Journal articles: 'Radio lines'

1

Konovalenko, A. A., and S. V. Stepkin. "Radio recombination lines." EAS Publications Series 15 (2005): 271–95. http://dx.doi.org/10.1051/eas:2005158.

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2

Christiansen, Donald. "Spectral lines: Radio days." IEEE Spectrum 24, no. 4 (1987): 27. http://dx.doi.org/10.1109/mspec.1987.6447966.

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Jackson, Neal, and I. W. A. Browne. "Quasar emission lines, radio structures and radio unification." Monthly Notices of the Royal Astronomical Society 429, no. 2 (December 22, 2012): 1781–90. http://dx.doi.org/10.1093/mnras/sts468.

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Stasińska, Grażyna, Natalia Vale Asari, and Dorota Kozieł-Wierzbowska. "Radio galaxies with and without emission lines." Proceedings of the International Astronomical Union 15, S359 (March 2020): 396–401. http://dx.doi.org/10.1017/s1743921320001866.

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AbstractUsing the recent ROGUE I catalogue of galaxies with radio cores (Kozie_l-Wierzbowska et al. 2020) and after selecting the objects which are truly radio active galactic nuclei, AGNs, (which more than doubles the samples available so far), we perform a thorough comparison of the properties of radio galaxies with and without optical emission lines (galaxies where the equivalent width of Hα is smaller than 3Å are placed in the last category). We do not find any strong dichotomy between the two classes as regards the radio luminosities or black hole masses. The same is true when using the common classification into high- and low-excitation radio galaxies (HERGs and LERGs respectively).

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Dravskikh, A. F., and Yu A. Dravskikh. "Recombination Radio Lines of the Sun." Astronomy Reports 66, no. 6 (June 2022): 490–99. http://dx.doi.org/10.1134/s1063772922060038.

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Peters, W. M., T. J. W. Lazio, T. E. Clarke, W. C. Erickson, and N. E. Kassim. "Radio recombination lines at decametre wavelengths." Astronomy & Astrophysics 525 (December 8, 2010): A128. http://dx.doi.org/10.1051/0004-6361/201014707.

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Yevhraphov, Dmytro. "SDR- Thechnologies of Covert radio Lines." Modern Special Technics 4(59) (2019): 72–80. http://dx.doi.org/10.36486/mst2411-3816.2019.4(59).8.

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Zorpette, Glenn. "Exploring the radio spectrum [Spectral Lines]." IEEE Spectrum 51, no. 11 (November 2014): 10–12. http://dx.doi.org/10.1109/mspec.2014.6934913.

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Peach, G. "The radio recombination lines of hydrogen." Advances in Space Research 54, no. 7 (October 2014): 1180–83. http://dx.doi.org/10.1016/j.asr.2013.08.020.

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10

Calvani, M., J. W. Sulentic, P. Marziani, D. Dultzin-Hacyan, and M. Moles. "A Possible Fundamental Difference Between Radio Loud and Radio Quiet AGN." Symposium - International Astronomical Union 175 (1996): 250–51. http://dx.doi.org/10.1017/s0074180900080694.

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We report on some striking differences between radio loud and quiet emitters that we found in a comparative analysis of the high and low ionization lines for 52 low redshift AGN (31 loud; 21 quiet).The broad components of Civλ1549 and Hβ were chosen as representative of the high and low ionization lines respectively. CIVλ1549 observations were obtained with the Faint Object Spectrograph on the HST. They were retrieved from the HST data archive and matching optical spectra for the region of Hβ were obtained at several ground based observatories. Details on observations, narrow/broad component deconvolution and profile cleaning from satellite lines (especially FeII) can be found in Marziani et al. (1995). The rest frame for each quasar was determined from the radial velocity of strong narrow lines, typically [Oiii]λλ4959,5007.

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11

Dvornikov, S. V., A. V. Pshenichnikov, S. S. Manaenko, and I. N. Glukhikh. "Integral model of noise-free radio communication lines." Radio industry 28, no. 4 (November 27, 2018): 8–14. http://dx.doi.org/10.21778/2413-9599-2018-28-4-8-14.

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The development of radio equipment, which can be the basis for radio lines, that can counteract various kinds of interference, both natural and artificial, has always been given special attention. In this case, the main way to interfere with such radio links is, as a rule, the expansion of the signal base. However, this method does not take into account the nature of the destructive effects in conditions of limited frequency and energy resources of radio channels. In this connection, the studies focused on the development of functional models of noise-free radio communication lines, taking into account the density of signal energy distribution in a limited state space, are relevant. This paper considers the development of an integrated model of noise-free radio communication lines, which is characterized by the accounting of statistical parameters of the radio channel model. The approaches to the estimation of efficiency of the developed functional model of the radio lines based on the calculation of information transmission reliability are presented. Theoretical solutions were obtained by the methods of statistical radio engineering and the theory of telecommunications; they are generalized for the models of channels with variable parameters in conditions of nonrandom destructive influence. А positive effect of the practical implementation of the developed model is shown on the basis of analytical modeling.

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Kuz'min, A. D. "Observational Constraints on the Structure of the Pulsar Magnetic Field." International Astronomical Union Colloquium 128 (1992): 1–6. http://dx.doi.org/10.1017/s0002731600154629.

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The most widely adopted model of pulsar radio emission is the hollow cone model, which fits much of the experimental data. The pulsar radio emission in this model is curvature radiation of relativistic particles flowing from the magnetic poles of the neutron star along a cone of open magnetic lines. The curvature radiation is amplified at the plasma frequency, therefore different radio frequencies f originate at different radii r of the emitting regions.

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13

Sadler, Elaine M. "Low-Luminosity Active Nuclei in Elliptical Galaxies." Symposium - International Astronomical Union 121 (1987): 443–50. http://dx.doi.org/10.1017/s0074180900155469.

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The results of a sensitive radio and optical survey of nearby early-type galaxies show that most (perhaps all) bright ellipticals have ‘active’ nuclei. These are characterized by a central non-thermal radio source and a weak LINER-like optical emission spectrum. There appears to be a smooth continuity in optical and radio properties from the weakest nearby sources to strong radio galaxies. Galaxies with radio sources usually show optical emission lines, but there is no simple relationship between gas content and radio power.

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Samoylov, A. G., V. S. Samoylov, and S. A. X. Nasir. "Loss of radio waves energy on radio lines satellite-earth station." Journal of Physics: Conference Series 2094, no. 4 (November 1, 2021): 042080. http://dx.doi.org/10.1088/1742-6596/2094/4/042080.

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Abstract The main contribution of this paper is to study the influence of various natural factors on the conditions for the radio signals propagation on the satellite - Earth links. It is shown that the ionosphere practically does not interfere with satellite radio communications at frequencies above 5 GHz. The mathematical model is proposed for the numerical determination of the attenuation of the radio signal depending on the optical visibility during dust storms along the communication path.

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15

Sewilo, M., E. Churchwell, S. Kurtz, W. M. Goss, and P. Hofner. "Broad Radio Recombination Lines from Hypercompact HiiRegions." Astrophysical Journal 605, no. 1 (April 10, 2004): 285–99. http://dx.doi.org/10.1086/382268.

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Konovalenko, A. A., S. V. Stepkin, and D. V. Shalunov. "Recombination Radio Lines at Very Low Frequencies." Symposium - International Astronomical Union 199 (2002): 349–50. http://dx.doi.org/10.1017/s007418090016930x.

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17

Anantharamaiah, K. R. "3.29. Radio recombination lines from starburst galaxies." Symposium - International Astronomical Union 184 (1998): 147–48. http://dx.doi.org/10.1017/s0074180900084424.

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Starburst activity is often heavily obscured by dust. To see through the dust and measure the full extent, power and dynamics of the starburst, we are surveying hydrogen radio recombination lines (RRLs) from famous nearby starburst galaxies. Exploiting the improved sensitivity and dynamic range of aperture synthesis arrays such as the VLA and the AT and millimeter-wave telescopes such as SEST and the IRAM-30m telescope, we have searched for RRLs in about 25 starburst galaxies. RRLs have been detected in 14 galaxies. The observations were made variously at 1.4, 4.9, 8.4, 86, 135 and 232 GHz (Anantharamaiah et al 1993, Zhao et al 1996, 1997, Phookun et al 1997). Table 1 summarizes the observations. In all the cases the detected line originates in the nuclear starburst region and the emission region is resolved with a beam of 1–3″.

