نتایج جستجو برای: سیستم vlbi
تعداد نتایج: 76219 فیلتر نتایج به سال:
یکى از مسائل مهم در علم مهندسى نقشه بردارى و یا امور نظامى همواره تعیین نمودن مختصات نقاط در روى زمین است که از روى آن فواصل و زوایا و دیگر پارامترهاى مورد نظر هر نقطه تا هدف و یا دیگر نقاط قابل استحصال مى باشد که براى آن خصوصا فواصل نزدیک راه حل هاى زیادى از قبیل فتوگرامترى و یا نقشه بردارى زمینى و غیره وجود دارد. ولى براى فواصل بسیار بلند مثلاً چند هزار کیلومترى بین قارهاى بدلیل برقرار نب...
For a comprehensive guide to the various array characteristics, corresponding correlator capabilities, range of diverse observing modes, different proposal submission procedures, user support etc., I refer the reader to the on-line web pages highlighted above. In this paper I have chosen to focus on a sub-set of these facilities, in particular the European VLBI Network (EVN) both in stand-alone...
We present here detailed results of an 18 cm VLBI survey of 31 luminous (LFIR > 101 1“25LO), radio-compact (0 ~O!’25) infrared galaxies (LFIRGs). High-resolution VLA maps at 15 and 22GHz are presented for 14 of these galaxies which exhibit compact milliarcsecond scale emission, providing information about radio structure of LFIRGs on scales from O !’004 to 1 !’0. We also present new optical spe...
The same beam VLBI method (SBV) is newly applied to the multi-frequency VLBI method in the VRAD mission of SELENE (KAGUYA). By simultaneously observing two nearby spacecraft with one antenna, the error sources of VLBI measurement common in two propagation paths can be almost canceled out. In this paper, error estimation and simulation analysis are carried out for a feasibility study to apply th...
We report on phase-referenced 23 GHz Very-Long-Baseline-Interferometry (VLBI) observations of the type IIb supernova SN 2008ax, made with the Very Long Baseline Array (VLBA) on 2 April 2008 (33 days after explosion). These observations resulted in a marginal detection of the supernova. The total flux density recovered from our VLBI image is 0.8±0.3 mJy (one standard deviation). As it appears, t...
Context. Short time-scale flux density variations of flat spectrum radio sources are often explained by the scattering of radio waves in the turbulent ionized Interstellar Matter of the Milky Way. One of the most convincing observational arguments in favor of this is the annual modulation of the variability time-scale caused by the Earth orbital motion around the Sun. J1128+5925 is a recently d...
As a preparation for future possible orbit determination of GNSS satellites by VLBI observations an initial three-station experiment was planned and performed in January 2009. The goal was to get first experience and to verify the feasibility of using the method for accurate satellite tracking. GNSS orbits related to a satellite constellation can be expressed in the Terrestrial Reference Frame....
This work devotes to investigations of solar corona and solar wind plasma by the method of radio probing with using of very long baseline interferometry (VLBI). We performed the theoretical calculation of power spectrum of interferometric response to radio source emission, passed through the turbulent medium. Data of theoretical analysis are compared with results of international VLBI experimen...
We report on 1.6 GHz Very-Long-Baseline-Interferometry (VLBI) observations of supernova SN 1979C made on 18 November 2002. We derive a model-dependent supernova size. We also present a reanalysis of VLBI observations made by us on June 1999 and by other authors on February 2005. We conclude that, contrary to our earlier claim of strong deceleration in the expansion, SN 1979C has been undergoing...
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