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We study a possibility of constraining isotropic cosmic birefringence with help of cosmic microwave background polarisation data in the presence of polarisation angle miscalibration without relying on any assumptions about the Galactic…

宇宙学与河外天体物理 · 物理学 2023-12-13 Baptiste Jost , Josquin Errard , Radek Stompor

The cosmic microwave background (CMB), carrying the inhomogeneous information of the very early universe, is of great significance for understanding the origin and evolution of our universe. However, observational CMB maps contain serious…

宇宙学与河外天体物理 · 物理学 2022-05-12 Guo-Jian Wang , Hong-Liang Shi , Ye-Peng Yan , Jun-Qing Xia , Yan-Yun Zhao , Si-Yu Li , Jun-Feng Li

We present a multifrequency approach which optimizes the constraints on cosmological parameters with respect to extragalactic sources and secondary anisotropies contamination on small scales. We model with a minimal number of parameters the…

宇宙学与河外天体物理 · 物理学 2015-06-03 D. Paoletti , N. Aghanim , M. Douspis , F. Finelli , G. De Zotti , G. Lagache , Aurélie Pénin

We consider a cosmological model with non-Gaussian initial perturbations, which in principle could be generated in non-standard inflationary scenarios with two or more scalar fields. In particular we focus our attention on the model…

天体物理学 · 物理学 2011-05-10 Dmitri Novikov , Jens Schmalzing , Viatcheslav F. Mukhanov

We investigate the stochasticity in temperature fluctuations in the cosmic microwave background (CMB) radiation data from {\it Wilkinson Microwave Anisotropy Probe}. We show that the angular fluctuations of the temperature is a Markov…

Separating foregrounds from the signal is one of the big challenges in cosmic microwave background (CMB) experiments. A simple way to estimate the CMB temperature in a given pixel is to fit for the amplitudes of the CMB and the various…

天体物理学 · 物理学 2009-10-28 Scott Dodelson

We describe and discuss the application of Gumbel statistics, which model extreme events, to WMAP 5-year measurements of the cosmic microwave background. We find that temperature extrema of the CMB are well modelled by the Gumbel formalism…

宇宙学与河外天体物理 · 物理学 2015-06-01 Gatis Mikelsons , Joseph Silk , Joe Zuntz

In this paper, by cross-correlating an archive sample of 542 extragalactic radio sources with the \emph{Fermi}-LAT Third Source Catalog(3FGL), we have compiled a sample of 80 $\gamma$-ray sources and 462 non-\emph{Fermi} sources with…

星系天体物理 · 物理学 2016-08-17 Zhenkuo Liu , Zhongzu Wu , Minfeng Gu

A direct search of $\gamma$-ray emission centered on multi-frequency selected candidates is a valuable complementary approach to the standard search adopted in current $\gamma$-ray Fermi-LAT catalogs. Our candidates are part of the 2WHSP…

高能天体物理现象 · 物理学 2017-02-15 Bruno Arsioli , Yu-Ling Chang

The problem of the detection and mapping of a stochastic gravitational wave background (SGWB), either of cosmological or astrophysical origin, bears a strong semblance to the analysis of CMB anisotropy and polarization. The basic statistic…

广义相对论与量子宇宙学 · 物理学 2008-12-18 Sanjit Mitra , Sanjeev Dhurandhar , Tarun Souradeep , Albert Lazzarini , Vuk Mandic , Sukanta Bose , Stefan Ballmer

We report a measurement of anisotropy in the cosmic microwave background radiation (CMBR) on 7-22 arcminute scales. Observations of 36 fields near the North Celestial Pole (NCP) were made at 31.7 and 14.5 GHz, using the 5.5-meter and…

天体物理学 · 物理学 2007-05-23 E. M. Leitch , A. C. S. Readhead , T. J. Pearson , S. T. Myers , S. Gulkis , C. R. Lawrence

We present the results of a combined analysis of cosmic microwave background (CMB) and X-ray galaxy clusters baryon fraction to deduce constraints over 6 in flationnary cosmological parameters. Such a combination is necessary for breaki ng…

天体物理学 · 物理学 2007-05-23 M. Douspis , A. Blanchard , R. Sadat , J. G. Bartlett

We discuss the problem of CMB spectrum corruption during Galactic emission removing. A new technique of spatial--frequency data reduction is proposed. The technique gives us a possibility to avoid a spatial harmonics nonorthogonality. The…

天体物理学 · 物理学 2007-05-23 A. A. Brukhanov , D. P. Skulachev , I. A. Strukov , T. V. Konkina

We report an investigation of cosmological parameters based on the measurements of anisotropy in the cosmic microwave background radiation (CMB) made by ACBAR. We use the ACBAR data in concert with other recent CMB measurements to derive…

Density perturbations at the decoupling epoch produce angular fluctuations in the temperature of the Cosmic Microwave Background (CMB) radiation that may appear as hot and cold spots. Observational data of the CMB includes instrumental…

天体物理学 · 物理学 2009-10-28 Laura Cayon , George Smoot

We search the high-latitude portion of the COBE Differential Microwave Radiometers (DMR) 4-year sky maps for evidence of a non-Gaussian temperature distribution in the cosmic microwave background. The genus, 3-point correlation function,…

天体物理学 · 物理学 2009-10-28 A. Kogut , A. J. Banday , C. L. Bennett , K. Gorski , G. Hinshaw , G. F. Smoot , E. L. Wright

Since the temperature fluctuations in cosmic microwave background (CMB) on large-angular scales probe length scales that were super-horizon sized at photon decoupling and hence insensitive to microphysical processes, the low-multipole CMB…

宇宙学与河外天体物理 · 物理学 2015-12-30 Cheng Cheng , Qing-Guo Huang

We reanalyse Cosmic Microwave Background data from experiments probing both large and small scales. We assume that measured anisotropies are due not only to primary fluctuations but also, especially at small scales, to secondary effects…

天体物理学 · 物理学 2007-05-23 Marian Douspis , Nabila Aghanim , Mathieu Langer

The recent measurements of the power spectrum of Cosmic Microwave Background anisotropies are consistent with the simplest inflationary scenario and big bang nucleosynthesis constraints. However, these results rely on the assumption of a…

天体物理学 · 物理学 2009-11-07 Carolina J. Odman , Alessandro Melchiorri , Michael P. Hobson , Anthony N. Lasenby

ABSRACT: We review recent progress on testing the hypothesis of the existence of cosmic string perturbations in microwave background maps. Using an analytical model for the string network we show that the predicted amplitude and spectrum of…

天体物理学 · 物理学 2009-09-25 Leandros Perivolaropoulos , Richhild Moessner , Robert Brandenberger