Multiwavelength spectroscopy of high accretion rate polars

Multiwavelength spectroscopy of high accretion rate polars

Axel SchwopeAxel SchwopeAstrophysical Institute PotsdamAstrophysical Institute Potsdam

Justus Vogel, Robert Schwarz (AIP)Justus Vogel, Robert Schwarz (AIP)

Fred Walter (SUNY)Fred Walter (SUNY)

Vadim Burwitz (MPE)Vadim Burwitz (MPE)

Klaus Reinsch (Göttingen) Klaus Reinsch (Göttingen)

Polars – magnetic CVsPolars – magnetic CVs• main sequence secondary

• magnetic white dwarf

• accretion stream/curtain

• magnetic field (10 – 200 MG)

synchronous rotation

no disk

cyclotron cooling

~80 systems known

High/low states

Accretion scenariosAccretion scenarios

Standard – stationary soft and hard X-rays balanced

Filamentary – instationarysoft X-ray excess

(high mass flow rate and/orlow magnetic field)

1

3) particle heatinghard X-ray supressed(low mass flow rate plus high B field)

2

Issues for XMM/ChandraIssues for XMM/Chandra

I.I. Temperature and density structure of Temperature and density structure of accretion column (if there is one)accretion column (if there is one)

X-ray line diagnostic X-ray line diagnostic

Line diagnostics in AM Her(Girish et al 2007)

Line diagnostics in AM Her(Girish et al 2007)

Issues for XMM/ChandraIssues for XMM/Chandra

I.I. Temperature and density structure of Temperature and density structure of accretion column (if there is one)accretion column (if there is one)

X-ray line diagnostic X-ray line diagnostic

II.II. Structure of accretion regions Structure of accretion regions eclipsing systems eclipsing systems

HU Aqr: fit to X-ray and UV-light curves (Schwope+01)

HU Aqr: fit to X-ray and UV-light curves (Schwope+01)

~ 3o l ~ 450 km

h ~ 0.015 Rwd

~ 120 km

Eclipse resolved

XMM-Newton observation of HU Aqr (May 17, 2002)XMM-Newton observation of HU Aqr (May 17, 2002)

Schwope et al 2004, ASP

HU Aqr: Simultaneous observations XMM & VLT(ULTRACAM) 16.5.2005HU Aqr: Simultaneous observations XMM & VLT(ULTRACAM) 16.5.2005

I.I. VLT-UT3VLT-UT3(ULTRACAM g)(ULTRACAM g)

II.II. XMM EPIC pnXMM EPIC pn

Schwarz et al 2008, A&A

Issues for XMM/ChandraIssues for XMM/Chandra

I.I. Temperature and density structure of Temperature and density structure of accretion column (if there is one)accretion column (if there is one)

X-ray line diagnostic X-ray line diagnostic

II.II. Extent of emission region Extent of emission region eclipsing systems eclipsing systems

III.III. Heating and cooling as a function of mass Heating and cooling as a function of mass accretion rate accretion rate

SED of bright systems SED of bright systems

SEDs – hydro and particle picture

SEDs – hydro and particle picture

Beuermann 2004Fischer & Beuermann 2001

Specific mass flow rate(B, Mwd, geometry, ...)

Particle heating

Shock heating

High accretion rate polars High accretion rate polars

I.I. Duty cycle ~ 50% (cf. Ramsay et al 2004)Duty cycle ~ 50% (cf. Ramsay et al 2004)

II.II. The XMM-Newton conspiracyThe XMM-Newton conspiracyNONE of the ‚classical‘ bright polars was observed in a high NONE of the ‚classical‘ bright polars was observed in a high accretion stateaccretion state

III.III. XMM triggers (V834 Cen AO5, VV Pup AO6)XMM triggers (V834 Cen AO5, VV Pup AO6)

VV Pup – the soft X-ray machine

VV Pup – the soft X-ray machine

Patterson et al 1984

Schwope et al 1995

Porb = 100 min

Two-pole geometry

soft main pole

less soft secondary pole

spectral evolution through bright phase (shoulder)

VV Pup – the soft X-ray machine?

VV Pup – the soft X-ray machine?

