NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-07-18 T09:05:25 PDT
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For refcode 1989AJ.....97..777E:
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1989AJ.....97..777E ACCURATE GALACTIC N_H_ VALUES TOWARDS QUASARS AND AGN MARTIN ELVIS Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 FELIX J. LOCKMAN National Radio Astronomy Observatory, Edgemont Road, Charlottesville, Virginia 22903 BELINDA J. WILKES Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 Received 18 October 1988 ABSTRACT We have measured integrated Galactic 21 cm column densities toward ~174 quasars and active galactic nuclei using the NRAO 140 ft telescope at Green Bank. These data have been corrected for stray radiation with the technique of Lockman et al. (1986). The 21 arcmin beam size of the 140 ft is small enough to minimize the uncertainty in N_H_ due to angular variations in the H I of the Galaxy at high latitudes. The resulting column densities are accurate to ~1 X 10^19^ atoms cm^-2^ or ~5%, whichever error is larger. Opacity uncertainties dominate the errors above N_H_ ~4 X 10^20^ atoms cm^-2^.
Retrieve 174 NED objects in this reference.
Please click here for ADS abstract

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