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

2 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

3 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 Note a recent discovery by Lyne et al. (submited to Nature, see later)

4 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

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

6 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.

7 Age-distance diagram (astro-ph/ ) A toy-model: a local sphere (R=300 pc) and a flat disk. Rate of NS formation in the sphere is 235 Myr -1 kpc -3 (26-27 NS in Myr in the whole sphere). Rate in the disc is 10 Myr -1 kpc -2 (280 NS in Myr up to 3 kpc).

8 More realistic age-dist. diagram Initial distribution from Popov et al Spatial evolution is not followed. For the line of “visibility” (solid line in the middle) I assume the limiting flux erg s -1 cm -2 and masses are <1.35 (Yakovlev et al. curves).

9 Realistic age-distance diagram Realistic initial distribution. Spatial evolution is taken into account. The line of “visibility” is drawn as the dotted line. Five curves correspond to 1, 4, 13, 20 and 100 NSs.

10 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

11 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

12 Distribution of open clusters (Piskunov et al. astro-ph/ )

13 Surface density of open clusters (Piskunov et al.)

14 Spatial distribution of close-by open clusters in 3D (Piskunov et al.) Grey contours show projected density distribution of young (log T<7.9) clusters.

15 Clusters and absorption (Piskunov et al.) Triangles – Gould Belt clusters.

16 Spatial distribution (Popov et al 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 +/- 30 o 12% outside +/- 40 o Lyne et al. reported transient dim radio sources with possible periodspossible periods about seconds in the galactic plane discovered in the Parkes survey (talk by A. Lyne in Amsterdam, august 2005; subm. to Nature).

17 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/ (masses of secondary objects in NS+NS)

18 Two tests Age – Temperature & Log N – Log S

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

20 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

21 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/

22 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

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

24 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

25 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

26 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

27 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

28 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

29 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

30 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

31 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

32 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!!!!

33 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/ )

34 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

35 THAT’S ALL. THANK YOU!

36 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.

37 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)

38 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

39 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)

40 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)

41 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)

42 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)

43 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)

44 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)

45 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)

46 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)

47 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)

48 NS+NS binaries Pulsar Pulsar mass Companion mass B B C B J J (PSR+companion)/2 J J J (David Nice, talk at Vancouver) (Back)Back

49 P-Pdot for new transient sources Lyne et al Submitted to Nature (I’m thankful to Prof. Lyne for giving me an opportunity to have a picture in advance) (back) Estimates show that there should be about sources of this type in the Galaxy