# The relationship between star formation rate and radio synchrotron luminosity at 0 < z < 2

**Authors:** Timothy Garn, David A. Green, Julia M. Riley, Paul Alexander  
**arXiv:** [0905.1218](https://arxiv.org/abs/0905.1218)  
**Date:** 2009-05-08  
**Summary page:** https://www.summarizepaper.com/en/paper/0905.1218v1/

## Key points

- Study investigates the relationship between star formation rate (SFR) and radio synchrotron luminosity in galaxies at redshifts between 0 and 2
- Aim is to examine assumptions in calculating star formation history of the Universe using deep radio observations
- New observations from GMRT at a frequency of 610 MHz combined with previous surveys to create a sample of galaxies with redshift and SFR information
- Test whether local relationship between SFR and radio luminosity applies to galaxies at redshift 2
- Investigate evolution in relationship with redshift and SFR to determine consistency of physical processes leading to synchrotron radiation
- Results show local calibration can be applied successfully to high-redshift, high-SFR galaxies selected through radio observations
- Some sources exhibit evidence of inaccurate estimations of SFR, possibly due to recent onset starburst activity or suppression of radio luminosity within these galaxies
- Study provides valuable insights into understanding the relationship between star formation rate and radio synchrotron luminosity across different redshifts

## Summary

In this study, conducted by Timothy Garn, David A. Green, Julia M. Riley, and Paul Alexander, the authors investigate the relationship between star formation rate (SFR) and radio synchrotron luminosity in galaxies at redshifts between 0 and 2. The aim is to examine the assumptions involved in calculating the star formation history of the Universe using deep radio observations. The researchers present new observations from the Giant Metrewave Radio Telescope (GMRT) at a frequency of 610 MHz in the European Large-Area ISO Survey (ELAIS)-N2 field. They combine this data with previous GMRT surveys conducted in the ELAIS-N1 and Lockman Hole regions to create a sample of galaxies with available redshift and SFR information from the Spitzer Wide-area Infrared Extragalactic survey (SWIRE). The team tests whether the local relationship between SFR and radio luminosity can be applied to galaxies at a redshift of 2. They also investigate any evolution in this relationship with both redshift and SFR to determine if the physical processes leading to synchrotron radiation have remained consistent since the peak of star formation in the Universe. The results show that the local calibration between radio luminosity and star formation can be successfully applied to high-redshift, high-SFR galaxies selected through radio observations. However, there are a few sources where this calibration may not hold true. These sources exhibit evidence of inaccurate estimations of their SFR, possibly due to physical effects such as recent onset starburst activity or suppression of radio luminosity within these galaxies. Overall, this study provides valuable insights into understanding how star formation rate relates to radio synchrotron luminosity in galaxies across different redshifts. The findings contribute to improving our knowledge of the physical processes underlying synchrotron radiation and its connection to star formation throughout cosmic history.