elt@astrovax.UUCP (Ed Turner) (12/01/83)
----------------------------------------------------------------------------- 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 ------------------------- ------------------- 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 --------------------------------------------------------------------------- Ed Turner astrovax!elt