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Clues to the Formation and Evolution of Magnetars from X-Ray Observations of the Associated Supernova Remnants

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Clues to the Formation and Evolution of Magnetars from X-Ray Observations of the Associated Supernova Remnants Clues to the Formation and Evolution of Magnetars from X-ray observations of the associated Supernova Remnants! Toshio Nakano1, Kazuo Makishima1,2,3, Hideki Uchiyama4 and Teruaki Enoto2,5! 1The University of Tokyo, 2RIKEN, 3RESCEU,! 4Shizuoka University, 5NASA/GSFC! 0. Magnetars ! • Magnetic fields (B-field) of Neutron Stars (NSs) ! . 1016 – Widely distributed (108-15 G)! 1015 B = P P˙ – Characterize Types of NSs! 1014 13 p • Magnetar, Radio Pulsar, CCO…! 10 P 15 1012 ˙ • Magnetars, NSs with ~ 10 G ! = 2P 1011 ⌧ c th Magnetic Field (G) – Suzaku ~ Japanese 5 X-ray satellite ! 10 10 Radio Pulsar Magnetar ! !!(11 magnetars were observed)! 109 Bynary CCO High-B – Two-Component X-ray Spectra! 108 10-3 10-2 10-1 100 101 102 – Broadband Spectra evolution! Period (s) • Formation is not understood! – Supernova Remnants (SNR) = Clue ! • Temperature, Abundance, Energy, age …! Is there any clue in Mgnertar-hosting ! SNRs ?! ! 0. Magnetars ! • Magnetic fields (B-field) of Neutron Stars (NSs) ! . 1016 – Widely distributed (108-15 G)! 1015 B = P P˙ – Characterize Types of NSs! 1014 13 pXIS HXD • Magnetar, Radio Pulsar, CCO…! 10 P 15 1012 ˙ • Magnetars, NSs with ~ 10 G ! = 2P 1011 ⌧ c th Magnetic Field (G) – Suzaku ~ Japanese 5 X-ray satellite ! 10 10 Radio Pulsar Magnetar ! !!(11 magnetars were observed)! 109 Bynary Done by e.g., Enoto+2010 CCO High-B – Two-Component X-ray Spectra! 108 10-3 10-2 10-1 100 101 102 – Broadband Spectra evolution! Period (s) • Formation is not understood! – Supernova Remnants (SNR) = Clue ! • Temperature, Abundance, Energy, age …! Is there any clue in Mgnertar-hosting ! SNRs ?! ! 1. Supernova Remnants Associated with Magnetars! 1E2259+586/CTB109� 1E 1841-045/Kes73 SGR 0526-41/N49 AX J1845/G29.6+0.1 The Number of Associations Asso / NS TypiCal age (kyr) Pulsar 30/~2300 10-10,000 Magnetar Several /26 (21) < 10 SNR ~300 10 CTB109 has a large diameter => suitable 2. X-ray Observations of CTB109 with Suzaku! • Prototypical Magnetar/SNR association (Gregory & Fahlman 1980) ! – Distance: 3.2 ± 0.2 kpc (kothes+2012)! Previous works 30 ksec 40 ksec • CTB109! ) – Interaction with Giant Molecular Cloud! kpc – Middle age "SNR~ 13 kyr (Sasaki+2013)! • 1E 2259+586 ! . – P = 6.98 s, P = 4.8"10-13 ss-1 (Gavriil+2002)! 13 – B = 5.9"10 G, "c = 230 kyr! Huge age discrepancy between ~ 32’ (26 pc@ 3.2 ~ 32’ 30 ksec 40 ksec ⌧ ⌧ c(230 kyr) SNR(1.3kyr) • False color X-ray Image taken by Suzaku.! Suzaku Observations! 0.4-0.9 keV (red), 0.9-1.7 keV (green), – 1E 2259+596: 120 ksec (Enoto+2009)! 1.7-5.0 keV (blur) – CTB109 : 4 pointings (Nakano+ submitted )! 