Generate tables of values of disc scale length for use in galaxy formation models. This program is based in the disc formation model by Mo, Mao & White (1998).

This program is written in C and has been tested with gcc version 4.2.4. To compile, just run 'make'.

To run the program:

./rdtables parameterfile

The program generates tables for selected values of redshift, halo concentration, and bulge mass fraction m_b = M_bulge / M_vir. The virial mass is defined as the mass enclosed by r_200, the radius within which the enclosed mass density is 200 times the universal critical density.

Two different sets of tables can created: rdtable_NNN_NNN stores values of disc scale length, and vctable_NNN_NNN stores the value of the circular velocity at the flat portion of the rotation curve (here identified with the circular velocity at a specified multiple of the scale radius). Both sets of data are always generated as part of the calculation, but you can turn off the generation of one or the other set of files to save time.

We have chosen to use the velocity at the flat portion of the rotation curve because bulges are modeled as point masses, and thus the maximum circular velocity is not a good choice. Another option would be to select the velocity at the optical radius, defined e.g. as the radius which encloses a given percentage of the total mass, but this also causes problems whenever the bulge mass alone is equal to or greater than the selected fraction.

Compilation options (enable in the makefile):

• TESTMODE runs a single calculation in interactive mode and exits, without generating any table files. This mode requires the user to provide a set of tables that relate halo concentration to virial mass for the selected cosmological model (generate these tables with program conctables).
• DEBUG prints extra information while running.

Each table file generated by this program is a collection of double-entry tables for a given redshift and halo concentration: table_m(i,j) is the value corresponding to row i in disc mass fraction m_d = M_disc / M_vir and column j in halo spin parameter. There are Nbulge such tables in each file, one for each of the Nbulge considered values of bulge mass fraction. The format of the files is the following:

(Redshift) (Concentration) (Bulge mass fraction[0]) (Value[0][0] Value[0][1] ... Value[0][Ncols-2] Value[0][Ncols-1] Value[1][0] Value[1][1] ... Value[1][Ncols-2] Value[1][Ncols-1] . . . Value[Nrows-1][0] Value[Nrows-1][1] ... Value[Nrows-1][Ncols-1]) (Bulge mass fraction[1]) (Value[0][0] Value[0][1] ... Value[0][Ncols-2] Value[0][Ncols-1] Value[1][0] Value[1][1] ... Value[1][Ncols-2] Value[1][Ncols-1] . . . Value[Nrows-1][0] Value[Nrows-1][1] ... Value[Nrows-1][Ncols-1]) . . .

An additional file, tables_header.dat, is created in the output directory. This file lists all the selected values of redshift, concentration, number of rows, columns and values of m_b, then label values of rows, columns and m_b.

Directory test/ contains a sample program, rdtest.c, that reads the tables generated with rdtables and interpolates to find the scale radius and circular velocity for a given set of values entered by the user. Compile it by running 'make' inside the test/ directory (it has its own makefile) and to run it type

./rdtest path_to_table_files

You can use this program as a template to include these tables in another code.

The values obtained from this test program should not differ from those obtained by running rdtables in test mode by more than 10^-3. Please email me if you find a case where the differences are higher than this.

This package is to be publicly available from me. Feel free to distribute the package as it is (unchanged). Please do not pass modified versions to others, as the resulting variants may cause errors that I can no longer sort out. Instead of modifying yourself, suggest the modification to me (if it is a good idea, others can then use it as well). It is presumably always a good idea to ask me for another copy before distributing one yourself, since in the meantime I might well have updated the package to a new version.