BeppoSAX observations of the three Gamma-ray pulsars PSR B0656+14, PSR B1055-52 and PSR B1706-44

Abstract

Abstract.We report the results of the observations of the three γ-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 4.5σ. 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).

Search for TeV emission from the region around PSR B1706–44 with the HESS experiment

“…The lack of observable X-ray emission below about 0.5 keV due to interstellar absorption means that the electrons producing the observed X-rays have somewhat higher energy than those producing TeV γ-rays, and an extrapolation of the X-ray spectrum to lower energies is necessary. The spectral index measured with ASCA, Γ = 1.7 +0.5 −0.4 , is fully compatible with the more precise determination from BeppoSAX, Γ = 1.69 ± 0.29 (Mineo et al 2002). The derived lower limit on the magnetic field strength is then about 1 µG when one assumes that the inverse Compton scattering involves only the photons of the microwave background radiation and assuming the same photon index in the X-ray and TeV band.…”

Thermal Structure and Cooling of Superfluid Neutron Stars with Accreted Magnetized Envelopes

“…Attributing a typical error bar (at the 90% confidence level) derived from the observations of the same source somewhat earlier (G. G. Pavlov & M. Teter 2002, private communication) we have T ∞ eff = (60 ± 6) eV. An analysis of the recent BeppoSAX observations of PSR B1055−52 gives T ∞ eff = (75 ± 6) eV (Mineo et al 2002) at the 68% confidence level. We adopt, somewhat arbitrarily, a wide T ∞ eff interval from 54 eV (the minimum value from the Chandra data) to 81 eV (the maximum value from the BeppoSAX data).…”

“…The results of different groups are not fully consistent because of the complexity of observations and their interpretation. For instance, according to G. G. Pavlov (2002, private communication), the best-fit value obtained from the recent Chandra observations of PSR B1055À52 is T (Mineo et al 2002) at the 68% confidence level. We adopt, somewhat arbitrarily, a wide T 1 eff interval from 54 eV (the minimum value from the Chandra data) to 81 eV (the maximum value from the BeppoSAX data).…”

The Distance and Radius of the Neutron Star PSR B0656+14

“…and the stellar radius PSR B0656+14 has been extensively studied at optical (Shearer et al 1997;Kurt et al 1998;Koptsevich et al 2001), ultraviolet (Pavlov, Stringfellow, & Córdova 1996;Pavlov, Welty, & Córdova 1997;Edelstein et al 2000), x-ray (Córdova et al 1989;Finley, Ögelman, & Kiziloglu 1992;Anderson et al 1993;Greiveldinger et al 1996;Mineo et al 2002;Marshall & Schulz 2002;Pavlov et al 2002), and gamma-ray (Ramanamurthy et al 1996) energies.…”