MSSL polar survey

Weak instationary accretion

Thermal plasma ~4keV

(Pandel et al 2005)

VV PupSMARTS optical monitoring

VV PupSMARTS optical monitoring

Simultaneous optical-UV-Xobservation of VV Pup Oct 20, 2007

Simultaneous optical-UV-Xobservation of VV Pup Oct 20, 2007

VV Pup – multi-epoch optical and X-ray light curves

VV Pup – multi-epoch optical and X-ray light curves

SED – low stateSED – low state

HST (Araujo-Betancor+05)

XMM/OM (Pandel+05)

VLT (Mason+07)

.

High state, main pole: cyclotron = (bright – faint)

High state, main pole: cyclotron = (bright – faint)

kTcyc ~ 10 keV

Fcyc ~ 2e-11 cgs

High state, bright phaseX-ray spectrum

High state, bright phaseX-ray spectrum

bbody (30eV)+mekal(12keV)need warm absorberdon‘t need abs, reflect (?)

VV Pup – high & low state high-energy SED

VV Pup – high & low state high-energy SED

Main pole

XMM: kT ~ 12 keV, 4e-12 cgs

ROSAT/EUVE: ~ 8e-12 cgs

Second pole

XMM: kT ~ 4 keV, 4e-13 cgs

ROSAT/EUVE: ~ 2e-13 cgs

Low state

XMM: kT ~ 4 keV, 5e-14 cgs

ROSAT/EUVE: ---

VV Pup – high state SEDVV Pup – high state SED

FUSE

EUVE

ROSATEPIC

RGS

EINSTEIN

ROSAT & EUVE agree, EINSTEIN high Lx ruled out by FUSEBoth poles in ROSAT brighter than in XMM epoch

VV Pup resultsVV Pup results

I.I. Spectra (!) for low states and faint Spectra (!) for low states and faint phasesphases

II.II. T evolution: Shock vs particle heatingT evolution: Shock vs particle heating

III.III. High state SED always dominated by High state SED always dominated by soft X-rays at both poles soft X-rays at both poles additonal blob heating additonal blob heating

IV.IV. Low state: No soft component observedLow state: No soft component observed

V834 Cen – multispectral data Jan 31, 2007

V834 Cen – multispectral data Jan 31, 2007

V834 Cen viewing geometry and multispectral light

curves

V834 Cen viewing geometry and multispectral light

curves

V834 Cen – non-dip spectrumV834 Cen – non-dip spectrum

wabs*absori (bbody(25eV) + mekal_cool(<1keV) + mekal_hot(12keV))need reflection

V834 Cen – SEDV834 Cen – SED

kT (cyc)~ 10 keV

Fcyc ~ 1e-11 cgs

V834 Cen – SED through high and low states

V834 Cen – SED through high and low states

SED resultsSED results

PolePole BB(MG)(MG)

F-bolF-bolcgscgs

Fsoft / (Ftp + Fcyc)Fsoft / (Ftp + Fcyc)cgs 100%cgs 100%

V834 CenV834 Cenlow statelow state

2222 2e-10 2e-10 >5e-14>5e-14

6 / 65 + 356 / 65 + 35? / ? /

VV P1 XVV P1 X R R

3131 5e-105e-103e-103e-10

4-20 / 17 + 834-20 / 17 + 837-10 / 30 + 707-10 / 30 + 70

VV P2 X VV P2 X R R

5656 <e-11<e-112e-122e-12

<5 / 25 + 75<5 / 25 + 751-2 / 10 + 901-2 / 10 + 90

VV lowVV low 3131 ~5e-13~5e-13 ? / 10 + 90? / 10 + 90

Spectral energy distribution: 2XMMp1312+1736

Vogel+08, astroph 0804.3946

Spectral energy distribution: 2XMMp1312+1736

Vogel+08, astroph 0804.3946

Conclusions and outlookConclusions and outlook

I.I. SED fitting: relevance of multi-spectral dataSED fitting: relevance of multi-spectral data

II.II. Evolution of spectral parameters for given pole Evolution of spectral parameters for given pole

III.III. Evolution of channels of energy release as a function Evolution of channels of energy release as a function of mass flow rate, B, Mwd and ?of mass flow rate, B, Mwd and ?

IV.IV. Further insight from phase-resolved X-ray spectral Further insight from phase-resolved X-ray spectral analysis analysis

V.V. And yes, we need more data and we do support XEUS And yes, we need more data and we do support XEUS (X-ray Doppler tomography)(X-ray Doppler tomography)