Dependencies

Here is a list of dependencies for hoki. If you choose to pip install it, these will be taken care of automatically.

  • astropy

  • numpy

  • pandas

  • matplotlib

  • pyyaml

  • wheel

  • numba

  • emcee

  • corner

  • scipy

  • ppxf

hoki.cmd

This module implements the CMD infrastructure

class hoki.cmd.CMD(file, col_lim=[- 3, 7], mag_lim=[- 14, 10], res_el=0.1, bpass_version='v221', models_path='/home/fste075/BPASS_hoki_dev/bpass-v2.2-newmodels/')

Colour Magnitude Diagram Object

Parameters

  • file (str) – Location of the file containing the model inputs

  • col_lim (list of 2 integers (positive or negative), optional) – Limits on the colour range of the CMD grid, Default is [-3,7].

  • mag_lim (list of 2 integers (positive or negative), optional) – Limits on the magnitude range of the CMD grid. Default is [-14,10].

  • res_el (float or int, optional) – Resolution element of the CMD grid. The resolution element is the same for colour and magnitude. Default is 0.1.

  • bpass_version (str, optional (v221 or v222)) – The BPASS version to consider - this changes the “dummy_dictionary” that is loaded from the settings.yaml file Default = hoki.constants.DEFAULT_BPASS_VERSION

self.bpass_input

Input file given by the file parameter

Type

str

self.col_range

Colour range spanned by the grid (with res_el-sized intervals)

Type

numpy.ndarray (1D)

self.mag_range

Magnitude range spanned by the grid (with res_el-sized intervals)

Type

numpy.ndarray (1D)

self.grid

Colour-Magnitude grid.

Type

numpy.ndarray (2D)

self.path

The absolute path to the stellar models. It is set to hoki.cconstants.MODELS_PATH which you can set to the right path by using hoki.load.set_models.path().

Type

str

self.t

Class attribute - The time bins in BPASS - note they are in LOG SPACE

Type

np.ndarray 1D

self.dt

Class attribute - Time intervals between bins NOT in log space

Type

np.ndarray 1D

at_log_age(log_age)

Returns the HR diagrams at a specific age.

Parameters

log_age (int or float) – The log(age) of choice.

Returns

The CMD grid

Return type

np.ndarray 240x100

make(mag_filter, col_filters)

Make the CMD - a.k.a fill the grid

Notes

  • This may take a few seconds to a minute to run.

  • The colour will be mag_filter - filter2

  • If you later call CMD.plot() you will obtain a contour plot of mag_filter against mag_filter-filter2

Parameters

  • mag_filter (str) – Magnitude Axis Filter

  • col_filters (list of 2 str) – The two filters for the colour. The colours will be col_filter[0]-col_filter[1].

Returns

Return type

None

plot(log_age=6.8, loc=111, cmap='Greys', **kwargs)

Plots the CMD grid at a particular age

Parameters

  • log_age (float) – Must be a valid BPASS time bin

  • loc (3 integers, optional) – Location of the subplot. Default is 111.

  • cmap (str, optional) – Colour map for the contours. Default is ‘Greys’ **kwargs : matplotlib keyword arguments, optional

Returns

The plot created is returned, so you can add stuff to it, like text or extra data.

Return type

matplotlib.axes._subplots.AxesSubplot

hoki.constants

This module just contains BPASS constants and defines variables used in hoki.

BPASS and hoki constants

Functions

set_outputs_path(path) :

Changes the defaullt path to the BPASS outputs in hoki’s settings.yaml

set_default_bpass_version(version):

Changes the path to the stellar models in hoki’s settings.yaml

Variables

MODELS_PATHstr

Absolute local path to the BPASS stellar library set by the models_path string in data/settings.yaml

BPASS_TIME_BINS1D np.array

Center of the log10 age (years) BPASS time grid bins

BPASS_TIME_INTERVALS1D np.array

Edges of the log10 age (years) BPASS time grid bins

BPASS_TIME_WEIGHT_GRID2D np.array (100x100)

2D grid to contain the age (time) weights for the HRDiagrams grids

BPASS_LINEAR_TIME_EDGES1D np.array

Edges of the BPASS age grid bins transformed to linear space

BPASS_LINEAR_TIME_INTERVALS1D np.array

Center of the BPASS age grid bins in linear space

BPASS_METALLICITIESlist[str]

Valid BPASS metallicity strings in ascending metallicity order.

