Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published August 2006 | Published
Journal Article Open

Deep spectroscopy of 9C J1503+4528: a very young compact steep spectrum radio source at z= 0.521


9C J1503+4528 is a very young compact steep spectrum radio galaxy, with an age of the order of 10^4 yr. This source is therefore an ideal laboratory for the study of the intrinsic host galaxy/intergalactic medium properties, interactions between the radio source and surrounding interstellar medium, links between star formation and active galactic nucleus (AGN) activity and the radio source triggering mechanism. Here we present the results of a spectroscopic analysis of this source, considering each of these aspects of radio source physics. We find that shock ionization by the young radio source is important in the central regions of the galaxy on scales similar to that of the radio source itself, whilst evidence for an AGN ionization cone is observed at greater distances. Line and continuum features require the presence of a young stellar population (YSP), the best-fitting model for which implies an age of 5 × 10^6 yr, significantly older than the radio source. Most interestingly, the relative sizes of radio source and extended emission-line region suggest that both AGN and radio source are triggered at approximately the same time. If both the triggering of the radio source activity and the formation of the YSP had the same underlying cause, this source provides a sequence for the events surrounding the triggering process. We propose that the AGN activity in 9C J1503+4528 was caused by a relatively minor interaction, and that a supermassive black hole powering the radio jets must have been in place before the AGN was triggered.

Additional Information

© 2006 The Authors. Journal compilation © 2006 RAS. Accepted 2006 May 17. Received 2006 May 4; in original form 2006 April 3. Article first published online: 4 Aug. 2006. We thank Clive Tadhunter & Joanna Holt for useful discussions and allowing us to develop the CONFIT software for our own use; Daniel Smith and Matt Jarvis for obtaining the r-band image and Andy Adamson for obtaining the K-band image. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The observatory was made possible by the generous financial support of the W. M. Keck Foundation. UKIRT is operated by the Joint Astronomy Centre on behalf of PPARC. KJI acknowledges a PPARC research fellowship, DL a PPARC PhD studentship and GC support from PPARC observational rolling grant PPA/G/O/2003/00123. It is a pleasure to express our gratitude and respect to the indigenous people of Hawaii, from whose sacred mountain Mauna Kea our observations were made. We thank the anonymous referee for his/her very useful comments on this paper.

Attached Files

Published - INSmnras06.pdf


Files (4.9 MB)
Name Size Download all
4.9 MB Preview Download

Additional details

August 22, 2023
October 23, 2023