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Lensing can create multiple images

The closer the light beam passes to the deflector, the greater is the deflection; for large impact parameters the image location IS the source location. In general, the source location is not observable. Lensing can create multiple images. “ SOURCE ”. Fritz Zwicky & Coma.

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Lensing can create multiple images

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  1. The closer the light beam passes to the deflector, the greater is the deflection; for large impact parameters the image location IS the source location. In general, the source location is not observable.

  2. Lensing can create multiple images “SOURCE”

  3. Fritz Zwicky & Coma

  4. QSO 0957+561lens z = 0.36, source z = 1.41, separation = 6.1’’ (huge!!)The very first known lens (Walsh, Weyman & Carswell 1979)

  5. Einstein Cross/Huchra’s Lens

  6. MACHO-96-BLG5 (candidate microlensing event in the bulge) Can’t resolve the two stellar images but can measure the increase in brightness accurately using differential photometry Genuine lensing events should follow the predicted amplification curve, never repeat, and be achromatic (except for limb darkening effects)

  7. Sample MACHO light curves Complications with interpretations: don’t know the distance to the dark object, so don’t know its tangential velocity, so don’t know the mass accurately. Most “MACHOs” were seen towards the bulge and most were consistent with star-star lensing.

  8. Giant Arc in Abell 370cluster z = 0.374, arc z = 0.725One of the first giant arcs to be discovered (Lynds & Petrosian 1986)arc length = 21”, mean thickness = 2”, radius of curvature = 15”

  9. Giant arc in cluster Cl2244-02One of the first arcs to be discovered (Lynds & Petrosian 1986) Existence of SINGLE giant arcs proves the cluster mass distribution cannot be spherical Note: HST FWPC2 FOV=3sq. arcmin. (= most cluster images prior to ACS are single pointings = only the central regions of most clusters)

  10. Galaxy clusters make great lenses (massive & centrally-condensed) Cl0024+16, with multiple images of the same galaxy

  11. Abell 2218 - the “Poster Child” of cluster lenses

  12. Cluster lens discovered in the SDSS Note: ACS FOV = 2x WFPC2

  13. First known 5-image QSO

  14. Galaxy Lens Candidates (HST Medium Deep Survey; Griffths, Ratnatunga et al.)

  15. Galaxy Lenses (most are ellipticals!)

  16. PG115+080one of the first “Einstein rings” to be discoveredring is lensed image of the QSO host galaxy

  17. “Einstein rings” made by galaxy lenses (SLACS Team; SDSS galaxies)

  18. “Double” Einstein Ring (galaxy lens)

  19. Cluster lenses magnify very distant galaxies! (Zwicky was right.) The record-holder in 1997 Lens is Cl1358+62 (z=0.33) Source is galaxy at z=4.92 (and the arc is not the only image of it!) XXX

  20. “SCUBA” sources first discovered via cluster lensing using JCMT (Blain et al. 1997) Top: 850 micron maps Bottom: 450 micron maps Left: A370 Right: Cl2244 Sub-mm galaxies at z=2 to z=3 that are undergoing massive amounts of star formation and are highly dust enshrouded; redshifts mostly come from radio counterparts

  21. A z=10 galaxy lensed by A1853 (?); Pello et al. (2004)

  22. Pello et al. have a 4-5 sigma detection of a single line in the spectrum; if that line is Lyman alpha, then the galaxy is at z=10 Star formation rate is ~60 solar masses per year (uncorrected for lensing) Stellar mass is ~8x108 solar masses Luminosity is ~2x1010 solar luminosities Lensing magnification is ~25 to 100

  23. Graham et al. (2005) failed to detect the galaxy with long Keck integrations, Spitzer observations, and a re-reduction of Pello et al.’s original data (from VLT archive)

  24. Confirmed z=7 galaxy seen through A2218 (Kneib et al. 2006) In principle, high-z galaxies seen through lenses should form an unbiased sample (but they are rare to find)

  25. zL = 0.63 zS = 1.39 H0 = 69.7+4.9-5.0 km/s/Mpc w = -0.94+0.17-0.19 Sherry Suyu, Roger Blandford, et al. (2010)

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