Era the I ntermediate P olars Dde Martino INAFOsservatorio Astronomico di Capodimonte Napoli amp GAnzolin JMBonnetBidaud MFalanga BGaensicke FHaberl ID: 722157
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Slide1
Magnetic CVs in the XMM-Newton Era: the Intermediate Polars D.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.MukaiSlide2
OutlineOpen questions: Evolutionary link between Polars and IPs Role of MCVs in Population of Galactic
X-ray
Sources
Role
of fundamental parameters in accretion and emission properties
Results from XMM-Newton:
Increased IP membership
New X-ray properties: commonalities with Polars
Slide3
Questions on MCV EvolutionMCVs ~20-25% of all CVs vs MWDs~10% of all WDsRK v.7.10 (2008)~40%~50%Slide4
MCV Class Census: Polars IPs Pre-Rosat 18 (60%) 12 (40%) Post-Rosat 55 (70%) 25 (30%) Today 94 (54%) 78 (46%) Candidates increased by 50% in last 4yrs (see Koji Mukai’s IP Web Site)~80%
~70%
QUESTION
Do
IPs evolve towards synchronism?Do IPs harbour lower B field WDs?Slide5
Polars: Beuermann (2000) IPS: Butters et al. 2009 Systematic Survey in Polarized light still missing!Polarimetric UBVRI survey recently started @ NOT (Katajainen et al. 2007; Butters et al. 2009) Spectropolarimetriy @ ESO/VLT attempted but large
oversubscription!
What about B field strengths in IPs?
V405 Aur
BG CMi
V2400 OphPQ Gem
RXJ2133
RXJ1730
WGA1958
V1223 Sgr
ROLE OF SALT TELESCOPE !
Most IPs lie below synchronization line
On average lower B field systems that may evolve towards synchronism
PolarsSlide6
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!Do IPs evolve towards synchronism? ConfirmedO CandidatesX This work XMM-Newton
Norton et al. (2004,2008) propose IPs
at Porb>3hrs with
:
B ≥10 MG
will evolve into PolarsB≤10MG evolve into unobservable low-field Polars or B field re-emerges
when
Mdot
decreases
.
To
keep
spin-equilibrium
Pspin
increases
while
Porb
decreases
->
short
Porb
IPs
should be weakly
desynchronized
X-RAY FOLLOW-UPS ON GOING!Slide7
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)Slide8
Common characteristics 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)
25
INTEGRAL
CVs with
ROSAT
counterpart
INTEGRAL-ROSAT
COLOR DIAGRAM:
Hard spectra with wide range of absorption
Most
RXTE
,
INTEGRAL
&
SWIFT
detected
CVs
are
MCVs
(
Revnistev
et
al. 2004;
Barlow
et
al. 2006;
Bonnet-Bidaud
et
al.2007;
Mukai
et
al.2007;
Bodaghee
et
al. 2007;
Shafter
et
al.
2008,
see also Potter et al. Poster yesterday…….)
MAGNETISM & ASYNCHRONISM
SEEM TO BE
COMMON CHARACTERISTCS
OF HARD X-RAY
CVs
!Slide9
Role of MCVs in Galactic Populations? RXTE & INTEGRAL surveys of Milky Way (Sazonov et al. 2006; Revnivtsev et al. 2006, 2008): XLF [2-10keV] at L<1034erg/s from Coronal
(65%) and CVs (35%)XLF
of CVs [2-12keV]
similar
to XLF[16-60keV] Galactic Ridge emission at E>20keV dominated by MCVs
CHANDRA
Survey
of
Galactic
Center
(
Muno
et
al. 2003;2004;
Ruiter
et
al 2005
):
- 1500
over
2000
Faint
Sources
:
Lx
< 1031 – 1033 erg/s - Hard
spectra: kT > 8keV & Fe H-like and He-like emissions -
Affected by local
absorption
-
Variable
:
Periods
300sec – 4.5hrs
IPs
proposed
to
be
dominant
population
See
also
poster on
Chandra
Survey
of
Galactic Bulge
by Torres et al. (
Tuesday
)
IPs
a
still
hidden
population
of
XRBs
?Slide10
QUESTIONSIPs a still hidden population of Galactic X-ray sources?Confirm IP Membership of CandidatesWhat are the true Polar progenitors? Why most Hard X-ray CVs are asynchronous?Emission properties & fundamental parameters Do all IPs possess a SOFT X-ray component?Hunting for Soft X-ray & Polarized IPs
Characterize spectral components
Sensitive Broad-Band
X-ray
observations are essential! Slide11
Role of XMM-Newton Uninterrupted observations of faint sources :- Secure membership identification- Accretion mode diagnostic
: Disc -
Direct (no disc)
accretion
,-, Disc
overflow (Hybrid)Energy dependent X-Ray/UV/Optical pulses:
-
Geometry
and
magnetic
field
complexity
-
Sites
of
Primary
&
Reprocessed
radiation
-
Absorption
effects
X-Ray spectra:
- Accretion region diagnostic: Pre-Shock, Post-Shock, WD irradiation
XMM-Newton
observed
20
IPs
:
Confirmed
IP status
for
11
candidates
!
