NOAO > Observing Info > Approved Programs > 2012B-0138
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NOAO > Observing Info > Approved Programs > 2012B-0138 |
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PI: Sean McGee, University of Durham, s.l.mcgee@durham.ac.uk
Address: Department of Physics, South Road, Durham DH1 3LE, United Kingdom
CoI: Michael Balogh, University of Waterloo
CoI: Roderik Overzier, University of Texas
CoI: Yi-Kuan Chiang, University of Texas
CoI: Nina Hatch, University of Nottingham
CoI: George Miley, Leiden University
CoI: Bram Venemans, ESO
Title: The high redshift progenitors of massive galaxy clusters
Abstract:
We shall trace the development of galaxy clusters from 5 > z > 2 using high-z
radio galaxies (HzRGs) as beacons. The most luminous HzRGs are associated
with progenitors of brightest cluster galaxies and pinpoint high-density
regions in the early Universe - the likely ancestors of typical rich
clusters. Because protoclusters contain large numbers of galaxies at the same
z, they are prime laboratories for evolution studies. Bright Lyman alpha
emitting (LAE) protocluster members provide bright tracers of these
environments, and unique kinematical information. As part of an earlier large
programme on the VLT, we previously determined LAE redshifts for 151 objects
in 6 HzRG fields that were overdense by a factor 3 - 5. Within this small
sample there is an intriguing trend for protocluster velocity dispersions to
increase from 300 km/s to 1000 km/s between z=5 and z=2, consistent with
evolutionary models. We now propose narrow band GMOS imaging, using existing
and custom-built filters, to measure LAE overdensities in the field of six
northern HzRG over two semesters. Combined with a VLT programme for 14 new
southern targets, we aim to increase the current sample of z>2 protoclusters
by a factor of four. These systems will be followed up in future semesters
with multiobject spectroscopy (including GMOS for the northern targets) of
candidate protocluster galaxies to study internal protocluster kinematics,
determine the frequency of sub-clustering, confirm the decrease of velocity
dispersion with z, investigate evolutionary trends in sizes of LAE halos,
relate halo morphologies to the protocluster hosts, and study the evolution
of protocluster populations.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2012B-0138 |
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