Transcript Document

Isolated Neutron Stars
for
ART, eROSITA and LOBSTER
Sergei Popov
(SAI MSU)
Good old classics
The pulsar in the Crab nebula
A binary system
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The new zoo of neutron stars
During last 10 years
it became clear that neutron stars
can be born very different.
In particular, absolutely
non-similar to the Crab pulsar.
o Compact central X-ray sources
in supernova remnants.
o Anomalous X-ray pulsars
o Soft gamma repeaters
o The Magnificent Seven
o Unidentified EGRET sources
o Transient radio sources (RRATs) ….
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Main reviews
•NS basics:
physics/0503245
•SGRs & AXPs:
-Recent observations
AXPs
SGRs
astro-ph/0406133 !!!!
astro-ph/0610304
astro-ph/0608364
•Theory of magnetars:
astro-ph/0504077
•Central compact X-ray
sources in supernova
remnants:
astro-ph/0311526
•The Magnificent Seven:
astro-ph/0609066 !!!!
•RRATs:
astro-ph/0608311
•Cooling of NSs:
astro-ph/0508056 !!!!
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Wanted!
There are several types of uncatchable
compact objects which still are not detected:
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Isolated accreting NSs
Isolated BHs
Isolated NSs on the Propeller stage
NSs in the galactic halo
Extragalactic magnetars
Also we want to detect more cooling INSs.
Finally, there are several interesting types
of accreting binaries, which can be detected:
• Massive NS accreting from WDs
• Accreting magnetars (including magnetors)
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Evolution of NSs. I.:
temperature
[Yakovlev et al. (1999) Physics Uspekhi]
First papers on the thermal
evolution appeared already
in early 60s, i.e. before
the discovery of radio pulsars.
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Evolution of neutron stars. II.:
rotation + magnetic field
Ejector → Propeller → Accretor → Georotator
1 – spin down
2 – passage through a molecular cloud
3 – magnetic field decay
astro-ph/0101031
See the book by Lipunov (1987, 1992)
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Isolated NS Census
Rather conservative
evolutionary scheme
was used.
For example,
supersonic propellers
have not been considered
(Ikhsanov 2006).
astro-ph/9910114
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Accreting isolated NSs
At small fluxes <10-13 erg/s/cm2 accretors can become more abundant
than coolers. Accretors are expected to be slightly harder:
300-500 eV vs. 50-100 eV. Good targets for eROSITA!
From several hundreds up to
several thousands objects
at fluxes about few X 10-14,
but difficult to identify.
Monitoring is important.
Also isolated accretors can
be found in the Galactic center
(Zane et al. 1996,
Deegan, Nayakshin 2006).
astro-ph/0009225
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Young cooling radio dim NSs
Source
Period, s
RX 1856
7.05
RX 0720
8.39
RBS 1223
10.31
RBS 1556
RX 0806
The Magnificent seven
6.88?
11.37
RX 0420
3.45
RBS 1774
9.44
Poster by Malofeev
Radio quiet (?)
Close
Young
Thermal emission
Spectral features
Long periods
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More cooling NSs
eROSITA has better sensitivity
for sources with T>200 eV.
We expect that there are more
INS in the directions towards
OB associations.
These INS are younger and hotter
than the Magnificent Seven.
eROSITA can find few dozens.
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Known magnetar candidates
SGRs
 0526-66
 1627-41
 1806-20
 1900+14
 +candidates
AXPs
 CXO 010043.1-72
 4U 0142+61
 1E 1048.1-5937
 CXOU J164710.3 1 RXS J170849-40
 XTE J1810-197
 1E 1841-045
 AX J1844-0258
 1E 2259+586
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SGRs and AXPs
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Are SGRs and AXPs brothers?
Bursts of AXPs
 Spectral properties
 Quiescent periods
of SGRs (0525-66
since 1983)
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Gavriil et al. 2002
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AXPs: bursts and transients
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Typical bursts of
SGR 1806-29,
SGR 1900+14
And of AXP 1E
2259+586
detected by RXTE
(from Woods, Thompson astro-ph/0406133)
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SGRs: monitoring and extraG
SRG detectors can contribute to
observations of SGRs.
[D. Frederiks et al. astro-ph/0609544]
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Compact central X-ray sources
in supernova remnants
Cas A
Puppis A
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RRATs: also young coolers?
Rotating Radio Transients
have been discovered recently
(McLaughlin et al. 2005).
They can represent a very
numerous population of NSs.
One of RRATs is identified in
Chandra data as a young
cooling NS. Slightly hotter
than the Magnificent seven
(Reynolds et al. 2006).
