1. C&A 17April06 1 Point Source Detection and Localization using DC2 pulsars Toby Burnett University of Washington

2. C&A 17April06 2 How good is the UW localization? I showed this last time: Do I believe the localization error? (Projected sigma) Many of the DC2 catalog sources are 3-4  away. Seth raised this question with me, and suggested a method to check: the pulsar positions were generated according to the ephemeris catalog positions: so I know the truth for all 100! Algorithm: Newton’s method, add gradient and curvature for all levels, iterate until small change. Determine error circle radius from curvature. –Note that a simple “weighted sum” is not a good estimator, in fact disastrous if  ≤2. Note differs by (0.018, -0.035) from catalog position, 4 sigma away. How about a strong source? Vela localization is 0.003 deg. Example: MRF320

3. C&A 17April06 3 Fitting the pulsar ephemeris sources Table has 100 entries, one duplicate position –62 detected, good fit. Resolutions from 0.001 to 0.15 degrees –20 apparently detected, but not localized (too weak, confusing background?) –17 not detected

4. C&A 17April06 4 The brightest sources Two sources are much more significant for localization (since very hard) than Vela (PSR_B0833m45) Geminga (PSR_J0633p1746) almost as good as Vela, Crab (PSR_B0531p21) factor of 2 worse. Fit converged for PSR_B1706m44, but apparent confusion

5. C&A 17April06 5 Status Error looks OK, validating likelihood analysis. Some anomalies, (more for less significant sources), will wait for the new runs to study