X-ray spectra modeling for accretion plasma of magnetic white dwarfs ESAC Summer Alumni Trainee Meeting 2010 X-ray spectra modeling for accretion plasma of magnetic white dwarfs Speaker: Alexander Kolodzig Origin: Humboldt-Universität, Berlin, Germany Institute: AIP (Astrophysical Institute Potsdam), Potsdam, Germany Tutor: Axel Schwope Date: 02.07.2010 7 month on the work excitement of work - brief glance of my work Background Picture Credits : Mark A. Garlick

Magnetic Cataclysmic Variable Terminology: accreting magnetic white dwarfs = MCV alternative names: Polar “AM Herculis” - type Picture Credits : Mark A. Garlick 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Picture Credits : Mark A. Garlick MCV Roche-lobe overflow Compact Binary: mass ratio: 0.1 - 0.5 MSec./MWD period: 80 min - 8.0 hours separation: 0.5 - 2.0 R accretion rate: 10-12 - 10-8 M /yr late-type main sequence star (Secondary) accretion stream no accretion disc White Dwarf (Primary) Picture Credits : Mark A. Garlick 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Picture Credits : Mark A. Garlick MCV White Dwarf (WD): strong magnetic field (B ≥ 10MG) synchronized rotation: PSpin = POrbit accretion onto magnetic pole(s) stagnation region late-type main sequence star (Secondary) accretion stream partially ionized magnetic field lines White Dwarf (Primary) Shock Picture Credits : Mark A. Garlick 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Example X-ray spectrum (XMM-Newton: EPIC pn) one temperature blackbody model Continuum: one temperature plasma emission model (XSPEC: “MEKAL”) Object: AM Herculis main work stage: creating consistent multi-temperature model 5-6 EPIC pn spectra of AM Hercules Transition to next slide: to understand the x-ray emission better, we need to understand how the radiation is really produced. Bad fit: for demonstration purposes only! Credits: A. Schwope & J. Vogel 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Simple accretion scenario 1994 vanTeeseling - X-ray irradiation of white dwarf atmospheres: The soft X-ray spectrum of AM Herc http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1994A%26A...281..119V Iris Traulsen – Diss., page: 13: Column accretion onto a magnetic white dwarf. In this simplified view, the material reaches the surface of the white dwarf along the magnetic field lines in a nearly radial symmetric accretion column. In the flow below the shock, it decelerates and cools. Adapted from van Teeseling et al. (1994). TMax > 107 K Illustration adapted from Teeseling et al. 1994 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

hydrodynamic equations Post-shock region hs << RWD h = 0 h = hs h - geometrical height [cm] Fischer & Beuermann (2001) 1D stationary two-particle-fluid hydrodynamic equations + frequency & angle-dependent radiative transfer x - column density [g/cm2] dx = - dh x = 0 x = xs Shock g = const. B = const. T1, 1 T2, 2 T3, 3 … Tn-2, n-2 Tn-1, n-1 Tn, n e- Ion - Bremsstrahlung (optical thin) - Cyclotron Radiation (optical thick) model -> radiation-hydrodynamics one-dimensional (Width >> hs) -> pill-box shape - stationary (no time dependence) -> mean properties (no fluctuation) infinite plane-parallel layers cooling flows WD surface 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

T +  Distributions 3 main physical parameters: MWD – White Dwarf Mass B – Magnetic Field of the WD MFD – Mass Flow Density (accretion rate per unite area) Shock - Height Shock WD surface 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Magnetic Field Variation Cyclotron Radiation more efficient -> faster plasma cooling -> lower Temperature -> lower Shock Height -> higher Volume Density -> different Spectrum Shock WD surface 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Layer + Column Spectra X-ray continuum: Bremsstrahlung TODO: thicker lines of the layer: Column: 8, Layer: 4 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Various Column Spectra TODO: MFD: 100 -> 1.0 ; same scale as Slide before: [10^-6,10^+3] 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Example X-ray spectrum (XMM-Newton: EPIC pn) one temperature blackbody model Continuum: one temperature plasma emission model (MEKAL) Object: AM Herculis emission lines 5-6 EPIC pn spectra of AM Hercules Credits: A. Schwope & J. Vogel 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Example X-ray spectrum (CHANDRA: HETG - HEG) Object: AM Herculis Fe XXV (Helium-like Iron) Fe XXVI (Hydrogen-like Iron) Reprocessed X-ray Flux [Counts /(sA)] 5-6 EPIC pn spectra of AM Hercules Transition to next slide: to understand the x-ray emission better, we need to understand how the radiation is really produced. Credits: Girish et al. 2007 Wavelength  [Angstroem] 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Synthetic X-ray spectra for AM Herculis Fe XXVI (Hydrogen-like Iron) Fe XXV (Helium-like Iron) - thermal broadening - no bulk velocity broadening -> Phase dependent - no gravitational redshift - no absorption TODO: Labeling of the lines!!!, change Title to: „AM Herculis – Iron Lines“ Explain: no plasma bulk velocity-shift in layer -> no broadening of the total-line (column) ->Phase dependent - Effective Area was calculated as a mean of HEG between 1,7 and 2,0 Angstroem Tools: XSPEC with APEC-Model 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Ionization Ratio with Iron TODO: thicker lines! include Ion.Ratio of Column! Shock WD surface Tools: CHIANTI Database 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Ionization Ratio + T Shock WD surface TODO: thicker lines! include Ion.Ratio and Mean(T) (weighted by dH) of Column ! Shock WD surface Tools: CHIANTI Database 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

