160 likes | 285 Views
Towards an Understanding of the Isolated Neutron Star RX J1856.5-3754. Wynn Ho Kavli Institute for Particle Astrophysics and Cosmology Stanford University. 2005 Hubble Fellows Symposium – 7-8 April 2005. (Yakovlev & Pethick 2004). Physics from Neutron Star Surface Emission.
E N D
Towards an Understanding of the Isolated Neutron Star RX J1856.5-3754 Wynn Ho Kavli Institute for Particle Astrophysics and Cosmology Stanford University 2005 Hubble Fellows Symposium – 7-8 April 2005
(Yakovlev & Pethick 2004) Physics from Neutron Star Surface Emission • Equation of state • Thermal evolution • Surface composition • Magnetic field
( ) Lattimer & Prakash 2004, Courtesy of Page Neutron Star Surface Emission • Atmosphere scale height H 1 cm << R • Emission is anisotropic and polarized in magnetic field • Vacuum polarization important at B > BQ = me2c3/eℏ = 4.4 1013 G • Atoms bound by magnetic field
RX J1856.5-3754 • Thermal emission • No spectral features • BB underpredicts optical by 7 • Atmosphere overpredicts by >> 1 • Two blackbodies • kT=63 eV, R=4.4 km • kT=26 eV, R=18.2 km • No X-ray pulsations (1.3% limit) (Burwitz et al. 2003)
RX J1856.5-3754 Model Spectra/ Observations
RX J1856.5-3754 • Thermal emission • No spectral features • BB underpredicts optical by 7 • Atmosphere overpredicts by >> 1 • Two blackbodies • kT=63 eV, R=4.4 km • kT=26 eV, R=18.2 km • No X-ray pulsations (1.3% limit) (Burwitz et al. 2003)
RX J1856.5-3754 Model Spectra/ Observations
105 Condensed Iron Surface Emission
105 Condensed Iron Surface Emission
Model Spectra/Observations RX J1856.5-3754
Collaborators David L. Kaplan (Massachusetts Institute of Technology) Philip Chang (University of California, Santa Barbara) Matthew van Adelsberg and Dong Lai (Cornell University) Alexander Y. Potekhin (Ioffe Physico-Technical Institute) Gilles Chabrier (Ecole Normale Superieure de Lyon, CRAL)
RX J1856.5-3754 Effect of Redshift
Dim Isolated Neutron Stars (XMM-van Kerkwijk 2003) • Radio-quiet • FX-ray / Foptical > 103 • Optical excess • Blackbody fit to X-ray spectra • kTBB 85 eV, RBB 6 km
RX J2143.0+0654 line or edge? (XMM-Zane et al. 2005)