Closeby young isolated neutron stars and black holes

Close-by young isolated neutron stars (and black holes) Sergey Popov (Sternberg Astronomical Institute)

Plan of the talk n NS: introduction n Close-by NSs n Population synthesis n Test of cooling curves n Close-by BHs n Final conclusions http: //xray. sai. msu. ru/~polar/html/kniga. html

Neutron stars: introduction n n Progenitors – massive stars Born in SN explosions R=10 km =1014 g/cm 3 (nuclear density) Appear in many flavours n n n Radio pulsars X-ray binaries AXPs SGRs CCOs RINSs

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

Evolution of NSs: temperature Yakovlev et al. (1999) Physics Uspekhi

Close-by radioquiet NSs n Discovery: n n RX J 1856. 5 -3754 Walter et al. (1996) Proper motion and distance: Kaplan et al. No pulsations Thermal spectrum Later on: six brothers

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-by Thermal emission Long periods

Population of close-by young NSs n Magnificent seven n Geminga and 3 EG J 1853+5918 n Four radio pulsars with thermal emission (B 0833 -45; B 0656+14; B 1055 -52; B 1929+10) n Seven older radio pulsars, without detected thermal emission. We need population synthesis studies of this population

Population synthesis: ingredients n Birth rate n Initial spatial distribution n Spatial velocity (kick) n Mass spectrum n Thermal evolution n Interstellar absorption n Detector properties A brief review on population synthesis in astrophysics can be found in astro-ph/04011792

Solar vicinity n Solar neighborhood is not a typical n n n 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

The Gould Belt n Poppel (1997) n R=300 – 500 pc n Age 30 -50 Myrs n Center at 150 pc from the Sun n Inclined respect to the galactic plane at 20 degrees n 2/3 massive stars in 600 pc belong to the Belt

Mass spectrum of NSs n Mass spectrum of local young NSs can be different from the general one (in the Galaxy) n Hipparcos data on nearby massive stars n Progenitor vs NS mass: Timmes et al. (1996); Woosley et al. (2002) astro-ph/0305599

Cooling of NSs n Direct URCA n Modified URCA n Neutrino bremstrahlung n Superfluidity n Exotic matter (pions, quarks, hyperons, etc. ) Kaminker et al. (2001)

Log N – Log S n Task: to understand the n n n 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

Log N – Log S as an additional test n Standard test: Age – Temperature n Sensitive to ages <105 years n Uncertain age and temperature n Non-uniform sample n Log N – Log S n Sensitive to ages >105 years n Definite N (number) and S (flux) n Uniform sample n Two test are perfect together!!! astro-ph/0411618

List of models (Blaschke et al. 2004) 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 n Model I. n n n n Pions. Model II. No pions. Model III. Pions. Model IV. No pions. Model V. Pions. Model VI. No pions. Model VII. Pions. Model VIII. Pions. Model IX. Pions.

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

Model II n No Pions n Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0. 1 n Ts-Tin from Tsuruta (1979) Cannot reproduce observed Log N – Log S

Model III n Pions n Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0. 1 n Ts-Tin from Blaschke, Grigorian, Voskresenky (2004) Cannot reproduce observed Log N – Log S

Model IV n No Pions n Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0. 1 n Ts-Tin from Blaschke, Grigorian, Voskresenky (2004) Cannot reproduce observed Log N – Log S

Model V n Pions n Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0. 1 n Ts-Tin from Tsuruta (1979) Cannot reproduce observed Log N – Log S

Model VI n No Pions n Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0. 1 n Ts-Tin from Yakovlev et al. (2004) Cannot reproduce observed Log N – Log S

Model VII n Pions n Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0. 1. 1 P proton gap 0 suppressed by 0. 5 n Ts-Tin from Blaschke, Grigorian, Voskresenky (2004) Cannot reproduce observed Log N – Log S

Model VIII n Pions n Gaps from Yakovlev et al. (2004), 3 P 2 neutron gap suppressed by 0. 1. 1 P 0 proton gap suppressed by 0. 2 and 1 P 0 neutron gap suppressed by 0. 5. n Ts-Tin from Blaschke, Grigorian, Voskresenky (2004) Can reproduce observed Log N – Log S

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

Resume n Magnificent Seven and other close-by NSs are genetically connected with the Gould Belt n Log N – Log S for close-by NSs can serve as a test for cooling curves n Two tests (Log. N–Log. S and Age-Temperature) are perfect together.

Black holes n Black holes are born from very massive progenitors n It is very difficult to observe as isolated BH: n n n Microlensing Weak accretion ……. ? n It is important to try to estimate at least approximate positions

Close-by BHs and runaway stars n 56 runaway stars inside 750 pc (Hoogerwerf et al. 2001) n Four of them have M > 30 Msolar Star Mass Velocity Age, km/s Myr ξ Per 33 65 1 HD 64760 ς Pup 25 -35 31 6 67 62 2 λ Cep 40 -65 74 4. 5 Prokhorov, Popov (2002)

Supernova explosion in a binary

ς Pup n Distance: 404 -519 pc n Velocity: 33 -58 km/s n Error box: 12 o x 12 o n NEGRET: 1

ξ Per n Distance: 537 -611 pc n Velocity: 19 -70 km/s n Error box: 7 o x 7 o n NEGRET: 1

Resume n Approximate positions of young close-by BHs can be estimated basing on data on massive runaway stars n For two cases we obtained relatively small error boxes n For HD 64760 and for λ Cep we obtained very large error boxes (40 -50 o) n Several EGRET sources inside

Final conclusions n We live in the region of the Galaxy enriched with n n young NSs and BHs NSs appear as radio pulsars, gamma and X-ray sources Local population teaches us that radio pulsars do not represent all young NSs Log N – Log S can be a good additional test for cooling curves of NSs Position of close-by isolated BHs can be roughly estimated for those originated from binary systems