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The giant lobes of Centaurus A observed at 118 MHz with the Murchison Widefield Array
- Source :
- arXiv
- Publication Year :
- 2013
- Publisher :
- arXiv, 2013.
-
Abstract
- We present new wide-field observations of Centaurus A (Cen A) and the surrounding region at 118 MHz with the Murchison Widefield Array (MWA) 32-tile prototype, with which we investigate the spectral-index distribution of Cen A's giant radio lobes. We compare our images to 1.4 GHz maps of Cen A and compute spectral indices using temperature–temperature plots and spectral tomography. We find that the morphologies at 118 MHz and 1.4 GHz match very closely apart from an extra peak in the southern lobe at 118 MHz, which provides tentative evidence for the existence of a southern counterpart to the northern middle lobe of Cen A. Our spatially averaged spectral indices for both the northern and southern lobes are consistent with previous analyses, however we find significant spatial variation of the spectra across the extent of each lobe. Both the spectral-index distribution and the morphology at low radio frequencies support a scenario of multiple outbursts of activity from the central engine. Our results are consistent with inverse-Compton modelling of radio and gamma-ray data that support a value for the lobe age of between 10 and 80 Myr.<br />National Science Foundation (U.S.) (Grant AST-0457585)<br />National Science Foundation (U.S.) (Grant PHY-0835713)<br />National Science Foundation (U.S.) (Grant CAREER-0847753)<br />National Science Foundation (U.S.) (Grant AST-0908884)<br />United States. Air Force Office of Scientific Research (Grant FA9550-0510247)<br />Smithsonian Astrophysical Observatory<br />MIT School of Science
- Subjects :
- Active galactic nucleus
Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Radio galaxy
Astrophysics::High Energy Astrophysical Phenomena
Centaurus A
FOS: Physical sciences
Murchison Widefield Array
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
01 natural sciences
X-shaped radio galaxy
0103 physical sciences
medicine
Astrophysics::Solar and Stellar Astrophysics
010306 general physics
010303 astronomy & astrophysics
Reionization
Astrophysics::Galaxy Astrophysics
Physics
Astronomy
Astronomy and Astrophysics
Galaxy
Lobe
medicine.anatomical_structure
Space and Planetary Science
Astrophysics - Cosmology and Nongalactic Astrophysics
Subjects
Details
- ISSN :
- 95500510
- Database :
- OpenAIRE
- Journal :
- arXiv
- Accession number :
- edsair.doi.dedup.....3c8f4162a9d6effdf81fe4e703ee7cdb
- Full Text :
- https://doi.org/10.48550/arxiv.1309.0916