1. C M B S e c o n d a r y A n i s o t r o p i e s a t
R e i o n i z a t i o n
Detecting distant clusters with lensing of the OV Effect
Jose M. Diego & D. Herranz, 2008
(IFCA, Santander, Spain)

2. Ionized cloud CMB SZt (nT) SZk, OV (nV) Bremstrahlung or FF and
Relativistic electrons (n2T-0.5)
Thomson scattering of CMB photons also produce polarization

3. Polarization Double scattering CMB quadrupole Kinetic polarization
Kamionkowski & Loeb 1997
Lavaux, Diego, Mathis & Silk 2004

4. N = No(1+z)3

5. Z = 14

6. Z = 7.5

7. Z = 3.9

8. Z = 2.5

9. Z = 1

10. Z = 0.15

11. Z = 0

12. Z OV Z SZ

13. CMB and the
OV effect V
z ~ 10
Observer
Dark Ages
CMB at z=1100

14. Science with the OV effect
Probes re-ionization history.
Anticorrelates with 21-cm line (SKA, LOFAR)
Can be used as a background for lensing studies.
Detection of high-redshitf clusters or proto-clusters
Estimation of masses of clusters. Crucial for cosmology studies
A new window to study the end of the “Dark Ages”.

15. Small scale anisotropies due to the OV effect
Similar to Kinetic SZ but due
to reionization.
Strength of signal depends on
reionization history.
Few microK on scales of
10-30 arcsec.
Posible detection with next
generation experiments.
6 arcmin

16. Lensing by a galaxy cluster

17. Lensing by galaxy clusters
Direct way to measure
total mass (baryonic and
non-baryonic).
Masses necesary for
cosmological studies.
Needs high resolutions
Lensing studies have been
dominated by optical data.
Are observations of lensing of CMB anisotropies realistic ?

18. Ostriker Vishniac effect
6 arcmin

19. Ostriker Vishniac effect
6 arcmin

20. Ostriker Vishniac effect
6 arcmin

21. Optimal Filters (Stokes Parameters)Q U

22. Optimal Filters (2D maps)Q U

23. Example of optimally filtered data
(noise+beam)
OF data
OV effect

24. RESULTS
Signal-to-noise depends on cluster masses and instrumental noise.
Massive distant clusters should be seen by experiments with 0.3 microK per arcmin.

25. RESULTS Signal-to-noise depends also on the angular
resolution of the experiment. Resolutions of 10 arcsec or less are necessary to observe the effect.

26. But, point sources will be the main limiting factor.
RESULTS
But, point sources will be the main limiting factor.
Sources need to be removed down to the microJy level.

27. But can we see this at all ?
Not yet but soon. One needs:
High resolution. 50 meter or larger antena
Or interferometers. Today’s standard.
High sensitivity. 0.2 microK per arcmin or better. Improve one order of magnitude.
Point source substraction. About a hundred point sources need to be removed or accounted for per arcminute. Biggest challenge but possible with interferometric techniques.
ALMA ?

28. Conclusions
OV effect can be used as a background source for lensing studies of galaxy clusters.
Optimal filters can be designed to improve the detection rate of lensing signals.
This signal could be detected with ALMA ?
Same technique can be applied to 21-cm line background.
V E R Y E X C I T I N G Y E A R S A H E A D !

30. Science Fiction Science is Here
Let’s destroy the
entire Universe !
What should we do
with all this new
technology Spock ?
We are out of
photonic torpedos !