Researchers using the Atacama Large Millimeter/submillimeter Array (ALMA) successfully imaged a radio "hole" around a galaxy cluster 4.8 billion light-years away from us. This is the highest resolution image ever taken of such a hole caused by the Sunyaev-Zel'dovich effect (SZ effect). The image proves ALMA's high capability to investigate the distribution and temperature of gas around galaxy clusters through the SZ effect. A research team led by Tetsu Kitayama, a professor at Toho University, Japan, used ALMA to investigate the hot gas in a galaxy cluster. The hot gas is a key component to understand the nature and evolution of galaxy clusters. Even though the hot gas does not emit radio waves detectable with ALMA, the gas scatters the radio waves of the Cosmic Microwave Background and makes a "hole" around the galaxy cluster. This is the Sunyaev-Zel'dovich effect Read more
Title: CARMA Measurements of the Sunyaev-Zel'dovich Effect in RXJ1347.5-1145 Authors: Thomas J. Plagge, Daniel P. Marrone, Zubair Abdulla, Massimiliano Bonamente, John E. Carlstrom, Megan Gralla, Christopher H. Greer, Marshall Joy, James W. Lamb, Erik M. Leitch, Adam Mantz, Stephen Muchovej, David Woody
We demonstrate the Sunyaev-Zel'dovich (SZ) effect imaging capabilities of the Combined Array for Research in Millimetre-wave Astronomy (CARMA) by presenting an SZ map of the galaxy cluster RXJ1347.5-1145. By combining data from multiple CARMA bands and configurations, we are able to capture the structure of this cluster over a wide range of angular scales, from its bulk properties to its core morphology. We find that roughly 9% of this cluster's thermal energy is associated with sub-arcminute-scale structure imparted by a merger, illustrating the value of high-resolution SZ measurements for pursuing cluster astrophysics and for understanding the scatter in SZ scaling relations. We also find that the cluster's SZ signal is lower in amplitude than suggested by a spherically-symmetric model derived from X-ray data, consistent with compression along the line of sight relative to the plane of the sky. Finally, we discuss the impact of upgrades currently in progress that will further enhance CARMA's power as an SZ imaging instrument.