Provided
new
hints
in
emission
propertiesSlide12
X-ray Periodicities Complexities in Energy dependent X-Ray Power SpectraOne Pole disc-fed (de Martino et al. 2005)One Pole Hybrid(Anzolin et al. 2008)
ω
ω
ω
-
ΩSlide13
X-ray Periodicities Complexities in Energy dependent X-Ray Power SpectraTwo Poles disc-fed(de Martino et al. 2008)Two Pole Hybrid(de Martino et al. 2006)ω
ω
-Ω
2
ω
ω
3
ωSlide14
X-ray Pulses Energy dependent structured pulsationsOne hard PoleTwo hard & Soft PolesStronger Soft PolePrimary hard & soft Pole + Secondary soft Pole
See
also
Koji Mukai’s Poster #87 Slide15
X-ray Spectral PropertiesStarting from the simplest case of HT Cam(de Martino et al. 2005)Multi-temperature post-shock flow :EM(T) ≈(T/Tmax)α - kTmax=20keV; α=0.7 Az=0.6- Absorption negligible(de Martino et al. 2005,A&A)
-He-like OVII triplet: no forbidden line -> high density limit ne> 5
x1012cm-3
- OVII/OVIII ratio -> kTmin=
0.3keV- V(OVIII)1000km/s-> Vshock≈Vff/4 Slide16
X-ray Spectral PropertiesComplexities at soft energiesUU Col a Soft ROSAT IPTwo temperatures: kT hot=11 keV kT cool=0.18 keV Az=0.4Black-Body: kTbb=50eVPartial(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 spectraSlide17
X-ray Spectral PropertiesRXJ0704+2625 & RXJ1803+4012One temperature: kT hot > 40 keV Black-Body: kTbb=84eVEW (6.4keV) = 140 evTotal Absorber: 1x1020cm-2Partial(35%) Dense Absorber: 2.0x1023cm-2
XMM-Newton
finds new
SOFT X-RAY
IPs
Multi-temperatures: kT max
~30
keV
Black-Body
:
kTbb=95eV
Partial
(
40%
) Dense
Absorber
:
3x10
23
cm
-2
(
Anzolin
et
al. 2008)Slide18
Hard X-ray IPs: a growing family…& …further complexities at soft energiesRXJ1730-0559 a hard IP with a complex Soft spectrumTwo temperatures: kT hot = 55keV kT cool=0.17 keV Az=0.4Black-Body: kTbb=90eVTotal Absorber: 3.6x1021cm-2Partial(56%)
Dense Absorber: 1.4x1023
cm-2
OVII
Absorption edge
@ 0.74keV τ~1.8Reflection: 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
XMM-NEWTON EPIC-pn & MOS
INTEGRAL
IBIS ISGRISlide19
Hard IPs……..a growing familyIGRJ0023+6141 & RXJ2133+5107Two temperatures: kT hot >14 keV kT cool=0.17keV EW (6.4keV) = 100 evTotal Absorber: 2x1021cm-2Partial(36%
) Dense Absorber:
1x1023cm-2
…but NOT all of them have a SOFT BB component
Three
temperatures: kT max = 40 keV kTmed =5
keV
kT
low = 1keV
EW (6.4keV)
= 140
ev
Black-Body
:
kTbb=99eV
Partial
(
45%
) Dense
Absorber
:
1x10
23
cm
-2
(
Anzolin
et
al. 2009, sub)Slide20
SOFT IPs: An emerging class ROSAT: 4 IPs with soft BB similar to Polars (30-60eV)XMM-Newton: Current roster of 13 IPs (42% of class)Characteristics: Heavily absorbed Nh ~ 1023cm-2 BBsBB temperatures over a wider range (30-100eV)Soft-to-Hard
Luminosity ratio lower than
Polars WD spots smaller
for
hotter BBs (f ~10-5-10-6)Polars: Ramsay et al. 04IPs: Haberl et al. 02, de Martino et al. 06,08Evans & Hellier 07Staude et al. 08Anzolin et al. 08, 09
QUESTIONS:
Do
all
IPs
possess
soft BB
component
?
Geometric
factors
may
play a
role
(Evans &
Hellier
2007)
but
not
always
(
Anzolin
et
al. 2008)
High
kT
BB
->
Lx
locally
exceeding
Eddington
What
happens
at
footprints
?
Is
kT
BB
linked
to
Magnetic
Field
Strength
?