BPASS_NUM_METALLICITIES1D np.array

BPASS metallicities (numerical) in ascending metallicit order.

BPASS_METALLICITY_MID_POINTS1D np.array

Numerical BPASS metallicity midpoints

BPASS_EVENT_TYPESlist

Transient event types considered in the transient rate model outputs

HOKI_NOWfloat

Current age of the Universe in years. 13.799e9

BPASS_IMFSlist[str]

Valid BPASS imf strings (corresponds to the codes used in the naming of the model output files)

BPASS_WAVELENGTHS1D np.array

BPASS wavelength range covered by the model SEDs

dummy_dictdict

DEPRECATED. Dictionary relating the column names in the hoki dataframes containing the stellar model tables and the column numbers of the raw text (sneplot) files containing the stellar model tables keys: column name in the hoki dataframes values: column number in the sneplot files

dummy_dictsdict

Dictionaries relating the column names in the hoki dataframes containing the stellar model tables and the column numbers of the raw text (sneplot) files containing the stellar model tables. Read from settings.yaml and contains the keys and values for BPASS v2.2.1 and 2.2.2. keys: column name in the hoki dataframes values: column number in the sneplot files

dummy_manualdict

Dictionary containing the names of the columns (keys) in the hoki dataframes that contain the stellar model tables and their physical meaning in the simulations (values).

hoki.constants.set_default_bpass_version(version)

Changes the path to the stellar models in hoki’s settings

Parameters

version (str, v221 or v222) – Version of BPASS to consider by default.

Notes

You are going to have to reload hoki for your new default version to be taken into account.

hoki.constants.set_models_path(path)

Changes the path to the stellar models in hoki’s settings

Parameters

path (str,) – Absolute path to the top level of the stellar models this could be a directory named something like bpass-v2.2-newmodels and the next level down should contain ‘NEWBINMODS’ and ‘NEWSINMODS’.

Notes

You are going to have to reload hoki for your new path to take effect.

hoki.constants.set_outputs_path(path)

Changes the defaullt path to the BPASS outputs in hoki’s settings

Parameters

path (str,) – Absolute path to the folder containing the BPASS outputs.

Notes

You are going to have to reload hoki for your new path to take effect.

hoki.eve

hoki.eve

Author: H.F.Stevance email: hfstevance@gmail.com

Description

Implements the Eve class to be used with EvE.hdf5(alpha) that can be downloaded on Zenodo https://zenodo.org/record/7341382#.Y4y9cNLMLLo NOTE You can just download the EvE.hdf5 file - the code that is published with it just for record keeping as that is the Fortran and python code I used to create the database. If there are issues in the database and feel like going through the code to look for bugs.

hoki.load

This module implements the tools to easily load BPASS data.

hoki.load.model_input(path)

Loads inputs from one file and put them in a dataframe

Parameters

path (str) – Path to the file containing the input data.

hoki.load.model_output(path, hr_type=None)

Loads a BPASS output file

Parameters

  • path (str) – Path to the file containing the target data.

  • hr_type (str, optional) – Type of HR diagram to load: ‘TL’, ‘Tg’ or ‘TTG’.

Returns

Output Data

Return type

pandas.DataFrame or hoki.hrdiagrams.HRDiagrams object

hoki.load.set_models_path(path)

Changes the path to the stellar models in hoki’s settings

Parameters

path (str,) – Absolute path to the top level of the stellar models this could be a directory named something like bpass-v2.2-newmodels and the next level down should contain ‘NEWBINMODS’ and ‘NEWSINMODS’.

Notes

You are going to have to reload hoki for your new path to take effect.

hoki.load.unpickle(path)

Extract pickle files

hoki.hrdiagrams

This module implements the HR diagram infrastructure.

class hoki.hrdiagrams.HRDiagram(high_H_input, medium_H_input, low_H_input, hr_type)

A class containing the HR diagram data produced by BPASS.

