No Longer! The Double Pulsar Maura McLaughlin West Virginia University 5 April 2012 Collaborators: Kramer (MPiFR), Stairs (UBC), Perera (WVU), Kim (WVU), Rosen (WVU), Lyutikov (Purdue), Lomiashvili (Purdue), Gourgouliatos (Purdue), Breton (Southampton), Kaspi (McGill), Freire (MPiFR), Burgay (Cagliari), Ferdman (Manchester), Possenti (Cagliari), Lyne (Manchester), Ransom (NRAO)

The Money Shot Kramer et al. in preparation

PulsarAB Period (ms) Stellar mass ( ⊙ ) Projected semi-major axis (lt-s) Characteristic age (Myr) Surface magnetic field strength (Gauss) 6x10 9 2x10 12 Energy loss rate due to spin-down (erg/s) 5800x x10 30 Distance (pc) Orbital inclination (degrees) Orbital period (hours) Eccentricity A B

Influence of B on A: Eclipses A is eclipsed for ~ 30 seconds per orbit. Occulting region of 0.05 lt-s; 10% of light- cylinder radius (~10 10 cm) of B. Can model eclipse shape to derive geometrical parameters of the system (α = 70 o, θ = 130 o ) and measure 5 o yr -1 rate of geodetic precession of B (Breton et al. 2008) 820 MHz McLaughlin et al Orbital phase (degrees) Pulsed flux density

Influence of B on A: Eclipses A is eclipsed for ~ 30 seconds per orbit. Occulting region of 0.05 lt-s; 10% of light- cylinder radius (~10 10 cm) of B. Pulsar B field is dipolar! 820 MHz Orbital phase (degrees) Pulsed flux density

Influence of A on B: Bright Phases Kramer and Stairs 2008 B bright at only two orbital phases. 820 MHz

B bright at only two orbital phases. Due to A distorting B’s magnetosphere (Lyutikov 2005). Influence of A on B: Bright Phases Kramer and Stairs MHz

Bright phases evolve due to periastron advance (17 o yr -1 ) and geodetic precession (5 o yr -1 ). Influence of A on B: Bright Phases Kramer and Stairs 2008 Light curves of B during BP1. Perera et al. 2010

B shows dramatic pulse profile changes across orbit and with time. March 2008: Bye Bye B  Geodetic Precession: Pulse Profiles Pulse profiles of B during BP1 Perera et al. 2010

We can fit the pulse profile evolution to a geometrical model. We find similar geometrical parameters as from eclipse model fitting (α = 70 o, θ = 130 o ). Emission beam is elliptical (a/b = 2.6) and only partially filled. Radio reappearance is expected to occur in Geodetic Precession: Pulse Profiles Perera et al. 2010

Bow shock at 4 x 10 9 cm (30% R LC ) from B. Can trace the magnetic field lines structure within this bow shock, given solved geometry. Will change with orbital phase and B spin phase. Can estimate a magnetic field of 6 x G, half of timing-derived value. Perera et al. submitted Influence of A on B: Emission Heights

Can estimate emission heights given magnetic field structure and shape of pulse profile. Perera et al. submitted

Application: NS-NS Inspiral Rates DP will merge in 85 Myr. Can now incporate selection effects for B. Kim et al. submitted

Application: NS-NS Inspiral Rates DP will merge in 85 Myr. There are roughly 1400(+4100,-900) DP-like systems in MW. Given 445 Mpc horizon distance for Advanced LIGO, we calculate a detection rate of 8(+11,-5) yr -1. Kim et al. submitted J0737 B1534 B1913

Influence of A on B: Drifting Features Single pulses from A Single pulses from B Drifting 820 MHz McLaughlin et al. 2004

Direct Evidence that B’s emission is modulated by A’s EM radiation! Influence of A on B: Drifting Features The drifting is a direct signature of the influence on the EM radiation from A on B! McLaughlin et al. 2004

Influence of A on B: Drifting Features Response Delay = Through a geometrical model (Freire et al. 2009, Rosen et al. in preparation), can fit for: 1) Rotation direction of A 2) Emission altitude in B, ε 3) Angle between A’s radio and EM beam, ϕ e

Through a geometrical model (Freire et al. 2009, Rosen et al. in preparation), can fit for: 1) Rotation direction of A likely in direction of orbit 2) Emission altitude in B, ε ~500 R NS (within the bow shock) 3) Angle between A’s radio and EM beam, ϕ e small and varying Influence of A on B: Drifting Features Response Delay =

Conclusions After nine years, the Double Pulsar is still providing new insights. We can fit B pulsar data with an elliptical, partially filled beam and can determine the geometrical parameters of the system. B is expected to reappear in We see evidence for the direct modulation of B pulsar emission through the EM field of A. We estimate minimum B emission heights of ~100 R NS through geometrical modeling and ~500 R NS through drift-band fitting. We estimate an Advanced LIGO NS-NS inspiral detection rate of 8(+11,-5) yr -1. More relativistic binaries essential for better statistics. Advances in timing and GR tests will come with improved B timing precision.