- JWST Cycle 1 Proposal Opportunities
- JWST Cycle 1 Guaranteed Time Observations Call for Proposals
- • JWST Director's Discretionary Early Release Science Call for Proposals
- • JWST Call for Proposals for Cycle 1
- James Webb Space Telescope Call for Proposals for Cycle 1
- •JWST Cycle 1 Proposal Checklist and Resources
- •JWST Cycle 1 Proposal Policies and Funding Support
- JWST Cycle 1 Proposal Categories
- •JWST Cycle 1 Observation Types and Restrictions
- •JWST Cycle 1 Proposal Preparation
- •JWST Cycle 1 Single-Stream Proposal Process
- •JWST Cycle 1 Special Submission Requirements
- •JWST Cycle 1 Observation Mode Restrictions
- •JWST Cycle 1 Proposal Selection Process
- •JWST Cycle 1 Awarded Program Implementation
- •JWST Cycle 1 Proposal Science Categories and Keywords
- JWST General Science Policies
- • JWST Observing Overheads and Time Accounting Policy
- • JWST Duplicate Observations Policy
- • JWST Science Parallel Observation Policies and Guidelines
- • JWST Observing Program Modification Policy
- • Policies for the Telescope Time Review Board
- • JWST Target of Opportunity Program Activation
- NASA-SMD Policies and Guidelines for the Operations of JWST at STScI
- •Policy 1 - Limitations on the Use of Funds for the Research of General Observers and Archival Research
- •Policy 2 - Data Rights and Data Dissemination
- •Policy 3 - Data Requests and Facilities
- •Policy 4 - Post-Launch Commissioning of JWST
- •Policy 5 - Clarification of Extensions of Exclusive Access Data to Public Affairs Activities
- •Policy 6 - Distribution of JWST Science Data Obtained from Investigations Other Than Those Selected Through the Peer-review Process
- •Policy 7 - NASA Needs for Support for Other Missions
- •Policy 8 - Definition of Observing Time
- •Policy 9 - Allocation of Guaranteed Observing Time to Scientists Selected Under AO 01-OSS-05 and Through NASA-ESA-CSA Agreements
- •Policy 10 - Redistribution of Guaranteed Observing Time Among Observers
- •Policy 11 - Protection of Science Programs Associated With Guaranteed Time
- •Policy 12 - Education and Public Outreach
- Methods and Roadmaps
- JWST Imaging
- • JWST Slit Spectroscopy
- • JWST Slitless Spectroscopy
- JWST High-Contrast Imaging
- •Contrast Considerations for JWST High-Contrast Imaging
- •JWST Coronagraphic Observation Planning
- •JWST Coronagraphic Sequences
- •JWST Coronagraphy in ETC
- •JWST High-Contrast Imaging in APT
- •JWST High-Contrast Imaging Inner Working Angle
- •JWST High-Contrast Imaging Optics
- •JWST Small Grid Dither Technique
- •MIRI-Specific Treatment of Limiting Contrast
- •NIRCam-Specific Treatment of Limiting Contrast
- •NIRISS AMI-Specific Treatment of Limiting Contrast
- •Selecting Suitable PSF Reference Stars for JWST High-Contrast Imaging
- JWST Integral Field Spectroscopy
- JWST MOS Spectroscopy
- JWST Time-Series Observations
- •Overview of Time-Series Observation (TSO) Modes
- •Noise Sources for Time-Series Observations
- •Sensitivity of Time-Series Observation Modes
- •Bright limits of Time-Series Observation Modes
- •Preparing Time-Series Observations with JWST
- •Target Acquisition for Time-Series Observations
- •NIRCam-Specific Time-Series Observations
- •NIRISS-Specific Time-Series Observations
- •MIRI-Specific Time-Series Observations
