Skynet Algorithm for Single-Dish Radio Mapping I: Contaminant-Cleaning, Mapping, and Photometering Small-Scale Structures

Abstract

We present a single-dish mapping algorithm with a number of advantages over traditional techniques. (1) Our algorithm makes use of weighted modeling, instead of weighted averaging, to interpolate between signal measurements. This smooths the data, but without blurring the data beyond instrumental resolution. Techniques that rely on weighted averaging blur point sources sometimes as much as 40%. (2) Our algorithm makes use of local, instead of global, modeling to separate astronomical signal from instrumental and/or environmental signal drift along the telescope's scans. Other techniques, such as basket weaving, model this drift with simple functional forms (linear, quadratic, etc.) across the entirety of scans, limiting their ability to remove such contaminants. (3) Our algorithm makes use of a similar, local modeling technique to separate astronomical signal from radio-frequency interference (RFI), even if only continuum data are available. (4) Unlike other techniques, our algorithm does not require data to be collected on a rectangular grid or regridded before processing. (5) Data from any number of observations, overlapping or not, may be appended and processed together. (6) Any pixel density may be selected for the final image. We present our algorithm, and evaluate it using both simulated and real data. We are integrating it into the image-processing library of the Skynet Robotic Telescope Network, which includes optical telescopes spanning four continents, and now also Green Bank Observatory's 20-meter diameter radio telescope in West Virginia. Skynet serves hundreds of professional users, and additionally tens of thousands of students, of all ages. Default data products are generated on the fly, but will soon be customizable after the fact.

arXiv comment50 pages, 54 figures, 4 tables, accepted for publication in ApJS

References in corpus (86)

