Skip to content. | Skip to navigation

Personal tools

Navigation

You are here: Home / Recent Papers / July - December 2013

July - December 2013

Region-Based Querying of Solar Data Using Descriptor Signatures

Banda, J.M. ; Chang Liu ; Angryk, R.A.

In this work we present our first results on the ambitious task of providing region-based querying capabilities to our existing Solar Dynamics Observatory (SDO) content-based image-retrieval (CBIR) system. By taking advantage of precomputed image de ...
Calculation and Applications of Bayesian Evidence in Astrophysics and Particle Physics Phenomenology

Feroz, F.

Bayesian inference is usually divided into two categories: parameter estimation and model selection. Parameter estimation is mostly performed using Markov Chain Monte Carlo (MCMC) sampling methods, most often based on the standard Metropolis-Hasting ...
Neural Networks for Astronomical Data Analysis and Bayesian Inference

Graff, P. ; Feroz, F. ; Hobson, M.P. ; Lasenby, A.

We present our generic neural network training algorithm, called Sky Net and the accelerated Bayesian inference algorithm, BAMBI. Sky Net combines multiple techniques already developed individually in the literature to create an efficient and robust ...
Online Classification for Time-Domain Astronomy

Lo, K.K. ; Murphy, T. ; Rebbapragada, U. ; Wagstaff, K.

The advent of synoptic sky surveys has spurred the development of techniques for real-time classification of astronomical sources in order to ensure timely follow-up with appropriate instruments. Previous work has focused on algorithm selection or i ...
On Using SIFT Descriptors for Image Parameter Evaluation

McInerney, P.M. ; Banda, J.M. ; Angryk, R.A.

In this work we present a composite method for image parameter evaluation using Scale-Invariant Feature Transform (SIFT) descriptors and bag of words representation applied to pre-selected image parameters, with potential applications to solar data ...
Automatic Identification of Hexagonal Pattern Artifacts in Radio Astronomical Surveys

Said, D. ; Stil, J. ; Taylor, R. ; Barker, K.

The Radio Astronomical Survey (RAS) is a collection of image cubes that represent specific regions in the sky. They are produced through an automated Data Processing Pipeline. In this process, radio astronomical signals received from a radio telesco ...
Astronomical image denoising using dictionary learning

Beckouche, S.; Starck, J. L.; Fadili, J.

Astronomical images suffer a constant presence of multiple defects that are consequences of the atmospheric conditions and of the intrinsic properties of the acquisition equipment. One of the most frequent defects in astronomical imaging is the pres ...
Darth Fader: Using wavelets to obtain accurate redshifts of spectra at very low signal-to-noise

Machado, D. P.; Leonard, A.; Starck, J.-L.; Abdalla, F. B.; Jouvel, S.

Context. Accurate determination of the redshifts of galaxies comes from the identification of key lines in their spectra. Large sky surveys, and the sheer volume of data they produce, have made it necessary to tackle this identification problem in a ...
Removal of two large-scale cosmic microwave background anomalies after subtraction of the integrated Sachs-Wolfe effect

Rassat, A.; Starck, J.-L.; Dupé, F.-X.

Context. Although there is currently a debate over the significance of the claimed large-scale anomalies in the cosmic microwave background (CMB), their existence is not totally dismissed. In parallel to the debate over their statistical significanc ...
On preferred axes in WMAP cosmic microwave background data after subtraction of the integrated Sachs-Wolfe effect

Rassat, A.; Starck, J.-L.; Dupé, F.-X.

There is currently a debate over the existence of claimed statistical anomalies in the cosmic microwave background (CMB), recently confirmed in Planck data. Recent work has focussed on methods for measuring statistical significance, on masks and on ...
The Gaia astrophysical parameters inference system (Apsis). Pre-launch description

Bailer-Jones, C. A. L.; Andrae, R.; Arcay, B.; Astraatmadja, T.; Bellas-Velidis, I.; Berihuete, A.; Bijaoui, A.; Carrión, C.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; de Laverny, P.; Delchambre, L.; Drazinos, P.; Drimmel, R.; Frémat, Y.; Fustes, D.; García-Torres, M.; Guédé, C.; Heiter, U.; Janotto, A.-M.; Karampelas, A.; Kim, D.-W.; Knude, J.; Kolka, I.; Kontizas, E.; Kontizas, M.; Korn, A. J.; Lanzafame, A. C.; Lebreton, Y.; Lindstrøm, H.; Liu, C.; Livanou, E.; Lobel, A.; Manteiga, M.; Martayan, C.; Ordenovic, Ch.; Pichon, B.; Recio-Blanco, A.; Rocca-Volmerange, B.; Sarro, L. M.; Smith, K.; Sordo, R.; Soubiran, C.; Surdej, J.; Thévenin, F.; Tsalmantza, P.; Vallenari, A.; Zorec, J.

