1. Survey Science Group Workshop 2013-02-15 박명구, 한두환 ( 경북대 )

3. Quasar gravitational lens  Quasar lensing –quasars lensed by galaxies/clusters/dark objects –images: 2 to 4 –separation 0.34” ~ 15.9” 0.34” ~ 15.9” mostly in 0.5” ~ 4” mostly in 0.5” ~ 4”

4.  CASTLES –CfA-Arizona Space Telescope LEns Survey –lensed quasars (as of 2013/02) Class A: 82 cases (I’d bet my life.) Class A: 82 cases (I’d bet my life.) Class B: 10 cases(I’d bet your life.) Class B: 10 cases(I’d bet your life.) Class C:8 cases(I’d bet your life and you should worry.) Class C:8 cases(I’d bet your life and you should worry.)

6. Quasar Lensing & SDSS  Quasar lensing –multiple image quasars lensed by galaxy/cluster –SDSS quasar sample lensing probability: ~10 -3 lensing probability: ~10 -3 100 lens systems expected from spectroscopic sample of 10 5 SDSS quasars 100 lens systems expected from spectroscopic sample of 10 5 SDSS quasars 1000 lens systems plausible from 10 6 quasars expected in 10 4 deg 2 1000 lens systems plausible from 10 6 quasars expected in 10 4 deg 2 well-defined sample?? well-defined sample?? –Well-defined selection function needed for statistical analysis

7. Statistics of lensing  Tests –probability of lensing (number of lensed quasars) –configuration of lensing image number, separation, geometry image number, separation, geometry brightness ratio brightness ratio  Depends on –cosmology –lenses mass distribution mass distribution spatial distribution spatial distribution evolution in z evolution in z –sources evolution in z evolution in z

8. Probability Test

9.  Lee & Park (1994, 1998)  Im et al. (1997)  Chiba & Yoshii (1997, 1999)

10.  Chae et al. (2003) –radio selected sample

11.  Complications in lensing statistics –mass model of individual galaxy –sample construction –selection effects of surveys –magnification bias faint sources get brightened and detected faint sources get brightened and detected source distribution in luminosity and z needed source distribution in luminosity and z needed

12. Sloan digital sky survey Quasar Lens Search (SQLS)

13. –Follow-up confirmation spectroscopic observation spectroscopic observation photometric observation photometric observation

14. –SDSS image

15. –Follow-up imaging

17. –Spectroscopic confirmation

18. Constraints on Dark Energy and Evolution of Massive Galaxies

19.  Theoretical model –singular isothermal ellipsoid –velocity function –redshift evolution

20. –quasar luminosity function –lensing cross section over lensing area –lensing probability

21. –quasars should be brighter than lens –completeness function –probability distribution

22. –numbers of lensed quasars –likelihood

23.  image separation distribution

24.  flat universe

25.  without galaxy evolution

26.  with galaxy evolution

27.  redshift evolution of velocity function

28.  Worries –quasar luminosity function and its evolution –galaxy velocity function and its evolution –galaxy number evolution and its evolution

29. Image Separation Statistics  한두환  advantages & disadvantages –less sensitive to dark energy –magnitude bias not required –source information not needed

31.  JVAS vs SQLS

32. Curvature test –mean image separation –magnitude selection: lens should be bright enough

34. Image Separation Test  Theoretical model –singular isothermal sphere –velocity function –lensing probability

35. –differential probability

36. –expected vs observed concordance model

37.  Likelihood

38. z > 2.2 sample

39.  MC check –generate mock sample from theoretical probability distribution: 100, 1000 –apply the same test

40.  With galaxy evolution

41.  constraints on galaxy evolution

42. Summary  Lensing statistics –contains information on cosmology and galaxies –need to be careful –the more, the better: eBOSS, BigBOSS …