Public Utilities Reference

These utility functions are used to prepare atmosphere screens and source cubes in gateau. More...

Functions
None	gateau.atmosphere_utils.prep_atm_ARIS (str path_to_aris, float radius_tel, float edge_taper=-10, int num_threads=NCPU)
	Prepare ARIS atmospheric screens for usage in gateau. More...
np.ndarray	gateau.source_utils.convolve_source_cube (np.ndarray source_cube, np.ndarray az_arr, np.ndarray el_arr, np.ndarray f_src, float radius_tel, float edge_taper=-10, int num_threads=NCPU)
	Prepare source cube for usage in gateau. More...

Detailed Description

These utility functions are used to prepare atmosphere screens and source cubes in gateau.

Function Documentation

convolve_source_cube()

np.ndarray gateau.source_utils.convolve_source_cube	(	np.ndarray	source_cube,
		np.ndarray	az_arr,
		np.ndarray	el_arr,
		np.ndarray	f_src,
		float	radius_tel,
		float	edge_taper = -10,
		int	num_threads = NCPU
	)

Prepare source cube for usage in gateau.

This function takes a source cube, representing an astronomical source. The cube should be a 3-dimensional Numpy array containing specific intensity in S.I. units. The first axis corresponds to azimuth, the second to elevation, and the last to source frequencies. Then, the far-field pattern at each source frequency is calculated from the 2-dimensional Fourier transform of the aperture illumination. Circularly symmetric Gaussian illumination is assumed. Each azimuth-elevation slice in the source cube is then convolved by its respective far-field pattern. Run this function at least once per source cube/telescope model combination.

Parameters

source_cube	3-dimensional Numpy array containg source. Axes represent azimuth, elevation, and source freuencies. The unit of the source cube must be specific intensity, in S.I. units.
az_arr	Numpy array containing azimuth coordinates, in degrees.
el_arr	Numpy array containing elevation coordinates, in degrees.
f_src	Numpy array containing source frequencies in Hertz.
radius_tel	Radius of primary aperture of telescope, in meters.
edge_taper	Power level of illumination pattern at rim of primary aperture, in decibel. Defaults to -10 dB.
num_threads	Number of CPU threads to use for the ARIS screen preparation. Defaults to the total number of threads on the CPU.

Returns

far-field pattern convolved source cube, in units of spectral power / beam. The cube is also 3-dimensional, with the axes representing the same coordinates as the input cube.

prep_atm_ARIS()

None gateau.atmosphere_utils.prep_atm_ARIS	(	str	path_to_aris,
		float	radius_tel,
		float	edge_taper = -10,
		int	num_threads = NCPU
	)

Prepare ARIS atmospheric screens for usage in gateau.

This function takes a path to dEPL ARIS screens, converts this to PWV using the Smith-Weintraub relation, and filters this with a truncated Gaussian corresponding to the power pattern of the primary aperture. The output screens are stored in a folder named '/prepd/', which is stored in the same folder as the ARIS screens. Run this function at least once per ARIS collection/telescope model combination.

Parameters

path_to_aris	String containing the path to the folder containing the ARIS screens. The path can either be absolute or relative to your working directory.
radius_tel	Radius of primary aperture of telescope, in meters.
edge_taper	Power level of illumination pattern at rim of primary aperture, in decibel. Defaults to -10 dB.
num_threads	Number of CPU threads to use for the ARIS screen preparation. Defaults to the total number of threads on the CPU.