The Gaia satellite will survey the entire celestial sphere down to 20th magnitude, obtaining astrometry, photometry, and low resolution spectrophotometry on one billion astronomical sources, plus radial velocities for over one hundred million stars. ...
Automated data reduction workflows for astronomy. The ESO Reflex environment

Freudling, W.; Romaniello, M.; Bramich, D. M.; Ballester, P.; Forchi, V.; García-Dabló, C. E.; Moehler, S.; Neeser, M. J.

Context. Data from complex modern astronomical instruments often consist of a large number of different science and calibration files, and their reduction requires a variety of software tools. The execution chain of the tools represents a complex wo ...
Photo-Met: A non-parametric method for estimating stellar metallicity from photometric observations

Kerekes, Gy.; Csabai, I.; Dobos, L.; Trencséni, M.

Getting spectra at good signal-to-noise ratios takes orders of magnitudes more time than photometric observations. Building on the technique developed for photometric redshift estimation of galaxies, we develop and demonstrate a non-parametric photo ...
PyWiFeS: a rapid data reduction pipeline for the Wide Field Spectrograph (WiFeS)

Childress, Michael J.; Vogt, Frédéric P. A.; Nielsen, Jon; Sharp, Robert G.

We present PyWiFeS, a new Python-based data reduction pipeline for the Wide Field Spectrograph (WiFeS). PyWiFeS consists of a series of core data processing routines built on standard scientific Python packages commonly used in astronomical applicat ...
Calculating Time Lags from Unevenly Sampled Light Curves

Zoghbi, A.; Reynolds, C.; Cackett, E. M.

Timing techniques are powerful tools to study dynamical astrophysical phenomena. In the X-ray band, they offer the potential of probing accretion physics down to the event horizon. Recent work has used frequency- and energy-dependent time lags as to ...
Automatic Classification of Variable Stars in Catalogs with Missing Data

Pichara, Karim; Protopapas, Pavlos

We present an automatic classification method for astronomical catalogs with missing data. We use Bayesian networks and a probabilistic graphical model that allows us to perform inference to predict missing values given observed data and dependency ...
A Search for Pulsations in Short Gamma-Ray Bursts to Constrain their Progenitors

Dichiara, S.; Guidorzi, C.; Frontera, F.; Amati, L.

We searched for periodic and quasi-periodic signals in the prompt emission of a sample of 44 bright short gamma-ray bursts (GRBs) detected with Fermi/GBM, Swift/BAT, and CGRO/BATSE. The aim was to look for the observational signature of quasi-period ...
The Pan-STARRS1 Small Area Survey 2

Metcalfe, N.; Farrow, D. J.; Cole, S.; Draper, P. W.; Norberg, P.; Burgett, W. S.; Chambers, K. C.; Denneau, L.; Flewelling, H.; Kaiser, N.; Kudritzki, R.; Magnier, E. A.; Morgan, J. S.; Price, P. A.; Sweeney, W.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.

The Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1) survey is acquiring multi-epoch imaging in five bands (gP1, rP1, iP1, zP1, yP1) over the entire sky north of declination -30° (the 3π survey). In 2011 July a test area of abo ...
Exploring the non-linear density field in the Millennium Simulations with tessellations - I. The probability distribution function

Pandey, Biswajit; White, Simon D. M.; Springel, Volker; Angulo, Raul E.

We use the Delaunay Tessellation Field Estimator (DTFE) to study the one-point density distribution functions of the Millennium Simulation (MS) and Millennium-II Simulation (MS-II). The DTFE technique is based directly on the particle positions, wit ...
Spectral ageing in the lobes of FR-II radio galaxies: new methods of analysis for broad-band radio data

Harwood, Jeremy J.; Hardcastle, Martin J.; Croston, Judith H.; Goodger, Joanna L.

The broad-bandwidth capabilities of next generation telescopes such as the Jansky Very Large Array (JVLA) mean that the spectrum of any given source varies significantly within the bandwidth of any given observation. Detailed spectral analysis takin ...