- JWST Moving Target Observations
- •Field of Regard Considerations for Moving Targets
- •Instrument-Specific Considerations for Moving Targets
- •JWST Moving Target Calibration and Processing
- •JWST Moving Target Ephemerides
- •JWST Moving Target Observing Procedures
- •JWST Moving Target Policies
- JWST Moving Targets in APT
- •JWST Moving Targets in ETC
- •JWST Moving Target Useful References and Links
- •Overheads for Moving Targets
- •Moving Target Recommended Strategies
- JWST Parallel Observations
- • JWST Target of Opportunity Observations
- • General Proposal Planning Workflow
- Observatory Functionality
- • JWST Position Angles, Ranges, and Offsets
- • JWST Instrument Ideal Coordinate Systems
- JWST Background Model
- • JWST Guide Stars
- • JWST Mosaic Overview
- • JWST Dithering Overview
- JWST Duplication Checking
- JWST Observing Overheads and Time Accounting Overview
- •JWST Observing Overheads Summary
- •JWST Slew Times and Overheads
- JWST Instrument Overheads
- Observing Overheads for NIRCam Imaging
- • JWST Data Rate and Data Volume Limits
- Observatory Hardware
- • JWST Observatory Overview
- • JWST Observatory Coordinate System and Field of Regard
- • JWST Field of View
- • JWST Orbit
- JWST Spacecraft Bus
- • JWST Pointing Performance
- • JWST Telescope
- • JWST Wavefront Sensing and Control
- • JWST Momentum Management
- • JWST Integrated Science Instrument Module
- • JWST Solid State Recorder
- • JWST Target Viewing Constraints
- • Fine Guidance Sensor, FGS
- Astronomers Proposal Tool
- • JWST Astronomers Proposal Tool Overview
- • APT Proposal Information
- APT Targets
- • APT Observations
- • APT Visit Splitting
- JWST APT Coordinated Parallel Observations
- • JWST APT Pure Parallel Observations
- • APT Target Acquisition
- JWST APT Mosaic Planning
- • APT Special Requirements
- • APT Visit Planner
- • JWST APT Aladin Viewer
- • APT Smart Accounting
- • JWST APT Target Confirmation Charts
- • APT Submitting Your JWST Proposal
- JWST APT Functionality Examples
- • JWST APT Help Features
- • JWST APT Training Examples and Video Tutorials
- Other Tools
- Mid Infrared Instrument
- • MIRI Overview
- MIRI Observing Modes
- MIRI Instrumentation
- MIRI Operations
- MIRI Target Acquisitions
- MIRI Dithering
- MIRI Mosaics
- •MIRI MRS Simultaneous Imaging
- MIRI Time Series Observations
- MIRI Predicted Performance
- MIRI APT Templates
- MIRI Observing Strategies
- MIRI Example Programs
- •MIRI Coronagraphy of GJ 758 b
- MIRI and NIRSpec Observations of SN1987A
- •MIRI and NIRCam Coronagraphy of the Debris Disk Archetype around Beta Pictoris
- •MIRI IFU and NIRSpec Observations of Cas A
- Near Infrared Camera
- • NIRCam Overview
- NIRCam Observing Modes
- NIRCam Instrumentation
- •NIRCam Field of View
- •NIRCam Modules
- •NIRCam Optics
- •NIRCam Dichroics
- •NIRCam Pupil and Filter Wheels
- •NIRCam Filters
- •NIRCam Coronagraphic Occulting Masks and Lyot Stops
- •NIRCam Filters for Coronagraphy
- •NIRCam Grisms
- •NIRCam Weak Lenses
- NIRCam Detectors
- NIRCam Operations
- NIRCam Dithers and Mosaics
- •NIRCam Coronagraphic PSF Estimation
- •NIRCam Coronagraph Astrometric Confirmation Images
- •NIRCam Apertures
- NIRCam Target Acquisition Overview
- NIRCam Predicted Performance
- NIRCam APT Templates
