2007ApJ...660.1413K

We detected X-ray emission from PSR B1800-21 (J1803-2137) and its synchrotron nebula with the Chandra X-Ray Observatory. The observed pulsar flux is (1.4±0.2)x10^–14 ergs/cm2/s in the 1-6 keV band. The spectrum can be described by a two-component power law + blackbody (PL+BB) model, suggesting a mixture of thermal and magnetospheric emission. For a plausible n_H=1.4x10²²/cm2, the PL component has a slope Γ=1.4±0.6 and a luminosity L^nonth_PSR=4x10³¹(d/4 kpc)² ergs/s. The properties of the thermal component (kT=0.1-0.3 keV, L^bol_PSR=10³¹-10³³ ergs/s) are very poorly constrained because of the strong interstellar absorption. The compact, 7"x4", inner pulsar wind nebula (PWN), elongated perpendicular to the pulsar's proper motion, is immersed in a fainter asymmetric emission. The observed flux of the PWN is (5.5±0.6)x10^–14 ergs/cm2/s in the 1-8 keV band. The PWN spectrum fits a PL model with Γ=1.6±0.3, L_PWN=1.6x10³²(d/4 kpc)² ergs/s. The shape of the inner PWN suggests that the pulsar moves subsonically and X-ray emission emerges from a torus associated with the termination shock in the equatorial pulsar wind. The inferred PWN-pulsar properties (e.g., the PWN X-ray efficiency, L_PWN/E{dot}∼10^–4; the luminosity ratio, L_PWN/L^nonth_PSR=4; the pulsar wind pressure at the termination shock, p_s=10^–9 ergs/cm3) are very similar to those of other subsonically moving Vela-like objects detected with Chandra (L_PWN/E{dot}∼10^–4.5 to 10^–3.5, L_PWN/L^nonth_PSR∼5, p_s=10^–10 to 10^–8 ergs/cm).