GCLASS is a follow-up spectroscopic (and imaging) survey of ten of the richest SpARCS clusters at z~1, nine of which are shown on the left.
It is one of the largest surveys ever carried out on the Gemini North and South telescopes,
totaling 220 hours (25 nights) with half of the time coming from the US (PI: Wilson) and half from Canada (PI: Yee).
The survey is now complete, and has obtained spectra for ~50 members per cluster, an unprecendented number at such high redshift.
``The Gemini CLuster Astrophysics Spectroscopic Survey (GCLASS)", Invited Talk, Gemini Science Meeting 2012
Important findings so far:
``Nature'' (stellar mass) and ``nurture'' (environment) both have a role to play in quenching star formation in galaxies. See Gemini Web Release.
Brightest Cluster Galaxies (BCGs) are found to grow significantly in stellar mass (factor of two since z=1), see August 2102 AAO Observer Newsletter ``Science Highlights". Star formation rates in BCGs at z~1 are too low to result in significant mass growth. Instead, it is likely that most of the mass build up occurs through dry mergers. Both major and minor mergers are likely important, but the majority of build up seems to be occurring through major mergers, see August 2013 AAO Observer Newsletter ``Science Highlights".
MIPS cluster members are an infalling population, recently accreted from the field.
Full list of GCLASS publications:
``The Phase Space and Stellar Populations of Cluster Galaxies at z~1: Simultaneous Constraints on the Location and Timescale of Satellite Quenching''
Muzzin, A., van der Burg, R. F. J., McGee, S. L., Balogh, M., Franx, M., Hoekstra, H., Hudson, M. J., Noble, A.,
Webb, T., Wilson G. & Yee, H. K. C., 2014, ApJ, 796, 65
``A Census of Stellar Mass in 10 Massive Haloes at z~1 from the GCLASS Survey''
van der Burg, R. F. J., Muzzin A., Hoekstra, H., Wilson, G, Lidman, C. & Yee, H. K. C., 2014, A&A, 561, A79
``The environmental dependence of the stellar mass function at z ~ 1. Comparing cluster and field between the GCLASS and UltraVISTA surveys''
van der Burg, R., Muzzin A., Hoekstra, H., Lidman, C., Rettura, A., Wilson, G, Yee, H. K. C., Hildebrandt, H. Marchesini, Stefanon, D. M., Demarco, R. & Kuijken, K., 2013, A&A, 557, A15
``A Kinematic Approach To Assessing Environmental Effects: Star-Forming Galaxies in a z~0.9 SpARCS cluster using Spitzer 24 micron Observations''
Noble, A. G., Webb, T. M. A., Muzzin, A., Wilson G, Yee, H. K. C., van der Berg, R. F. J. 2013, ApJ, 768, 118
``The importance of major mergers in the build up of stellar mass in brightest cluster galaxies at z=1''
Lidman, C., Iacobuta, G., Bauer, A. E., Cerulo, P., Couch, W. J., Delaye, L., Demarco, R., Huertas-Company, R., Mei, S., Meyers, J., Muzzin, A., Noble, A, Nantais, J., Rettura, A., Rosati, P., Sanchex-Janssen, R, Strazzullo, V., Webb, T. M. A., Wilson, G., & Yee, H. K. C., 2013, MNRAS, 433, 827
``Evidence for Significant Growth in the Stellar Mass of Brightest Cluster Galaxies over the Past 10 Billion Years''
Lidman, C., Suherli, J., Muzzin A., Wilson G, Demarco, R., Brough, S., Rettura, A., Cox., J., DeGroot, A., Yee, H. K. C., Gilbank, D., Hoekstra, H., Balogh, M., Ellingson, E., Hicks, A., Nantais, J., Noble, A., Lacy, M., Surace J., and Webb, T., 2012, MNRAS, 427, 550
``The Gemini Cluster Astrophysics Spectroscopic Survey (GCLASS): The Role of Environment and Self-regulation in Galaxy Evolution at z ~ 1''
Muzzin A., Wilson G, Yee H. K. C., Gilbank, D., Hoekstra, H., Demarco, R., Balogh, M., van Dokkum, P., Franx., M., Ellingson, E., Hicks, A., Nantais, J., Noble, A., Lacy, M., Lidman, C., Rettura, A., Surace J., and Webb, T., 2012, ApJ, 746, 188
``Spectroscopic Confirmation of Three Red-Sequence Selected Galaxy Clusters at z = 0.87, 1.16, and 1.21 from the SpARCS Survey''
Demarco R., Wilson G, Muzzin A., Lacy M., Surace J., Yee H. K. C., Hoekstra H., Blindert K., & Gilbank D., 2010, ApJ, 711, 1185
``Spectroscopic Confirmation of a Massive Red-Sequence Selected Galaxy Cluster at z = 1.34 in the SpARCS-South Cluster Survey''
Wilson G., Muzzin A., Yee H. K. C., Lacy M., Surace J., Gilbank D, Blindert, K., Hoekstra H., Majumdar, S., Demarco, R., Gardner J. P., Gladders M. D., & Lonsdale, C., 2009, ApJ, 698, 1943
``Spectroscopic Confirmation of Two Massive Red-Sequence Selected Galaxy Clusters at z ~ 1.2 in the SpARCS-North Cluster Survey''
Muzzin A., Wilson G., Yee H. K. C., Hoekstra H., Gilbank D, Surace J., Lacy M., Blindert, K., Majumdar, S., Demarco, R., Gardner J. P., Gladders M. D., & Lonsdale, C., 2009, ApJ, 698, 1934