3. Spectral Analysis of CTB109 ! Mg(He-like) Characteristic emission lines Si(He-like) S(He-like) Ne(H-like) Ne(He-like) Fe(Ne-like) O(H-like) 3. Spectral Analysis of CTB109 ! Mg(He-like) 22 -2 Si(He-like) S(He-like) NH=0.88×10 cm Absorption kT = 0.61 keV Column density 2 12 -3 net = 1.0×10 s cm (fixed) Ne(H-like) Ne(He-like)kT1 = 0.27 keV n t= 0.5×1012 s cm-3 Fe(Ne-like) e -3 nshell = 1 – 3 cm O(H-like) Abundance : Solar #2/d.o.f = 983/961 Using Non Equilibrium Ionization model(NEI) ! Spectra require two plasma components (low and high kT) 3. Spectral Analysis of CTB109 ! Mg(He-like) 22 -2 Si(He-like) S(He-like) NH=0.88×10 cm Absorption kT = 0.61 keV Column density 2 12 -3 net = 1.0×10 s cm (fixed) Ne(H-like) Ne(He-like)kT1 = 0.27 keV n t= 0.5×1012 s cm-3 Fe(Ne-like) e -3 nshell = 1 – 3 cm O(H-like) Abundance : Solar #2/d.o.f = 983/961 Using Non Equilibrium Ionization model(NEI) ! Spectra require two plasma components (low and high kT) 4. Properties of the SN explosion CTB109! Ejecta (kT2 = 0.61 keV) 10 • Abundance pattern of the ejecta component is slightly over 1 solar. ! 1 Solar • Similar to theoretical O Ne Mg Si Fe model of M ~! 0.1 10 12 14 16 18 20 22 24 26 ! ! ! 15~25 M◉ (?)! Compared with Nomoto+1997 Atomic Number Heated ISM(Inter Stellar Medium) (kT1 = 0.27± 0.1 keV) R = 15 1pc 16 ± υ = k T = 470 30km/s 14 shell 3¯m B shell =(4.6 0.3) 10 km ± ± ⇥ 3 r ⇤ n0 = nshell/4=(0.25 0.8) cm υ 2 R 3 n − E =1.53 1042 shell shell 0 erg = (0.7 0.4) 1051 erg ex ⇥ km/s pc cm3 ± ⇥ ✓ ◆ ✓ ◆ ⇣ ⌘ 2 R ⌧SNR = = 13 1kyr ⌧c = 230 ky 5 υ ± ⌧ (Using Sedov-solution ) We reconfirmed the age discrepancy ⌧ ⌧ c SNR 4. Properties of the SN explosion CTB109! Ejecta (kT2 = 0.61 keV) 10 • Abundance pattern of the ejectaEjeCta component Abundace is slightly over 1 solar. ! 1 Solar • SimilarTypiCal Core-Collapse SNR to theoretical O Ne Mg Si Fe model of M ~! 0.1 10 12 14 16 18 20 22 24 26 ! ! ! 15~25 M◉ (?)! Compared with Nomoto+1997 Atomic Number Heated ISM(Inter Stellar Medium) (kT1 = 0.27± 0.1 keV) R = 15 1pc 16 ± υ = k T = 470 30km/s 14 shell 3¯m B shell =(4.6 0.3) 10 km ± ± ⇥ 3 r ⇤ n0 = nshell/4=(0.25 0.8) cm υ 2 R 3 n − E =1.53 1042 shell shell 0 erg = (0.7 0.4) 1051 erg ex ⇥ km/s pc cm3 ± ⇥ ✓ ◆ ✓ ◆ ⇣ ⌘ 2 R ⌧SNR = = 13 1kyr ⌧c = 230 ky 5 υ ± ⌧ (Using Sedov-solution ) We reconfirmed the age discrepancy ⌧ ⌧ c SNR 4. Properties of the SN explosion CTB109! Ejecta (kT2 = 0.61 keV) 10 • Abundance pattern of the ejectaEjeCta component Abundace is slightly over 1 solar. ! 1 Solar • SimilarTypiCal Core-Collapse SNR to theoretical O Ne Mg Si Fe model of M ~! 0.1 10 12 14 16 18 20 22 24 26 ! ! ! 15~25 M◉ (?)! Compared with Nomoto+1997 Atomic Number Heated ISM(Inter Stellar Medium) (kT1 = 0.27± 0.1 keV) R = 15 1pc 16 ± υ = k T = 470 30km/s 14 shell 3¯m B shell =(4.6 0.3) 10 km ± ± ⇥ 3 r 51 ⇤ n0 = nshell/4=(0.25 0.8) cm Explosion ~ 10υ 2 R 3 n erg − E =1.53 1042 shell shell 0 erg = (0.7 0.4) 1051 erg ex ⇥ km/s pc cm3 ± ⇥ 230 k(✓ ◆τC✓) > 13 ◆ ⇣ ky⌘ (τSNR) 2 R ⌧SNR = = 13 1kyr ⌧c = 230 ky 5 υ ± ⌧ (Using Sedov-solution ) We reconfirmed the age discrepancy ⌧ ⌧ c SNR 5. Age problem! ⌧c ⌧SNR special case for 1E 2259/CTB109 ? => Magnetars! Comparison of Age Estimations (NS-SNR) • Characteristic age! 1E2259+586/CTB109 – Assuming Constant B-field! OveresYmated – Valid for normal Pulsars! 