- NIRCam Observing Strategies
- NIRCam Example Programs
- NIRCam Imaging and NIRISS WFSS of Galaxies Within Lensing Clusters
- •NIRCam Coronagraphy of HR8799 b
- •NIRCam Deep Field Imaging
- NIRCam Grism Time-Series Observations of GJ 436b
- NIRCam Time-Series Imaging of HAT-P-18 b
- •NIRCam WFSS Deep Galaxy Observations
- •NIRCam and MIRI Coronagraphy of the Debris Disk Archetype around Beta Pictoris
- Near Infrared Imager and Slitless Spectrograph
- • NIRISS Overview
- NIRISS Observing Modes
- NIRISS Instrumentation
- NIRISS Operations
- NIRISS Predicted Performance
- NIRISS APT Templates
- NIRISS Observing Strategies
- NIRISS Example Programs
- NIRISS WFSS and NIRCam Imaging of Galaxies Within Lensing Clusters
- NIRISS AMI Observations of Extrasolar Planets Around a Host Star
- NIRISS SOSS Time-Series Observations of HAT-P-1
- Near Infrared Spectrograph
- NIRSpec Overview
- NIRSpec Observing Modes
- NIRSpec Instrumentation
- •NIRSpec Optics
- •NIRSpec Dispersers and Filters
- NIRSpec Detectors
- •NIRSpec Micro-Shutter Assembly
- •NIRSpec Integral Field Unit
- •NIRSpec Fixed Slits
- NIRSpec Operations
- NIRSpec Dithers and Nods
- NIRSpec MOS Operations
- NIRSpec IFU Operations
- •NIRSpec FS Operations
- •NIRSpec BOTS Operations
- NIRSpec Target Acquisition
- NIRSpec Predicted Performance
- NIRSpec APT Templates
- NIRSpec Multi-Object Spectroscopy APT Template
- •NIRSpec MOS Proposal Checklist
- •NIRSpec MSA Planning Tool, MPT
- NIRSpec MPT - Catalogs
- •NIRSpec MPT - Planner
- NIRSpec MPT - Manual Planner
- •NIRSpec MPT - Plans
- •NIRSpec MPT - Parameter Space
- •NIRSpec MSA Spectral Visualization Tool Help
- •NIRSpec Observation Visualization Tool Help
- •NIRSpec IFU Spectroscopy APT Template
- •NIRSpec Fixed Slit Spectroscopy APT Template
- •NIRSpec Bright Object Time-Series APT Template
- •NIRSpec FS and IFU Mosaic APT Guide
- NIRSpec Multi-Object Spectroscopy APT Template
- NIRSpec Observing Strategies
- •NIRSpec Background Recommended Strategies
- •NIRSpec Bright Spoilers and the IFU Recommended Strategies
- •NIRSpec Detector Recommended Strategies
- •NIRSpec Dithering Recommended Strategies
- •NIRSpec MOS Recommended Strategies
- •NIRSpec MSA Leakage Subtraction Recommended Strategies
- •NIRSpec Target Acquisition Recommended Strategies
- NIRSpec Example Programs
- NIRSpec and MIRI Observations of SN1987A
- •NIRSpec and MIRI IFU Observations of Cas A
- NIRSpec Bright Object Time Series Observations of GJ 1214b
- NIRSpec MOS Deep Extragalactic Survey
- •NIRSpec MOS Observations of NGC 346
- Understanding Data Files
- Obtaining Data
- Data Processing and Calibration Files
- JWST Data Reduction Pipeline
- • Primer and Tutorials
- • Pipeline User's Guide
- • Software Reference Documentation
- Algorithm Documentation
- • Obtaining and Installing Software
This page describes the keywords in the JWST Pandeia configuration dictionary, provides valid keyword values (when applicable), and provides examples of adjusting Pandeia configuration dictionaries to produce particular outputs.
Pandeia configuration dictionaries are python dictionaries, and may be created or edited as such. Whilst it is possible to create a Pandeia configuration dictionary from scratch, it is generally preferable to modify an existing dictionary.
