Searching for Cosmic Strings in New Observational Windows

Transcription

1 1 / 62 in Searching for s in New Observational Windows Robert Brandenberger McGill University, Montreal, Canada; and Institute for Theoretical Studies, ETH Zuerich, Switzerland KITPC, Sept

2 2 / 62 Outline in Signature of s in High z Large-Scale Structure Surveys 5 of in 6 of in Maps 7 Effects of 8

3 3 / 62 Plan in Signature of s in High z Large-Scale Structure Surveys 5 of in 6 of in Maps 7 Effects of 8

4 s T. Kibble, J. Phys. A 9, 1387 (1976); Y. B. Zeldovich, Mon. Not. Roy. Astron. Soc. 192, 663 (1980); A. Vilenkin, Phys. Rev. Lett. 46, 1169 (1981). 4 / 62 string = linear topological defect in a quantum field theory. 1st analog: line defect in a crystal 2nd analog: vortex line in superfluid or superconductor string = line of trapped energy density in a quantum field theory. Trapped energy density gravitational effects on space-time important in cosmology. in

5 s T. Kibble, J. Phys. A 9, 1387 (1976); Y. B. Zeldovich, Mon. Not. Roy. Astron. Soc. 192, 663 (1980); A. Vilenkin, Phys. Rev. Lett. 46, 1169 (1981). 4 / 62 string = linear topological defect in a quantum field theory. 1st analog: line defect in a crystal 2nd analog: vortex line in superfluid or superconductor string = line of trapped energy density in a quantum field theory. Trapped energy density gravitational effects on space-time important in cosmology. in

6 s T. Kibble, J. Phys. A 9, 1387 (1976); Y. B. Zeldovich, Mon. Not. Roy. Astron. Soc. 192, 663 (1980); A. Vilenkin, Phys. Rev. Lett. 46, 1169 (1981). 4 / 62 string = linear topological defect in a quantum field theory. 1st analog: line defect in a crystal 2nd analog: vortex line in superfluid or superconductor string = line of trapped energy density in a quantum field theory. Trapped energy density gravitational effects on space-time important in cosmology. in

7 5 / 62 Relevance to Particle Physics and Cosmology I in strings are predicted in many particle physics models beyond the Standard Model". strings are predicted to form at the end of inflation in many inflationary models. strings may survive as cosmic superstrings in alternatives to inflation such as string gas cosmology. In models which admit cosmic strings, cosmic strings inevitably form in the early universe and persist to the present time. It would be nice to see a cosmic string in the universe!

8 5 / 62 Relevance to Particle Physics and Cosmology I in strings are predicted in many particle physics models beyond the Standard Model". strings are predicted to form at the end of inflation in many inflationary models. strings may survive as cosmic superstrings in alternatives to inflation such as string gas cosmology. In models which admit cosmic strings, cosmic strings inevitably form in the early universe and persist to the present time. It would be nice to see a cosmic string in the universe!

9 5 / 62 Relevance to Particle Physics and Cosmology I in strings are predicted in many particle physics models beyond the Standard Model". strings are predicted to form at the end of inflation in many inflationary models. strings may survive as cosmic superstrings in alternatives to inflation such as string gas cosmology. In models which admit cosmic strings, cosmic strings inevitably form in the early universe and persist to the present time. It would be nice to see a cosmic string in the universe!

10 Relevance to Particle Physics and Cosmology II in strings are characterized by their tension µ which is associated with the energy scale η at which the strings form (µ η 2 ). Searching for the signatures of cosmic strings is a tool to probe physics beyond the Standard Model at energy ranges complementary to those probed by the LHC. strings are constrained from cosmology: strings with a tension which exceed the value Gµ are in conflict with the observed acoustic oscillations in the angular power spectrum (Dvorkin, Hu and Wyman, 2011, Planck collab. arxiv: ). Existing upper bound on the string tension rules out large classes of particle physics models. It is interesting to find ways to possibly lower the bounds on the string tension. 6 / 62

