SALT spectroscopic observations of galaxy clusters detected by ACT and a type II quasar hosted by a brightest cluster galaxy

Brian Kirk, Matt Hilton, Catherine Cress, Steven M. Crawford, John P. Hughes, Nicholas Battaglia, J. Richard Bond, Claire Burke, Megan B. Gralla, Amir Hajian, Matthew Hasselfield, Adam D. Hincks, Leopoldo Infante, Arthur Kosowsky, Tobias A. Marriage, Felipe Menanteau, Kavilan Moodley, Michael D. Niemack, Jonathan L. Sievers, Cristóbal SifónSusan Wilson, Edward J. Wollack, Caroline Zunckel

Research output: Contribution to journalArticle

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We present SouthernAfrican Large Telescope follow-up observations of sevenmassive 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 < z < 0.55, range in mass from (5-20) × 1014 M (M200c). Their masses, given their SZ signals, are similar to those of Southern hemisphere ACT clusters previously observed using Gemini and the VLT. We note that the brightest cluster galaxy in one of the systems studied, ACT-CL J0320.4+0032 at z = 0.38, hosts a type II quasar. Only a handful of such systems are currently known, and therefore ACT-CL J0320.4+0032 may be a rare example of a very massive halo in which quasar-mode feedback is actively taking place.

Original languageEnglish (US)
Pages (from-to)4010-4026
Number of pages17
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Mar 21 2015


All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Kirk, B., Hilton, M., Cress, C., Crawford, S. M., Hughes, J. P., Battaglia, N., Richard Bond, J., Burke, C., Gralla, M. B., Hajian, A., Hasselfield, M., Hincks, A. D., Infante, L., Kosowsky, A., Marriage, T. A., Menanteau, F., Moodley, K., Niemack, M. D., Sievers, J. L., ... Zunckel, C. (2015). SALT spectroscopic observations of galaxy clusters detected by ACT and a type II quasar hosted by a brightest cluster galaxy. Monthly Notices of the Royal Astronomical Society, 449(4), 4010-4026.