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The Magnetar Primer Shriharsh P. Tendulkar California Institute of Technology S. R. Kulkarni P. B. Cameron.

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Presentation on theme: "The Magnetar Primer Shriharsh P. Tendulkar California Institute of Technology S. R. Kulkarni P. B. Cameron."— Presentation transcript:

1 The Magnetar Primer Shriharsh P. Tendulkar California Institute of Technology S. R. Kulkarni P. B. Cameron

2 The Neutron Star Household Pulsars (1967) Soft Gamma Repeaters (1979) Recycled Pulsars (MSPs etc) (1982) Isolated Neutron Stars ( ) Anomalous X-ray Pulsars (1995) Compact Central Objects (around 2003) RRaTs (2006) 13/02/13S. Tendulkar, RRI 20132

3 Where does everything fit? 13/02/13S. Tendulkar, RRI 2013 SGRs AXPs INSs RRaTs Standard Issue Pulsars MSPs 3

4 Where does everything fit? 13/02/13S. Tendulkar, RRI 2013 Magnetic Field Powered Rotation Powered “Accretion” Powered 4

5 AXPs Anomalous X-ray Pulsars L X ~ erg/s L rot ~10 32 erg/s No companions 13/02/13S. Tendulkar, RRI 2013 AXP 1E inside CTB 109 5

6 SGRs Soft Gamma Repeaters Short bursts: – ergs/s Giant flares – x ergs – -29 mag! 13/02/13S. Tendulkar, RRI 20136

7 What is a magnetar? Highly magnetized NS – B ≈ G – Young – Slowly rotating (P ≈ 5-10 s) 13/02/13S. Tendulkar, RRI 20137

8 What is a magnetar? 13/02/13S. Tendulkar, RRI Scientific American 2003 R. Duncan AXP SGR 8

9 Reasons for high B Spin down (1979 burst) – 8 sec in 10 4 years Energetics – Variability – No baryons Magnetic Containment 13/02/13S. Tendulkar, RRI 20139

10 Magnetar vs Pulsar Low B field ‘magnetar’ – SGR – B~7 x G Radio quiet, X-ray bright Unsteady pulses, ratty Pdot High B field pulsars – Few x G Radio bright, X-ray quiet Steady pulses, decline 13/02/13S. Tendulkar, RRI

11 Open Questions Formation – B-field  Dynamo vs Fossil – Progenitors: Mass, Spin, High B-field? – Age – Kinematics (~1000 km/s?) – SN energies Evolution – Lifetime 13/02/13S. Tendulkar, RRI

12 Wider Relevance Neutron Star census – Millions might be floating around? – Star formation history etc. Fraction of short-hard GRBs (Ofek et al) – Rate of NS-NS mergers Energetic supernovae (Kasen & Bildsten 2010) 13/02/13S. Tendulkar, RRI

13 Astrometry 13/02/13S. Tendulkar, RRI

14 Why Astrometry? Kinematics – Comparison to other NS groups Ages – Model free Progenitors/Birth-places 13/02/13S. Tendulkar, RRI 2013 Challenges: – Can’t work in X-rays – Very few radio/IR counterparts 14

15 OIR Astrometry Hubble Space Telescope – Large FoV – Stable Distortion – Diffraction Limited Very precise astrometry! – ≈ mas/yr over 7 years (Kallivayalil et al. 2013) 13/02/13S. Tendulkar, RRI

16 Challenges in AO astrometry Small FoV (10-40”) Anisoplanatism – Changing PSF Variable Performance – Atmosphere dependent 13/02/13S. Tendulkar, RRI

17 Optimal Astrometry Tip-tilt Anisoplanatism 13/02/13S. Tendulkar, RRI 2013 Sasiela 1994 Cameron et al

18 Optimal Astrometry Use covariance information Position: p i = W  d i d i = [x 0 -x i, x 1 -x i … y N -y i ] T for each epoch Choose weights W for lst. sq. optimization – Same weights for all epochs 13/02/13S. Tendulkar, RRI

19 Performance 13/02/13S. Tendulkar, RRI 2013 Palomar 5-m telescope Cameron et al 2009 Measurement NoiseTip-tilt Anisoplanatism 19

20 SGR Giant flare: 27 th Aug 1998 d ≈ 12 kpc OIR counterpart (Testa et al. 2008) 13/02/13S. Tendulkar, RRI arcsec Cluster of Massive Stars (Vrba et al. 2000) Turnoff mass ≈ 17 M  (Davies et al. 2009) 20

21 SGR Giant flare: 27 th Dec 2004 d ≈ 15 kpc OIR counterpart (Israel et al. 2005) 13/02/13S. Tendulkar, RRI 2013 Cluster of Massive Stars (Fuchs et al. 1999) Turnoff mass ≈ 50 M  (Bibby et al. 2008) 21

22 AXP 4U Brightest AXP d ≈ 3 kpc Counterpart (Hulleman et al. 2000) OIR pulsations (Kern & Martin 2002) No association 13/02/13S. Tendulkar, RRI

23 AXP 1E Center of CTB 109 d ≈ 3 kpc OIR counterpart (Hulleman et al. 2001) 13/02/13S. Tendulkar, RRI arcmin CTB 109

24 Results 13/02/13S. Tendulkar, RRI

25 SGR /02/13S. Tendulkar, RRI 2013 Galactic Rotation Expected Progenitor Velocity Measured Magnetar Velocity Galactic Plane 25

26 SGR /02/13S. Tendulkar, RRI 2013 Age = 6 kyr T C = 0.9 kyr V = 130 km/s 26

27 SGR /02/13S. Tendulkar, RRI 2013 Towards Galactic Center V = 350 km/s 27

28 SGR /02/13S. Tendulkar, RRI 2013 Tendulkar et al (2012) Age = 650 ± 300 yr T C = 160 yr 28

29 SGR /02/13S. Tendulkar, RRI

30 AXP 1E /02/13S. Tendulkar, RRI 2013 V = 160 km/s Opposite to Galactic Center 30

31 AXP 1E /02/13S. Tendulkar, RRI 2013 Current Center of CTB 109 Age = 14 kyr (Sasaki et al. 2013) Center of explosion DENSE MOLECULAR CLOUD Tendulkar et al. in prep 31

32 AXP 4U /02/13S. Tendulkar, RRI 2013 V = 100 km/s 32

33 AXP 4U /02/13S. Tendulkar, RRI 2013 Hunt for an association Tendulkar et al. in prep 33

34 Magnetar Kinematics MagnetarV tan (km/s)AssociationMethodReference AXP 1E 1810−197212±35 –VLBIHelfand et al (2007) AXP 1E ±120SNR G VLBIDeller et al (2012) SGR ±30ClusterLGSAOTendulkar et al (2012) SGR ±100ClusterLGSAOTendulkar et al (2012) AXP 1E ±17SNR CTB 109LGSAOTendulkar et al (subm) AXP 4U ±26 –LGSAOTendulkar et al (subm) 13/02/13S. Tendulkar, RRI

35 Magnetar Kinematics 13/02/13S. Tendulkar, RRI 2013 Tendulkar et al. in prep Matches the velocity distribution of normal pulsars (Hobbs 2005) 35

36 The NuSTAR Magnetar 13/02/13S. Tendulkar, RRI

37 Timeline 24 th April ‘13  SWIFT XRT brightening – 0.11 cts/s (1.3 x ergs/s) 13/02/13S. Tendulkar, RRI

38 Timeline 24 th April ‘13  SWIFT XRT brightening – 0.11 cts/s (1.3 x ergs/s) 26 th April ‘13  SWIFT BAT flare – 32 ms, 2500 cts/s 13/02/13S. Tendulkar, RRI

39 Timeline 26 th April ‘13  SWIFT BAT flare – 32 ms, 2500 cts/s 26 th April ‘13  NuSTAR ToO 6 hr obs – 3.76 sec period 13/02/13S. Tendulkar, RRI

40 Timeline 26 th April ‘13  NuSTAR ToO 6 hr obs – 3.76 sec period 29 th April ‘13  Chandra position – 3” away from GC (0.1 pc) 13/02/13S. Tendulkar, RRI

41 Timeline 29 th April ‘13  Chandra position – 3” away from GC (0.1 pc) 4 th May ‘13  NuSTAR – 7 hrs – Pdot = 6 x s/s – B ~ 1.5 x G 13/02/13S. Tendulkar, RRI

42 Timeline 4 th May ‘13  NuSTAR – 7 hrs – Pdot = 6 x s/s – B ~ 1.5 x G 6 th May ’13  Paper to ApJL – Kaya Mori et al. 13/02/13S. Tendulkar, RRI

43 Implications Very similar to other magnetars Probably born in O/WR stars – 6 Myr old  40 M  More evidence for “transient” magnetars – Link to high-B pulsars 13/02/13S. Tendulkar, RRI

44 Astrometry 13/02/13S. Tendulkar, RRI

45 Galactic Rotation 13/02/13S. Tendulkar, RRI 2013 No quasars – Absolute astrometry is challenging Model galactic rotation – Along line of sight – SDSS stellar density – Estimate bulk motion Progenitor Velocity 45


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