January – June 2011

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Improving Sensitivity to Weak Pulsations with Photon Probability Weighting
Kerr, M.

All γ-ray telescopes suffer from source confusion due to their inability to focus incident high-energy radiation, and the resulting background contamination can obscure the periodic emission from faint pulsars. In the context of the Fermi Large Are …

Think Outside the Color Box: Probabilistic Target Selection and the SDSS-XDQSO Quasar Targeting Catalog
Bovy, Jo; Hennawi, Joseph F.; Hogg, David W.; Myers, Adam D.; Kirkpatrick, Jessica A.; Schlegel, David J.; Ross, Nicholas P.; Sheldon, Erin S.; McGreer, Ian D.; Schneider, Donald P.; Weaver, Benjamin A.

We present the SDSS-XDQSO quasar targeting catalog for efficient flux-based quasar target selection down to the faint limit of the Sloan Digital Sky Survey (SDSS) catalog, even at medium redshifts (2.5 <~ z <~ 3) where the stellar contamination is s …

Three-point Correlation Functions of SDSS Galaxies: Luminosity and Color Dependence in Redshift and Projected Space
McBride, Cameron K.; Connolly, Andrew J.; Gardner, Jeffrey P.; Scranton, Ryan; Newman, Jeffrey A.; Scoccimarro, Román; Zehavi, Idit; Schneider, Donald P.

The three-point correlation function (3PCF) provides an important view into the clustering of galaxies that is not available to its lower order cousin, the two-point correlation function (2PCF). Higher order statistics, such as the 3PCF, are necessa …

Interactive visualization of the largest radioastronomy cubes
Hassan, A. H.; Fluke, C. J.; Barnes, D. G.

3D visualization is an important data analysis and knowledge discovery tool, however, interactive visualization of large 3D astronomical datasets poses a challenge for many existing data visualization packages. We present a solution to interactively …

On the Estimation of Confidence Intervals for Binomial Population Proportions in Astronomy: The Simplicity and Superiority of the Bayesian Approach
Cameron, Ewan

I present a critical review of techniques for estimating confidence intervals on binomial population proportions inferred from success counts in small to intermediate samples. Population proportions arise frequently as quantities of interest in astr …

On statistical uncertainty in nested sampling
Keeton, Charles R.

Nested sampling has emerged as a valuable tool for Bayesian analysis, in particular for determining the Bayesian evidence. The method is based on a specific type of random sampling of the likelihood function and prior volume of the parameter space. …

Application of XFASTER power spectrum and likelihood estimator to Planck
Rocha, G.; Contaldi, C. R.; Bond, J. R.; Górski, K. M.

We develop the XFASTER cosmic microwave background (CMB) temperature and polarization anisotropy power spectrum and likelihood technique for the Planck CMB satellite mission. We give an overview of this estimator and its current implementation, and …

The power of Bayesian evidence in astronomy
Jenkins, C. R.; Peacock, J. A.

We discuss the use of the Bayesian evidence ratio, or Bayes factor, for model selection in astronomy. We treat the evidence ratio as a statistic and investigate its distribution over an ensemble of experiments, considering both simple analytical exa …

Introducing Mexican Needlets for CMB Analysis: Issues for Practical Applications and Comparison with Standard Needlets
Scodeller, S.; Rudjord, Ø.; Hansen, F. K.; Marinucci, D.; Geller, D.; Mayeli, A.

Over the last few years, needlets have emerged as a useful tool for the analysis of cosmic microwave background (CMB) data. Our aim in this paper is first to introduce into the CMB literature a different form of needlets, known as Mexican needlets, …

Interference Detection in Gaussian Noise
Baddi, Raju

Interference detection in Gaussian noise is proposed. It can be applied for easy detection and editing of interference lines in radio spectral line observations. One does not need to know the position of occurrence or keep track of interference in t …

An investigation into the Multiple Optimised Parameter Estimation and Data compression algorithm
Graff, Philip; Hobson, Michael P.; Lasenby, Anthony

We investigate the use of the Multiple Optimised Parameter Estimation and Data compression (MOPED) algorithm for data compression and faster evaluation of likelihood functions. Since MOPED only guarantees maintaining the Fisher matrix of the likelih …

A Naive Bayes Source Classifier for X-ray Sources
Broos, Patrick S.; Getman, Konstantin V.; Povich, Matthew S.; Townsley, Leisa K.; Feigelson, Eric D.; Garmire, Gordon P.

