This page contains the input specification reference for gateau. Each element in gateau is set using a Python dictionary. Here, for each dictionary, we supply a table containing the string representation of the field, the symbol we use in the user guide to denote the quantity (if applicable), a description of what the field symbolises, the allowed datatypes and shapes/sizes, any potential default values, allowed ranges, and the required physical units. If a parameter has a default value, it automatically implies that parameter is optional. Note also that the allowed range only specifies the range in which the simulation will not produce errors. Deciding if the output makes sense is still also for the user to decide and verify.

Source Dictionary

Name of field	Symbol	Description	Datatype	Default value	Allowed range	Units
"az_src"	\(\phi\)	Azimuth values of source cube	1D array of size \(N_\phi\)	-	[0,360]	\(^\circ\)
"el_src"	\(\theta\)	Elevation values of source cube	1D array of size \(N_\theta\)	-	(0,90]	\(^\circ\)
"f_src"	\(\nu\)	Frequencies of source cube	1D array of size \(N_\nu\)	-	[ \(7\cdot10^{11},9\cdot10^{12}\)]	Hz
"I_nu"	\(I_\nu\)	Source specific intensity cube	3D array of shape \(N_\phi\times N_\theta\times N_\nu\)	-	\(\mathbb{R}_{\geq 0}\)	W \(\:\)m \(^{-2}\) sr \(^{-1}\) Hz \(^{-1}\)

Atmosphere Dictionary

Name of field	Symbol	Description	Datatype	Default value	Allowed range	Units
"path"	-	Path to folder containing prepared ARIS files	string	-	-	-
"dx"	\(\Delta x\)	Size of pixel in atmosphere screen along \(x\)-axis	float	0.2	\(\mathbb{R}^+\)	m
"dy"	\(\Delta y\)	Size of pixel in atmosphere screen along \(y\)-axis	float	0.2	\(\mathbb{R}^+\)	m
"h_column"	\(h_\mathrm{column}\)	Height of atmospheric column above telescope	float	1500	\(\mathbb{R}^+\)	m
"v_wind"	\(u_\mathrm{w}\)	Windspeed along azimuth direction	float	10	\(\mathbb{R}_{\geq 0}\)	m s \(^{-1}\)
"PWV0"	PWV \(_0\)	Average PWV around which fluctuations are added. If a linear gradient throughout the observation is desired, supply a 2-tuple (PWV \(_\mathrm{start}\), PWV \(_\mathrm{end}\)) and `gateau` will interpolate between these two values	float, 2-tuple	1	[0.1,5.5]	mm
"T_atm"	\(T_\mathrm{atm}\)	Physical temperature of atmosphere	float	273	\(\mathbb{R}^+\)	K

Telescope Dictionary

Name of field	Symbol	Description	Datatype	Default value	Allowed range	Units
"eta_taper"	\(\eta_\mathrm{t}\)	Taper efficiency of primary aperture of telescope. If \(\eta_\mathrm{t}\) is an array defined on some frequencies \(\nu_\eta\), this field should be filled with a 2-tuple \((\eta_\mathrm{t}, \nu_\eta)\)	float, 2-tuple	-	[0,1]	-
"s_rms"	\(\rho_\mathrm{surf}\)	Root-mean square surface roughness	float	0	\(\mathbb{R}^+\)	\(\mu\)m

