ترغب بنشر مسار تعليمي؟ اضغط هنا

Small Scale Fluctuations of the Microwave Background in the Quasi-Steady State Cosmology

44   0   0.0 ( 0 )
 نشر من قبل Vishwakarma R. G.
 تاريخ النشر 2001
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

In this paper we show that, within the framework of the QSSC, the small scale deviations on angular scales $lesssim 1^{0}$ expected in the MBR are due to inhomogeneities in the distribution of galaxies and clusters. It is shown how these can be estimated on the galaxy-cluster-supercluster scale at the epoch of redshift $sim 5$ when the universe was last passing through the minimum phase of the scale factor. Rich clusters on the scale of 5-10 Mpc generate the kind of peak in the fluctuation power spectrum observed by the Boomrang and Maxima projects. Weaker inhomogeneities on smaller scales with $l~sim 10^3$ are expected to arise from individual galaxies and small groups.



قيم البحث

اقرأ أيضاً

We calculate the expected angular power spectrum of the temperature fluctuations in the microwave background radiation (MBR) generated in the quasi-steady state cosmology (QSSC). The paper begins with a brief description of how the background is prod uced and thermalized in the QSSC. We then discuss within the framework of a simple model, the likely sources of fluctuations in the background due to astrophysical and cosmological causes. Power spectrum peaks at $l approx 6-10$, 180-220 and 600-900 are shown to be related in this cosmology respectively to curvature effects at the last minimum of the scale factor, clusters and groups of galaxies. The effect of clusters is shown to be related to their distribution in space as indicated by a toy model of structure formation in the QSSC. We derive and parameterize the angular power spectrum using six parameters related to the sources of temperature fluctuations at three characteristic scales. We are able to obtain a satisfactory fit to the observational band power estimates of MBR temperature fluctuation spectrum. Moreover, the values of `best fit parameters are consistent with the range of expected values.
68 - G. Burbidge 2001
A brief historical account of modern cosmology shows that the standard big bang (BB) model, believed by so many, does not have the strong observational foundations that are frequently claimed for it. The theory of the Quasi-Steady State Cosmology (QS SC) and explosive cosmogony is outlined. Comparisons are made between the two theories in explaining the observed properties of the universe, namely, the expansion, chemical composition, CMB, QSO redshifts and explosive events, galaxy formation, and the m-z and theta-z relations. Only two of the observed properties have ever been predicted from the theories (a) the expansion predicted from Einsteins theory by Friedmann and Lemaitre, and (b) the acceleration predicted by the classical steady state theory and the QSSC.
94 - X. Dupac 2007
We present the main scientific goals and characteristics of the ESA Planck satellite mission, as well as the main features of the survey strategy and simulated performance in terms of measuring the temperature and polarization of the Cosmic Microwave Background fluctuations.
Cosmic string networks generate cosmological perturbations actively throughout the history of the universe. Thus, the string sourced anisotropy of the cosmic microwave background is not affected by Silk damping as much as the anisotropy seeded by inf lation. The spectrum of perturbations generated by strings does not match the observed CMB spectrum on large angular scales (l<1000) and is bounded to contribute no more than 10% of the total power on those scales. However, when this bound is marginally saturated, the anisotropy created by cosmic strings on small angular scales l>2000 will dominate over that created by the primary inflationary perturbations. This range of angular scales in the CMB is presently being measured by a number of experiments; their results will test this prediction of cosmic string networks soon.
Fluctuations in the brightness of the Earths atmosphere originating from water vapor are an important source of noise for ground-based instruments attempting to measure anisotropy in the Cosmic Microwave Background. This paper presents a model for th e atmospheric fluctuations and derives simple expressions to predict the contribution of the atmosphere to experimental measurements. Data from the South Pole and from the Atacama Desert in Chile, two of the driest places on Earth, are used to assess the level of fluctuations at each site.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا