Feedback in Emerging Extragalactic Star Clusters, FEAST: The Relation between 3.3 μm Polycyclic Aromatic Hydrocarbon Emission and Star Formation Rate Traced by Ionized Gas in NGC 628

Abstract We present maps of ionized gas (traced by Pa α and Br α ) and 3.3 μ m polycyclic aromatic hydrocarbon (PAH) emission in the nearby spiral galaxy NGC 628, derived from new JWST/NIRCam data from the Feedback in Emerging extrAgalactic Star clusTers (FEAST) survey. With this data, we investigate and calibrate the relation between 3.3 μ m PAH emission and star formation rate (SFR) in and around emerging young star clusters (eYSCs) on a scale of ∼40 pc. We find a tight (correlation coefficient ρ ∼ 0.9) sublinear (power-law exponent α ∼ 0.75) relation between the 3.3 μ m PAH luminosity surface density and SFR traced by Br α for compact, cospatial (within 0.″16 or ∼7 pc) peaks in Pa α , Br α , and 3.3 μ m (eYSC–I). The scatter in the relationship does not correlate well with variations in local interstellar medium metallicity, due to a radial metallicity gradient, but rather is likely due to stochastic sampling of the stellar initial mass function (IMF) and variations in the PAH heating and age of our sources. The deviation from a linear relation may be explained by PAH destruction in more intense ionizing environments, variations in age, and IMF stochasticity at intermediate to low luminosities. We test our results with various continuum subtraction techniques using combinations of NIRCam bands and find that they remain robust with only minor differences in the derived slope and intercept. An unexpected discrepancy is identified between the relations of hydrogen recombination lines (Pa α versus Br α ; H α versus Br α ).

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Publication Details

Journal
The Astrophysical Journal
Published
2024-08-01
DOI
https://doi.org/10.3847/1538-4357/ad54b4
Citations
18
Primary Topic
Astrophysics and Star Formation Studies
Type
article
Field-Weighted Citation Impact
5.97

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article

Feedback in Emerging Extragalactic Star Clusters, FEAST: The Relation between 3.3 μm Polycyclic Aromatic Hydrocarbon Emission and Star Formation Rate Traced by Ionized Gas in NGC 628

Daniela Calzetti, Varun Bajaj, Elena Sabbi, Robert Gutermuth et al.
18 citations
The Astrophysical Journal
Astrophysics and Star Formation Studies
5.97
article

Feedback in Emerging Extragalactic Star Clusters, FEAST: The Relation between 3.3 μm Polycyclic Aromatic Hydrocarbon Emission and Star Formation Rate Traced by Ionized Gas in NGC 628

Daniela Calzetti, Varun Bajaj, Elena Sabbi, Robert Gutermuth, Mark R. Krumholz, Matteo Correnti, Kelsey E. Johnson, J. E. Ryon, Benjamin Gregg, Matteo Messa, Göran Östlin, M. Cignoni, Angela Adamo, Kathryn Grasha, Alex Pedrini, Arjan Bik, J. S. Gallagher, L. J. Smith, Subhransu Maji, Sean T. Linden, M. Tosi, Ralf Kotulla, Gustavo Pérez, Jens Melinder, Helena Faustino Vieira, Giacomo Bortolini
article en
18 citations

Abstract

Abstract We present maps of ionized gas (traced by Pa α and Br α ) and 3.3 μ m polycyclic aromatic hydrocarbon (PAH) emission in the nearby spiral galaxy NGC 628, derived from new JWST/NIRCam data from the Feedback in Emerging extrAgalactic Star clusTers (FEAST) survey. With this data, we investigate and calibrate the relation between 3.3 μ m PAH emission and star formation rate (SFR) in and around emerging young star clusters (eYSCs) on a scale of ∼40 pc. We find a tight (correlation coefficient ρ ∼ 0.9) sublinear (power-law exponent α ∼ 0.75) relation between the 3.3 μ m PAH luminosity surface density and SFR traced by Br α for compact, cospatial (within 0.″16 or ∼7 pc) peaks in Pa α , Br α , and 3.3 μ m (eYSC–I). The scatter in the relationship does not correlate well with variations in local interstellar medium metallicity, due to a radial metallicity gradient, but rather is likely due to stochastic sampling of the stellar initial mass function (IMF) and variations in the PAH heating and age of our sources. The deviation from a linear relation may be explained by PAH destruction in more intense ionizing environments, variations in age, and IMF stochasticity at intermediate to low luminosities. We test our results with various continuum subtraction techniques using combinations of NIRCam bands and find that they remain robust with only minor differences in the derived slope and intercept. An unexpected discrepancy is identified between the relations of hydrogen recombination lines (Pa α versus Br α ; H α versus Br α ).

The Astrophysical JournalVol. 971(1)
University of Pisa (IT), Australian National University (AU), Space Telescope Science Institute (US), University of Wisconsin–Madison (US), University of Arizona (US), Stockholm University (SE), University of Massachusetts Amherst (US), Astronomical Observatory of Rome (IT), Agenzia Spaziale Italiana (IT), ASTRO-3D (AU), Center for Astrophysics Harvard & Smithsonian (US), AlbaNova (SE), ARC Centre of Excellence for All-sky Astrophysics (AU), Istituto Nazionale di Fisica Nucleare, Sezione di Pisa (IT), Osservatorio di Astrofisica e Scienza dello Spazio, University of Virginia (US), Cardiff University (GB)
National Aeronautics and Space Administration, California Institute of Technology, Space Telescope Science Institute, Australian Government, Swedish National Space Agency, Jet Propulsion Laboratory
Openalex Percentile: Top 3%
Astrophysics and Star Formation Studies
5.97
DOIOpen Access PDFOpenAlex
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