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

Close-by young isolated NSs:
A new test for cooling curves
Sergei Popov
(Sternberg Astronomical Institute)
Co-authors: H.Grigorian, R. Turolla, D. Blaschke
(astro-ph/0411618)
Plan of the talk
 Abstract
 Close-by NSs
 Population synthesis
 Log N – Log S
 Test of cooling curves
 Final conclusions
2
Abstract of the talk
We propose
a new test of
cooling curves.
It is based on
the Log N – Log S
distribution.
It should be used
together with the
standard test
temperature vs. age
3
Isolated neutron stars population:
in the Galaxy and at the backyard
 INSs appear in many flavours
 Radio pulsars
 AXPs
 SGRs
 CCOs
 RINSs
 Local population of young NSs
is different (selection)
Radio pulsars
Geminga+
RINSs
4
Close-by radioquiet NSs
 Discovery:




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
 Emission properties
 Interstellar absorption
A brief review on population
synthesis in astrophysics can
be found in astro-ph/0411792
 Detector properties
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Solar vicinity
 Solar neighborhood is not a






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
10
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)
astro-ph/0305599
11
Cooling of NSs
 Direct URCA
 Modified URCA
 Neutrino bremstrahlung
 Superfluidity
 Exotic matter (pions,
quarks, hyperons, etc.)
In our study for illustrative purposes
we use a set of cooling curves calculated by
Blaschke, Grigorian and Voskresenski (2004)
in the frame of the Nuclear medium cooling model
12
Standard test: temperature vs. age
Kaminker et al. (2001)
13
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)
14
Log N – Log S: early results
 Task: to understand the





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
15
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.








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
18
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
19
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
20
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
21
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
22
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
23
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
24
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
25
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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Resume
 Log N – Log S for close-by NSs can serve as a
test for cooling curves
 Log N – Log S test can include NSs with
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.
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THAT’S ALL. THANK YOU!
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Radio detection
Malofeev et al. (2005) reported detection of
1RXS J1308.6+212708 (RBS 1223)
in the low-frequency band (60-110 MHz)
with the radio telescope in Pushchino.
(back)
32
Evolution of NS:
spin + magnetic field
Ejector → Propeller → Accretor → Georotator
1 – spin-down
2 – passage through a molecular cloud
3 – magnetic field decay
Lipunov (1992)
astro-ph/0101031
33
Model I
 Pions.
 Gaps from Takatsuka & Tamagaki
(2004)
 Ts-Tin from Blaschke, Grigorian,
Voskresenky (2004)
Can reproduce observed Log N – Log S
(back)
34
Model IX
 No Pions
 Gaps from Takatsuka &
Tamagaki (2004)
 Ts-Tin from Blaschke,
Grigorian, Voskresenky
(2004)
Can reproduce observed Log N – Log S
(back)
35
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)
36
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)
37
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)
38
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)
39
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)
40
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)
41
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)
42