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Full-Text Articles in Physical Sciences and Mathematics

Dust-Corrected Star Formation Rates Of Galaxies. I. Combinations Of H Alpha And Infrared Tracers, Rc Kennicutt, Cn Hao, D Calzetti, J Moustakas, Da Dale, G Bendo, Cw Engelbracht, Bd Johnson, Jc Lee Jan 2009

Dust-Corrected Star Formation Rates Of Galaxies. I. Combinations Of H Alpha And Infrared Tracers, Rc Kennicutt, Cn Hao, D Calzetti, J Moustakas, Da Dale, G Bendo, Cw Engelbracht, Bd Johnson, Jc Lee

Astronomy Department Faculty Publication Series

We combine Hα emission-line and infrared (IR) continuum measurements of two samples of nearby galaxies to derive dust attenuation-corrected star formation rates (SFRs). We use a simple energy balance based method that has been applied previously to H II regions in the Spitzer Infrared Nearby Galaxies Survey, and extend the methodology to integrated measurements of galaxies. We find that our composite Hα + IR based SFRs are in excellent agreement with attenuation-corrected SFRs derived from integrated spectrophotometry, over the full range of SFRs (0.01-80 M sun yr-1) and attenuations (0-2.5 mag) studied. We find that the combination of Hα and …


The Three-Dimensional Dynamic Structure Of The Inner Orion Nebula, C. R. O'Dell, W. J. Henney, N. P. Abel, Gary J. Ferland, S. J. Arthur Jan 2009

The Three-Dimensional Dynamic Structure Of The Inner Orion Nebula, C. R. O'Dell, W. J. Henney, N. P. Abel, Gary J. Ferland, S. J. Arthur

Physics and Astronomy Faculty Publications

The three-dimensional structure of the brightest part of the Orion Nebula is assessed in the light of published and newly established data. We find that the widely accepted model of a concave blister of ionized material needs to be altered in the southwest direction from the Trapezium, where we find that the Orion-S feature is a separate cloud of very optically thick molecules within the body of ionized gas, which is probably the location of the multiple embedded sources that produce the optical and molecular outflows that define the Orion-S star formation region. Evidence for this cloud comes from the …


Comparison Of H Alpha And Uv Star Formation Rates In The Local Volume: Systematic Discrepancies For Dwarf Galaxies, Jc Lee, Ag De Paz, C Tremonti, Rc Kennicutt, S Salim, M Bothwell, D Calzetti, J Dalcanton, D Dale, C Engelbracht, Sjjg Funes, B Johnson, S Sakai, E Skillman, L Van Zee, F Walter, D Weisz Jan 2009

Comparison Of H Alpha And Uv Star Formation Rates In The Local Volume: Systematic Discrepancies For Dwarf Galaxies, Jc Lee, Ag De Paz, C Tremonti, Rc Kennicutt, S Salim, M Bothwell, D Calzetti, J Dalcanton, D Dale, C Engelbracht, Sjjg Funes, B Johnson, S Sakai, E Skillman, L Van Zee, F Walter, D Weisz

Astronomy Department Faculty Publication Series

Using a complete sample of ~300 star-forming galaxies within 11 Mpc of the Milky Way, we evaluate the consistency between star formation rates (SFRs) inferred from the far ultraviolet (FUV) non-ionizing continuum and Hα nebular emission, assuming standard conversion recipes in which the SFR scales linearly with luminosity at a given wavelength. Our analysis probes SFRs over 5 orders of magnitude, down to ultra-low activities on the order of ~10-4 M sun yr-1. The data are drawn from the 11 Mpc Hα and Ultraviolet Galaxy Survey (11HUGS), which has obtained Hα fluxes from ground-based narrowband imaging, and UV fluxes from …