limit on the flux at 155 μm arising from a synchrotron self-absorbed source, with the rest arising from a thermal dust source.

Type
Part 7: Dust, Molecules, Infrared and MM Radiation
Information
Symposium - International Astronomical Union , Volume 134: Active Galactic Nuclei , 1989 , pp. 398 - 399
Copyright
Copyright © Kluwer 1989 

References

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