The far-infrared/radio correlation and radio spectral index of galaxies in the SFR-M∗ plane up to z~2

Journal article

We study the evolution of the radio spectral index and far-infrared/radio correlation (FRC) across the star-formation rate - stellar masse (i.e. SFR-M∗) plane up to z ~ 2. We start from a stellar-mass-selected sample of galaxies with reliable SFR and redshift estimates. We then grid the SFR-M∗ plane in several redshift ranges and measure the infrared luminosity, radio luminosity, radio spectral index, and ultimately the FRC index (i.e. qFIR) of each SFR-M∗-z bin. The infrared luminosities of our SFR-M∗-z bins are estimated using their stacked far-infrared flux densities inferred from observations obtained with the Herschel Space Observatory. Their radio luminosities and radio spectral indices (i.e. α, where Sν ∝ ν-α) are estimated using their stacked 1.4 GHz and 610 MHz flux densities from the Very Large Array and Giant Metre-wave Radio Telescope, respectively. Our far-infrared and radio observations include the most widely studied blank extragalactic fields - GOODS-N, GOODS-S, ECDFS, and COSMOS - covering a total sky area of ~2.0 deg2. Using this methodology, we constrain the radio spectral index and FRC index of star-forming galaxies with M∗ > 1010 M⊙ and 0

Authors: Magnelli, B; Ivison, R; Lutz, D; Valtchanov, I; Farrah, D

• Publisher: EDP Sciences
• Journal: Astronomy and Astrophysics
• Volume: 573
• Publication date: 2014-12-15
• DOI: 10.1051/0004-6361/201424937
• EISSN: 1432-0746
• ISSN: 0004-6361
• Language: English
• Keywords: Galaxies: formation; Galaxies: evolution; Infrared: galaxies; Galaxies: high-redshift; Galaxies: starburst