Atomic Processes in Gaseous NebulaeAndri ProzeskyMSc

Outline

Introduction Atomic ProcessesModelling NebulaeWhy is this New?Why is this Important?ResultsFuture Work

Introduction

Introduction

Atomic Processes - Radiative

Absorption Spontaneous emission Stimulated emission

Bound-bound processes

Photoionization Radiative recombination Stimulated recombination

Bound-free processes

Atomic Processes - Collisional

Collisional excitation Collisional de-excitation

Bound-bound

Collisional ionization Three-body

recombination

Bound-free

Modelling Nebulae

Probabilities of processes

Occupation numbers

Line fluxes

Modelling Nebulae

Thermodynamic equilibrium

Boltzmann distribution:

Modelling Nebulae

Real world Express occupation numbers ito departure

coefficients (bn values)

Nn in TEActual Nn

bn =

Modelling Nebulae

104 K104 cm-3

Te =Ne =

Modelling Nebulae

Specific focus – radio recombination lines (RRLs)

Why is this new?

Full quantum mechanical treatmentNewer atomic dataBetter computing power

Why is this new?

Calculations to higher nStimulated processes includedApplicable to very wide temp range

Why is this important?

New era in radio astronomy with higher sensitivity

Theory behind observations

Why is this important?

Check previous results

Bauman, Porter, Ferland & MacAdam (2005) ApJ 628 541

Results

Case A

Case B

Results

104 K104 cm-3

Te =Ne =

Results

104 K104 cm-3

20 pc

Te =Ne =

Rneb =

Future work

Include He and metalsRadiation fieldStructure of plasma

Future work

Effects of dustRadiative transfer

Thank you