WorldWideScience

Sample records for counterparts iii radio

  1. X-ray Counterparts of Infrared Faint Radio Sources

    Science.gov (United States)

    Schartel, Norbert

    2011-10-01

    Infrared Faint Radio Sources (IFRS) are radio sources with extremely faint or even absent infrared emission in deep Spitzer Surveys. Models of their spectral energy distributions, the ratios of radio to infrared flux densities and their steep radio spectra strongly suggest that IFRS are AGN at high redshifts (2IFRS, but if confirmed, the increased AGN numbers at these redshifts will account for the unresolved part of the X-ray background. The identification of X-ray counterparts of IFRS is considered to be the smoking gun for this hypothesis. We propose to observe 8 IFRS using 30ks pointed observations. X-ray detections of IFRS with different ratios of radio-to-infrared fluxes, will constrain the class-specific SED.

  2. A radio counterpart to a neutron star merger.

    Science.gov (United States)

    Hallinan, G; Corsi, A; Mooley, K P; Hotokezaka, K; Nakar, E; Kasliwal, M M; Kaplan, D L; Frail, D A; Myers, S T; Murphy, T; De, K; Dobie, D; Allison, J R; Bannister, K W; Bhalerao, V; Chandra, P; Clarke, T E; Giacintucci, S; Ho, A Y Q; Horesh, A; Kassim, N E; Kulkarni, S R; Lenc, E; Lockman, F J; Lynch, C; Nichols, D; Nissanke, S; Palliyaguru, N; Peters, W M; Piran, T; Rana, J; Sadler, E M; Singer, L P

    2017-10-16

    Gravitational waves have been detected from a binary neutron star merger event, GW170817. The detection of electromagnetic radiation from the same source has shown that the merger occurred in the outskirts of the galaxy NGC 4993, at a distance of 40 megaparsecs from Earth. We report the detection of a counterpart radio source that appears 16 days after the event, allowing us to diagnose the energetics and environment of the merger. The observed radio emission can be explained by either a collimated ultra-relativistic jet viewed off-axis, or a cocoon of mildly relativistic ejecta. Within 100 days of the merger, the radio light curves will distinguish between these models and very long baseline interferometry will have the capability to directly measure the angular velocity and geometry of the debris. Copyright © 2017, American Association for the Advancement of Science.

  3. INTERSTELLAR SCINTILLATION AND THE RADIO COUNTERPART OF THE FAST RADIO BURST FRB 150418

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    Akiyama, Kazunori [Massachusetts Institute of Technology, Haystack Observatory, Route 40, Westford, MA 01886 (United States); Johnson, Michael D., E-mail: kazu@haystack.mit.edu [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2016-06-10

    Keane et al. have recently reported the discovery of a new fast radio burst (FRB), FRB 150418, with a promising radio counterpart at 5.5 and 7.5 GHz—a rapidly decaying source, falling from 200–300 μ Jy to 100 μ Jy on timescales of ∼6 days. This transient source may be associated with an elliptical galaxy at redshift z = 0.492, providing the first firm spectroscopic redshift for an FRB and the ability to estimate the density of baryons in the intergalactic medium via the combination of known redshift and radio dispersion of the FRB. An alternative explanation, first suggested by Williams and Berger, is that the identified counterpart may instead be a compact active galactic nucleus (AGN). The putative counterpart’s variation may then instead be extrinsic, caused by refractive scintillation in the ionized interstellar medium of the Milky Way, which would invalidate the association with FRB 150418. We examine this latter explanation in detail and show that the reported observations are consistent with scintillating radio emission from the core of a radio-loud AGN having a brightness temperature T {sub b} ≳ 10{sup 9} K. Using numerical simulations of the expected scattering for the line of sight to FRB 150418, we provide example images and light curves of such an AGN at 5.5 and 7.5 GHz. These results can be compared with continued radio monitoring to conclusively determine the importance of scintillation for the observed radio variability, and they show that scintillation is a critical consideration for continued searches for FRB counterparts at radio wavelengths.

  4. Radio Counterparts of Compact Binary Mergers Detectable in Gravitational Waves: A Simulation for an Optimized Survey

    Science.gov (United States)

    Hotokezaka, K.; Nissanke, S.; Hallinan, G.; Lazio, T. J. W.; Nakar, E.; Piran, T.

    2016-11-01

    Mergers of binary neutron stars and black hole-neutron star binaries produce gravitational-wave (GW) emission and outflows with significant kinetic energies. These outflows result in radio emissions through synchrotron radiation. We explore the detectability of these synchrotron-generated radio signals by follow-up observations of GW merger events lacking a detection of electromagnetic counterparts in other wavelengths. We model radio light curves arising from (I) sub-relativistic merger ejecta and (II) ultra-relativistic jets. The former produce radio remnants on timescales of a few years and the latter produce γ-ray bursts in the direction of the jet and orphan-radio afterglows extending over wider angles on timescales of weeks. Based on the derived light curves, we suggest an optimized survey at 1.4 GHz with five epochs separated by a logarithmic time interval. We estimate the detectability of the radio counterparts of simulated GW-merger events to be detected by advanced LIGO and Virgo by current and future radio facilities. The detectable distances for these GW merger events could be as high as 1 Gpc. Around 20%-60% of the long-lasting radio remnants will be detectable in the case of the moderate kinetic energy of 3\\cdot {10}50 erg and a circum-merger density of 0.1 {{cm}}-3 or larger, while 5%-20% of the orphan-radio afterglows with kinetic energy of 1048 erg will be detectable. The detection likelihood increases if one focuses on the well-localizable GW events. We discuss the background noise due to radio fluxes of host galaxies and false positives arising from extragalactic radio transients and variable active galactic nuclei, and we show that the quiet radio transient sky is of great advantage when searching for the radio counterparts.

  5. Probing the Radio Counterpart of Gamma-ray Flaring Region in 3C 84

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    Nagai Hiroshi

    2013-12-01

    Full Text Available The radio source 3C 84 associated with the radio/giant elliptical galaxy NGC 1275 is one of the best targets to probe the radio counterpart of the γ-ray emitting region. Although this source shows clear time variability in γ-ray bands, no clear correlation in radio light curve was found on the timescale of –ray variability. The location of the γ-ray flaring region has been an open question. In this proceeding, we firstly review our previous findings from radio observations. Next we present our new results based on the Very Long Baseline Array (VLBA data at 43 GHz. We discover the limb-brightened structure in the “restarted” jet associated with the 2005 radio outburst. In 1990s, the jet structure was rather ridge-brightening than limbbrightening, despite the observations were done with similar angular resolution. This indicates that the radio jet morphology in terms of the transverse structure has been indeed changed recently. This change in the morphology shows an interesting agreement with the time variation of the γ-ray flux density, i.e., the γ-ray flux density in 1990s was more than 7 times lower than the current one. We argue the possibility that the transition from ridge-brightening to limb-brightening is related to the γ-ray time variability.

  6. Optical counterpart positions of extragalactic radio sources and connecting optical and radio reference frames

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    Aslan, Z.; Gumerov, R.; Jin, W.; Khamitov, I.; Maigurova, N.; Pinigin, G.; Tang, Z.; Wang, S.

    2010-01-01

    We discuss the results of an investigation of astrometric positions of extragalactic radio sources from a list for the International Celestial Reference Frame. About 300 fields around extragalactic radio sources were observed during the years 2000-2003. The observations were performed mainly using two telescopes equipped with CCD cameras at TUG, Turkey (Russian-Turkish Telescope - RTT150) and at YAO (1 m telescope), (Kunming, China). The mean accuracies of the measured positions are 38 mas in right ascension and 35 mas in declination. A comparison between the measured optical positions determined using the UCAC2 catalog and the radio positions from the current ICRF shows that the overall optical-minus- radio offsets are -4 and +15 mas for right ascension and declination, respectively. The formal internal errors of these mean offsets are 4 mas. The results of optical positions with respect to the reference catalogue 2MASS are also given. A search for a relation between optical and radio reference frames indicates that the orientation angles are near zero within their accuracy of about 5 mas. The link accuracy becomes 3 mas when our observations are combined with other studies. Tables 2 and 3 giving the positions are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/510/A10Present address: İstanbul Kültür University, Ataköy Yerleşkesi, 34156 Istanbul, Turkey

  7. The radio and infrared counterparts of the ring nebula around HD211564

    Science.gov (United States)

    Cappa, C. E.; Vasquez, J.; Pineault, S.; Cichowolski, S.

    2010-03-01

    We report the detection of the radio and infrared (IR) counterparts of the ring nebula around the WN3(h) star HD211564 (WR152), located to the south-west of the HII region Sh2132. Using radio continuum data from the Canadian Galactic Plane Survey, we identified the radio counterparts of the two concentric rings, of about 9 and 16 arcmin in radius, related to the star. After applying a filling factor f = 0.05-0.12, electron densities and ionized masses are in the range 10-16 cm-3 and 450-700Msolar, respectively. The analysis of the HI gas emission distribution allowed the identification of 5900Msolar of neutral atomic gas with velocities between -52 and -43kms-1 probably linked to the nebula. The region of the nebula is almost free of molecular gas. Only four small clumps were detected, with a total molecular mass of 790Msolar. About 310 Msolar are related to a small IR shell-like source linked to the inner ring, which is also detected in the MSX band A. An IRAS young stellar object candidate is detected in coincidence with the shell-like IR source. We suggest that the optical nebula and its neutral counterparts originated from the stellar winds from the Wolf-Rayet star and its massive progenitor, and are evolving in the envelope of a slowly expanding shell centred at of about 31 pc in radius. The bubble's energy conversion efficiency is in agreement with recent numerical analysis and with observational results.

  8. The second Herschel★-ATLAS Data Release - III: optical and near-infrared counterparts in the North Galactic Plane field

    Science.gov (United States)

    Furlanetto, C.; Dye, S.; Bourne, N.; Maddox, S.; Dunne, L.; Eales, S.; Valiante, E.; Smith, M. W.; Smith, D. J. B.; Ivison, R. J.; Ibar, E.

    2018-01-01

    This paper forms part of the second major public data release of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). In this work, we describe the identification of optical and near-infrared counterparts to the submillimetre detected sources in the 177 deg2 North Galactic Plane (NGP) field. We used the likelihood ratio method to identify counterparts in the Sloan Digital Sky Survey and in the UKIRT Imaging Deep Sky Survey within a search radius of 10 arcsec of the H-ATLAS sources with a 4σ detection at 250 μm. We obtained reliable (R ≥ 0.8) optical counterparts with r deep radio data which covers a small region of the NGP field, we found that 80 - 90 per cent of our reliable identifications are correct.

  9. Fundamental and harmonic radiation in type III solar radio bursts

    Science.gov (United States)

    Robinson, P. A.; Cairns, I. H.