11 Relevance to Particle Physics and Cosmology II in strings are characterized by their tension µ which is associated with the energy scale η at which the strings form (µ η 2 ). Searching for the signatures of cosmic strings is a tool to probe physics beyond the Standard Model at energy ranges complementary to those probed by the LHC. strings are constrained from cosmology: strings with a tension which exceed the value Gµ are in conflict with the observed acoustic oscillations in the angular power spectrum (Dvorkin, Hu and Wyman, 2011, Planck collab. arxiv: ). Existing upper bound on the string tension rules out large classes of particle physics models. It is interesting to find ways to possibly lower the bounds on the string tension. 6 / 62

12 Relevance to Particle Physics and Cosmology II in strings are characterized by their tension µ which is associated with the energy scale η at which the strings form (µ η 2 ). Searching for the signatures of cosmic strings is a tool to probe physics beyond the Standard Model at energy ranges complementary to those probed by the LHC. strings are constrained from cosmology: strings with a tension which exceed the value Gµ are in conflict with the observed acoustic oscillations in the angular power spectrum (Dvorkin, Hu and Wyman, 2011, Planck collab. arxiv: ). Existing upper bound on the string tension rules out large classes of particle physics models. It is interesting to find ways to possibly lower the bounds on the string tension. 6 / 62

13 Relevance to Particle Physics and Cosmology II in strings are characterized by their tension µ which is associated with the energy scale η at which the strings form (µ η 2 ). Searching for the signatures of cosmic strings is a tool to probe physics beyond the Standard Model at energy ranges complementary to those probed by the LHC. strings are constrained from cosmology: strings with a tension which exceed the value Gµ are in conflict with the observed acoustic oscillations in the angular power spectrum (Dvorkin, Hu and Wyman, 2011, Planck collab. arxiv: ). Existing upper bound on the string tension rules out large classes of particle physics models. It is interesting to find ways to possibly lower the bounds on the string tension. 6 / 62

14 Relevance to Particle Physics and Cosmology II in strings are characterized by their tension µ which is associated with the energy scale η at which the strings form (µ η 2 ). Searching for the signatures of cosmic strings is a tool to probe physics beyond the Standard Model at energy ranges complementary to those probed by the LHC. strings are constrained from cosmology: strings with a tension which exceed the value Gµ are in conflict with the observed acoustic oscillations in the angular power spectrum (Dvorkin, Hu and Wyman, 2011, Planck collab. arxiv: ). Existing upper bound on the string tension rules out large classes of particle physics models. It is interesting to find ways to possibly lower the bounds on the string tension. 6 / 62

15 Relevance to Particle Physics and Cosmology III in strings can produce many good things for cosmology: Explanation for the origin of primordial magnetic fields which are coherent on galactic scales (X.Zhang and R.B. (1999)). Explanation for cosmic ray anomalies (R.B., Y. Cai, W. Xue and X. Zhang (2009)). Origin of supermassive black holes (S. Bramberger, R.B., P. Jreidini and J. Quintin, 2015). Origin of globular clusters (A. Barton, R.B. and L. Lin, 2015; R.B., L. Lin and S. Yamanouchi, 2015). It is interesting to find evidence for the possible existence of cosmic strings. 7 / 62

16 Relevance to Particle Physics and Cosmology III in strings can produce many good things for cosmology: Explanation for the origin of primordial magnetic fields which are coherent on galactic scales (X.Zhang and R.B. (1999)). Explanation for cosmic ray anomalies (R.B., Y. Cai, W. Xue and X. Zhang (2009)). Origin of supermassive black holes (S. Bramberger, R.B., P. Jreidini and J. Quintin, 2015). Origin of globular clusters (A. Barton, R.B. and L. Lin, 2015; R.B., L. Lin and S. Yamanouchi, 2015). It is interesting to find evidence for the possible existence of cosmic strings. 7 / 62

17 8 / 62 Preview in Important lessons from this talk: strings nonlinearities already at high redshifts. of cosmic strings more pronounced at high redshifts. string wakes lead to perturbations which are non-gaussian. string wakes predict specific geometrical patterns in position space. 21 cm surveys provide an ideal arena to look for cosmic strings (R.B., R. Danos, O. Hernandez and G. Holder, 2010).

