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Lensed Quasars: Current Trends and Future Prospects

This conference in Santander, Spain in December 2004 focused on recent developments in lensed QSOs. Discussions included time delays for measuring H0, distribution of magnitude differences in various quasars, and challenges such as blending of images and low amplitude variations. The event highlighted methods for determining delays, errors, and lens modeling. Progress in lensed-quasar time-delays was emphasized, with various projects like VLA, Wise, NOT, and others contributing significantly. The discovery of SDSS 1004+4112, a large-separation cluster-lensed quasar, was a notable achievement discussed. The program also explored overcoming fundamental problems in the field and how statistics can aid in understanding large-scale structure formation history.

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Lensed Quasars: Current Trends and Future Prospects

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  1. 25 YEARS AFTER THE DISCOVERY: SOME CURRENT TOPICS ON LENSED QSOs Santander (Spain), 15th-17th December 2004 Wise Observatory Monitoring Projects: Introduction Dan Maoz, Tel-Aviv University

  2. large H0 Lensed quasar time delays for measuring H0 small H0

  3. Giveon et al. 1999: 7-year light curves for 42 PG QSOs

  4. Giveon et al. 1999: 7-year light curves for 42 PG QSOs

  5. Distribution of mag differences

  6. Q0957+561 Kundic et al. 1997

  7. 12. 0951+2635

  8. HE1104 - 1805

  9. HST/NICMOS F160W Kochanek et al., in prep.

  10. HE1104-1805 Time Delay History Wisotski et al. (1998) -270 days, but -100 possible Gil-Merino, Wisotski, & Wambsganss (2002)-310+/- 20days Pelt, Refsdal, & Stabell (2002) -255 to 330 days Schechter et al. (2003) no clear delay

  11. Ofek & Maoz (2003); long-term trend in A microlensing

  12. Ofek & Maoz (2003)

  13. Ofek & Maoz (2003)

  14. Delay = -160 +/- 7days Ofek & Maoz (2003)

  15. e.g., Kochanek 2002: Geometric delay gravitational (Shapiro) delay

  16. Delay = -160 +/- 7days H0=90? (Lehar et al. 2000) Ofek & Maoz (2003)

  17. Residuals in A – (delayed B): 1-month timescale, 0.07 mag amplitude Microlensing by Jupiters? (Wythe & Loeb 2002) Microlensing of relativistic motion in accretion disk? (Miralda-Escude & Gould 1997)

  18. Challenges and Problems: • Blending of images, lens galaxi(es) • Low amplitude variations • Sampling, gaps, intercalibration of diff. data sets • Uncorrelated variations due to • a. microlensing • b. others • 5. Method for determining delay, errors • 6. Lens modeling

  19. 12. 0951+2635

  20. PG 1115+080 Schechter et al. 1997

  21. SBS 1520+530 Burud et al. 2002

  22. B1600+434 Burud et al. 2002 (Also Koopmans et al. 2000)

  23. HE 2149-4735 Burud et al. 2000

  24. B1608+656 Fassnacht et al. 2002

  25. J0911.5+0551 Hjorth et al. 2002

  26. B0218+357 Biggs et al. 1999 (also Cohen et al. 2000)

  27. PKS1830-211 Lovell et al. 1998

  28. B1422+231 Patnaik & Narasimha 2001

  29. 0951+2635 Jakobsson et al. 2004

  30. Challenges and Problems: • Blending of images, lens galaxi(es) • Low amplitude variations • Sampling, gaps, intercalibration of diff. data sets • Uncorrelated variations due to • a. microlensing • b. others • 5. Method for determining delay, errors • 6. Lens modeling

  31. Lensed-quasar time-delays: Lots of progress in past few years; Massive Ongoing Programs: VLA, Wise, NOT, MDM, Maidanak, Calar Alto Increasing fraction of systems will have delay measurements. but How can some of the fundamental problems be overcome?

  32. Large-separation, cluster-lensed, quasars Statistics valuable for probing large-scale structure formation history

  33. Oguri et al. 2004 SDSS 1004+4112 the first (truly) large-separation lensed quasar

  34. SDSS 1004+4112 HST/ACS F814W Kochanek et al., in prep. D B A C

  35. Large-separation, cluster-lensed, quasars Statistics valuable for probing large-scale structure formation history but Also good for time delays/Ho: No microlensing No dust (flux ratios reliable) Multiple sources, lots of constraints

  36. A SDSS 1004+4112 Wise Obs. monitoring program Delay (A-B) > 2 weeks B

  37. Searching for more QSOs lensed by rich clusters

  38. Magellan, P. Schecter SDSS

  39. 25 YEARS AFTER THE DISCOVERY: SOME CURRENT TOPICS ON LENSED QSOs Santander (Spain), 15th-17th December 2004 • Two predictions/speculations • Measured time delays will become available for most systems, will play role in understanding galaxy structure and perhaps H0, after all. • Additional quasars lensed by clusters will be discovered / will have time delays, and may prove particularly useful.

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