https://doi.org/10.1051/epjconf/202225700039
Sunyaev Zel’dovich high resolution view of filamentary structures between galaxy clusters pairs
1 Sapienza University of Rome, Physics Department, Piazzale Aldo Moro 5, 00185 Rome, Italy
2 INFN - Sezione di Roma, Piazzale Aldo Moro 5 - I-00185, Rome, Italy
* e-mail: federico.radiconi@roma1.infn.it
Published online: 17 January 2022
Strong observational and theoretical evidences suggest that about half of the baryons in the Universe should lie outside galaxy clusters in a lowdensity and hot phase in filaments connecting galaxy clusters. Due to the low density, most of this filamentary plasma can not be detected by X-ray observatories. In particular cases of low redshift cluster pairs in the pre-merging phase, the Sunyaev Zel’dovich (SZ) effect can be used to observe the intercluster regions and detect the imprint of missing baryons.
The Abell 399-401 (A399-401) system is the perfect laboratory to test our ability to detect filamentary structures via the SZ effect with <~ 1′ angular resolution. This pair has been well studied at several frequencies: it exhibits double radio-halos, an excess of X-ray emission in the intercluster region and a synchrotron radio ‘ridge’ connecting the two clusters. Moreover the Planck satellite provided the first SZ detection of the gas between A399-401 despite the poor angular resolution (~ 10′) of its SZ map.
We have used an Atacama Cosmology Telescope (ACT) and Planck satellite Compton-y map (1:65′ angular resolution) that combines ACT data from 2008 to 2019 with Planck maps to study the A399-401 system in detail. We present the data analysis and results.
© The Authors, published by EDP Sciences, 2022
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
