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We constrain the primordial fluctuation spectrum P(k) by using the new data on the Cosmic Microwave Background (CMB) from the Boomerang and MAXIMA experiments. Our study is based on slow-roll inflationary models, and we consider the…

天体物理学 · 物理学 2009-10-31 S. Hannestad , S. H. Hansen , F. L. Villante

The enormous red-shifting of the modes during the inflationary epoch suggests that physics at the very high energy scales may modify the primordial perturbation spectrum. Therefore, the measurements of the anisotropies in the Cosmic…

高能物理 - 理论 · 物理学 2015-06-26 S. Shankaranarayanan , L. Sriramkumar

The temperature fluctuations and polarization of the Cosmic Microwave Background (CMB) are now a well-known probe of the Universe at an infant age of 400,000 years. During the transit to us from the surface of last scattering, the CMB…

宇宙学与河外天体物理 · 物理学 2011-04-19 Joseph Smidt , Asantha Cooray , Alexandre Amblard , Shahab Joudaki , Dipak Munshi , Mario G. Santos , Paolo Serra

We develop a new method to reconstruct the power spectrum of primordial curvature perturbations, $P(k)$, by using both the temperature and polarization spectra of the cosmic microwave background (CMB). We test this method using several mock…

天体物理学 · 物理学 2009-10-09 Noriyuki Kogo , Misao Sasaki , Jun'ichi Yokoyama

Both the Wilkinson Microwave Anisotropy Probe (WMAP) and Planck observations reported the hemispherical asymmetry of the cosmic microwave background (CMB) temperature fluctuation. The hemispherical asymmetry might be stemmed from the…

宇宙学与河外天体物理 · 物理学 2014-05-13 Zhe Chang , Sai Wang

We investigate inflationary scenarios driven by a class of potentials which are similar in form to those that arise in certain minimal supersymmetric extensions of the standard model. We find that these potentials allow a brief period of…

天体物理学 · 物理学 2014-11-18 Rajeev Kumar Jain , Pravabati Chingangbam , Jinn-Ouk Gong , L. Sriramkumar , Tarun Souradeep

The temperature perturbations of the cosmic microwave background radiation (CMB) appear systematically suppressed, at large angular scales, with respect to the prediction of the LambdaCDM concordance model. This behavior might be a glimpse…

宇宙学与河外天体物理 · 物理学 2019-08-14 Noriaki Kitazawa

Cosmic microwave background (CMB) experiments generally infer a temperature fluctuation from a measured intensity fluctuation through the first term in the Taylor expansion of the Planck function, the relation between the intensity in a…

天体物理学 · 物理学 2009-11-07 M. Kamionkowski , Lloyd Knox

The CMB temperature power spectrum offers ambiguous evidence for the existence of horizon-scale power in the primordial power spectrum due to uncertainties in spatial curvature and the physics of cosmic acceleration as well as the observed…

宇宙学与河外天体物理 · 物理学 2009-07-30 Michael J. Mortonson , Wayne Hu

The lowest multipole moments of the cosmic microwave background (CMB) are smaller than expected for a scale-invariant power spectrum. One possible explanation is a cutoff in the primordial power spectrum below a comoving scale of $k_c…

天体物理学 · 物理学 2009-11-10 Michael Kesden , Marc Kamionkowski , Asantha Cooray

The largest fluctuation in the observed CMB temperature field is the dipole, its origin being usually attributed to the Doppler Effect - the Earth's velocity with respect to the CMB rest frame. The lowest order boost correction to…

宇宙学与河外天体物理 · 物理学 2010-09-28 Thiago S. Pereira , Amanda Yoho , Maik Stuke , Glenn D. Starkman

We reconsider trans-Planckian corrections to inflationary spectra by taking into account a physical effect which has been overlooked and which could have important consequences. We assume that the short length scale characterizing the new…

高能物理 - 理论 · 物理学 2008-11-26 David Campo , Jens Niemeyer , Renaud Parentani

We examine the contribution of tensor modes, in addition to the dominant scalar ones, on the temperature anisotropies of the cosmic microwave background (CMB). To this end, we analyze in detail the temperature two-point angular correlation…

宇宙学与河外天体物理 · 物理学 2023-12-06 Miguel-Angel Sanchis-Lozano , Veronica Sanz

The recent observations of cross temperature-polarization power spectra of the Cosmic Microwave Background (CMB) made by the WMAP satellite are in better agreement with a high value of the Thomson scattering optical depth \tau \approx 0.17.…

天体物理学 · 物理学 2009-11-13 A. Melchiorri , T. Roy Choudhury , P. Serra , A. Ferrara

Mainly used to set constraints on cosmological parameters, CMB anisotropies can give information on primordial universe. Unfortunately, initial conditions and late time cosmology are degenerated. I focus on the effect of the shape of the…

天体物理学 · 物理学 2007-05-23 Marian Douspis

The small-scale crisis, discrepancies between observations and N-body simulations, may imply suppressed matter fluctuations on subgalactic distance scales. Such a suppression could be caused by some early-universe mechanism (e.g., broken…

宇宙学与河外天体物理 · 物理学 2017-07-05 Tomohiro Nakama , Jens Chluba , Marc Kamionkowski

We confront predictions of inflationary scenarios with the WMAP data, in combination with complementary small-scale CMB measurements and large-scale structure data. The WMAP detection of a large-angle anti-correlation in the…

The lack of large-angle correlations in the fluctuations of the cosmic microwave background (CMB) conflicts with predictions of slow-roll inflation. But though probabilities (< 0.24%) for the missing correlations disfavor the conventional…

宇宙学与河外天体物理 · 物理学 2018-03-14 Fulvio Melia , Martin Lopez-Corredoira

The power spectrum of the cosmic microwave background from both the Planck and WMAP data exhibits a slight dip in for multipoles in the range of l=10-30. We show that such a dip could be the result of resonant creation of a massive particle…

宇宙学与河外天体物理 · 物理学 2015-12-23 G. J. Mathews , M. R. Gangopadhyay , K. Ichiki , T. Kajino

We explicate the origin of the temperature quadrupole in the adiabatic dark energy model and explore the mechanism by which scale invariant isocurvature dark energy perturbations can lead to its sharp suppression. The model requires…

天体物理学 · 物理学 2011-05-12 Christopher Gordon , Wayne Hu