Post on 19-Jan-2016
transcript
New adventures of UncatchablesNew adventures of Uncatchables
Sergei PopovSAI MSU
(astro-ph/0609275 and work in progress)
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Plan of the talkPlan of the talk
Intro. Pop. synthesis Some old results Two tests New improvements1. Initial distribution2. Mass spectrum and abundances3. ISM distribution Maps Age and distance distributions Where to search? Final conclusions
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Good old classicsGood old classicsGood old classicsGood old classics
The pulsar in the Crab nebulaThe pulsar in the Crab nebula A binary systemA binary system
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The new zoo of neutron starsThe new zoo of neutron starsThe new zoo of neutron starsThe new zoo of neutron starsDuring 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 reviewsMain reviewsMain reviewsMain reviews•NS basics: physics/0503245
•SGRs & AXPs: astro-ph/0406133
•Magnetars:-Observations AXPs astro-ph/0610304 SGR astro-ph/0608364- Theory 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 Труды ГАИШ том 72 (2003)
http://xray.sai.msu.ru/~polar/sci_rev/ns.html
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Isolated neutron stars population: Isolated neutron stars population:
in the Galaxy and at the backyard in the Galaxy and at the backyard
Isolated neutron stars population: Isolated neutron stars population:
in the Galaxy and at the backyard in the Galaxy and at the backyard INSs appear in many flavours
Radio pulsarsAXPsSGRsCCOsRINSsRRATs
Local population of young NSs is different (selection)
Radio pulsarsGeminga+RINSs
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Evolution of NSs. I.:temperatureEvolution of NSs. I.:temperature
[Yakovlev et al. (1999) Physics Uspekhi]
First papers on the thermalevolution 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
Evolution of neutron stars. II.:
rotation + magnetic fieldEjector → Propeller → Accretor → Georotator
See the book by Lipunov (1987, 1992)astro-ph/0101031
1 – spin down2 – passage through a molecular cloud3 – magnetic field decay
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Magnetorotational evolution of radio Magnetorotational evolution of radio pulsarspulsarsMagnetorotational evolution of radio Magnetorotational evolution of radio pulsarspulsars
Spin-down.Rotational energy is released.The exact mechanism is still unknown.
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Close-by radioquiet NSsClose-by radioquiet NSsClose-by radioquiet NSsClose-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 SevenMagnificent Seven
Name Period, sRX 1856 7.05RX 0720 8.39RBS 1223 10.31 RBS 1556 6.88?RX 0806 11.37RX 0420 3.45RBS 1774 9.44
Radioquiet (?)Close-byThermal emissionAbsorption featuresLong periods
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Population of close-by young NSsPopulation 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.
Where are the rest?UNCATCHABLES
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Population synthesis: ingredientsPopulation synthesis: ingredients
Birth rate of NSs Initial spatial distribution Spatial velocity (kick) Mass spectrum Thermal evolution Interstellar absorption Detector properties
A brief review on populationsynthesis in astrophysics canbe found in astro-ph/0411792
To build an artificial model
of a population of some astrophysical sources and
to compare the results ofcalculations with observations.
Task:
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Gould Belt : 20 NS Myr-1
Gal. Disk (3kpc) : 250 NS Myr-1
Arzoumanian et al. 2002
ROSAT
• Cooling curves by• Blaschke et al. • Mass spectrum
18°Gould BeltGould Belt
Population synthesis – I. Population synthesis – I.
© Bettina Posselt
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Solar vicinitySolar 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 BeltThe 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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Initial spatial distributionInitial spatial distribution
A very simple model for PS-I: The Gould Belt as a flat inclined disc pluscontribution from the galactic disc up to 3 kpc.
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Mass spectrum of NSsMass 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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Woosley et al. 2002
Progenitor mass vs. NS massProgenitor mass vs. NS massProgenitor mass vs. NS massProgenitor mass vs. NS mass
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Log N – Log S 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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Some results of PS-I:Log N – Log S and spatial distribution
Some results of PS-I:Log N – Log S and spatial distribution
(Popov et al. 2005 Ap&SS 299, 117)
More than ½ are in+/- 12 degrees from the galactic plane.19% outside +/- 30o
12% outside +/- 40o
Log N – Log S for close-by ROSAT NSs can be explained by standard cooling curves taking into account the Gould Belt.
Log N – Log S can be used as an additional
test of cooling curves
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Two testsTwo tests
Age – Temperature
&
Log N – Log S
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Standard test: temperature vs. Standard test: temperature vs. ageageStandard test: temperature vs. Standard test: temperature vs. ageage
Kaminker et al. (2001)
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Uncertainties in temperatureUncertainties in temperatureUncertainties in temperatureUncertainties in temperature
(Pons et al. astro-ph/0107404)
• Atmospheres (composition)• Magnetic field• Non-thermal contributions to the spectrum• Distance• Interstellar absorption• Temperature distribution
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Luminosity and age uncertaintiesLuminosity and age uncertaintiesLuminosity and age uncertaintiesLuminosity and age uncertainties
Page, Geppertastro-ph/0508056
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Log N – Log S as an additional testLog N – Log S as an additional testLog N – Log S as an additional testLog N – Log S as an additional test
Standard test: Age – TemperatureSensitive to ages <105 yearsUncertain age and temperatureNon-uniform sample
Log N – Log SSensitive 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)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 IModel I Pions. Gaps from Takatsuka & Tamagaki
(2004) Ts-Tin from Blaschke, Grigorian,
Voskresenky (2004)
Can reproduce observed Log N – Log S
(astro-ph/0411618)
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Model IIModel 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 IIIModel 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 IVModel 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 VModel 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 VIModel 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 VIIModel 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 VIIIModel 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 IXModel 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 constraintBrightness constraintBrightness constraintBrightness 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 SSensitivity of Log N – Log SSensitivity of Log N – Log SSensitivity 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
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Mass constraintMass constraintMass constraintMass 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
Phys. Rev .C (2006)nucl-th/0512098(published as a JINR preprint)
Cooling curves fromKaminker et al.