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Unidentified EGRET sources
Grenier (2000), Gehrels et al. (2000)
Unidentified sources are divided into several groups.
One of them has sky distribution similar to the Gould Belt objects.
Search in 56 EGRET error-boxes resulted in no PSR detections
(Crawford et al. 2006).
GLAST (and, probably, AGILE) can help to solve this problem.
eROSITA and LOBSTER also can contribute.
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Проект Джильда-Гала
Проект в основном создается
учеными МИФИ
(Институт Космофизики)
Солнечно-синхронная
круговая орбита
Высота орбиты 835 км
Наклонение 98.68 градуса
 Чувствительность от 10 МэВ
 Большое поле зрения
 Хороший тайминг
Запуск 2010 год
Срок работы 5-7 лет
Мониторинг неба в гамма-лучах
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Isolated BHs
Isolated BHs can be detected due to accretion
or due to some exotic emission.
Punsly et al. (astro-ph/0007465) predict that
some of EGRET unidentified sources can be
isolated BHs. Corresponding X-ray luminosity
is about 1033-1034 erg/s.
astro-ph/0511224
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Massive NS accreting from WDs
Observations of very massive NSs are important
for EOS studies.
Probably, most massive NSs cannot be observed
as radio pulsars.
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Binaries with magnetars magnetors
Can RCW 103 be a prototype?
6.7 hour period (de Luca et al. 2006)
Possible explanations:
1. Magnetar, spun-down by disc
2. Double NS system
3. Low-mass companion + magnetar=
magnetor
RCW 103
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Conclusion
There are several types
of sources: CCOs, M7,
SGRs, AXPs, RRATs ...
 Unsolved problems:
1. Are there links?
2. Reasons for diversity
 Detectors on-board SRG
can contribute in
discovery of new INS and
other interesting objects
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Main reviews
Труды ГАИШ том 72 (2003)
•NS basics:
physics/0503245
•SGRs & AXPs:
astro-ph/0406133
•Magnetars:
-Observations
AXPs
SGR
- Theory
astro-ph/0610304
astro-ph/0608364
astro-ph/0504077
•Central compact X-ray
sources in supernova
remnants:
astro-ph/0311526
•The Magnificent Seven:
astro-ph/0609066
•RRATs:
astro-ph/0608311
•Cooling of NSs:
astro-ph/0508056
http://xray.sai.msu.ru/~polar/sci_rev/ns.html
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(www.bradcovington.com)
Dorothea Rockburne
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Magnetorotational evolution of
radio pulsars
Spin-down.
Rotational energy is released.
The exact mechanism is
still unknown.
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Known AXPs
Sources
Periods, s
CXO 010043.1-72 8.0
4U 0142+61
8.7
1E 1048.1-5937
6.4
CXOU J164710.2-
10.6
1RXS J170849-40 11.0
XTE J1810-197
5.5
1E 1841-045
11.8
AX J1845-0258
7.0
1E 2259+586
7.0
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What is special about
magnetars?
Link with massive stars
There are reasons to suspect
that magnetars are connected
to massive stars.
Link to binary stars
There is a hypothesis that
magnetars are formed in close
binary systems
(astro-ph/0505406).
Westerlund 1
The question is still on the list.
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Close-by radio quiet NSs
Discovery:
Walter et al.
(1996)
 Proper motion and
parallax:
RX J1856.5-3754
Kaplan et al.
 No pulsations
 Thermal spectrum
 Later on:
six brothers
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27 Dec 2004
Giant flare
SGR 1806-20
Spike 0.2 s
 Fluence 1 erg/cm2
 E(spike)=3.5 1046 erg
 L(spike)=1.8 1047 erg/s
 Long «tail» (400 s)
 P=7.65 s
 E(tail) 1.6 1044 erg
 Distance 15 kpc

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SGRs: periods and giant flares
P, s
Giant flares
 0526-66
8.0
5 March 1979
 1627-41
6.4
 1806-20
7.5
27 Dec 2004
 1900+14
5.2
27 Aug 1998
New result:
oscillations
in the “tail”.
“Trembling”
of the crust
(Israel et al. 2005,
Watts and Strohmayer 2005).
18 June 1998 (?)
See the review in
Woods, Thompson
astro-ph/0406133
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Anomalous X-ray pulsars
Identified as a separate group in 1995.
(Mereghetti, Stella 1995 Van Paradijs et al.1995)
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Similar periods (5-10 sec)
Constant spin down
Absence of optical companions
Relatively weak luminosity
Constant luminosity
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