12/30/10 Ab initio spectral simulations The n H T u plane Detailed - - PDF document

12/30/10 1 Ab initio spectral simulations

 Detailed microphysics  Energetic radiation &

particles interact with gas

 Ejected electrons heats,

excite & ionize gas

 Ionization drives

chemistry

 Kinetic temperature,

ionization, full spectrum, predicted

The nH – Tu plane

Θ

1 Ori

exciting stars Ionized gas Atomic gas Veil Molecular gas

100” BN 0.5 pc

A A B B OMC, 13CO To Earth Figure 8.4, Osterbrock & Ferland AGN3

Depth (cm)

1.5e+17 1.6e+17 1.7e+17 1.8e+17 1.9e+17 2.0e+17

molecular fractional

10-4 10-3 10-2 10-1 100

Temperature

100 1000 10000

• log fractional ionization

1 2 He0 He+ C+2 H2 C0 H+ H0 CH CO OH H2O H2O

Ferland, G.J., 2003, ARA&A, 41, 517

Carbon ionization along ray

Depth (cm)

1e+15 1e+16 1e+17 1e+18

Ion - molecular fraction

• 8
• 6
• 4
• 2

C+3 C0 C+ C+2 CO

Spectrum at half-H2 point

1.00E-02 1.00E-01 1.00E+00 1.00E+01 1.00E+02 1.00E+03 1.00E+04 1.00E-01 1.00E+00 1.00E+01 1.00E+02 1.00E+03

Wavelength (microns) νSν (erg cm-2 s-1)

12/30/10 2

Depth (cm)

1.5e+17 1.6e+17 1.7e+17 1.8e+17 1.9e+17 2.0e+17

molecular fractional

10-4 10-3 10-2 10-1 100

Temperature

100 1000 10000

• log fractional ionization

1 2 He0 He+ C+2 H2 C0 H+ H0 CH CO OH H2O H2O

Abel et al ApJS 161, 65 astro-ph 0506514

A holistic approach – the entire cloud AGN spectrum

• Databases used by Cloudy

 Databases used within Cloudy

– Fe II with ~103 levels, H2 with ~105 levels – Lamda molecular data base Schoeier+05 – Chemistry UMIST – Chianti ionic data base Dere+09 – Badnell RR & DR – Verner photoionization database with extensions – Kingdon charge transfer database with extensions – Ames PAH opacity database in progress

Our approach

 Many databases are needed  Use exactly the downloaded ascii files  So that updates will be trivial  This seldom works

12/30/10 3 Properties of a good database

 DRY – Don’t Repeat Yourself  Robustly machine readable

– Not fixed format, use field delimiters

 Data provenance easily traced  Data verified upon readin  Data easily updated

– Computers are cheap and do exactly what we tell them to – People are expensive and make mistakes – Data should from the published paper