This class is called by the functions hrTL(), hrTg() and hrTTG() in hoki.load and users should not need to create an HRDiagram object themselves.

For more details on the BPASS outputs - and therefore why the data structure is as it is - please refer to the manual: https://bpass.auckland.ac.nz/8/files/bpassv2_1_manual_accessible_version.pdf

Note

  • HRDiagram supports indexing. The indexed array is a 51x100x100 np.array that stacked the time weighted arrays

corresponding to the 3 different abundances.

  • Initialisation from a text file is done through the hoki.load functions

Parameters

  • high_H_input (np.ndarray with shape (51x100x100)) – This inputs the HR diagrams corresponding to a hydrogen abundance n1 > 0.4.

  • medium_H_input (np.ndarray with shape (51x100x100)) – This inputs the HR diagrams corresponding to a hydrogen abundance E-3 < n1 < 0.4.

  • low_H_input (np.ndarray with shape (51x100x100)) – This inputs the HR diagrams corresponding to a hydrogen abundance n1 < E-3.

  • hr_type (str - Valid options are 'TL' , 'Tg', 'TTG') – This tells the class what type of HR diagrams are being given. For more details on what the 3 options mean, consult the BPASS manual section on HR diagram isocontours.

self.high_H

HR diagrams for 51 time bins with a hydrogen abundance n1 > 0.4. Time weighted.

Type

np.ndarray (51x100x100)

self.medium_H

HR diagrams for 51 time bins with a hydrogen abundance E-3 < n1 < 0.4. Time weighted.

Type

np.ndarray (51x100x100)

self.low_H

HR diagrams for 51 time bins with a hydrogen abundance n1 < E-3. Time weighted.

Type

np.ndarray (51x100x100)

self.type

Type of HR diagram: TL, Tg or TTG

Type

str

self.high_H_not_weighted

HR diagrams for 51 time bins with a hydrogen abundance n1 > 0.4.

Type

np.ndarray (51x100x100)

self.medium_H_not_weighted

HR diagrams for 51 time bins with a hydrogen abundance E-3 < n1 < 0.4.

Type

np.ndarray (51x100x100)

self.low_H_not_weighted

HR diagrams for 51 time bins with a hydrogen abundance n1 < E-3.

Type

np.ndarray (51x100x100)

self._all_H

HR diagrams for 51 time bins - all hydrogen abundances stacked. This attribute is private because it can simply be called using the indexing capabilities of the class.

Type

np.ndarray (51x100x100)

self.high_H_stacked

HR diagram stacked for a given age range - hydrogen abundance n1 > 0.4. None before calling self.stack()

Type

np.ndarray (51x100x100)

self.medium_H_stacked

HR diagram stacked for a given age range - hydrogen abundance E-3 < n1 < 0.4. None before calling self.stack()

Type

np.ndarray (51x100x100)

self.low_H_stacked

HR diagram stacked for a given age range - hydrogen abundance E-3 > n1. None before calling self.stack()

Type

np.ndarray (51x100x100)

self.all_stacked

HR diagram stacked for a given age range - all abundances added up. None before calling self.stack()

Type

np.ndarray (51x100x100)

self.t

Class attribute - The time bins in BPASS - note they are in LOG SPACE

Type

np.ndarray 1D

self.dt

Class attribute - Time intervals between bins NOT in log space

Type

np.ndarray 1D

at_log_age(log_age)

Returns the HR diagrams at a specific age.

Parameters

log_age (int or float) – The log(age) of choice.

Returns

  • [0] : Stack of all the abundances

  • [1] : High hydrogen abundance n1>0.4

  • [2] : Medium hydrogen abundance (E-3 < n1 < 0.4)

  • [3] : Low hydrogen abundance (n1 < E-3)

Return type

Tuple of 4 np.ndarrays (100x100)

plot(log_age=None, age_range=None, abundances=(1, 1, 1), **kwargs)

Plots the HR Diagram - calls hoki.hrdiagrams.plot_hrdiagram()

Parameters

  • log_age (int or float, optional) – Log(age) at which to plot the HRdiagram.

