共查询到20条相似文献,搜索用时 31 毫秒
1.
Using the published data of multi-frequency time-aligned pulse profiles from Kuzmin et al. (1998), we calculate the phase-resolved spectra of PSRs B0525+21 and B2020+28. The results reveal that conal-double pulsars have common ‘M’-shaped phase-resolved spectra. 相似文献
2.
We monitored PSR B0329+54 for one year using the Nanshan 25-m radio telescope, the scintillation velocity V ISS shows evidence of systematic variation with the day of the year. States of interstellar medium (ISM) are discussed. 相似文献
3.
Esamudin Ali Wu Xin-ji Zhang Jin Wang Na Kang Lian-sheng Jin Sheng-zheng Zhang Hong-bo Wang Wei-xia 《Chinese Astronomy and Astrophysics》2000,24(4):467-472
We present the results of observations of the pulsar PSR B0329+54 at 0.327, 1.5, 2.3, 4.8 and 8.4 GHz during 1999 between 03–12 and 06–08, using the 25-m radio telescope of NAOC Urumqi Station. The spectrum shows a bend, the spectral index is 1.59 at the low frequency end, and 2.45 at the high frequency end. The angular width of the average pulse profile and the angular separation between two weak peaks both decrease with increasing frequency. 相似文献
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Previous studies have identified two emission modes in PSR B1859+07: a normal mode that has three prominent components in the average profile, with the trailing one being the brightest, and an anomalous mode(i.e., the A mode) where emissions seem to be shifted to an earlier phase. Within the normal mode, further analysis has revealed the presence of two submodes, i.e., the cW mode and c B mode, where the central component can appear either weak or bright. As for the anomalous mode, a new bright ... 相似文献
6.
Jun Tan Zhi-Gang Wen Zhen Wang Xue-Feng Duan Hong-Guang Wang Na Wang Vishal Gajjar Jian-Ping Yuan Rai Yuen Wen-Ming Yan Jian-Ling Chen Wei Han Hui Wang Cheng-Bing Lyu Ai-Jun Dong 《天文和天体物理学研究(英文版)》2024,(4):255-263
We have conducted a comprehensive investigation into the bright single pulse emission from PSR B1133+16using the Giant Metrewave Radio Telescope. High time resolution data (61μs) were obtained at a center frequency of 322 MHz with a bandwidth of 32 MHz over a continuous observation period of 7.45 hr. A total of 1082 bright pulses were sporadically detected with peak flux densities ranging from 10 to 23 times stronger than the average pulse profile. However, no giant pulse-like emission with a re... 相似文献
7.
S. Zharikov R. E. Mennickent Yu. Shibanov V. Komarova 《Astrophysics and Space Science》2007,308(1-4):545-549
We have obtained the spectrum of a middle-aged PSR B0656+14 in the 4300–9000 Å range with the ESO/VLT/FORS2. Preliminary results show that at 4600–7000 Å the spectrum is almost featureless and flat with a spectral index α ν ??0.2 that undergoes a change to a positive value at longer wavelengths. Combining with available multiwavelength data suggests two wide, red and blue, flux depressions whose frequency ratio is about 2 and which could be the 1st and 2nd harmonics of electron/positron cyclotron absorption formed at magnetic fields ~108 G in upper magnetosphere of the pulsar. 相似文献
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Observations obtained in the last years challenged the widespread notion that rotation-powered neutron stars are steady X-ray emitters. Besides a few allegedly rotation-powered neutron stars that showed ‘magnetar-like’ variability, a particularly interesting case is that of PSR B0943+10. Recent observations have shown that this pulsar, well studied in the radio band where it alternates between a bright and a quiescent mode, displays significant X-ray variations, anticorrelated in flux with the radio emission. The study of such synchronous radio/X-ray mode switching opens a new window to investigate the processes responsible for the pulsar radio and high-energy emission. Here we review the main X-ray properties of PSR B0943+10 derived from recent coordinated X-ray and radio observations. 相似文献
10.
We have detected giant pulses from the millisecond pulsar PSR B1937+214 at the lowest frequency of 112 MHz. The observed flux density at the pulse peak is ~40 000 Jy, which exceeds the average level by a factor of 600. Pulses of such intensity occur about once per 300 000 periods. The brightness temperature of the observed giant pulses is T B≈1035 K. We estimated the pulse broadening by interstellar scattering to be τsc=3–10 ms. Based on this estimate and on published high-frequency measurements of this parameter, we determined the frequency dependence of the pulse broadening by scattering: τsc(f)=25 × (f/100)?4.0±02. 相似文献
11.
S. Stanimirović J.M. Weisberg J.M. Dickey A. de la Fuente K. Devine A. Hedden S.B. Anderson 《Astrophysics and Space Science》2004,292(1-4):167-172
In this paper we present and discuss the great difference in OH absorption spectra against PSR B1849+00 and SNR G33.6+0.1 along the same line-of-sight. This finding is important as it clearly demonstrates that statistics of absorbing molecular gas depends on the size of the background source. 相似文献
12.
