С MB anisotropy induced by a moving straight cosmic string

1. СMB anisotropy induced by a moving straight cosmic string Sternberg State Astronomical Institute of Moscow State University Sazhina O.S. Sazhin M.V. Sementsov V.N. Capaccioli M. Longo G. Riccio G. 15th International Seminar on High Energy Physics QUARKS’2008 Sergiev Posad, Russia May 23-29, 2008

2. The main results • It was elaborated the method of searching for cosmic strings based on analysis of the CMB anisotropy; • Moving straight cosmic string was shown to generate distinctive structures of enhanced and reduced temperature fluctuations on the surface of last scattering; • It was analized the conditions under which a cosmic string could be detected by both CMB anisotropy and gravitational lensing.

3. Cosmic string in the Universe Euclidean Universe Сosmic strings have been introduced in theoretical cosmology by Kibble, 1976; Zeldovich, 1980; Vilenkin, 1981 B B A Conical Universe A

4. Cosmic string in the Universe

5. Cosmic string in the Universe

6. Cosmic string in the Universe The conical Universe is equivalent to euclidean Universe with cut Deficit angle

7. The cosmic string status in modern theoretical cosmology Among all possible types of topological defects, cosmic strings are particulary interesting and their existence finds support in superstring theories, both in compactification models and in theories with extended additional dimensions; From theoretical point of view for cosmic strings it is available the large mass range: from the GUT to electroweak energies.

8. ? fundamental strings of superstring theory cosmic strings

9. ? fundamental strings of superstring theory cosmic strings The energy scale for cosmic strings is the scale of GUT or less The energy scale for fundamental strings is Planck scale

10. ? fundamental strings of superstring theory cosmic strings Such heavy strings do not exist in our Universe today, and cannot have played any role in cosmological evolution except in the first few Planck times

11. fundamental strings of superstring theory cosmic strings Now we know models with large compact dimensions, in which the string scale may be much lower, down to the GUT scale or even less. cosmic strings branes Branes, which now play key role in superstring theory, can collide and generate cosmic strings.

12. The cosmic string status in modern observational cosmology The foreground-reduced internal linear combination map based on the 5 year WMAP data The current CMBR data exclude cosmic strings as source of primordial density perturbations. The data give the upper bound on the mass of cosmic strings but do not forbid their existence. The methods were oriented to search string networks only, not individual strings as we now proposed.

13. The temperature power spectrum based on the 5 year WMAP data

14. Optical surveys Looking for gravitational lensing events Radio surveys The investigations of the structure of CMB anisotropy Modern methods of cosmic string detection • Gravitational radiation from string loops • Interaction of string and black hole • Decay of heavy particles emitted by string • String + string interaction • ...

15. The investigations of the structure of CMB anisotropy looking for cosmic string footprints Looking for gravitational lensing events induced by cosmic string

16. The cosmological model in use

17. The simplу simulation of a straight cosmic string moving with constant velocity

18. CMB anisotropy induced by straight moving cosmic string

19. CMB anisotropy induced by straight moving cosmic string. Results of preliminary simulations. • R – distance from observer to string (in units of SLS); • v – string velocity (in units of c); • ψ– direction angle between line of sight and velocity of string. (R,v,ψ)

20. (R,v,ψ)=(0.9,0.9,90°)

21. (R,v,ψ)=(0.5,0.9,90°)

22. (R,v,ψ)=(0.1,0.9,90°)

23. Time retardation over the string extension (A.Vilenkin, 1986) • If an infinite straight string moves past the observer, he sees its distant parts with a retardation, so that the string appears to him to be curved string

24. R=0.15 v=0.1ψ=90° with retardation

25. R=0.15 v=0.4ψ=90° with retardation

26. R=0.15 v=0.7ψ=90° with retardation

27. (R,v,ψ)=(0.9,0.9,90°)

28. (R,v,ψ)=(0.9,0.5,90°)

29. (R,v,ψ)=(0.9,0.1,90°)

30. (R,v,ψ)=(0.9,0.9,45°)

31. (R,v,ψ)=(0.9,0.9,90°)

32. (R,v,ψ)=(0.9,0.9,120°)

33. The upper bound on string deficit angle. The induced anisotropy (amplitude of spot) is compared with anisotropy due adiabatic fluctuations and could be detected. The low observational limitduethe available resolution (Hubble Space Telescope) in optical searching of gravitational lensing events of galaxies by cosmic strings. “Superlight” strings could exist but can not be detected.

34. Why strings with deficit angle more than 10” does not exist? Because we do not observe such structures.

35. 200° 150° radio data (CMB) 100° optical data (lensing) 50° 0° z=2 z=4 z=6 z=8 z=0

36. Minimal string number N ~ 10 Maximal string number N ~ 1000

37. Main conclusions • We found the structure of the CMB anisotropy generated on a cosmic string for simple model of straight string moving with constant velocity; • The number of strings that could be detected by optical method is only 20%, therefore the gravitational lensing method has to be “completed” by CMB one; • For strings with deficit angle 1-2 arcsec the amplitude of generated anisotropy has to be 15-30 microK (the corresponding string linear density is and energy is GUT one, ); • To use both radio and optical methods the deficit angle has to be from 0.1 arcsec to 5-6 arcsec. • If cosmic string could be detected by optical method, the hight of corresponding brightness spot of anisotropy has to be no less than 100°.

38. Thank you for attention