    1994-01-01

    Type III solar radio bursts are investigated by modeling the propagation of the electron beam and the generation and subsequent propagation of waves to the observer. Predictions from this model are compared in detail with particle, Langmuir wave, and radio data from the International Sun Earth Explorer-3 (ISSE-3) spacecraft and with other observations to clarify the roles of fundamental and harmonic emission in type III radio bursts. Langmuir waves are seen only after the arrival of the beam, in accord with the standard theory. These waves persist after a positive beam slope is last resolved, implying that sporadic positive slopes persist for some time, unresolved but in accord with the predictions of stochastic growth theory. Local electromagnetic emission sets in only after Langmuir waves are seen, in accord with the standard theory, which relies on nonlinear processes involving Langmuir waves. In the events investigated here, fundamental radiation appears to dominate early in the event, followed and/or accompanied by harmonic radiation after the peak, with a long-lived tail of multiply scattered fundamental or harmonic emission extending long afterwards. These results are largely independent of, but generally consistent with, the conclusions of earlier works.

  10. Type III Radio Burst Duration and SEP Events

    Science.gov (United States)

    Gopalswamy, N.; Makela, P.; Xie, H.

    2010-01-01

    Long-duration (>15 min), low-frequency (SEP events of solar cycle 23. The Type III durations are distributed symmetrically at 1 MHz yielding a mean value of approximately 33 min (median = 32 min) for the large SEP events. When the SEP events with ground level enhancement (GLE,) are considered, the distribution is essentially unchanged (mean = 32 min, median = 30 min). To test the importance of type III bursts in indicating SEP events, we considered a set of six type III bursts from the same active region (AR 10588) whose durations fit the "long duration" criterion. We analyzed the coronal mass ejections (CMEs), flares, and type II radio bursts associated with the type III bursts. The CMEs were of similar speeds and the flares are also of similar size and duration. All but one of the type III bursts was not associated with a type II burst in the metric or longer wavelength domains. The burst without type II burst also lacked a solar energetic particle (SEP) event at energies >25 MeV. The 1-MHz duration of the type III burst (28 rein) is near the median value of type III durations found for gradual SEP events and ground level enhancement (GLE) events. Yet, there was no sign of SEP events. On the other hand, two other type III bursts from the same active region had similar duration but accompanied by WAVES type 11 bursts; these bursts were also accompanied by SEP events detected by SOHO/ERNE. This study suggests that the type III burst duration may not be a good indicator of an SEP event, consistent with the statistical study of Cliver and Ling (2009, ApJ ).

  11. Structure in the Radio Counterpart to the 2004 Dec 27 Giant Flare From SGR1806-20

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    Fender, Rob P.; Muxlow, T.W.B.; Garrett, M.A.; Kouveliotou, C.; Gaensler, B.M.; Garrington, S.T.; Paragi, Z.; Tudose, V.; Miller-Jones, J.C.A.; Spencer, R.E.; Wijers,; Taylor, G.B.; /Southampton U. /Jodrell Bank /JIVE, Dwingeloo /NASA, Marshall /Harvard-Smithsonian Ctr. Astrophys. /Amsterdam U., Astron. Inst. /Astron. Inst. Romanian

    2006-01-11

    The formation of an expanding, moving, and fading radio source. We report observations of this radio source with the Multi-Element Radio-Linked Interferometer Network (MERLIN) and the Very Long Baseline Array (VLBA). The observations confirm the elongation and expansion already reported based on observations at lower angular resolutions, but suggest that at early epochs the structure is not consistent with the very simplest models such as a smooth flux distribution. In particular there appears to be significant structure on small angular scales, with {approx}10% of the radio flux arising on angular scales <= 100 milliarcsec. This structure may correspond to localized sites of particle acceleration during the early phases of expansion and interaction with the ambient medium.

  12. Studying the evolution of a type III radio from the Sun up to 1 AU

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    Mann, Gottfried; Breitling, Frank; Vocks, Christian; Fallows, Richard; Melnik, Valentin; Konovalenko, Alexander

    2017-04-01

    On March 16, 2016, a type III burst was observed with the ground-based radio telescopes LOFAR and URAN-2 as well as with the radiospectrometer aboard the spacecraft WIND.It started at 80 MHz at 06:37 UT and reached 50 kHz after 23 minutes. A type III burst are considered as the radio signature of an electron beam travelling from the corona into the interplanetary space. The energetic electrons carrying the beam excites Langmuir waves, which convert into radio waves by wave-particle interaction. The relationship between the drift rate and the frequency as derived from the dynamic radio spectra reveals that the velocity of the electrons generating the radio waves of the type III burst is increasing with increasing distance from the center of the Sun.

  13. Toward Understanding the B[e] Phenomenon. III. Properties of the Optical Counterpart of IRAS 00470+6429

    Science.gov (United States)

    Miroshnichenko, A. S.; Chentsov, E. L.; Klochkova, V. G.; Zharikov, S. V.; Grankin, K. N.; Kusakin, A. V.; Gandet, T. L.; Klingenberg, G.; Kildahl, S.; Rudy, R. J.; Lynch, D. K.; Venturini, C. C.; Mazuk, S.; Puetter, R. C.; Perry, R. B.; Carciofi, A. C.; Bjorkman, K. S.; Gray, R. O.; Bernabei, S.; Polcaro, V. F.; Viotti, R. F.; Norci, L.

    2009-07-01

    FS CMa type stars are a group of Galactic objects with the B[e] phenomenon. They exhibit strong emission-line spectra and infrared excesses, which are most likely due to recently formed circumstellar dust. The group content and identification criteria were described in the first two papers of the series. In this paper we report our spectroscopic and photometric observations of the optical counterpart of IRAS 00470+6429 obtained in 2003-2008. The optical spectrum is dominated by emission lines, most of which have P Cyg type profiles. We detected significant brightness variations, which may include a regular component, and variable spectral line profiles in both shape and position. The presence of a weak Li I 6708 Å line in the spectrum suggests that the object is most likely a binary system with a B2-B3 spectral-type primary companion of a luminosity log L/L sun = 3.9 ± 0.3 and a late-type secondary companion. We estimate a distance toward the object to be 2.0 ± 0.3 kpc from the Sun. Partially based on data obtained at the 6 m BTA telescope of the Russian Academy of Sciences, 3 m IRTF, 3 m Shane telescope of the Lick Observatory, 2.7 m Harlan J. Smith and 2.1 m Otto Struve telescopes of the McDonald Observatory, 2.1 m telescope of the San Pedro Martir Observatory, 1.5 m telescope of the Loiano Observatory, and 0.8 m telescope of the Dark Sky Observatory.

  14. VizieR Online Data Catalog: Precise Radio Source Positions from Mark III VLBI (Ma+ 1990)

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    Ma, C.; Shaffer, D. B.; de Vegt, C.; Johnston, K. J.; Russell, J. L.

    1998-02-01

    This catalog contains observations from 600 Mark III VLBI experiments from conducted between 1979 to 1988. These experiments resulted in 237681 acceptable pairs of group delay and phase delay rate observations. These have been used to derive positions of 182 extra-galactic radio sources with typical formal standard errors less than 1 mas. The right ascension zero point of this reference frame has been aligned with the FK5 by using the optical positions of 28 extragalactic radio sources whose positions are on the FK5 system. Also included are the Mark III VLBI stations and a summary of the analysis configuration. (2 data files).

  15. Solar type III radio bursts modulated by homochromous Alfvén waves

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    Zhao, G. Q.; Chen, L.; Wu, D. J., E-mail: djwu@pmo.ac.cn [Purple Mountain Observatory, CAS, Nanjing 210008 (China)

    2013-12-10

    Solar type III radio bursts and their production mechanisms have been intensively studied in both theory and observation and are believed to be the most important signatures of electron acceleration in active regions. Recently, Wu et al. proposed that the electron-cyclotron maser emission (ECME) driven by an energetic electron beam could be responsible for producing type III bursts and pointed out that turbulent Alfvén waves can greatly influence the basic process of ECME via the oscillation of these electrons in the wave fields. This paper investigates effects of homochromous Alfvén waves (HAWs) on ECME driven by electron beams. Our results show that the growth rate of the O-mode wave will be significantly modulated by HAWs. We also discuss possible application to the formation of fine structures in type III bursts, such as so-called solar type IIIb radio bursts.

  16. The stimulation of auroral kilometric radiation by type III solar radio bursts

    Science.gov (United States)

    Calvert, W.

    1981-01-01

    It has been found that the onset of auroral kilometric radiation (AKR) frequently coincides with the arrival of type III solar radio bursts. Although the AKR onsets are usually abrupt and appear to be spontaneous, they sometimes develop from a discrete frequency near the leading edge of a type III burst or sometimes occur at progressively lower frequencies following that edge. From this, and the absence of the related solar electrons in specific cases, it was concluded that the incoming type III waves were sometimes responsible for stimulating auroral kilometric radiation. It was estimated that intense, isolated type III bursts were capable of stimulating AKR roughly one third of the time, and that at least ten percent of the observed AKR onsets could be attributed to these and weaker bursts, including some barely detectable by the ISEE plasma wave receivers.

  17. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VI. Radio Constraints on a Relativistic Jet and Predictions for Late-time Emission from the Kilonova Ejecta

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, K. D.; Berger, E.; Fong, W.; Williams, P. K. G.; Guidorzi, C.; Margutti, R.; Metzger, B. D.; Annis, J.; Blanchard, P. K.; Brout, D.; Brown, D. A.; Chen, H. -Y.; Chornock, R.; Cowperthwaite, P. S.; Drout, M.; Eftekhari, T.; Frieman, J.; Holz, D. E.; Nicholl, M.; Rest, A.; Sako, M.; Soares-Santos, M.; Villar, V. A.

    2017-10-16

    We present Very Large Array (VLA) and Atacama Large Millimeter/sub-millimeter Array ALMA radio observations of GW\\,170817, the first Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo gravitational wave (GW) event from a binary neutron star merger and the first GW event with an electromagnetic (EM) counterpart. Our data include the first observations following the discovery of the optical transient at both the centimeter ($13.7$ hours post merger) and millimeter ($2.41$ days post merger) bands. We detect faint emission at 6 GHz at 19.47 and 39.23 days after the merger, but not in an earlier observation at 2.46 d. We do not detect cm/mm emission at the position of the optical counterpart at frequencies of 10-97.5 GHz at times ranging from 0.6 to 30 days post merger, ruling out an on-axis short gamma-ray burst (SGRB) for energies $\\gtrsim 10^{48}$ erg. For fiducial SGRB parameters, our limits require an observer viewer angle of $\\gtrsim 20^{\\circ}$. The radio and X-ray data can be jointly explained as the afterglow emission from an SGRB with a jet energy of $\\sim 10^{49}-10^{50}$ erg that exploded in a uniform density environment with $n\\sim 10^{-4}-10^{-2}$ cm$^{-3}$, viewed at an angle of $\\sim 20^{\\circ}-40^{\\circ}$ from the jet axis. Using the results of our light curve and spectral modeling, in conjunction with the inference of the circumbinary density, we predict the emergence of late-time radio emission from the deceleration of the kilonova (KN) ejecta on a timescale of $\\sim 5-10$ years that will remain detectable for decades with next-generation radio facilities, making GW\\,170817 a compelling target for long-term radio monitoring.

