2012ApJ...749..146P

We present 35 ks Chandra ACIS observations of the 42 Myr old radio pulsar PSR B1451-68. A point source is detected 0".32±0".73 from the expected radio pulsar position. It has ∼200 counts in the 0.3-8 keV energy range. We identify this point source as the X-ray counterpart of the radio pulsar. PSR B1451-68 is located close to a Two Micron All Sky Survey point source for which we derive 7% as the upper limit on the flux contribution to the measured pulsar X-ray flux. The pulsar spectrum can be described by either a power-law model with photon index Γ = 2.4^+0.4_- 0.3_ and a unrealistically high absorbing column density N_H= (2.5^+1.2_- 1.3_)x10²¹/cm2, or by a combination of a kT = 0.35^+0.12_- 0.07_ keV blackbody and a Γ = 1.4±0.5 power-law component for N ^DM_H= 2.6x10²⁰/cm2, estimated from the pulsar dispersion measure. At the parallactic, a Lutz-Kelker bias corrected distance of 480 pc, the non-thermal X-ray luminosities in the 0.3-8 keV energy band are either L ^nonth_0.3-8 keV_= (11.3±1.7)x10²⁹ erg/s or L ^nonth_0.3-8 keV_= (5.9^+4.9_- 5.0_)x10²⁹ erg/s, respectively. This corresponds to non-thermal X-ray efficiencies of either n_0.3–8keV^nonth = L_0.3-8 keV_^nonth/ {dot}E ∼ 5x10^–3 or 3x10^–3, respectively.