2006 (IPP)
Permanent URI for this collectionhttp://localhost:4000/handle/11007/335
Browse
3 results
Search Results
Item Statistical isotropy of CMB polarization maps(2006-06-25) Basak, Soumen; Hajian, Amir; Souradeep, TarunWe formulate statistical isotropy of CMB anisotropy maps in its most general form. We also present a fast and orientation independent statistical method to determine deviations from statistical isotropy in CMB polarization maps. Importance of having statistical tests of departures from SI for CMB polarization maps lies not only in interesting theoretical motivations but also in testing cleaned CMB polarization maps for observational artifacts such as residuals from polarized foreground emission. We propose a generalization of the Bipolar Power Spectrum (BiPS) to polarization maps. Application to the observed CMB polarization maps will be soon possible after the release of WMAP three year data. As a demonstration we show that for E-polarization this test can detect breakdown of statistical isotropy due to polarized synchrotron foreground.Item Cosmology with CMB anisotropy(2006-07-12) Souradeep, TarunMeasurements of CMB anisotropy and, more recently, polarization have played a very important role allowing precise determination of various parameters of the ‘standard’ cosmological model. The expectation of the paradigm of inflation and the generic prediction of the simplest real- ization of inflationary scenario in the early universe have also been established – ‘acausally’ correlated initial perturbations in a flat, statistically isotropic universe, adiabatic nature of primordial density perturbations. Direct evidence for gravitational instability mechanism for structure formation from primordial perturbations has been established. In the next decade, future experiments promise to strengthen these deductions and uncover the remaining crucial signature of inflation – the primordial gravitational wave background.Item Cosmological quests in the CMB sky(2006-06-21) Souradeep, TarunObservational Cosmology has indeed made very rapid progress in recent years. The ability to quantify the universe has largely improved due to observational constraints coming from structure formation Measure- ments of CMB anisotropy and, more recently, polarization have played a very important role. Besides precise determination of various parameters of the ‘standard’ cosmological model, observations have also established some important basic tenets that underlie models of cosmology and struc- ture formation in the universe – ‘acausally’ correlated initial perturbations in a flat, statistically isotropic universe, adiabatic nature of primordial density perturbations. These are consistent with the expectation of the paradigm of inflation and the generic prediction of the simplest realization of inflationary scenario in the early universe. Further, gravitational instability is the established mechanism for structure formation from these initial perturbations. In the next decade, future experiments promise to strengthen these deductions and uncover the remaining crucial signature of inflation – the primordial gravitational wave background.