Karl G. Jansky VLA Tutorials

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Introduction

The Karl G. Jansky Very Large Array (VLA) Tutorials are meant to guide the observer through some common types of data analysis, using example datasets, and including explanations of the individual steps. These analyses will be broadly applicable to many VLA data sets.

If you are new to CASA, you may start with

Getting Started in CASA


VLA Data Reduction Tutorials

Carbon Star IRC+10216: high frequency (36GHz), spectral line data reduction

  • This tutorial requires to download a dataset 1.1GB in size

Calibrate and make image cubes of the line emission from this asymptotic giant branch star. This is a high-frequency VLA dataset. Includes:

  • Inspecting data; basic flagging & calibration
  • Subtracting continuum emission
  • Imaging the spectral lines
  • Imaging the continuum
  • Image analysis
  • Self-calibration

Supernova Remnant 3C391: 6cm Polarimetry and Continuum Imaging, Mosaicking

  • This tutorial requires to download a dataset 3.1GB in size

Calibrate VLA full polarization data, image a mosaic of the region in full Stokes and create a spectral index map. Includes:

  • Inspecting data; basic flagging
  • Calibration
  • Image Analysis and Manipulation
  • Polarization Imaging
  • Spectral Index imaging
  • Self-calibration

P-band continuum imaging data reduction tutorial

  • This tutorial requires to download a dataset 21GB in size

This low frequency VLA tutorial for the observation of radio galaxy 3C 129 focuses on low frequency wide-fractional-bandwidth data in the sub GHz regime and demonstrates multi-frequency synthesis imaging with w-projection. This includes:

  • Basic flagging and evaluation
  • Automatic RFI Excision
  • Ionospheric Calibration
  • Self - Calibration
  • Widefield imaging

VLA Topical Guides

Flagging VLA Data in CASA

  • This tutorial requires to download a dataset 4.9GB in size

This tutorial describes different flagging techniques, including: Calibrate and make image cubes of the line emission from this asymptotic giant branch star. This is a high-frequency VLA dataset. Includes:

  • Identifying Problematic Antennas from the Operator Logs
  • Online Flags (shadowing, zeroes, quacking, flagmanager, Hanning smoothing)
  • Automatic RFI excision (TFCrop, RFlag)
  • Interactive Flagging
  • Flagging Summary & Report


Imaging VLA Data in CASA

  • This tutorial requires to download a dataset 1.2GB in size

The Imaging topical guide shows annotated examples of different imaging techniques that are applicable to different science applications. This tutorial includes:

  • An Introduction to the CLEAN algorithm, data and imaging weights, primary and synthesized beams
  • Clean Output Images
  • Dirty Image, Regular CLEAN & RMS Noise, CLEAN with different Weights
  • Multi-Scale CLEAN
  • Multi-Scale, Wide-Field CLEAN (w-projection)
  • Multi-Scale, Multi-Term Frequency Synthesis
  • Multi-Scale, Multi-Term Frequency, Widefield CLEAN
  • Imaging Outlier Fields
  • Primary Beam Correction
  • Imaging Spectral Cubes, Beam per Plane
  • Image Header, Image Conversion


Correcting for a Spectral Index in Bandpass Calibration

This tutorial explains how to obtain a bandpass solution when the bandpass calibrator is a source with an unknown spectral index. This is typically encountered at high frequency observations, where the standard VLA flux density calibrators are too weak for high signal-to-noise bandpass solutions.



VLA CASA Pipeline Guide

The VLA CASA Pipeline Guide provides an example of a VLA CASA pipeline run. The guide explains the pipeline requirements, pipeline execution options, and pipeline output products. The bulk of the tutorial consists of a detailed walk through the weblog and provides interpretations of the plots and tables. The guide also provides instructions on how to run spectral line and polarization data sets and explains how to edit the scan intents if required.


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