Photoionization Modeling: the K Lines and Edges of Iron P. Palmeri (UMH-Belgium) T. Kallman (GSFC/NASA-USA) C. Mendoza & M. Bautista (IVIC-Venezuela) J. Krolik (JHU-USA)

Plan Introduction Atomic Data Photoionized Plasma Modeling Conclusions

Introduction Iron K lines are observed in (almost) all X-ray sources First reported in rocket observations of the supernova remnant Cas A Serlemitsos, et al, 1973

Introduction Appear in a relatively unconfused region Emitted efficiently over wide range of temperatures and ionization states Relativistically broaden and red-shifted lines observed in galactic black hole candidates Tanaka et al., 1996

Introduction RXTE EXOSAT ASCAXMM Chandra Astro-E2 Compton 1000 km/s 300 km/s The world of X-ray observatory is changing:

Atomic Data Motivation: they were scarce and not sufficiently accurate especially for the M- shell ions (Fe I-XVII) Methods: standard atomic codes, i.e. AUTOSTRUCTURE (Badnell), HFR (Cowan) & BPRM (IP/RmaX Projects)

Atomic Data L-shell ions (Fe XVIII-XXV) CI: {2s,2p} N +[1s]{2s,2p} N+1 +up to double excitations to M-shell Semi-empirical corrections: compilation of Shirai et al (2000) M-shell ions (Fe I-XVII) Focus on K-vacancy states produced by removing a 1s electron from the ground configuration No experimental energies  Ab initio calculations Few experimental data (wavelengths): Fe X & solid state

Core Relaxation Effects Electrons in K-vacancy & valence configurations see radically different potentials  different orbitals for initial & final states of inner-shell transitions  affects level energies, wavelengths & rates !!! -increase radiative rates by ~5- 10% -increase KLL rates by ~10% -no systematic effect on KLM rates -decrease KMM rates by ~10%

Damping Effect Resonances before K-edge Spectator channels (Damping channels) Participator channels

Damping Effect: Photoabsorption Fe XVIIFe XXIII With damping Without damping

Damping Effect: Electron Impact Without damping With damping Fe XIX 2p 4 3 P 2  [1s]2p 5 3 P o 2 [1s]2p 5 3 P o 1 [1s]2p 5 3 P o 0

Line Energy vs. Ionization Stage Blue=Makishima Black=these studies Line moves to red near Fe IX Complicated K line structure

Edge Energy vs. Ionization Stage In first row ions, ground level is split by various valence configurations Blue=Makishima Black=these studies In 2nd and 3rd row ions, Splitting is smaller, Results differ significantly From previous

K  /K  ratio vs. Ionization Stage MCDF Auto-S HFR Kaastra-Mewe Jacobs- Rosznyai experiment  K  /K  ratio is a potential diagnostic of ionization

Fluorescence Yield vs. Ion. Stage Auto-S HFR Jacobs-Rosznyai Kaastra-Mewe Experiment

Photoionized Plasma Modeling With XSTAR Photoionization of a gas by intense external X-ray source (dominant) Other processes affecting ionization, excitation & temperature are in equilibrium  Local conditions (ionization fractions, temperature, opacity) parameterized by  =Ionization parameter  =4  Ionizing flux/gas density

Photoionized Plasma Modeling: Atomic Processes Each ion has ~3-30 K- vacancy levels which can be populated by photoionization ~4-100 K lines per ion considered in our treatment

Ionization Balance & Temperature Ionization balance temperature  =Ionization parameter=4  Ionizing flux/gas density 10 4 <T<10 8 K

Line Emissivity vs.  Emissivity j~  n 2

Line Emissivity vs. density Log  =2

Line Emissivity vs. density (continued) Log(n)=12 Log(n)=16

Line Emissivity vs. Optical Depth Multiplier  Lines can be suppressed by Auger destruction

Line Emissivity vs. Column Density 1/N decrease marks the Breakdown of the optically thin approximation Shift of ionization from high to low will be detectable in reprocessed spectrum Emissivity averaged over constant density slab with log(  )=2

Simulated Spectra XMM Epic PNAstro-E XRS Assuming log(  )=2, log(N)=23, 100 mcrab source, tobs= 100 ksec

Conclusions Structure of Iron K shell is more complicated than has been previously appreciated, & care is needed to accurately compute useful quantities There is a shortage of experimental data needed for accurate spectral modeling especially in intermediate & low ionization stages Converging series of damped resonances act to smear absorption edges Emission lines contain structure which has diagnostic value, even for low ionization gas