Radio Interferometry Tutorial

Sylvia Adscheid, Dr. Beth Jones, Dr. Benjamin Magnelli, Dr. Lydia Moser-Fischer, Dr. Stefanie Mühle
 
 

Course Material


Important note: The following lecture material is only intended for the personal use of the registered participants and may therefore be encrypted with a password. By accessing the material, whether encrypted or not, you agree that you won't share the material or the password with anyone not registered for this course and that you won't make the files or the password available online.

Material for the lecture part

Introductory Videos on ALMA, Radio Interferometry and more (Cycle 9 Proposal Preparation Support)



Introduction to Radio Interferometry, part 0

Introduction to Radio Interferometry, part 1

Introduction to Radio Interferometry, part 2

Introduction to Radio Interferometry, part 3

Introduction to Radio Interferometry, part 4

Introduction to Radio Interferometry, part 5

Introduction to Radio Interferometry, part 6

Introduction to Radio Interferometry (videos)

Introduction to CASA

First steps in CASA



Data reduction, part 1:

Calibration Basics, part 1: Visibility Corruption

Calibration Basics, part 2: Cross Calibration

Calibration Basics, part 3: Calibration Flow

Calibration Basics (videos)

Calibration 1: import, listobs (slides)

Calibration 1: T_sys, WVR (slides)

Calibration 1: T_sys, WVR - Checks (slides)

Calibration 1 (videos)



Data reduction, part 2:

Calibration 2: bandpass (slides)

Calibration 2: flux (slides)

Calibration 2 (videos)





Material for the hands-on part

Preparatory tutorial (optional): For those new to Linux and command-line computing, there are a number of free introductory tutorials available online. A rather concise one that covers the most important basics in the first 5 chapters (~40 minutes to read) can be found here.

my_first_script.py

script for calibration, week 1 --- solutions

script for calibration, week 2

Data sets

The lecture data set (~5.7 GB) is the data set that will be used during the hands-on work in the tutorials. Solutions in form of a template script will be posted at regular intervals.

The homework data set (~5.8 GB) is a data set that all participants can use for practicing their data reduction skills.

The participants with an account on the node compute server will find a copy of the data sets and a suite of analysis scripts in their project accounts. All other participants are cordially invited to download the data and the analysis scripts to their own machines from this link. Please check that the download has ended successfully by comparing the output of "md5sum " with the checksum provided in the readme file. The data and scripts are available in form of tarballs that need to be unpacked by typing "tar -xvf filename.tar" prior to being used in CASA.


Literature

Synthesis Imaging in Radio Astronomy II, ASP Conference Series, V. 180, 1998, Editors: Taylor, Carilli, Perley

Interferometry and Synthesis in Radio Astronomy (Wiley 2001), by Thompson, Moran, Swenson

CASA Guides

astro841: Radio Astronomy, graduate-level course at Bonn university

Essential Radio Astronomy (a basic introduction to radio astronomy in general, as an alternative to astro841)

ALMA Cycle 11 Proposer's Guide (example of relevant technical parameters and procedures)

ALMA Cycle 11 Technical Handbook (detailed technical information specific to ALMA)


Software

Throughout this course, we will use the Common Astronomy Software Applications package (CASA) for the reduction and analysis of our interferometric data. The main source of information related to CASA is the CASA homepage .

In the tutorials, the CASA release 6.2.1 (ALMA Pipeline) will be used. This CASA version is already installed on the compute server.

Participants who want to do the data reduction on their own machine are kindly requested to download and install CASA themselves. Detailed installation instructions can be found in the current Release Information. Please note that there are two ways of installing CASA: The monolithic installation requires downloading a tar-file that already includes the necessary Python environment. Alternatively, the latest CASA version (without pipelines) can also be installed as a modular version with pip-wheels. The version that will be used in the tutorials is CASA 6.2.1 (ALMA pipeline) and is only available as a tar-file.

The official documentation for the latest CASA releases can be found here. Further documentation is available in the form of CASA Guides.