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Another attempt to test a set of Another attempt to test a set of models. models. Hybrid stars. Astronomy meets Hybrid stars. Astronomy meets QCDQCD
Another attempt to test a set of Another attempt to test a set of models. models. Hybrid stars. Astronomy meets Hybrid stars. Astronomy meets QCDQCD
We studied several models for hybrid stars applying all possible tests: - T-t- Log N – Log S- Brightness constraint- Mass constraint
nucl-th/0512098
We also tried to present examples when a model successfully passesthe Log N – Log S test, but fails to pass the standard T-t test or fails tofulfill the mass constraint.
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Model IModel I
Brightness - OKT-t - OKLog N – Log S - poorMass - NO
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Model IIModel II
Brightness - OK
T-t - No
Log N – Log S - OK
Mass - NO
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Model IIIModel III
Brightness - OK
T-t - poor
Log N – Log S - OK
Mass - NO
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Model IVModel IV
Brightness - OK
T-t - OK
Log N – Log S - OK
Mass - OK
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Resume for HySsResume for HySsResume for HySsResume for HySs
One model among four was able to pass all tests.
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1. Spatial distribution of progenitor stars
a) Hipparcos stars up to 500 pc[Age: spectral type & cluster age (OB
ass)]b) 49 OB associations: birth rate ~
Nstar
c) Field stars in the disc up to 3 kpc
Population sythesis – II.recent improvementsPopulation sythesis – II.recent improvements
Solid – new initial XYZDashed – Rbelt = 500 pcDotted – Rbelt = 300 pc
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Population sythesis – II.recent improvementsPopulation sythesis – II.recent improvements
2. New cross sections & abundances and new mass spectrum
Solid – new abundances, old massDotted – old abundances, old massDashed – new abundances, new mass
Low mass stars are treated followingastro-ph/0409422
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3. Spatial distribution of ISM (NH)
instead of :
now :
Population synthesis – II.recent improvementsPopulation synthesis – II.recent improvements
Dot-dashed and dot-dot-dashed linesRepresent two new models of theISM distribution.
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b= +90°
b= -90°
Popov et al. 2005
Count rate > 0.05 cts/s
OriSco OB
Cep?Per?
PSRs+
Geminga+
M7
PSRs-
First results: new mapsFirst results: new maps
Clearly several richOB associations startto dominate in thespatial distribution
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INSs and local surroundingINSs and local surrounding
De Zeeuw et al. 1999 Motch et al. 2006
Massive star population in the Solar vicinity (up to 2 kpc) is dominated by OB associations. Inside 300-400 pc the Gould Belt is mostly important.
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50 000 tracks, new ISM model50 000 tracks, new ISM model
AguerosChieregato
Candidates:
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Age and distance distributionsAge and distance distributions
Age
1 < cts/s < 10 0.1 < cts/s < 1 0.01 < cts/s < 0.1
Distance
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Where to search for more cowboys?Where to search for more cowboys?
We do not expect to find much more candidates at fluxes >0.1 cts/s.
Most of new candidates should be at fluxes 0.01< f < 0.1 cts/s.So, they are expected to be young NSs (<few 100 Mys) just outside the Belt.I.e., they should be in nearby OB associations and clusters.
Most probable candidates are Cyg OB7, Cam OB1, Cep OB2 and Cep OB3.Orion region can also be promising.
Name l- l+ b- b+ Dist., pc
Cyg OB7 84 96 -5 9 600-700
Cep OB2 96 108 -1 12 700
Cep OB3 108 113 1 7 700-900
Cam OB1 130 153 -3 8 800-900
0
10
-10
L=110 90130
(ads.gsfc.nasa.gov/mw/)
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Resume Resume
New more detailed population synthesis model for local population of isolated NS is made
New results provide a hint to search for new coolers. We predict that new objects can be identified at
0.01<cts/s<0.1 behind the Gould Belt in the directions of close-by rich OB associations, in particular Cep OB2.
These objects are expected to be younger and hotter than the Magnificent seven.
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The Magnificent Seven Vs. UncatchablesThe Magnificent Seven Vs. Uncatchables
Born in the Gould Belt.Bright. Middle-aged.Already observed.
Born behind the Belt.Dimmer. Younger.Wanted.
I thank all scientists with whom I collaborated during
different stages of work on INSs and had fruitful discussions:
D. Blaschke, M. Colpi, H. Grigorian, F. Haberl, V. Lipunov,
R. Neuhauser, B. Posselt, M. Prokhorov, A. Treves, J. Trumper, ….
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Main reviewsMain reviewsMain reviewsMain reviews•NS basics: physics/0503245
•SGRs & AXPs: astro-ph/0406133
•Magnetars:-Observations AXPs astro-ph/0610304 SGR astro-ph/0608364- Theory 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 Труды ГАИШ том 72 (2003)
http://xray.sai.msu.ru/~polar/sci_rev/ns.html
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Radio detectionRadio 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.
In 2006 Malofeev et al. reported radio detectionof another one.
(back)
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NS+NS binariesNS+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 2005)
(Back)