The Radio Spectral Energy Distribution and Star Formation Calibration in MIGHTEE-COSMOS Highly Star-Forming Galaxies at 1.5 < z < 3.5

Abstract

Studying the radio spectral energy distribution (SED) of distant galaxies is essential for understanding their assembly and evolution over cosmic time. We present rest-frame radio SEDs of a sample of 160 starburst galaxies at redshifts 1.5 to 3.5 in the COSMOS field, as part of the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) project. MeerKAT observations, combined with archival VLA and GMRT data, allow us to determine the integrated mid-radio (1-10 GHz) continuum (MRC) luminosity and magnetic field strength. A Bayesian method is used to model the SEDs and separate free-free and synchrotron emission. We calibrate the star formation rate (SFR) in radio both directly through SED analysis and indirectly via the infrared-radio correlation (IRRC). With a mean synchrotron spectral index of approximately 0.7, we find that the index flattens with redshift and specific SFR, suggesting that cosmic rays are more energetic in the early universe due to higher star formation activity. The magnetic field strength increases with redshift (B is proportional to (1 + z)^0.7) and with star formation rate (B is proportional to SFR^0.3), indicating a small-scale dynamo as the dominant amplification mechanism. Accounting for SED evolution, the IRRC remains redshift-invariant and does not vary with stellar mass at 1.5 < z < 3.5, though the correlation deviates from linearity. Similarly, we show that SFR estimates based on integrated MRC luminosity are also redshift-invariant.

Accepted for Publication in The Astrophysical Journal (ApJ)

References in corpus (41)

• Cosmic Star Formation History
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• The Herschel view of the dominant mode of galaxy growth from z=4 to the present day
• COSMOS2020: A panchromatic view of the Universe to $z\sim 10$ from two complementary catalogs
• Revised equipartition & minimum energy formula for magnetic field strength estimates from radio synchrotron observations
• The Cosmic Evolution Survey (COSMOS): Subaru Observations of the HST COSMOS Field
• The SCUBA-2 Cosmology Legacy Survey: 850um maps, catalogues and number counts
• The VLA-COSMOS Survey: II. Source Catalog of the Large Project
• The XMM-Newton wide-field survey in the COSMOS field. The point-like X-ray source catalogue
• Magnetism in the spiral galaxy NGC 6946: magnetic arms, depolarization rings, dynamo modes and helical fields
• The far-infrared/radio correlation and radio spectral index of galaxies in the SFR-M* plane up to z 2
• The Radio Spectral Energy Distribution and Star Formation Rate Calibration in Galaxies
• The VLA-COSMOS 3 GHz Large Project: Evolution of specific star formation rates out to $z\sim 5$
• The infrared-radio correlation of star-forming galaxies is strongly M${}_{\star }$-dependent but nearly redshift-invariant since z$\sim$4
• Exploring the infrared/radio correlation at high redshift
• High-resolution radio continuum survey of M33 II. Thermal and nonthermal emission
• The nature of the low-frequency emission of M51: First observations of a nearby galaxy with LOFAR
• The FMOS-COSMOS survey of star-forming galaxies at $z\sim 1.6$ VI: Redshift and emission-line catalog and basic properties of star-forming galaxies
• The Radio Continuum-Star Formation Rate Relation in WSRT SINGS Galaxies
• Nonlinear current helicity fluxes in turbulent dynamos and alpha quenching
• Cosmic ray transport in starburst galaxies
• A 33 GHz Survey of Local Major Mergers: Estimating the Sizes of the Energetically Dominant Regions from High Resolution Measurements of the Radio Continuum
• The non-linear infrared-radio correlation of low-z galaxies: implications for redshift evolution, a new radio SFR recipe, and how to minimize selection bias
• The Spectral Energy Distribution of Powerful Starburst Galaxies I: Modelling the Radio Continuum
• Integrated Radio Continuum Spectra of Galaxies
• The infrared-radio correlation of spheroid- and disc-dominated star-forming galaxies to z $\sim$ 1.5 in the COSMOS field
• Radio spectral properties of star-forming galaxies in the MIGHTEE-COSMOS field and their impact on the far-infrared-radio correlation
• Radio--Far infrared correlation in "blue cloud" galaxies with 0<z<1.2
• Discovery of massive star formation quenching by nonthermal effects in the center of NGC 1097
• Cosmic Star-Formation History Measured at 1.4 GHz
• An ALMA Survey of the SCUBA-2 Cosmology Legacy Survey UKIDSS/UDS Field: The Far-infrared/Radio correlation for High-redshift Dusty Star-forming Galaxies
• The VLA-COSMOS Survey: V. 324 MHz continuum observations
• Nearby galaxies in the LOFAR Two-metre Sky Survey II. The magnetic field-gas relation
• Morphology & Environment's Role on the Star Formation Rate -- Stellar Mass Relation in COSMOS from 0 < z < 3.5
• The Physical Origin of the Mass-Size Relation and Its Scatter of Disk Galaxies
• Distance and mass of the NGC 253 galaxy group
• The MOSDEF Survey: Calibrating the relationship between H$\alpha$ star-formation rate and radio continuum luminosity at $1.4<z<2.6$
• Evolution of thermal and nonthermal radio continuum emission on kpc scales--Predictions for SKA
• Reconciling the magnetic field in central disc galaxies with the dynamical mass using the cosmological simulations
• Radio-FIR correlation- A probe into cosmic ray propagation in the nearby galaxy IC 342