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New Test for Cooling Curves in Close-by Young Isolated Neutron Stars Population Synthesis

The presentation aims to introduce a novel test for cooling curves based on the Log N–Log S distribution in isolated neutron stars (NSs), specifically focusing on close-by young NSs. This test complements the standard temperature vs. age test and is crucial in understanding the diverse population of NSs, including radio pulsars, AXPs, SGRs, and more. The talk covers population synthesis, the concept of Log N–Log S, and its role in differentiating local NS populations. Various models of cooling curves are discussed, highlighting differences in pions, gaps for superfluid protons and neutrons, and Ts-Tin values. The study explores the mass spectrum, emission properties, and spatial distribution of NSs, addressing the unique characteristics of close-by young NSs compared to the general NS population in the galaxy.

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New Test for Cooling Curves in Close-by Young Isolated Neutron Stars Population Synthesis

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  1. 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

  3. 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

  4. 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

  5. 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

  6. Magnificent Seven Radioquiet (?) Close-by Thermal emission Long periods

  7. 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

  8. 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 population synthesis in astrophysics can be found in astro-ph/0411792

  9. 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

  10. 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

  11. 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

  12. 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

  13. Standard test: temperature vs. age Kaminker et al. (2001)

  14. Log N – Log S calculations -3/2 sphere: number ~ r3 flux ~ r-2 Log of the number of sources brighter than the given flux -1 disc: number ~ r2 flux ~ r-2 Log of flux (or number counts)

  15. 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

  16. 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

  17. 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: Absence or presence of pion condensate Different gaps for superfluid protons and neutrons Different Ts-Tin List of models (Blaschke et al. 2004) Pions Crust Gaps

  18. Model I • Pions. • Gaps from Takatsuka & Tamagaki (2004) • Ts-Tin from Blaschke, Grigorian, Voskresenky (2004) Can reproduce observed Log N – Log S

  19. 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

  20. 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

  21. 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

  22. 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

  23. 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

  24. 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

  25. 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

  26. Model IX • No Pions • Gaps from Takatsuka & Tamagaki (2004) • Ts-Tin from Blaschke, Grigorian, Voskresenky (2004) Can reproduce observed Log N – Log S

  27. 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!!!!

  28. 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)

  29. 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

  30. 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.

  31. THAT’S ALL. THANK YOU!

  32. 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)

  33. Evolution of NS: spin + magnetic field Ejector → Propeller → Accretor → Georotator 1 – spin-down 2 – passage through a molecular cloud 3 – magnetic field decay astro-ph/0101031 Lipunov (1992)

  34. 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)

  37. 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)

  38. 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)

  39. 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)

  40. 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)

  41. 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)

  42. 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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