# The Far-Infrared-Radio Correlation in MS0451-03

**Authors:** S. M. Randriamampandry, S. M. Crawford, C. M. Cress, K. M. Hess, M. Vaccari, E. M. Wilcots, M. A. Bershady, G. D. Wirth  
**arXiv:** [1411.3677](https://arxiv.org/abs/1411.3677)  
**Date:** 2014-11-13  
**Summary page:** https://www.summarizepaper.com/en/paper/1411.3677v1/

## Key points

- Multi-wavelength analysis of star-forming galaxies in the cluster MS0451.6-0305 at redshift 0.54
- Objective: Gain insights into the evolution of the far-infrared-radio relationship in distant rich clusters
- Total infrared luminosities derived for cluster and field galaxies using empirical relation based on Spitzer MIPS 24 μm photometry
- Radio flux densities measured from Very Large Array 1.4 GHz radio continuum observations
- Far-infrared to radio luminosity ratio for galaxies in this cluster: qFIR = 1.80±0.15 with a dispersion of 0.53; no change observed with redshift or environment due to large intrinsic dispersion
- Higher percentage (27% ±23%) of galaxies in this cluster exhibit excess radio flux compared to low redshift clusters (11%)
- Cluster enhancement of radio-excess sources at earlier epoch, specifically blue galaxies associated with active star formation
- Far-infrared-radio relationship for blue galaxies: qFIR = 2.01±0.14 with a dispersion of 0.35, consistent with predicted value from field relationship
- Findings contribute to understanding far-infrared-radio relationship in distant rich clusters and highlight potential influence of cluster environments on radio-excess sources
- Further studies involving larger samples and multiple clusters needed for confirmation and more robust conclusions

## Summary

In this study, the authors present a multi-wavelength analysis of star-forming galaxies in the massive cluster MS0451.6-0305 at a redshift of approximately 0.54 with the main objective of gaining new insights into the evolution of the far-infrared-radio relationship in distant rich clusters. To achieve this, they derive total infrared luminosities for a sample of cluster and field galaxies that have been spectroscopically confirmed using an empirical relation based on $Spitzer$ MIPS 24 $\mu$m photometry. Additionally, radio flux densities are measured from deep Very Large Array 1.4 GHz radio continuum observations. The results show that the ratio of far-infrared to radio luminosity for galaxies in this intermediate redshift cluster is found to be $q_{\rm FIR}$ = 1.80$\pm$0.15 with a dispersion of 0.53 and no observable change in this value is detected with either redshift or environment due to the large intrinsic dispersion. However, it is worth noting that a higher percentage (27% ±23%) of galaxies in this cluster exhibit an excess in their radio fluxes compared to low redshift clusters (11%). This suggests a possible cluster enhancement of radio-excess sources at this earlier epoch when considering blue galaxies specifically which are typically associated with active star formation; the far-infrared-radio relationship ($q_{\rm FIR}$ = 2.01$\pm$0.14 with a dispersion of 0.35) is consistent with the predicted value from the field relationship. Overall, these findings contribute to our understanding of the far-infrared-radio relationship in distant rich clusters and highlight the potential influence of cluster environments on radio-excess sources; however, further studies involving larger samples and multiple clusters would be valuable for confirming these results and providing more robust conclusions.