solar vicinity, close-by young isolated nss, and tests of cooling curves sergei popov (sternberg...
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Solar vicinity, close-by young isolated NSs,and tests of cooling curves
Sergei Popov
(Sternberg Astronomical Institute)Co-authors: H.Grigorian, R. Turolla, D. Blaschke
ECT*, Trento, September 14, 2005
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Plan of the talk
Intro. Close-by NSs Age-Distance diagram Solar vicinity. Stars Spatial distribution Mass spectrum Two tests of cooling Brightness constraint Sensitivity of two tests Final conclusions
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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
Note a recent discoveryby Lyne et al. (submitedto Nature, see later)
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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.
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Age-distance diagram
(astro-ph/0407370)
A toy-model: a localsphere (R=300 pc)and a flat disk.
Rate of NS formationin the sphere is235 Myr-1 kpc-3
(26-27 NS in Myr inthe whole sphere).
Rate in the disc is10 Myr-1 kpc-2
(280 NS in Myr up to3 kpc).
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More realistic age-dist. diagram
Initial distributionfrom Popov et al. 2005.
Spatial evolution is notfollowed.
For the line of “visibility”(solid line in the middle)I assume the limitingflux 10-12 erg s-1 cm-2 and masses are <1.35(Yakovlev et al. curves).
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Realistic age-distance diagram
Realistic initial distribution.
Spatial evolution is takeninto account.
The line of “visibility” isdrawn as the dotted line.
Five curves correspond to1, 4 , 13, 20 and 100 NSs.
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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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Distribution of open clusters
(Piskunov et al. astro-ph/0508575)
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Surface density of open clusters
(Piskunov et al.)
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Spatial distribution of close-by open clusters in 3D
(Piskunov et al.)
Grey contours show projected densitydistribution of young(log T<7.9) clusters.
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Clusters and absorption
(Piskunov et al.)
Triangles – Gould Belt clusters.
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Spatial distribution
(Popov et al. 2005 Ap&SS 299, 117)
Shall we expect also Lyne’s objects from the Belt????YES!!! And they even have to be brighter (as they are closer).The problem – low dispersion.
More than ½ are in+/- 12 degrees from the galactic plane.
19% outside +/- 30o
12% outside +/- 40o
Lyne et al. reported transient dim radio sources with possible periodsabout seconds in the galactic plane discovered in the Parkes survey(talk by A. Lyne in Amsterdam, august 2005; subm. to Nature).
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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(masses of secondary objects in NS+NS)
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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 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 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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THAT’S ALL. THANK YOU!
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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
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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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)
38
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)
40
Model IX
No Pions Gaps from Takatsuka &
Tamagaki (2004) Ts-Tin from Blaschke,
Grigorian, Voskresenky (2004)
Can reproduce observed Log N – Log S
(back)
41
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)
42
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)
43
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)
44
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)
45
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)
46
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)
47
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)
48
NS+NS binaries
Pulsar Pulsar mass Companion mass
B1913+16 1.44 1.39B2127+11C 1.35 1.36B1534+12 1.33 1.35J0737-3039 1.34 1.25J1756-2251 1.40 1.18
(PSR+companion)/2
J1518+4904 1.35J1811-1736 1.30J1829+2456 1.25
(David Nice, talk at Vancouver)(Back)
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P-Pdot for new transient sources
Lyne et al. 2005Submitted to Nature
(I’m thankful to Prof. Lyne for giving me an opportunity to have a picture in advance)
(back)
Estimates show thatthere should be about 400 000sources of this type in the Galaxy