skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: EXPANDED VERY LARGE ARRAY OBSERVATIONS OF GALACTIC SUPERNOVA REMNANTS: WIDE-FIELD CONTINUUM AND SPECTRAL-INDEX IMAGING

Abstract

The radio continuum emission from the Galaxy has a rich mix of thermal and non-thermal emission. This very richness makes its interpretation challenging since the low radio opacity means that a radio image represents the sum of all emission regions along the line of sight. These challenges make the existing narrowband radio surveys of the Galactic plane difficult to interpret: e.g., a small region of emission might be a supernova remnant (SNR) or an H II region, or a complex combination of both. Instantaneous wide bandwidth radio observations in combination with the capability for high-resolution spectral-index mapping can be directly used to disentangle these effects. Here we demonstrate simultaneous continuum and spectral-index imaging capability at the full continuum sensitivity and resolution using newly developed wide-band wide-field imaging algorithms. Observations were conducted in the L and C bands with a total bandwidth of 1 and 2 GHz, respectively. We present preliminary results in the form of a full-field continuum image covering the wide-band sensitivity pattern of the EVLA centered on a large but poorly studied SNR (G55.7 + 3.4) and relatively narrower field continuum and spectral-index maps of three fields containing SNR and diffused thermal emission. We demonstrate that spatially resolvedmore » spectral-index maps differentiate regions with emission of different physical origins (spectral-index variation across composite SNRs and separation of thermal and non-thermal emission), superimposed along the line of sight. The wide-field image centered on the SNR G55.7+3.4 also demonstrates the excellent wide-field wide-band imaging capability of the EVLA.« less

Authors:
; ;  [1];  [2]
  1. National Radio Astronomy Observatory, Socorro, NM 87801 (United States)
  2. Astrophysics Group, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom)
Publication Date:
OSTI Identifier:
21565454
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 739; Journal Issue: 1; Other Information: DOI: 10.1088/2041-8205/739/1/L20; Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALGORITHMS; EMISSION; GALAXIES; IMAGES; MAPPING; RADIOWAVE RADIATION; SUPERNOVA REMNANTS; COSMIC RADIO SOURCES; ELECTROMAGNETIC RADIATION; MATHEMATICAL LOGIC; RADIATIONS

Citation Formats

Bhatnagar, S., Rau, U., Rupen, M. P., and Green, D. A., E-mail: sbhatnag@nrao.edu, E-mail: rurvashi@nrao.edu, E-mail: mrupen@nrao.edu, E-mail: dag9@cam.ac.uk. EXPANDED VERY LARGE ARRAY OBSERVATIONS OF GALACTIC SUPERNOVA REMNANTS: WIDE-FIELD CONTINUUM AND SPECTRAL-INDEX IMAGING. United States: N. p., 2011. Web. doi:10.1088/2041-8205/739/1/L20.
Bhatnagar, S., Rau, U., Rupen, M. P., & Green, D. A., E-mail: sbhatnag@nrao.edu, E-mail: rurvashi@nrao.edu, E-mail: mrupen@nrao.edu, E-mail: dag9@cam.ac.uk. EXPANDED VERY LARGE ARRAY OBSERVATIONS OF GALACTIC SUPERNOVA REMNANTS: WIDE-FIELD CONTINUUM AND SPECTRAL-INDEX IMAGING. United States. doi:10.1088/2041-8205/739/1/L20.
Bhatnagar, S., Rau, U., Rupen, M. P., and Green, D. A., E-mail: sbhatnag@nrao.edu, E-mail: rurvashi@nrao.edu, E-mail: mrupen@nrao.edu, E-mail: dag9@cam.ac.uk. Tue . "EXPANDED VERY LARGE ARRAY OBSERVATIONS OF GALACTIC SUPERNOVA REMNANTS: WIDE-FIELD CONTINUUM AND SPECTRAL-INDEX IMAGING". United States. doi:10.1088/2041-8205/739/1/L20.
@article{osti_21565454,
title = {EXPANDED VERY LARGE ARRAY OBSERVATIONS OF GALACTIC SUPERNOVA REMNANTS: WIDE-FIELD CONTINUUM AND SPECTRAL-INDEX IMAGING},
author = {Bhatnagar, S. and Rau, U. and Rupen, M. P. and Green, D. A., E-mail: sbhatnag@nrao.edu, E-mail: rurvashi@nrao.edu, E-mail: mrupen@nrao.edu, E-mail: dag9@cam.ac.uk},
abstractNote = {The radio continuum emission from the Galaxy has a rich mix of thermal and non-thermal emission. This very richness makes its interpretation challenging since the low radio opacity means that a radio image represents the sum of all emission regions along the line of sight. These challenges make the existing narrowband radio surveys of the Galactic plane difficult to interpret: e.g., a small region of emission might be a supernova remnant (SNR) or an H II region, or a complex combination of both. Instantaneous wide bandwidth radio observations in combination with the capability for high-resolution spectral-index mapping can be directly used to disentangle these effects. Here we demonstrate simultaneous continuum and spectral-index imaging capability at the full continuum sensitivity and resolution using newly developed wide-band wide-field imaging algorithms. Observations were conducted in the L and C bands with a total bandwidth of 1 and 2 GHz, respectively. We present preliminary results in the form of a full-field continuum image covering the wide-band sensitivity pattern of the EVLA centered on a large but poorly studied SNR (G55.7 + 3.4) and relatively narrower field continuum and spectral-index maps of three fields containing SNR and diffused thermal emission. We demonstrate that spatially resolved spectral-index maps differentiate regions with emission of different physical origins (spectral-index variation across composite SNRs and separation of thermal and non-thermal emission), superimposed along the line of sight. The wide-field image centered on the SNR G55.7+3.4 also demonstrates the excellent wide-field wide-band imaging capability of the EVLA.},
doi = {10.1088/2041-8205/739/1/L20},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 739,
place = {United States},
year = {2011},
month = {9}
}