• Multi-messenger Observations of a Binary Neutron Star Merger
• The discovery of the electromagnetic counterpart of GW170817: kilonova AT 2017gfo/DLT17ck
• Type Iax Supernovae: A New Class of Stellar Explosion
• A ring system detected around the Centaur (10199) Chariklo
• Interacting Supernovae and Supernova Impostors. SN 2009ip, is this the end?
• Formation of asteroid pairs by rotational fission
• Afterglow Observations of Fermi-LAT Gamma-Ray Bursts and the Emerging Class of Hyper-Energetic Events
• Primary black hole spin in OJ287 as determined by the General Relativity centenary flare
• SN 2009jf: a slow-evolving stripped-envelope core-collapse supernova
• The On The Fly Imaging Technique
• SN 2009ip á la PESSTO: No evidence for core-collapse yet
• The Highly Energetic Expansion of SN2010bh Associated with GRB 100316D
• The early detection and follow-up of the highly obscured Type II supernova 2016ija/DLT16am
• Discovery and identification of the very high redshift afterglow of GRB 050904
• SN 2009bb: a Peculiar Broad-Lined Type Ic Supernova
• Large Impacts around a Solar Analog Star in the Era of Terrestrial Planet Formation
• Effective Temperatures of Cataclysmic Variable White Dwarfs as a Probe of their Evolution
• Multi-Wavelength Observations of Supernova 2011ei: Time-Dependent Classification of Type IIb and Ib Supernovae and Implications for their Progenitors
• The Type IIP Supernova 2012aw in M95: hydrodynamical modelling of the photospheric phase from accurate spectrophotometric monitoring
• A tale of two GRB-SNe at a common redshift of z = 0.54
• SN 2009N: Linking normal and subluminous type II-P SNe
• The warm, the excited, and the molecular gas: GRB 121024A shining through its star-forming galaxy
• Multiple Asteroid Systems: Dimensions and Thermal Properties from Spitzer Space Telescope and Ground-Based Observations
• Stochastic modeling of multiwavelength variability of the classical BL Lac object OJ 287 on timescales ranging from decades to hours
• Optical and Near-IR Observations of the Faint and Fast 2008ha-like Supernova 2010ae
• Living with a Red Dwarf: Rotation and X-ray and Ultraviolet Properties of the Halo Population Kapteyn's Star
• The progenitor and early evolution of the Type IIb SN 2016gkg
• Planetary Collisions outside the Solar System: Time Domain Characterization of Extreme Debris Disks
• SN 2009ib: A Type II-P Supernova with an Unusually Long Plateau
• PESSTO monitoring of SN 2012hn: further heterogeneity among faint type I supernovae
• Pluto's atmosphere from stellar occultations in 2012 and 2013
• GRB 081007 and GRB 090424: the surrounding medium, outflows and supernovae
• Supernova 2010as: the Lowest-Velocity Member of a Family of Flat-Velocity Type IIb Supernovae
• SN 2012ec: mass of the progenitor from PESSTO follow-up of the photospheric phase
• On the Progenitor and Supernova of the SN 2002cx-like Supernova 2008ge
• Supernova 2012ec: Identification of the progenitor and early monitoring with PESSTO
• SN 2016coi/ASASSN-16fp: An example of residual helium in a type Ic supernova?
• Optical and X-Ray Observations of GRB 060526: A Complex Afterglow Consistent with An Achromatic Jet Break
• The First Maximum-Light Ultraviolet through Near-Infrared Spectrum of a Type Ia Supernova
• KELT-10b: The First Transiting Exoplanet from the KELT-South Survey -- A Hot Sub-Jupiter Transiting a V = 10.7 Early G-Star
• Transit timing variation and transmission spectroscopy analyses of the hot Neptune GJ3470b
• On type IIn/Ia-CSM supernovae as exemplified by SN 2012ca
• 1FGL J1417.7-4407: A likely gamma-ray bright binary with a massive neutron star and a giant secondary
• Toward Understanding the B[e] Phenomenon. VII. AS 386, a single-lined binary with a candidate black hole component
• Evidence for Dust Destruction from the Early-time Colour Change of GRB 120119A
• GRB 120711A: an intense INTEGRAL burst with long-lasting soft gamma-ray emission and a powerful optical flash
• An empirical limit on the kilonova rate from the DLT40 one day cadence Supernova Survey
• Type II supernovae in low luminosity host galaxies
• EC 10246-2707: a new eclipsing sdB + M dwarf binary
• Orbital and physical parameters of eclipsing binaries from the ASAS catalogue - VIII. The totally-eclipsing double-giant system HD 187669
• New insights on the binary asteroid 121 Hermione
• Mass and period limits on the ringed companion transiting the young star J1407
• The Rapidly Flaring Afterglow of the Very Bright and Energetic GRB 070125
• Eclipses During the 2010 Eruption of the Recurrent Nova U Scorpii
• Orbital and physical parameters of eclipsing binaries from the ASAS catalogue - IV. A 0.61 + 0.45 M_sun binary in a multiple system
• The central engine of GRB 130831A and the energy breakdown of a relativistic explosion
• PROMPT Observations of the Early-Time Optical Afterglow of GRB 060607A
• Discovery of two new Galactic candidate luminous blue variables with WISE
• IGR J19552+0044: A new asynchronous short period polar: "Filling the gap between intermediate and ordinary polars"
• SN 2012ca: a stripped envelope core-collapse SN interacting with dense circumstellar medium
• The Fading of Supernova Remnant Cassiopeia A from 38 MHz to 16.5 GHz from 1949 to 1999 with New Observations at 1405 MHz
• Photometry and spectroscopy of the new sdBV CS 1246
• 2FGL J0846.0+2820: A new neutron star binary with a giant secondary and variable $\gamma$-ray emission
• A Bright Short Period M-M Eclipsing Binary from the KELT Survey: Magnetic Activity and the Mass-Radius Relationship for M-dwarfs
• The remarkable outburst of the highly evolved post-period-minimum dwarf nova SSS J122221.7-311525
• Orbital and physical parameters of eclipsing binaries from the ASAS catalogue -- III. Two new low-mass systems with rapidly evolving spots
• A method of immediate detection of objects with a near-zero apparent motion in series of CCD-frames
• Robust Chauvenet Outlier Rejection
• The fading of Cassiopeia A, and improved models for the absolute spectrum of primary radio calibration sources
• Radio and optical intra-day variability observations of five blazars
• Fortnightly Fluctuations in the O-C Diagram of CS 1246
• Pulsational Mapping of Calcium Across the Surface of a White Dwarf
• Supernova 2010ev: A reddened high velocity gradient type Ia supernova
• A search for rapidly pulsating hot subdwarf stars in the GALEX survey
• Towards Understanding The B[e] Phenomenon: VI. Nature and Spectral Variations of HD 85567
• A Multi-Year Search For Transits Of Proxima Centauri. I: Light Curves Corresponding To Published Ephemerides
• Optical photometry and spectroscopy of the 1987A-like supernova 2009mw
• Efficient least-squares basket-weaving
• Confirmation of the Luminous Blue Variable status of MWC 930
• The Magnetic Cataclysmic Variable LSQ1725-64
• Ultraviolet Study of the Active Interacting Binary Star R Arae using Archival IUE Data
• Colour variations in the GRB 120327A afterglow
• Long orbital period pre-polars containing an early K-type donor stars. Bottleneck accretion mechanism in action
• Photometric Observations of Three High Mass X-Ray Binaries and a Search for Variations Induced by Orbital Motion
• GRB 141221A: gone is the wind
• Variable Stars in Metal-Rich Globular Clusters. IV. Long Period Variables in NGC 6496

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