Joeri van Leeuwen An X-raydio switcheroo!

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1 Joeri van Leeuwen

2 Joeri van Leeuwen

3 Joeri van Leeuwen

4 Joeri van Leeuwen

5 Joeri van Leeuwen

6 Joeri van Leeuwen

7 Team Wim Hermsen Lucien Kuiper Dipanjan Mitra Jason Hessels Jelle de Plaa Joanna Rankin Ben Stappers Geoff Wright (SRON) (SRON) (NCRA) (ASTRON) (SRON) (U Vermont) (U Manchester) (U Sussex) +LOFAR Pulsar Working Group Anastasia Alexov, Thijs Coenen, Jean-Mathias Grießmeier, Tom Hassall, Aris Karastergiou, Evan Keane, Vlad Kondratiev, Michael Kramer, Masaya Kuniyoshi, Aris Noutsos, Maura Pilia, Maciej Serylak, Charlotte Sobey, Joris Verbiest, Patrick Weltevrede & Kimon Zagkouris

8 van Leeuwen et al in prep. LOFAR known source studies: Initial B data

9 van Leeuwen 2004 The basic ExB model (Ruderman & Sutherland 1975)

10 van Leeuwen et al in prep. The problem: subbeams move very slowly

11 Gil et al. (2006) One solution: a partially screen gap

12 Rankin et al. (2004) Partially screen gap, relation to mode changing

13 van Leeuwen & Timokhin (2012) Another solution: use the actual dv/dr Potential drop V (RS75)

14 van Leeuwen & Timokhin (2012) Another solution: use the actual dv/dr Potential drop V (LT12)

15 Interest in mode changes LOFAR pulsar work steadily ramping up towards 200 beam survey APERTIF PSR B exploiting ceases emitting PAFs + for regular tens of array days, layout for surveying then spins down ~50% less rapidly (Kramer et al. 2006). First multi-beam pulsar observations with test system already started Preparing for 600-beam transient/pulsar survey Several other pulsars display smaller changes in spin-down rate that correlate with changes in pulse shapes (Lyne et al. 2010). EMBRACE Aperture Array Proven to be excellent for multi-beam pulsar observations Allows for wide angles for timing, large FoVs for surveys SKA most compact core scenario 10,000 beams ~ P-OPS

16 The plan LOFAR 6 x 6 hours pulsar with work XMM, steadily LOFAR and ramping GMRT up towards 200 beam survey APERTIF exploiting PAFs + regular array layout for surveying First multi-beam pulsar observations with test system already started Preparing for 600-beam transient/pulsar survey EMBRACE Aperture Array Proven to be excellent for multi-beam pulsar observations Allows for wide angles for timing, large FoVs for surveys SKA most compact core scenario 10,000 beams ~ P-OPS

17 B with LOFAR and GMRT LOFAR pulsar work steadily ramping up towards 200 beam survey APERTIF exploiting PAFs + regular array layout for surveying First multi-beam pulsar observations with test system already started Preparing for 600-beam transient/pulsar survey EMBRACE Aperture Array Proven to be excellent for multi-beam pulsar observations Allows for wide angles for timing, large FoVs for surveys SKA most compact core scenario 10,000 beams ~ P-OPS Hermsen et al (Science 339, 436)

18 et al in prep. Large sample of B <-> Q mode transitions

19 Hermsen et al (Science 339, 436) Source is there in X-ray WIM s SLIDES HERE

20 Hermsen et al (Science 339, 436) But not always equally strong: B (Bright) Mode Q (Quiet) Mode

21 Hermsen et al (Science 339, 436) Pulsations!

22 Hermsen et al (Science 339, 436) Spectral behaviour (Q mode total)

23 Hermsen et al (Science 339, 436) Spectral behaviour (Q mode pulsed)

24 Hermsen et al (Science 339, 436) Spectral behaviour (Q mode, total, pulsed, unpulsed)

25 Hermsen et al (Science 339, 436) Spectral behaviour (B mode)

26 Hermsen et al (Science 339, 436) Spectral behaviour (B+Q mode)

27 Q mode pulsations are extra, and thermal +

28 Aligned rotator, viewing geometry considerations

29 Conclusions Modes identified in excellent LOFAR data, taken pre single-clock. First-ever correlated mode changes in X-ray and radio pulsar emission The Q and B modes have steady power-law emission Above that, the Q mode has pulsed thermal emission X-ray modes show the entire magnetic and current configuration changes Evidence for a Rapid Global Transformation of the Magnetosphere

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31 Spectral parameters Spectral parameters for the best model fits to the X-ray spectra. The column density N H has been fixed at 4.3 x cm -2. Mode total / pulsed Model BB (kt) kev PL index Γ (αe -Γ ) BB flux, unabs (0.5-8 kev) erg cm -2 s -1 PL flux, unabs (0.5-8 kev) erg cm -2 s -1 Χ 2 red / Q total BB+PL 0.277± ± ± ± / 20 Q pulsed BB 0.319± ± / 22 B total PL 2.29± ± / 10 dof

32 Pulsed fractions. Pulsed fractions of PSR B as a function of energy, defined as the ratio of the flux in the pulse profile over the total flux of the point source measured in the sky maps. Errors are 1 σ. Energy interval Pulsed kev fraction ± ± ± ± ± 0.53

33 Model fits Mode Q Q Q Q Q B B total / pulsed total total total pulsed pulsed total total Model BB+PL BB PL BB PL BB PL BB norm x ± ± ± ±0.16 BB (kt) kev 0.277± ± ± ±0.006 PL norm x ± ± ± ±0.21 PL, Γ (αe -Γ ) 2.60± ± ± ±0.16 F BB, unabsorbed 7.52± ± ± ± erg cm -2 s -1 L BB erg s ± ± ± ±0.4 F PL, unabsorbed 7.55± ± ± ± erg cm -2 s -1 L PL erg s ± ± ± ±0.5 Χ 2 red / dof 0.81 / / / / / / / 10

34 Figure by Jason Hessels B : Q and B mode from MHz B mode Q mode