• The MACS team
• Project overview
• The sample
• Publications

The MACS team:

• Harald Ebeling, University of Hawaii, USA
• Alastair Edge, University of Durham, UK
• J. Patrick Henry, University of Hawaii, USA

• Nick Kaiser, University of Hawaii, USA
• Leon Van Speybroeck, SAO/CfA, Cambridge, MA, USA
• Alastair Edge, University of Durham, UK
• Jean-Paul Kneib, OMP, Marseille, France
• Johan Richard, University of Durham, UK
• Cheng-Jiun Ma, CfA, Cambridge, MA, USA
• Marceau Limousin, OMP, Marseille, France
• Adam Mantz, GSFC, USA

Project overview:

The MAssive Cluster Survey (MACS) is an ongoing project aimed at the compilation and characterization of a statistically complete sample of very X-ray luminous (and thus, by inference, massive), distant clusters of galaxies. The primary goal of MACS was to increase the number of known massive clusters at z > 0.3 from a handful to a hundred. The final MACS cluster sample has greatly improved our ability to study quantitatively the physical and cosmological parameters driving cluster evolution at redshifts and luminosities poorly sampled by all previous cluster surveys.

To achieve these goals we applied an X-ray flux and X-ray hardness-ratio cut to select distant cluster candidates from the ROSAT Bright Source Catalogue. Starting from a list of more than 5,000 X-ray sources within the survey area of 22,735 square degrees we use positional cross-correlations with public catalogues of Galactic and extragalactic objects, reference to APM colours, visual inspection of Digitized Sky Survey images, extensive CCD imaging, and finally spectroscopic observations with the University of Hawaii's 2.2m and the Keck 10m telescopes to compile the final cluster sample.

The MACS cluster sample comprises 124 spectroscopically confirmed clusters at 0.3 < z < 0.7; more than two thirds of these are new discoveries. This sample is over 20 times larger than that of the EMSS in the same redshift and X-ray luminosity range.

Comprehensive follow-up observations of MACS clusters were launched as the survey proceeded. These follow-up efforts include: V,R,I band imaging with the University of Hawaii's 2.2m telescope, weak-lensing mass measurements using wide-field imaging data obtained with the prime focus camera of the Subaru 8m telescope, virial mass estimates based on cluster galaxy velocity dispersions measured with the CFHT 3.6m and Keck-I 10m telescopes, SZ observations with the BIMA mm-wave radio interferometer, measurements of the cluster gas and temperature distribution via deep pointed X-ray observations with the ACIS instrument aboard the Chandra X-ray Observatory, and both deep, multi-passband and snapshot images with the Hubble Space Telescope.

The sample:

The Lx-z distribution of MACS clusters is shown in the following figure.

The compilation of statistically complete subsets of the MACS sample was pursued both as a function of redshift and of X-ray flux. The sample of the 12 most distant MACS clusters (z>0.5) was published in 2007, and the 34 X-ray brightest ones were the subject of a 2010 paper. We continue to conduct follow-up studies on many individually exciting systems (such as MACSJ0717.5+3745).

Selected MACS publications:

• Ebeling H., Edge A.C., Henry J.P. 2000, MACS: A quest for the most massive galaxy clusters in the universe, 2001, ApJ, 553, 668

• LaRoque S.J., Joy M., Carlstrom J.E., Ebeling H., Dawson K.S., Edge A., Holzapfel W.L., Miller A.D., Nagai D., Patel S.K., Reese E.D. Sunyaev-Zel'dovich Effect imaging of MACS galaxy clusters at z>0.5, 2003, ApJ, 583, 559

• Edge A.C., Ebeling H., Bremer M., Röttgering H., van Haarlem M., Rengelink R., Courtney N. The discovery of two distant, massive clusters of galaxies in the ROSAT All-Sky Survey, 2003, MNRAS, 339, 913

• Allen S.W., Schmidt R.W., Ebeling H., Fabian A.C., van Speybroeck L. Constraints on dark energy form Chandra observations of the largest relaxed galaxy clusters, 2004, MNRAS, 353, 457

