Millisecond Pulsars Modify the Radio-SFR Correlation in Quiescent Galaxies
Abstract
The observed correlation between the far-infrared and radio luminosities of galaxies illustrates the close connection between star formation and cosmic-ray production. Intriguingly, recent gamma-ray observations indicate that recycled/millisecond pulsars (MSPs), which do not trace recent star formation, may also efficiently accelerate cosmic-ray electrons. We study the contribution of MSPs to the galactic non-thermal radio emission, finding that they can dominate the emission from massive quiescent galaxies. This model can explain recent LOFAR observations that found a peculiar radio excess in galaxies with high stellar masses and low star-formation rates. We show that MSP-based models provide a significantly improved fit to LOFAR data. We discuss the implications for the radio-FIR correlation, the observation of radio excesses in nearby galaxies, and local electron and positron observations.
Keywords
Cite
@article{arxiv.2005.08982,
title = {Millisecond Pulsars Modify the Radio-SFR Correlation in Quiescent Galaxies},
author = {Takahiro Sudoh and Tim Linden and John F. Beacom},
journal= {arXiv preprint arXiv:2005.08982},
year = {2021}
}
Comments
Main text 14 pages, 4 figures. Accepted in PRD