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Kunert-Bajraszewska, Magdalena, and Marcin P. Gawroński. "Radio Structures of Compact Quasars with Broad Absorption Lines." Proceedings of the International Astronomical Union 5, S267 (August 2009): 114. http://dx.doi.org/10.1017/s1743921310005752.

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AbstractBroad absorption lines (BALs), seen in a small fraction of both the radio-quiet and radio-loud quasar populations, are probably caused by the outflow of gas with high velocities and are part of the accretion process. The presence of BALs is due to a geometrical effect and/or it is connected with the quasar evolution. Using the final release of FIRST survey combined with a catalog of BAL QSOs from SDSS/DR3, we have constructed a new sample of compact radio-loud BAL QSOs, which constitutes the majority of radio-loud BAL QSOs. The main goal of this project is to study the origin of BALs by analysis of the BAL QSOs radio morphology, orientation, and jet evolution using the European VLBI Network (EVN) at 1.6 GHz and the Very Long Baseline Array (VLBA) at 5 and 8.4 GHz.

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19

Briggs, F. H. "21cm Absorption Lines at High Redshift from Intervening Galaxies." Symposium - International Astronomical Union 199 (2002): 83–90. http://dx.doi.org/10.1017/s0074180900168597.

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Radio absorption line observations of neutral hydrogen gas against extended radio sources offers the means to measure sizes and kinematics in intervening galaxies at all redshifts up to the maximum redshift where radio galaxies are detected. Such observations can therefore trace the evolution of galaxies at redshifts z ≳ 2 where the damped Lyman — α statistics indicate that the mass in neutral gas exceeded the mass in stars.

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20

Swarup, G., D. J. Saikia, M. Beltrametti, R. P. Sinha, and C. J. Salter. "Absorption lines and the radio structure of quasars." Symposium - International Astronomical Union 119 (1986): 195–96. http://dx.doi.org/10.1017/s0074180900152660.

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We have investigated a possible relationship between the radio structure of quasars and their absorption line systems with velocities, V, in the range 3000–18000 km s−1 and find a marginal trend for such quasars to have compact radio structures (Swarup et al. 1986).

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21

Lu, Ying, Zhibin Zhao, Jian gong Zhang, and Zheyuan Gan. "Fast Algorithm for Passive Interference of UHV Transmission Lines." MATEC Web of Conferences 232 (2018): 03023. http://dx.doi.org/10.1051/matecconf/201823203023.

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Passive interference analysis of transmission lines to radio stations is almost entirely based on the method of moments (MOM) or the rapid multipole method and multi-layer fast multipole method (FMM) developed by the method of moments. Based on the above algorithm, this paper proposes to use a diffraction model (UTD) and an optical diffraction method (PO) to model different transmission lines with different radii. The calculation results show that the difference of field strength generated by transmission lines with different radii varies with the distance of the observation point on the transmission line, and the accuracy of the UTO method is much smaller than that of the PO method. It can make good results that provides technical foundation for future modeling.

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22

Stepkin, S. V., O. O. Konovalenko, Y. V. Vasylkivskyi, and D. V. Mukha. "INTERSTELLAR MEDIUM AND DECAMETER RADIO SPECTROSCOPY." Radio physics and radio astronomy 26, no. 4 (November 24, 2021): 314–25. http://dx.doi.org/10.15407/rpra26.04.314.

