Computing visibilities¶

We need to have the field of view of the system, a list of projected baseline lengths in meters and the position angles in degrees (baseline.in). The second value is the number of baselines:

dx(")     dy(") (Field of view)
 0.2     0.2
14
 Baseline(m) P.A. (deg) N.B. projected baseline, North=0 deg
   0.0         45.0
    1e-2        45.0
    0.1         45.0
    1.0         10.0
    5.0         5.0
   10.0         25.
   20.0         30.
   50.0         35.
   80.0         60.0
   100.0        12.0
   130.0        0.0
   150.0        0.0
   200.0        0.0
   500.0        0.0

This example file is given in /input_examples/visibilities_calculations/baseline.in

ProDiMo will compute the visibilities if

.true.      ! calcSED            : calculate SED and images?
.true.      ! monoSED            : use monochromatic mode?
150         ! NlamSED            : number of lambda gridpoints
0.1         ! lminSED            : minimum lambda[mic]
10000.0     ! lmaxSED            : minimum lambda[mic]
56.0        ! dist      [pc]     : distance
7.0         ! incl      [deg]    : inclination (0=face-on)
.true.      ! compute_visibilities : compute interferometric visibilities for the baselines in baseline.in

ProDiMo writes the visilities in a file called visibilities.out:

8/4/2016: from revision 89b04430 the phase will be also provided in the last column

   48.0000000000000       inclination[degree]
         150  Nlam
          14  Nbaselines
  0.200000000000000       0.200000000000000
  Field of view (arcsec x arcsec)=
 baseline[m] P.A.[deg]  lam[mic]     nu[Hz]      real(FT(Fnu))       imag(FT(Fnu))          V2            Fnu_fov[Jy]        FStar[Jy]
0.00E+00      0.00     0.100000000 2.998E+15      7.299239E-23      0.000000E+00      1.000000E+00      7.299239E+00      5.792409E+00
1.00E-02      0.00     0.100000000 2.998E+15      7.289455E-23     -6.537409E-26      9.973217E-01      7.299239E+00      5.792409E+00
1.00E-01      0.00     0.100000000 2.998E+15      6.900801E-23     -6.057172E-25      8.938759E-01      7.299239E+00      5.792409E+00
1.00E+00      0.00     0.100000000 2.998E+15      5.702300E-23     -4.771483E-26      6.103026E-01      7.299239E+00      5.792409E+00
5.00E+00      0.00     0.100000000 2.998E+15      5.771899E-23     -3.141954E-27      6.252911E-01      7.299239E+00      5.792409E+00
...

The complex visibilities as well as the V2 values are computed for all the frequencies used in the monochromatic SED mode calculation.