Models¶

TARDIS requires a model of the homologously expanding ejecta in order to run a simulation (see Model of Supernova Domain). A model will include information like the velocity shell structure, abundances, density, etc. TARDIS offers two ways of specifying the model: either directly in the configuration YAML file or separately in a model.csvy file. See here for an explanation of the CSVY file format and here for a link to the csvy_model schema.

Note

We highly recommend using the cleaner CSVY format.

CSVY Model
- Example CSVY Model
Model Configuration
Structure, Density, and Abundance
Tutorials
Model Converters

CSVY Model ¶

TARDIS allows users to use a CSVY file to input information about the model:

type	object
properties
name	name of the model being run
	type	string
model_density_time_0	Initial time for the density in the model
	type	quantity
model_isotope_time_0	Initial time for isotope decay. Set to 0 for no isotopes.
	type	quantity
description	description of the model being run
	type	string
tardis_model_config_version	Version of the configuration file
	type	string
datatype	fields found in csv part of csvy file
	type	object
	properties
	fields	type	array
	additionalProperties	False
v_inner_boundary	velocity of the inner boundary
	type	quantity
v_outer_boundary	velocity of the outer boundary of the last shell
	type	quantity
velocity	type	object
	properties
	start	type	quantity
	stop	type	quantity
	num	type	number
		multipleOf	1.0
density	oneOf	#/definitions/density/branch85_w7
		#/definitions/density/exponential
		#/definitions/density/power_law
		#/definitions/density/uniform
abundance	#/definitions/abundance/uniform
additionalProperties	False
definitions
density
abundance

The TARDIS YAML delimiter for CSVY files is ---. This means that each CSVY model file has the following structure: The first line of the file is the YAML delimiter, followed by the YAML portion of the CSVY model. A line consisting of only the YAML delimiter separates the YAML portion of the CSVY file from the CSV part. The YAML part of the CSVY file is for setting model parameters like v_inner_boundary or model_density_time_0, while the CSV part of the file is for setting profiles of physical parameters of the model (e.g. abundances, radiative temperature, dilution factor, etc). If you use the CSVY model, then you will need to specify the path to the CSVY model file in the main TARDIS configuration file.

Example CSVY Model ¶

We provide an example CSVY model file:

---
name: csvy_full
model_density_time_0: 1 day
model_isotope_time_0: 0 day
description: Example csvy config file for TARDIS.
tardis_model_config_version: v1.0
datatype:
  fields:
    -  name: velocity
       unit: km/s
       desc: velocities of shell outer bounderies.
    -  name: density
       unit: g/cm^3
       desc: density of shell.
    -  name: t_rad
       unit: K
       desc: radiative temperature.
    -  name: H
       desc: fractional H abundance
    -  name: He
       desc: fractional He abundance
    -  name: Ni56
       desc: fractional Ni56 abundance

v_inner_boundary: 9000 km/s
v_outer_boundary: 12000 km/s
---
velocity,density,t_rad,H,He,Ni56
9000, 5e-10, 7000, 1.0, 1.0, 1.0
10500, 2.0e-10, 7000, 0.0, 0.99, 0.01
12000, 9e-11, 7000, 0.4, 0.58, 0.02

Model Configuration ¶

Although we strongly recommend using the CSVY Model, TARDIS also allows the user to define structure and abundance profiles in separate files and reference these files directly in the main TARDIS configuration file:

type	object
properties
structure	oneOf	Specific Structure
		File Structure
abundances	oneOf	File Abundance
		Uniform Abundance
additionalProperties	False

For an example of this in use, see Tardis Example Configuration.

Structure, Density, and Abundance ¶

Structure ¶

All types of structure definitions have two keywords in common: v_inner_boundary and v_outer_boundary.

In the structure section, one can specify a file section containing a type parameter (currently only artis is supported``) and a name parameter giving a path top a file.

If one doesn’t specify a file section, the code requires two sections (velocities and densities) and a parameter no_of_shells. no_of_shells is the requested number of shells for a model. The velocity section requires a type. Currently, only linear is supported.

File Structure ¶

type	object
properties
type	enum	file
filename	file name (with path) to structure model
	type	string
filetype	file type
	type	string
	enum	simple_ascii, artis, cmfgen_model
v_inner_boundary	location of the inner boundary chosen from the model
	type	quantity
	default	-1 km/s
v_outer_boundary	location of the inner boundary chosen from the model
	type	quantity
	default	-1 km/s
additionalProperties	False

Specific Structure ¶

type	object
properties
type	enum	specific
velocity	description of the boundaries of the shells
	type	object
	properties
	start	type	quantity
	stop	type	quantity
	num	type	number
		multipleOf	1.0
density	oneOf	Branch85_w7 Density
		Exponential Density
		Power_law Density
		Uniform Density
additionalProperties	False

Density ¶

In the densities section the type parameter again decides on the parameters. The type uniform only needs a value parameter with a density compatible quantity. The type branch85_w7 uses a seven-order polynomial fit to the W7 model and is parametrised by time since explosion. The parameters time_0 and density_coefficient are set to sensible defaults and should not be changed.

Branch85_w7 Density ¶

type	object
properties
type	enum	branch85_w7
w7_time_0	This needs no change - DO NOT TOUCH
	type	quantity
	default	0.000231481 day
w7_rho_0	This needs no change - DO NOT TOUCH
	type	quantity
	default	3e29 g/cm^3
w7_v_0	This needs no change - DO NOT TOUCH
	type	quantity
	default	1 km/s
additionalProperties	False

Exponential Density ¶

type	object
properties
type	enum	exponential
time_0	Time at which the pure model densities are right
	type	quantity
rho_0	density at time_0
	type	quantity
v_0	at what velocity the density rho_0 applies
	type	quantity
additionalProperties	False

Using an exponential density profile

Power_law Density ¶

type	object
properties
type	enum	power_law
time_0	Time at which the pure model densities are right
	type	quantity
rho_0	density at time_0
	type	quantity
v_0	at what velocity the density rho_0 applies
	type	quantity
exponent	exponent for exponential density profile
	type	number
additionalProperties	False

Using a power law density profile

Uniform Density ¶

type	object
properties
type	enum	uniform
time_0	Time at which the pure model densities are right
	type	quantity
value	value for uniform density
	type	quantity
additionalProperties	False

Custom Density ¶

TARDIS also allows for a custom density profile:

Using a custom density profile

Abundance ¶

The abundance section has a possible file parameter with type (currently only artis is allowed) and a name parameter giving a path to a file containing the abundance information.

Warning

In contrast to the structure section, the abundance section will not ignore abundances set in the rest of the section but merely will overwrite the abundances given in the file section.

The rest of the section can be used to configure uniform abundances for all shells, by giving the atom name and a relative abundance fraction. If it does not add up to 1., TARDIS will warn — but normalize the numbers.

File Abundance ¶

type	object
properties
type	enum	file
filetype	type of abundance file to read in
	type	string
filename	filename
	type	string
additionalProperties	False

Using a custom stratified composition

Uniform Abundance ¶

type	object
properties
type	enum	uniform
additionalProperties	type	number
	maximum	1
	minimum	0

Using a uniform composition

Tutorials ¶

How to run TARDIS with a custom ejecta model

Model Converters ¶

There are a variety of formats for models from other codes (both hydro and radiative transfer) that can be converted to TARDIS input files. Here we aim to provide converters for the most commonly used file formats.