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/ )

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 J

6 Magnificent Seven NamePeriod, s RX RX RBS RBS RX RX RBS Radioquiet (?) Close-by Thermal emission Long periods

7 Population of close-by young NSs Magnificent seven Geminga and 3EG J Four radio pulsars with thermal emission (B ; B ; B ; B ) 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/

9 Solar vicinity Solar neighborhood is not a typical region of our Galaxy Gould Belt R= pc Age: Myrs 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 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/

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 Log of flux (or number counts) Log of the number of sources brighter than the given flux -3/2 sphere: number ~ r 3 flux ~ r disc: number ~ r 2 flux ~ r -2 calculations

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 R belt =500 pc astro-ph/

16 Log N – Log S as an additional test Standard test: Age – Temperature Sensitive to ages <10 5 years Uncertain age and temperature Non-uniform sample Log N – Log S Sensitive to ages >10 5 years (when applied to close-by NSs) Definite N (number) and S (flux) Uniform sample Two test are perfect together!!! astro-ph/

17 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 T s -T in Pions Crust Gaps

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

19 Model II No Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0.1 T s -T in from Tsuruta (1979) Cannot reproduce observed Log N – Log S

20 Model III Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0.1 T s -T in from Blaschke, Grigorian, Voskresenky (2004) Cannot reproduce observed Log N – Log S

21 Model IV No Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0.1 T s -T in from Blaschke, Grigorian, Voskresenky (2004) Cannot reproduce observed Log N – Log S

22 Model V Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0.1 T s -T in from Tsuruta (1979) Cannot reproduce observed Log N – Log S

23 Model VI No Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0.1 T s -T in from Yakovlev et al. (2004) Cannot reproduce observed Log N – Log S

24 Model VII Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by P 0 proton gap suppressed by 0.5 T s -T in from Blaschke, Grigorian, Voskresenky (2004) Cannot reproduce observed Log N – Log S

25 Model VIII Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by P 0 proton gap suppressed by 0.2 and 1 P 0 neutron gap suppressed by 0.5. T s -T in from Blaschke, Grigorian, Voskresenky (2004) Can reproduce observed Log N – Log S

26 Model IX No Pions Gaps from Takatsuka & Tamagaki (2004) T s -T in 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/ )

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 (> 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 Model I (YCA) Model II (NDB) Model III (YCB)Model Model III (YCB) Model Model IV (NCB) Model V (YDB) Model VI (NEB)ModelModel VI Model Model VII(YCB’) Model VIII (YCB’’) Model IX (NCA)ModelModel IX

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 J (RBS 1223) in the low-frequency band ( MHz) with the radio telescope in Pushchino. (back)

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

34 Model I Pions. Gaps from Takatsuka & Tamagaki (2004) T s -T in from Blaschke, Grigorian, Voskresenky (2004) Can reproduce observed Log N – Log S (back)

35 Model IX No Pions Gaps from Takatsuka & Tamagaki (2004) T s -T in from Blaschke, Grigorian, Voskresenky (2004) Can reproduce observed Log N – Log S (back)

36 Model III Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0.1 T s -T in from Blaschke, Grigorian, Voskresenky (2004) Cannot reproduce observed Log N – Log S (back)

37 Model II No Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0.1 T s -T in from Tsuruta (1979) Cannot reproduce observed Log N – Log S (back)

38 Model IV No Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0.1 T s -T in from Blaschke, Grigorian, Voskresenky (2004) Cannot reproduce observed Log N – Log S (back)

39 Model V Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0.1 T s -T in from Tsuruta (1979) Cannot reproduce observed Log N – Log S (back)

40 Model VI No Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0.1 T s -T in from Yakovlev et al. (2004) Cannot reproduce observed Log N – Log S (back)

41 Model VII Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by P 0 proton gap suppressed by 0.5 T s -T in from Blaschke, Grigorian, Voskresenky (2004) Cannot reproduce observed Log N – Log S (back)

42 Model VIII Pions Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by P 0 proton gap suppressed by 0.2 and 1 P 0 neutron gap suppressed by 0.5. T s -T in from Blaschke, Grigorian, Voskresenky (2004) Can reproduce observed Log N – Log S (back)