Transcript Close-by young isolated neutron stars (and black holes)

Cooling constraints for color
superconductivity in hybrid stars
Sergei Popov
(Sternberg Astronomical Institute)
Co-authors: D. Blaschke, H.Grigorian
Plan of the talk
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Intro. Close-by NSs
Cooling of compact stars
Population synthesis of NSs
Solar vicinity
Some (old) results
Two tests of cooling
Brightness constraint
Sensitivity of two tests
Mass constraint
Hybrid stars
New prospects and results
Final conclusions
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Isolated neutron stars population:
in the Galaxy and at the backyard
 INSs appear in many flavours
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Radio pulsars
AXPs
SGRs
CCOs
RINSs (ICoNS)
RRATs
 Local population of known
young NSs is different (selection)
Radio pulsars
Geminga+
EGRET unidentified sources
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RINSs (ICoNS)
Isolated neutron stars population:
in the Galaxy and at the backyard
 INSs appear in many flavours
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Radio pulsars
AXPs
SGRs
CCOs
RINSs
RRATs
 Local population of known
young NSs is different (selection)
Radio pulsars
Geminga+
EGRET unidentified sources
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RINSs (ICoNS)
Compact central objects in SNRs
Cas A
RCW 103
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Known magnetars
 SGRs
 AXPs
 0526-66
 CXO 010043.1-72
 1627-41
 4U 0142+61
 1806-20
 1E 1048.1=5937
 1900+14
 1 RXS J170849-40
 +candidates
 XTE J1810-197
 1E 1841-045
 AX J1844-0258
 1E 2259+586
(СТВ 109)
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SGRs: periods and bursts
 0526-66
 1627-41
 1806-20
 1900+14
+candidates
P, sec
Giant bursts
8.0
5 March 1979
6.4
18 June 1998 (?)
7.5
24 Dec 2004
5.2
27 Aug 1998
See a review in
Woods, Thompson
astro-ph/0406133
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Known AXPs
Source
Period, sec
CXO 010043.1-72
8.0
4U 0142+61
8.7
1E 1048.1-5937
6.4
1RXS J170749-40
11.0
XTE J1841-197
5.5
1E 1841-045
11.8
AX J1844-0258
7.0
1E 2259+586
7.0
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P-Pdot for new transient sources:
RRATs – Rapid RAdio Transients
McLaughlin et al. 2006
Nature
Estimates show that
there should be about
400 000
sources of this type
in the Galaxy
High formation rate
makes RRATs probable
relatives of ICoNS,
not of magnetars.
(astro-ph/0603258)
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Close-by radioquiet NSs or ICoNS
 Discovery:
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Walter et al. (1996)
Proper motion and
distance: Kaplan et al.
No pulsations
Thermal spectrum
Later on: six brothers
RX J1856.5-3754
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Magnificent Seven
Name
Period, s
RX 1856
-
RX 0720
8.39
RBS 1223
10.31
RBS 1556
-
RX 0806
11.37
RX 0420
3.45
RBS 1774
9.44
Radioquiet (?)
Close-by
Thermal emission
Long periods
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Population of close-by young NSs
 Magnificent seven
 Geminga and 3EG J1853+5918
 Four radio pulsars with thermal emission
(B0833-45; B0656+14; B1055-52; B1929+10)
 Seven older radio pulsars, without detected
thermal emission.
We need
population synthesis studies
of this population
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Population synthesis: ingredients
 Birth rate
 Initial spatial distribution
 Spatial velocity (kick)
 Mass spectrum
 Thermal evolution
 Interstellar absorption
 Detector properties
A brief review on population
synthesis in astrophysics can
be found in astro-ph/0411792
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Cooling of NSs
 Direct URCA
 Modified URCA
 Neutrino bremstrahlung
 Superfluidity
 Exotic matter (pions,
quarks, hyperons, etc.)
Studies of cooling of NSs is one of few ways to obtain
information about interiors of compact objects, and
about physical processes under extreme conditions.
(see a recent review in astro-ph/0508056)
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Population synthesis
Gould Belt : 20 NS Myr-1
Gal. Disk (3kpc) : 250 NS Myr-1
• Cooling curves by
• Blaschke et al.
