Multiwavelength spectroscopy of high accretion rate polars Axel Schwope Astrophysical Institute Potsdam Justus Vogel, Robert Schwarz (AIP) Fred Walter (SUNY) Vadim Burwitz (MPE) Klaus Reinsch (Göttingen)

Polars – 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 scenarios 3) particle heating hard X-ray supressed (low mass flow rate plus high B field) 1 2 Standard – stationary soft and hard X-rays balanced Filamentary – instationary soft X-ray excess (high mass flow rate and/or low magnetic field)

Issues for XMM/Chandra Temperature and density structure of accretion column (if there is one)  X-ray line diagnostic

Line diagnostics in AM Her (Girish et al 2007)

Issues for XMM/Chandra Temperature and density structure of accretion column (if there is one)  X-ray line diagnostic Structure of accretion regions  eclipsing systems

HU Aqr: fit to X-ray and UV-light curves (Schwope+01) Eclipse resolved Q ~ 3o l ~ 450 km h ~ 0.015 Rwd ~ 120 km

XMM-Newton observation of HU Aqr (May 17, 2002) Schwope et al 2004, ASP

HU Aqr: Simultaneous observations XMM & VLT(ULTRACAM) 16.5.2005 VLT-UT3 (ULTRACAM g) XMM EPIC pn Schwarz et al 2008, A&A

Issues for XMM/Chandra Temperature and density structure of accretion column (if there is one)  X-ray line diagnostic Extent of emission region  eclipsing systems Heating and cooling as a function of mass accretion rate  SED of bright systems

SEDs – hydro and particle picture Shock heating Specific mass flow rate (B, Mwd, geometry, ...) Particle heating Beuermann 2004 Fischer & Beuermann 2001

High accretion rate polars Duty cycle ~ 50% (cf. Ramsay et al 2004) The XMM-Newton conspiracy NONE of the ‚classical‘ bright polars was observed in a high accretion state XMM triggers (V834 Cen AO5, VV Pup AO6)

VV Pup – the soft X-ray machine Schwope et al 1995 Patterson et al 1984 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? MSSL polar survey Weak instationary accretion Thermal plasma ~4keV (Pandel et al 2005)

VV Pup SMARTS optical monitoring

Simultaneous optical-UV-X observation of VV Pup Oct 20, 2007

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

SED – low state . HST (Araujo-Betancor+05) XMM/OM (Pandel+05) VLT (Mason+07) .

High state, main pole: cyclotron = (bright – faint) kTcyc ~ 10 keV Fcyc ~ 2e-11 cgs

High state, bright phase X-ray spectrum bbody (30eV)+mekal(12keV) need warm absorber don‘t need abs, reflect (?)

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 SED FUSE EUVE ROSAT EPIC RGS EINSTEIN ROSAT & EUVE agree, EINSTEIN high Lx ruled out by FUSE Both poles in ROSAT brighter than in XMM epoch

VV Pup results Spectra (!) for low states and faint phases T evolution: Shock vs particle heating High state SED always dominated by soft X-rays at both poles  additonal blob heating Low state: No soft component observed

V834 Cen – multispectral data Jan 31, 2007

V834 Cen viewing geometry and multispectral light curves

V834 Cen – non-dip spectrum wabs*absori (bbody(25eV) + mekal_cool(<1keV) + mekal_hot(12keV)) need reflection

V834 Cen – SED kT (cyc)~ 10 keV Fcyc ~ 1e-11 cgs

V834 Cen – SED through high and low states

SED results Pole B (MG) F-bol cgs Fsoft / (Ftp + Fcyc) cgs 100% V834 Cen low state 22 2e-10 >5e-14 6 / 65 + 35 ? / VV P1 X R 31 5e-10 3e-10 4-20 / 17 + 83 7-10 / 30 + 70 VV P2 X R 56 <e-11 2e-12 <5 / 25 + 75 1-2 / 10 + 90 VV low ~5e-13 ? / 10 + 90

Spectral energy distribution: 2XMMp1312+1736 Vogel+08, astroph 0804

Conclusions and outlook SED fitting: relevance of multi-spectral data Evolution of spectral parameters for given pole Evolution of channels of energy release as a function of mass flow rate, B, Mwd and ? Further insight from phase-resolved X-ray spectral analysis And yes, we need more data and we do support XEUS (X-ray Doppler tomography)