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July - December 2014

Visibility-based angular power spectrum estimation in low-frequency radio interferometric observations

Choudhuri, Samir; Bharadwaj, Somnath; Ghosh, Abhik; Ali, Sk. Saiyad

We present two estimators to quantify the angular power spectrum of the sky signal directly from the visibilities measured in radio interferometric observations. This is relevant for both the foregrounds and the cosmological 21-cm signal buried ther ...
Statistical computation of Boltzmann entropy and estimation of the optimal probability density function from statistical sample

Sui, Ning; Li, Min; He, Ping

In this work, we investigate the statistical computation of the Boltzmann entropy of statistical samples. For this purpose, we use both histogram and kernel function to estimate the probability density function of statistical samples. We find that, ...
Reliable inference of exoplanet light-curve parameters using deterministic and stochastic systematics models

Gibson, N. P.

Time series photometry and spectroscopy of transiting exoplanets allow us to study their atmospheres. Unfortunately, the required precision to extract atmospheric information surpasses the design specifications of most general purpose instrumentatio ...
A Bayesian method for detecting stellar flares

Pitkin, M.; Williams, D.; Fletcher, L.; Grant, S. D. T.

We present a Bayesian-odds-ratio-based algorithm for detecting stellar flares in light-curve data. We assume flares are described by a model in which there is a rapid rise with a half-Gaussian profile, followed by an exponential decay. Our signal mo ...
A close examination of cosmic microwave background mirror-parity after Planck

Ben-David, Assaf; Kovetz, Ely D.

Previous claims of significant evidence for mirror-parity in the large-scale cosmic microwave background (CMB) data from the Wilkinson Microwave Anisotropy Probe (WMAP) experiment have been recently echoed in the first study of isotropy and statisti ...
The Eb Factory Project. Ii. Validation With the Kepler Field in Preparation for K2 and Tess

Parvizi, Mahmoud; Paegert, Martin; Stassun, Keivan G.

Large repositories of high precision light curve data, such as the Kepler data set, provide the opportunity to identify astrophysically important eclipsing binary (EB) systems in large quantities. However, the rate of classical “by eye” human an ...
Hierarchical analysis of the quiet-Sun magnetism

Asensio Ramos, A.; Martínez González, M. J.

Standard statistical analysis of the magnetic properties of the quiet Sun rely on simple histograms of quantities inferred from maximum-likelihood estimations. Because of the inherent degeneracies, either intrinsic or induced by the noise, this appr ...
A method for the estimation of the significance of cross-correlations in unevenly sampled red-noise time series

Max-Moerbeck, W.; Richards, J. L.; Hovatta, T.; Pavlidou, V.; Pearson, T. J.; Readhead, A. C. S.

We present a practical implementation of a Monte Carlo method to estimate the significance of cross-correlations in unevenly sampled time series of data, whose statistical properties are modelled with a simple power-law power spectral density. This ...
Features in the broad-band eclipse spectra of exoplanets: signal or noise?

Hansen, Christopher J.; Schwartz, Joel C.; Cowan, Nicolas B.

A planet's emission spectrum contains information about atmospheric composition and structure. We compare the Bayesian Information Criterion (BIC) of blackbody fits and idealized spectral retrieval fits for the 44 planets with published eclipse meas ...
BayeSED: A General Approach to Fitting the Spectral Energy Distribution of Galaxies

Han, Yunkun; Han, Zhanwen

We present a newly developed version of BayeSED, a general Bayesian approach to the spectral energy distribution (SED) fitting of galaxies. The new BayeSED code has been systematically tested on a mock sample of galaxies. The comparison between the ...
Determining X-Ray Source Intensity and Confidence Bounds in Crowded Fields

Primini, F. A.; Kashyap, V. L.

We present a rigorous description of the general problem of aperture photometry in high-energy astrophysics photon-count images, in which the statistical noise model is Poisson, not Gaussian. We compute the full posterior probability density functio ...
EXONEST: Bayesian Model Selection Applied to the Detection and Characterization of Exoplanets via Photometric Variations

Placek, Ben; Knuth, Kevin H.; Angerhausen, Daniel

EXONEST is an algorithm dedicated to detecting and characterizing the photometric signatures of exoplanets, which include reflection and thermal emission, Doppler boosting, and ellipsoidal variations. Using Bayesian inference, we can test between co ...
Optimized Blind Gamma-Ray Pulsar Searches at Fixed Computing Budget

Pletsch, Holger J.; Clark, Colin J.

The sensitivity of blind gamma-ray pulsar searches in multiple years worth of photon data, as from the Fermi LAT, is primarily limited by the finite computational resources available. Addressing this "needle in a haystack" problem, here we present m ...
Exoplanet Population Inference and the Abundance of Earth Analogs from Noisy, Incomplete Catalogs

Foreman-Mackey, Daniel; Hogg, David W.; Morton, Timothy D.

No true extrasolar Earth analog is known. Hundreds of planets have been found around Sun-like stars that are either Earth-sized but on shorter periods, or else on year-long orbits but somewhat larger. Under strong assumptions, exoplanet catalogs hav ...
PRISM: Recovery of the primordial spectrum from Planck data

Lanusse, F.; Paykari, P.; Starck, J.-L.; Sureau, F.; Bobin, J.; Rassat, A.

Aims: The primordial power spectrum describes the initial perturbations that seeded the large-scale structure we observe today. It provides an indirect probe of inflation or other structure-formation mechanisms. In this Letter, we recover the primor ...
Into the third dimension: stochastic measurements of Stokes parameters within the Poincaré sphere

Quinn, Jason L.

Inspired by recent use of polarimetry to study the Cosmic Microwave Background and extragalatic supernovae, a foray into the statistical properties of Stokes parameters expressed in spherical coordinates is began, allowing circular polarization and ...
DIAMONDS: A new Bayesian nested sampling tool. Application to peak bagging of solar-like oscillations

Corsaro, E.; De Ridder, J.

Context. Thanks to the advent of the space-based missions CoRoT and NASA's Kepler, the asteroseismology of solar-like oscillations is now at the base of our understanding about stellar physics. The Kepler spacecraft, especially, is releasing excelle ...
A Fully Bayesian Method for Jointly Fitting Instrumental Calibration and X-Ray Spectral Models

Xu, Jin; van Dyk, David A.; Kashyap, Vinay L.; Siemiginowska, Aneta; Connors, Alanna; Drake, Jeremy; Meng, Xiao-Li; Ratzlaff, Pete; Yu, Yaming

Owing to a lack of robust principled methods, systematic instrumental uncertainties have generally been ignored in astrophysical data analysis despite wide recognition of the importance of including them. Ignoring calibration uncertainty can cause b ...
Understanding the Formation and Evolution of Interstellar Ices: A Bayesian Approach

Makrymallis, Antonios; Viti, Serena

Understanding the physical conditions of dark molecular clouds and star-forming regions is an inverse problem subject to complicated chemistry that varies nonlinearly with both time and the physical environment. In this paper, we apply a Bayesian ap ...
Erasing the Variable: Empirical Foreground Discovery for Global 21 cm Spectrum Experiments

Switzer, Eric R.; Liu, Adrian