Документ взят из кэша поисковой машины. Адрес оригинального документа : http://hea.iki.rssi.ru/conf/hea2008/Presentations/24Dec/Chernyakova_IKI2008.pdf Дата изменения: Fri Jan 16 18:07:16 2009 Дата индексирования: Tue Oct 2 01:18:45 2012 Кодировка: Поисковые слова: воздушные массы

Latest X-ray observations of -ray loud binary systems.
-ray loud binary systems

Maria Chernyakova (DIAS, Ireland/ASC FIAN, Moscow) Andrii Neronov (ISDC, Switzerland) Yasunobu Uchiyama, Tadayuki Takahashi (JAXA, Japan) Felix Aharonian (DIAS, Ireland/MPKP, Germany)

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Known -ray loud binary systems.
-ray loud binary systems

Only 3 binary systems regularly observed in TeV: PSR B1259-63 young pulsar +Be star, P=3.4 y, aper~1013cm L SI + 6 1 3 0 3 comp. source + Be star, P=26.42 d, aper~3x10 cm LS 5039 comp. source + O star, P=3.9 d, aper~1012cm
Radio-to-TeV SED is similar in all systems with maximum shifted to GeV. HESS J0632+057 ­ a new binary system? (J.A.Hinton et al. 2008, astro-ph 0809.0584)
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PSR B1259-63
-ray loud binary systems
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3.4 years orbital period. e~0.87 Stability of the X-ray orbital lightcurve. Correlated variability with a sharp rise ( "two bumps structure" ) is seen in radio, X-ray (and TeV?) bands. Softening (hardening) of the X-ray spectrum on a day scale in the disk.


Spectral evolution
Sz 3

-ray loud binary systems
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Passage through the disk is accompanied by the spectral hardening (up to ~1.2) and softening (~1.6) on a day time scale. During the hardest state (Sz3) the spectral break is observed. Broken power law gives 1~1.3 Ebr~6keV 2~1.8




Short Scale Time Behavior
PN/XMM (1ksec bin)

-ray loud binary systems

tc=8x103[ne/3x109][Ee/10MeV]s ts=103[B/1G]-3/2[s/4keV]
-1/2

s

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Moderate variability is seen on an hour time scale near the disk entrance. Evidence of clumpy structure?



Spectral modeling
Synchrotron
(Tavani&Arons 1997,

-ray loud binary systems

and IC (Neronov&Chernyakova 2006) can be bot h important for X-rays
Khangulyan et al. 2007)

Eic=4[Ee/10MeV]2 keV tic=106[D/1013cm]2[10MeV/Ee] s tKN=103[D/1013cm]2[Ee/1TeV] s ts=103[B/1G]3/2

[s/4keV]

-1/2

s

tc=8x103[ne/3x109][Ee/10MeV]s tesc=106[D/1013cm] [v/107cm/s]-1s

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.... injection of electrons with entrance result in hardening of .... Coulomb losses affect low spectral hardening ....Low energy cut-off (E >10 inj


energies above 10 MeV at the disk the X-ray spectrum on a day scale. energy photons, leading to the MeV) will also lead to deficiency


Spectral modeling (2)
-ray loud binary systems
Synchrotron and IC can be both important for X-rays
Eic=4[Ee/10MeV]2 keV tic=106[D/1013cm]2[10MeV/Ee] s tKN=103[D/1013cm]2[Ee/1TeV] s ts=103[B/1G]-3/2[s/4keV]
-1/2

s

tc=8x103[ne/3x109][Ee/10MeV]s tesc=103[D/1013cm] [v/1010cm/s]-1s

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....KN dominated cooling regime will lead to spectral hardening of the synchrotron component .... injection of electrons at high energies (>1012eV) along with the fast escape (v~c) may lead to the hard X-ray synchrotron spectrum due to the inefficiency of the synchrotron cooling



Comparison of 2 disk passages


-ray loud binary systems

Similar to radio band (Connors 2002) X-ray data are consistent with linear rise followed by power law adiabatic decay. For both synchrotron and IC cooling L~L0(D/D0)n(1-p)/2-2 where p characterize the injection power and n the disk density profile. Assuming p=2, n=3 L~L1,2/(1+t/td)7/2 td=D/V=110±25 d





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Conclusions


-ray loud binary systems
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We present the results of intensive X-ray monitoring campaign of the 2007 PSR B1259-63 periastron passage. System is found to be remarkably stable from one orbit to another. Day time scale spectral evolution with occasional hardening (up to ~1.2) is observed. Break of the spectrum is found during the hardest state of the source. Better TeV data are crucial for the source spectral modeling










LSI +61 303
Chernyakova, Neronov, Walter 2006

-ray loud binary systems
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Compact binary with 26.42 d orbital period. Eccentricity e~0.7 The X-ray emission peaks almost half an orbit before the radio


Longterm evolution
-ray loud binary systems
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The orbital phases of radio flux maximums "drift" with superorbital period P=4.6 year. Evidence for a similar drift in X-rays?


