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A parseltongue pipeline for VLA analysis of B1600+434

A parseltongue pipeline for VLA analysis of B1600+434. Alicia Berciano Alba (JIVE/Kapteyn Institute) Leon Koopmans (Kapteyn Institute) Mike Garrett (JIVE) Olaf Wucknitz (JIVE). Copenhagen, Nov 2006. Once upon a time… Strong Lensing. Effects related with anomalies in lens images.

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A parseltongue pipeline for VLA analysis of B1600+434

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  1. A parseltongue pipeline for VLA analysis of B1600+434 Alicia Berciano Alba (JIVE/Kapteyn Institute) Leon Koopmans (Kapteyn Institute) Mike Garrett (JIVE) Olaf Wucknitz (JIVE) Copenhagen, Nov 2006

  2. Once upon a time… Strong Lensing

  3. Effects related with anomalies in lens images CDM Substructure Dwarf satellites Small disks (Möller et al. 2003) Clusters in the los (Fassnach) • Wrong mass model • Absorption by dust • Free-free absorption in the lens galaxy (e.g. B0218+357, Mittal thesis 2006) • Differential Scattering in the lens galaxy (e.g. 0128+437, Biggs et al. 2004) • Scintillation in our own galaxy • Microlensing by stars

  4. A B CLASS B1600+434 • Lens: edge-on spiral galaxy at z = 0.41 • Background source: QSO at z = 1.59 (Fassnacht & Cohen 1998) • 2 images (flat spectrum radio sources) • A passes through the DM halo • B passes through the disk and bulge (Koopmans et al 1998)

  5. Why is B1600+434 interesting ? The light curve of image A shows stronger variability than image B Short-term variability in the difference lightcurve is bigger than the one expected from measurement errors  First unambiguous case of external variability in a radio lens!!

  6. Current explanation “Flat spectrum radio sources not affected by microlensing” Neal Jackson, beginning of this session Counterpart example: static core + superluminal jet doopler boosting smaller angular sizes Source =

  7. Why does image B not show microlensing? A Scatter-broadening in disk? (Koopmans & de Bruyn 2000) B (Patnaik & Kemball 2001) INDEED!

  8. But Microlensing or Scintillation? (Koopmans & de Bruyn 2000) The way to quantitatively distinguish between microlensing and scintillation is their opposite behaviour with frequency WE NEED MULTI-FREQUENCY OBSERVATIONS!!

  9. The Data • VLA radio continuum • 361 epochs • 1 lens system + 4-5 flux calibrators • 13 Feb 1998 – 5 Jan 2003 • Observed Bands: L, C, X, P, U, K • VLA array config: A, B, AD, AB, BC, C, CD

  10. Automated data reduction • Run Files = classic AIPS scripting tool • ParselTongue = Python interface to classic AIPS And I have the experts at JIVE!!! • Mark Kettenis • Cormac Reinolds • James M. Anderson

  11. Block Diagram of the pipeline Flag phase calibrator Self calibration phase calibrator Phase self calibration sources Source model fitting Apply calibration to Sources Source Model Flag sources (lens + flux calibrators) calibrate sources Source Flux Source Maps

  12. First Test Results

  13. L-BAND Flagging Before Flagging After Flagging

  14. L-BAND Preliminary Maps

  15. C-BAND Flagging Before Flagging After Flagging

  16. C-BAND Preliminary Maps

  17. X-BAND Preliminary Maps Before Flagging After Flagging

  18. X-BAND Preliminary Maps

  19. Future Work on the pipeline • Implement the phase selfcal + model fitting in AIPS • Improve the Flagging (understand FLAGR) • Adapt the script to produce very good models of the flux calibrators and the source • Perform tests in each band and array configuration

  20. Future work on B1600+434 • Prepare the lightcurves from the data • Determine and improve the time delay • Test the different scenarios using the multifrequency lightcurves

  21. To stimulate your appetite…

  22. Scintillation / Microlensing

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