1995/12/07 by Sebastian M. Pascarelle, S. M. Pascarelle,, R. A. Windhorst, +7 · 79 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Brightest cluster galaxy #Cluster (spacecraft) #Context (archaeology) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Galaxy group #Radio Astronomy Observations and Technology #Radio galaxy #Redshift #astro-ph
paper · pdf · doi:10.1086/309852
published in The Astrophysical Journal 456(1) (IOP Publishing) · Accepted for publication in The Astrophysical Journal (Letters). 13 pages of gzip compressed and uuencoded PS. Figures are available at http://www.phys.unsw.edu.au/~spd/bib.html
arxiv created 1995/12/07 · openalex publication_date 1996/01/01 · openalex created_date 2016/06/24 · arxiv updated 2016/08/30 · openalex updated_date 2026/08/05
We report the serendipitous discovery of a group or cluster of young galaxies at z ≃ 2.40 in a 24 orbit Hubble Space Telescope /WFPC2 exposure of the field around the weak radio galaxy 53W002. Potential cluster members were identified on ground-based narrowband redshifted Lyα images and confirmed via spectroscopy. In addition to the known weak radio galaxy 53W002 at z = 2.390, two other objects were found to have excess narrowband Lyα emission at z ≃ 2.40. Both have been spectroscopically confirmed, and one clearly contains a weak active galactic nucleus (AGN). They are located within 1' of 53W002 or ~0.23 h 100 −1 Mpc ( q 0 = 0.5) at z ≃ 2.40, which is the physical scale of a group or small cluster of galaxies. Profile fitting of the WFPC2 images shows that the objects are very compact, with scale lengths ≃ 0 1 (≃0.39 h 100 −1 kpc), and are rather faint (luminosities < L *), implying that they may be subgalactic-sized objects. We discuss these results in the context of galaxy and cluster evolution and the role that weak AGNs may play in the formation of young galaxies.