THREE CANDIDATE CLUSTERS OF GALAXIES AT REDSHIFT {approx}1.8: THE 'MISSING LINK' BETWEEN PROTOCLUSTERS AND LOCAL CLUSTERS?
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
- INAF-Osservatorio Astronomico di Torino, Via Osservatorio 20, I-10025 Pino Torinese (Italy)
- European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748, Garching bei Muenchen (Germany)
- INAF-Osservatorio Astronomico di Trieste, Via Tiepolo 11, I-34143 Trieste (Italy)
We present three candidate clusters of galaxies at redshifts most likely between 1.7 and 2.0, which corresponds to a fundamentally unexplored epoch of cluster evolution. The candidates were found by studying the environment around our newly selected sample of 'beacons' low-luminosity (FR I) radio galaxies in the COSMOS field. In this way, we intend to use the fact that FR Is at low z are almost invariably located in clusters of galaxies. We use the most accurate photometric redshifts available to date, derived by the COSMOS collaboration using photometry with a set of 30 filters, to look for three-dimensional space overdensities around our objects. Three out of the five FR Is in our sample which possess reliable photometric redshifts between z {sub phot} = 1.7 and 2.0 display overdensities that together are statistically significant at the 4{sigma} level, compared to field counts, arguing for the presence of rich clusters of galaxies in their Mpc environment. These first results show that the new method for finding high-z clusters we recently proposed, which makes use of low-power FR I radio galaxies instead of the more powerful FR II sources often used in the literature to date, is returning very promising candidates.
- OSTI ID:
- 21301287
- Journal Information:
- Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 710; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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