18 9 / 62 Plan in Signature of s in High z Large-Scale Structure Surveys 5 of in 6 of in Maps 7 Effects of 8

19 I A. Vilenkin and E. Shellard, s and other Topological Defects (Cambridge Univ. Press, Cambridge, 1994). strings form after symmetry breaking phase transitions. Prototypical example: Complex scalar field φ with Mexican hat" potential: V (φ) = λ ( φ 2 η 2) 2 4 Vacuum manifold M: set up field values which minimize V. in 10 / 62

20 11 / 62 Scalar Field Potential in

21 I A. Vilenkin and E. Shellard, s and other Topological Defects (Cambridge Univ. Press, Cambridge, 1994). in strings form after symmetry breaking phase transitions. Prototypical example: Complex scalar field φ with Mexican hat" potential: V (φ) = λ ( φ 2 η 2) 2 4 Vacuum manifold M: set up field values which minimize V. At high temperature: φ = 0. At low temperature: φ = η - but phase uncorrelated on super-hubble scales. defect lines with φ = 0 left behind. 12 / 62

22 I A. Vilenkin and E. Shellard, s and other Topological Defects (Cambridge Univ. Press, Cambridge, 1994). in strings form after symmetry breaking phase transitions. Prototypical example: Complex scalar field φ with Mexican hat" potential: V (φ) = λ ( φ 2 η 2) 2 4 Vacuum manifold M: set up field values which minimize V. At high temperature: φ = 0. At low temperature: φ = η - but phase uncorrelated on super-hubble scales. defect lines with φ = 0 left behind. 12 / 62

23 13 / 62 string core: points with φ η. Existence of cosmic strings requires: Π 1 (M) 1. in

24 13 / 62 string core: points with φ η. Existence of cosmic strings requires: Π 1 (M) 1. in

25 14 / 62 Formation of T. Kibble, Phys. Rept. 67, 183 (1980). By causality, the values of φ in M cannot be correlated on scales larger than t. Hence, there is a probability O(1) that there is a string passing through a surface of side length t. Causality network of cosmic strings persists at all times. in

26 14 / 62 Formation of T. Kibble, Phys. Rept. 67, 183 (1980). By causality, the values of φ in M cannot be correlated on scales larger than t. Hence, there is a probability O(1) that there is a string passing through a surface of side length t. Causality network of cosmic strings persists at all times. in

27 15 / 62 Scaling Solution I Correlation length ξ(t) < t for all times t > t c. Dynamics of ξ(t) is governed by a Boltzmann equation which describes the transfer of energy from long strings to string loops in

28 Scaling Solution II R. H. Brandenberger, Int. J. Mod. Phys. A 9, 2117 (1994) [arxiv:astro-ph/ ]. Analysis of the Boltzmann equation shows that ξ(t) t for all t > t c : If ξ(t) << t then rapid loop production and ξ(t)/t increases. If ξ(t) >> t then no loop production and ξ(t)/t decreases. Sketch of the scaling solution: in 16 / 62

29 17 / 62 History I in strings were popular in the 1980 s as an alternative to inflation for producing a scale-invariant spectrum of cosmological perturbations. strings lead to incoherent and active fluctuations (rather than coherent and passive like in inflation). Reason: strings on super-hubble scales are entropy fluctuations which seed an adiabatic mode which is growing until Hubble radius crossing. Boomerang data (1999) on the acoustic oscillations in the angular power spectrum ruled out cosmic strings as the main source of fluctuations.. Interest in cosmic strings collapsed.

