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 (G) Field Magnetic – 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 (G) Field Magnetic – 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 τSNR~ 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, τc = 230 kyr Huge age discrepancy between ~ 32’ (263.2 pc@ 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 ± = 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 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 ± ⌧ (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 ± = 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 ~ 10 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 ± ⌧ (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 Overesmated – 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

6 Characteristic age @B 1+↵ (Colpi+2000) 10 = aB ↵ 4 10104 @t ⌧B 1/aB0 ) 2 ⌘ 102

(yr) 10 yr c

B(t)=B exp ( t/⌧ )(↵ = 0) ( 0 B 00 ) c 1010 τ 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 => “τc -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 (τB) • =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 τ 8 much more concentrated 10 to the plane 106 mag psr 104 ' (Tendulkar+2012) age Characteristic 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.