1. Prospects for observing quasar jets with the Space Interferometry Mission Ann E. Wehrle Space Science Institute, La Canada Flintridge, CA, and Boulder, CO Introduction The Space Interferometry Mission- Planetquest (SIM) will be an optical spaceborne Michelson interferometer with a 9- meter science baseline. The fringe spacing will be approximately 10 milliarcseconds, yielding resolution a factor of 10 better than that of the Hubble Space Telescope. SIM will have differential astrometric accuracy in a single visit of about 1 microarcsecond for bright targets (V<~12), relative to a grid of foreground stars. SIM achieves this unprecedented accuracy by chopping between the target and one or more reference stars (red giant stars at distances of 1- 2 kpc) less than a degree away. We will be able to measure internal motions of parsec-scale radio jets at the microarcsecond level (a fast VLBI blob moving at 1 milliarcsecond per year corresponds to motion of ~ 0.1 microarcsecond per hour). We will also be able to search for binary black holes, such as are suspected in OJ287, by measuring shifts in the photocenter, caused by gravitational reflex motion, as the black holes orbit the center of mass. Conclusion and Prospects SIM can measure internal motions in hundreds of bright quasars found in recent surveys. Two quasar Key Projects have been chosen, however, each contain only a small fraction of the nearby quasars that SIM could observe. SIM Planetquest will be reviewed in the next Decadal Survey, having already been recommended by the 1990 and 2000 surveys. A new call for observing time will be issued after a new launch date is set by NASA. Method Much work has been done recently on faint quasar surveys such as the Sloan Digital Sky Survey, which intentionally excluded quasars brighter than 16th magnitude. The Veron Cetty-Veron catalogs have many bright quasars accessible to SIM, but we were interested in finding out if there are additional bright quasars discovered in new surveys. We selected and examined the recent Asiago-ESO/ROSAT All Sky Survey (northern sample) (Grazian et al. 2002 AJ 124, 2955), in which 22 new spectroscopic identifications were made. The northern and southern samples yield a statistically complete sample of 340 AGN with redshifts less than or equal to 0.3. The redshifts and optical magnitudes of AGN in the survey are plotted below. We used the SIM Time and Performance Estimator to calculate the expected differential position measurement accuracy for a single visit, chopping between the target and with 5 reference stars, for targets between 13th and 17th magnitude in V band. Compare to the scale of “typical” superluminal motion: a VLBI blob moving at 1 milliarcsecond per year moves about 1 microarcsecond in 10 hours. For more information See the SIM Planetquest website at http://planetquest.jpl.nasa.gov Aim Our goal is to understand the big picture but we need to pick bright targets: ● Accretion onto massive black holes fuels the energetic AGN phenomena – but how does it work? ● How are galaxy mergers related to the AGN phenomenon - do binary black holes result from mergers and how common are they? ● What are the sizes and geometric relations between the components of the core region (jets, accretion disk, hot corona) ? ● How much do viewing direction and observational selections affect the picture? Specifically, ● Does the most compact non-thermal optical emission from an AGN come from an accretion disk or from a relativistic jet? ● Does the separation of the radio core and optical photocenter of the quasars used for the reference frame tie change on the timescales of their photometric variability, or is the separation stable? The magnitude distribution of AGN in Asiago-ESO/RASS northern survey shows that there are many bright targets accessible to SIM Planetquest, at a wide range of redshifts. Three more distant quasars are not shown. The single-visit differential SIM position accuracy in a single dimension is a strong function of the target brightness. Targets as faint as 17th magnitude are easily accessible to SIM.