ESTIMATING THE STAR FORMATION RATE AT 1 kpc SCALES IN NEARBY GALAXIES
- National Radio Astronomy Observtory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)
- Theoretische Astrophysik, Albert-Ueberle-Str. 2, 69120, Heidelberg (Germany)
- Laboratoire d'Astrophysique de Marseille, Universite de Provence, CNRS (UMR6110), 38 rue Frederic Joliot Curie, 13388 Marseille Cedex 13 (France)
- Department of Astronomy, University of Maryland, College Park, MD (United States)
- Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom)
- Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
- Max Planck Institute fuer Astronomie, Koenigstuhl 17, 69117, Heidelberg (Germany)
Using combinations of H{alpha}, ultraviolet (UV), and infrared (IR) emission, we estimate the star formation rate (SFR) surface density, {Sigma}{sub SFR}, at 1 kpc resolution for 30 disk galaxies that are targets of the IRAM HERACLES CO survey. We present a new physically motivated IR spectral-energy-distribution-based approach to account for possible contributions to 24 {mu}m emission not associated with recent star formation. Considering a variety of 'reference' SFRs from the literature, we revisit the calibration of the 24 {mu}m term in hybrid (UV+IR or H{alpha}+IR) tracers. We show that the overall calibration of this term remains uncertain at the factor of two level because of the lack of wide-field, robust reference SFR estimates. Within this uncertainty, published calibrations represent a reasonable starting point for 1 kpc-wide areas of star-forming disk galaxies, but we re-derive and refine the calibration of the IR term in these tracers to match our resolution and approach to 24 {mu}m emission. We compare a large suite of {Sigma}{sub SFR} estimates and find that above {Sigma}{sub SFR} {approx} 10{sup -3} M{sub Sun} yr{sup -1} kpc{sup -2} the systematic differences among tracers are less than a factor of two across two orders of magnitude dynamic range. We caution that methodology and data both become serious issues below this level. We note from simple model considerations that when focusing on a part of a galaxy dominated by a single stellar population, the intrinsic uncertainty in H{alpha}- and FUV-based SFRs is {approx}0.3 and {approx}0.5 dex.
- OSTI ID:
- 22034434
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 144, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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