Instrument Dictionary

Name of field	Symbol	Description	Datatype	Default value	Allowed range	Units
"fmin_ch"	\(f_\mathrm{min}\)	Lowest channel frequency	float	-	[ \(7\cdot10^{11},9\cdot10^{12}\)]	Hz
"fmax_ch"	\(f_\mathrm{max}\)	Highest channel frequency	float	-	[ \(7\cdot10^{11},9\cdot10^{12}\)]	Hz
"nf_ch"	\(N_f\)	Number of channel frequencies	int	-	\(\mathbb{Z}^+\)	Hz
"R"	\(R\)	Resolving power of individual filter. If an array, the "f_ch" field must also be supplied and must have the same size.	float, 1D array of size \(N_f\)	-	\(\mathbb{R}^+\)	-
"f_ch"	\(f\)	Array of channel frequencies. Only supply if you do not want `gateau` to calculate these for you. Filling this field will completely override the "fmin_ch", "fmax_ch", and "nf_ch" fields.	1D array	-	[ \(7\cdot10^{11},9\cdot10^{12}\)]	Hz
"f_sample"	\(f_\mathrm{sample}\)	Sampling frequency of readout	float	-	\(\mathbb{R}^+\)	Hz
"eta_peak"	\(\eta_\mathrm{peak}\)	Peak height of filter in isolation	float, 1D array of size \(N_f\)	1	[0,1]	-
"use_filterbank"	-	Whether to use the filterbank model or independent Lorentzians, in case `gateau` should generate the transmission curves.	bool	True	{True, False}	-
"transmission"	\(\eta_\mathrm{trans}\)	Matrix with transmission curves. If `gateau` should create the transmission curves, do not fill this field. If you want to supply your own transmission curves, pass them to this field. In this case, it is mandatory that "f_ch" is passed as well.	2D array, axis 0 must have same size as \(f\)	-	[0,1]	-
"pink_alpha"	\(\alpha\)	Slope of pink noise power spectral density	float, 1D array of size \(N_f\)	0	\(\mathbb{R}_{\geq 0}\)	-
"pink_level"	\(A\)	Level of pink noise	float, 1D array of size \(N_f\)	0	\(\mathbb{R}_{\geq 0}\)	-
"radius"	\(R_\mathrm{hex}\)	Circumradius of hexagonal spaxel configuration, excluding central spaxel	int	0	\(\mathbb{Z}_{\geq 0}\)	# of spaxels
"spacing"	\(\delta_\mathrm{hex}\)	Far-field pointing separation between spaxels along the circumradius	float	0	\(\mathbb{R}_{\geq 0}\)	\(^\circ\)
"pointings"	-	Spaxel pointing offsets with respect to telescope broadside. If this field is supplied, the "radius" and "spacing" fields will be ignored. The pointing offsets must be supplied with a 2-tuple \((\Delta\phi,\Delta\theta)\), containing the azimuth and elevation offset arrays for each spaxel.	2-tuple	-	[0,360] \((\Delta\phi)\), (0,90) \((\Delta\theta)\)	\(^\circ\)

Cascade Stage Dictionaries

For the cascade, there are two dictionary types. The reflective stage is described by:

Name of field	Symbol	Description	Datatype	Default value	Allowed range	Units
"eta_coup"	\(\eta_k\)	Fraction of spectral power entering stage \(k\) and transmitted to next stage \(k+1\). If a string, needs to be "Ohmic-Al" to choose Ohmic losses. If \(\eta_k\) is an array defined on some frequencies \(\nu_\eta\), this field should be filled with a 2-tuple \((\eta_k, \nu_\eta)\)	float, string, 2-tuple	-	[0,1]	-
"T_parasitic"	\(T_k\)	Temperature coupling parasitically to instrument at stage \(k\). If set to the string "atmosphere", `gateau` will let the stage couple to the atmosphere sky signal, without source	float, string	-	\(\mathbb{R}^+\)	K

A refractive stage is defined by the following:

Name of field	Symbol	Description	Datatype	Default value	Allowed range	Units
"thickness"	\(d\)	Thickness of material	float	-	\(\mathbb{R}^+\)	m
"neff"	\(n\)	Effective refractive index of material	float	-	\(\mathbb{R}^+\)	-
"tandelta"	\(\tan \delta\)	Loss tangent of material	float	-	\(\mathbb{R}^+\)	-
"T_parasitic_refl"	-	Temperature of surroundings seen in reflection	float	-	\(\mathbb{R}^+\)	K
"T_parasitic_refr"	-	Temperature of material making up refractive stage	float	-	\(\mathbb{R}^+\)	K
"window_AR"	-	Mimic effect of AR coating by disabling reflections	bool	-	{True, False}	-