Inclination Dependent Luminosity Function of Spiral Galaxies
Abstract
We present the inclination dependent luminosity function (LF) of spiral galaxies of the Sloan Digital Sky Survey (SDSS). The sample up to 61506 spiral galaxies is selected by fracdeV[r] < 0.5 from the second data release (DR2) of SDSS. The apparent axis ratio (b/a) is used as an observational inclination indicator to define subsets of spiral galaxies. Also, a Monte Carlo process is employed to connect b/a to the corrected viewing angle (cos(θ)), with the thickness (ν) and ellipticity (ɛ) of disks are all involved in the simulation. LFs of all 5 SDSS photometric wave bands (u, g, r, i, z) were drawn for different subsets defined by b/a. Significant correction is found between characteristic magnitudes (M*s) of subsets and their median values of inclinations, while M*s are almost linearly reduced with log(cos(θ)) from edge-on to face-on galaxies, which could be fairly attributed to the dust extinction of spiral galaxies. A linear fit estimates the intensity of this extinction (γ) and the expected M*s for 'pure' face-on galaxies. Then, in an improved approach of fitting for LF, γ is regard as the third fitting parameter, and the extinction corrected LF, described by M*[corr] and α[corr] is measured all together. Results taken from different methods are all well consisted each other, indicate that, after correction of the dust, the intrinsic characteristic luminous of spiral galaxies should be 0.2∼0.3 magnitudes brighter than the apparent ones in optical wave bands. Additionally, from the intensity of dust extinction of 5 SDSS wave bands, the extinction curve in optical band are found to be well described by the function of τ[λ]=? τ[V] ( λ/5500)n, with the best fitting value n=-0.96 ±?0.07 .
- Publication:
-
Galaxy Evolution across the Hubble Time
- Pub Date:
- May 2007
- DOI:
- 10.1017/S1743921306005837
- Bibcode:
- 2007IAUS..235..151S