The Morphological Selection Criterion of the US Survey.
Session 24 -- AGNs/QSOs - High Luminosity
Display presentation, Tuesday, June 13, 1995, 9:20am - 6:30pm

## [24.07] The Morphological Selection Criterion of the US Survey.

P.D.Usher (Penn State), K.J. Mitchell (GSC), K-L.Huang (Nanjing)

The US survey selects objects from original plates of the Palomar 1.2m Schmidt camera. These objects have: (1) Ultraviolet color excess, and (2) Starlike morphology. Criterion (1) has been basic to color-selected quasar samples from the beginning, but little effort has been made to quantify criterion (2). The US survey intentionally included some resolved objects for that purpose. Spectroscopic identifications of US objects are now sufficiently numerous that the interface between unresolved QSOs and resolved galaxies has become clearer. The US survey is found to contain some resolved or possibly resolved objects with absolute magnitudes $M_{B} < -23.0$. Objects of the US survey satisfying the Veron criterion $M_{B} \leq -24.0$ are sufficiently luminous to be unresolved by the Palomar 1.2m Schmidt camera.