of cyclotron resonant scattering features Dr. Karl Remeis-Sternwarte Bamberg, Sternwartstraße 7, 96049 Bamberg, Germany Erlangen Centre for Astroparticle Physics (ECAP), Erwin-Rommel-Str. 1, 91058 Erlangen, Germany
Motivation: Measuring a neutron star s magnetic field Magnetic field variation 1 arbitrary flux [s 1 cm 2 kev 1 ] 0.1 0.01 10-3 10-4 10-5 10-6 10-7 10-8 0.05 0.06 0.07 0.08 Magnetic field strength [Bcrit] Absorption features Fundamental line and higher harmonics 12-B-12 rule: E cyc 12 B 12 kev Complex line shape 10-9 20 40 Energy [kev] 60 80
Outline 1 Accreting neutron star binary systems with cyclotron lines Origin of matter accreted to the neutron star The neutron star s magnetic field and its influence on the infalling plasma 2 Cyclotron emission from the accretion column
Accretion mechanisms Accretion column Accretion mechanisms in X-ray binary systems
Accretion mechanisms Accretion column Accretion mechanisms in X-ray binary systems WARNING Not to scale! R OB 7R sun Separation 25R sun
Accretion mechanisms Accretion column Accretion mechanisms in X-ray binary systems Kreykenbohm et al. (1999) Stellar Wind Vela X-1: B 3 10 12 G
Accretion mechanisms Accretion column Accretion mechanisms in X-ray binary systems L1 Truemper et al. (1978) Roche Lobe Overflow Her X-1: B 4 10 12 G
Accretion mechanisms Accretion column Accretion mechanisms in X-ray binary systems Santangelo et al. (1999) Be Accretion 4U 0115+63: B 1.4 10 12 G
Accretion mechanisms Accretion column Formation of an accretion column B B crit 4.4 10 13 G
Accretion mechanisms Accretion column Formation of an accretion column B Matter couples to magnetic field lines
Accretion mechanisms Accretion column Formation of an accretion column B Seed photon sources: Blackbody Bremsstrahlung Cyclotron emission etc...
of CRSF formation X-ray binaries B θ k
of CRSF formation X-ray binaries Resonance energy: ω n = 1 1 + 2nBsin 2 θ m sin 2 e θ B n θ k p
of CRSF formation X-ray binaries Resonance energy: ω n = 1 1 + 2nBsin 2 θ m sin 2 e θ e e B n p = p + k cos(θ) θ k p n
of CRSF formation X-ray binaries Resonance energy: ω n = 1 1 + 2nBsin 2 θ m sin 2 e θ e e e B e n p = p + k cos(θ) k θ k p n
of CRSFs
of CRSFs
of CRSFs Inject Photon Iterate Sample MFP and propagate photon Store photon Araya 99 vs. Schwarm 12 (Slab1-1) 20 Did the photon escape? yes 15 no Sample electron momentum Sample final Landau level Sample scattering angle Flux [kev 1 ] 10 20 15 τ = 1 10 4 τ = 3 10 4 Calculate final photon energy and electron momentum Next photon 10 τ = 1 10 3 0.08 τ = 3 10 3 0.08 0.02 0.04 0.06 0.02 0.04 0.06 Final Landau level >0? yes no Energy [MeV] Araya & Harding (1999) Sample decay Landau level Sample emission angle
of CRSFs Inject Photon Iterate Sample MFP and propagate photon Store photon Did the photon escape? yes no Sample electron momentum Sample final Landau level Sample scattering angle Calculate final photon energy and electron momentum Next photon Final Landau level >0? no yes Sample decay Landau level Schwarm et al. (2012) Sample emission angle
