[IPTA-cs] Linear interpolation of Ken's data file

[Kai Schmitz <kai schmitz cern ch>]

Hi All,

Let me share a figure with you that I also just posted in our Slack 
channel. Attached to this mail, you'll find a contour plot of the 
interpolating function for h^2 \Omega that I constructed based on Ken's 
data file. This function lives in the 2D parameter space spanned by the 
GW frequency f and the cosmic-string tension Gmu. Or referring to Ken's 
data file, one could say: the contour plot in the attachment shows 
interpolated values for the quantity in the third column in Ken's file 
in dependence on the quantities in the first and second columns in Ken's 
file.

The main message from the plot is: Mathematica's "Interpolation" command 
gives us a smooth and well-behaved interpolating function -- simply a 
linear interpolation in log-log-log space -- which we can use to compute 
the GW signal in the 30 IPTA frequency bins; see the two look-up tables 
I shared on Slack.

Let me know if you have got questions on the plot, or if I can help with 
the implementation into ENTERPRISE. For instance, let me know if you 
preferred to have a look-up table in a different format.

Thanks a lot and talk to you soon.

Best regards, Kai.

PS: I posted another, global version of the plot on Slack, which shows 
the function across the entire range of f and Gmu values in Ken's file. 
It's not attached to this email because of size restrictions.

Attachment: interpolation_local.png
Description: PNG image