  18. Variation of Langmuir wave polarization with electron beam speed in type III radio bursts

    Energy Technology Data Exchange (ETDEWEB)

    Malaspina, David M. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States); Cairns, Iver H. [School of Physics, University of Sydney, New South Wales 2006 (Australia); Ergun, Robert E. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States) and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80303 (United States)

    2013-06-13

    Observations by the twin STEREO spacecraft of in-situ electric field waveforms and radio signatures associated with type III radio bursts have demonstrated that the polarization of electron beam-driven waves near the local plasma frequency depends strongly on the speed of the driving electron beam. We expand upon a previous study by including all radio bursts with in-situ waveforms observed by STEREO in 2011. The expanded data set contains five times more radio bursts (35 up from 7) and three times as many Langmuir waves (663 up from 168). While this expanded study supports the results of the original study, that faster (slower) beam electrons drive waves with strong (weak) electric fields perpendicular to the local magnetic field, the larger data set emphasizes that the observation of strong perpendicular electric fields at high electron beam speeds is probabilistic rather than definite. This property supports the interpretation of wave polarization dependence on beam speed as Langmuir/z-mode waves shifted to small wave number through interaction with turbulent solar wind density fluctuations.

  19. High frequency ion sound waves associated with Langmuir waves in type III radio burst source regions

    Directory of Open Access Journals (Sweden)

    G. Thejappa

    2004-01-01

    Full Text Available Short wavelength ion sound waves (2-4kHz are detected in association with the Langmuir waves (~15-30kHz in the source regions of several local type III radio bursts. They are most probably not due to any resonant wave-wave interactions such as the electrostatic decay instability because their wavelengths are much shorter than those of Langmuir waves. The Langmuir waves occur as coherent field structures with peak intensities exceeding the Langmuir collapse thresholds. Their scale sizes are of the order of the wavelength of an ion sound wave. These Langmuir wave field characteristics indicate that the observed short wavelength ion sound waves are most probably generated during the thermalization of the burnt-out cavitons left behind by the Langmuir collapse. Moreover, the peak intensities of the observed short wavelength ion sound waves are comparable to the expected intensities of those ion sound waves radiated by the burnt-out cavitons. However, the speeds of the electron beams derived from the frequency drift of type III radio bursts are too slow to satisfy the needed adiabatic ion approximation. Therefore, some non-linear process such as the induced scattering on thermal ions most probably pumps the beam excited Langmuir waves towards the lower wavenumbers, where the adiabatic ion approximation is justified.

  20. A radio optical reference frame. I - Precise radio source positions determined by Mark III VLBI - Observations from 1979 to 1988 and a tie to the FK5

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    Ma, C.; Shaffer, D. B.; de Vegt, C.; Johnston, K. J.; Russell, J. L.

    1990-04-01

    Observations from 600 Mark III VLBI experiments from 1979 to 1988, resulting in 237,681 acceptable pairs of group delay and phase delay rate observations, have been used to derive positions of 182 extragalactic radio sources with typical formal standard errors less than 1 mas. The sources are distributed fairly evenly above delta = -30 deg, and 70 sources have delta greater than 0 deg. Analysis with different troposphere models, as well as internal and external comparisons, indicates that a coordinate frame defined by this set of radio sources should be reliable at the 1 mas level. The right ascension zero point of this reference frame has been aligned with the FK5 by using the optical positions of 28 extragalactic radio sources whose positions are on the FK5 system. Because of known defects in the knowledge of astronomical constants, daily nutation offsets in longitude and obliquity were determined relative to an arbitrary reference day in the set of experiments.

  1. Evidence for four- and three-wave interactions in solar type III radio emissions

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    G. Thejappa

    2013-08-01

    Full Text Available The high time resolution observations obtained by the STEREO/WAVES experiment show that in the source regions of solar type III radio bursts, Langmuir waves often occur as intense localized wave packets with short durations of only few ms. One of these wave packets shows that it is a three-dimensional field structure with WLneTe ~ 10−3, where WL is the peak energy density, and ne and Te are the electron density and temperature, respectively. For this wave packet, the conditions of the oscillating two-stream instability (OTSI and supersonic collapse are satisfied within the error range of determination of main parameters. The density cavity, observed during this wave packet indicates that its depth, width and temporal coincidence are consistent with those of a caviton, generated by the ponderomotive force of the collapsing wave packet. The spectrum of each of the parallel and perpendicular components of the wave packet contains a primary peak at fpe, two secondary peaks at fpe ± fS and a low-frequency enhancement below fS, which, as indicated by the frequency and wave number resonance conditions, and the fast Fourier transform (FFT-based tricoherence spectral peak at (fpe, fpe, fpe + fS, fpe − fS, are coupled to each other by the OTSI type of four-wave interaction (fpe is the local electron plasma frequency and fS is the frequency of ion sound waves. In addition to the primary peak at fpe, each of these spectra also contains a peak at 2fpe, which as indicated by the frequency and wave number resonance conditions, and the wavelet-based bicoherence spectral peak at (fpe, fpe, appears to correspond to the second harmonic electromagnetic waves generated as a result of coalescence of oppositely propagating sidebands excited by the OTSI. Thus, these observations for the first time provide combined evidence that (1 the OTSI and related strong turbulence processes play a significant role in the stabilization of the electron beam, (2 the coalescence

  2. LOFAR tied-array imaging of Type III solar radio bursts

    NARCIS (Netherlands)

    Morosan, D.E.; et al., [Unknown; Hessels, J.W.T.; Markoff, S.

    2014-01-01

    Context. The Sun is an active source of radio emission which is often associated with energetic phenomena such as solar flares and coronal mass ejections (CMEs). At low radio frequencies (<100 MHz), the Sun has not been imaged extensively because of the instrumental limitations of previous radio

  3. LOFAR tied-array imaging of Type III solar radio bursts

    NARCIS (Netherlands)

    Morosan, D.E.; Gallagher, P.T.; Zucca, P.; Fallows, R.; Carley, E.P.; Mann, G.; Bisi, M.M.; Kerdraon, A.; Avruch, I.M.; Bentum, Marinus Jan; Bernardi, G.; Best, P.; Bonafede, A.; Bregman, J.; Breitling, F.

    2014-01-01

    Context: The Sun is an active source of radio emission which is often associated with energetic phenomena such as solar flares and coronal mass ejections (CMEs). At low radio frequencies (<100 MHz), the Sun has not been imaged extensively because of the instrumental limitations of previous radio

  4. The Comparative Characteristic of Components in the Iiib-Iii Pairs According to the Observation Data Obtained by Radio Telescope URAN-2

    Science.gov (United States)

    Brazhenko, A. I.; Melnik, V. N.; Konovalenko, A. A.; Dorovskiy, V. V.; Vashchishin, R. V.; Frantsuzenko, A. V.; Rucker, G.

    In this paper we analyze the properties of type IIIb and type III bursts in IIIb-III pairs observed by radio telescope URAN-2 at frequencies 16-32 MHz. We discuss pro and contra of harmonic phenomenon of decameter IIIb-III pairs.

  5. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta

    Science.gov (United States)

    Nicholl, M.; Berger, E.; Kasen, D.; Metzger, B. D.; Elias, J.; Briceño, C.; Alexander, K. D.; Blanchard, P. K.; Chornock, R.; Cowperthwaite, P. S.; Eftekhari, T.; Fong, W.; Margutti, R.; Villar, V. A.; Williams, P. K. G.; Brown, W.; Annis, J.; Bahramian, A.; Brout, D.; Brown, D. A.; Chen, H.-Y.; Clemens, J. C.; Dennihy, E.; Dunlap, B.; Holz, D. E.; Marchesini, E.; Massaro, F.; Moskowitz, N.; Pelisoli, I.; Rest, A.; Ricci, F.; Sako, M.; Soares-Santos, M.; Strader, J.

    2017-10-01

    We present optical and ultraviolet spectra of the first electromagnetic counterpart to a gravitational-wave (GW) source, the binary neutron star merger GW170817. Spectra were obtained nightly between 1.5 and 9.5 days post-merger, using the Southern Astrophysical Research and Magellan telescopes; the UV spectrum was obtained with the Hubble Space Telescope at 5.5 days. Our data reveal a rapidly fading blue component (T≈ 5500 K at 1.5 days) that quickly reddens; spectra later than ≳ 4.5 days peak beyond the optical regime. The spectra are mostly featureless, although we identify a possible weak emission line at ˜7900 Å at t≲ 4.5 days. The colors, rapid evolution, and featureless spectrum are consistent with a “blue” kilonova from polar ejecta comprised mainly of light r-process nuclei with atomic mass number A≲ 140. This indicates a sightline within {θ }{obs}≲ 45^\\circ of the orbital axis. Comparison to models suggests ˜0.03 M ⊙ of blue ejecta, with a velocity of ˜ 0.3c. The required lanthanide fraction is ˜ {10}-4, but this drops to < {10}-5 in the outermost ejecta. The large velocities point to a dynamical origin, rather than a disk wind, for this blue component, suggesting that both binary constituents are neutron stars (as opposed to a binary consisting of a neutron star and a black hole). For dynamical ejecta, the high mass favors a small neutron star radius of ≲ 12 km. This mass also supports the idea that neutron star mergers are a major contributor to r-process nucleosynthesis.

  6. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta

    Energy Technology Data Exchange (ETDEWEB)

    Nicholl, M.; Berger, E.; Kasen, D.; Metzger, B. D.; Elias, J.; Briceño, C.; Alexander, K. D.; Blanchard, P. K.; Chornock, R.; Cowperthwaite, P. S.; Eftekhari, T.; Fong, W.; Margutti, R.; Villar, V. A.; Williams, P. K. G.; Brown, W.; Annis, J.; Bahramian, A.; Brout, D.; Brown, D. A.; Chen, H. -Y.; Clemens, J. C.; Dennihy, E.; Dunlap, B.; Holz, D. E.; Marchesini, E.; Massaro, F.; Moskowitz, N.; Pelisoli, I.; Rest, A.; Ricci, F.; Sako, M.; Soares-Santos, M.; Strader, J.

