OPTICAL PULSE-PHASED PHOTOPOLARIMETRY OF PSR B0656+14

We have observed the optical pulse profile of PSR B0656+14 in 10 phase bins at a high signal-to-noise ratio, and have measured the linear polarization profile over 30% of the pulsar period with some significance. The pulse profile is double-peaked, with a bridge of emission between the two peaks, similar to gamma-ray profiles observed in other pulsars. There is no detectable unpulsed flux, to a 1 σ limit of 16% of the pulse-averaged flux. The emission in the bridge is highly (~100%) polarized, with a position angle sweep in excellent agreement with the prediction of the rotating vector model (RVM) as determined from radio polarization observations. We are able to account for the gross features of the optical light curve (i.e., the phase separation of the peaks) using both polar cap and outer gap models. Using the polar cap model, we are also able to estimate the height of the optical emission regions.

[1]  M. Disney,et al.  Discovery of Optical Signals from Pulsar NP 0532 , 1969, Nature.

[2]  C. Dermer,et al.  On the Spectra and Pulse Profiles of Gamma-Ray Pulsars , 1994 .

[3]  B. Peterson,et al.  Detection of optical pulses from the Vela pulsar , 1977, Nature.

[4]  R. Romani,et al.  $\gamma$-Ray Pulsars: Emission Zones and Viewing Geometries, A Computer Animation , 1994, astro-ph/9401045.

[5]  Russia.,et al.  Optical photometry of the PSR B0656+14 and its neighborhood , 2000, astro-ph/0009064.

[6]  Joseph K. Daugherty Alice K. Harding.  Gamma-ray pulsars: emission from extended polar cap cascades , 1995, astro-ph/9508155.

[7]  J. S. B. Dick,et al.  The optical polarization of the Crab Pulsar , 1988 .

[8]  A. Harding,et al.  Polar cap models of gamma-ray pulsars: Emision from single poles of nearly aligned rotators , 1994 .

[9]  R. Perna,et al.  Emission Spectra of Fallback Disks around Young Neutron Stars , 1999, astro-ph/9912297.

[10]  A. Shearer,et al.  Pulsed Optical Emission from PSR 0656+14 , 1997 .

[11]  J. Wardle,et al.  The linear polarization of quasi-stellar radio sources at 3.71 and 11.1 centimeters. , 1974 .

[12]  R. Romani.  Gamma-ray pulsars: Radiation processes in the outer magnetosphere , 1996 .

[13]  J. Kijak,et al.  Radio emission altitudes in pulsar magnetospheres , 1997 .

[14]  D. Thompson,et al.  Possible Evidence for Pulsed Emission of High-Energy Gamma Rays by PSR B0656+14 , 1996 .

[15]  A. G. Lyne,et al.  Multifrequency polarimetry of 300 radio pulsars , 1998 .

[16]  J. Wolfowitz,et al.  An Exact Test for Randomness in the Non-Parametric Case Based on Serial Correlation , 1943 .

[17]  J. Rankin.  Toward an empirical theory of pulsar emission. IV. Geometry of the core emission region , 1990 .

[18]  N. S. Schulz,et al.  Using the High-Resolution X-Ray Spectrum of PSR B0656+14 to Constrain the Chemical Composition of the Neutron Star Atmosphere , 2002, astro-ph/0203463.

[19]  Emission Beam Geometry of Selected Pulsars Derived from Average Pulse Polarization Data , 2000, astro-ph/0009266.

[20]  J. Middleditch,et al.  Optical pulsations in the Large Magellanic Cloud remnant 0540–69.3 , 1985, Nature.