Model independent foreground power spectrum estimation using WMAP 5-year data (2009)
Ghosh, Tuhin, Saha, Rajib, Jain, Pankaj, Souradeep, Tarun
In this paper, we propose and implement on WMAP 5 yr data a model independent approach of foreground power spectrum estimation for multifrequency observations of the CMB experiments. Recently, a...
The tensor-to-scalar ratio in punctuated inflation (2009)
Jain, Rajeev Kumar, Chingangbam, Pravabati, Sriramkumar, L., Souradeep, Tarun
Scalar spectra which exhibit a sharp drop in power at length scales corresponding to the Hubble radius today are known to lead to a better fit of the observed Cosmic Microwave Background (CMB)...
Mitra, Sanjit, Sengupta, Anand S., Ray, Subharthi, Saha, Rajib, Souradeep, Tarun
Over the last decade, measurements of the cosmic microwave background (CMB) anisotropy have spearheaded the remarkable transition of cosmology into a precision science. However, addressing the...
Samal, Pramoda Kumar, Saha, Rajib, Delabrouille, Jacques, Prunet, Simon, Jain, Pankaj, Souradeep, Tarun
We estimate CMB polarization and temperature power spectra using WMAP 5-year foreground contaminated maps. The power spectrum is estimated by using a model independent method, which does not utilize...
Model Independent Foreground Power Spectrum Estimation using WMAP 5-year Data (2009)
Ghosh, Tuhin, Saha, Rajib, Jain, Pankaj, Souradeep, Tarun
In this paper, we propose & implement on WMAP 5-year data, a model independent approach of foreground power spectrum estimation for multifrequency observations of CMB experiments. Recently a model...
Assumptions of the primordial spectrum and cosmological parameter estimation (2009)
Shafieloo, Arman, Souradeep, Tarun
The observables of the perturbed universe, CMB anisotropy and large structures, depend on a set of cosmological parameters, as well as, the assumed nature of primordial perturbations. In particular,...
Punctuated inflation and the low CMB multipoles (2008)
Jain, Rajeev Kumar, Chingangbam, Pravabati, Gong, Jinn-Ouk, Sriramkumar, L., Souradeep, Tarun
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...
Gravitational wave radiometry: Mapping a stochastic gravitational wave background (2008)
Mitra, Sanjiv, Dhurandhar, Sanjeev, Souradeep, Tarun, Lazzarini, Albert, Mandic, Vuk, Bose, Sukanta, ...
The problem of the detection and mapping of a stochastic gravitational wave background (SGWB), either cosmological or astrophysical, bears a strong semblance to the analysis of the cosmic microwave...
Estimation of Primordial Spectrum with post-WMAP 3 year data (2007)
Shafieloo, Arman, Souradeep, Tarun
In this paper we implement an improved (error sensitive) Richardson-Lucy deconvolution algorithm on the measured angular power spectrum from the WMAP 3 year data to determine the primordial power...
Gravitational wave radiometry: Mapping a stochastic gravitational wave background (2007)
Mitra, Sanjit, Dhurandhar, Sanjeev, Souradeep, Tarun, Lazzarini, Albert, Mandic, Vuk, Bose, Sukanta, ...
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...
CMB anisotropy power spectrum using linear combinations of WMAP maps (2007)
Saha, Rajib, Prunet, Simon, Jain, Pankaj, Souradeep, Tarun
In recent years the goal of estimating different cosmological parameters precisely has set new challenges in the effort to accurately measure the angular power spectrum of CMB. This has required...
CMB power spectrum estimation with non-circular beam and incomplete sky coverage (2007)
Mitra, Sanjit, Sengupta, Anand S., Ray, Subharthi, Saha, Rajib, Souradeep, Tarun
Over the last decade, measurements of the CMB anisotropy has spearheaded the remarkable transition of cosmology into a precision science. However, addressing the systematic effects in the...
Features in the Primordial Spectrum from WMAP: A Wavelet Analysis (2006)
Shafieloo, Arman, Souradeep, Tarun, Manimaran, P., Panigrahi, Prasanta K., Rangarajan, Raghavan
Precise measurements of the anisotropies in the cosmic microwave background enable us to do an accurate study on the form of the primordial power spectrum for a given set of cosmological parameters....
Spectroscopy of Cosmic topology (2006)
Einstein's theory of gravitation that governs the geometry of space-time, coupled with spectacular advance in cosmological observations, promises to deliver a `standard model' of cosmology in the...
Non-Circular beam correction to the CMB power spectrum (2006)
Souradeep, Tarun, Mitra, Sanjit, Sengupta, Anand, Ray, Subharthi, Saha, Rajib
In the era of high precision CMB measurements, systematic effects are beginning to limit the ability to extract subtler cosmological information. The non-circularity of the experimental beam has...
Angular power spectrum of CMB anisotropy from WMAP (2006)
Souradeep, Tarun, Saha, Rajib, Jain, Pankaj
The remarkable improvement in the estimates of different cosmological parameters in recent years has been largely spearheaded by accurate measurements of the angular power spectrum of Cosmic...
