ASTRO 735 - Problems

Set 4

Due: Mon., Dec 04, in class

1. Galaxy Counts - a simple model

Calculate the following quantities for the K band (A0V zeropoint):

A(m) for m = 10 to 28 mag (plot)
m as a function of redshift for an M* galaxy (plot - log scale please)
Mean M in each bin of m (plot)

In addition to providing me with plots, also email me your data files, clearly identified, with clearly identified columns.

Assume:

(i) phi(M) with typical values for the parameters for the Schecter function approximating the total field galaxy luminosity function (LF; integrated over all types) in the B band (A0V zeropoint):

M^* = -21.0 + 5 log h
phi^* = 1.5 x 10^-2 h³ mag^-1 Mpc^-3
alpha = -1.3

where as usual

h = H₀ / 100 km s^-1 Mpc^-1.

(ii) B-K=4 in the rest-frame for all galaxies.

(iii) K-corrections specified by spectral energy distribution f_nu proportional to nu^-beta with beta = 0.5.

(iv) The luminosity function, phi(M) is non-evolving.

(v) The galaxy spectral energy distributions are non-evolving.

(vi) The galaxy spatial distribution is homogeneous.

(vii) The curvature is specified by Omega₀=0.3 and Omega_lambda=0.7.

(viii) The observer is able to detect all sources down to the apparent magnitude limits.

last update: Nov 20, 2000

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