1 / 37

Great unification for neutron stars: The last element?

Great unification for neutron stars: The last element?. Sergei Popov SAI MSU. Diversity of young neutron stars. Young isolated neutron stars can appear in many flavors: Radio pulsars Compact central X-ray sources in supernova remnants. Anomalous X-ray pulsars Soft gamma repeaters

edan
Download Presentation

Great unification for neutron stars: The last element?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Great unification for neutron stars: The last element? Sergei PopovSAI MSU

  2. Diversity of young neutron stars • Young isolated neutron starscan appear in many flavors: • Radio pulsars • Compact central X-ray sources • in supernova remnants. • Anomalous X-ray pulsars • Soft gamma repeaters • The Magnificent Seven & Co. • Transient radio sources (RRATs) • …………………… Kaplan 0801.1143 “GRAND UNIFICATION” is welcomed! (Kaspi 2010) See a review in 1111.1158

  3. NS birth rate [Keane, Kramer 2008, arXiv: 0810.1512]

  4. RRATs properties 19 with P-PdotRRATs seem to besimilar to PSRs 1109.6896

  5. Most of RRATs are PSRs? Vela PSR J1646–6831 J1647–36 J1226–32 1212.1716

  6. Transient radiopulsar PSR J1846-0258 P=0.326 sec B=5 1013 G Among all rotation poweredPSRs it has the largest Edot.Smallest spindown age (884 yrs). The pulsar increased its luminosity in X-rays. Increase of pulsed X-ray flux. Magnetar-like X-ray bursts (RXTE). Timing noise. See additional info about this pulsar at the web-site http://hera.ph1.uni-koeln.de/~heintzma/SNR/SNR1_IV.htm 0802.1242, 0802.1704

  7. Chandra: Oct 2000 June 2006 Bursts from the transient PSR Gavriil et al. 0802.1704

  8. Weak dipole field magnetar Spin period of a neutron star grows. The rate of deceleration is related to the dipole magnetic field. Measuring the spin-down rate we measure the field. The source is a soft gamma-rayrepeater: SGR0418+5729 P=9.1 s The straight line in the plotcorresponds to a constantspin periods: i.e. no spin-down 200 400 B<7.5 1012G arXiv: 1010.2781 However, spectral modeling (arXiv: 1103.3024) suggests that the surface field is~1014 G.This can indicate a strongly non-dipolar field.

  9. Another low field magnetar Swift J1822.3-1606 (SGR 1822-1606) P=8.44 sB=3-5 1013 G 1204.1034 1203.6449 New data: 1211.7347

  10. Quiescent magnetar Normally magnetars are detected via theirstrong activity: gamma-ray bursts orenhanced X-ray luminosity. This one was detected in radio observations The field is estimated to be B~3 1014G It seems to be the first magnetar to be Detected in a quiescent state. PSR J1622–4950 was detected in a radio survey As a pulsar with P=4.3 s. Noisy behavior in radio Chandra ATCA (see a review on high-B PSRs in 1010.4592 arXiv: 1007.1052

  11. A transient magnetar? PSR J1622–4950 X-ray flux is decayingfor several years.Probably, the sourcewas active years before. G333.9+0.0 SNR ? 1203.2719 See also 1204.2045

  12. Magnetars bursting activity due to decay In the field decay model it is possible to study burst activity.Bursts occur due to crust cracking. The decaying fieldproduce stresses in the crust that are not compensated byplastic deformations. When the stress level reaches acritical value the crust cracks, and energy can be released.At the moment the model is very simple, but this justthe first step. 1101.1098

  13. Magnetic field decay A model based on the initial field-dependent decay can provide an evolutionary link between different populations (Pons et al.). Toroidal field is very importantfor magnetar activity! arXiv: 0710.4914 (Aguilera et al.)

  14. Magnetic field decay and links arXiv: 0710.4914 (Aguilera et al.) It is possible to use HMXBsto test models of field decayon time scale >1 Myr(Chashkina, Popov 2012) 1112.1123

  15. Extensive population synthesis We want to make extensive population synthesis studies using as many approaches as we can to confront theoretical modelswith different observational data • Log N – Log S for close-by young cooling isolated neutron stars • Log N – Log L distribution for galactic magnetars • P-Pdot distribution etc. for normal radio pulsars MNRAS 401, 2675 (2010)arXiv: 0910.2190 See a review of the population synthesis technique inPopov, Prokhorov Physics Uspekhi vol. 50, 1123 (2007) [ask me for the PDF file, if necessary - it is not in the arXiv]

  16. P-Pdot tracks Kaplan & van Kerkwijk arXiv: 0909.5218 Color on the track encodessurface temperature. Tracks start at 103 years,and end at ~3 106 years. 0910.2190

  17. The best model: PSRs+magnetars+M7 Best model: <log(B0/[G])>= 13.25, σlogB0=0.6, <P0>= 0.25 s, σP0 = 0.1 s

  18. CCOs For two sources there are strong indications for large (>~100 msec) initial spin periods and low magnetic fields:1E 1207.4-5209 in PKS 1209-51/52 andPSR J1852+0040 in Kesteven 79 [see Halpern et al. arxiv:0705.0978] Puppis A Recent list in: 0911.0093