Measuring Statistical Isotropy of CMB Anisotropy (2006)
Souradeep, Tarun, Hajian, Amir, Basak, Soumen
The statistical expectation values of the temperature fluctuations and polarization of cosmic microwave background (CMB) are assumed to be preserved under rotations of the sky. We investigate the...
Cosmology with CMB anisotropy (2006)
Measurements 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...
Hajian, Amir, Souradeep, Tarun
We examine statistical isotropy of large scale anisotropies of the Internal Linear Combination (ILC) map, based on three year WMAP data. Our study reveals no significant deviation from statistical...
Cosmological quests in the CMB sky (2006)
Observational 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...
Unveiling Hidden Patterns in CMB Anisotropy Maps (2006)
Ghosh, Tuhin, Hajian, Amir, Souradeep, Tarun
Bianchi VII_h models have been recently proposed to explain potential anomalies in the CMB anisotropy as observed by WMAP. We investigate the violation of statistical isotropy due to an embedded...
Statistical Isotropy of CMB Polarization Maps (2006)
Basak, Soumen, Hajian, Amir, Souradeep, Tarun
We 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...
Post-WMAP Assessment of Infrared Cutoff in the Primordial Spectrum from Inflation (2005)
The recent Cosmic Microwave Background (CMB) measurements indicate that there is power deficiency of the CMB anisotropies at large scales compared with the $\Lambda$CDM model. We have investigated...
A blind estimation of the power spectrum of CMB anisotropy from WMAP (2005)
Saha, Rajib, Jain, Pankaj, Souradeep, Tarun
Accurate measurements of angular power spectrum of Cosmic Microwave Background (CMB) radiation has lead to marked improvement in the estimates of different cosmological parameters. This has required...
Statistical isotropy of CMB anisotropy from WMAP (2005)
Souradeep, Tarun, Hajian, Amir
The statistical expectation values of the temperature fluctuations of cosmic microwave background (CMB) are assumed to be preserved under rotations of the sky. We investigate the statistical isotropy...
Summary of ICGC04 Cosmology Workshop (2005)
Cosmology is passing through a golden phase of rapid advance. The cosmology workshop at ICGC-2004 attracted a large number of research contributions from diverse topics of cosmology. I attempt to...
The Cosmic Microwave Background Bipolar Power Spectrum: Basic Formalism and Applications (2004)
Hajian, Amir, Souradeep, Tarun
We study the statistical isotropy (SI) of temperature fluctuations of the CMB as distinct from Gaussianity. We present a detailed formalism of the bipolar power spectrum (BiPS) which was introduced...
The current status of observational cosmology (2004)
Ostriker, Jeremiah P., Souradeep, Tarun
Observational 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...
Hajian, Amir, Souradeep, Tarun, Cornish, Neil
The statistical expectation values of the temperature fluctuations of the Cosmic Microwave Background (CMB) are assumed to be preserved under rotations of the sky. We investigate the Statistical...
Primordial power spectrum from WMAP (2003)
Shafieloo, Arman, Souradeep, Tarun
The observed angular power spectrum of the cosmic microwave background temperature anisotropy, $C_l$, is a convolution of a cosmological radiative transport kernel with an assumed primordial power...
Measuring Statistical isotropy of the CMB anisotropy (2003)
Hajian, Amir, Souradeep, Tarun
The statistical expectation values of the temperature fluctuations of cosmic microwave background (CMB) are assumed to be preserved under rotations of the sky. This assumption of {\em statistical...
Statistical isotropy of the Cosmic Microwave Background (2003)
Souradeep, Tarun, Hajian, Amir
The breakdown of statistical homogeneity and isotropy of cosmic perturbations is a generic feature of ultra large scale structure of the cosmos, in particular, of non trivial cosmic topology. The...
Galactic Foreground Constraints from the Python V Cosmic Microwave Background Anisotropy Data (2003)
Mukherjee, Pia, Coble, Kim, Dragovan, Mark, Ganga, Ken, Kovac, John, Ratra, Bharat, ...
We constrain Galactic foreground contamination of the Python V cosmic microwave background anisotropy data by cross correlating it with foreground contaminant emission templates. To model foreground...
Statistical Isotropy of CMB and Cosmic Topology (2003)
Hajian, Amir, Souradeep, Tarun
The breakdown of statistical homogeneity and isotropy of cosmic perturbations is a generic feature of ultra large scale structure of the cosmos, in particular, of non trivial cosmic topology. The...
Narlikar, J. V., Vishwakarma, R. G., Hajian, Amir, Souradeep, Tarun, Burbidge, G., Hoyle, F.
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...
Mukherjee, Pia, Ganga, Ken, Ratra, Bharat, Rocha, Graca, Souradeep, Tarun, Sugiyama, Naoshi, ...
We use joint likelihood analyses of combinations of fifteen cosmic microwave background (CMB) anisotropy data sets from the DMR, UCSB South Pole 1994, Python I--III, ARGO, MAX 4 and 5, White Dish,...
OVRO CMB Anisotropy Measurement Constraints on Flat-Lambda and Open CDM Cosmogonies (2002)
Mukherjee, Pia, Souradeep, Tarun, Ratra, Bharat, Sugiyama, Naoshi, Górski, Krzysztof M.
