Modelling the high mass accretion rate spectra of GX 339-4

Mari Kolehmainen & Chris DoneDurham UniversityMaria Diaz Trigo, ESO

High Energy View of Accreting Objects: X-ray BinariesAgios Nikolaos, Crete

2010

High mass accretion rate spectra

• classical high/soft state▫ disc dominated▫ measure BH spin from disc

continuum

• very high/intermediate state▫ strong hard X-ray tail▫ measure BH spin from Fe-line

profile

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Beyond the RXTE energy band

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GX 339-4

3 keV

GX 339-4

• 5.8 < M< 15 M

D > 6 kpc 45°< i < 70°

• Loads of RXTE data (> 3 keV)

• Few XMM-Newton EPIC-pnBurst mode observations (> 0.7 keV)▫ not piled up!

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EPIC-pn Burst mode

• Time resolution 7μs• Timing mode 30μs (800 counts/s)• Pileup limit 60,000 counts/s

• Duty cycle 3 %• photon collecting time/readout time

• Extracted using SAS10

• includes CTI correction

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Burst mode observations of GX 339-4• joint EPIC-pn/RXTE

observations

• 2 disc dominated states• 2 soft intermediate states (SIMS)

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Burst mode observations of GX 339-4M = 10 M

D = 8 kpci = 60°

0156760101 (SIMS)

0410581201 (discy)

0410581301 (SIMS)

0410581701 (discy)

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Kolehmainen & Done (2010)

3 keV

• DISKBB• simplest multi-colour disc blackbody

• KERRBB• stress-free inner boundary condition, relativistic smearing

and the colour- temperature correction• BHSPEC• calculates radiative transfer

through each disc annuli• includes all the relativistic

corrections• assumes Rin=RISCO

Continuum fitting below 3 keV: Disc dominated state

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Continuum fitting below 3 keV: Disc dominated state• Disc model

▫ use this as seed photons for Comptonisation (convolved with Simpl (Steiner et al. 2009)) to make X-ray tail

• reflection of Comptonised continuum using ionised reflection models of Ross & Fabian

• relativistic smearing (kdblur)

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Continuum fitting below 3 keV: Disc dominated state

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• diskbb+reflection▫very steep

continuum to make disc broader Γ > 3

▫reflection fraction ~4

▫misses HEXTE

Continuum fitting below 3 keV: Disc dominated state

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• diskbb+reflection▫very steep

continuum to make disc broader Γ > 3

▫reflection fraction ~4

▫misses HEXTE

Continuum fitting below 3 keV: Disc dominated state

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• diskbb+CompTT+reflection▫Γ~2.4▫reflection

fraction~0.4▫extrapolates to

HEXTE

Continuum fitting below 3 keV: Disc dominated state

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• diskbb+CompTT+reflection▫Γ~2.4▫reflection

fraction~0.4▫extrapolates to

HEXTE

Continuum fitting below 3 keV: Disc dominated state

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• bhspec+reflection▫Γ~2.3▫reflection fraction ~0.9▫extrapolates to

HEXTE▫does not allow SIMS

fitting

Continuum fitting below 3 keV: Disc dominated state

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• bhspec+reflection▫Γ~2.3▫reflection fraction ~0.9▫extrapolates to

HEXTE▫does not allow SIMS

fitting

Continuum fitting past the disc dominated state: The model

• tbabs*((diskbb*simpl)+CompTT+kdblur*refxion*(simpl*diskbb))

• a major advantage comes from being able to fit with different mass accretion rates

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disc dominated

Continuum fitting past the disc dominated state: The model

• tbabs*((diskbb*simpl)+CompTT+kdblur*refxion*(simpl*diskbb))

• a major advantage comes from being able to fit with different mass accretion rates

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SIMS

The soft intermediate state (SIMS)

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Obsid 0410581301

Previously derived an upper limit of 0.9 for the spin in

GX 339-4 from continuum fitting of disc dominated RXTE

spectra

GX 339-4 widely studied in terms of Fe-line• burst mode spectrum gave a*= 0.935

(Miller et al. 2004; Reis et al. 2008)

The Fe-line and the BH spin

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The Fe-line and the BH spin

diskbb+po+reflection• disc, power law, ionised smeared

reflection• continuum modelled by ignoring

4−7 keV

Residuals show a broad iron line

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Obsid 0156760101

The Fe-line and the BH spin

diskbb+compTT+reflection• convolved disc, compTT,

ionised smeared reflection

Narrow line does not constrainBH spin

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Obsid 0156760101

Conclusions

• The XMM-Newton Burst mode can actually be used to make science ▫ can look at the disc below 3 keV even with the

brightest objects

• Real disc spectra are much broader than diskbb

• Changing the continuum model changes the shape of the iron line (and the BH spin)

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