- #1
SplinterIon
- 17
- 0
Just a quickie
I'm taking a slice of a galaxy picture and plotting luminosity vs kpc. I'm fitting a luminosity profile (de vacouleurs) and keeping disk scale length as a free parameter. However, textual values for this (referred to as h from now on) range between 3-4 kpc for most galaxies. h is defined as the radius when the luminosity decays to 1/e of its original value. My plots for most galaxies end up with h between 7-14 kpc.
Is there something I'm doing wrong? Am I missing something fundamental? Can I just chalk this down to smeared pictures and dust effects?
If this doesn't work - I'm going to photometrically integrate and hope for the best
BTW: This is for a science fair (for anyone wondering)
I'm taking a slice of a galaxy picture and plotting luminosity vs kpc. I'm fitting a luminosity profile (de vacouleurs) and keeping disk scale length as a free parameter. However, textual values for this (referred to as h from now on) range between 3-4 kpc for most galaxies. h is defined as the radius when the luminosity decays to 1/e of its original value. My plots for most galaxies end up with h between 7-14 kpc.
Is there something I'm doing wrong? Am I missing something fundamental? Can I just chalk this down to smeared pictures and dust effects?
If this doesn't work - I'm going to photometrically integrate and hope for the best
BTW: This is for a science fair (for anyone wondering)