A search for variable and transient radio sources in the extended Chandra Deep Field South at 5.5 GHz

被引:28
作者
Bell, M. E. [1 ,2 ,3 ]
Huynh, M. T. [4 ]
Hancock, P. [2 ,3 ,5 ]
Murphy, Tara [2 ,3 ]
Gaensler, B. M. [2 ,3 ]
Burlon, D. [2 ,3 ]
Trott, C. [2 ,5 ]
Bannister, K. [1 ,2 ]
机构
[1] CSIRO Astron & Space Sci, Epping, NSW 1710, Australia
[2] ARC Ctr Excellence All Sky Astrophys CAASTRO, Redfern, NSW, Australia
[3] Univ Sydney, Sch Phys, Sydney Inst Astron SIfA, Sydney, NSW 2006, Australia
[4] Univ Western Australia, Int Ctr Radio Astron Res, Crawley, WA 6009, Australia
[5] Curtin Univ, Int Ctr Radio Astron Res, Bentley, WA 6845, Australia
基金
澳大利亚研究理事会;
关键词
instrumentation: interferometers; techniques: image processing; catalogues; radio continuum: general; EXTRAGALACTIC LEGACY SURVEY; ACTIVE GALACTIC NUCLEI; X-RAY; OPTICAL SPECTROSCOPY; SOURCE CATALOGS; BOOTES FIELD; VARIABILITY; SKY; SCIENCE; VIEW;
D O I
10.1093/mnras/stv882
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present a three epoch survey for transient and variables in the extended Chandra Deep Field South at 5.5 GHz with the Australia Telescope Compact Array. A region covering similar to 0.3 deg(2) was observed on time-scales of 2.5 months and 2.5 yr and typical sensitivities 12.1-17.1 mu Jy beam(-1) (1 sigma) were achieved. This survey represents the deepest search for transient and variable radio sources at 5.5 GHz. In total 124 sources were detected above the 5.5 sigma level. One highly variable radio source was found with Delta S > 50 per cent implying a surface density of similar to 3 deg(-2). A further three radio sources were found with lower levels of variability equating to a surface density of similar to 13 deg(-2) above a detection threshold of 82.3 mu Jy. All of the variable sources have inverted radio spectra (between 1.4 and 5.5 GHz) and are associated with active galactic nuclei. We conclude that these variables are young gigahertz peaked-spectrum sources with active and self-absorbed radio jets. We explore the variability completeness of this sample and conclude that the fairly low levels of variability would only be detectable in 3-25 per cent of all sources within the field. No radio transients were detected in this survey and we place an upper limit on the surface density of transient events < 7.5 deg(-2) above a detection threshold of 68.8 mu Jy.
引用
收藏
页码:4221 / 4232
页数:12
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