A. K. Mitra 《Astrophysics and Space Science》1990,174(1):135-141
We intend to point out that existing evolutionary scenario for the genesis of the binary radio pulsars like PSR 0655+64 (P1 d) and 1913+16 (P8 hr) having short orbital periods and relatively massive companion (>0.5M
*) is inconsistent in that it does not allow for a prolonged phase of angular momentum transfer. We propose here a modified evolutionary scenario where there is such a prolonged phase of angular momentum transfer from a low mass helium star to the neutron star mediated by an accretion disk along the so-called caseB evolutionary track. 相似文献
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We detected giant pulses from the pulsar PSR B1112+50. A pulse with an intensity that is a factor of 30 or more higher than the intensity of the average pulse is encountered approximately once in 150 observed pulses. The peak flux density of the strongest pulse is about 180 Jy. This value is a factor of 80 higher than the peak flux density of the average pulse. The giant pulses are narrower than the average profile by approximately a factor of 5 and they cluster about the center of the average profile. 相似文献
14.
M. T. Reynolds P. J. Callanan A. S. Fruchter M. A. P. Torres M. E. Beer R. A. Gibbons 《Monthly notices of the Royal Astronomical Society》2007,379(3):1117-1122
We present a new analysis of the light curve for the secondary star in the eclipsing binary millisecond pulsar system PSR B1957+20. Combining previous data and new data points at minimum from the Hubble Space Telescope , we have 100 per cent coverage in the R -band. We also have a number of new K s -band data points, which we use to constrain the infrared magnitude of the system. We model this with the eclipsing light-curve (ELC) code. From the modelling with the ELC code we obtain colour information about the secondary at minimum light in BVRI and K . For our best-fitting model we are able to constrain the system inclination to 65°± 2° for pulsar masses ranging from 1.3 to 1.9 M⊙ . The pulsar mass is unconstrained. We also find that the secondary star is not filling its Roche lobe. The temperature of the unirradiated side of the companion is in agreement with previous estimates and we find that the observed temperature gradient across the secondary star is physically sustainable. 相似文献
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Giant pulses (GPs) have been detected from the pulsar PSR B0656 + 14. A pulse that is more intense than the average pulse by a factor of 120 is encountered approximately once in 3000 observed periods of the pulsar. The peak flux density of the strongest pulse, 120 Jy, is a factor of 630 higher than that of the average pulse. The GP energy exceeds the energy of the average pulse by up to a factor of 110, which is comparable to that for other known pulsars with GPs, including the Crab pulsar and the millisecond pulsar PSR B1937+21. The giant pulses are a factor of ~6 narrower than the average pulse and are clustered at the head of the average pulse. PSR B0656+14 along with PSR B0031-07, PSR B1112+50, and PSR J1752+2359 belong to a distinctive group of pulsars in which GPs have been detected without any extremely strong magnetic field on the light cylinder. 相似文献
17.
Katherine E. McGowan W. Thomas Vestrand Jamie A. Kennea Silvia Zane Mark Cropper France A. Córdova 《Astrophysics and Space Science》2007,308(1-4):309-316
We present X-ray data of the middle-aged radio pulsar PSR B0355+54. The XMM-Newton and Chandra observations show not only
emission from the pulsar itself, but also compact diffuse emission extending ∼50″ in the opposite direction to the pulsar’s
proper motion. Our analysis also indicates the presence of fainter diffuse emission extending ∼5′ from the point source. The
morphology of the diffuse component is similar to the ram-pressure confined pulsar wind nebulae detected for other sources.
We find that the compact diffuse component is well-fitted with a power-law, with an index that is consistent with the values
found for other pulsar wind nebulae. The core emission from the pulsar can be characterized with a thermal plus power-law
fit, with the thermal emission most likely originating in a hot polar cap. 相似文献
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Using the multifrequency radio profiles of pulsar PSR B2319+60, two parameters of inverse Compton scattering model, the initial Lorentz factor and the factor of energy loss of relativistic particles are constrained. 相似文献
20.
Constraining the relative inclinations of the planets B and C of the millisecond pulsar PSR B1257+12
Lorenzo Iorio 《Journal of Astrophysics and Astronomy》2010,31(3):147-153
We investigate on the relative inclination of the planets B and C orbiting the pulsar PSR B1257+12. First, we show that the
third Kepler’s law does represent an adequate model for the orbital periods P of the planets, because other Newtonian and Einsteinian corrections are orders of magnitude smaller than the accuracy in
measuring P
B/C. Then, on the basis of available timing data, we determine the ratio sin i
C/ sin i
B = 0.92±0.05 of the orbital inclinations i
B and i
C independently of the pulsar’s mass M. It turns out that coplanarity of the orbits of B and C would imply a violation of the equivalence principle. Adopting a
pulsar mass range 1 ≲ M ≲ 3, in solar masses (supported by present-day theoretical and observational bounds for pulsar’s masses), both face-on and
edge-on orbital configurations for the orbits of the two planets are ruled out; the acceptable inclinations for B span the
range 36 deg ≲ i
B ≲ 66 deg, with a corresponding relative inclination range 6 deg ≲ (i
C − i
B) ≲ 13 deg. 相似文献