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Purpose: The analytical review of the main results of research in the new direction of the low-frequency radio astronomy, the interstellar medium radio spectroscopy at decameter waves, which had led to astrophysical discovery, recording of the radio recombination lines in absorption for highly excited states of interstellar carbon atoms (more than 600). Design/methodology/approach: The UTR-2 world-largest broadband radio telescope of decameter waves optimally connected with the digital correlation spectrum analyzers has been used. Continuous modernization of antenna system and devices allowed increasing the analysis band from 100 kHzto 24 MHz and a number of channels from 32 to 8192. The radio telescope and receiving equipment with appropriate software allowed to have a long efficient integration time enough for a large line series simultaneously with high resolution, noise immunity and relative sensitivity. Findings: A new type of interstellar spectral lines has been discovered and studied, the interstellar carbon radio recombination lines in absorption for the record high excited atoms with principal quantum numbers greater than 1000. The line parameters (intensity, shape, width, radial velocity) and their relation ship with the interstellar medium physical parameters have been determined. The temperature of line forming regions is about 100 K, the electron concentration up to 0.1 cm–3 and the size of a line forming region is about 10 pc. For the first time, radio recombination lines were observed in absorption. They have significant broadening and are amplified by the dielectronic-like recombination mechanism and are also the lowest frequency lines in atomic spectroscopy. Conclusions: The detected low-frequency carbon radio recombination lines and their observations have become a new highly effective tool for the cold partially ionized interstellar plasma diagnostics. Using them allows obtaining the information which is not available with the other astrophysical methods. For almost half a century of their research, a large amount of hardware-methodical and astrophysical results have been obtained including a record number of Galaxy objects, where there levant lines have been recorded. The domestic achievements have stimulated many theoretical and experimental studies in other countries, but the scientific achievements of Ukrainian scientists prove the best prospects for further development of this very important area of astronomical science. Key words: low-frequency radio astronomy; radio telescope; interstellar medium; radio recombination lines; carbon; hydrogen; spectral analyzer

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23

Koekemoer, A. M., and G. V. Bicknell. "Shock Excitation of Emission Lines in Radio Galaxies." Symposium - International Astronomical Union 175 (1996): 473–74. http://dx.doi.org/10.1017/s0074180900081535.

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We present evidence for the viability of “auto-ionizing” shocks as the dominant ionization mechanism in extended emission-line regions (EELRs) in two radio galaxies, PKS 0349–27 and PKS 2356–61. The application of this model, rather than the nuclear photoionization hypothesis of unified schemes (Barthel 1989), is motivated by observed EELR properties: large line-of-sight velocity widths (up to δv ≃ 500 km s–1 for nearby objects and ≳ 1000kms–1 at higher z); kinematics/excitation relationships (Baum et al. 1992); the EELR/radio axis alignment (Chambers et al. 1987, McCarthy et al. 1987); and the correspondence between the brighter EELR and the shorter radio lobe (McCarthy et al. 1991), suggestive of jet/gas interactions. We show that the flux, excitation and kinematics across the gas is self-consistently accounted for in terms of shocks as a single physical mechanism, requiring fewer unknown parameters than nuclear photoionization.

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24

Karelin, Sergey Y., Vitaly B. Krasovitsky, Igor I. Magda, Valentin S. Mukhin, and Victor G. Sinitsin. "Radio Frequency Oscillations in Gyrotropic Nonlinear Transmission Lines." Plasma 2, no. 2 (June 8, 2019): 258–71. http://dx.doi.org/10.3390/plasma2020018.

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The paper considers the quasi-monochromatic radio frequency oscillations that are observable in transmission lines of doubly connected cross-sections, partially filled with a magnetized ferrite. The frequencies and amplitudes of the oscillations appearing under the impact of short carrier-free electric pulses are determined by dispersive and non-linear properties of the line’s structure. The dispersion characteristics are governed by the geometry and size of the line and the spatial arrangement in the line of the ferromagnetic material with its intrinsic dispersion. The dependences shown by the oscillation parameters in real physical experiments are reproduced and analyzed via numerical simulation within models which account separately for different physical properties of the material and the structure.

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Swarup, G., D. J. Saikia, M. Beltrametti, R. P. Sinha, and C. J. Salter. "Absorption lines and the radio structure of quasars." Monthly Notices of the Royal Astronomical Society 220, no. 1 (May 1, 1986): 1–8. http://dx.doi.org/10.1093/mnras/220.1.1.

