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

12/30/10 Ab initio spectral simulations The n H – T u plane  Detailed microphysics  Energetic radiation & particles interact with gas  Ejected electrons heats, excite & ionize gas  Ionization drives chemistry  Kinetic temperature, ionization, full spectrum, predicted 10000 B OMC, 13 CO Temperature 1000 100 0 - log fractional ionization A 1 C +2 He 0 H + 0.5 pc He + 2 BN C 0 H 0 Molecular gas 100” Atomic gas 10 0 CO molecular fractional B 10 -1 H 2 H 2 O Ionized gas Θ 1 Ori 10 -2 CH exciting stars 10 -3 OH A 10 -4 H 2 O Veil 1.5e+17 1.6e+17 1.7e+17 1.8e+17 1.9e+17 2.0e+17 Depth (cm) To Earth Ferland, G.J., 2003, ARA&A, 41, 517 Figure 8.4, Osterbrock & Ferland AGN3 Carbon ionization along ray Spectrum at half-H 2 point 1.00E+04 0 C +2 1.00E+03 CO C + Ion - molecular fraction ν S ν (erg cm -2 s -1 ) -2 1.00E+02 C +3 1.00E+01 -4 1.00E+00 C 0 -6 1.00E-01 -8 1.00E-02 1e+15 1e+16 1e+17 1e+18 1.00E-01 1.00E+00 1.00E+01 1.00E+02 1.00E+03 Depth (cm) Wavelength (microns) 1

12/30/10 10000 Temperature 1000 A holistic approach – the entire cloud 100 0 - log fractional ionization 1 C +2 He 0 H + He + 2 H 0 C 0 10 0 CO molecular fractional 10 -1 H 2 H 2 O 10 -2 CH OH 10 -3 10 -4 H 2 O 1.5e+17 1.6e+17 1.7e+17 1.8e+17 1.9e+17 2.0e+17 Depth (cm) Abel et al ApJS 161, 65 astro-ph 0506514 �� � �� �� ������������� � ��������� �� � ��� AGN spectrum �� � � �� ��� � ��� � �� �� � ���� �� �� �� �� ������������� � ��������� ��� ���� � �� ��� �� � � �� ��� ���� � �� �� �� �� �� � �� ��� ���� �� � ���� �� �� �������������������� �� �� ���� ��� � �� ��� �������������������� Databases used by Cloudy Our approach  Databases used within Cloudy  Many databases are needed – Fe II with ~10 3 levels, H 2 with ~10 5 levels  Use exactly the downloaded ascii files – Lamda molecular data base Schoeier+05  So that updates will be trivial – Chemistry UMIST – Chianti ionic data base Dere+09 – Badnell RR & DR  This seldom works – Verner photoionization database with extensions – Kingdon charge transfer database with extensions – Ames PAH opacity database in progress 2

12/30/10 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 3