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)