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26

Morabito, Leah K., J. B. R. Oonk, Francisco Salgado, M. Carmen Toribio, H. J. A. Röttgering, A. G. G. M. Tielens, Rainer Beck, et al. "DISCOVERY OF CARBON RADIO RECOMBINATION LINES IN M82." Astrophysical Journal 795, no. 2 (October 28, 2014): L33. http://dx.doi.org/10.1088/2041-8205/795/2/l33.

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27

Law, C. J., D. Backer, F. Yusef-Zadeh, and R. Maddalena. "RADIO RECOMBINATION LINES TOWARD THE GALACTIC CENTER LOBE." Astrophysical Journal 695, no. 2 (April 7, 2009): 1070–81. http://dx.doi.org/10.1088/0004-637x/695/2/1070.

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28

Quireza, Cintia, Robert T. Rood, Dana S. Balser, and T. M. Bania. "Radio Recombination Lines in Galactic H ii Regions." Astrophysical Journal Supplement Series 165, no. 1 (July 2006): 338–59. http://dx.doi.org/10.1086/503901.

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29

Kanekar, Nissim. "Probing fundamental constant evolution with redshifted radio lines." Proceedings of the International Astronomical Union 5, H15 (November 2009): 323. http://dx.doi.org/10.1017/s1743921310009609.

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30

Morabito, Leah K., J. B. R. Oonk, Francisco Salgado, M. Carmen Toribio, Xander Tielens, and Huub Röttgering. "Discovery of Carbon Radio Recombination Lines in M82." Proceedings of the International Astronomical Union 10, S309 (July 2014): 141–44. http://dx.doi.org/10.1017/s174392131400948x.

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AbstractCold, diffuse HI clouds are a key component of the interstellar medium (ISM), and play an important role in the evolution of galaxies. Carbon radio recombination lines (CRRLs) trace this ISM stage, and with the enormous sensitivity of LOFAR we have already begun to map and constrain the physical properties of this gas in our own Galaxy. Using LOFAR's low band antenna, we have observed M 82 and present the first ever extragalactic detection of CRRLs. We stack 22 lines to find a 8.5-sigma detection. The line peak to continuum ratio is ∼0.003, with a FWHM of 31 km s−1. The CRRL feature is consistent with an origin in the cold, neutral medium in the direction of the nucleus of M 82.

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Wyrowski, F., P. Schilke, P. Hofner, and C. M. Walmsley. "Carbon Radio Recombination Lines in the Orion Bar." Astrophysical Journal 487, no. 2 (October 1, 1997): L171—L174. http://dx.doi.org/10.1086/310893.

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32

Araya, Esteban, Willem A. Baan, and Peter Hofner. "Studies of Extragalactic Formaldehyde and Radio Recombination Lines." Astrophysical Journal Supplement Series 154, no. 2 (October 2004): 541–52. http://dx.doi.org/10.1086/423246.

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33

Li, Ruozhou, Jing Yan, Yuming Fang, Xingye Fan, Linkun Sheng, Daye Ding, Xiaoxing Yin, and Ying Yu. "Laser-Scribed Lossy Microstrip Lines for Radio Frequency Applications." Applied Sciences 9, no. 3 (January 26, 2019): 415. http://dx.doi.org/10.3390/app9030415.

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Laser-direct writing has become an alternative method to fabricate flexible electronics, whereas the resistive nature of laser-scribed conductors may distort the radio-frequency characteristics of circuits for high-frequency applications. We demonstrate that the transmission characteristics of microstrip lines are insensitive to the resistance of laser-scripted conductors when the sheet resistance is not above 0.32 Ω/□. On the other hand, the transmission and reflection characteristics of the MS lines can be simply modified through the accommodation of the resistance of the conductors, because a laser can trigger the sintering and melting of laser produced silver nanostructures. This could provide an alternative way to fabricate radio frequency (RF) resistors and promote their applications to flexible radio-frequency devices and systems.

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34

Cohen, R. J. "Circumstellar envelopes of OH-IR sources." Symposium - International Astronomical Union 122 (1987): 229–39. http://dx.doi.org/10.1017/s0074180900156499.