  • age_range (tuple or list of 2 ints or floats, optional) – Age range within which you want to plot the HR diagram

  • abundances (tuple or list of 3 ints, zeros or ones, optional) – This turns on or off the inclusion of the abundances. The corresponding abundances are: (n1 > 0.4, E-3 < n1 < 0.4, E-3>n1). A 1 means a particular abundance should be included, a 0 means it will be ignored. Default is (1,1,1), meaning all abundances are plotted. Note that (0,0,0) is not valid and will return and assertion error.

  • **kwargs (matplotlib keyword arguments, optional) –

Notes

If you give both an age and an age range, the age range will take precedent and be plotted. You will get a warning if that happens though.

Returns

The plot created is returned, so you can add stuff to it, like text or extra data.

Return type

matplotlib.axes._subplots.AxesSubplot

stack(log_age_min=None, log_age_max=None)

Creates a stack of HR diagrams within a range of ages

Parameters

  • log_age_min (int or float, optional) – Minimum log(age) to stack

  • log_age_max (int or float, optional) – Maximum log(age) to stack

Returns

This method stores the stacked values in the class attributes self.high_H_stacked, self.medium_H_stacked, self.low_H_stacked and self.all_stacked.

Return type

None

hoki.hrdiagrams.plot_hrdiagram(single_hr_grid, kind='TL', loc=111, cmap='Greys', **kwargs)

Plots an HR diagram with a contour plot

Parameters

  • single_hr_grid (np.ndarray (100x100)) – One HR diagram grid.

  • kind (str, optional) – Type of HR diagram: ‘TL’, ‘Tg’, or ‘TTG’. Default is ‘TL’.

  • loc (int - 3 digits, optional) – Location to parse plt.subplot(). The Default is 111, to make only one plot.

  • cmap (str, optional) – The matplotlib colour map to use. Default is ‘RdGy’.

  • kwargs (matplotlib key word arguments to parse) –

Note

The default levels are defined such that they show the maximum value, then a 10th, then a 100th, etc… down to the minimum level. You can also use the “levels” keyword of the contour function to choose the number of levels you want (but them matplotlib will arbitrarily define where the levels fall).

Returns

The plot created is returned, so you can add stuff to it, like text or extra data.

Return type

matplotlib.axes._subplots.AxesSubplot

hoki.age

class hoki.age.wizard.AgeWizard(obs_df, model, nsamples=100)

AgeWizard object

calculate_p_given_age_range(age_range)

Calculates the probability that each source has age within age_range

Parameters

age_range (list or tuple of 2 values) – Minimum and Maximum age to consider (inclusive).

Returns

Return type

numpy.array containing the probabilities.

property most_likely_age

Finds the most likely age by finding the max value in self.calculate_sample_pdf

property most_likely_ages

Finds the most likely ages for all the sources given in the obs_df DataFrame.

hoki.age.utils.calculate_distributions(obs_df, model)

Given observations and an HR Diagram, calculates the distribution across ages (not normalised) Note to self: KEEP THIS I NEED IT

Parameters

  • obs_df (pandas.DataFrame) – Observational data. MUST contain a logT and logL column.

  • model (hoki.hrdiagrams.HRDiagrams or hoki.cmd.CMD) – BPASS HRDiagram or CMD

Returns

Return type

Age Probability Distribution Functions in a pandas.DataFrame.

hoki.age.utils.calculate_individual_pdfs(obs_df, model, nsamples=100)

Calculates the individual age PDFs for each star

Parameters

  • obs_df (pandas.DataFrame) – Observational data. MUST contain a logT and logL column (for HRD comparison) or a col and mag column (for CMD comparison)

  • model (str or hoki.hrdiagrams.HRDiagrams() hoki.cmd.CMD()) – Location of the modeled HRD or CMD. This can be an already instanciated HRDiagram or CMD() object, or a path to an HR Diagram file or a pickled CMD.