    2017-10-16

    We present optical and ultraviolet spectra of the first electromagnetic counterpart to a gravitational wave (GW) source, the binary neutron star merger GW170817. Spectra were obtained nightly between 1.5 and 9.5 days post-merger, using the SOAR and Magellan telescopes; the UV spectrum was obtained with the \\textit{Hubble Space Telescope} at 5.5 days. Our data reveal a rapidly-fading blue component ($T\\approx5500$ K at 1.5 days) that quickly reddens; spectra later than $\\gtrsim 4.5$ days peak beyond the optical regime. The spectra are mostly featureless, although we identify a possible weak emission line at $\\sim 7900$ \\AA\\ at $t\\lesssim 4.5$ days. The colours, rapid evolution and featureless spectrum are consistent with a "blue" kilonova from polar ejecta comprised mainly of light $r$-process nuclei with atomic mass number $A\\lesssim 140$. This indicates a sight-line within $\\theta_{\\rm obs}\\lesssim 45^{\\circ}$ of the orbital axis. Comparison to models suggests $\\sim0.03$ M$_\\odot$ of blue ejecta, with a velocity of $\\sim 0.3c$. The required lanthanide fraction is $\\sim 10^{-4}$, but this drops to $<10^{-5}$ in the outermost ejecta. The large velocities point to a dynamical origin, rather than a disk wind, for this blue component, suggesting that both binary constituents are neutron stars (as opposed to a binary consisting of a neutron star and a black hole). For dynamical ejecta, the high mass favors a small neutron star radius of $\\lesssim 12$ km. This mass also supports the idea that neutron star mergers are a major contributor to $r$-process nucleosynthesis.

  7. MINIFILAMENT ERUPTION AS THE SOURCE OF A BLOWOUT JET, C-CLASS FLARE, AND TYPE-III RADIO BURST

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Junchao; Jiang, Yunchun; Yang, Jiayan; Li, Haidong; Xu, Zhe, E-mail: hjcsolar@ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming, 650216 (China); Center for Astronomical Mega-Science, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing, 100012 (China)

    2017-01-20

    We report a strong minifilament eruption associated with Geostationary Operational Environmental Satellite C1.6 flare and WIND type-III radio burst. The minifilament, which lies at the periphery of active region 12259, is detected by H α images from the New Vacuum Solar Telescope. The minifilament undergoes a partial and then a full eruption. Simultaneously, two co-spatial jets are successively observed in extreme ultraviolet images from the Solar Dynamic Observatory . The first jet exhibits a typical fan-spine geometry, suggesting that the co-spatial minifilament is possibly embedded in magnetic fields with a fan-spine structure. However, the second jet displays blowout morphology when the entire minifilament erupts upward, leaving behind a hard X-ray emission source in the base. Differential emission measure analyses show that the eruptive region is heated up to about 4 MK during the fan-spine jet, while up to about 7 MK during the blowout jet. In particular, the blowout jet is accompanied by an interplanetary type-III radio burst observed by WIND /WAVES in the frequency range from above 10 to 0.1 MHz. Hence, the minifilament eruption is correlated with the interplanetary type-III radio burst for the first time. These results not only suggest that coronal jets can result from magnetic reconnection initiated by erupting minifilaments with open fields, but also shed light on the potential influence of minifilament eruption on interplanetary space.

  8. RAiSE III: 3C radio AGN energetics and composition

    Science.gov (United States)

    Turner, Ross J.; Shabala, Stanislav S.; Krause, Martin G. H.

    2018-03-01

    Kinetic jet power estimates based exclusively on observed monochromatic radio luminosities are highly uncertain due to confounding variables and a lack of knowledge about some aspects of the physics of active galactic nuclei (AGNs). We propose a new methodology to calculate the jet powers of the largest, most powerful radio sources based on combinations of their size, lobe luminosity, and shape of their radio spectrum; this approach avoids the uncertainties encountered by previous relationships. The outputs of our model are calibrated using hydrodynamical simulations and tested against independent X-ray inverse-Compton measurements. The jet powers and lobe magnetic field strengths of radio sources are found to be recovered using solely the lobe luminosity and spectral curvature, enabling the intrinsic properties of unresolved high-redshift sources to be inferred. By contrast, the radio source ages cannot be estimated without knowledge of the lobe volumes. The monochromatic lobe luminosity alone is incapable of accurately estimating the jet power or source age without knowledge of the lobe magnetic field strength and size, respectively. We find that, on average, the lobes of the Third Cambridge Catalogue of Radio Sources (3C) have magnetic field strengths approximately a factor three lower than the equipartition value, inconsistent with equal energy in the particles and the fields at the 5σ level. The particle content of 3C radio lobes is discussed in the context of complementary observations; we do not find evidence favouring an energetically dominant proton population.

  9. The changing source of X-ray reflection in the radio-intermediate Seyfert 1 galaxy III Zw 2

    Science.gov (United States)

    Gonzalez, A. G.; Waddell, S. G. H.; Gallo, L. C.

    2018-03-01

    We report on X-ray observations of the radio-intermediate, X-ray bright Seyfert 1 galaxy, III Zw 2, obtained with XMM-Newton, Suzaku, and Swift over the past 17 yr. The source brightness varies significantly over yearly time-scales, but more modestly over periods of days. Pointed observations with XMM-Newton in 2000 and Suzaku in 2011 show spectral differences despite comparable X-ray fluxes. The Suzaku spectra are consistent with a power-law continuum and a narrow Gaussian emission feature at ˜6.4 keV, whereas the earlier XMM-Newton spectrum requires a broader Gaussian profile and soft-excess below ˜2 keV. A potential interpretation is that the primary power-law emission, perhaps from a jet base, preferentially illuminates the inner accretion disc in 2000, but the distant torus in 2011. The interpretation could be consistent with the hypothesized precessing radio jet in III Zw 2 that may have originated from disc instabilities due to an ongoing merging event.

  10. Evidence for Ultra-Fast Outflows in Radio-Quiet AGNs: III - Location and Energetics

    Science.gov (United States)

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Braito, V.

    2012-01-01

    Using the results of a previous X-ray photo-ionization modelling of blue-shifted Fe K absorption lines on a sample of 42 local radio-quiet AGNs observed with XMM-Newton, in this letter we estimate the location and energetics of the associated ultrafast outflows (UFOs). Due to significant uncertainties, we are essentially able to place only lower/upper limits. On average, their location is in the interval approx.0.0003-0.03pc (approx.10(exp 2)-10(exp 4)tau(sub s) from the central black hole, consistent with what is expected for accretion disk winds/outflows. The mass outflow rates are constrained between approx.0.01- 1 Stellar Mass/y, corresponding to approx. or >5-10% of the accretion rates. The average lower-upper limits on the mechanical power are logE(sub K) approx. or = 42.6-44.6 erg/s. However, the minimum possible value of the ratio between the mechanical power and bolometric luminosity is constrained to be comparable or higher than the minimum required by simulations of feedback induced by winds/outflows. Therefore, this work demonstrates that UFOs are indeed capable to provide a significant contribution to the AGN r.osmological feedback, in agreement with theoretical expectations and the recent observation of interactions between AGN outflows and the interstellar medium in several Seyferts galaxies .

  11. Dynamics of Langmuir and ion-sound waves in type III solar radio sources

    Science.gov (United States)

    Robinson, P. A.; Willes, A. J.; Cairns, I. H.

    1993-01-01

    The study traces the evolution of Langmuir and ion-sound waves in type III sources, incorporating linear growth, linear damping, and nonlinear electrostatic decay. Improved estimates are obtained for the wavenumber range of growing waves and the nonlinear coupling coefficient for the decay process. It is shown that the conditions in the solar wind do not allow a steady state to be attained; instead, bursty linear and nonlinear interactions take place, consistent with the highly inhomogeneous and impulsive waves actually observed. Nonlinear growth is found to be rapid enough to saturate the growth of the parent Langmuir waves in the available interaction time. The competing processes of nonlinear wave collapse and quasi-linear relaxation are discussed, and it is concluded that neither is responsible for the saturation of Langmuir growth.

  12. Socio-Economic Aspects of National Communication Systems: III. Radio Broadcasting in Venezuela. Communication and Society, 12.

    Science.gov (United States)

    Capriles, Oswaldo; And Others

    The third in a series that examines the role of radio broadcasting in the process of socioeconomic and cultural change in three countries with different types of broadcasting organization--Austria, Czechoslovakia, and Venezuela--this volume focuses on Venezuela. An overview of radio broadcasting in Venezuela describes various aspects and provides…

  13. Chandra studies of the globular cluster 47 Tucanae: A deeper X-ray source catalogue, five new X-ray counterparts to millisecond radio pulsars, and new constraints to r-mode instability window

    Science.gov (United States)

    Bhattacharya, Souradeep; Heinke, Craig O.; Chugunov, Andrey I.; Freire, Paulo C. C.; Ridolfi, Alessandro; Bogdanov, Slavko

    2017-12-01

    We combined Chandra ACIS observations of the globular cluster 47 Tucanae (hereafter, 47 Tuc) from 2000, 2002, and 2014-15 to create a deeper X-ray source list, and study some of the faint radio millisecond pulsars (MSPs) present in this cluster. We have detected 370 X-ray sources within the half-mass radius (2'.79) of the cluster, 81 of which are newly identified, by including new data and using improved source detection techniques. The majority of the newly identified sources are in the crowded core region, indicating cluster membership. We associate five of the new X-ray sources with chromospherically active BY Dra or W UMa variables identified by Albrow et al. (2001). We present alternative positions derived from two methods, centroiding and image reconstruction, for faint, crowded sources. We are able to extract X-ray spectra of the recently discovered MSPs 47 Tuc aa, 47 Tuc ab, the newly timed MSP 47 Tuc Z, and the newly resolved MSPs 47 Tuc S and 47 Tuc F. Generally, they are well fit by black body or neutron star atmosphere models, with temperatures, luminosities and emitting radii similar to those of other known MSPs in 47 Tuc, though 47 Tuc aa and 47 Tuc ab reach lower X-ray luminosities. We limit X-ray emission from the full surface of the rapidly spinning (542 Hz) MSP 47 Tuc aa, and use this limit to put an upper bound for amplitude of r-mode oscillations in this pulsar as α<2.5×10^{-9}$ and constrain the shape of the r-mode instability window.

  14. The VLA Nascent Disk And Multiplicity Survey of Perseus Protostars (VANDAM). III. Extended Radio Emission from Protostars in Perseus

    Science.gov (United States)

    Tychoniec, Łukasz; Tobin, John J.; Karska, Agata; Chandler, Claire; Dunham, Michael M.; Li, Zhi-Yun; Looney, Leslie W.; Segura-Cox, Dominique; Harris, Robert J.; Melis, Carl; Sadavoy, Sarah I.

    2018-01-01

    Centimeter continuum emission from protostars offers insight into the innermost part of the outflows, as shock-ionized gas produces free–free emission. We observed a complete population of Class 0 and I protostars in the Perseus molecular cloud at 4.1 and 6.4 cm with resolution and sensitivity superior to previous surveys. From a total of 71 detections, eight sources exhibit resolved emission at 4.1 cm and/or 6.4 cm. In this paper, we focus on this subsample, analyzing their spectral indices along the jet and their alignment with respect to the large-scale molecular outflow. Spectral indices for fluxes integrated toward the position of the protostar are consistent with free–free thermal emission. The value of the spectral index along a radio jet decreases with distance from the protostar. For six sources, emission is well aligned with the outflow central axis, showing that we observe the ionized base of the jet. This is not the case for two sources, where we note misalignment of the emission with respect to the large-scale outflow. This might indicate that the emission does not originate in the radio jet, but rather in an ionized outflow cavity wall or disk surface. For five of the sources, the spectral indices along the jet decrease well below the thermal free–free limit of ‑0.1 with > 2σ significance. This is indicative of synchrotron emission, meaning that high-energy electrons are being produced in the outflows close to the disk. This result can have far-reaching implications for the chemical composition of the embedded disks.