Irradiation
by
Cyclotron
&
Bremsstrahlung
?
Absorption dips and BB Slide21
Reprocessing at WD polesBremsstrahlung irradiates small WD spot areas Cyclotron radiation beaming on wide areasBB Temperature is average over spot area(Konig et al. 2006)Hotter BBs for lowest field IPsCooler BBs in higher field IPs (Anzolin et al. 2008)Polarization searches to confirm the hypothesis SOFT IPs: An emerging class
Name
kT
BB (eV)Anzolin et al. 2008,09Mag.Field
(MG)
Butters et al.2009
PQ Gem
48-66
8-21
V405
Aur
65-73
~30
RXJ1730-0559
90-93
>5MG
RXJ2133+51
94-102
>5MG
V2400
Oph
103-107
8-27
A complete
census
needed
to
draw
conclusions
! Slide22
XMM-Newton Changing our view of MCVsIncreasing number of IPs with Soft X-ray BB but with wider Temperature range than PolarsIncreasing number (~33%) of Polars with no Soft X-ray BB (Homer et al. 05; Schmidt et al. 05; Ramsay et al.09; Vogel & Schwope poster 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 areasTracing different B,mdot parameter space values? Slide23
Why Hard X-ray CVs? Shock temperature related to WD Mass:Mwd ≈ 0.45 (kTshock /20keV) 0.75 Post Shock Region mainly cools via Bremsstrahlung Temperature and Emissivity distrubution in PSR (Suleimanov et al. 2005; 2008)Masses are over-estimated using 1T flow (Saxton et al. 2007)Masses of MCVs not different from non-MCVs Slide24
For B≤ 5-10MG Bremsstrahlung is main cooling 1T and 2T flows predict similar X-ray continua up to 5keV 1T flow is harder above 5keV (Saxton et al. 2007) For B>30MG and low dm/dt Cyclotron is important lowers Shock height and decreases Te Bremsstrahlung flux can be drastically reduced (Fischer & Beuermann 2001) Is asynchronism is a signature of low B systems ? Probably yes for IPs
Why most hard X-ray CVs are asynchronous?
Radiative losses by cyclotron & bremsstrahlung forB>1MG
Frad ≈
ρ
a Te b One-fluid plasma in low B and high flow rates(Wu et al. 1994; Fisher & Beuermann 2001; Beuermann 2003; Saxton et al. 2005; 2007)
10keV
40keV
B=30 MG dm/dt=100,10,1,0.1 g/cm2/s (Fischer & Beuermann 2001)
100
10
1
0.1
IPs and moderately low field Polars with high dm/dt may be hard X-ray sourcesSlide25
What about Hard X-ray Polars?NAMEB (MG)SYNCHROP_orb (hr)V834 Cen23YES
1.7
SwiftJ2319+26?
NO:
3.0
BY Cam 41NO
3.4
V1432
Aql
28-35
NO
3.4
IGR/Swift
J
1453-55
(Potter
et al Poster
on Monday)
INTEGRAL/SWIFT detected POLARS
Could they be high rate accretors?Slide26
Another hard X-ray view of Polars? NAMEB (MG)SYNCHROP_orb (hr)SDSS0155+0029YES
1.45
CE
Gru
32:
YES1.8CD Ind
15
NO
1.8
WW
Hor
15
YES
1.9
V2301
Oph
7
YES
1.9
SDSS1700+36
?
YES
1.9
SDSS0729+36
?
YES
2.5
V349
Pav
?
YES
2.7
XMMJ2250+57
?
YES
2.9
V1500
Cyg
25-50:
NO
3.4
POLARS with Hard X-ray spectra from XMM-Newton
(Ramsay et al. 2004;2009; Homer et al. 2005; Schmidt et al.2005)
Changing our view of MCVs:
Increasing number of
Polars
with no Soft X-ray BB
(see Ramsay et al.
2009; Vogel &
Schwope
poster yesterday)
kTbb
Mdot
/f
1/4
Shifted to the EUV range?
This is what believed to occur in IPs
Increasing number of IPs with Soft X-ray BB but with wider Temperature range
Reprocessing over wide range of spot areas
Hard & Soft MCVs may trace different
B,mdot
parameter space Slide27
ConclusionsIdentification of new MCVs essential to understand :Evolution of MCVsPotential role in Galactic Populations of X-ray sources Role of XMM-Newton
in: Identification of new
faint candidates Study
of
temporal and spectral properties Increasing similarities of IPs with Polars:One or Two-poles active & secondary pole
is
soft
Increasing
number
of
IPs
with
soft BB
but
with
differences
Increasing
Polars
with
no soft BB
We
still need a complete
understanding of MCVs
Role of fundamental parameters (Bwd,Mwd,
Mdot) in emission properties