Vol 4, No 6

A Peculiar Broad Line Radio Galaxy 1938--155: VLA Observation at 90 cm

Tao An, Xiao-Yu Hong, Wen-Xia Feng, Jun-Hui Zhao


Abstract We observed 1938-155, a broad line radio galaxy (BLRG), with the Very Large Array (VLA) at 90cm with an angular resolution of 6.8'' × 4.0''. The source consists of two components separated by 4 arcsec (∼ 20kpc, for H0 = 65km s-1 Mpc-1, q0=0.5) along the SE-NW direction. Both components show steep-spectra with a similar spectral index α∼ 0.83 ± 0.07 (Sν∝ν-α). The bright double components are surrounded by a low-brightness cocoon. The radio properties of the two bright components are consistent with the hot spots produced by twin jets. An upper limit of ∼ 0.0008 for the core dominance parameter (R) is inferred, suggesting there is no prominent radio core in the source. Assuming a modest viewing angle 30, a jet velocity is estimated ∼ 0.07 c, based on the jet to counter-jet brightness ratio (J). The lower limit in jet speed inferred is consistent with no Doppler beaming effect on the jet. The radio galaxy 1938-155 could be an exceptional BLRG with no prominent radio core or jet.


Keywords Galaxy: quasar: individual -- radio continuum: VLA

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