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Magnetic CVs in the XMM-Newton Era: the Intermediate Polars

This study explores the evolutionary link between Polars and IPs and the role of MCVs in the population of Galactic X-ray sources, using results from XMM-Newton. It investigates questions about the evolution of IPs towards synchronism and the magnetic field strengths in IPs.

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Magnetic CVs in the XMM-Newton Era: the Intermediate Polars

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  1. MagneticCVs in the XMM-Newton Era: the Intermediate PolarsD.de Martino INAF-Osservatorio Astronomico di Capodimonte Napoli & G.Anzolin, J.-M.Bonnet-Bidaud, M.Falanga, B.Gaensicke, F.Haberl, N.Masetti, G.Matt, M.Mouchet, K.Mukai

  2. Outline Open questions: • Evolutionary link betweenPolars and IPs • RoleofMCVs in PopulationofGalacticX-raySources • Roleoffundamentalparameters in accretion and emissionproperties Results from XMM-Newton: • Increased IP membership • New X-ray properties: commonalities with Polars

  3. Questions on MCV Evolution MCVs ~20-25% of all CVs vs MWDs~10% of all WDs RK v.7.10 (2008) ~50% ~40%

  4. Candidates increased by 50% in last 4yrs (see Koji Mukai’s IP Web Site) MCV Class Census:PolarsIPs Pre-Rosat 18 (60%) 12 (40%) Post-Rosat 55 (70%) 25 (30%) Today 94 (54%) 78 (46%) QUESTION • Do IPs evolve towardssynchronism? • Do IPsharbourlower B fieldWDs? ~70% ~80%

  5. What about B field strengths in IPs? Most IPs lie below synchronization line On average lower B field systems that may evolve towards synchronism SystematicSurvey in Polarized light stillmissing! • Polarimetric UBVRI surveyrecentlystarted @ NOT (Katajainenet al. 2007; Butterset al. 2009) • Spectropolarimetriy @ ESO/VLT attemptedbutlargeoversubscription! Polars: Beuermann (2000) IPS: Butters et al. 2009 V405 Aur PQ Gem V2400 Oph RXJ2133 • Polars ROLE OF SALT TELESCOPE ! BG CMi WGA1958 RXJ1730 V1223 Sgr

  6. Do IPs evolve towards synchronism? Wide range of asynchronisms: - Clustering close to Pspin/Porb=0.1 but new optical candidates at high & low degree of asynchronism - 50% of the class still to be confirmed in the X-rays! X-RAY FOLLOW-UPS ON GOING! Norton et al. (2004,2008) propose IPs at Porb>3hrs with: • B ≥10 MG will evolve intoPolars • B≤10MG evolve intounobservablelow-fieldPolars or B fieldre-emergeswhenMdotdecreases. • Tokeepspin-equilibriumPspinincreaseswhilePorbdecreases -> short PorbIPsshouldbeweaklydesynchronized  Confirmed O Candidates X This work XMM-Newton

  7. HARD X-RAY MCVs HARD X-RAY SURVEYS ARE CHANGING THE VIEW! INTEGRAL ISGRI: 421 sources (~5% are CVs) SWIFT/BAT: 450 sources (~6% are CVs)

  8. Common characteristics of hard X-ray CVs? INTEGRAL-ROSAT COLOR DIAGRAM: Hard spectra with wide range of absorption 25 INTEGRAL CVs with ROSAT counterpart MostRXTE ,INTEGRAL & SWIFTdetectedCVs are MCVs (Revnistevet al. 2004; Barlowet al. 2006; Bonnet-Bidaudet al.2007; Mukaiet al.2007; Bodagheeet al. 2007; Shafteret al. 2008, seealso Potter et al. Poster yesterday…….) MAGNETISM & ASYNCHRONISM SEEM TO BE COMMON CHARACTERISTCS OF HARD X-RAY CVs ! × Dwarf Nova ● IP Candidates ○ Confirmed IPs ∆ Confirmed Polars ∆ Asynchr. Polars ▲ Candidate Polar ● ● ● ● ● Confirmed IPs with XMM-Newton (Haberl et al. 2002; Staude et al. 2006; de Martino et al. 2006,2008; Anzolin et al. 2009)