  • nsamples (int, optional) – Number of times each data point should be sampled from its error distribution. Default is 100. This only matters if you are taking errors into account.

hoki.age.utils.calculate_p_given_age_range(pdfs, age_range=None)

Calculates the probability that each source has age within age_range

Parameters

  • pdfs (pandas.DataFrame) – Age Probability Distributions Functions

  • age_range (list or tuple of 2 values) – Minimum and Maximum age to consider (inclusive).

Returns

Return type

numpy.array containing the probabilities.

hoki.age.utils.calculate_sample_pdf(distributions_df, not_you=None)

Adds together all the columns in given in DataFrame apart from the “time_bins” column

Parameters

  • distributions_df (pandas.DataFrame) – DataFrame containing probability distribution functions

  • not_you (list, optional) – List of the column names to ignore. Default is None so all the pdfs are multiplied

Returns

Return type

Combined Probability Distribution Function in a pandas.DataFrame.

hoki.age.utils.find_coordinates(obs_df, model)

Finds the coordinates on a BPASS CMD or HRD that correspond to the given observations

Parameters

  • obs_df (pandas.DataFrame) – Observational data. MUST contain a logT and logL column (for HRD comparison) or a col and mag column (for CMD comparison)

  • model (str or hoki.hrdiagrams.HRDiagrams() hoki.cmd.CMD()) – Location of the modeled HRD or CMD. This can be an already instanciated HRDiagram or CMD() object, or a path to an HR Diagram file or a pickled CMD.

hoki.age.utils.fit_lognorm_params(c, m, p, percentiles=array([0.16, 0.5, 0.84]), p0=1)

Fits the CDF of a log normal distribution to the percentiles and offset values of a parameter

Parameters

  • c (numpy.array) – 50th percentile, a.k.a median (c for center)

  • m (numpy.array) – Lower error - 1 sigma (m for minus, because this value would be subtracted to the median to retrieve the Xth percentile). Please provide the absolute value.

  • p (numpy.array) – Upper error - 1 sigma (p for plus, because these values would be added to the median to create the Yth percentile)

  • percentiles (numpy.array) –

  • p0 (numpy.array) –

hoki.age.utils.normalise_1d(distribution, crop_the_future=False)

Simple function that devides by the sum of the 1D array or DataFrame given.

hoki.csp

Author: Max Briel

Parent class of a complex stellar population

class hoki.csp.csp.CSP

Complex Stellar Population class

Notes

Parent class for CSPEventRate and CSPSpectra

now

The age of the universe.

Type

float

Author: Max Briel

Object to calculate the event rate at a certain lookback time or over binned lookback time

class hoki.csp.eventrate.CSPEventRate(data_path, imf, binary=True)

Object to calculate event rates using complex stellar formation histories.

Parameters

  • data_path (str) – Folder containing the BPASS data files (in units #events per bin)

  • imf (str) – The BPASS identifier for the IMF of the BPASS event rate files. The accepted IMF identifiers are: - “imf_chab100” - “imf_chab300” - “imf100_100” - “imf100_300” - “imf135_100” - “imf135_300” - “imfall_300” - “imf170_100” - “imf170_300”

  • binary (bool) – If True, loads the binary files. Otherwise, just loads single stars. Default=True

bpass_rates

The BPASS delay time distributions in #events/yr/M_odot per metallicity. Usage: rates.loc[log_age, (type, metallicity)]

Note

This dataframe has the following structure. The index is the log_age as a float. The column is a pandas.MultiIndex with the event types (level=0, str) and the metallicity (level=1, float)

|Event Type | Ia | IIP | ... | PISNe | low_mass | |Metallicity| 0.00001 | 0.00001 | … | 0.04 | 0.04 | | log_age |---------|———-|------|——-|----------| | 6.0 | | … | Event Rate values | 11.0 |

Type

pandas.DataFrame (51, (8, 13))

at_time(SFH, ZEH, event_type_list, t0, sample_rate=1000)

Calculates the event rates at lookback time t0 for functions as input.

Parameters

  • SFH (python callable,) –

    hoki.csp.sfh.SFH,

    list(hoki.csp.sfh.SFH, ), list(callable, )

    SFH can be the following things: - A python callable (function) which takes the lookback time and

    returns the stellar formation rate in units M_odot per yr at the given time.