30 History II in Supergravity models of inflation typically yield cosmic strings after reheating (R. Jeannerot et al., 2003). Brane inflation models typically yield cosmic strings in the form of cosmic superstrings (Sarangi and Tye, 2002; Copeland, Myers and Polchinski, 2004). String Gas Cosmology may lead to a remnant scaling network of cosmic superstrings (R.B. and C. Vafa, 1989: A. Nayeri, R.B. and C. Vafa, 2006). renewed interest in cosmic strings as supplementary source of fluctuations. Best current limit from angular spectrum of anisotropies: 5% of the total power can come from strings (see e.g. Dvorkin, Hu and Wyman, 2011, Planck collab., 2013). Leads to limit Gµ < / 62

31 History II in Supergravity models of inflation typically yield cosmic strings after reheating (R. Jeannerot et al., 2003). Brane inflation models typically yield cosmic strings in the form of cosmic superstrings (Sarangi and Tye, 2002; Copeland, Myers and Polchinski, 2004). String Gas Cosmology may lead to a remnant scaling network of cosmic superstrings (R.B. and C. Vafa, 1989: A. Nayeri, R.B. and C. Vafa, 2006). renewed interest in cosmic strings as supplementary source of fluctuations. Best current limit from angular spectrum of anisotropies: 5% of the total power can come from strings (see e.g. Dvorkin, Hu and Wyman, 2011, Planck collab., 2013). Leads to limit Gµ < / 62

32 19 / 62 Plan in Signature of s in High z Large-Scale Structure Surveys 5 of in 6 of in Maps 7 Effects of 8

33 20 / 62 Geometry of a Straight String A. Vilenkin, Phys. Rev. D 23, 852 (1981). Space away from the string is locally flat (cosmic string exerts no gravitational pull). Space perpendicular to a string is conical with deficit angle α = 8πGµ, in

34 21 / 62 Effect N. Kaiser and A., Nature 310, 391 (1984). Photons passing by the string undergo a relative Doppler shift δt T = 8πγ(v)vGµ, in

35 22 / 62 network of line discontinuities in anisotropy maps. N.B. characteristic scale: comoving Hubble radius at the time of recombination need good angular resolution to detect these edges. Need to analyze position space maps. in

36 23 / 62 Signature in temperature anisotropy maps R. J. Danos and R. H. Brandenberger, arxiv: [astro-ph] x 10 0 map of the sky at 1.5 resolution in

37 24 / 62 network of line discontinuities in anisotropy maps. Characteristic scale: comoving Hubble radius at the time of recombination need good angular resolution to detect these edges. Need to analyze position space maps. Edges produced by cosmic strings are masked by the background" noise. in

38 25 / 62 Temperature map Gaussian + strings in

39 in network of line discontinuities in anisotropy maps. Characteristic scale: comoving Hubble radius at the time of recombination need good angular resolution to detect these edges. Need to analyze position space maps. Edges produced by cosmic strings are masked by the background" noise. Edge detection algorithms: a promising way to search for strings Application of Canny edge detection algorithm to simulated data (SPT/ACT specification) limit Gµ < may be achievable [S. Amsel, J. Berger and R.B. (2007), A. Stewart and R.B. (2008), R. Danos and R.B. (2008)] 26 / 62

40 in network of line discontinuities in anisotropy maps. Characteristic scale: comoving Hubble radius at the time of recombination need good angular resolution to detect these edges. Need to analyze position space maps. Edges produced by cosmic strings are masked by the background" noise. Edge detection algorithms: a promising way to search for strings Application of Canny edge detection algorithm to simulated data (SPT/ACT specification) limit Gµ < may be achievable [S. Amsel, J. Berger and R.B. (2007), A. Stewart and R.B. (2008), R. Danos and R.B. (2008)] 26 / 62

41 27 / 62 Wake J. Silk and A. Vilenkin, Phys. Rev. Lett. 53, 1700 (1984). Consider a cosmic string moving through the primordial gas: Wedge-shaped region of overdensity 2 builds up behind the moving string: wake. in