of CRSFs Inject Photon Harding 90 vs. Schwarm 12 10000 T = 5keV, ϑ = 85 Iterate Sample MFP and propagate photon Store photon 1000 100 Did the photon escape? yes 10 1 no Sample electron momentum Sample final Landau level Sample scattering angle Calculate final photon energy and electron momentum Next photon Thermally averaged scattering cross section [τt] 0.1 10000 1000 100 10 1 0.1 10000 T = 10keV, ϑ = 60 T = 50keV, ϑ = 60 Final Landau level >0? no 1000 100 yes Sample decay Landau level Sample emission angle 10 1 0.1 0.5 1 1.5 2 2.5 Energy [ωres] 3 3.5 4 Harding & Daugherty (1991)
Model parameters X-ray binaries cy, τ perp = 3.0E 04 τ Th, B = 0.04 B crit, T = 3 kev, µ = 0.00 6 5 4 3 Flux [kev 1 ] 2 1.5 1 0.8 0.6 0.5 0.4 20 40 Energy [kev] 60 80 100 120
Model parameters X-ray binaries cy, τ perp = 3.0E 04 τ Th, B = 0.06 B crit, T = 3 kev, µ = 0.00 6 5 4 B [B crit ]: 0.04 0.06 3 Flux [kev 1 ] 2 1.5 1 0.8 0.6 0.5 0.4 20 40 Energy [kev] 60 80 100 120
Model parameters X-ray binaries cy, τ perp = 3.0E 04 τ Th, B = 0.06 B crit, T = 15 kev, µ = 0.00 6 5 4 T [kev]: 3 15 3 Flux [kev 1 ] 2 1.5 1 0.8 0.6 0.5 0.4 20 40 Energy [kev] 60 80 100 120
Model parameters X-ray binaries cy, τ perp = 3.0E 04 τ Th, B = 0.06 B crit, T = 15 kev, µ = 0.50 6 5 4 µ: 0.0 0.5 3 Flux [kev 1 ] 2 1.5 1 0.8 0.6 0.5 0.4 20 40 Energy [kev] 60 80 100 120
Model parameters X-ray binaries sl10, τ para = 8.0E 04 τ Th, B = 0.06 B crit, T = 15 kev, µ = 0.50 6 5 4 geometry: cy sl10 3 Flux [kev 1 ] 2 1.5 1 0.8 0.6 0.5 0.4 20 40 Energy [kev] 60 80 100 120
Model parameters X-ray binaries sl11, τ para = 1.6E 03 τ Th, B = 0.06 B crit, T = 15 kev, µ = 0.50 6 5 4 geometry: sl10 sl11 3 Flux [kev 1 ] 2 1.5 1 0.8 0.6 0.5 0.4 20 40 Energy [kev] 60 80 100 120
Model parameters X-ray binaries 1 0.1 CRSF via RCL Green s function table 7/8 < µ < 8/8 4/8 < µ < 5/8 0.01 10-3 Flux [kev 1 ] 10-4 10-5 1 0.1 2/8 < µ < 3/8 0/8 < µ < 1/8 0.01 10-3 10-4 10-5 20 40 60 80 Energy [kev] 20 40 60 80 Isenberg et al. (1998)
Simulated spectrum Her X-1 with B&W 07 continuum 0.01 10-3 10-4 10-5 µ0 = 0.100 µ1 = 0.500 µ2 = 0.900 B&W 07 seed photons Blackbody radiation Bremsstrahlung Cyclotron radiation arbitrary flux 10-6 10-7 10-8 10-9 Optical Depth [τth] 1 10 4 10-10 10-11 10-12 10-13 Her X 1 B = 4.41 10 12 G Te = 6.00 kev M = 1.11 10 17 gs 1 r0 = 44 m 3 10 4 1 10 3 10-14 3 10 3 10-15 50 100 150 Energy [kev] Becker & Wolff (2007)
Simulated spectrum Her X-1 with B&W 07 continuum 40 60 Energy [kev] 80 100 120 140 Her X 1 B = 4.41 10 12 G Te = 6.00 kev 160 0.01 10-3 Ṁ = 1.11 10 17 gs 1 r0 = 44 m 10-4 τcyc = 10 10 4 τth 10-5 Flux [s 1 cm 2 kev 1 ] 0.1 0.01 10-3 10-4 10-5 r0 = 44m B ϑ = 60 sin(x) 10-6 10-7 10-8 10-9 Flux [s 1 cm 2 kev 1 ] 10-6 10-7 1 10 Energy [kev] 100 10-10 10-11
Cyclotron emission from the accretion column B B critical luminosity model (Becker et al., 2012)
Cyclotron emission from the accretion column B B critical luminosity model (Becker et al., 2012)
Cyclotron emission from the accretion column B B critical luminosity model (Becker et al., 2012) Reflection model (Poutanen et al., 2013)
Cyclotron emission from the accretion column B B B 3, T 3 B 2, T 2 B 1, T 1
Cyclotron emission from the accretion column B B B 3, T 3 B 2, T 2 B 1, T 1
Cyclotron emission from the accretion column B B E B 3, T 3 B 2, T 2 B 1, T 1 E
Summary CRSFs exhibit fundamental physics of accreting XRBs Completely new Monte Carlo code Comparison to data has just begun Get the model now! http://www.sternwarte.uni-erlangen.de/~schwarm/cyclomodel/ Thank you for your attention! Fritz.Schwarm@sternwarte.uni-erlangen.de
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