    • A list of python callables with the above requirement.

    • A hoki.csp.sfh.SFH object.

    • A list of hoki.csp.sfh.SFH objects.

  • ZEH (callable, list(callable, )) –

    ZEH can be the following things: - A python callable (function) which takes the lookback time and

    returns the metallicity at the given time.

    • A list of python callables with the above requirement.

  • event_type_list (list(str, )) – A list of BPASS event types. The available types are: - Ia - IIP - II - Ib - Ic - LGRB - PISNe - low_mass

  • t0 (float) – The moment in lookback time, where to calculate the the event rate

  • sample_rate (int) – The number of samples to take from the SFH and metallicity evolutions. Default = 1000. If a negative value is given, the BPASS binning to calculate the event rates.

Returns

Returns a numpy.ndarray containing the event rates for each sfh and metallicity pair (N) and event type (M) at the requested lookback time. Usage: event_rates[1][“Ia”] (Gives the Ia event rates for the second sfh and metallicity history pair)

Return type

numpy.ndarray (N, M) [nr_sfh, nr_event_types]

grid_at_time(SFH_list, time_points, event_type_list, t0, sample_rate=1000)

Calculates event rates for the given BPASS event types for the given SFH in a 2D grid (over BPASS metallicity and time_points)

Parameters

  • SFH_list (numpy.ndarray (N, 13, M) [nr_sfh, metalllicities, time_points]) – A list of N stellar formation histories divided into BPASS metallicity bins, over lookback time points with length M.

  • time_points (numpy.ndarray (M)) – An array of the lookback time points of length N2 at which the SFH is given in the SFH_list.

  • event_type_list (list(str, )) –

    A list of BPASS event types.

    The available types are: - Ia - IIP - II - Ib - Ic - LGRB - PISNe - low_mass

  • t0 (float) – The moment in lookback time, where to calculate the the event rate

  • sample_rate (int) – The number of samples to take from the SFH and metallicity evolutions. Default = 1000. If a negative value is given, the BPASS binning to calculate the event rates.

Returns

event_rate_list – A numpy array containing the event rates per SFH (N), per metallicity (13), per event type (nr_events) at t0.

Return type

numpy.ndarray (N, 13, nr_events)

grid_over_time(SFH_list, time_points, event_type_list, nr_time_bins, return_time_edges=False)

Calculates event rates for the given BPASS event types for the given Stellar Formation Histories

Parameters

  • SFH_list (numpy.ndarray (N, 13, M) [nr_sfh, metalllicities, time_points]) – A list of N stellar formation histories divided into BPASS metallicity bins, over lookback time points with length M.

  • time_points (numpy.ndarray (M)) – An array of the lookback time points of length N2 at which the SFH is given in the SFH_list.

  • event_type_list (list(str, )) –

    A list of BPASS event types.

    The available types are: - Ia - IIP - II - Ib - Ic - LGRB - PISNe - low_mass

  • nr_time_bins (int) – The number of time bins in which to divide the lookback time

  • return_time_edges (bool) – If True, also returns the edges of the lookback time bins. Default=False

Returns

event_rate_list – ((N, 13, nr_events, nr_time_bins), time_edges) A numpy array containing the event rates per galaxy (N), per metallicity (13), per event type (nr_events) and per time bins (nr_time_bins).

If return_time_edges=True, returns a numpy array containing the event rates and the time edges, eg. out[0]=event_rates_list out[1]=time_edges.

Return type

numpy.ndarray (N, 13, nr_events, nr_time_bins)

over_time(SFH, ZEH, event_type_list, nr_time_bins, return_time_edges=False)

Calculates the event rates over lookback time for functions as input.

Parameters

  • SFH (python callable,) –

    hoki.csp.sfh.SFH,

    list(hoki.csp.sfh.SFH, ), list(callable, )

    SFH can be the following things: - A python callable (function) which takes the lookback time and

    returns the stellar formation rate in units M_odot per yr at the given time.

    • A list of python callables with the above requirement.

    • A hoki.csp.sfh.SFH object.