• Ebeling H., Barrett E., Donovan D. Discovery of a large-scale filament connected to the massive galaxy cluster MACSJ0717.5+3745 at z=0.55, 2004, ApJ, 609, L49

• Ruderman J.T. & Ebeling H. The Origin of the Spatial Distribution of X-ray luminous AGN in Massive Galaxy Clusters, 2005, ApJ, 623, L81

• Smail I., Swinbank A.M., Richard J., Ebeling H., Kneib J.-P., Edge A.C., Stark D., Ellis R.S., Dye S., Smith G.P., Mullis C. A very bright, highly magnified Lyman-break galaxy at z=3.07, 2007, ApJL, 654, L33

• Stott J.P., Smail I., Edge A.C., Ebeling H., Smith G.P., Kneib J.-P., Pimbblet K.A. An increase in the faint red galaxy population in massive clusters since z~0.5, 2007, ApJ, 661, 95

• Ebeling H., Barrett E., Donovan D., Ma C.-J., Edge A.C., van Speybroeck L. A complete sample of 12 very X-ray luminous galaxy clusters at z>0.5, 2007, ApJ, 661, L33

• Mantz A., Allen S.W., Ebeling H., Rapetti D. New constraints on dark energy from the observed growth of the most X-ray luminous galaxy clusters, 2008, MNRAS, 387, 1179

• Ma C.-J., Ebeling H., Donovan D., Barrett E. The spatial distribution of galaxies of different spectral types in the massive intermediate-redshift cluster MACSJ0717.5+3745, 2008, ApJ, 684, 160

• Kartaltepe J.S., Ebeling H., Ma C.-J., Donovan D. Probing the large-scale structure around distant MACS clusters, 2008, MNRAS, 389, 1240

• Bradac M., Allen S.W., Treu T., Ebeling H., Massey R., Morris R.G., von der Linden A., Applegate D. Revealing the properties of Dark Matter in the merging cluster MACS J0025.4-1222, 2008, ApJ, 687, 959

• Ma C.-J., Ebeling H., Barrett E. An X-ray/optical study of the complex dynamics of the core of the massive intermediate-redshift cluster MACSJ0717.5+3745, 2009, ApJ, 693, L56

• Ebeling H., Ma C.J., Kneib J.-P., Jullo E., Courtney N.J.D., Barrett E. Edge A.C., Le Borgne J.-F. A spectacular giant arc in the massive cluster lens MACS J1206-0847, 2009, MNRAS, 395, 1213

• Bonafede A., Feretti L., Giovannini G., Govoni F., Murgia M., Taylor G.B., Ebeling H., Allen S., Gentile G., Pihlstr\"{o}m Y. Revealing the magnetic field in a distant galaxy cluster: the complex radio emission from MACSJ0717.5+3745, 2009, A&A, 503, 707

• Smith G.P., Ebeling H., Limousin M., Kneib J.-P., Swinbank A.M., Ma C.-J., Jauzac M. Richard J., Jullo E., Sand D.J., et al. Hubble Space Telescope observations of a spectacular new strong-lensing galaxy cluster: MACSJ1149.5+2223 at z=0.544, 2009 ApJ, 707, L163

• Limousin M., Ebeling H., Ma C.-J., Swinbank A.M., Smith G.P., Richard J., Edge A.C., Jauzac M., Kneib J.-P., Marshall P., Schrabback T. MACSJ1423.8+2404: Gravitational lensing by a massive, relaxed cluster of galaxies at z=0.54, 2010, MNRAS, 405, 777

• Ebeling H., Edge A.C., Mantz A., Barrett E., Henry J.P., Ma C.-J., van Speybroeck L. The X-ray brightest clusters of galaxies from the Massive Cluster Survey, 2010, MNRAS, in press

• Ma, C.-J., Ebeling H., Marshall P., Schrabback T. The impact of a major cluster merger on galaxy evolution in MACSJ0025.4-1225, 2010, MNRAS, 406, 121

• Horesh A., Maoz D., Ebeling H., Seidel G., Bartelmann M. The lensing efficiencies of MACS X-ray selected versus RCS optically selected galaxy clusters, 2010, MNRAS, 406, 1318

(page last updated August, 2010 by H. Ebeling)