elt@astrovax.UUCP (Ed Turner) (12/01/83)
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After a hiatus of nearly two years since the discovery of 2345+007, two
(count them two, not one) new gravitational lenses have been discovered.
Ironicly, both were confirmed by optical spectroscopy on the night of 8 Oct
83 UT by independent groups working in ignorance of one another's programs.
One (2016+112ABC) was confirmed with the 200-inch at Palomar by C. Lawrence
(MIT+CIT), D. Schneider and M. Schmidt (CIT), B. Burke C. Bennett and J.
Hewitt (MIT), and E. Turner and J. Gunn (Princeton). The other (1635+267AB)
was confirmed with the KPNO 4-m by S. Djorgovski and H. Spinrad (Berkeley).
Preprints describing both objects have appeared, and the paper announcing
the discovery of 2016+112 has been scheduled for the 30 Dec issue of
SCIENCE.
The vital statistics of each system are given in the table below.
Additional interesting points include: 1) 2016 exhibits unprecedentedly
narrow lines for a quasar like objects. They are so far unresolved with
upper limits on the FWHM of order 1000 k/s. 2) 2016C appears to be a good
candidate for the lensing galaxy though no redshift is available.
Morphology and photometry are consistent with a brightest cluster galaxy
with z near 0.8. 3) A preliminary VLB experiment has detected fringes for
2016. 4) 1635 shows no sign of a lensing object or a third image even on
deep (but poor seeing) CCD images. 5) 1635A shows a single strong
absorption feature which Djorgovski and Spinrad tentatively identify as
MgII-2799 at z=1.118 and could be associated with the lensing object.
2016+112 1635+267
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RA (1950) 20 16 55.47 16 34 59.1
DEC (1950) +11 17 46.6 +26 42 06
optical images two stellar, one diffuse two stellar
radio images three unresolved at 0.1" radio quiet
stellar image separation 3.3" 3.8"
redshifts 3.273 1.961
redshift differences (A-B) <0.0005 <0.0008
apparent mag. (red) A=B=22.5 C>=23 A=19.2 B=20.8
radio fluxes A=22mJ B=23mJ C=68mJ (6cm) <7mJ (13cm)
sample VLA survey grism survey
identified lines Ly-a,N-V,SiO-IV,C-IV,He-II C-IV,C-II
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Ed Turner
astrovax!elt