Creating Pandeia configuration dictionaries
Pandeia configuration dictionaries may be created entirely from scratch, imported from JSON files, or created by using Pandeia's "build_default_calc" function. Instructions on importing pandeia configuration information from JSON files can be found on the quickstart page.
Configuration dictionary structure
The Pandeia configuration dictionary has the following structure:
calculation: dictionary, contains flags to turn on and off the various calculation parameters
noise: dictionary, contains flags to turn on and off the available noise parameters
crs: boolean, flag to turn on and off the cosmic ray contribution to the noise value
darkcurrent: boolean, flag to turn on and off the dark current contribution to the noise value
ffnoise: boolean, flag to turn on and off the flat field contribution to the noise
readnoise: boolean, flag to turn on and off readout noise
rn_correlation: boolean, flag to turn on and off correlated readnoise
effects: dictionary, contains flags to turn on and off detector and sky effects
background: boolean, flag to turn on and off whether the background count rate is included. Note that in order to apply a background, this value and the background_subtraction key in the strategy dictionary must be set to True.
ipc: boolean, flag to turn on and off inter-pixel capacitance
saturation: boolean, flag to turn on and off checks for saturation, and the effects of saturation and signal-to-noise
configuration: dictionary, contains parameters related to the scene being observed and the instrument configuration.
scene_size: floating point value, the default size of the scene in arc seconds (the scene will always be a square, with size values referring to the length of a single side)
max_scene_size: floating point value, the maximum size to which the scene can grow in order to include all sources.
dynamic_scene: boolean, whether the scene should dynamically grow to include all sources (up to a maximum of max_scene_size)
instrument: dictionary, contains the instrument configuration parameters
aperture: string, the aperture to be used.
disperser: string, the disperser to be used (if any)
filter: string, the filter to be used (if any)
instrument: string, the instrument to be used (if using build_default_calc, the value provided for instrument will be set here)
mode: string, the mode to be used (if using build_default_calc, the value provided for mode will be set here)
detector: dictionary, contains the detector configuration
ngroup: integer, the number of groups in each ramp
nint: integer, the number of ramps in each exposure
nexp: integer, the number of exposures
subarray: string, which subset of the detector to use (or 'full' to use the entire detector)
readmode: string, which readout mode to use
strategy: dictionary, what observing strategy to use. The exact contents vary by strategy, but a typical strategy contains:
aperture_size: floating point, the size of the exposure aperture
sky_annulus: list of 2 floating point values. The inner and outer radius of the annulus in which the sky countrate will be measured
units: string, the units of the aperture size and sky annulus
background_subtraction: boolean, flag to turn background subtraction on and off. Note that in order to apply a background this value and the background key in the calculation:effects dictionary must be set to True
target_type: string, optional: the type of target being observed.
target_source: integer, which source to include in the observation. Only checked if 'target_type' is 'source'.
display_string: string, for information, the name of the observing method being used.
method: string, the internal function name of the observing method being used.
target_xy: list of 2 floating point values: the pixel location of the target
background: the background value. Either a string with value 'none', 'minzodi', or 'ecliptic', or a list of 2 arrays containing the wavelength (microns) and background flux (MJy/sr).
- background_level: the background level. A string with the value 'low', 'medium', or 'high'; if background is 'minzodi', the value 'benchmark' is also allowed.
scene: list of dictionaries, one for each source in the scene. Each source dictionary includes:
position: dictionary, containing information about the source position. By default, all parameters should always be present in the position dictionary, but Pandeia will interpret any missing parameter as having the value 0.
position_parameters: list of strings, one for each parameter present. Possible parameters are:
x_offset: float, the offset of the source in the x direction from the centre of the scene, in arcseconds
y_offset: float, the offset of the source in the y direction from the centre of the scene, in arcseconds
orientation: float, the angle of the source with respect to the positive scene x axis, in degrees
Each parameter named in the position parameters list must be present in the position dictionary as a separate key of the defined type.
