Utilities

Collection of utility functions for eniric.

eniric.utilities.band_limits(band: str) → Tuple[float, float]

Get wavelength limits of band in microns.

Parameters:band (str) – Band letter to get wavelength range for. Returns:

• wav_min (float) – Lower wavelength bound of band in microns
• wav_max (float) – Upper wavelength bound of band in microns

eniric.utilities.band_middle(band: str) → float

Calculate band mid-point.

band: str

Band label

Returns:middle – Wavelength at middle band. Return type:float

eniric.utilities.band_selector(wav: numpy.ndarray, flux: numpy.ndarray, band: str) → Tuple[numpy.ndarray, numpy.ndarray]

Select a specific wavelength band.

Parameters:

• wav (array-like) – Wavelength values.
• flux (array-like) – Flux values.
• band (str) – Band letter to select, upper or lower case is supported. Options are (“ALL” or “”), “VIS”, “GAP”, “Z”, “Y”, “J”, “H”, “K”.

eniric.utilities.cpu_minus_one() → int

Get one less than number of CPUs available.

Returns:num_cpu_minus_1 – One less than number of CPUs, or one. Return type:int

eniric.utilities.doppler_limits(rvmax, wmin, wmax)

Calculate wavelength limits to apply if preforming doppler shift.

To avoid any edge effects within wmin and wmax after doppler shift.

Parameters:

• rvmax (float) – Maximium absolute RV offset in km/s. Uses np.abs() to constrain as absolute.
• wmin (float) – Lower wavelength limit.
• wmax (float) – Upper wavelength limit.

Returns:

• new_wmin (float) – Lower wavelength bound shifted by -rvmax
• new_wmax (float) – Lower wavelength bound shifted by +rvmax

eniric.utilities.doppler_shift_flux(wavelength: numpy.ndarray, flux: numpy.ndarray, vel: float, new_wav: Optional[numpy.ndarray] = None)

Doppler shift flux by a given velocity, return it at the original wavelengths (non-relativistic).

Apply Doppler shift to the wavelength values of the spectrum using the velocity value provided and the relation (Deltalambda / lambda = v / c)

Then linearly interpolate the flux with the new wavelength to the old wavelengths.

Parameters:

• wavelength (ndarray) – Wavelength vector
• flux (ndarray) – Flux vector
• vel (float) – Velocity to Doppler shift by in km/s.
• new_wav (Optional[ndarray]) – New wavelength array to evaluate the doppler shifted flux at. If None then defaults to new_wav=wavelength.

Returns:

new_flux – Doppler-shifted flux evaluated at new_wav.

Return type:

ndarray

eniric.utilities.doppler_shift_wav(wavelength: numpy.ndarray, vel: float)

Doppler shift wavelength by a given velocity (non-relativistic).

Apply Doppler shift to the wavelength values of the spectrum using the velocity value provided and the relation (Deltalambda / lambda = v / c)

Parameters:

• wavelength (ndarray) – Wavelength vector
• vel (float) – Velocity to Doppler shift by in km/s.

Notes

The Doppler shift is calculated using the relation

[ Deltalambda / lambda = v / c ]

Where RV is the radial velocity (in km/s), (lambda_0)` is the rest wavelength and (Deltalambda) is the wavelength shift, (lambda_{shift} - lambda_0)

eniric.utilities.issequenceforme(obj)

eniric.utilities.load_aces_spectrum(params: Union[numpy.ndarray, List[float]], photons: bool = True, air: bool = False, wl_range: Union[List[float], Tuple[float, float]] = (3000, 54000))

Load a Phoenix spectrum from the phoenix library using STARFISH.

Parameters:

• params (ndarray) – [temp, logg, metallicity(, alpha)]
• photons (bool) – Necessary conversions into photons for precisions.
• air (bool) – Convert to air wavelengths (default = False).
• wl_range ((float, float)) – Min/Max wavelength range to load. Default = (3000, 54000) Angstrom.