    • A list of hoki.csp.sfh.SFH objects.

  • ZEH (callable, list(callable, )) –

    ZEH can be the following thins: - A python callable (function) which takes the lookback time and

    returns the metallicity at the given time.

    • A list of python callables with the above requirement.

  • event_type_list (list(str, )) –

    A list of BPASS event types.

    The available types are: - Ia - IIP - II - Ib - Ic - LGRB - PISNe - low_mass

  • nr_time_bins (int) – The number of bins to split the lookback time into.

  • return_time_edges (bool) – If True, also returns the edges of the lookback time bins. Default=False

Returns

((nr_sfh, nr_event_types, nr_time_bins), nr_time_bins)

The event rates in a 3D matrix with sides, the number of SFH-Z pairs, the number of events selected, and the number of time bins choosen.

If return_time_edges=False, returns a numpy.ndarray containing the event rates. Usage: event_rates[1][“Ia”][10]

(Gives the Ia event rates in bin number 11 for the second sfh and metallicity history pair)

If return_time_edges=True, returns a numpy array containing the event rates and the edges, eg. out[0]=event_rates out[1]=time_edges.

Return type

numpy.ndarray (nr_sfh, nr_event_types, nr_time_bins),

Authors: Max Briel and Heloise Stevance

Object to contain the stellar formation history.

class hoki.csp.sfh.SFH(time_axis, sfh_type, parameters_dict=None, sfh_arr=None)

An object to contain a stellar formation history of a population.

time_axis

An array containing the given time points of the stellar formation rate

Type

numpy.array

mass_per_bin(time_edges, sample_rate=25)

Gives the mass per bin for the given edges in time.

time_edgesnumpy.ndarray

The edges of the bins in which the mass per bin is wanted in yrs.

numpy.ndarray

The mass per time bin given the time edges.

hoki.csp.sfh.burst_sfh(time_bins, sfr, burst_time)

Burst star formation history

Parameters

  • time_bins (list or numpy.ndarray) – Time bins

  • sfr (int or float) – Value of the desired star formation rate at the burst time

  • burst_time (int or float) – Time of the star burst

Returns

Return type

Array containing the star formation history corresponding to the given time_bins

hoki.csp.sfh.constant_sfh(time_bins, sfr)

Constant star formation history

Parameters

  • time_bins (list or numpy.ndarray) – Time bins

  • sfr (int or float) – Value of the desired constant star formation rate.

Returns

Return type

Array containing the star formation history corresponding to the given time_bins

hoki.csp.sfh.dble_pwr_law(time_bins, tau, alpha, beta, factor=1)

Double Power Law star formation history

Parameters

  • time_bins (list or numpy.ndarray) – Time bins

  • tau (float or int) –

  • alpha (float or int) –

  • beta (float or int) –

  • factor (float or int, optional) – Default = 1

Returns

Return type

Array containing the star formation history corresponding to the given time_bins

hoki.csp.sfh.delayed_exp_sfh(time_bins, tau, T0, factor=1)

Delayed exponential star formation history

Parameters

  • time_bins (list or numpy.ndarray) – Time bins

  • tau (float or int) –

  • T0 (float or int) –

  • factor (float or int, optional) – Default = 1

Returns

Return type

Array containing the star formation history corresponding to the given time_bins

hoki.csp.sfh.exp_sfh(time_bins, tau, T0, factor=1)

Exponential star formation history

Parameters

  • time_bins (list or numpy.ndarray) – Time bins

  • tau (float or int) –

  • T0 (float or int) –

  • factor (float or int, optional) – Default = 1

Returns

Return type

Array containing the star formation history corresponding to the given time_bins

hoki.csp.sfh.lognormal(time_bins, tau, T0, factor=1)

Lognormal star formation history

Parameters

  • time_bins (list or numpy.ndarray) – Time bins

  • tau (float or int) –

  • T0 (float or int) –

  • factor (float or int, optional) – Default = 1

Returns

Return type

Array containing the star formation history corresponding to the given time_bins

hoki.csp.sfh.sfherrormessage(func, *args, **kwargs)

A decorator to automate a repeated error message.