• Mass spectrum
ROSAT
18°
Arzoumanian et al. 2002
Gould Belt
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Solar vicinity
 Solar neighborhood is not a
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typical region of our Galaxy
Gould Belt
R=300-500 pc
Age: 30-50 Myrs
20-30 SN per Myr (Grenier 2000)
The Local Bubble
Up to six SN in a few Myrs
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The Gould Belt
 Poppel (1997)
 R=300 – 500 pc
 Age 30-50 Myrs
 Center at 150 pc from
the Sun
 Inclined respect to the
galactic plane at 20
degrees
 2/3 massive stars in
600 pc belong to the
Belt
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Log of the number of sources
brighter than the given flux
Log N – Log S
calculations
-3/2 sphere:
number ~ r3
flux
~ r-2
-1 disc:
number ~ r2
flux
~ r-2
Log of flux (or number counts)
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Results – 2003: Log N – Log S
 Task: to understand the
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Gould Belt contribution
Calculate separately
disc (without the belt)
and both together
Cooling curves from
Kaminker et al. (2001)
Flat mass spectrum
Single maxwellian kick
Rbelt=500 pc
astro-ph/0304141
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Two tests
Age – Temperature
&
Log N – Log S
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Standard test: temperature vs. age
Kaminker et al. (2001)
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Log of the number of sources
brighter than the given flux
Log N – Log S
calculations
-3/2 sphere:
number ~ r3
flux
~ r-2
-1 disc:
number ~ r2
flux
~ r-2
Log of flux (or number counts)
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Log N – Log S as an additional test
 Standard test: Age – Temperature
 Sensitive to ages <105 years
 Uncertain age and temperature
 Non-uniform sample
 Log N – Log S
 Sensitive to ages >105 years
(when applied to close-by NSs)
 Definite N (number) and S (flux)
 Uniform sample
 Two test are perfect together!!!
astro-ph/0411618
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List of models (Blaschke et al. 2004)
Blaschke et al. used 16
sets of cooling curves.
They were different in
three main respects:
1. Absence or presence
of pion condensate
2. Different gaps for
superfluid protons and
neutrons
3. Different Ts-Tin
Pions Crust
 Model I.
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Yes
Model II. No
Model III. Yes
Model IV. No
Model V. Yes
Model VI. No
Model VII. Yes
Model VIII.Yes
Model IX. No
C
D
C
C
D
E
C
C
C
Gaps
A
B
B
B
B
B
B’
B’’
A
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Model I
 Pions.
 Gaps from Takatsuka & Tamagaki
(2004)
 Ts-Tin from Blaschke, Grigorian,
Voskresenky (2004)
Can reproduce observed Log N – Log S
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Model II
 No Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1
 Ts-Tin from Tsuruta (1979)
Cannot reproduce observed Log N – Log S
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Model III
 Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1
 Ts-Tin from Blaschke,
Grigorian, Voskresenky (2004)
Cannot reproduce observed Log N – Log S
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Model IV
 No Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1
 Ts-Tin from Blaschke, Grigorian,
Voskresenky (2004)
Cannot reproduce observed Log N – Log S
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Model V
 Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1
 Ts-Tin from Tsuruta (1979)
Cannot reproduce observed Log N – Log S
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Model VI
 No Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1
 Ts-Tin from Yakovlev et al.
(2004)
Cannot reproduce observed Log N – Log S
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Model VII
 Pions
 Gaps from Yakovlev et
al. (2004), 3P2 neutron
gap suppressed by 0.1.
1P proton gap
0
suppressed by 0.5
 Ts-Tin from Blaschke,
Grigorian, Voskresenky
(2004)
Cannot reproduce observed Log N – Log S
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Model VIII
 Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1. 1P0
proton gap suppressed by
0.2 and 1P0 neutron gap
suppressed by 0.5.
 Ts-Tin from Blaschke,
Grigorian, Voskresenky
(2004)
Can reproduce observed Log N – Log S
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Model IX
 No Pions
 Gaps from Takatsuka &
Tamagaki (2004)
 Ts-Tin from Blaschke,
Grigorian, Voskresenky
(2004)
Can reproduce observed Log N – Log S
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HOORAY!!!!
Log N – Log S can select models!!!!!
Only three (or even one!) passed the second test!
…….still………… is it possible just to update
the temperature-age test???
May be Log N – Log S is not necessary?
Let’s try!!!!
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Brightness constraint
 Effects of the crust
(envelope)
 Fitting the crust it is
possible to fulfill the
T-t test …
 …but not the
second test:
Log N – Log S !!!
(H. Grigorian astro-ph/0507052)
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Sensitivity of Log N – Log S
 Log N – Log S is very sensitive to gaps
 Log N – Log S is not sensitive to the crust if it is
applied to relatively old objects (>104-5 yrs)
 Log N – Log S is not very sensitive to presence or
absence of pions
Model I (YCA) Model II (NDB) Model III (YCB)
Model IV (NCB) Model V (YDB) Model VI (NEB)
Model VII(YCB’) Model VIII (YCB’’) Model IX (NCA)
We conclude that the two test complement each other
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Mass constraint
• Mass spectrum has to be taken
into account when discussing
data on cooling
• Rare masses should not be used
to explain the cooling data
• Most of data points on T-t plot
should be explained by masses
<1.4 Msun
In particular:
• Vela and Geminga should not be
very massive
Subm. to Phys. Rev .C
nucl-th/0512098
(published as a JINR [Dubna]
preprint)
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Hybrid stars
We use models of HySs
introduced by Grigorian et al. (2005)
Phys. Rev. C 71, 045801
astro-ph/0511619
2SC phase
μc = 330 MeV
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Mass spectrum
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List of models
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Model I
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Model II
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Model III
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Model IV
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Resume for HySs
One model among four was able to pass all tests.