5 10 2 n P !˙ B ! ⌧c / ) ⌘ (n 1) P˙ − 104 Concept of Characteristic age P B P P˙ P˙ Characteristic Age Characteristic Crab log / 103 p log t 103 104 105 Age of SNR t ⌧ 230 kyr is too old for CTB109, no longer observed c Caracteristic ages of Magnetars can be overestimated 6. Solving the age problem with B-field decay (1)! Example for $ dependence • For Magnetars ! 1012 Magnetic Field – 11 Const B B-Fields are decaying! 101015 – Overestimations are reasonable! 1010 (G) conversationally B (T) B • Hints to B-Field evolution! 1010129 • A simple B-field decay model! 108 108 Characteristic age @B 106 ! 1+↵ (Colpi+2000) = aB ↵ 4 10104 @t − ⌧B 1/aB0 ) 2 ⌘ 102 (yr) 10 yr c B(t)=B exp ( t/⌧ )(↵ = 0) ( 0 B 00 ) − c 1010 " B -2 2 B(x)= 0 (↵ = 0) 10-10 1/↵ 10-4 ) (1 ↵t/⌧B) 6 − 1010-62 10-4 10-2 100 102 104 Time (yr) (yr) 101 real t / c Which $ is suitable for Magnetar (1E 2259/CTB109) ? 100 10-6 10-4 10-2 100 102 104 106 Time (yr) 7. Solving age problem with B-field decay (2) ! • Applying B-field decay to 1E 2259+586/CTB109! – Conditions => “"c -B”, age of CTB109! Solutions B evolutions CTB109 4 B0 = 3.16e+14 G 17 α=2.0 3 (G) 1.0e+15 B 15 α=0.0 2 3.16e+16 log 13 1E 2259+586 1 (yr) 1.0e+16 2 B 0 10 ⌧ snr 3.16e+16 ⌧ -1 Preferred area → / 1 log c 10 1.0e+17 ⌧ 1E 2259+586/CTB109 -2 1 (hour) (Month) -6 -4 -2 0 24 0.0 0.5 1.0 1.5 2.0 2.5 Time log(yr) α (decay index) • $=0 → Rapid decay, unphysical long delay ("B) ! • $=2 → Moderate, needs too strong initial B-Field .. ?! 1.5 < $ < 1.8 is preferred 8. Magentars form a young population! • %c of magnetar have been greatly overestimated! – Magnetars must be younger than we thought so far! • Difference in spatial distributions strengthens this view! – Travel distance from the Galactic plane (Birth place) ∝ true age! -6 -4 -2 Galactic Spatial Distributions 10 10 10 – Magnetars appear to be! c Num/Century " 8 much more concentrated ! 10 to the plane! 106 υmag υpsr 104 ' (Tendulkar+2012) Characteristic age 102 100 101 102 statistically younger ! Number than others ! 10 Number 1 Nakano+2013! submited 1.0 0.0 1.0 D sin(Gb) kpC 9. Summary ! • We analyzed Suzaku X-ray data of the SNR CTB109 hosting magnetar AXP 1E 2259+586.! • Abundance profiles, and the explosion energy of CTB109 are not significantly different from those of typical SNRs.! • However, we reconfirmed the huge age discrepancy between characteristic age of 1E 2259+586 and the Sedov age of CTB109.! • Introducing B-field decay of 1E 2259+586, the age problem was solved.! • Magnetars are much younger than previously thought and can account for a considerable fraction of new-born NSs.! • Spatial distributions of magnetars are narrower than that of other pulsars, which provides further supporting evidence of young population view of magnetars.!.
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