42 Closer look at the wedge in Consider a string at time t i [t rec < t i < t 0 ] moving with velocity v s with typical curvature radius c 1 t i c 1 t i v 4!Gµtivs"s t i v s "s 28 / 62

43 29 / 62 Gravitational accretion onto a wake L. Perivolaropoulos, R.B. and A., Phys. Rev. D 41, 1764 (1990). in Initial overdensity gravitational accretion onto the wake. Accretion computed using the Zeldovich approximation. Focus on a mass shell a physical distance w(q, t) above the wake: w(q, t) = a(t) ( q ψ ), Gravitational accretion ψ grows. Turnaround: ẇ(q, t) = 0 determines q nl (t) and thus the thickness of the gravitationally bound region.

44 29 / 62 Gravitational accretion onto a wake L. Perivolaropoulos, R.B. and A., Phys. Rev. D 41, 1764 (1990). in Initial overdensity gravitational accretion onto the wake. Accretion computed using the Zeldovich approximation. Focus on a mass shell a physical distance w(q, t) above the wake: w(q, t) = a(t) ( q ψ ), Gravitational accretion ψ grows. Turnaround: ẇ(q, t) = 0 determines q nl (t) and thus the thickness of the gravitationally bound region.

45 30 / 62 Gravitational accretion onto a wake (ctd.) L. Perivolaropoulos, R.B. and A., Phys. Rev. D 41, 1764 (1990). Result: q nl (t) a(t). in

46 31 / 62 Plan in Signature of s in High z Large-Scale Structure Surveys 5 of in 6 of in Maps 7 Effects of 8

47 32 / 62 No Direct Effect of F. Duplessis and R.B., arxiv: [astro-ph.co]. in Model: wakes form and fragment into spherical clumps whose radius at time t equals the width of the wake at time t. Wake temperature obtained by conversion of infall kinetic energy into thermal energy. Halo temperature given by virialization of the energy in the clumps. Result: for z > 5, T < 700K for a value of Gµ = 10 7, too low for atomic cooling. no independent star formation in the clumps produced by wakes. Note: See B. Shlaer, A. Vilenkin and A. Loeb (arxiv: ) for a similar analysis for string loops.

48 33 / 62 Indirect Signal of Y. Omori, R.B., in preparation. in The presence of a string wake causes a displacement in the distribution of galaxies formed by the Gaussian fluctuations. N-body simulation of structure formation in a ΛCDM cosmology with the addition of a string wake. By eye the effect of the wake is visible at redshift of z = 3 for Gµ = Using adapted statistics the presence of string wakes should be visible for significantly smaller values of Gµ.

49 34 / 62 Distribution of galaxies at z = 0 for Gµ = in

50 35 / 62 Distribution of galaxies at z = 3 for Gµ = in

51 36 / 62 Plan in Signature of s in High z Large-Scale Structure Surveys 5 of in 6 of in Maps 7 Effects of 8

52 37 / 62 Signature in R. Danos, R.B. and G. Holder, arxiv: [astro-ph.co]. in Wake is a region of enhanced free electrons. photons emitted at the time of recombination acquire extra polarization when they pass through a wake. Statistically an equal strength of E-mode and B-mode polarization is generated. Consider photons which at time t pass through a string segment laid down at time t i < t. P Q 24π ( 3 ) 1/2σT fgµv s γ s 25 4π Ω B ρ c (t 0 )mp 1 ( ) 2 ( t 0 z(t) + 1 z(ti ) + 1 ) 1/2.