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Population synthesis –
recent improvements
1. Spatial distribution of progenitor stars
a) Hipparcos stars up to 400 pc
[Age: spectral type & cluster age (OB ass)]
b) Star associations: birth rate ~ Nstar
c) Field stars in the disc up to 3 kpc
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Population synthesis –
recent improvements
2. Spatial distribution of ISM (NH)
+ new cross sections & abundances
1kpc
1kpc
instead of :
now :
(by Bettina Posselt)
Further improvements:
• Mass spectrum
• fainter XMM EPIC PN count rates
• cooling curves (Grigorian et al. 2000,
Popov et al . 2006)
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First results
The new initial distribution of progenitor stars:
Popov et al. 2005
For comparison: ROSAT, old ISM distribution, masses etc. as before
Count rate > 0.05 cts/s
New
b= +90°
Col 121 +Ori OB ?
l=90°
l=180°
l=270°
Sco OB2 ?
Cep + Cyg Ass
?
GB 500 pc
GB 300 pc
b= -90°
Outlook
Different log N - log S curve for distinct sky regions
Population synthesis for fainter (XMM) sources
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Resume
 We live in a very interesting region of the Milky Way!
 Log N – Log S test can include NSs with
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unknown ages, so additional sources
(like the Magnificent Seven) can be used
to test cooling curves
Two tests (LogN–LogS and Age-Temperature) are
perfect together.
Mass constraint can be an important limitation.
Some models for HySs successfully passed all test.
We are looking forward to have a more detailed model.
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THAT’S ALL. THANK YOU!
Collaborators
on pop. synthesis
of isolated NSs:
D. Blaschke,
M. Colpi,
H. Grigorian,
V. Lipunov,
B. Posselt,
M. Prokhorov,
A. Treves,
R. Turolla
Also thanks to:
F. Haberl,
J. Trumper,
D. Voskresenski
50
Radio detection
Malofeev et al. (2005) reported
detection of
1RXS J1308.6+212708
(RBS 1223)
in the low-frequency band (60110 MHz)
with the radio telescope in
Pushchino.
Malofeev et al, Atel #798, 2006
1RXS J2143.7+065419 (RBS 1774)
51
(back)
Model I
 Pions.
 Gaps from Takatsuka & Tamagaki
(2004)
 Ts-Tin from Blaschke, Grigorian,
Voskresenky (2004)
Can reproduce observed Log N – Log S
(back)
52
Model IX
 No Pions
 Gaps from Takatsuka &
Tamagaki (2004)
 Ts-Tin from Blaschke,
Grigorian, Voskresenky
(2004)
Can reproduce observed Log N – Log S
(back)
53
Model III
 Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1
 Ts-Tin from Blaschke,
Grigorian, Voskresenky (2004)
Cannot reproduce observed Log N – Log S
(back)
54
Model II
 No Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1
 Ts-Tin from Tsuruta (1979)
Cannot reproduce observed Log N – Log S
(back)
55
Model IV
 No Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1
 Ts-Tin from Blaschke, Grigorian,
Voskresenky (2004)
Cannot reproduce observed Log N – Log S
(back)
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Model V
 Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1
 Ts-Tin from Tsuruta (1979)
Cannot reproduce observed Log N – Log S
(back)
57
Model VI
 No Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1
 Ts-Tin from Yakovlev et al.
(2004)
Cannot reproduce observed Log N – Log S
(back)
58
Model VII
 Pions
 Gaps from Yakovlev et
al. (2004), 3P2 neutron
gap suppressed by 0.1.
1P proton gap
0
suppressed by 0.5
 Ts-Tin from Blaschke,
Grigorian, Voskresenky
(2004)
Cannot reproduce observed Log N – Log S
(back)
59
Model VIII
 Pions
 Gaps from Yakovlev et al.
(2004), 3P2 neutron gap
suppressed by 0.1. 1P0
proton gap suppressed by
0.2 and 1P0 neutron gap
suppressed by 0.5.
 Ts-Tin from Blaschke,
Grigorian, Voskresenky
(2004)
Can reproduce observed Log N – Log S
(back)
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NS+NS binaries
Pulsar
B1913+16
B2127+11C
B1534+12
J0737-3039
J1756-2251
Pulsar mass
Companion mass
1.44
1.35
1.33
1.34
1.40
1.39
1.36
1.35
1.25
1.18
(PSR+companion)/2
J1518+4904
J1811-1736
J1829+2456
1.35
1.30
1.25
(David Nice, talk at Vancouver)
(Back)
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P-Pdot for new transient sources:
RRATs
McLaughlin et al. 2006
Nature
Estimates show that
there should be about
400 000
sources of this type
in the Galaxy
High formation rate
makes RRATs probable
relatives of Mag.7,
not of magnetars.
(astro-ph/060; MNRAS)
(back)
62
Mass spectrum of NSs
 Mass spectrum of local
young NSs can be
different from the
general one (in the
Galaxy)
 Hipparcos data on
near-by massive stars
 Progenitor vs NS mass:
Timmes et al. (1996);
Woosley et al. (2002)
(masses of secondary objects in NS+NS)
astro-ph/0305599
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Progenitor mass vs. NS mass
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Woosley et al. 2002