shape: dictionary, containing information about the source shape
geometry: string, one of 'point', 'flat', 'gaussian2d', 'sersic', 'sersic_scale', or 'power'. Different shapes require different shape parameters, as follows:
point: Does not require any other parameters. Parameters present will be ignored.
flat: Requires the parameters 'major' and 'minor' to be present.
gaussian2d: Requires the parameters 'major' and 'minor' to be present.
sersic: Requires the parameters 'major', 'minor', and 'sersic_index' to be present.
- sersic_scale: Requires the parameters 'major', 'minor', and 'sersic_index' to be present.
- power: Requires the parameters 'r_core' and 'power_index' to be present.
shape_parameters: list of strings, one for each parameter present. Possible parameters are:
major: float, length of the major axis, in arcseconds.
minor: float, length of the minor axis, in arcseconds.
sersic_index: float, index of the sersic profile. An index of 1.0 yields an exponential profile, 0.5 a gaussian profile, and 4.0 a de Vaucouleurs profile.
- power_index: float, index of the power law spatial profile.
- norm_method: string, defines where the profile is to be normalized. Possible values are "integ_infinity", "surf_center", and "surf_scale". For flat profiles, "surf_scale" is not valid; for power law profiles, neither "surf_scale" nor "integ_infinity" are valid.
- surf_area_units: string, defines the area unit of the surface brightness normalization. Possible values are "null" (for integ_infinity only), "arcsec^2", or "sr".
Each parameter named in the shape parameters list must be present in the shape dictionary as a separate key of the defined type.
spectrum: dictionary, containing information about the source SED.
name: string, name of the source. Provided for information, not referenced by the engine during the calculation.
spectrum_parameters: list of strings, one for each parameter present. Possible parameters are:
redshift: float, redshift of the source. Redshift is applied after the spectrum has been created, but before extinction has been added, before continuum normalization, and before any emission lines have been added.
lines: list of dictionaries, giving information on each line to be added to the SED. NOTE that redshift, extinction, and normalization will not be applied to any lines specified here. Each line dictionary has the following parameters:
id: string or integer. Identifier given to the line. Not used internally.
name: string. Name of the line. Not used internally.
emission_or_absorption: string, line type. Currently, all lines are treated as emission lines.
center: float, central wavelength of the line, in microns.
width: float, FWHM of the line in km/s.
strength: float, line strength, definition depends on line type:
Emission Lines: line strength in erg/cm^2/s
Absorption Lines: central optical depth (once they are implemented).
profile: string, line profile, currently the only supported value is 'gaussian'
sed: dictionary, provides the parameters of the source continuum SED. Contains the following keys:
sed_type: string, defines the type of SED. Possible values are 'no_continuum', 'flat', 'powerlaw', 'blackbody', 'phoenix', 'hst_calspec', 'brown', and 'input'. Depending on the SED type chosen, other parameters may be needed.
no_continuum: takes no parameters1
flat: takes 'unit'1
powerlaw: takes 'unit' and 'index'1
blackbody: takes 'temp'1
phoenix: takes 'key' (if perform_calculation is run with webapp=True) or takes 'teff', 'log_g', and 'metallicity' (if perform_calculation is run with webapp=False)
hst_calspec: takes 'key'
brown: takes 'key', galaxy models based on Brown et al. (2014).
input: takes 'spectrum',
unit: string, either 'fnu' or 'flam'. Used by flat and power law spectra.
index: float, exponent of the power law. Used by power law spectra.
temp: float, temperature of the blackbody. Used by blackbody spectra.
key: string, the type of source to model. Used by phoenix, hst_calspec, and galaxies spectra. Valid values are shown below in the appendix.
t_eff: float, effective temperature of the phoenix model star, in K. Allowed range is 2000 to 70,000.
