Astronomy and Astrophysics – Astrophysics
Scientific paper
2001-10-04
Mon.Not.Roy.Astron.Soc. 330 (2002) 17
Astronomy and Astrophysics
Astrophysics
19 pages LaTeX, including 8 figures. Accepted for publication in MNRAS. Version with higher resolution figures available from
Scientific paper
10.1046/j.1365-8711.2002.05023.x
An extremely deep 5 GHz radio observation is presented of the rich cluster MS1054-03 at redshift z=0.83. 34 radio sources are detected down to a 32 micro-Jy (6 sigma), compared to about 25 expected from previous blank field radio source count determinations; the sources giving rise to these excess counts lie within 2 arcmins (700 kpc) of the cluster centre. Existing imaging and spectroscopy has provided optical identifications for 21 of the radio sources and redshifts for 11, of which 8 are confirmed cluster members. 4 of these 8 confirmed cluster sources are associated with close galaxy pairs (10-25 kpc projected offset) of similar magnitude, implying that the radio source may be triggered by an interaction. However, although MS1054-03 has a very high fraction (17%) of on-going mergers (separations <~ 10 kpc), no radio emission is detected towards any of these merger events, setting a mean upper limit of 10 Msun/yr for any star formation associated with these mergers. This supports a hypothesis that low luminosity radio sources may be onset by initial weak interactions rather than direct mergers. The host galaxies of the other four confirmed cluster radio sources are all isolated, and show a range of morphologies from early-type to Sc. A comparison between the emission line and radio luminosities suggests that two of these four radio sources are low-luminosity AGN, whilst for at least one of the other two the radio emission is associated with on-going star formation. All of the radio sources associated with the galaxy pairs appear more likely AGN than starburst origin. The overall proportion of radio sources associated with AGN in this cluster (>75%) is higher than at these flux density levels in the field (40-50%).
Best Philip N.
Franx Marijn
R"ottgering Huub J. A.
van Dokkum Pieter G.
No associations
LandOfFree
Micro-Jy radio sources in the z=0.83 cluster MS1054-03 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Micro-Jy radio sources in the z=0.83 cluster MS1054-03, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Micro-Jy radio sources in the z=0.83 cluster MS1054-03 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-193382