Inputs

When running PTArcade, the user can provide two input files:

• Model file · Required – This file, passed via the -m input flag, contains the definition of the new-physics signal. In the case of stochastic signals, this boils down to defining the GWB energy density per logarithmic frequency interval, \(d\rho_{\textrm{GW}}/d\ln f\), as a fraction of the closure density:

  \[ h^2\Omega_{\textrm{GW}}(f;\,\vec{\theta}) \equiv \frac{h^2}{\rho_c}\frac{d\rho_{\textrm{GW}}(f;\,\vec{\theta})}{d\ln f}\,, \]

  where \(\vec{\theta}\) is the set of new-physics parameters describing the signals. In case of deterministic signals, the user should define the time series of induced timing delays, \(s(t;\,\vec{\theta})\), in units of seconds.

• Configuration file · Optional – In addition to the model file, the user can also pass a configuration file via the input flag -c. The configuration file is a simple Python file that allows the user to adjust several parameters of the run.

In the following, we will discuss the details of both these input files.