log_g: float, logarithm of the surface gravity of the phoenix model star, in cgs units. Allowed range is 0.0 to 5.5.
metallicity: float, logarithm of the metallicity of the phoenix model star, relative to solar metallicity. Allowed range is -4.0 to 0.5.
spectrum: list of 2 arrays, or ndarray. The wavelength (micron) and flux (mJy) arrays of the SED to use. In an ndarray, wavelength is the 0th index, and flux the 1st index.
normalization: dictionary defining the source brightness. Contains the following keys:
type: string, defines the type of normalization. Possible values are 'at_lambda', 'hst', 'jwst' 'photsys', and 'none'. Depending on the normalization type chosen, other parameters may be needed.
none takes no parameters.
hsttakes 'bandpass', 'norm_flux', and 'norm_fluxunit'
jwst takes 'bandpass', 'norm_flux', and 'norm_fluxunit'
photsys takes 'bandpass', 'norm_flux', and 'norm_fluxunit'
at_lambda takes 'norm_wave', 'norm_waveunit', 'norm_flux', and 'norm_fluxunit'
norm_wave: float, reference wavelength in units of 'norm_waveunit', used by 'at_lambda'.
norm_waveunit: string, specifies the wavelength units used for normalization, used by 'at_lambda'. Available values are 'm', 'nm', 'um' (micron), 'mm', 'micron', 'microns', 'angstrom'
norm_flux: float, reference flux value in units of 'norm_fluxunit', used by all normalization methods other than 'none'.
norm_fluxunit: string, specifies the flux units used for normalization. Used by all methods other than 'none'. Available values are 'flam', 'fnu', 'vegamag', 'abmag', 'mjy', 'ujy' (micro-Jansky), 'njy', 'jy'
bandpass: string, specifies the bandpass for 'hst', 'jwst', and 'photsys' normalizations. Possible values are shown in the appendix
extinction: dictionary defining the wavelength-dependent extinction between the source and the observer. Contains the following keys:
law: string, the extinction law being used. Values include seven models from Weingartner & Draine (2001) (3 generic Milky Way models: 'mw_rv_31', 'mw_rv_40', 'mw_rv_55'; 2 LMC models: 'lmc_avg' and 'lmc_2'; one SMC model: 'smc_bar', and the 'hd210121' model), and one Chapman (2009) model: 'chapman09'.
value: float, the extinction value, in units of 'unit'
unit: string, the units of the extinction value, either 'nh' for hydrogen column density or 'mag' for magnitudes.
bandpass: the bandpass in which the extinction is measured, only used if the unit is 'mag'.
Sample code creating a background spectrum using the JWST Background Tool (JBT)
Note that, in order to use the JWST backgrounds tool (JBT), it must be installed in your conda environment (i.e. by typing "pip install jwst_backgrounds" at the command line). For more information on the JBT, see the JBT documentation page.
Creating a scene with a custom galaxy spectrum and a foreground star
Creating a sample slitless spectrograph observation of a superimposed star and galaxy
Two figures are shown below. The first is a MIRI F560W image of the scene resulting from the above commands. The second is a set of three slitless spectra created with the MIRI P750L slitless spectrograph, one of each scene source individually, and a final observation of the combined scene. Note that the three separate spectra result from three separate Pandeia observations with the same instrument and detector settings, but different source lists. Note: The F560W image is partially saturated, and included mostly to provide an indication of the relative source locations on the detector.
Creating a source galaxy with a redshifted emission line
Appendices valid values for configuration dictionary
The following are valid values for configuration dictionaries:
sed_type = 'phoenix'
key may have the following values:
sed_type = 'hst_calspec'
key may have the following values:
sed_type = 'brown'
key may have the following values:
Values present in the web UI
Values that will work, but are not present in the web UI
type = 'hst'
bandpass may have the following values:
type = 'jwst'
bandpass may have the following values:
type = 'photsys'
bandpass may have the following values:
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