We use Owens Valley Radio Observatory (OVRO) cosmic microwave background (CMB) anisotropy data to constrain cosmological parameters. We account for the OVRO beamwidth and calibration uncertainties,...
Relic Gravity Waves from Braneworld Inflation (2001)
Sahni, Varun, Sami, M., Souradeep, Tarun
We discuss a scenario in which extra dimensional effects allow a scalar field with a steep potential to play the dual role of the inflaton as well as dark energy (quintessence). The post-inflationary...
Window Function for Non-Circular Beam CMB Anisotropy Experiment (2001)
Souradeep, Tarun, Ratra, Bharat
We develop computationally rapid methods to compute the window function for a cosmic microwave background anisotropy experiment with a non-circular beam which scans over large angles on the sky. To...
Binned Cosmic Microwave Background Anisotropy Power Spectra: Peak Location (2001)
Podariu, Silviu, Souradeep, Tarun, Gott III, J. Richard, Ratra, Bharat, Vogeley, Michael S.
We use weighted mean and median statistics techniques to combine individual cosmic microwave background (CMB) anisotropy detections and determine binned, multipole-space, CMB anisotropy power...
Tree structure of the percolating Universe (2000)
Colombi, Stephane, Pogosyan, Dmitry, Souradeep, Tarun
We present a numerical study of topological descriptors of initially Gaussian and scale-free density perturbations evolving via gravitational instability in an expanding universe. We carefully...
CMB Anisotropy in Compact Hyperbolic Universes I: Computing Correlation Functions (1999)
Bond, J. Richard, Pogosyan, Dmitry, Souradeep, Tarun
CMB anisotropy measurements have brought the issue of global topology of the universe from the realm of theoretical possibility to within the grasp of observations. The global topology of the...
CMB Anisotropy in Compact Hyperbolic Universes II: COBE Maps and Limits (1999)
Bond, J. Richard, Pogosyan, Dmitry, Souradeep, Tarun
We calculate the CMB anisotropy in compact hyperbolic universe models using the regularized method of images described in paper-I, including the 'line-of-sight `integrated Sachs-Wolfe' effect, as...
Computing CMB Anisotropy in Compact Hyperbolic Spaces (1998)
Bond, J. Richard, Pogosyan, Dmitri, Souradeep, Tarun
The measurements of CMB anisotropy have opened up a window for probing the global topology of the universe on length scales comparable to and beyond the Hubble radius. For compact topologies, the two...
Probing Cosmic topology using CMB anisotropy (1998)
Souradeep, Tarun, Pogosyan, Dmitry, Bond, J. Richard
The measurements of CMB anisotropy have opened up a window for probing the global topology of the universe on length scales comparable to and beyond the Hubble radius. We have developed a new method...
Prospects for measuring Inflation parameters with the CMB (1998)
Souradeep, Tarun, Bond, J. Richard, Knox, Lloyd, Efstathiou, George, Turner, Michael S.
We present the status of our study into the feasibility of estimating the parameters of inflation from planned satellite observations of the anisotropy of the cosmic microwave background (CMB).We...
Bharadwaj, Somnath, Munshi, Dipak, Souradeep, Tarun
In the context of inflationary scenarios, the observed large angle anisotropy of the Cosmic Microwave Background (CMB) temperature is believed to probe the primordial metric perturbations from...
Constraints on Compact Hyperbolic Spaces from COBE (1997)
Bond, J. Richard, Pogosyan, Dmitry, Souradeep, Tarun
The (large angle) COBE DMR data can be used to probe the global topology of our universe on scales comparable to and just beyond the present ``horizon''. For compact topologies, the two main effects...
Munshi, Dipak, Souradeep, Tarun, Starobinsky, Alexei A.
Skewness of temperature fluctuations of the cosmic microwave background (CMB) produced by initially Gaussian adiabatic perturbations with the flat (Harrison-Zeldovich) spectrum, which arises due to...
Post-COBE predictions for Inflationary Gravity Wave and Density Perturbation spectra (1993)
Sahni, Varun, Souradeep, Tarun
We assess the relative contribution to the COBE - measured microwave anisotropy arising both from relic gravity waves as well as primordial density perturbations originating during inflation. We show...
Generation of seed perturbations from Quantum Cosmology (1992)
The origin of seed perturbations in the Universe is studied within the framework of a specific minisuperspace model. It is shown that the `creation' of the Universe as a result of a quantum...
Quantum effects near a point mass in 2+1 dimensional gravity (1992)
Souradeep, Tarun, Sahni, Varun
We investigate the behaviour of classical and quantum fields in the conical space-time associated with a point mass in 2+1 dimensions. We show that the presence of conical boundary conditions alters...
Density Perturbations,Gravity Waves and the Cosmic Microwave Background (1992)
Souradeep, Tarun, Sahni, Varun
We asses the contribution to the observed large scale anisotropy of the cosmic microwave background radiation, arising from both gravity waves as well as adiabatic density perturbations, generated by...