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4U1722 + 11 - The discovery of an X-ray selected BL Lac objectThe Uhuru X-ray source 4U1722 + 11 was observed using the microchannel-plate detector (High Resolution Imager) on the Einstein Observatory, and its coordinates measured to a precision of about 5 arcsec. A 16th-magnitude stellar object within the error circle was observed spectroscopically at CTIO, and at the AAT, and found to have a featureless continuum. Subsequent radio observations at the VLA have established that the object is a radio source at the level of 60 mJy, and optical polarization measurements have determined that the source exhibits variable polarization at the level of 10 percent. On the basis of these observations, it is concluded that 4U1722 + 11 is a member of the class of objects known as X-ray selected blazars of BL Lac objects.
Document ID
19890066183
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Griffiths, R. E.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Wilson, A. S.
(Maryland, University College Park, United States)
Ward, M. J.
(Cambridge, University England; Washington, University, Seattle, United States)
Tapia, S.
(Steward Observatory Tucson, AZ, United States)
Ulvestad, J. S.
(California Institute of Technology, Jet Propulsion Laboratory, Pasadena; Maryland, University College Park, United States)
Date Acquired
August 14, 2013
Publication Date
September 1, 1989
Publication Information
Publication: Royal Astronomical Society, Monthly Notices
Volume: 240
ISSN: 0035-8711
Subject Category
Astrophysics
Accession Number
89A53554
Distribution Limits
Public
Copyright
Other

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