next work stages further emission line analysis bulk velocity broadening vs. phase gravitational redshift further consistency checks testing Multi-T-Model with real data Animation of a MCV: 17sec 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Thank You For Your Attention! Contributions or Questions? e-mail: alex_kolo@gmx.de

Background - Slides

Picture Credits : Mark A. Garlick MCV Secondary: solar like star hydrogen plasma ball hydrogen fusion with Tcore ~ 107 K PGrav ~ PGas  T low mass: M = 0.1 - 0.5 M long lifetime: > t ~ 1010 years low TSurface ~ 3500 K Density ~ 10 g/cm3 late-type main sequence star (Secondary) Picture Credits : Mark A. Garlick 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Picture Credits : Mark A. Garlick MCV White Dwarf (Primary): remnant of a solar like star degenerated electron gas PGrav ~ PDeg   (No  T) Density > 105 g/cm3 MWD = 0.4 - 1.0 M , Peak at 0.6 M RWD ~ 1.5 M elements: no H, mainly C & O TSurface ~ 104 K White Dwarf (Primary) Picture Credits : Mark A. Garlick 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

X-ray spectrum hard x-ray: plasma emission soft x-ray: bremsstrahlung from the post-shock region thermal plasma emission fit (“MEKAL”-Model) soft x-ray: reprocessed emission from the accretion region blackbody fit fits are one-temperature-models what does this temperature mean? übergang zur nächsten Folie: to understand the x-ray emission better, we need to understand how the radiation is really producced. 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Theory hydrodynamic equations: radiative transfer: two-fluid (ions and electrons separately) connected by Coulomb interaction conversation of mass, momentum and energy electron gas heated by Ekin of the ions electron gas cooled by radiation radiative transfer: frequency and angle-dependent transfer cyclotron absorption, free-free absorption, electron scattering, no Compton scattering stationary and one-dimensional 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

MFD Variation Shock WD surface Credits: Fischer & Beuermann 2001 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

MFD Variation Shock WD surface Credits: Fischer & Beuermann 2001 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

WD Mass Variation Shock WD surface Credits: Fischer & Beuermann 2001 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Electron Temperature Shock WD surface 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Ion Velocity Shock WD surface Credits: Fischer & Beuermann 2001 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Ion Velocity Density: r(x)  1/v(x) Shock WD surface 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Bremsstrahlung Spectrum MWD = 0.6 M , B = 30 MG cyclotron radiation XMM-Newton Mass Flow Density [g/(scm2)] 10-1 100 10+1 10+2 d = 10 pc D = 108 cm Credits: Fischer & Beuermann 2001 IR optical UV EUV X-ray 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Spectral Energy Distribution XMM-Newton Optical – UV: accretion stream (interstellar absorption) Soft X-ray: reprocessed component (interstellar absorption) IR – optical: Secondary Star 1999 Beuermann - Magnetic cataclysmic variables: the state of the art after ROSAT http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999hxra.conf..410B&db_key=AST&link_type=ABSTRACT&high=4b65857b4c31468 Iris Traulsen – Diss., page: 17: Figure 2.6: Spectral energy distribution of AM Her. The dominant components are cyclotron emission in the infrared and optical, UV flux from the heated white-dwarf surface and from the accretion stream (IUE data), a soft X-ray quasi-black body arising from the accretion region (ROSAT data of April 1991), and hard X-ray emission produced in the accretion column (HEAO-1 data). The unabsorbed black body model flux corresponding to the soft X-ray component is marked as a dashed line in addition. From Beuermann (1999). Hard X-ray: bremsstrahlung IR – UV: Cyclotron radiation Credits: Beuermann 1999 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Picture Credits : Mark A. Garlick Origin of radiation who we see the object? -> due to its radiation. Picture Credits : Mark A. Garlick 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

SKIP: to complicated to explain, important for observers, M_WD-Estimation TODO: re-plot with CHIANTI-Data, MFD: 1.0 and M_WD- Variation! 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

Fe XXVI Hydrogen-like Iron Fe XXV Helium-like Iron SKIP: to much to explain Tools: XSPEC with APEC-Model and thermal broadening 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig

SKIP: better, to show EW-Dependency on B,MFD and M_WD but this would be to complicated TODO: inluced: total EW Shock WD surface Tools: CHIANTI-Database 02.07.2010 X-ray spectra modeling for accretion plasma of MCVs - Alexander Kolodzig