Sex, Drugs and DNA

Stebbins, Michael

doi:10.1007/978-0-230-55226-5

Cited by 7 publications

(28 citation statements)

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“…The last term is the expression for the distortion, where y ≃ 7 10 ( /c) 2 dτ(γ ′ ) defines the effective y-parameter introduced by inhomogeneities ( Moss et al 2011). It was initially derived using the work of Stebbins (2007), but can also be obtained from second-order Doppler terms of the photon Boltzmann equation (e.g., Hu et al 1994;Nozawa et al 1998). The limits from COBE/FIRAS then imply | |/c 1.5 × 10 −2 for constant and τ ≃ 0.1 from WMAP (Komatsu et al 2011).…”

Section: Scattering Signals In the Thomson Limitmentioning

confidence: 99%

Tests of the CMB temperature-redshift relation, CMB spectral distortions and why adiabatic photon production is hard

Chluba

2014

Monthly Notices of the Royal Astronomical Society

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In the expanding Universe, the average temperature of the cosmic microwave background (CMB) is expected to depend like T CMB ∝ (1 + z) on redshift z. Adiabatic photon production (or destruction) or deviations from isotropy and homogeneity could modify this scaling and several observational tests have been carried out in response. Here, we explain why 'adiabatic' conditions are extremely difficult to establish in the redshift range targeted by these tests. Thus, instead of leading to a simple rescaling of the CMB temperature, a spectral distortion should be produced, which can be constrained using COBE/FIRAS. For scenarios with late photon production, tests of the temperature-redshift relation (TRR) should therefore be reinterpreted as weak spectral distortion limits, directly probing the energy dependence of the photon production process. For inhomogeneous cosmologies, an average y-type distortion is produced, but this type of distortion can be created in several other ways. Here, we briefly discuss possible effects that may help disentangling different contributions to the distortion signal, finding this to be very challenging. We furthermore argue that tests of the TRR, using the SZ effect have limited applicability and that for non-gravitational changes to the TRR the CMB anisotropy spectrum should exhibit an additional y-type dependence.

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Section: Scattering Signals In the Thomson Limitmentioning

confidence: 99%

Tests of the CMB temperature-redshift relation, CMB spectral distortions and why adiabatic photon production is hard

Chluba

2014

Monthly Notices of the Royal Astronomical Society

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“…Spectral distortions are thus an invaluable new source of information about earlyuniverse physics, which is complementary and independent of the directly observable CMB temperature and polarization anisotropies at larger angular scales. E-mail: jchluba@pha.jhu.edu † E-mail: ldai@pha.jhu.edu The distortion from primordial perturbations is created because the superposition of blackbodies at different temperatures is not itself a blackbody (Zeldovich et al 1972;Chluba & Sunyaev 2004;Stebbins 2007). A spatially varying photon field at different scales is set up by inflation and the mixing of blackbodies is accomplished by Thomson scattering.…”

Section: Introductionmentioning

confidence: 99%

Spectral distortions from the dissipation of tensor perturbations

Chluba¹,

Dai²,

Grin³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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Spectral distortions of the cosmic microwave background (CMB) may become a powerful probe of primordial perturbations at small scales. Existing studies of spectral distortions focus almost exclusively on primordial scalar metric perturbations. Similarly, vector and tensor perturbations should source CMB spectral distortions. In this paper, we give general expressions for the effective heating rate caused by these types of perturbations, including previously neglected contributions from polarization states and higher multipoles. We then focus our discussion on the dissipation of tensors, showing that for nearly scale invariant tensor power spectra, the overall distortion is some six orders of magnitudes smaller than from the damping of adiabatic scalar modes. We find simple analytic expressions describing the effective heating rate from tensors using a quasi-tight coupling approximation. In contrast to adiabatic modes, tensors cause heating without additional photon diffusion and thus over a wider range of scales, as recently pointed out by Ota et al. (2014). Our results are in broad agreement with their conclusions, but we find that small-scale modes beyond k 2 × 10 4 Mpc −1 cannot be neglected, leading to a larger distortion, especially for very blue tensor power spectra. At small scales, also the effect of neutrino damping on the tensor amplitude needs to be included.

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“…Spectral distortions are also sensitive to other processes at z ∼ < 10 6 , like dark matter annihilation/decay [69][70][71] or early star formation [42,72]. Missions like PIXIE and PRISM could open a window to measuring µ, y in detail and also detecting recombination-era line emission [73][74][75][76], motivating recent work on thermalization during this era [51,71,[77][78][79][80][81][82][83].…”

Section: Introductionmentioning

confidence: 99%

Probing early-universe phase transitions with CMB spectral distortions

Amin

Grin

2014

Phys. Rev. D

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Global, symmetry-breaking phase transitions in the early universe can generate scaling seed networks which lead to metric perturbations. The acoustic waves in the photon-baryon plasma sourced by these metric perturbations, when Silk damped, generate spectral distortions of the cosmic microwave background (CMB). In this work, the chemical potential distortion (µ) due to scaling seed networks is computed and the accompanying Compton y-type distortion is estimated. The specific model of choice is the O(N ) nonlinear σ-model for N 1, but the results remain the same order of magnitude for other scaling seeds. If CMB anisotropy constraints to the O(N ) model are saturated, the resulting chemical potential distortion µ 2 × 10 −9 .

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Sex, Drugs and DNA

Cited by 7 publications

References 0 publications

Tests of the CMB temperature-redshift relation, CMB spectral distortions and why adiabatic photon production is hard

Tests of the CMB temperature-redshift relation, CMB spectral distortions and why adiabatic photon production is hard

Spectral distortions from the dissipation of tensor perturbations

Probing early-universe phase transitions with CMB spectral distortions

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