  9. RoleofMCVs in GalacticPopulations? CHANDRA SurveyofGalactic Center (Munoet al. 2003;2004; Ruiteret al 2005): - 1500 over 2000 FaintSources: Lx < 1031 – 1033 erg/s - Hard spectra: kT > 8keV & Fe H-like and He-likeemissions - Affectedbylocalabsorption - Variable: Periods 300sec – 4.5hrs IPsproposedtobedominantpopulation IPs a stillhiddenpopulationofXRBs? RXTE & INTEGRAL surveysofMilkyWay (Sazonovet al. 2006; Revnivtsevet al. 2006, 2008): • XLF [2-10keV] at L<1034erg/s fromCoronal (65%) and CVs (35%) • XLF ofCVs [2-12keV] similarto XLF[16-60keV] GalacticRidgeemission at E>20keV dominatedbyMCVs Seealso poster on ChandraSurveyofGalacticBulgeby Torres et al. (Tuesday)

  10. RoleofXMM-Newton • Uninterruptedobservationsoffaintsources : - Securemembershipidentification - Accretion mode diagnostic :   Disc  -   Direct (no disc) accretion ,-,  Disc overflow (Hybrid) XMM-Newtonobserved 20 IPs : • Confirmed IP status for 11 candidates! • Providednewhints in emissionproperties • Energy dependentX-Ray/UV/Opticalpulses: - Geometry and magneticfieldcomplexity - SitesofPrimary & Reprocessedradiation - Absorptioneffects • X-Ray spectra: - Accretion region diagnostic: Pre-Shock, Post-Shock, WD irradiation

  11. X-ray Periodicities Complexities in Energy dependent X-Ray Power Spectra ω-Ω ω ω One Pole Hybrid (Anzolin et al. 2008) One Pole disc-fed (de Martino et al. 2005)

  12. X-ray Periodicities Complexities in Energy dependent X-Ray Power Spectra ω-Ω ω ω 2ω 3ω Two Poles disc-fed (de Martino et al. 2008) Two Pole Hybrid (de Martino et al. 2006)

  13. X-ray Pulses Energy dependent structured pulsations SeealsoKojiMukai’s Poster #87 Two hard & Soft Poles Stronger Soft Pole Primary hard & soft Pole + Secondary soft Pole One hard Pole

  14. X-ray Spectral Properties Starting from the simplest case of HT Cam (de Martino et al. 2005) Multi-temperature post-shock flow :EM(T) ≈(T/Tmax)α -He-like OVII triplet: no forbidden line -> high density limit ne> 5x1012cm-3 - OVII/OVIII ratio -> kTmin=0.3keV - V(OVIII)1000km/s-> Vshock≈Vff/4 - kTmax=20keV; α=0.7 Az=0.6 - Absorption negligible (de Martino et al. 2005,A&A)

  15. X-ray Spectral Properties Complexities at soft energies UU Col a Soft ROSAT IP Two temperatures:kT hot=11 keV kT cool=0.18 keV Az=0.4 Black-Body:kTbb=50eV Partial(51%) Dense Absorber:1.0x1023cm-2 Strong lines OVIII, OVII OVII/OVIII ratio -> kT=0.2 keV (de Martino et al. 2006, A&A) Multi-temperature plasma often unable to represent spectra

  16. X-ray Spectral Properties XMM-Newtonfindsnew SOFT X-RAY IPs RXJ0704+2625 & RXJ1803+4012 Multi-temperatures:kTmax~30 keV Black-Body:kTbb=95eV Partial(40%) Dense Absorber:3x1023cm-2 (Anzolinet al. 2008) One temperature:kT hot > 40 keV Black-Body:kTbb=84eV EW (6.4keV) = 140 ev Total Absorber: 1x1020cm-2 Partial(35%) Dense Absorber:2.0x1023cm-2