  19. Sample of NSs+SNRs 30 pairs: PSR+SNRPopov, Turolla arXiv: 1204.0632Ap&SS

  20. B vs. P0 All presented estimatesare made for standardassumptions: n=const=3.So, field is assumed to beconstant, as well as the anglebetween spin and magnetic axis.Crosses – PSRs in SNRs (or PWN) with ages justconsistent with spin-down ages.We assume that P0<0.1P 1204.0632

  21. Checking gaussian The data we have is not enoughto derive the shape of theP0 distribution.However, we can excludevery wide and very narrowdistributions, and also wecan check if some specificdistributions are compatible withour results.Here we present a test fora gaussian distribution,which fits the data.Still, we believe that thefine tuning is prematurewith such data. P0=0.1 s; σ=0.1 s

  22. Checking flat distrbution Flat between 0.001 and 0.5 s.Very wide distributionsin general do not fit the data we have.

  23. Anti-magnetars Note, that there is no roomfor antimagnetars from thepoint of view of birthratein many studies of differentNS populations. New results 1301.2717Spins and derivative aremeasured forPSR J0821-4300 and PSR J1210-5226 Ho 1210.7112

  24. Evolution of CCOs Popov et al. MNRAS 2010 Halpern, Gotthelf Chashkina,Popov 2012 PSRs+Magnetars+Close-by coolers CCOs HMXBs B B 1010 1012 1011 1013 Among young isolated NSs about 1/3 can be related to CCOs.If they are anti-magnetars, then we can expect that 1/3 of NSsin HMXBs are also low-magnetized objects.They are expected to have short spin periods <1 sec.However, there are no many sources with such properties.The only good example - SAX J0635+0533. An old CCO?Possible solution: emergence of magnetic field (see physics in Ho 2011, Vigano, Pons 2012).

  25. Observations vs. theory We use observations of Be/X-ray binaries in SMC to derive magnetic field estimates, and compare themwith prediction of the Pons et al. model. Chashkina, Popov (2012)

  26. Where are old CCOs? Yakovlev, Pethick 2004 According to cooling studies they have to be bright till at least 105 years.But only one candidate (2XMM J104608.7-594306 Pires et al.) to be a low-B cooling NSis known (Calvera is also a possible candidate).We propose that a large set of data on HMXBs and cooling NSsis in favour of field emergence on the time scale 104≤ τ ≤ 105 years (arXiv:1206.2819).Some PSRs with thermal emission for which additional heating was proposed can be descendants of CCOs with emerged field.

  27. Emerging field: modeling 1D model of field emergence Dashed – crustal, dotted – core field Ho 2011

  28. Another model 2D model with field decayOhmic diffusion dominates in field emergence, but Hall termalso can be important. Calculations confirm thatemergence on the time scale 103-105 years is possible. B0p=1014 G Vigano, Pons 2012

  29. Espinoza et al. arXiv: 1109.2740 Emerged pulsars in the P-Pdot diagram Emerged pulsars are expected to haveP~0.1-0.5 secB~1011-1012 GNegative braking indicesor at least n<2. About 20-40 of such objects are known. Parameters of emerged PSRs: similar to “injected” PSRs (Vivekanand, Narayan, Ostriker). The existence of significant fractionof “injected” pulsars formallydo not contradict recent pulsar current studies(Vranesevic, Melrose 2011). Part of PSRs supposed to be born withlong (0.1-0.5 s) spin periods can bematured CCOs.

  30. Wide initial spin period distribution Based on kinematic ages. Mean age – few million years.Note, that in Popov & Turolla (2012) only NSs in SNRswere used, i.e. the sample is much younger!Can it explain the difference& 1301.1265

  31. Magnetic field decay and P0 One can suspect that magnetic field decay can influence the reconstructionof the initial spin period distribution. Exponential field decay with τ=5 Myrs. <P0>=0.3 s, σP=0.15 s; <log B0/[G]>=12.65, σB=0.55 τ<107 yrs, 105<t 105<t<107 yrs Igoshev, Popov 2013

  32. Real vs. reconstructed P0 How long reconstructed initial periodschanged due to not taking into accountthe exponential field decay Igoshev, Popov 2013

  33. Synthetic populations Exponential decay Constant field Igoshev, Popov 2013

  34. Fitting the field decay Igoshev, Popov 2013

  35. Another option: emerging field The problem is just with few (6)most long-period NSs. Is it possible to hide them when they are young, and make them visibleat the age ~few million years? Yes! Emerging magnetic field!!!Then we need correlations betweendifferent Igoshev, Popov 2013

  36. Conclusions • Evolutionary links between different types of NSs are established • It was possible to describe three INS populations in one model with decaying magnetic field with unique gaussian initial B distribution • It is suggested that CCOs have non-trivial evolution with emerging field • Data on HMXBs suggest that the time scale for field emergence is <105 yrs • Comparison of the data on initial spin periods based on populations of different ages provides arguments in favour of field decay or/and emerging field

More Related