Search Publications
Estimation of inflation parameters for Perturbed Power Law model using recent CMB measurements
Das, Santanu; Souradeep, Tarun; Mukherjee, Suvodip +1 more
Cosmic Microwave Background (CMB) is an important probe for understanding the inflationary era of the Universe. We consider the Perturbed Power Law (PPL) model of inflation which is a soft deviation from Power Law (PL) inflationary model. This model captures the effect of higher order derivative of Hubble parameter during inflation, which in turn …
Constraining hybrid natural inflation with recent CMB data
Hidalgo, Juan Carlos; Vázquez, J. Alberto; Carrillo-González, Mariana +2 more
We study the Hybrid Natural Inflation (HNI) model and some of its realisations in the light of recent CMB observations, mainly Planck temperature and WMAP-9 polarization, and compare with the recent release of BICEP2 dataset. The inflationary sector of HNI is essentially given by the potential V(ϕ) = V0(1+acos(ϕ/f)), where a is a positi…
Unveiling acoustic physics of the CMB using nonparametric estimation of the temperature angular power spectrum for Planck
Shafieloo, Arman; Aghamousa, Amir; Souradeep, Tarun +1 more
Estimation of the angular power spectrum is one of the important steps in Cosmic Microwave Background (CMB) data analysis. Here, we present a nonparametric estimate of the temperature angular power spectrum for the Planck 2013 CMB data. The method implemented in this work is model-independent, and allows the data, rather than the model, to dictate…
Planck data and ultralight axions
Csáki, Csaba; Kaloper, Nemanja; Terning, John
We examine the effects of photon-axion mixing on the CMB. We show that if there are very underdense regions between us and the last scattering surface which contain coherent magnetic fields (whose strength can be orders of magnitude weaker than the current bounds), then photon-axion mixing can induce observable deviations in the CMB spectrum. Spec…
The morphology of the Anomalous Microwave Emission in the Planck 2015 data release
Liu, Hao; von Hausegger, Sebastian
We calculate weighted mosaic correlations between the recently published Planck 2015 foreground maps- both anomalous microwave emission (AME) maps, free-free emission, synchrotron radiation and thermal dust emission. The weighting coefficients are constructed taking account of the signal-to-error ratio given by the data product. Positive correlati…
Nonparametric test of consistency between cosmological models and multiband CMB measurements
Shafieloo, Arman; Aghamousa, Amir
We present a novel approach to test the consistency of the cosmological models with multiband CMB data using a nonparametric approach. In our analysis we calibrate the REACT (Risk Estimation and Adaptation after Coordinate Transformation) confidence levels associated with distances in function space (confidence distances) based on the Monte Carlo …
Learn-as-you-go acceleration of cosmological parameter estimates
Aslanyan, Grigor; Easther, Richard; Price, Layne C.
Cosmological analyses can be accelerated by approximating slow calculations using a training set, which is either precomputed or generated dynamically. However, this approach is only safe if the approximations are well understood and controlled. This paper surveys issues associated with the use of machine-learning based emulation strategies for ac…
Simulations of cm-wavelength Sunyaev-Zel'dovich galaxy cluster and point source blind sky surveys and predictions for the RT32/OCRA-f and the Hevelius 100-m radio telescope
Birkinshaw, Mark; Lew, Bartosz; Wilkinson, Peter +1 more
We investigate the effectiveness of blind surveys for radio sources and galaxy cluster thermal Sunyaev-Zel'dovich effects (TSZEs) using the four-pair, beam-switched OCRA-f radiometer on the 32-m radio telescope in Poland. The predictions are based on mock maps that include the cosmic microwave background, TSZEs from hydrodynamical simulations of l…
Revised cosmological parameters after BICEP 2 and BOSS
Das, Santanu; Souradeep, Tarun; Mukherjee, Suvodip
Estimation of parameters of the 'standard' model of cosmology have dramatically improved over past few decades due to increasingly exquisite measurements made by Cosmic Microwave Background (CMB) experiments. Recent data from Planck matches well with the minimal ΛCDM model. A likelihood analysis using Planck, WMAP and a selection of high resolutio…
Subdominant Dark Matter sterile neutrino resonant production in the light of PLANCK
Popa, L. A.; Tonoiu, D.
Few independent detections of a weak X-ray line at an energy of ~ 3.5 keV seen toward a number of astrophysical sites have been reported. If this signal will be confirmed to be the signature of decaying DM sterile neutrino with a mass of ~ 7.1 keV, then the cosmological observables should be consistent with its properties.