The Atacama Cosmology Telescope: High-resolution Sunyaev-Zel'dovich Array observations of ACT SZE-Selected clusters from the equatorial strip

Erik D. Reese, Tony Mroczkowski, Felipe Menanteau, Matt Hilton, Jonathan Sievers, Paula Aguirre, John William Appel, Andrew J. Baker, J. Richard Bond, Sudeep Das, Mark J. Devlin, Simon R. Dicker, Rolando Dünner, Thomas Essinger-Hileman, Joseph W. Fowler, Amir Hajian, Mark Halpern, Matthew Hasselfield, J. Colin Hill, Adam D. HincksKevin M. Huffenberger, John P. Hughes, Kent D. Irwin, Jeff Klein, Arthur Kosowsky, Yen Ting Lin, Tobias A. Marriage, Danica Marsden, Kavilan Moodley, Michael D. Niemack, Michael R. Nolta, Lyman A. Page, Lucas Parker, Bruce Partridge, Felipe Rojas, Neelima Sehgal, Cristóbal Sifón, David N. Spergel, Suzanne T. Staggs, Daniel S. Swetz, Eric R. Switzer, Robert Thornton, Hy Trac, Edward J. Wollack

Research output: Contribution to journalArticlepeer-review


We present follow-up observations with the Sunyaev-Zel'dovich Array (SZA) of optically confirmed galaxy clusters found in the equatorial survey region of the Atacama Cosmology Telescope (ACT): ACT-CL J0022-0036, ACT-CL J2051+0057, and ACT-CL J2337+0016. ACT-CL J0022-0036 is a newly discovered, massive (≃ 1015 M), high-redshift (z = 0.81) cluster revealed by ACT through the Sunyaev-Zel'dovich effect (SZE). Deep, targeted observations with the SZA allow us to probe a broader range of cluster spatial scales, better disentangle cluster decrements from radio point-source emission, and derive more robust integrated SZE flux and mass estimates than we can with ACT data alone. For the two clusters we detect with the SZA we compute integrated SZE signal and derive masses from the SZA data only. ACT-CL J2337+0016, also known as A2631, has archival Chandra data that allow an additional X-ray-based mass estimate. Optical richness is also used to estimate cluster masses and shows good agreement with the SZE and X-ray-based estimates. Based on the point sources detected by the SZA in these three cluster fields and an extrapolation to ACT's frequency, we estimate that point sources could be contaminating the SZE decrement at the ≲ 20% level for some fraction of clusters.

Original languageEnglish (US)
Article number12
JournalAstrophysical Journal
Issue number1
StatePublished - May 20 2012
Externally publishedYes


  • X-rays: galaxies: clusters
  • cosmic background radiation
  • cosmology: observations
  • galaxies: clusters: general
  • techniques: interferometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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