2010/01/08 by Ching-Wa Yip, Alex S. Szalay, Alex Szalay +7 · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Balmer series #Extinction (optical mineralogy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #RADIUS #Redshift #Spectral line #Stars #Thick disk #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/709/2/780
published as 2010 ApJ 709 780 · To appear in the Astrophysical Journal
openalex publication_date 2010/01/08 · arxiv created 2010/01/09 · arxiv updated 2015/05/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Extinction in galaxies affects their observed properties. In scenarios describing the distribution of dust and stars in individual disk galaxies, the amplitude of the extinction can be modulated by the inclination of the galaxies. In this work, we investigate the inclination dependency in composite spectra of star-forming disk galaxies from the Sloan Digital Sky Survey Data Release 5. In a volume-limited sample within a redshift range 0.065–0.075 and a r -band Petrosian absolute magnitude range −19.5 to −22 mag which exhibits a flat distribution of inclination, the inclined relative to face-on extinction in the stellar continuum is found empirically to increase with inclination in the g , r , and i bands. Within the central 0.5 intrinsic half-light radius of the galaxies, the g -band relative extinction in the stellar continuum for the highly inclined objects (axis ratio b / a = 0.1) is 1.2 mag, agreeing with previous studies. The extinction curve of the disk galaxies is given in the rest-frame wavelengths 3700–8000 Å, identified with major optical emission and absorption lines in diagnostics. The Balmer decrement, Hα/Hβ, remains constant with inclination, suggesting a different kind of dust configuration and/or reddening mechanism in the H ii region from that in the stellar continuum. One factor is shown to be the presence of spatially non-uniform interstellar extinction, presumably caused by clumped dust in the vicinity of the H ii region.