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This article reviews recent radio observations of maser emission from OH, H2O and SiO molecules in the circumstellar envelopes of OH-IR sources. The different radio lines require different conditions for their excitation, and each therefore probes different regions in the circumstellar envelope. For some stars radio interferometer maps of several maser lines are now available, and a consistent picture of the envelope structure is beginning to emerge.

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35

Oleksenko, Vitalii, Roman Shtonda, Yuliya Chernish, and Irina Maltseva. "MODERN APPROACHES TO PROVIDING CYBER SECURITY IN RADIO RELAY COMMUNICATION LINES." Cybersecurity: Education, Science, Technique 1, no. 17 (2022): 57–64. http://dx.doi.org/10.28925/2663-4023.2022.17.5764.

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This article examines the impact of the AcidRain malware, which was used against Ukraine during the Russian invasion. Therefore, after the disruption of the Viasat satellite Internet service, a large share of data transmission fell on other types of communication, one of which is radio relay communication. Today, radio relay communication remains one of the priority types of communication. The main conditions that determine the development of radio relay communication and the preservation of its rather high specific weight in the market for the provision of telecommunication services can be conventionally divided into organizational, technical and technological ones. In order to ensure the development of radio relay communication and to preserve its rather high specific weight in the market for the provision of telecommunication services, it is necessary to pay attention to cyber security during the construction of radio relay communication lines. To do this, each official at the appropriate level must pay attention to these points of control to ensure reliable cyber protection in radio relay communication lines, namely, have the appropriate theoretical knowledge of administrators and users in information and communication systems, communication networks, as well as properly act in practice under time to ensure cyber security when deploying radio relay communication lines. Russia's cyberattacks before the invasion of Ukraine proved that cyberattacks today play an important and strategic role in the modern world and are being waged, regardless of whether the electorate knows about it. This threat to us was and is constant and it does not stand still, but only develops. Cyberattacks cause devastating problems to our information and communication systems, communication networks and infrastructure with paradoxical, sometimes deplorable consequences. The reliable operation of radio relay communication lines depends on ensuring cyber security. You should focus on this, and at the same time make maximum efforts. Every day, technological progress will only grow more and more, paradoxically, war is the "engine of progress", and behind the growth of technical progress will be the growth of dependence in cyberspace.

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Francis, Paul J. "Optical Differences Between Radio-Loud and Radio-Quiet QSOs." Symposium - International Astronomical Union 159 (1994): 503. http://dx.doi.org/10.1017/s0074180900176764.

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We analyse the rest-frame UV spectra of a complete sample of optically selected radio-loud and radio-quiet QSOs. Our results are: 1:Broad absorption-line QSOs (BALQSOs) are all radio quiet, but they are strongly clustered toward the top end of the radio-quiet population in radio power.2:Radio-loud QSOs have higher equivalent-width, narrower high ionisation emission-lines than radio-quiet QSOs.3:Further ReadingSee Francis, Hooper & Impey, 1993, Astronomical Journal 106, 417 and references therein for more details and discussion.

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Bicknell, G. V., M. A. Dopita, and C. P. O'DEA. "Shock Excitation of Emission Lines and the Relation to GPS Sources." Symposium - International Astronomical Union 175 (1996): 469–70. http://dx.doi.org/10.1017/s0074180900081511.

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Gigahertz Peak Spectrum (GPS) and Compact Steep Spectrum (CSS) sources have attracted a large amount of attention in recent years since they occupy a surprisingly large fraction of the extragalactic radio source population. In this paper we summarise a theory which attempts to unify the optical emission line and radio properties of these sources. In outline the theory is as follows: The bow shock preceding the radio lobe driven into the ISM by a powerful radio jet ionizes the ISM producing both optical line emission and a free-free absorbing screen. The free-free absorption can explain the relationship between size and turnover frequency (Stanghellini et al., 1995) and the prediction of the line emission is in accord with the observation for a small sample of sources for which optical data are available.