  15. Radio optical reference frame. 6: Additional source positions in the northern hemisphere

    Science.gov (United States)

    Fey, A. L.; Russell, J. L.; de Vegt, C.; Zacharias, N.; Johnston, K. J.; Ma, C.; Hall, D. M.; Holdenried, E. R.

    1994-01-01

    Radio and optical positions for northern hemisphere extragalactic sources are reported. Milliarcsecond (mas) accurate radio positions of 106 sources north of -2 deg declination are derived from Mark III Very Long Baseline Interferometry (VLBI) observations taken during ten experiments from 1990 January through 1990 October. The results presented supplement an ongoing project to define and maintain an all-sky radio/optical reference frame of 400 or more extragalactic sources with mas accurate radio and optical positions. Radio positions for 34 new sources are presented along with improved radio positions for 72 sources already in the reference frame catalog. An additional nine sources have been determined to be unsuitable reference frame objects. Radio observations of nine calibration sources tie the new positions to the existing catalogue. The radio positions of the new sources have formal mean errors of approximately 0.7 mas in right ascension and approximately 1.0 mas in declination. Sources for which we report improved radio positions now have formal mean errors of approximately 0.5 mas in both coordinates, an improvement in some cases by as much as 75%. Positions in the FK5 system have also been obtained for the optical counterparts of an additional five northern hemisphere radio sources using prime focus plates from the Kitt Peak National Observatory's 4 m telescope and a Ritchey-Chretien focus plate from the Calar Alto 2.2 m telescope. The optical positions have internal accuracies of about 0.03 sec and differ from the radio positions by about 0.07 sec on the average.

  16. Verifying a candidate counterpart to gravitational waves

    Science.gov (United States)

    Kasliwal, Mansi

    2017-08-01

    With advances in sensitivity of gravitational wave interferometers, the direct detection of neutron star mergers should be imminent. Identification of an electromagnetic counterpart would enable a wealth of astrophysics and answer the long-standing question of whether neutron star mergers are the missing cosmic mines of heavy elements synthesized by the r-process. We will be searching for a fast-fading optical counterpart with the new Zwicky Transient Facility at Palomar Observatory. Here, we propose to use HST/WFC3 to look for infrared emission from a single, most-promising candidate optical counterpart. The infrared emission would serve as a direct diagnostic of the radioactive decay of heavy elements.

  17. Radio Journalism.

    Science.gov (United States)

    Bittner, John R.; Bittner, Denise A.

    This book, a how-to-do-it guide for the novice and the professional alike, deals with several aspects of radio journalism: producing documentaries, preparing and announcing radio news, ethics and responsibility, regulation of radio journalism, and careers. It traces the history and growth of radio news, shows its impact on the public, and…

  18. Electromagnetic Counterparts to Black Hole Mergers

    Science.gov (United States)

    Schnittman, Jeremy D.

    2011-01-01

    During the final moments of a binary black hole (BH) merger, the gravitational wave (GW) luminosity of the system is greater than the combined electromagnetic (EM) output of the entire observable universe. However, the extremely weak coupling between GWs and ordinary matter makes these waves very difficult to detect directly. Fortunately, the inspirating BH system will interact strongly-on a purely Newtonian level-with any surrounding material in the host galaxy, and this matter can in turn produce unique EM signals detectable at Earth. By identifying EM counterparts to GW sources, we will be able to study the host environments of the merging BHs, in turn greatly expanding the scientific yield of a mission like LISA. Here we present a comprehensive review of the recent literature on the subject of EM counterparts, as well as a discussion of the theoretical and observational advances required to fully realize the scientific potential of the field.

  19. The Hunt for a Counterpart to GW150914

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    On 14 September 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) in a pre-operative testing state at the time detected its first sign of gravitational-waves. The LIGO team sprang into action, performing data-quality checks on this unexpected signal. Within two days, they had sent a notification to 63 observing teams at observatories representing the entire electromagnetic spectrum, from radio to gamma-ray wavelengths.Illustration of a binary neutron star merger. The neutron stars 1) inspiral, 2) can produce a short gamma-ray burst, 3) can fling out hot, radioactive material in the form of a kilonova, and 4) form a massive neutron star or black hole with a possible remnant debris disk around it. [NASA/ESA/A. Feild (STScI)]Thus began the very first hunt for an electromagnetic counterpart to a detected gravitational wave signal.What were they looking for?As two compact objects in a binary system merge, the system is expected to emit energy in the form of gravitational waves. If both of the compact objects are black holes, were unlikely to see any electromagnetic radiation in the process, unless the merger is occurring in an (improbable) environment filled with gas and dust.But if one or both of the two compact objects is a neutron star, then there are a number of electromagnetic signatures that could occur due to energetic outflows. If a relativistic jet forms, we could see a short gamma-ray burst and X-ray, optical, and radio afterglows. Sub-relativistic outflows could produce optical and near-infrared signals, or a radio blast wave.Timeline of observations of GW150914, separated by wavelength band, and relative to the time of the gravitational-wave trigger. The top row shows LIGO information releases. The bottom four rows show high-energy, optical, near-infrared, and radio observations, respectively. Click for a closer look! [Abbott et al. 2016]Surprise SignalSince LIGO and Virgo (LIGOs European counterpart), wereprimarily expecting to detect

  20. Radio Mariackie

    OpenAIRE

    Tytko, Marek Mariusz

    1993-01-01

    Tekst dotyczy początków katolickiego Radia Mariackiego w Krakowie w 1993 r. The text concerns the begining of the Mariackie Radio [The Mariackie Broadcasting, the Maria's Radio Station, the Maria's Broadcasting, the Maria's Radio) in Cracow 1993.

  1. Kilonova Counterparts of Binary Neutron Star Mergers

    Science.gov (United States)

    Metzger, Brian

    2018-01-01

    The merger of a binary neutron star is accompanied by the ejection of neutron-rich matter into space at velocities up to several tenths that of light, which synthesizes rare heavy isotopes through the rapid neutron capture process (r-process). The radioactive decay of these nuclei was predicted by Metzger et al. (2010) to power an optical transient roughly 1000 times more luminous than a classical nova (a "kilonova"), which is among the most promising electromagnetic counterparts to accompany gravitational wave signal from the merger. I will describe how the luminosities, color, and spectra of the kilonova emission inform the properties of the merging binary (neutron star masses/radii and inclination angle) and the long sought origin of the heaviest elements in the Universe. Results will be discussed in the context of recent discoveries by Advanced LIGO/Virgo.

  2. Finding the Electromagnetic Counterparts of Standard Sirens

    Science.gov (United States)

    Kocsis, B.; Frei, Z.; Haiman, Z.; Menou, K.

    The gravitational waves (GWs) emitted during the coalescence of supermassive black holes (SMBHs) will be detectable with the future Laser Interferometric Space Antenna (LISA). The direction and distance can be determined from the accumulated GW signal with a precision that increases rapidly in the final stages of the inspiral. We find that for M = (105 - 107)M⊙ near z = 1 the angular uncertainty decreases under 1° at least several hours before the plunge, allowing a targeted electromagnetic (EM) observation of the final stages of the merger with a wide field instrument. We then calculate the size of the final, three dimensional error volume. Under the plausible assumption that SMBH-SMBH mergers are accompanied by gas accretion leading to Eddington-limited quasar activity, we find that many cases this error volume will contain at most a single quasar for M = (105 - 107) M⊙ near z = 1. This will allow a straightforward test of the hypothesis that GW events are accompanied by bright quasar activity. The identification and observation of counterparts would allow unprecedented tests of the physics of MBH accretion, such as precision-measurements of the Eddington ratio. They would clarify the role of gas as a catalyst in SMBH coalescences, and would also offer an alternative method to constrain cosmological parameters.

  3. Electromagnetic Counterparts of Neutron Star Mergers

    Science.gov (United States)

    Metzger, Brian

    2011-09-01

    The most promising astrophysical sources of gravitational waves (GWs) for ground-based interferometers such as Advanced LIGO are the inspiral and merger of binary neutron star (NS) and black hole systems. Maximizing the benefits of a GW detection will require identifying a coincident electromagnetic (EM) counterpart. One possible source of bright EM emission is a gamma-ray burst (GRB), powered by accretion following the merger. However, for typical viewers outside the opening angle of the GRB jet, prompt emission may be difficult to detect. Another source of isotropic EM emission from NS mergers is a supernova-like optical transient (`kilo-nova'), powered by the radioactive decay of heavy elements synthesized in the ejecta . I will present the first calculations of the optical transients from NS mergers that self consistently determine the radioactive heating using a nuclear reaction network and which determine the resulting light curve with a Monte Carlo radiation transfer calculation. I will compare the predicted brightness and duration of the kilo-nova to the expected off-axis (`orphan') afterglow emission, in order to assess the optimal EM follow-up strategy following a future GW detection.

  4. Discovery of near-ultraviolet counterparts to millisecond pulsars in the globular cluster 47 Tucanae

    Science.gov (United States)

    Rivera-Sandoval, L. E.; van den Berg, M.; Heinke, C. O.; Cohn, H. N.; Lugger, P. M.; Freire, P.; Anderson, J.; Serenelli, A. M.; Althaus, L. G.; Cool, A. M.; Grindlay, J. E.; Edmonds, P. D.; Wijnands, R.; Ivanova, N.

    2015-11-01

    We report the discovery of the likely white dwarf companions to radio millisecond pulsars 47 Tuc Q and 47 Tuc S in the globular cluster 47 Tucanae. These blue stars were found in near-ultraviolet images from the Hubble Space Telescope for which we derived accurate absolute astrometry, and are located at positions consistent with the radio coordinates to within 0.016 arcsec (0.2σ). We present near-ultraviolet and optical colours for the previously identified companion to millisecond pulsar 47 Tuc U, and we unambiguously confirm the tentative prior identifications of the optical counterparts to 47 Tuc T and 47 Tuc Y. For the latter, we present its radio-timing solution for the first time. We find that all five near-ultraviolet counterparts have U300 - B390 colours that are consistent with He white dwarf cooling models for masses ˜0.16-0.3 M⊙ and cooling ages within ˜0.1-6 Gyr. The Hα - R625 colours of 47 Tuc U and 47 Tuc T indicate the presence of a strong Hα absorption line, as expected for white dwarfs with an H envelope.

