🚀 go-pugleaf

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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