European Space Astronomy Centre (ESAC)Villafranca del Castillo, SpainMatteo GuainazziIVOA InterOp meeting, 7 October 2005

Line Data Model Matteo Guainazzi*

Marie-Lise Dubernet**, Pedro Osuna*, Evelyne Roueff**, Jesus Salgado*

* ESA/VO - European Space Astronomy Centre (ESAC)** VO/France – LERMA, Observatoire de Paris*** VO/France – LUTh, Observatoire de Paris

European Space Astronomy Centre (ESAC)Villafranca del Castillo, SpainMatteo GuainazziIVOA InterOp meeting, 7 October 2005

Overall goals

Define VO standard to access atomic and molecular line databasesIntended to support laboratory data, as well as databases of observed lines at any wavelengthsOrganized around the concept of “Line”, defined as the result of a transition between two “Levels” (“initial”/”final”)

this concept encompasses both bound-bound, and free-bound transitions

“Levels” are characterized by a series of attributes, organized in classes:“Species” (the properties of the atom/molecule they belong)“QuantumState”/”QuantumNumber” (describing the quantum states of the initial/final level)

It shall be possible to describe processes which generate lines, or modify their observational properties in astrophysical plasmas

European Space Astronomy Centre (ESAC)Villafranca del Castillo, SpainMatteo GuainazziIVOA InterOp meeting, 7 October 2005

Document status and perspectives

Current version: 0.2 (26/9/2005) A discussion on several – albeit mostly minor – points is ongoing Short-term goal: Version 0.3 - agreed by mid-November - will be circulated to the DM group, as well as to atomic and molecular astrophysicists for comments Ultimate goal: achieve the status of a proposed recommendation by the next InterOp meetingin grey concepts

which are still under discussion

European Space Astronomy Centre (ESAC)Villafranca del Castillo, SpainMatteo GuainazziIVOA InterOp meeting, 7 October 2005

Structure

LineLevel

QuantumState

QuantumNumber

Process

Model Model Model

Species

Environment

Chemistry

European Space Astronomy Centre (ESAC)Villafranca del Castillo, SpainMatteo GuainazziIVOA InterOp meeting, 7 October 2005

Line

Scope: describe the overall properties of the observed line, and of its corresponding transitionAttributes:

“Wavelenght” (SEDCoord)Observational properties:

intensity/fluxsignificancebroadeningwavelength shift

Transition properties:Einstein coefficientsoscillator strengthstransition type

Spectral Data Model

European Space Astronomy Centre (ESAC)Villafranca del Castillo, SpainMatteo GuainazziIVOA InterOp meeting, 7 October 2005

Species

Scope: describe the properties of the atom/molecule/compound, where the transition generating the line occursAttributes:

identifiersatomic/molecular symbols/formula, atomic number, number of atoms (in a molecule)

general physical propertiespolarisability, first ionisation potential, ionisation state, formation enthalpy, permanent electric dipole moment, total mass, quadrupole moment

fundamental configurationDo we need a general “Chemistry” model to reconstruct molecule or compounds (formulae) from their elemental particles?

the model does not intrinsically require an explicit distinction between an atom and a molecule “class” so far

European Space Astronomy Centre (ESAC)Villafranca del Castillo, SpainMatteo GuainazziIVOA InterOp meeting, 7 October 2005

Level – QuantumState - QuantumNumber

Scope: describe the quantum state of the levels, between which the transition originating the line occursAttributes:

Physical properties:energy (with its origin) statistical weightlifetimequantum constants (Lande factor etc.)

Quantum state:normalized probabilitymolecular term symbolconfigurationparitysymmetriesquantum numbers

European Space Astronomy Centre (ESAC)Villafranca del Castillo, SpainMatteo GuainazziIVOA InterOp meeting, 7 October 2005

Examples of Quantum NumbersQuantumNumber.name = “j”QuantumNumber.type = “Total angular momentum”QuantumNumber.origin1 = “L”QuantumNumber.origin2 = “S”QuantumNumber.numeratorValue = 3QuantumNumber.denominatorValue = 2

QuantumNumber.name = “s”QuantumNumber.type = “Spin angular momentum”QuantumNumber.origin1 = UNDEFQuantumNumber.origin2 = UNDEFQuantumNumber.numeratorValue = 1QuantumNumber.denominatorValue = 2

Coupling of L and S

Value = 3/2

Pure state

Value = 1/2

A full list of “acceptable” quantum number will be published

European Space Astronomy Centre (ESAC)Villafranca del Castillo, SpainMatteo GuainazziIVOA InterOp meeting, 7 October 2005

Process/Environment

Scope: describe the physical process(es) which generates or modifies a line, and the properties of the astrophysical medium where it occursAttributes:

Process:Type/nameEach process is described by its own Model classExamples: “relativistic profile distortion”, “thermal”/”natural broadening”, “radiative recombination continua”

Environment:Thermodynamics (temperature, density, pressure, entropy, density)Optical depthMetallicityMass

European Space Astronomy Centre (ESAC)Villafranca del Castillo, SpainMatteo GuainazziIVOA InterOp meeting, 7 October 2005

User cases Radio astronomical spectroscopy of the hyperfine structure in N2H

+ (Caselli et

al. 1995) Radiative recombination continua in the XMM-Newton/RGS spectrum of

the Seyfert 2 galaxy NGC1068 (Kinkhabwala et al. 2002) ISO Line Database (see I.Barbarisi's talk, Application/14:30)