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)
Dec 20, 2015
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)
2
Plan of the talk
Abstract Close-by NSs Population synthesis Log N – Log S Test of cooling curves Final conclusions
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Abstract of the talk
We propose a new test ofcooling curves.
It is based onthe Log N – Log Sdistribution.
It should be usedtogether with thestandard testtemperature vs. age
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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 pulsarsGeminga+RINSs
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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-byThermal emissionLong 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 Detector properties
A brief review on populationsynthesis in astrophysics canbe found in astro-ph/0411792
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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
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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
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Cooling of NSs
Direct URCA Modified URCA Neutrino bremstrahlung Superfluidity Exotic matter (pions,
quarks, hyperons, etc.)
In our study for illustrative purposeswe use a set of cooling curves calculated by Blaschke, Grigorian and Voskresenski (2004)in the frame of the Nuclear medium cooling model
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Standard test: temperature vs. age
Kaminker et al. (2001)
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Log N – Log S
Log of flux (or number counts)
Lo
g o
f th
e n
um
ber
of
sou
rces
bri
gh
ter
than
th
e g
iven
flu
x
-3/2 sphere: number ~ r3
flux ~ r-2
-1 disc: number ~ r2
flux ~ r-2
calculations
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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
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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)
Model I. Yes C A Model II. No D B Model III. Yes C B Model IV. No C B Model V. Yes D B Model VI. No E B Model VII. Yes C B’ Model VIII.Yes C B’’ Model IX. No C A
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 Gaps
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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.
1P0 proton gap 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
We conclude that the two test complement each other
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)
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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)
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Evolution of NS: spin + magnetic field
Ejector → Propeller → Accretor → Georotator
Lipunov (1992) astro-ph/0101031
1 – spin-down2 – passage through a molecular cloud3 – magnetic field decay
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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
(back)
35
Model IX
No Pions Gaps from Takatsuka &
Tamagaki (2004) Ts-Tin from Blaschke,
Grigorian, Voskresenky (2004)
Can reproduce observed Log N – Log S
(back)
36
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)
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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
(back)
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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
(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)
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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
(back)
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Model VII
Pions Gaps from Yakovlev et
al. (2004), 3P2 neutron gap suppressed by 0.1.
1P0 proton gap suppressed by 0.5
Ts-Tin from Blaschke, Grigorian, Voskresenky (2004)
Cannot reproduce observed Log N – Log S
(back)
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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
(back)