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Cohen, M. H., P. M. Ogle, H. D. Iran, and R. W. Goodrich. "Unification of Radio Galaxies." International Astronomical Union Colloquium 164 (1998): 81–82. http://dx.doi.org/10.1017/s0252921100044638.

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AbstractMany FR 2 narrow-line radio galaxies also display polarized broad lines. The broad-line region is hidden from direct view and is seen by reflection (ie scattering). In these objects the spectral classification is controlled by the aspect at which they are viewed.

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Duan, Yadan, Yuandeng Shen, Xinping Zhou, Zehao Tang, Chengrui Zhou, and Song Tan. "Homologous Accelerated Electron Beams, a Quasiperiodic Fast-propagating Wave, and a Coronal Mass Ejection Observed in One Fan-spine Jet." Astrophysical Journal Letters 926, no. 2 (February 1, 2022): L39. http://dx.doi.org/10.3847/2041-8213/ac4df2.

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Abstract Using imaging and radio multi-wavelength observations, we studied the origin of two homologous accelerated electron beams and a quasiperiodic fast-propagating (QFP) wave train associated with a solar jet on 2012 July 14. The jet occurred in a small-scale fan-spine magnetic system embedded in a large-scale pseudostreamer associated with a GOES C1.4 flare, a jet-like coronal mass ejection (CME), a type II radio burst, and a type III radio burst. During the initial stage, a QFP wave train and a fast-moving on-disk radio source were detected in succession ahead of the jet along the outer spine of the fan-spine system. When the jet reached a height of about 1.3 solar radii, it underwent a bifurcation into two branches. Based on our analysis results, all the observed phenomena in association with the jet can be explained by using a fan-spine magnetic system. We propose that both the type III radio burst and the on-disk fast-moving radio source were caused by the same physical process, i.e., energetic electrons accelerated by magnetic reconnection at the null point, and these energetic electrons were propagating along the open field lines of the pseudostreamer and the closed outer spine of the fan-spine structure, respectively. Due to the bifurcation of the jet body, the lower branch along the closed outer spine of the fan-spine structure fell back to the solar surface, while the upper branch along the open field lines of the pseudostreamer caused the jet-like CME in the outer corona.

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40

Fisher, J. Richard. "The Nature of Radio Interference and Some Lines of Defense." International Astronomical Union Colloquium 112 (1991): 240–48. http://dx.doi.org/10.1017/s0252921100004061.

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ABSTRACTAs competition for radio spectrum space continues to increase, radio astronomers can expect to put more technical effort into ways of observing in the presence of interference. Much of the spectrum outside of exclusive radio astronomy frequency bands will continue to be available to the science if receivers and antennas are designed to make efficient use of times, frequencies, directions, and coherence envelopes that do not contain sources of interference. The paper outlines the state of the art in antenna sidelobe reduction, high dynamic range spectrometers, and receiver designs for handling large signals. Techniques for excising pulsed interference on very short timescales and a few thoughts on signal canceling techniques are discussed.

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Roshi, D. Anish, N. G. Kantharia, and K. R. Anantharamaiah. "Galactic Carbon Recombination Lines near 327 MHz." Symposium - International Astronomical Union 199 (2002): 345–46. http://dx.doi.org/10.1017/s0074180900169281.

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A survey of radio recombination lines (RRLs) in the Galactic plane (l = 332° − 0° − 89°) near 327 MHz made using the Ooty Radio Telescope (ORT) has detected carbon RRLs from all the positions in the longitude range 0° < l < 20° and from a few positions at other longitudes. The carbon lines detected in the survey are, most likely, emission counterparts of the absorption lines observed at frequencies below 150 MHz. Observations towards l = 13°.9, b = 0°.0 indicate that the broader (∼ 38 km s−1) carbon line detected in the lower resolution observation consists of multiple narrow components (∼ 10 km s−1) with different central velocities. The implications of the presence of such narrow components for the modeling of line emission is discussed.

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Yusef-Zadeh, F., Mark Morris, and J. H. van Gorkom. "Unusually Wide, High-Velocity Radio Recombination Lines from G0.15–0.05 in the Radio Arc." Symposium - International Astronomical Union 136 (1989): 275–80. http://dx.doi.org/10.1017/s0074180900186620.

