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1.
We explore the possibility of searching for groups of radio sources from the FIRST catalog on angular scales 1′–5′. We developed an efficient method of searching for such groups that takes into account the need for combining the components of extended sources represented in the catalog by separate objects. We found 31 groups of radio sources with angular sizes <5′ that contain no fewer than five sources with flux densities ≥3 mJy. This number is at least triple the expected number of such groups for a random Poisson distribution of radio sources in the sky. The prospects for using groups of radio sources to detect and study distant systems of galaxies are discussed. 相似文献
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Yu. P. Ilyasov M. Imae Y. Hanado V. V. Oreshko V. A. Potapov A. E. Rodin M. Sekido 《Astronomy Letters》2005,31(1):30-36
We present the results from our timing of the millisecond pulsar B1937+21, performed jointly since 1997 on two radio telescopes: the RT-64 in Kalyazin (Russia) at a frequency of 0.6GHz and RT-34 in Kashima (Japan) at a frequency of 2.15 GHz. The rms value of the pulse time of arrival (TOA) residuals for the pulsar at the barycenter of the Solar system is 1.8 μs (the relative variation is ≈10?14 over the observing period). The TOA residuals are shown to be dominated by white phase noise, which allows this pulsar to be used as an independent time scale keeper. The upper limit for the gravitational background energy density Ωgh2 at frequencies ≈6.5 × 10?9 Hz is estimated to be no higher than 10?6. Based on the long-term timing of the pulsar, we have improved its parameters and accurately determined the dispersion measure and its time variation over the period 1984–2002, which was, on average, ?0.00114(3) pc cm?3 yr?1. 相似文献
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Astronomy Reports - The results of observations of the pulsar B0301+19 (J0304+1932) carried out on the Large Scanning Antenna of the Pushchino Radio Astronomy Observatory at 111 MHz during... 相似文献
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An analysis of data from monitoring of individual pulses of the second-period pulsar PSR B1237+25 (J1239+2453) carried out on the Large Phased Array (LPA) of the Pushchino Radio Astronomy Observatory at 111 MHz during 2012–2015 is presented. The aim of this observing program is a search for anomalously strong and giant pulses. The regular generation of powerful individual pulses at the longitudes of three of five components in the main profile of PSR B1237+25 has been detected. The distribution of these strong pulses in flux density is bimodal, and has the power-law form characteristic for giant pulses, with power-law indices n = ?1.26 ± 0.05 and ?3.36 ± 0.34, which differentiates them from the regular pulses of pulsars, having a log–normal distribution. The characteristic pulse widths at the half-intensity level are 3–5 ms, which comprises 50–100% of the width of the corresponding component in the mean profile. The most powerful of the detected pulses had a peak flux density of 900 ± 160 Jy, and the strongest pulse exceeded the session-mean profile by a factor of 65. 相似文献
6.
V. I. Degtyarev I. P. Kharchenko A. S. Potapov B. Tsegmed S. E. Chudnenko 《Geomagnetism and Aeronomy》2010,50(7):885-893
The dynamics of the Pc5 and Pi1 pulsation characteristics and relativistic electron fluxes at geostationary orbit were comparatively
analyzed for three nine-day intervals, including quiet periods and periods of geomagnetic storms. It was shown that relativistic
electron fluxes increase considerably when the power of global Pc5 pulsations and the index of midlatitude irregular Pi1 pulsations
increase simultaneously. The correlation between the characteristics of Pi1 and Pc5 geomagnetic pulsations and the level of
the relativistic electron flux at geostationary orbit during the magnetic storm recovery phase were studied. It was shown
that the correlation coefficient of the relativistic electron maximal fluxes during the magnetic storm recovery phase with
the parameter of midlatitude Pi1 pulsations is slightly higher than such a correlation coefficient with the solar wind velocity. 相似文献
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According to BGO data, it is discovered that ionospheric Alfvén resonances (IARs) observed as geomagnetic pulsations at frequencies of a few hertz arise in response to seismic events. The paper presents examples showing how seismic waves affect the IAR regime. Possible mechanisms of this effect are discussed. 相似文献
10.
The finest open fractures (ultramicrofractures) were found from the study of surface density of open fractures in the rocks
from the super-deep Uralian borehole SG-4. The high-resolution method of the registration of open fractures in the rocks is
described. The typical structures of systems formed by open fractures are shown and their genesis is proposed. 相似文献