53 38 / 62 Signature in II Inserting numbers yields the result: P Q fgµv (z(t) + 1) 2 (z(t i ) + 1) 310 sγ s Ω 7 B Characteristic pattern in position space: in

54 Angular Power Spectrum of B-Mode from R.B., N. Park and G. Salton, arxiv: [astro-ph.co]. 39 / 62 in 1 C 2 Π Q quad 1 nw

55 Is B-mode the Holy Grail of Inflation? R.B., arxiv: [astro-ph.co]. in strings produce direct B-mode polarization. gravitational waves not the only source of primordial B-mode polarization. string loop oscillations produce a scale-invariant spectrum of primordial gravitational waves with a contribution to δt /T which is comparable to that induced by scalar fluctuations (see e.g. A. Albrecht, R.B. and N. Turok, 1986). a detection of gravitational waves through B-mode polarization is more likely to be a sign of something different than inflation. If the spectrum of gravitational waves is blue this would rule out standard inflation and confirm a prediction first made in the context of superstring theory (R.B., et al, 2006). 40 / 62

56 41 / 62 Plan in Signature of s in High z Large-Scale Structure Surveys 5 of in 6 of in Maps 7 Effects of 8

57 Motivation R.B., D. Danos, O. Hernandez and G. Holder, arxiv: ; O. Hernandez, Yi Wang, R.B. and J. Fong, arxiv: / 62 in 21 cm surveys: new window to map the high redshift universe, in particular the dark ages". strings produce nonlinear structures at high redshifts. These nonlinear structures will leave imprints in 21 cm maps. (Khatri & Wandelt, arxiv: , A. Berndsen, L. Pogosian & M. Wyman, arxiv: ) 21 cm surveys provide 3-d maps potentially more data than the. 21 cm surveys is a promising window to search for cosmic strings.

58 43 / 62 The Effect in 10 3 > z > 10: baryonic matter dominated by neutral H. Neutral H has hydrogen hyperfine absorption/emission line. radiation passing through a cold gas cloud will be partially absorbed by exciting a transition. A hot gas cloud will produce radiation by a de-excitation transition. redshift surveys map the density distribution of neutral H. surveys: method to probe baryonic matter distribution before the epoch of star formation (i.e. in the "dark ages").

59 44 / 62 The Effect (II) String wake is a nonlinear overdensity in the baryon distribution with special geometry which emits/absorbs radiation. Whether signal is emission/absorption depends on the temperature of the gas cloud. At high redshifts the strings dominate the nonlinear structure and hence will dominate the redshift maps. in

60 44 / 62 The Effect (II) String wake is a nonlinear overdensity in the baryon distribution with special geometry which emits/absorbs radiation. Whether signal is emission/absorption depends on the temperature of the gas cloud. At high redshifts the strings dominate the nonlinear structure and hence will dominate the redshift maps. in

61 44 / 62 The Effect (II) String wake is a nonlinear overdensity in the baryon distribution with special geometry which emits/absorbs radiation. Whether signal is emission/absorption depends on the temperature of the gas cloud. At high redshifts the strings dominate the nonlinear structure and hence will dominate the redshift maps. in

62 45 / 62 t in!v!v

63 46 / 62 Geometry of the signal in x c x 2 x 1 # t t 0 s 1 s 2 2t i t i!! 2 1! x x 2 1 "! x c

64 47 / 62 Frequency dispersion Frequency dispersion δν ν = 2sin(θ) tan(θ)hw c, in

65 48 / 62 Brightness temperature in Brightness temperature: Spin temperature: T b (ν) = T S ( 1 e τ ν ) + Tγ (ν)e τν, T S = 1 + x c 1 + x c T γ /T K T γ. T K : gas temperature in the wake, x c collision coefficient Relative brightness temperature: δt b (ν) = T b(ν) T γ (ν) 1 + z

66 49 / 62 in Optical depth: τ ν = 3c2 A 10 ( ν )N HI 4ν 2 k B T S 4 φ(ν), N HI column number density of hydrogen atoms. Line profile: φ(ν) = 1 δν for ν ɛ [ν 10 δν 2, ν 10 + δν 2 ],

67 49 / 62 in Optical depth: τ ν = 3c2 A 10 ( ν )N HI 4ν 2 k B T S 4 φ(ν), N HI column number density of hydrogen atoms. Line profile: φ(ν) = 1 δν for ν ɛ [ν 10 δν 2, ν 10 + δν 2 ],