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The H92αrecombination line was observed at 8 GHz toward the “pistol-shaped” HII region G0.15–0.05 using the VLA2in its most compact configuration. The line profiles of individual components of this source peak at VLSR=123 km/s and have total line widths of ~90 km/s. The kinematical structure of the “pistol” is unusual in that much of the neutral and ionized gas in this region is seen predominantly at either +50 or +20 km/s. The line width and radial velocity are the largest found in the Galactic center region with the exception of Sgr A West. We also found gas at VLSR=140 km/s associated with G0.18–0.04: the sickle-shaped feature which surrounds G0.15–0.05. The kinematic properties of G0.18–0.04 and G0.15–0.05 suggest that these two features are components of a single, but complex thermal system interacting with the nonthermal filaments of the radio Arc. In this regard, the width of the broad recombination line from G0.15–0.05, and its large radial velocity, might be explained as the interaction of streaming relativistic particles in the nonthermal filaments of the Arc impacting upon ambient gas clouds lying in the Galactic plane.

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Vestergaard, M., B. J. Wilkes, and P. D. Barthel. "Are Radio-Loud Quasars Rebellious or are Radio-Quiets Just Plain Untalented?" International Astronomical Union Colloquium 159 (1997): 256–57. http://dx.doi.org/10.1017/s0252921100040239.

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AbstractWe present some of the results of a preliminary statistical study of 20 QSOs. We compare equivalent widths and widths at 40–80% of flux maximum of the Lyα, Si IVλ1400, C IV λ1549, and C III] λ1909 lines between radio-loud and radio-quiet QSO subsamples and with previously reported findings.

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Toribio, M. C., L. K. Morabito, J. B. R. Oonk, F. Salgado, A. G. G. M. Tielens, and H. J. A. Röttgering. "Radio Recombination Line studies on M82 from LOFAR HBA observations." Proceedings of the International Astronomical Union 10, S309 (July 2014): 350. http://dx.doi.org/10.1017/s1743921314010412.

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AbstractWe continue our search for extragalactic Carbon Radio Recombination Lines (CRRL) in M82 with the LOw Frequency ARray (LOFAR; van Haarlem et al.2013). The goal of our project is to determine the physical conditions of the cold neutral gas in this object, for which low frequency radio recombination lines can provide a sensitive probe.

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Kharchenko, V. N., and A. A. Lavrut. "Peculiarities of energetics calculations for satellite radio communication lines." Kosmìčna nauka ì tehnologìâ 7, no. 2-3 (March 30, 2001): 33–34. http://dx.doi.org/10.15407/knit2001.02.033.

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Roy, A. L., W. M. Goss, Niruj R. Mohan, and K. R. Anantharamaiah. "Radio recombination lines from the starburst galaxy NGC 3256." Astronomy & Astrophysics 435, no. 3 (May 13, 2005): 831–37. http://dx.doi.org/10.1051/0004-6361:20041825.

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Konovalenko, A. A., S. V. Stepkin, and E. V. Vasilkovskiy. "Low-frequency radio recombination lines: observations and data processing." Kosmìčna nauka ì tehnologìâ 23, no. 1 (January 30, 2017): 50–53. http://dx.doi.org/10.15407/knit2017.01.050.

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Jackson, N., and I. W. A. Browne. "Systematic asymmetries in H lines of radio-loud quasars." Monthly Notices of the Royal Astronomical Society 236, no. 1 (January 1, 1989): 97–105. http://dx.doi.org/10.1093/mnras/236.1.97.

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Deguchi, S., and W. D. Watson. "Circular polarization of interstellar absorption lines at radio frequencies." Astrophysical Journal 289 (February 1985): 621. http://dx.doi.org/10.1086/162925.

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Besnoff, Jordan S., and Matthew S. Reynolds. "Single-wire radio frequency transmission lines in biological tissue." Applied Physics Letters 106, no. 18 (May 4, 2015): 183705. http://dx.doi.org/10.1063/1.4919799.

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Journal articles on the topic 'Radio lines'

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