I solved it -- of course the easiest thing to do turned out to be converting the mag/arcsec^2 values into real luminosity density = L_sun/pc^2, then fitting the result and translating the fitted curve back into mag/arcsec^2 units.
Sort of awkward, but it seems to have worked without losing...
Hi everybody, I have a very quick question about surface brightness profiles for an edge-on galactic disk.
I have surface brightness values (V-band, not that it matters) in units of mag/arcsec^2 as usual, as a function of z, which is the distance from the galactic disk's plane. I'd like to...
So obviously if Widrow et al. have V = 100 km/s and L = 1 kpc, then the time unit is T = 3.09e19/1e5 = 3.09e14 seconds = 9.78 Myr.
Then that gives us GM/V^2 = (6.67e-11 * 4.6e39) / (1e5)^2 = 3e19 meters =1 kpc, if we are given our mass unit first, and rearranging solves for the mass unit if...
I should have better said: my set units are velocity and length (100 km/s and 1 kpc, respectively), as drawn from Widrow et al. 2003's disk/bulge/halo models for M31 (see note A on pg.22 here). The authors state that setting G=1 implies a mass unit of 2.3e9 M_sol (though there is an unfortunate...
Hey everyone,
I'm knocking my head against something and for some reason I can't get it to work out -- I'm running an N-body simulation which uses an internal gravitational constant of 1, meaning that the timestep used is a function of the units of mass, length, and velocity.
But I don't know...