68 Application to in Wake temperature T K : T K [20 K](Gµ) 2 6 (v sγ s ) 2 z i + 1 z + 1, determined by considering thermalization at the shock which occurs after turnaround when w = 1/2w max (see Eulerian hydro simulations by A. Sornborger et al, 1997). Thickness in redshift space: δν ν = 24π 15 Gµv sγ s ( zi + 1 ) 1/2( z(t) + 1 ) 1/ (Gµ) 6 (v s γ s ), using z i + 1 = 10 3 and z + 1 = 30 in the second line. 50 / 62

69 Application to in Wake temperature T K : T K [20 K](Gµ) 2 6 (v sγ s ) 2 z i + 1 z + 1, determined by considering thermalization at the shock which occurs after turnaround when w = 1/2w max (see Eulerian hydro simulations by A. Sornborger et al, 1997). Thickness in redshift space: δν ν = 24π 15 Gµv sγ s ( zi + 1 ) 1/2( z(t) + 1 ) 1/ (Gµ) 6 (v s γ s ), using z i + 1 = 10 3 and z + 1 = 30 in the second line. 50 / 62

70 51 / 62 Relative brightness temperature: in x c ( T γ ) δt b (ν) = [0.07 K] 1 (1 + z) 1/2 1 + x c T K 200mK for z + 1 = 30. Signal is emission if T K > T γ and absorption otherwise. Critical curve (transition from emission to absorption): (Gµ) (v 2 (z + 1)2 sγ s ) z i + 1

71 51 / 62 Relative brightness temperature: in x c ( T γ ) δt b (ν) = [0.07 K] 1 (1 + z) 1/2 1 + x c T K 200mK for z + 1 = 30. Signal is emission if T K > T γ and absorption otherwise. Critical curve (transition from emission to absorption): (Gµ) (v 2 (z + 1)2 sγ s ) z i + 1

72 51 / 62 Relative brightness temperature: in x c ( T γ ) δt b (ν) = [0.07 K] 1 (1 + z) 1/2 1 + x c T K 200mK for z + 1 = 30. Signal is emission if T K > T γ and absorption otherwise. Critical curve (transition from emission to absorption): (Gµ) (v 2 (z + 1)2 sγ s ) z i + 1

73 Scalings of various temperatures 500 T K in Top curve: (Gµ) 6 = 1, bottom curve: (Gµ) 6 = 0.3 z 52 / 62

74 Extension 1: Diffuse" O. Hernandez and R.B., arxiv: also form for T K < T g, but no shock heating The wakes are more dilute thicker but less dense. h w (t) TK <T g T g = h w (t) Tg=0 T K This allows the exploration of smaller values of Gµ. in 53 / 62

75 54 / 62 in T b ze20 K z i 3000 Red to 1000 Blue GΜ 6

76 55 / 62 Extension 2: M. Pagano and R.B., arxiv: (2012). string loops seed nonlinear objects at high redshift. Spherical accretion Average overdensity 64 (compared to 4 for a wake) higher brightness temperature! But: no string-specific geometrical signal harder to identify loop signals compared to wake signals. in

77 56 / 62 Plan in Signature of s in High z Large-Scale Structure Surveys 5 of in 6 of in Maps 7 Effects of 8

78 57 / 62 as Seeds for Globular Clusters A. Barton, R.B. and L. Lin., arxiv: (2015). in are nonlinear seeds at high redshifts. seed the accretion of compact dense objects at early times. Hypothesis: String are the Seeds which develop into Globular Clusters swept up into galaxies at late times. Explains why globular clusters are old, dense and distributed in the halo. Free parameter Gµ fixed by demanding that the peak in the mass distribution of objects seeded by string loops agrees with the peak of the observed mass function in the Milky Way.

