Relics of double radio sources

Dwarakanath, K.S.; Kale, Ruta

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/3815

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DC Field	Value	Language
dc.contributor.author	Dwarakanath, K.S.	-
dc.contributor.author	Kale, Ruta	-
dc.date.accessioned	2009-07-31T10:12:49Z	-
dc.date.available	2009-07-31T10:12:49Z	-
dc.date.issued	2009-06-20	-
dc.identifier.citation	Astrophysical Journal, 2009, Vol. 698, pL163	en
dc.identifier.issn	0004-637X	-
dc.identifier.issn	1538-4357 (online)	-
dc.identifier.uri	http://hdl.handle.net/2289/3815	-
dc.description	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations). Articles older than 2 years are open to all at the journal site (alternative location)	en
dc.description.abstract	We have formed a new sample which consists of extended extragalactic radio sources without obvious active galactic nuclei (AGNs) in them. Most of these sources appear to be dead double radio sources. These sources with steep spectra (α < –1.8; S vprop να) were identified using the 74 (VLSS) and the 1400 MHz (NVSS) surveys and further imaged using the Very Large Array (VLA) and the Giant Meterwave Radio Telescope (GMRT). The radio morphologies of these sources are rather unusual in the sense that no obvious cores and jets are detected in these sources, but two extended lobes are detected in most. The mean redshift of 4 of the 10 sources reported here is ~ 0.2. At a redshift of 0.2, the linear extents of the sources in the current sample are ~ 250 kpc with their spectral luminosities at 1.4 GHz in the range 2-25 ×1023 W Hz–1. The steep spectra of these sources are a result of the cessation of AGN activities in them about 15-100 million years ago. Before the cessation of AGN activity, the radio luminosities of these galaxies were ~ 1000 times brighter than their current luminosities and would have been comparable to those of the brightest active radio galaxies detected in the local universe (L 1.4 ~ 1027 W Hz–1). The dead radio galaxies reported here represent the "tip of the iceberg" and quantifying the abundance of such a population has important implications to the life cycle of the AGN.	en
dc.language.iso	en	en
dc.publisher	IOP Publishing Ltd.	en
dc.relation.uri	http://adsabs.harvard.edu/abs/2009ApJ...698L.163D	en
dc.relation.uri	http://arxiv.org/abs/0906.0223	en
dc.relation.uri	http://dx.doi.org/10.1088/0004-637X/698/2/L163	en
dc.rights	2009 The American Astronomical Society	en
dc.subject	galaxies: active	en
dc.subject	galaxies: halos	en
dc.subject	galaxies: high-redshift	en
dc.subject	radiation mechanisms: non-thermal	en
dc.subject	radio continuum: galaxies	en
dc.title	Relics of double radio sources	en
dc.type	Article	en
Appears in Collections:	Research Papers (A&A)

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