SBS 0909+532: A New Double Gravitational Lens or Binary Quasar?

The z=1.377, B=17.0 mag quasar SBS 0909+532 A, B is a double with two images separated by 1.107 +/- 0.006 arcsec. Because the faint image has an emission line at the same wavelength as the MgII 2798 A emission line of the quasar, and lacks the broad MgIb absoption feature expected for a star with the same colors (a K star), we conclude that image B is a quasar with similar redshift to image A. The relative probabilities that the double is the smallest separation (4.8/h kpc for \Omega_0=1) correlated quasar pair or a gravitational lens are \sim 1:10^6. If the object is a lens, the mean lens redshift is $=0.5$ with 90% confidence bounds of 0.18 < z_l < 0.83 for \Omega_0=1. If the lens is an elliptical galaxy, we expect it to be brighter than I < 19.5 mag. The broad band flux ratio varies with wavelength, with \Delta I=0.31, \Delta R=0.58, and \Delta B=1.29 magnitudes, which is difficult to reconcile with the lensing hypothesis.Comment: 19 pages, 6 figures, ApJ in pres

The Digitized First Byurakan Survey

In the framework of a collaboration between the members of the group of High Energy Cosmic Sources (SCAE) within the Department of Physics at the University La Sapienza, Rome, and scientists of the Byurakan Astrophysical Observatory, we decided to preserve the large collection of spectral astronomical plates known as the First Byurakan Survey (FBS) by transforming it into an electronic archive, accessible by computers through the World Wide Web. This collection was obtained by Benjamin E. Markarian and collaborators in the years 1965-80 and covers a large part of the sky observable at our latitudes. The Infrared Projects Group within the Department of Astronomy at Cornell University (USA) joined this project. The project has been carried on during several years and required a substantial e ort, largely sustained by funding from the Sapienza University and the Italian Ministry of Research (MIUR), with additional support from the US Civilian and Research Development Foundation. Today the results are freely accessible to the world astronomical community through a dedicated web interface and include digitization of 90% of the FBS. This book describes the history of the FBS, the most important results obtained with it, and presents the electronic version (Digitized First Byurakan Survey, DFBS)