Astronomy Tea Talk

  The kinetic Sunyaev-Zel'dovich (kSZ) effect describes the Doppler shift of CMB photons scattered off of high energy electrons in the intra-cluster medium (ICM) due to the bulk motion of the ICM. The surface brightness of the kSZ signal is independent of redshift and directly proportional to the line-of-sight peculiar velocity of the ICM. It therefore promises to be a powerful cosmological probe by providing absolute velocity measurements beyond the local universe, although detecting the kSZ signal has proven to be a significant observational challenge. I will present our recent measurement of the kSZ effect signal towards the massive galaxy cluster MACS J0717.5+3745 at z=0.55 using a combination of (sub)millimeter data from the Bolocam instrument at the Caltech Submillimeter Observatory and the Herschel-SPIRE photometer, along with X-ray data from Chandra and XMM. I will also discuss the potential science reach of future kSZ measurements from facilities like CCAT.