The accretion-powered (non-X-ray burst) pulsations of XTE J1814-338 are modeled to determine neutron star parameters and their uncertainties. The model is a rotating circular hot spot and includes: (1) an isotropic blackbody spectral component; (2) a
n anisotropic Comptonized spectral component; (3) relativistic time-delays and light-bending; and (4) the oblate shape of the star due to rotation. This model is the simplest possible model that is consistent with the data. The resulting best-fit parameters of the model favor stiff equations of state, as can be seen from the 3-sigma allowed regions in the mass-radius diagram. We analyzed all data combined from a 23 day period of the 2003 outburst, and separately analyzed data from 2 days of the outburst. The allowed mass-radius regions for both cases only allow equations of state (EOS) that are stiffer than EOS APR (Akmal et al. 1998), consistent with the large mass that has been inferred for the pulsar NGC 6440B (Freire et al. 2008). The stiff EOS inferred by this analysis is not compatible with the soft EOS inferred from a similar analysis of SAX J1808.
We obtain new HI and $^{13}$CO images around Supernova Remnants (SNR) Kes 69 and G21.5-0.9. By comparing HI spectra with $^{13}$CO emission spectra, we significantly revise the kinematic distance for Kes 69 to $sim$ 5.5 kpc, which was 11.2 kpc, and r
efine the kinematic distance for G21.5-0.9 to ~4.8 kpc. For Kes 69, the highest velocity of absorption is ~86 km/s and a prominent HI emission feature at ~ 112 km/s has no respective absorption. These new results suggest that Kes 69 is associated with a newly detected extended 1720 MHz OH maser at velocity of ~85 km/s that originates from within the bright southern radio shell of Kes 69. For G21.5-0.9, the highest velocity of absorption is ~67 km/s. The HI absorption spectra of the nearby bright source PMN J1832-1035 and of Kes 69 show a common absorption feature at velocity of ~69 km/s, which is not seen for G21.5-0.9. The resulting velocity of ~68 km/s gives the best distance estimate of ~4.8 kpc for G21.5-0.9 and associated young pulsar J1833-1034.
We provide a new distance estimate to the supernova remnant (SNR) Kes 73 and its associated anomalous X-ray pulsar (AXP) 1E 1841-045. 21 cm HI images and HI absorption/ emission spectra from new VLA observations, and 13CO emission spectra of Kes 73 a
nd two adjacent compact HII regions (G27.276+0.148 and G27.491+0.189) are analyzed. The HI images show prominent absorption features associated with Kes 73 and the HII regions. The absorption appears up to the tangent point velocity giving a lower distance limit to Kes 73 of 7.5 kpc, which has previously been given as the upper limit. Also, G27.276+0.148 and G27.491+0.189 are at the far kinematic distances of their radio recombination line velocities. There is prominent HI emission in the range 80--90 km/s for all three objects. The two HII regions show HI absorption at ~ 84 km/s, but there is no absorption in the Kes 73 absorption spectrum. This implies an upper distance limit of ~ 9.8 kpc to Kes 73. This corrected larger distance to Kes 73/ AXP 1E 1841-045 system leads to a refined age of the SNR of 500 to 1000 yr, and a ~ 50% larger AXP X-ray luminosity.
The supernova remnant (SNR) Kes 75/PSR J1846-0258 association can be regarded as certain due to the accurate location of young PSR J1846-0258 at the center of Kes 75 and the detected bright radio/X-ray synchrotron nebula surrounding the pulsar. We pr
ovide a new distance estimate to the SNR/pulsar system by analyzing the HI and $^{13}$CO maps, the HI emission and absorption spectra, and the $^{13}$CO emission spectrum of Kes 75. No absorption features at negative velocities strongly argue against the widely-used large distance of 19 to 21 kpc for Kes 75, and show that Kes 75 is within the Solar circle, i.e. a distance $d<$13.2 kpc. Kes 75 is likely at distance of 5.1 to 7.5 kpc because the highest HI absorption velocity is at 95 km/s and no absorption is associated with a nearby HI emission peak at 102 km/s in the direction of Kes 75. This distance to Kes 75 gives a reasonable luminosity of PSR J1846-0258 and its PWN, and also leads to a much smaller radius for Kes 75. So the age of the SNR is consistent with the spin-down age of PSR J1846-0258, confirming this pulsar as the second-youngest in the Galaxy.
New HI images from the VLA Galactic Plane Survey show prominent absorption features associated with the supernovae remnant G23.3-0.3 (SNR W41). We highlight the HI absorption spectra and the $^{13}$CO emission spectra of eight small regions on the fa
ce of W41, including four HII regions, three non-thermal emission regions and one unclassified region. The maximum velocity of absorption for W41 is 78$pm$2 km/s and the CO cloud at radial velocity 95$pm$5 km/s is behind W41. Because an extended TeV source, a diffuse X-ray enhancement and a large molecular cloud at radial velocity 77$pm$5 km/s are also projected at the center of W41, these yield the kinematic distance of 3.9 to 4.5 kpc for W41. For HII regions, our analyses reveal that both G23.42-0.21 and G23.07+0.25 are at the far kinematic distances ($sim$9.9 kpc and $sim$ 10.6 kpc respectively) of their recombination-line velocities (103$pm$0.5 km/s and 89.6$pm$2.1 km/s respectively), G23.07-0.37 is at the near kinematic distance (4.4$pm$0.3 kpc) of its recombination-line velocity (82.7$pm$2.0 km/s), and G23.27-0.27 is probably at the near kinematic distance (4.1$pm$0.3 kpc) of its recombination-line velocity (76.1$pm$0.6 km/s).
