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arXiv · 1203.0001

The JCMT Nearby Galaxies Legacy Survey VII: H\alpha{} imaging and massive star formation properties

J. R. Sánchez-Gallego·J. H. Knapen·C. D. Wilson·P. Barmby·M. Azimlu·S. Courteau
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Abstract

We present H\alpha{} fluxes, star formation rates (SFRs) and equivalent widths (EWs) for a sample of 156 nearby galaxies observed in the 12CO J=3-2 line as part of the James Clerk Maxwell Telescope Nearby Galaxies Legacy Survey. These are derived from images and values in the literature and from new H\alpha{} images for 72 galaxies which we publish here. We describe the sample, observations and procedures to extract the H\alpha{} fluxes and related quantities. We discuss the SFR properties of our sample and confirm the well-known correlation with galaxy luminosity, albeit with high dispersion. Our SFRs range from 0.1 to 11 Msun yr-1 with a median SFR value for the complete sample of 0.2 Msun yr-1. This median values is somewhat lower than similar published measurements, which we attribute, in part, to our sample being HI-selected and, thus, not biased towards high SFRs as has frequently been the case in previous studies. Additionally, we calculate internal absorptions for the H\alpha{} line, A(H\alpha{}), which are lower than many of those used in previous studies. Our derived EWs, which range from 1 to 880\AA{} with a median value of 27\AA{}, show little dependence with luminosity but rise by a factor of five from early- to late-type galaxies. This paper is the first in a series aimed at comparing SFRs obtained from H\alpha{} imaging of galaxies with information derived from other tracers of star formation and atomic and molecular gas.

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J. R. Sánchez-Gallego, J. H. Knapen, C. D. Wilson, P. Barmby, M. Azimlu, S. Courteau. 2012-02-29. The JCMT Nearby Galaxies Legacy Survey VII: H\alpha{} imaging and massive star formation properties. https://doi.org/10.1111/j.1365-2966.2012.20845.x

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