Author: Max Briel

Utilities to be used in the complex stellar populations module

hoki.csp.utils.mass_per_bin(sfh_function, time_edges, sample_rate=25)

Calculates the mass per bin for the given edges in time

Notes

The default sample_rate is set to 25 for a untested balance between speed and accuracy

sfh_functioncallable

A python callable (function) giving the stellar formation rate at a given lookback time. For faster calculations give a vector optimised function.

time_edgesnumpy.ndarray

The edges of the bins in which the mass per bin is wanted in yrs.

sample_rateint

The number of samples to take to use for the trapezodial integration. Default = 25

numpy.ndarray [len(time_edges)-1]

The mass per time bin.

hoki.csp.utils.metallicity_per_bin(Z_function, time_edges)

Gives the metallicity per bin for the given edges in time.

Z_functionfunction

A function giving the metallicity history given a lookback time.

time_edgesnumpy.ndarray

The edges of the bins in which the mass per bin is wanted in yrs.

numpy.ndarray [len(time_edges)-1]

The average metallicity per time bin

hoki.csp.utils.trapz_loop(dp, fp, sample_rate)

Perform a trapezodial integration over subsections of the given arrays.

Notes

dp and fp are split into a number of bins [(N-1)/sample_rate]. Each subsection is integrated using the _optimised_trapezodial_rule. An array containing the integral for each subsection is returned.

Parameters

  • dp (numpy.ndarray (N)) – Time points

  • fp (numpy.ndarray (N)) – Function values at the time points

  • sample_rate (int) – The sample rate over which to integrate the values. (N-1) has to be divisible by sample_rate

Returns

An array containing the integrals over bins separated by sample_rate

Return type

numpy.ndarray (N-1)/sample_rate

hoki.sedfitting

Note that the modules kvn and lordcommander will be renamed in v1.7.2

class hoki.sedfitting.lordcommander.LordCommander(wl_obs, norm_fluxes, norm_noises, median_flux_ls, wl_fits, kvn)

LordCommander is a pipeline to run the ppxf fits on a whole array of spectra (e.g. galaxy) It creates a bunch of tables (DataFrames) to store the data and then can save it to HDF5

SCALE_FACTOR:

Contains the median of the observed spectra (used for the normalisation)

DYNAMICS:

Contains the best dispersion and Line Of Sight Velocity (LOSV)

BEST_FIT:

Contains the best fits from ppxf

SFH:

Contains the metalicity and ages of each of the templates selected to make the best fit

MATCH_SPECTRA:

Contains all the spectra used to create the best fit (that correspond to each row of SFH)

MATCH_APOLY:

Contains the additive polynomials needed to make the best fit - may be empty

MATCH_MPOLY:

Contains the multiplicative polynomials needed to make the best fit - may be empty

CHI2:

Contains the values of chi2 for each best fit

FLAGS:

Contains the flags. During the fitting procedure, flags are created when the chi2 value or dynamical parameters are higher than the median for the whole galaxy. => There are flags for deviations by 2, 3 and 5 standard deviations. The value of the flag is:

  • 2,3,5 for the Chi2

  • 20,30,50 for the LOSV

  • 200,300,500 for the dispersion.

So a TOTAL flag with value 553 has a 3 sigma deviation in the Chi2, a 5 sigma diviation in the LOSV and a 5 sigma deviation in the dispersion.

run(start, moments, degree, vsyst, clean, goodpixels_func, reddening=None)

Fits the spectra in a big loop.

Parameters

  • start (list of 2 values) – [LOSV_guess, dispersion_guess]

  • moments (integer) – See ppxf manual

  • degree (integer) – See ppxf manual

  • vsyst (float) – See ppxf manual

  • clean (bool) – Whether to do sigma clipping

  • goodpixels_func (callable) – The function to determine the good pixels. It needs to take in a dictionary that contains they keys: flux and `wl`(Might expand that dictionary at a later date if I need more paramters).

Returns

Return type

None

save(filepath, folder)

Saves data to HDF5 file.

Parameters

  • filepath (str) – path to the file

  • folder (str) – path WITHIN the file

Returns

Return type

None