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Register a new userSome arguments in support of the association of PSR B1706-44 with the supernova remnant G343.1-2.3
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We present some arguments in support of the association of the pulsar PSR B1706-44 with the supernova remnant G343.1-2.3, based on the idea that these objects could be the result of a supernova explosion within a mushroom-like cavity (created by the supernova progenitor wind breaking out of the parent molecular cloud). We suggest that in addition to the known bright half of G343.1-2.3 there should exist a more extended and weaker component, such that the actual shape of G343.1-2.3 is similar to that of the well-known SNR VRO 42.05.01. We have found such a component in archival radio data.
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We report on the XMM-Newton observations of the young, 102 ms pulsar PSR B1706-44. We have found that both a blackbody plus power-law and a magnetized atmospheric model plus power-law provide an excellent fit to the EPIC spectra. The two scenarios are therefore indistinguishable on a statistical basis, although we are inclined to prefer the latter on physical grounds. In this case, assuming a source distance of ~2.3 kpc, the size of the region responsible for the thermal emission is R~13 km, compatible with the surface of a neutron star. A comparison of the surface temperature of PSR B1706-44 obtained from this fit with cooling curves favor a medium mass neutron star with M~1.45 solar masses or M~1.59 solar masses, depending on two different models of proton superfluidity in the interior. The large collecting area of XMM-Newton allows us to resolve a substructure in the broad soft X-ray modulation detected by Chandra, revealing the presence of two separate peaks with pulsed fractions of 7 +/- 4% and 15 +/- 3%, respectively.
We report the results of the observations of the three gamma-ray pulsars PSR B0656+14, PSR B1055-52 and PSR B1706-44 performed with BeppoSAX. We detected a pulsed emission only for PSR B1055-52: in the range 0.1-6.5 keV the pulse profile is sinusoidal and the statistical significance is 4.5 sigma. The pulsed fraction was estimated 0.64+/-0.17. This pulsation was detected also at energies greater than 2.5 keV suggesting either a non-thermal origin or a quite high temperature region on the neutron star surface. Spectral analysis showed that only the X-ray spectrum of PSR B1706-44 can be fitted by a single power-law component, while that of PSR B1055-52 requires also a blackbody component (kT = 0.075 keV) and that of PSR B0656+14 two blackbody components (kT_1 = 0.059, kT_2 = 0.12 keV).
The energetic pulsar PSR B1706-44 and the adjacent supernova remnant (SNR) candidate G 343.1-2.3 were observed by H.E.S.S. during a dedicated observational campaign in 2007. A new source of very-high-energy (VHE; E > 100 GeV) gamma-ray emission, HESS J1708-443, was discovered with its centroid at RA(J2000) = 17h08m10s and Dec(J2000) = -44d21, with a statistical error of 3 arcmin on each axis. The VHE gamma-ray source is significantly more extended than the H.E.S.S. point-spread function, with an intrinsic Gaussian width of 0.29 +/- 0.04 deg. Its energy spectrum can be described by a power law with a photon index Gamma = 2.0 +/- 0.1 (stat) +/- 0.2 (sys). The integral flux measured between 1-10 TeV is ~17% of the Crab Nebula flux in the same energy range. The possible associations with PSR B1706-44 and SNR G343.1-2.3 are discussed.
We have obtained a deep 670 ks CXO ACIS image of the remarkable pulsar wind nebula (PWN) of PSR J1709-4429, in 4 epochs during 2018-2019. Comparison with an archival 2004 data set provides a pulsar proper motion mu = 13 pm 3 mas/yr at a PA of 86 pm 9 degree (1 sigma combined statistical and systematic uncertainties), precluding birth near the center of SNR G343.1-2.3. At the pulsars characteristic age of 17 kyr, the association can be preserved through a combination of progenitor wind, birth kick and PWN outflow. Associated TeV emission may, however, indicate explosion in an earlier supernova. Inter-epoch comparison of the X-ray images shows that the PWN is dynamic, but we are unable to conclusively measure flow speeds from blob motion. The pulsar has generated a radio/X-ray wind bubble, and we argue that the PWNs long narrow jets are swept back by shocked pulsar wind venting from this cavity. These jets may trace the polar magnetic field lines of the PWN flow, an interesting challenge for numerical modeling.
We have used the NRAO Very Large Array (VLA) in conjunction with the Very Long Baseline Array (VLBA) Pie Town antenna as a real-time interferometer system to measure the size of the extragalactic source J1801-231 as a function of frequency from 1285 to 4885 MHz. These observations were made in an attempt to determine the effect interstellar scattering has on the observed sizes of OH (1720 MHz) masers in the nearby (d=2.5 kpc) supernova remnant W28. The observations clearly show that J1801-231 displays angular broadening due to turbulence in the Galaxys interstellar medium. The minimum distance of the nearby (two arcminutes from J1801-231) pulsar PSR B1758-23 is constrained to be 9.4 +/- 2.4 kpc. This value is based on both the measured size of 220 mas for J1801-231 at 1715 MHz and the temporal broadening of the pulsar. A single thin scattering screen along the line of sight to the W28 OH(1720 MHz) masers must be at 4.7 +/- 1.2 kpc for this minimum pulsar distance. The screen may be placed closer to the Earth, but for reasonable values of the pulsar distance (i.e., the pulsar is within the Galaxy), this choice leads to a negligible scattering contribution to the sizes of the masers. Thus the OH(1720 MHz) masers, at a distance of 2.5 +/- 0.7 kpc, are unaffected by interstellar scattering, and the measured maser sizes must be intrinsic. Our measured upper limits to the size of the pulsar itself are consistent with the distance estimates to the pulsar and the scattering screen.
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