1 / 17

(More) Cosmological Tests from COSMOS Lensing

(More) Cosmological Tests from COSMOS Lensing. in 2009-2010: - photo-zs have improved dramatically - images/psf now corrected for CTE - new shear calibration underway + updated group catalog(s)

basil-brennan
Download Presentation

(More) Cosmological Tests from COSMOS Lensing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. (More) Cosmological Tests from COSMOS Lensing in 2009-2010: - photo-zs have improved dramatically - images/psf now corrected for CTE - new shear calibration underway + updated group catalog(s) so expect stronger signal around peaks in lensing map, and cleaner dependence on source and lens redshift  time for some 2nd generation tests of the lensing signal

  2. Measuring Geometry: Shear Ratio Test (Jain & Taylor 2003, Bernstein & Jain 2004, Taylor et al. 2007) Take ratio of shear of objects behind a particular cluster, as a function of redshift Details of mass distribution & overall calibration cancel  clean geometric test Can extend this to continuous result by fitting to all redshifts Z(z)  DLS/DS Relative Lensing Strength Z(z) Your cluster goes here Bartelmann & Schneider 1999

  3. To get a well-defined lens redshift, try looking behind clusters Base: h = 0.73, m = 0.27 ( or X = 1 - m) Variants (different curves): m = 0.25,0.30,0.32 w0 = -1,-0.95,-0.9,-0.85,-0.8 w(z) = w0 + wa(1-a) with w0 = -1, wa = 0.05, 0.1 h = 0.7, 0.75 Lens at z = 0.2 Use strength of signal behind cluster as a function of redshift to measure DA(z): weak but distinctive signal; relativechange (change in distance ratio)is only 0.5% 0.5% relative change

  4. To get a well-defined lens redshift, try looking behind clusters Base: h = 0.73, m = 0.27 ( or X = 1 - m) Variants (different curves): m = 0.25,0.30,0.32 w0 = -1,-0.95,-0.9,-0.85,-0.8 w(z) = w0 + wa(1-a) with w0 = -1, wa = 0.05, 0.1 h = 0.7, 0.75 Lens at z = 0.5 Use strength of signal behind cluster as a function of redshift to measure DA(z): weak but distinctive signal; relativechange (change in distance ratio)is only 0.5% 0.5% relative change

  5. How to stack clusters? Tangential shear goes as: so redshift dependence enters via critical surface density: Thus if we define (assumes flat models) and then independent of cosmology

  6. Try this behind COSMOS Groups and Clusters (X-ray derived Mass) Log(volume) (plot from Leauthaud et al. 2009)

  7. ~67  in top 14 objects? Try this behind COSMOS Groups and Clusters (X-ray derived Mass) Log(volume) (plot from Leauthaud et al. 2009)

  8. could get another ~60  from less massive groups? Try this behind COSMOS Groups and Clusters (X-ray derived Mass) Log(volume) (plot from Leauthaud et al. 2009)

  9. We see the signal! Stack of regions within 6’ of ~200+ x-ray groups good fit in front of/behind cluster significance still unclear; seems less than expected effect of other structures along the line of sight decreases chi2, but hard to quantify

  10. Local Dwarfs in Cosmos A surprising number of nearby galaxies show up in the COSMOS field

  11. Local Dwarfs in Cosmos A surprising number of nearby galaxies show up in the COSMOS field

  12. Local Dwarfs in Cosmos A surprising number of nearby galaxies show up in the COSMOS field

  13. Local Dwarfs in Cosmos plus lots of other weird LSB stuff…

  14. Local Dwarfs in Cosmos All booming away in the FUV, NUV…

  15. Local Dwarfs in Cosmos Where could these be?

  16. Local Dwarfs in Cosmos Where could these be?

  17. Local Dwarfs in Cosmos Leo I: 10 Mpc dist., mu ~25 3.3 Mpc away in projection Leo II: 20 Mpc dist., mu =30.5 1.74 Mpc away in projection Where could these be? NB: if in LEO II, Implies ~120 galaxies in group

More Related