21 centimeter HI absorption at z = 0. 437 against the extended radio structure of 3c 196

Journal Article · Sat Jan 01 04:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160575· OSTI ID:6240177

Brown, R L; Mitchell, K J

We report the detection of an absorption line at 988.7. MHz toward the quasar 3C 196. We identify this line as the lambda21 cm line of neutral atomic hydrogen seen at a redshift of z/sub abs/ = 0.4366. No optical absorption lines have been noted in the z/sub em/ = 0.871 quasar 3C 196 heretofore. All the radio emission of 3C 196 is contained in two thetaroughly-equal3'' extended lobes symmetrically placed (position angle approx.26/sup 0/) about the optical object. The optical QSO itself is an extremely weak, <1 mJy, radio source. Thus to account for the approx.0.5 Jy seen in the absorption line we infer that the diameter of the absorbing region must be at least as large as 750 pc and perhaps as large as, or larger than, 30 kpc. We note further than an optical wisp is seen extending approx.3'' x 1'' from the QSO at position angle approx.120/sup 0/, that is in a direction perpendicular to the separation of the radio lobes. If this wisp is the disk of an intervening galaxy, then the H i absorption is direct evidence for absorption in a galactic halo. Puzzles abound; (1) If the optical wisp seen superposed on the QSO is an intervening galaxy then what aspects, if any, of the emission from 3C 196 are gravitational lens effects. (2) If the wisp is associated with the QSO, why is it radio quiet and why is it orthogonal to the extended radio structure of 3C 196. (3) Is it significant that z/sub abs/ is one-half z/sub em/ within the errors.

• Research Organization: National Radio Astronomy Observatory
• OSTI ID: 6240177
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 264:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics &amp; Cosmology-- Quasi-Stellar
Radio
&amp; X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
COSMIC RADIO SOURCES
H1 REGIONS
MORPHOLOGY
QUASARS
RED SHIFT
SPECTRA