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Title: ATLBS extended source sample : The evolution in radio source morphology with flux density
Authors: Saripalli, Lakshmi
Subrahmanyan, Ravi
Thorat, K.
Ekers, R.D.
Hunstead, R.W.
Johnston, H.M.
Sadler, E.M.
Keywords: Galaxies: active
Radio continuum
Issue Date: 15-Mar-2012
Publisher: IOP Publishing for the American Astronomical Society
Citation: Astrophysical Journal Supplement Series, 2012, Vol. 199, p27
Abstract: Based on the Australia Telescope Low Brightness Survey (ATLBS) we present a sample of extended radio sources and derive morphological properties of faint radio sources. One hundred nineteen radio galaxies form the ATLBS Extended Source Sample (ATLBS-ESS) consisting of all sources exceeding 30 in extent and integrated flux densities exceeding 1 mJy. We give structural details along with information on galaxy identifications and source classifications. The ATLBS-ESS, unlike samples with higher flux-density limits, has almost equal fractions of FR-I and FR-II radio galaxies, with a large fraction of the FR-I population exhibiting 3C31-type structures. Significant asymmetry in lobe extents appears to be a common occurrence in the ATLBS-ESS FR-I sources compared with FR-II sources. We present a sample of 22 FR-Is at z > 0.5 with good structural information. The detection of several giant radio sources, with size exceeding 0.7 Mpc, at z > 1 suggests that giant radio sources are not less common at high redshifts. The ESS also includes a sample of 28 restarted radio galaxies. The relative abundance of dying and restarting sources is indicative of a model where radio sources undergo episodic activity in which an active phase is followed by a brief dying phase that terminates with restarting of the central activity; in any massive elliptical a few such activity cycles wherein adjacent events blend may constitute the lifetime of a radio source and such bursts of blended activity cycles may be repeated over the age of the host. The ATLBS-ESS includes a 2 Mpc giant radio galaxy with the lowest surface brightness lobes known to date.
Description: Restricted Access. An open-access version is available at (one of the alternative locations)
ISSN: 1538-4365-(online)
0067-0049 (Print)
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Copyright: 2012 The American Astronomical Society
Appears in Collections:Research Papers (A&A)

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