  5. Automated Volumetric Modulated Arc Therapy Treatment Planning for Stage III Lung Cancer: How Does It Compare With Intensity-Modulated Radio Therapy?

    Energy Technology Data Exchange (ETDEWEB)

    Quan, Enzhuo M. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chang, Joe Y.; Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Xia Tingyi [Department of Radiation Oncology, Beijing 301 Hospital, Beijing (China); Yuan Zhiyong [Department of Radiation Oncology, Tianjin Medical University Cancer Hospital and Institute, Tianjin (China); Liu Hui [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, Zhongshan University Hospital, Guangzhou (China); Li, Xiaoqiang; Wages, Cody A.; Mohan, Radhe [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhang Xiaodong, E-mail: xizhang@mdanderson.org [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-09-01

    Purpose: To compare the quality of volumetric modulated arc therapy (VMAT) or intensity-modulated radiation therapy (IMRT) plans generated by an automated inverse planning system with that of dosimetrist-generated IMRT treatment plans for patients with stage III lung cancer. Methods and Materials: Two groups of 8 patients with stage III lung cancer were randomly selected. For group 1, the dosimetrists spent their best effort in designing IMRT plans to compete with the automated inverse planning system (mdaccAutoPlan); for group 2, the dosimetrists were not in competition and spent their regular effort. Five experienced radiation oncologists independently blind-reviewed and ranked the three plans for each patient: a rank of 1 was the best and 3 was the worst. Dosimetric measures were also performed to quantitatively evaluate the three types of plans. Results: Blind rankings from different oncologists were generally consistent. For group 1, the auto-VMAT, auto-IMRT, and manual IMRT plans received average ranks of 1.6, 2.13, and 2.18, respectively. The auto-VMAT plans in group 1 had 10% higher planning tumor volume (PTV) conformality and 24% lower esophagus V70 (the volume receiving 70 Gy or more) than the manual IMRT plans; they also resulted in more than 20% higher complication-free tumor control probability (P+) than either type of IMRT plans. The auto- and manual IMRT plans in this group yielded generally comparable dosimetric measures. For group 2, the auto-VMAT, auto-IMRT, and manual IMRT plans received average ranks of 1.55, 1.75, and 2.75, respectively. Compared to the manual IMRT plans in this group, the auto-VMAT plans and auto-IMRT plans showed, respectively, 17% and 14% higher PTV dose conformality, 8% and 17% lower mean lung dose, 17% and 26% lower mean heart dose, and 36% and 23% higher P+. Conclusions: mdaccAutoPlan is capable of generating high-quality VMAT and IMRT treatment plans for stage III lung cancer. Manual IMRT plans could achieve quality

  6. DISCOVERY OF A TRANSIENT GAMMA-RAY COUNTERPART TO FRB 131104

    Energy Technology Data Exchange (ETDEWEB)

    DeLaunay, J. J.; Murase, K.; Mészáros, P.; Keivani, A.; Messick, C.; Mostafá, M. A.; Oikonomou, F.; Tešić, G.; Turley, C. F. [Department of Physics, Pennsylvania State University, University Park, PA 16802 (United States); Fox, D. B., E-mail: jjd330@psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

    2016-11-20

    We report our discovery in Swift satellite data of a transient gamma-ray counterpart (3.2 σ confidence) to the fast radio burst (FRB) FRB 131104, the first such counterpart to any FRB. The transient has a duration T {sub 90} ≳ 100 s and a fluence S{sub γ} ≈ 4 × 10{sup −6} erg cm{sup −2}, increasing the energy budget for this event by more than a billion times; at the nominal z ≈ 0.55 redshift implied by its dispersion measure, the burst’s gamma-ray energy output is E{sub γ} ≈ 5 × 10{sup 51} erg. The observed radio to gamma-ray fluence ratio for FRB 131104 is consistent with a lower limit we derive from Swift observations of another FRB, which is not detected in gamma-rays, and with an upper limit previously derived for the brightest gamma-ray flare from SGR 1806−20, which was not detected in the radio. X-ray, ultraviolet, and optical observations beginning two days after the FRB do not reveal any associated afterglow, supernova, or transient; Swift observations exclude association with the brightest 65% of Swift gamma-ray burst (GRB) X-ray afterglows, while leaving the possibility of an associated supernova at much more than 10% the FRB’s nominal distance, D ≳ 320 Mpc, largely unconstrained. Transient high-luminosity gamma-ray emission arises most naturally in a relativistic outflow or shock breakout, such as, for example, from magnetar flares, GRBs, relativistic supernovae, and some types of galactic nuclear activity. Our discovery thus bolsters the case for an extragalactic origin for some FRBs and suggests that future rapid-response observations might identify long-lived counterparts, resolving the nature of these mysterious phenomena and realizing their promise as probes of cosmology and fundamental physics.

  7. What is the Most Promising Electromagnetic Counterpart of a Neutron Star Binary Merger?

    Science.gov (United States)

    Metzger, B. D.; Berger, E.

    2012-02-01

    The final inspiral of double neutron star and neutron-star-black-hole binaries are likely to be detected by advanced networks of ground-based gravitational wave (GW) interferometers. Maximizing the science returns from such a discovery will require the identification of an electromagnetic counterpart. Here we critically evaluate and compare several possible counterparts, including short-duration gamma-ray bursts (SGRBs), "orphan" optical and radio afterglows, and day-long optical transients powered by the radioactive decay of heavy nuclei synthesized in the merger ejecta ("kilonovae"). We assess the promise of each counterpart in terms of four "Cardinal Virtues": detectability, high fraction, identifiability, and positional accuracy. Taking into account the search strategy for typical error regions of tens of square degrees, we conclude that SGRBs are the most useful to confirm the cosmic origin of a few GW events, and to test the association with neutron star mergers. However, for the more ambitious goal of localizing and obtaining redshifts for a large sample of GW events, kilonovae are instead preferred. Off-axis optical afterglows are detectable for at most tens of percent of events, while radio afterglows are promising only for energetic relativistic ejecta in a high-density medium. Our main recommendations are: (1) an all-sky gamma-ray satellite is essential for temporal coincidence detections, and for GW searches of gamma-ray-triggered events; (2) the Large Synoptic Survey Telescope should adopt a one-day cadence follow-up strategy, ideally with 0.5 hr per pointing to cover GW error regions; and (3) radio searches should focus on the relativistic case, which requires observations for a few months.

  8. Enzymatic and non-enzymatic antioxidant status in stage (III) human oral squamous cell carcinoma and treated with radical radio therapy: influence of selenium supplementation.

    Science.gov (United States)

    Elango, Narchonai; Samuel, Shila; Chinnakkannu, Panneerselvam

    2006-11-01

    Oxidative stress is implicated in oral carcinogenesis and has been found to be aggravated during radiotherapy. A great deal of attention has been focused on the possible therapeutic implications of selenium as a potent antioxidant. We determined whether selenium supplementation to radiation treated oral cancer patients render improvement in the antioxidant status against oxidative stress. Blood samples were collected from stage (III) oral cancer patients before initiating radiotherapy (Group B) (n=63) and this group is bifurcated into Group C-patients given radiotherapy alone (n=27) and Group D-patients given radiotherapy and supplemented with selenium (400 mug/day for 6 months) (n=36). Both Group C and D were followed up for 6 months. We evaluated the plasma selenium concentration, non-enzymatic system including GSH, vitamins E, C, A and ceruloplasmin and enzymatic antioxidant system including superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase. The concentrations of selenium, all non-enzymatic antioxidants and the activities of enzymatic antioxidants were found to be lowered in oral cancer patients (Group B), compared to normal (Group A) (p<0.05). Similar decrease in the concentration of selenium and antioxidants status was observed in radiotherapy group (Group C) (p<0.05). On the contrary, selenium group (Group D) showed marked increase in the concentrations of selenium and antioxidant status at 6 months compared to radiation group (Group C) (p<0.05). The observed result represents the antioxidant property of selenium through the improvement of antioxidant defense system. Selenium supplementation could be of great interest in protecting cells against oxidative stress.

  9. The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102

    Energy Technology Data Exchange (ETDEWEB)

    Tendulkar, S. P.; Kaspi, V. M. [Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Bassa, C. G.; Adams, E. A. K.; Hessels, J. W. T.; Maddox, N. [ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, NL-7990 AA Dwingeloo (Netherlands); Cordes, J. M.; Chatterjee, S. [Cornell Center for Astrophysics and Planetary Science and Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Bower, G. C. [Academia Sinica Institute of Astronomy and Astrophysics, 645 N. A’ohoku Place, Hilo, HI 96720 (United States); Law, C. J. [Department of Astronomy and Radio Astronomy Lab, University of California, Berkeley, CA 94720 (United States); Bogdanov, S. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Burke-Spolaor, S.; Butler, B. J.; Demorest, P. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Lazio, T. J. W. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Marcote, B.; Paragi, Z. [Joint Institute for VLBI ERIC, Postbus 2, NL-7990 AA Dwingeloo (Netherlands); McLaughlin, M. A. [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506 (United States); Ransom, S. M. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Scholz, P., E-mail: shriharsh@physics.mcgill.ca, E-mail: bassa@astron.nl [National Research Council of Canada, Herzberg Astronomy and Astrophysics, Dominion Radio Astrophysical Observatory, P.O. Box 248, Penticton, BC V2A 6J9 (Canada); and others

    2017-01-10

    The precise localization of the repeating fast radio burst (FRB 121102) has provided the first unambiguous association (chance coincidence probability p ≲ 3 × 10{sup −4}) of an FRB with an optical and persistent radio counterpart. We report on optical imaging and spectroscopy of the counterpart and find that it is an extended (0.″6–0.″8) object displaying prominent Balmer and [O iii] emission lines. Based on the spectrum and emission line ratios, we classify the counterpart as a low-metallicity, star-forming, m{sub r′} = 25.1 AB mag dwarf galaxy at a redshift of z = 0.19273(8), corresponding to a luminosity distance of 972 Mpc. From the angular size, the redshift, and luminosity, we estimate the host galaxy to have a diameter ≲4 kpc and a stellar mass of M {sub *} ∼ (4–7) × 10{sup 7} M {sub ⊙}, assuming a mass-to-light ratio between 2 to 3 M {sub ⊙} L {sub ⊙} {sup −1}. Based on the H α flux, we estimate the star formation rate of the host to be 0.4 M {sub ⊙} yr{sup −1} and a substantial host dispersion measure (DM) depth ≲324 pc cm{sup −3}. The net DM contribution of the host galaxy to FRB 121102 is likely to be lower than this value depending on geometrical factors. We show that the persistent radio source at FRB 121102’s location reported by Marcote et al. is offset from the galaxy’s center of light by ∼200 mas and the host galaxy does not show optical signatures for AGN activity. If FRB 121102 is typical of the wider FRB population and if future interferometric localizations preferentially find them in dwarf galaxies with low metallicities and prominent emission lines, they would share such a preference with long gamma-ray bursts and superluminous supernovae.

  10. Solar Radio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves (100?s of MHz to 10?s of GHz). Variations in...

  11. A dichotomy in radio jet orientations

    NARCIS (Netherlands)

    Kleijn, Gijs Verdoes; de Zeeuw, P. T.

    2006-01-01

    We examine the relative orientations of radio jets, central dust and stars in low-power (i.e., FR I and FR I/II) radio galaxies. We use the position angles of jet and dust to constrain the three-dimensional angle theta(DJ) between jet and dust. For galaxies with filamentary dust 'lanes' (which tend

  12. XMM-Newton observations of the massive colliding wind binary and non-thermal radio emitter CygOB2#8A [O6If + O5.5III(f)

    Science.gov (United States)

    De Becker, M.; Rauw, G.; Sana, H.; Pollock, A. M. T.; Pittard, J. M.; Blomme, R.; Stevens, I. R.; van Loo, S.

    2006-09-01

    We report on the results of four XMM-Newton observations separated by about ten days from each other of CygOB2#8A [O6If + O5.5III(f)]. This massive colliding wind binary is a very bright X-ray emitter - one of the first X-ray emitting O-stars discovered by the Einstein satellite - as well as a confirmed non-thermal radio emitter whose binarity was discovered quite recently. The X-ray spectrum between 0.5 and 10.0keV is essentially thermal, and is best fitted with a three-component model with temperatures of about 3, 9 and 20MK. The X-ray luminosity corrected for the interstellar absorption is rather large, i.e. about 1034ergs-1. Compared to the `canonical' LX/Lbol ratio of O-type stars, CygOB2#8A was a factor of 19-28 overluminous in X-rays during our observations. The EPIC spectra did not reveal any evidence for the presence of a non-thermal contribution in X-rays. This is not unexpected considering that the simultaneous detections of non-thermal radiation in the radio and soft X-ray (below 10.0keV) domains is unlikely. Our data reveal a significant decrease in the X-ray flux from apastron to periastron with an amplitude of about 20 per cent. Combining our XMM-Newton results with those from previous ROSAT-PSPC and ASCA-SIS observations, we obtain a light curve suggesting a phase-locked X-ray variability. The maximum emission level occurs around phase 0.75, and the minimum is probably seen shortly after the periastron passage. Using hydrodynamic simulations of the wind-wind collision, we find a high X-ray emission level close to phase 0.75, and a minimum at periastron as well. The high X-ray luminosity, the strong phase-locked variability and the spectral shape of the X-ray emission of CygOB2#8A revealed by our investigation point undoubtedly to X-ray emission dominated by colliding winds. Based on observations with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member states and the USA (NASA). E-mail: debecker

  13. THE VARIABLE NEAR-INFRARED COUNTERPART OF THE MICROQUASAR GRS 1758–258

    Energy Technology Data Exchange (ETDEWEB)

    Luque-Escamilla, Pedro L. [Departamento de Ingeniería Mecánica y Minera, EPSJ, Universidad de Jaén, Campus Las Lagunillas s/n, A3-008, 23071 Jaén (Spain); Martí, Josep [Departamento de Física, EPSJ, Universidad de Jaén, Campus Las Lagunillas s/n, A3-420, 23071 Jaén (Spain); Muñoz-Arjonilla, Álvaro J., E-mail: peter@ujaen.es, E-mail: jmarti@ujaen.es, E-mail: ajmunoz@ujaen.es [Grupo de Investigación FQM-322, Universidad de Jaén, Campus Las Lagunillas s/n, A3-065, 23071 Jaén (Spain)

    2014-12-10

    We present a new study of the microquasar system GRS 1758–258 in the near-infrared domain based on archival observations with the Hubble Space Telescope and the NICMOS camera. In addition to confirming the near-infrared counterpart pointed out by Muñoz-Arjonilla et al., we show that this object displays significant photometric variability. From its average magnitudes, we also find that GRS 1758–258 fits well within the correlation between the optical/near-infrared and X-ray luminosity known to exist for low-mass, black-hole candidate X-ray binaries in a hard state. Moreover, the spectral energy distribution built using all radio, near-infrared, and X-ray data available closest in time to the NICMOS observations can be reasonably interpreted in terms of a self-absorbed radio jet and an irradiated accretion disk model around a stellar-mass black hole. All these facts match the expected behavior of a compact binary system and strengthen our confidence in the counterpart identification.

  14. Unification of Radio Galaxies and their Accretion Jet Properties ...

    Indian Academy of Sciences (India)

    Abstract. We investigate the relation between black hole mass, Mbh, and jet power, Qjet, for a sample of BL Lacs and radio quasars. We find that BL Lacs are separated from radio quasars by the FR I/II dividing line in Mbh–Qjet plane, which strongly supports the unification scheme of FR. I/BL Lac and FR II/radio quasar.

  15. Radio astronomy

    CERN Document Server

    Alder, Berni

    1975-01-01

    Methods in Computational Physics, Volume 14: Radio Astronomy is devoted to the role of the digital computer both as a control device and as a calculator in addressing problems related to galactic radio noise. This volume contains four chapters and begins with a technical description of the hardware and the special data-handling problems of using radioheliography, with an emphasis on a selection of observational results obtained with the Culgoora radioheliograph and their significance to solar physics and to astrophysics in general. The subsequent chapter examines interstellar dispersion, i

  16. Digitale radio

    NARCIS (Netherlands)

    Schiphorst, Roelof; Zondervan, L.

    2007-01-01

    Als eerste in Europa heeft Nederland begin december 2006 de omschakeling van analoge naar digitale ethertelevisie gemaakt. Voor de analoge FM-radio is er ook een digitale variant, T-DAB. T-DAB staat voor 'Terrestrial Digital Audio Broadcasting'. Dit artikel gaat verder in op deze techniek en de

  17. The Radio JOVE Project - Shoestring Radio Astronomy

    Science.gov (United States)

    Thieman, J.; Flagg, R.; Greenman, W.; Higgins, C.; Reyes, F.; Sky, J.

    2010-01-01

    Radio JOVE is an education and outreach project intended to give students and other interested individuals hands-on experience in learning radio astronomy. They can do this through building a radio telescope from a relatively inexpensive kit that includes the parts for a receiver and an antenna as well as software for a computer chart recorder emulator (Radio Skypipe) and other reference materials

  18. Space Telecommunications Radio System STRS Cognitive Radio

    Science.gov (United States)

    Briones, Janette C.; Handler, Louis M.

    2013-01-01

    Radios today are evolving from awareness toward cognition. A software defined radio (SDR) provides the most capability for integrating autonomic decision making ability and allows the incremental evolution toward a cognitive radio. This cognitive radio technology will impact NASA space communications in areas such as spectrum utilization, interoperability, network operations, and radio resource management over a wide range of operating conditions. NASAs cognitive radio will build upon the infrastructure being developed by Space Telecommunication Radio System (STRS) SDR technology. This paper explores the feasibility of inserting cognitive capabilities in the NASA STRS architecture and the interfaces between the cognitive engine and the STRS radio. The STRS architecture defines methods that can inform the cognitive engine about the radio environment so that the cognitive engine can learn autonomously from experience, and take appropriate actions to adapt the radio operating characteristics and optimize performance.

  19. Radio emission from embryonic superluminous supernova remnants

    Science.gov (United States)

    Omand, Conor M. B.; Kashiyama, Kazumi; Murase, Kohta

    2018-02-01

    It has been widely argued that Type-I superluminous supernovae (SLSNe-I) are driven by powerful central engines with a long-lasting energy injection after the core-collapse of massive progenitors. One of the popular hypotheses is that the hidden engines are fast-rotating pulsars with a magnetic field of B ˜ 1013-1015 G. Murase, Kashiyama & Mészáros proposed that quasi-steady radio/submm emission from non-thermal electron-positron pairs in nascent pulsar wind nebulae can be used as a relevant counterpart of such pulsar-driven supernovae (SNe). In this work, focusing on the nascent SLSN-I remnants, we examine constraints that can be placed by radio emission. We show that the Atacama Large Millimeter/submillimetre Array can detect the radio nebula from SNe at DL ˜ 1 Gpc in a few years after the explosion, while the Jansky Very Large Array can also detect the counterpart in a few decades. The proposed radio follow-up observation could solve the parameter degeneracy in the pulsar-driven SN model for optical/UV light curves, and could also give us clues to young neutron star scenarios for SLSNe-I and fast radio bursts.

  20. THE SCUBA-2 COSMOLOGY LEGACY SURVEY: MULTIWAVELENGTH COUNTERPARTS TO 10{sup 3} SUBMILLIMETER GALAXIES IN THE UKIDSS-UDS FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chian-Chou; Smail, Ian; Ma, Cheng-Jiun; Simpson, James M.; Swinbank, A. Mark [Centre for Extragalactic Astronomy, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Ivison, Rob J.; Arumugam, Vinodiran; Mortlock, Alice; Dunlop, James S.; Michałowski, Michał J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Almaini, Omar; Conselice, Christopher J.; Hartley, Will G. [University of Nottingham, School of Physics and Astronomy, Nottingham, NG7 2RD (United Kingdom); Geach, James E. [Center for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Simpson, Chris [Astrophysics Research Institute, Liverpool John Moores University, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Aretxaga, Itziar [Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Luis Enrique Erro 1, Sta. Ma. Tonantzintla, Puebla (Mexico); Blain, Andrew [Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Chapman, Scott C. [Department of Physics and Atmospheric Science, Dalhousie University, 6310 Coburg Road, Halifax, NS B3H 4R2 (Canada); Farrah, Duncan [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Halpern, Mark [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); and others

    2016-04-01

    We present multiwavelength identifications for the counterparts of 1088 submillimeter sources detected at 850 μm in the SCUBA-2 Cosmology Legacy Survey study of the UKIRT Infrared Deep Sky Survey-Ultra-Deep Survey (UDS) field. By utilizing an Atacama Large Millimeter Array (ALMA) pilot study on a subset of our bright SCUBA-2 sample as a training set, along with the deep optical–near-infrared (OIR) data available in this field, we develop a novel technique, Optical–IR Triple Color (OIRTC), using z − K, K − [3.6], [3.6] − [4.5] colors to select the candidate submillimeter galaxy (SMG) counterparts. By combining radio identification and the OIRTC technique, we find counterpart candidates for 80% of the Class = 1 ≥ 4σ SCUBA-2 sample, defined as those that are covered by both radio and OIR imaging and the base sample for our scientific analyses. Based on the ALMA training set, we expect the accuracy of these identifications to be 82% ± 20%, with a completeness of 69% ± 16%, essentially as accurate as the traditional p-value technique but with higher completeness. We find that the fraction of SCUBA-2 sources having candidate counterparts is lower for fainter 850 μm sources, and we argue that for follow-up observations sensitive to SMGs with S{sub 850} ≳ 1 mJy across the whole ALMA beam, the fraction with multiple counterparts is likely to be >40% for SCUBA-2 sources at S{sub 850} ≳ 4 mJy. We find that the photometric redshift distribution for the SMGs is well fit by a lognormal distribution, with a median redshift of z = 2.3 ± 0.1. After accounting for the sources without any radio and/or OIRTC counterpart, we estimate the median redshift to be z = 2.6 ± 0.1 for SMGs with S{sub 850} > 1 mJy. We also use this new large sample to study the clustering of SMGs and the far-infrared properties of the unidentified submillimeter sources by stacking their Herschel SPIRE far-infrared emission.

  1. A Search for TeV Counterparts to BATSE Gamma-Ray Bursts

    Science.gov (United States)

    Connanughton, V.; Akerlof, C. W.; Barthelmy, S.; Biller, S.; Boyle, P.; Fishman, G. J.; Meegan, C. A.

    1997-01-01

    Intense effort has gone into the observation of optical, radio, and X-ray gamma-ray burst (GRB) counterparts, either simultaneous to the burst or as quasi-steady lingering remnants. Here we report on a similar study at higher energies of 250 GeV and above using ground-based telescopes. The recent technical advances represented by the atmospheric Cherenkov imaging technique (Cawley & Weekes 1995) have opened up the field of gamma-ray astronomy above 250 GeV and raised the possibility that these techniques can be used with excellent fluence sensitivity in exploring the GRB phenomenon. Observations by the Whipple collaboration of nine BATSE positions, one acquired within 2 minutes of the reported BATSE burst time, using coordinates distributed through the BATSE Coordinates Distribution Network (BACODINE) are reported. No evidence of TeV emission is found, and upper limits to the high-energy delayed or extended emission of observed candidates are calculated.

  2. A search for distant radio-loud quasars in the CLASS survey : three new radio-selected quasars at z > 4

    NARCIS (Netherlands)

    Snellen, IAG; McMahon, RG; Dennett-Thorpe, J; Jackson, N; Mack, KH; Xanthopoulos, E

    2001-01-01

    We report on the search for distant radio-loud quasars in the Cosmic Lens All Sky Survey (CLASS) of flat spectrum radio sources with S-5GHz > 30 mJy. Unresolved optical counterparts were selected from APM scans of POSS-I plates, with e <19.0 and red o - e > 2.0 colours, in an effective area of

  3. Radio Galaxy Zoo: cosmological alignment of radio sources

    Science.gov (United States)

    Contigiani, O.; de Gasperin, F.; Miley, G. K.; Rudnick, L.; Andernach, H.; Banfield, J. K.; Kapińska, A. D.; Shabala, S. S.; Wong, O. I.

    2017-11-01

    We study the mutual alignment of radio sources within two surveys, Faint Images of the Radio Sky at Twenty-centimetres (FIRST) and TIFR GMRT Sky Survey (TGSS). This is done by producing two position angle catalogues containing the preferential directions of respectively 30 059 and 11 674 extended sources distributed over more than 7000 and 17 000 deg2. The identification of the sources in the FIRST sample was performed in advance by volunteers of the Radio Galaxy Zoo (RGZ) project, while for the TGSS sample it is the result of an automated process presented here. After taking into account systematic effects, marginal evidence of a local alignment on scales smaller than 2.5 deg is found in the FIRST sample. The probability of this happening by chance is found to be less than 2 per cent. Further study suggests that on scales up to 1.5 deg the alignment is maximal. For one third of the sources, the RGZ volunteers identified an optical counterpart. Assuming a flat Λ cold dark matter cosmology with Ω _m = 0.31, Ω _Λ = 0.69, we convert the maximum angular scale on which alignment is seen into a physical scale in the range [19, 38] Mpc h_{70}^{-1}. This result supports recent evidence reported by Taylor and Jagannathan of radio jet alignment in the 1.4 deg2 ELAIS N1 field observed with the Giant Metrewave Radio Telescope. The TGSS sample is found to be too sparsely populated to manifest a similar signal.

  4. The X-ray counterpart to the gravitational-wave event GW170817

    Science.gov (United States)

    Troja, E.; Piro, L.; van Eerten, H.; Wollaeger, R. T.; Im, M.; Fox, O. D.; Butler, N. R.; Cenko, S. B.; Sakamoto, T.; Fryer, C. L.; Ricci, R.; Lien, A.; Ryan, R. E.; Korobkin, O.; Lee, S.-K.; Burgess, J. M.; Lee, W. H.; Watson, A. M.; Choi, C.; Covino, S.; D’Avanzo, P.; Fontes, C. J.; González, J. Becerra; Khandrika, H. G.; Kim, J.; Kim, S.-L.; Lee, C.-U.; Lee, H. M.; Kutyrev, A.; Lim, G.; Sánchez-Ramírez, R.; Veilleux, S.; Wieringa, M. H.; Yoon, Y.

    2017-11-01

    A long-standing paradigm in astrophysics is that collisions—or mergers—of two neutron stars form highly relativistic and collimated outflows (jets) that power γ-ray bursts of short (less than two seconds) duration. The observational support for this model, however, is only indirect. A hitherto outstanding prediction is that gravitational-wave events from such mergers should be associated with γ-ray bursts, and that a majority of these bursts should be seen off-axis, that is, they should point away from Earth. Here we report the discovery observations of the X-ray counterpart associated with the gravitational-wave event GW170817. Although the electromagnetic counterpart at optical and infrared frequencies is dominated by the radioactive glow (known as a ‘kilonova’) from freshly synthesized rapid neutron capture (r-process) material in the merger ejecta, observations at X-ray and, later, radio frequencies are consistent with a short γ-ray burst viewed off-axis. Our detection of X-ray emission at a location coincident with the kilonova transient provides the missing observational link between short γ-ray bursts and gravitational waves from neutron-star mergers, and gives independent confirmation of the collimated nature of the γ-ray-burst emission.

  5. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VIII. A Comparison to Cosmological Short-duration Gamma-Ray Bursts

    Science.gov (United States)

    Fong, W.; Berger, E.; Blanchard, P. K.; Margutti, R.; Cowperthwaite, P. S.; Chornock, R.; Alexander, K. D.; Metzger, B. D.; Villar, V. A.; Nicholl, M.; Eftekhari, T.; Williams, P. K. G.; Annis, J.; Brout, D.; Brown, D. A.; Chen, H.-Y.; Doctor, Z.; Diehl, H. T.; Holz, D. E.; Rest, A.; Sako, M.; Soares-Santos, M.

    2017-10-01

    We present a comprehensive comparison of the properties of the radio through X-ray counterpart of GW170817 and the properties of short-duration gamma-ray bursts (GRBs). For this effort, we utilize a sample of 36 short GRBs spanning a redshift range of z≈ 0.12{--}2.6 discovered over 2004-2017. We find that the counterpart to GW170817 has an isotropic-equivalent luminosity that is ≈ 3000 times less than the median value of on-axis short GRB X-ray afterglows, and ≳104 times less than that for detected short GRB radio afterglows. Moreover, the allowed jet energies and particle densities inferred from the radio and X-ray counterparts to GW170817 and on-axis short GRB afterglows are remarkably similar, suggesting that viewing angle effects are the dominant, and perhaps only, difference in their observed radio and X-ray behavior. From comparison to previous claimed kilonovae following short GRBs, we find that the optical and near-infrared (NIR) counterpart to GW170817 is comparatively under-luminous by a factor of ≈ 3{--}5, indicating a range of kilonova luminosities and timescales. A comparison of the optical limits following short GRBs on ≲ 1 day timescales also rules out a “blue” kilonova of comparable optical isotropic-equivalent luminosity in one previous short GRB. Finally, we investigate the host galaxy of GW170817, NGC 4993, in the context of short GRB host galaxy stellar population properties. We find that NGC 4993 is superlative in terms of its large luminosity, old stellar population age, and low star formation rate compared to previous short GRB hosts. Additional events within the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo volume will be crucial in delineating the properties of the host galaxies of neutron star-neutron star (NS-NS) mergers, and connecting them to their cosmological counterparts.

  6. Real-time Automatic Search for Multi-wavelength Counterparts of DWF Transients

    Science.gov (United States)

    Murphy, Christopher; Cucchiara, Antonino; Andreoni, Igor; Cooke, Jeff; Hegarty, Sarah

    2018-01-01

    The Deeper Wider Faster (DWF) survey aims to find and classify the fastest transients in the Universe. DWF utilizes the Dark Energy Camera (DECam), collecting a continuous sequence of 20s images over a 3 square degree field of view.Once an interesting transient is detected during DWF observations, the DWF collaboration has access to several facilities for rapid follow-up in multiple wavelengths (from gamma to radio).An online web tool has been designed to help with real-time visual classification of possible astrophysical transients in data collected by the DWF observing program. The goal of this project is to create a python-based code to improve the classification process by querying several existing archive databases. Given the DWF transient location and search radius, the developed code will extract a list of possible counterparts and all available information (e.g. magnitude, radio fluxes, distance separation).Thanks to this tool, the human classifier can make a quicker decision in order to trigger the collaboration rapid-response resources.

  7. VARIABILITY OF OPTICAL COUNTERPARTS IN THE CHANDRA GALACTIC BULGE SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Britt, C. T.; Hynes, R. I.; Johnson, C. B.; Baldwin, A.; Collazzi, A.; Gossen, L. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Jonker, P. G.; Torres, M. A. P. [SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Nelemans, G. [Department of Astrophysics, IMAPP, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen (Netherlands); Maccarone, T. [Department of Physics, Texas Tech University, Box 41051, Science Building, Lubbock, TX 79409-1051 (United States); Steeghs, D.; Greiss, S. [Astronomy and Astrophysics, Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Heinke, C. [Department of Physics, University of Alberta, CCIS 4-183, Edmonton, AB T6G 2E1 (Canada); Bassa, C. G. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Villar, A. [Department of Physics, Massachussettes Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307 (United States); Gabb, M. [Department of Physics, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991 (United States)

    2014-09-01

    We present optical light curves of variable stars consistent with the positions of X-ray sources identified with the Chandra X-ray Observatory for the Chandra Galactic Bulge Survey (GBS). Using data from the Mosaic-II instrument on the Blanco 4 m Telescope at CTIO, we gathered time-resolved photometric data on timescales from ∼2 hr to 8 days over the 3/4 of the X-ray survey containing sources from the initial GBS catalog. Among the light curve morphologies we identify are flickering in interacting binaries, eclipsing sources, dwarf nova outbursts, ellipsoidal variations, long period variables, spotted stars, and flare stars. Eighty-seven percent of X-ray sources have at least one potential optical counterpart. Twenty-seven percent of these candidate counterparts are detectably variable; a much greater fraction than expected for randomly selected field stars, which suggests that most of these variables are real counterparts. We discuss individual sources of interest, provide variability information on candidate counterparts, and discuss the characteristics of the variable population.

  8. