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The Magnetar Primer

The Magnetar Primer. Shriharsh P. Tendulkar. S. R. Kulkarni P. B. Cameron. California Institute of Technology. The Neutron Star Household. Pulsars (1967) Soft Gamma Repeaters (1979 ) Recycled Pulsars (MSPs etc ) (1982) Isolated Neutron Stars (1992-1996)

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The Magnetar Primer

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

  2. The Neutron Star Household • Pulsars (1967) • Soft Gamma Repeaters (1979) • Recycled Pulsars (MSPs etc) (1982) • Isolated Neutron Stars (1992-1996) • Anomalous X-ray Pulsars (1995) • Compact Central Objects (around 2003) • RRaTs (2006) S. Tendulkar, RRI 2013

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

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

  5. AXPs • Anomalous X-ray Pulsars • LX ~ 1035-36 erg/s • Lrot ~1032 erg/s • No companions AXP 1E 2259+586 inside CTB 109 S. Tendulkar, RRI 2013

  6. SGRs • Soft Gamma Repeaters • Short bursts: • 1042 ergs/s • Giant flares • 2-500 x 1044 ergs • -29 mag! S. Tendulkar, RRI 2013

  7. What is a magnetar? • Highly magnetized NS • B ≈ 1015 G • Young • Slowly rotating (P ≈ 5-10 s) S. Tendulkar, RRI 2013

  8. What is a magnetar? SGR AXP 1 2 4 3 Scientific American 2003 R. Duncan S. Tendulkar, RRI 2013

  9. Reasons for high B • Spin down (1979 burst) • 8 sec in 104 years • Energetics • Variability • No baryons • Magnetic Containment S. Tendulkar, RRI 2013

  10. Magnetar vs Pulsar • Low B field ‘magnetar’ • SGR 0418+5729 • B~7 x 1012 G • Radio quiet, X-ray bright • Unsteady pulses, ratty Pdot • High B field pulsars • Few x 1013 G • Radio bright, X-ray quiet • Steady pulses, decline S. Tendulkar, RRI 2013

  11. Open Questions • Formation • B-field  Dynamo vs Fossil • Progenitors: • Mass, Spin, High B-field? • Age • Kinematics (~1000 km/s?) • SN energies • Evolution • Lifetime S. Tendulkar, RRI 2013

  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) S. Tendulkar, RRI 2013

  13. Astrometry S. Tendulkar, RRI 2013

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

  15. OIR Astrometry • Hubble Space Telescope • Large FoV • Stable Distortion • Diffraction Limited • Very precise astrometry! • ≈ 0.020 mas/yrover 7 years (Kallivayalil et al. 2013) S. Tendulkar, RRI 2013

  16. Challenges in AO astrometry • Small FoV (10-40”) • Anisoplanatism • Changing PSF • Variable Performance • Atmosphere dependent S. Tendulkar, RRI 2013

  17. Optimal Astrometry • Tip-tilt Anisoplanatism Sasiela 1994 Cameron et al. 2009 S. Tendulkar, RRI 2013

  18. Performance Palomar 5-m telescope Measurement Noise Tip-tilt Anisoplanatism Cameron et al 2009 S. Tendulkar, RRI 2013

  19. SGR 1900+14 • Giant flare: 27th Aug 1998 • d ≈ 12 kpc • OIR counterpart (Testa et al. 2008) Cluster of Massive Stars (Vrba et al. 2000) Turnoff mass ≈ 17 M (Davies et al. 2009) 40 arcsec S. Tendulkar, RRI 2013

  20. SGR 1806-20 • Giant flare: 27th Dec 2004 • d ≈ 15 kpc • OIR counterpart (Israel et al. 2005) Cluster of Massive Stars (Fuchs et al. 1999) Turnoff mass ≈ 50 M (Bibby et al. 2008) S. Tendulkar, RRI 2013

  21. AXP 4U 0142+61 • Brightest AXP • d ≈ 3kpc • Counterpart (Hulleman et al. 2000) • OIR pulsations (Kern & Martin 2002) • No association S. Tendulkar, RRI 2013

  22. AXP 1E 2259+586 • Center of CTB 109 • d ≈ 3 kpc • OIR counterpart (Hulleman et al. 2001) CTB 109 14 arcmin S. Tendulkar, RRI 2013

  23. Results S. Tendulkar, RRI 2013

  24. SGR 1900+14 Galactic Plane Measured Magnetar Velocity Expected Progenitor Velocity Galactic Rotation S. Tendulkar, RRI 2013

  25. SGR 1900+14 Age = 6 kyr TC = 0.9 kyr V = 130 km/s S. Tendulkar, RRI 2013

  26. SGR 1806-20 Towards Galactic Center V = 350 km/s S. Tendulkar, RRI 2013

  27. SGR 1806-20 Age = 650 ± 300 yr TC = 160 yr Tendulkar et al (2012) S. Tendulkar, RRI 2013

  28. AXP 1E 2259+586 V = 160 km/s Opposite to Galactic Center S. Tendulkar, RRI 2013

  29. AXP 1E 2259+586 Age = 14 kyr (Sasaki et al. 2013) Current Center of CTB 109 DENSE MOLECULAR CLOUD Center of explosion S. Tendulkar, RRI 2013 Tendulkar et al. in prep

  30. AXP 4U 0142+61 V = 100 km/s S. Tendulkar, RRI 2013

  31. AXP 4U 0142+61 Hunt for an association Tendulkar et al. in prep S. Tendulkar, RRI 2013

  32. Magnetar Kinematics S. Tendulkar, RRI 2013

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

  34. The NuSTAR Magnetar S. Tendulkar, RRI 2013

  35. Timeline • 24th April ‘13  SWIFT XRT brightening • 0.11 cts/s (1.3 x 1035 ergs/s) S. Tendulkar, RRI 2013

  36. Timeline • 24th April ‘13  SWIFT XRT brightening • 0.11 cts/s (1.3 x 1035 ergs/s) • 26th April ‘13  SWIFT BAT flare • 32 ms, 2500 cts/s S. Tendulkar, RRI 2013

  37. Timeline • 26thApril ‘13  SWIFT BAT flare • 32 ms, 2500 cts/s • 26th April ‘13  NuSTARToO 6 hrobs • 3.76 sec period S. Tendulkar, RRI 2013

  38. Timeline • 26th April ‘13  NuSTARToO 6 hrobs • 3.76 sec period • 29th April ‘13  Chandra position • 3” away from GC (0.1 pc) S. Tendulkar, RRI 2013

  39. Timeline • 29th April ‘13  Chandra position • 3” away from GC (0.1 pc) • 4th May ‘13  NuSTAR • 7 hrs • Pdot = 6 x 10-12 s/s • B ~ 1.5 x 1014 G S. Tendulkar, RRI 2013

  40. Timeline • 4th May ‘13  NuSTAR • 7 hrs • Pdot = 6 x 10-12 s/s • B ~ 1.5 x 1014 G • 6th May ’13  Paper to ApJL • Kaya Mori et al. S. Tendulkar, RRI 2013

  41. 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 S. Tendulkar, RRI 2013

  42. Astrometry S. Tendulkar, RRI 2013

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

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