2011/10/04 by Ching-Wa Yip, Alex S. Szalay, Yip, Ching-Wa +1
Physics and Astronomy · #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #astro-ph.CO
paper · pdf · doi:10.48550/arxiv.1110.0726
2 tables, 3 figures. Submitted to ApJ Letter
arxiv created 2011/10/04 · arxiv updated 2011/10/05
Star formation is one of the most important processes in galaxy formation. The luminosity of Halpha recombination and [OII] forbidden emissions remain to be most used in measuring formation rate of massive stars in galaxies. Here we report the inclination dependency of continuum-subtracted and aperture-corrected nebular luminosities, including Halpha, Hbeta, Hgamma, [OII], [NII], of disk-dominated galaxies in the local universe. Their luminosities decrease by a factor of three from face-on to edge-on (axis ratio limit = 0.17) orientations. This dependence is deduced to be caused by extinction due to diffuse dust within the disks with an amplitude of 1.2 mag. The line-luminosity--inclination relation provides a novel way to remove extinction in emission lines and present star formation rate of disk galaxies out to redshift of 1.6.