  17. Hard X-ray IPs: a growing family …& …further complexities at soft energies RXJ1730-0559 a hard IP with a complex Soft spectrum XMM-NEWTON EPIC-pn & MOS INTEGRAL IBIS ISGRI Two temperatures:kT hot = 55keV kT cool=0.17 keV Az=0.4 Black-Body:kTbb=90eV Total Absorber:3.6x1021cm-2 Partial(56%) Dense Absorber:1.4x1023cm-2 OVII Absorption edge@ 0.74keVτ~1.8 Reflection: 6.4keV Fe line:EW=110eV (de Martino et al. 2008,A&A) 3rd IP with absorption edge! (V709 Cas - de Martino et al. 2001; V1223 Sgr – Mukai et al. 2001)  Warm absorber in IPs

  18. Hard IPs……..a growing family …but NOT all of them have a SOFT BB component IGRJ0023+6141 & RXJ2133+5107 Twotemperatures:kT hot >14 keV kT cool=0.17keV EW (6.4keV) = 100 ev Total Absorber: 2x1021cm-2 Partial(36%) Dense Absorber:1x1023cm-2 Three temperatures:kTmax = 40 keV kTmed =5 keV kT low = 1keV EW (6.4keV) = 140 ev Black-Body:kTbb=99eV Partial(45%) Dense Absorber:1x1023cm-2 (Anzolinet al. 2009, sub)

  19. SOFT IPs: An emergingclass QUESTIONS: • Do allIPspossess soft BB component? Geometricfactorsmay play a role(Evans & Hellier 2007) butnotalways(Anzolinet al. 2008) • High kTBB -> LxlocallyexceedingEddington Whathappens at footprints? • IskTBBlinkedtoMagneticFieldStrength? IrradiationbyCyclotron & Bremsstrahlung ? Characteristics: • HeavilyabsorbedNh ~ 1023cm-2BBs • BB temperaturesover a widerrange (30-100eV) • Soft-to-HardLuminosityratiolowerthanPolars • WD spotssmallerforhotterBBs (f ~10-5-10-6) ROSAT: 4 IPs with soft BB similar to Polars (30-60eV) XMM-Newton: Current roster of 13 IPs (42% of class) Absorption dips and BB Polars: Ramsay et al. 04 IPs: Haberl et al. 02, de Martino et al. 06,08 Evans & Hellier 07 Staude et al. 08 Anzolin et al. 08, 09

  20. SOFT IPs: An emerging class Reprocessing at WD poles • Bremsstrahlung irradiates small WD spot areas • Cyclotron radiation beaming on wide areas • BB Temperature is average over spot area (Konig et al. 2006) • Hotter BBs for lowest field IPs • Cooler BBs in higher field IPs (Anzolin et al. 2008) • Polarization searches to confirm the hypothesis A complete censusneededtodrawconclusions!

  21. XMM-NewtonChangingourviewofMCVs • Increasing number of IPs with Soft X-ray BB but with wider Temperature range than Polars • Increasing number (~33%) of Polars with no Soft X-ray BB (Homer et al. 05; Schmidt et al. 05; Ramsay et al.09; Vogel & Schwopeposter yesterday) kTbb Mdot/f1/4 Shifted to the EUV range This is what believed to occur in most IPs • Reprocessing in MCVs occurs over large range of spot areas • Tracing different B,mdot parameter space values?

  22. Conclusions • IdentificationofnewMCVsessentialtounderstand : • EvolutionofMCVs • Potentialrole in GalacticPopulationsofX-raysources • RoleofXMM-Newton in: • Identificationofnewfaintcandidates • Studyoftemporal and spectralproperties • IncreasingsimilaritiesofIPswithPolars: • One or Two-polesactive & secondary pole is soft • IncreasingnumberofIPswith soft BB butwithdifferences • IncreasingPolarswith no soft BB • Westillneed a complete understandingofMCVs • Roleoffundamentalparameters (Bwd,Mwd,Mdot) in emissionproperties

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