The Resolved Star Formation Law in NGC 7469 from JWST, ALMA, and VLA

Abstract

We investigate the star formation process within the central 3.3 kpc region of the nearby luminous infrared Seyfert NGC 7469, probing scales ranging from 88 to 330 pc. We combine JWST/MIRI imaging with the F770W filter, with CO(2 – 1) and the underlying 1.3 mm dust continuum data from the Atacama Large Millimeter/submillimeter Array, along with Karl G. Jansky Very Large Array radio continuum observations at 22 GHz. NGC 7469 hosts a starburst ring which dominates the overall star formation activity. We estimate the global star formation rate (SFR) ∼ 11.5 M _⊙ yr ^−1 from the radio at 22 GHz, and a cold molecular gas mass M (H _2 ) ∼ 6.4 × 10 ^9 M _☉ from the CO(2 – 1) emission. We find that the 1.3 mm map shows a morphology remarkably similar to those traced by the 22 GHz and the 7.7 μ m polycyclic aromatic hydrocarbon (PAH) emission observed with JWST. The three tracers reproduce the morphology of the starburst ring with good agreement. We further investigate the correlations between the PAHs, the SFR, and the cold molecular gas. We find a stronger correlation of the PAHs with star formation than with CO, with steeper correlations within the starburst ring ( n > 2) than in the outer region ( n < 1). We derive a correlation between the SFR and the cold molecular gas mass surface densities, the Kennicutt–Schmidt (K-S) star formation law. Comparisons with other galaxy populations, including starburst galaxies and active galactic nuclei, highlighted that NGC 7469 exhibits an intermediate behavior to the K-S relations found for these galaxy populations.

Keywords

• AGN host galaxies
• Molecular gas
• Star formation
• Interstellar medium