INTEGRAL Observations
-ray loud binary systems
61ks 71ks 30ks 35ks 150ks

7ks 18ks 3ks

107ks

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-ray loud binary systems

Fermi observations


Structure of the Compactified Pulsar Wind Nebula
-ray loud binary systems
t
coulomb

Ee 3x108 cm-3 8x10 [ ][ ]s ne 10 MeV
4
4 38 2

10 erg / s D 10 MeV t IC 5x10 [ ][ cm ] [ ]s 12 Lstar Ee 3x10

1G 1 GHZ t s 4x10 [ ][ ]s B nu
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3/ 2

t

diff

1.5x107 [

R

2 clump 11

10 cm

][

B MeV ] [ 10 ]s 1G Ee

D

w , ff

1 GHZ 2 /3 M 13 5x10 [ ] [ -8 nu 10 M

2 /3

]
sun

[

v
8

- 2/ 3 inf

10 cm / s

]

-1 / 2 T f- [ 5 K] [ ] 0.1 10

1/ 3

cm

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Resulted Spectrum Formation
-ray loud binary systems
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Lightcurves in different energy bands
-ray loud binary systems


Radio:


Comes from the region of the size D

~2-3x1014 cm PWN

The maximum is achieved when 10 MeV electrons efficiently escapes from the region close to the Be star Superorbital modulation is due to the Be disc precession.





X-rays:


The maximum close to the moment of the pulsar passage through the equatorial plane of the inclined disc No second maximum due to the Coulomb losses. Maximum close to periastron





-rays (10 GeV): TeV:

Dip at periastron due to pair-pair production.

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LS 5039
-ray loud binary systems


orbital period is 3.9 d., eccentricity 0.35, at periastron R~2.2R
*

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Aharonian et al. , A&A 2006


INTEGRAL observations
Hoffman, Klochkov, Santangelo et al. 2009 astro-ph 0812.0766

-ray loud binary systems
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Conclusions
-ray loud binary systems
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-ray loud binaries apparently form a separate class of sources powered by interaction of relativistic wind from the compact object with the stellar wind.




The emission from such a system is variable along the orbit, non-thermal X-ray, -ray, and very high-energy -ray emission during the periods of pulsar passing through the dense regions of the companion wind.


Winds collision
-ray loud binary systems
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Due to the intrinsic instabilities in the winds of hot massive stars clumps may form and change the well-ordered structure. Emission is due to the synchrotron, IC, bremsstrahlung, and proton-proton interactions.




TeV emission: IC, bremsstrahlung or proton-proton interactions?
-ray loud binary systems
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The observed TeV lightcurve can be reproduced in the IC model if adiabatic loss dominates or the acceleration efficiency drops at periastron (Khangulyan et al. 06). If the matter density is n~1011cm-3, the bremsstrahlung energy loss is comparable to the IC loss (in KN regime) and proton-proton interaction time. TeV emission can be bremsstrahlung from the compact region of interaction of pulsar and stellar winds.




Short Scale Variability
-ray loud binary systems
The typical variability time due to the Compton cooling is
10 t IC 5 L star

[ ][ ] [ ]
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R 1012

2

1 keV E IC

1/2

ks

The observed short scale variability is an evidence of the clumps in the wind of the Be star. The size of the clump can be estimated as R~vpt~1011cm

Sidoli et. al 2006

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Arguments for pulsar model
Similar to PSR B1259-63 radio and X-ray emission can be explained by the synchrotron and IC emission from the same population of the electrons. Absence of the break in the X-ray spectrum favors the "hidden pulsar" model. Extended radio source has a complicate morphology varying along the orbit (Massi et al. 2004, Dhawan et al. 2006), thus jet emission is unlikely to dominate the spectrum through the whole orbit. The pattern of the source variability in the hardness ratio vs. flux diagram is naturally explained in the compact PWN model and is qualitatively different from the pattern in conventional accreting X-ray binaries

-ray loud binary systems
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