The Chandra Carina Complex Project (CCCP) provides a sensitive X-ray survey of a nearby starburst region over >1 deg2 in extent. Thousands of faint X-ray sources are found, many concentrated into rich young stellar clusters. However, significant con …

Density Estimation for Projected Exoplanet Quantities
Brown, Robert A.

Exoplanet searches using radial velocity (RV) and microlensing (ML) produce samples of “projected” mass and orbital radius, respectively. We present a new method for estimating the probability density distribution (density) of the unprojected quanti …

On Machine-learned Classification of Variable Stars with Sparse and Noisy Time-series Data
Richards, Joseph W.; Starr, Dan L.; Butler, Nathaniel R.; Bloom, Joshua S.; Brewer, John M.; Crellin-Quick, Arien; Higgins, Justin; Kennedy, Rachel; Rischard, Maxime

With the coming data deluge from synoptic surveys, there is a need for frameworks that can quickly and automatically produce calibrated classification probabilities for newly observed variables based on small numbers of time-series measurements. In …

Improving Sensitivity to Weak Pulsations with Photon Probability Weighting
Kerr, M.

All γ-ray telescopes suffer from source confusion due to their inability to focus incident high-energy radiation, and the resulting background contamination can obscure the periodic emission from faint pulsars. In the context of the Fermi Large Are …

Accounting for Calibration Uncertainties in X-ray Analysis: Effective Areas in Spectral Fitting
Lee, Hyunsook; Kashyap, Vinay L.; van Dyk, David A.; Connors, Alanna; Drake, Jeremy J.; Izem, Rima; Meng, Xiao-Li; Min, Shandong; Park, Taeyoung; Ratzlaff, Pete; Siemiginowska, Aneta; Zezas, Andreas

While considerable advance has been made to account for statistical uncertainties in astronomical analyses, systematic instrumental uncertainties have been generally ignored. This can be crucial to a proper interpretation of analysis results because …

Bayesian Inference of Solar and Stellar Magnetic Fields in the Weak-field Approximation
Asensio Ramos, A.

The weak-field approximation is one of the simplest models that allows us to relate the observed polarization induced by the Zeeman effect with the magnetic field vector present on the plasma of interest. It is usually applied for diagnosing magneti …

Detection of new point sources in WMAP cosmic microwave background maps at high Galactic latitude. A new technique to extract point sources from CMB maps
Ramos, E. P. R. G.; Vio, R.; Andreani, P.

In experimental microwave maps, point sources can strongly affect the estimate of the power spectrum and/or the test of Gaussianity of the cosmic microwave background (CMB) component. As a consequence, their removal from the sky maps represents a cr …

Improving Interferometric Null Depth Measurements using Statistical Distributions: Theory and First Results with the Palomar Fiber Nuller
Hanot, C.; Mennesson, B.; Martin, S.; Liewer, K.; Loya, F.; Mawet, D.; Riaud, P.; Absil, O.; Serabyn, E.

A new “self-calibrated” statistical analysis method has been developed for the reduction of nulling interferometry data. The idea is to use the statistical distributions of the fluctuating null depth and beam intensities to retrieve the astrophysica …

Bayesian peak-bagging of solar-like oscillators using MCMC: a comprehensive guide
Handberg, R.; Campante, T. L.

Context. Asteroseismology has entered a new era with the advent of the NASA Kepler mission. Long and continuous photometric observations of unprecedented quality are now available which have stimulated the development of a number of suites of innova …