MNRAS 449, 4010–4026 (2015) doi:10.1093/mnras/stv595
SALT spectroscopic observations of galaxy clusters detected by ACT and a type II quasar hosted by a brightest cluster galaxy
Brian Kirk,1,2 Matt Hilton,1,3‹ Catherine Cress,2,4 Steven M. Crawford,5 John P. Hughes,6 Nicholas Battaglia,7 J. Richard Bond,8 Claire Burke,1 Megan B. Gralla,9 Amir Hajian,8 Matthew Hasselfield,10 Adam D. Hincks,11 Leopoldo Infante,12 Arthur Kosowsky,13 Tobias A. Marriage,9 Felipe Menanteau,14 1 15 16 17 Kavilan Moodley, Michael D. Niemack, Jonathan L. Sievers, Cristobal´ Sifon,´ Downloaded from https://academic.oup.com/mnras/article/449/4/4010/1202682 by guest on 26 March 2021 Susan Wilson,1 Edward J. Wollack18 and Caroline Zunckel16 1Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban 4041, South Africa 2Centre for High Performance Computing, CSIR Campus, 15 Lower Hope St Rosebank, Cape Town 7700, South Africa 3Centre for Astronomy and Particle Theory, School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK 4Department of Physics, University of Western Cape, Bellville 7530, Cape Town, South Africa 5South African Astronomical Observatory, PO Box 9, Observatory 7935, Cape Town, South Africa 6Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019, USA 7McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA 8Canadian Institute for Theoretical Astrophysics, 60 St George, Toronto, ON M5S 3H8, Canada 9Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St, Baltimore, MD 21218, USA 10Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544, USA 11Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada 12Departamento de Astronom´ıa y Astrof´ısica, Pontific´ıa Universidad Catolica,´ Casilla 306, Santiago 22, Chile 13Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA 14National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, 1205 W. Clark St, Urbana, IL 61801, USA 15Department of Physics, Cornell University, Ithaca, NY 14853, USA 16Astrophysics and Cosmology Research Unit, School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4041, South Africa 17Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden, the Netherlands 18NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA
Accepted 2015 March 16. Received 2015 February 24; in original form 2014 October 29
ABSTRACT We present Southern African Large Telescope follow-up observations of seven massive clusters detected by the Atacama Cosmology Telescope (ACT) on the celestial equator using the Sunyaev–Zel’dovich (SZ) effect. We conducted multi-object spectroscopic observations with the Robert Stobie Spectrograph in order to measure galaxy redshifts in each cluster field, determine the cluster line-of-sight velocity dispersions, and infer the cluster dynamical masses. We find that the clusters, which span the redshift range 0.3