79 57 / 62 as Seeds for Globular Clusters A. Barton, R.B. and L. Lin., arxiv: (2015). in are nonlinear seeds at high redshifts. seed the accretion of compact dense objects at early times. Hypothesis: String are the Seeds which develop into Globular Clusters swept up into galaxies at late times. Explains why globular clusters are old, dense and distributed in the halo. Free parameter Gµ fixed by demanding that the peak in the mass distribution of objects seeded by string loops agrees with the peak of the observed mass function in the Milky Way.

80 57 / 62 as Seeds for Globular Clusters A. Barton, R.B. and L. Lin., arxiv: (2015). in are nonlinear seeds at high redshifts. seed the accretion of compact dense objects at early times. Hypothesis: String are the Seeds which develop into Globular Clusters swept up into galaxies at late times. Explains why globular clusters are old, dense and distributed in the halo. Free parameter Gµ fixed by demanding that the peak in the mass distribution of objects seeded by string loops agrees with the peak of the observed mass function in the Milky Way.

81 57 / 62 as Seeds for Globular Clusters A. Barton, R.B. and L. Lin., arxiv: (2015). in are nonlinear seeds at high redshifts. seed the accretion of compact dense objects at early times. Hypothesis: String are the Seeds which develop into Globular Clusters swept up into galaxies at late times. Explains why globular clusters are old, dense and distributed in the halo. Free parameter Gµ fixed by demanding that the peak in the mass distribution of objects seeded by string loops agrees with the peak of the observed mass function in the Milky Way.

82 Number Results A. Barton, R.B. and L. Lin, arxiv: (2015) Histogram in log(m) Experimental Theoretical 58 / 62

83 as the Seeds for High Redshift Super-Massive Black Holes A. Barton, R.B., P. Jreidini and J. Quintin, arxiv: (2015). 59 / 62 Observations: More than 40 black holes at z > 6 and mass M > 10 9 M 0 discovered. It is challenging to explain the origin of the massive seeds with only standard Gaussian fluctuations. Hypothesis: String are the Seeds for the Accretion of high z super-massive black holes. in

84 as the Seeds for High Redshift Super-Massive Black Holes A. Barton, R.B., P. Jreidini and J. Quintin, arxiv: (2015). 59 / 62 Observations: More than 40 black holes at z > 6 and mass M > 10 9 M 0 discovered. It is challenging to explain the origin of the massive seeds with only standard Gaussian fluctuations. Hypothesis: String are the Seeds for the Accretion of high z super-massive black holes. in

85 as the Seeds for High Redshift Super-Massive Black Holes A. Barton, R.B., P. Jreidini and J. Quintin, arxiv: (2015). 59 / 62 Observations: More than 40 black holes at z > 6 and mass M > 10 9 M 0 discovered. It is challenging to explain the origin of the massive seeds with only standard Gaussian fluctuations. Hypothesis: String are the Seeds for the Accretion of high z super-massive black holes. in

86 as the Seeds for High Redshift Super-Massive Black Holes A. Barton, R.B., P. Jreidini and J. Quintin, arxiv: (2015). 59 / 62 Observations: More than 40 black holes at z > 6 and mass M > 10 9 M 0 discovered. It is challenging to explain the origin of the massive seeds with only standard Gaussian fluctuations. Hypothesis: String are the Seeds for the Accretion of high z super-massive black holes. in

87 M s (z i ) 60 / 62 Results A. Barton, R.B., P. Jreidini and J. Quintin, arxiv: (2015) Gaussian.uctuations G7 = 10!9:5 G7 = 10!12 G7 = 10! in z i 10 0

88 61 / 62 Plan in Signature of s in High z Large-Scale Structure Surveys 5 of in 6 of in Maps 7 Effects of 8

89 62 / 62 in strings nonlinearities already at high redshifts. of cosmic strings more pronounced at high redshifts. string wakes lead to perturbations which are non-gaussian. string wakes predict specific geometrical patterns in position space. 21 cm surveys provide an ideal arena to look for cosmic strings. string wakes produce distinct wedges in redshift space with enhanced absorption or emission.