Quantification of the Age Dependence of Mid-infrared Star Formation Rate Indicators
Abstract We combine James Webb Space Telescope images of the nearby galaxy NGC 5194 in the hydrogen recombination line Pa α (1.8756 μ m) from the Cycle 1 program JWST-FEAST with 21 μ m dust continuum images from the Cycle 2 Treasury program JWGT to quantify the difference in the calibration of mid-infrared star formation rates (SFRs) between H II regions and galaxies. We use archival Hubble Space Telescope H α imaging to correct the Pa α emission for the effects of dust attenuation. Our data confirm previous results that the dust-corrected Pa α flux is tightly correlated with the 21 μ m emission at the scales of H II regions. When combined with published JWST data for the H II regions of the galaxy NGC 628 and Spitzer Space Telescope 24 μ m data for whole galaxies and for kiloparsec-size galaxy regions, we show that the L (24)– L (Pa α ) relation has exponent > 1 across six decades in luminosity. In addition, the hybrid 24 μ m + H α SFR indicator has a scaling constant about 4.4 times higher for H II regions than for whole galaxies, also in agreement with previous results. Models of stellar populations with a range of star formation histories reveal that the observed trends can be entirely ascribed to and quantified with the contribution to the infrared emission by stellar populations older than ∼5–6 Myr. Based on the models’ results, we provide (1) a calibration for the infrared SFR across 6 orders of magnitude in L (24), from H II regions to luminous galaxies, and (2) a prescription for the scaling constant of the hybrid infrared SFR indicators as a function of the star formation timescale.
Authors
- L. K. Hunt (ORCID: https://orcid.org/0000-0001-9162-2371)
- Karin M. Sandstrom (ORCID: https://orcid.org/0000-0002-4378-8534)
- Daniela Calzetti (ORCID: https://orcid.org/0000-0002-5189-8004)
- Thomas S. -Y. Lai (ORCID: https://orcid.org/0000-0001-8490-6632)
- Varun Bajaj (ORCID: https://orcid.org/0009-0008-4009-3391)
- Elena Sabbi (ORCID: https://orcid.org/0000-0003-2954-7643)
- Fabian Walter (ORCID: https://orcid.org/0000-0003-4793-7880)
- Ilse De Looze (ORCID: https://orcid.org/0000-0001-9419-6355)
- Martha L. Boyer (ORCID: https://orcid.org/0000-0003-4850-9589)
- M. Relaño (ORCID: https://orcid.org/0000-0003-1682-1148)
- Mark R. Krumholz (ORCID: https://orcid.org/0000-0003-3893-854X)
- Matteo Correnti (ORCID: https://orcid.org/0000-0001-6464-3257)
- Kelsey E. Johnson (ORCID: https://orcid.org/0000-0001-8348-2671)
- B. T. Draine (ORCID: https://orcid.org/0000-0002-0846-936X)
- Benjamin Gregg (ORCID: https://orcid.org/0000-0003-4910-8939)
- Matteo Messa (ORCID: https://orcid.org/0000-0003-1427-2456)
- Bruce G. Elmegreen (ORCID: https://orcid.org/0000-0002-1723-6330)
- A. Duarte-Cabral (ORCID: https://orcid.org/0000-0002-5259-4774)
- Göran Östlin (ORCID: https://orcid.org/0000-0002-3005-1349)
- Angela Adamo (ORCID: https://orcid.org/0000-0002-8192-8091)
- Tony D. Weinbeck (ORCID: https://orcid.org/0009-0005-8923-558X)
- Kathryn Grasha (ORCID: https://orcid.org/0000-0002-3247-5321)
- Torsten Boeker (ORCID: https://orcid.org/0000-0002-5666-7782)
- Alex Pedrini (ORCID: https://orcid.org/0000-0002-8222-8986)
- Eva Schinnerer (ORCID: https://orcid.org/0000-0002-3933-7677)
- J. S. Gallagher (ORCID: https://orcid.org/0000-0001-8608-0408)
- L. J. Smith (ORCID: https://orcid.org/0000-0002-0806-168X)
- Sean T. Linden (ORCID: https://orcid.org/0000-0002-1000-6081)
- Ralf S. Klessen (ORCID: https://orcid.org/0000-0002-0560-3172)
- M. Tosi (ORCID: https://orcid.org/0000-0002-0986-4759)
- Evan D. Skillman (ORCID: https://orcid.org/0000-0003-0605-8732)
- Robert C. Kennicutt (ORCID: https://orcid.org/0000-0001-5448-1821)
- Daniel A. Dale (ORCID: https://orcid.org/0000-0002-5782-9093)
- Helena Faustino Vieira (ORCID: https://orcid.org/0000-0002-2199-0977)
- Giacomo Bortolini (ORCID: https://orcid.org/0009-0003-6182-8928)
- Drew Lapeer (ORCID: https://orcid.org/0009-0009-5509-4706)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-09-29
- DOI
- https://doi.org/10.3847/1538-4357/adfbe0
- Citations
- 1
- Primary Topic
- Stellar, planetary, and galactic studies
- Type
- article
- Field-Weighted Citation Impact
- 1.15