Imaging Simulations of the Sunyaev-Zel'dovich Effect for ALMA

TL;DR

This paper simulates how ALMA can image the Sunyaev-Zel'dovich effect in galaxy clusters, highlighting the capabilities and limitations of different configurations and frequencies for studying intracluster phenomena.

Contribution

It provides detailed imaging simulations of the SZ effect with ALMA, assessing the impact of array configurations and frequency bands on image quality and efficiency.

Findings

ALMA's compact configuration can resolve intracluster medium at 90GHz.

Adding ACA significantly improves image reconstruction quality.

Higher frequencies above 100 GHz are less efficient for SZ mapping.

Abstract

We present imaging simulations of the Sunyaev-Zel'dovich effect of galaxy clusters for the Atacama Large Millimeter/submillimeter Array (ALMA) including the Atacama Compact Array (ACA). In its most compact configuration at 90GHz, ALMA will resolve the intracluster medium with an effective angular resolution of 5 arcsec. It will provide a unique probe of shock fronts and relativistic electrons produced during cluster mergers at high redshifts, that are hard to spatially resolve by current and near-future X-ray detectors. Quality of image reconstruction is poor with the 12m array alone but improved significantly by adding ACA; expected sensitivity of the 12m array based on the thermal noise is not valid for the Sunyaev-Zel'dovich effect mapping unless accompanied by an ACA observation of at least equal duration. The observations above 100 GHz will become excessively time-consuming owing to the narrower beam size and the higher system temperature. On the other hand, significant improvement of the observing efficiency is expected once Band 1 is implemented in the future.