Radio Study of Galactic Supernova Remnants and the Interstellar Medium

A Thesis submitted for the degree of
Doctor of Philosophy
to the
SANJAY BHATNAGAR National Centre for Radio Astrophysics
Tata Institute of Fundamental Research
Pune - 411 007
July 2001

List of Figures
List of Tables
1 Introduction
 1.1 Synchrotron Radiation
 1.2 Galactic Supernova Remnants
 1.3 Effects of the ISM on the observed properties of SNRs
 1.4 Why low frequency?
 1.5 Aperture synthesis at low frequencies
 1.6 Organization of the thesis
2 The Giant Meterwave Radio Telescope
 2.1 Principles of aperture synthesis
 2.2 The Array
 2.3 Signal flow
 2.4 Telescope parameters
 2.5 The GMRT correlator
 2.6 Baseline and fixed delay calibration
3 Data analysis software
 3.1 Introduction
 3.2 The software design
 3.3 Data manipulation libraries
 3.4 The user interface for off-line programs
 3.5 Data analysis and display programs
4 The GMRT Data
 4.1 GMRT Observations
 4.2 Low frequency specific problems
 4.3 Observational procedure
 4.4 Data Analysis
 4.5 Inversion and deconvolution of GMRT data
 4.6 The Images
5 Observations of Supernova Remnants
 5.1 Introduction
 5.2 Candidate SNRs
 5.3 Continuum flux densities of known SNRs
 5.4 Discussion
6 Other objects in the fields
 6.1 Introduction
 6.2 Point sources in the fields
 6.3 Extended sources
 6.4 Extended emission around Ultra Compact HII regions
 6.5 Discussion
7 Measurement of polarization leakage
 7.1 Introduction
 7.2 Motivation
 7.3 Algorithm and simulation
 7.4 Real data
 7.5 Closure phase and the Poincaré sphere
 7.6 Non-uniqueness of solutions
 7.7 Conclusions
8 Conclusions
 8.1 Using the Giant Meterwave Radio Telescope
 8.2 Candidate Galactic SNRs
 8.3 Other sources in the fields
 8.4 Future directions
 8.5 Some thoughts on the role of software for the GMRT
A The user interface for off-line applications
 A.1 The User interface commands
 A.2 Customization
B The xtract macro language
 B.1 The macro language
 B.2 Output filters
 B.3 Internal design
 B.4 Programming with the xtract library
 B.5 Adding new elements to the syntax
C Antenna/baseline naming convention
 C.1 Antenna naming convention
 C.2 Baseline naming convention
D Computation of antenna based complex gains
 D.1 Interpretation of the equation
 D.2 Estimation of the system temperature (Ts)
 D.3 Derivation of gi using real and imaginary parts