Returns:

• wav_micron (ndarray) – Wavelength in microns
• flux_micron (ndarray) – Photon counts per (cm**2 s) or SED/micron (within a multiplicative constant 1/(h*c)).
• Spectra available from http (//phoenix.astro.physik.uni-goettingen.de)

eniric.utilities.load_btsettl_spectrum(params: Union[numpy.ndarray, List[float]], photons: bool = True, air: bool = False, wl_range: Union[List[float], Tuple[float, float]] = (3000, 30000))

Load a BT-Settl spectrum from the CIFIST2011 library using STARFISH.

Parameters:

• params (ndarray) – [temp, logg]. Metallicity = 0, alpha = 0
• photons (bool) – Necessary conversions into photons for precisions.
• air (bool) – Convert to air wavelengths (default = False).
• wl_range ((float, float)) – Min/Max wavelength range to load. Default = (3000, 30000) Angstrom.

Returns:

• wav_micron (ndarray) – Wavelength in microns
• flux_micron (ndarray) – Photon counts per (cm**2 s) or SED/micron. (within a multiplicative constant 1/(h*c))

Notes

From BT-SETTL readme:

CIFIST2011_2015: published version of the BT-Settl grid (Baraffe et al. 2015, Allard et al. 2015. This grid will be the most complete of the CIFIST2011 grids above, but currently: Teff = 1200 - 7000K, logg = 2.5 - 5.5, [M/H] = 0.0.

Available from https://phoenix.ens-lyon.fr/Grids/BT-Settl/CIFIST2011_2015/FITS/

The BT-Settl models are Sampled at a higher rate than PHOENIX-ACES (>10 X). Therefore we cut it by factor of 10 during loading to give them similar number of points. This makes the convolutions go 10X faster.

eniric.utilities.mask_between(x: numpy.ndarray, xmin: float, xmax: float) → numpy.ndarray

Create boolean mask of x between xmin and xmax.

eniric.utilities.moving_average(x: numpy.ndarray, window_size: Union[int, float]) → numpy.ndarray

Moving average.

eniric.utilities.res2int(res: Any) → int

Convert from “100k” or “100000” to 100000.

eniric.utilities.res2str(res: Any) → str

Convert from “100000” or 100000 to “100k”.

eniric.utilities.resolutions2ints(resolution: Sequence[Any]) → List[int]

List of resolutions to list of integer resolutions.

Convert from [“100k”, “30000”] to [100000, 30000].

eniric.utilities.resolutions2strs(resolution: Sequence[Any]) → List[str]

List of resolutions to list of string resolutions.

Convert from [“100000”, 10000] to [“100k”, “10k”].

eniric.utilities.rv_cumulative(rv_vector: Union[List, numpy.ndarray], single: bool = False) → List[float]

Function that calculates the cumulative RV vector weighted_error.

eniric.utilities.rv_cumulative_full(rv_vector: Union[List, numpy.ndarray]) → numpy.ndarray

Function that calculates the cumulative RV vector weighted_error. In both directions.

eniric.utilities.silent_remove(filename: str) → None

Remove file without failing when it doesn’t exist.

eniric.utilities.wav_selector(wav: Union[numpy.ndarray, List[float]], flux: Union[numpy.ndarray, List[float]], wav_min: float, wav_max: float) → Tuple[numpy.ndarray, numpy.ndarray]

function that returns wavelength and flux within a giving range

Parameters:

• wav (array-like) – Wavelength array.
• flux (array-like) – Flux array.
• wav_min (float) – Lower bound wavelength value.
• wav_max (float) – Upper bound wavelength value.

Returns:

• wav_sel (array) – New wavelength array within bounds wav_min, wav_max
• flux_sel (array) – New wavelength array within bounds wav_min, wav_max

eniric.utilities.weighted_error(rv_vector: Union[List[float], numpy.ndarray]) → float

Function that calculates the average weighted error from a vector of errors.