6533b85cfe1ef96bd12bcb3c
RESEARCH PRODUCT
Spurious source generation in mapping from noisy phase-self-calibrated data
Ivan Marti-vidalJ. M. Marcaidesubject
media_common.quotation_subjectPhase (waves)FOS: Physical sciencesAstrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICAAstrophysicsNoise (electronics)Calibrationimage processing [Techniques]UNESCO::ASTRONOMÍA Y ASTROFÍSICA::Otras especialidades astronómicasdata analysis [Methods]Spurious relationshipmedia_commonPhysicsArtifact (error)Techniques : interferometric; Methods : data analysis; Techniques : image processingAstrophysics (astro-ph)Astrophysics::Instrumentation and Methods for AstrophysicsAstronomy and AstrophysicsInterferometryDistribution (mathematics)Space and Planetary ScienceSkyinterferometric [Techniques]Algorithm:ASTRONOMÍA Y ASTROFÍSICA::Otras especialidades astronómicas [UNESCO]:ASTRONOMÍA Y ASTROFÍSICA [UNESCO]description
Phase self-calibration (or selfcal) is an algorithm often used in the calibration of interferometric observations in astronomy. Although a powerful tool, this algorithm presents strong limitations when applied to data with a low signal-to-noise ratio. We analyze the artifacts that the phase selfcal algorithm produces when applied to extremely noisy data. We show how the phase selfcal may generate a spurious source in the sky from a distribution of completely random visibilities. This spurious source is indistinguishable from a real one. We numerically and analytically compute the relationship between the maximum spurious flux density generated by selfcal from noise and the particulars of the interferometric observations. Finally, we present two simple tests that can be applied to interferometric data for checking whether a source detection is real or whether the source is an artifact of the phase self-calibration algorithm.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2008-01-08 | Astronomy & Astrophysics |