mangadap.par.emissionmomentsdb module¶

Container class for the database of emission-line bandpass filters used for non-parameteric measurements of emission-line flux and velocity moments.

Todo

Combine this with the main emissionlinemoments.py file.

License:

Copyright (c) 2015, SDSS-IV/MaNGA Pipeline Group: Licensed under BSD 3-clause license - see LICENSE.rst

Source location:

$MANGADAP_DIR/python/mangadap/par/emissionmomentsdb.py

Imports and python version compliance:

from __future__ import division
from __future__ import print_function
from __future__ import absolute_import
from __future__ import unicode_literals

import sys
import warnings
if sys.version > '3':
    long = int

import os.path
import numpy

from pydl.goddard.astro import airtovac
from pydl.pydlutils.yanny import yanny
from .parset import ParDatabase
from .spectralfeaturedb import available_spectral_feature_databases, SpectralFeatureDBDef
from ..proc.bandpassfilter import BandPassFilterPar
from ..proc.util import select_proc_method

Class usage examples:

Emission-line moment databases are defined using SDSS parameter files. To define a database, you can use one of the default set of available emission-line moment databases (see available_emission_bandpass_filter_databases()):

from mangadap.par.emissionmomentsdb import EmissionMomentsDB
p = EmissionMomentsDB('STRONG')

The above call requires that the $MANGADAP_DIR environmental variable is set. If it is not, you can define it’s location, as in:

from mangadap.par.emissionmomentsdb import EmissionMomentsDB
p = EmissionMomentsDB('STRONG', dapsrc='/path/to/dap/source')

Finally, you can create your own SDSS-style parameter file with your own emission line passbands to use. Example files are provided in $MANGADAP_DIR/data/emission_bandpass_filters with a companion README file. With your own file, you have to point to the file using SpectralFeatureDBDef, which you can then pass to EmissionMomentsDB:

from mangadap.par.spectralfeaturedb import SpectralFeatureDBDef
from mangadap.par.emissionmomentsdb import EmissionMomentsDB
d = SpectralFeatureDBDef(key='USER',
                         file_path='/path/to/parameter/file')
p = EmissionMomentsDB('USER', emldb_list=d)

The reference frame of the emission-line passband wavelengths must be defined as either vacuum or air, using ‘in_vacuum’. It is expected that the object spectra to be analyzed are calibrated to vacuum wavelengths. If ‘in_vacuum’ is false, this class will use mangadap.util.idlutils.airtovac() to convert the emission-line bandpass-filter wavelengths to vacuum.

Revision history:

Mar 2016: Original implementation by K. Westfall (KBW)
May 2016: (KBW) Switch to using pydl.pydlutils.yanny and
pydl.goddard.astro.airtovac instead of internal functions
Oct 2017: (KBW) Add function to return channel names.

class mangadap.par.emissionmomentsdb.EmissionMomentsDB(database_key, emldb_list=None, dapsrc=None)[source]¶

Bases: mangadap.par.parset.ParDatabase

Basic container class for the database of emission-line bandpass filter parameters. See mangadap.parset.ParDatabase for additional attributes.

Parameters:

database_key (str) – Keyword selecting the database to use.
emldb_list (list) – (Optional) List of SpectralFeatureDBDef objects that define the parameters required to setup the emission-line bandpass filter database. The database_key must select one of the objects in this list.
dapsrc (str) – (Optional) Root path to the DAP source directory. If not provided, the default is defined by mangadap.config.defaults.dap_source_dir().

database¶

Keyword of the selected database to use.

Type:	str

neml¶

Number of emission-line bandpass filters in the database

Type:	int

channel_names()[source]¶

mangadap.par.emissionmomentsdb.available_emission_bandpass_filter_databases(dapsrc=None)[source]¶

Return the list of database keys and file names for the available emission-line moment databases. The currently available databases are:

KEY	N	Description
STRONG	13	A subset of mostly strong lines.
EXTENDED	21	Include HeI/II, SIII, Hgam-Heps

This is a simple wrapper for mangadap.par.spectralfeaturedb.available_spectral_feature_databases().

Parameters:	dapsrc (str) – (Optional) Root path to the DAP source directory. If not provided, the default is defined by `mangadap.config.defaults.dap_source_dir()`.
Returns:	An list of `SpectralFeatureDBDef` objects, each of which defines a unique set of absorption-line indices (see `mangadap.proc.bandpassfilter.BandPassFilterPar`).
Return type:	list

Todo

Add backup function for Python 2.
Somehow add a python call that reads the databases and constructs the table for presentation in sphinx so that the text above doesn’t have to be edited with changes in the available databases.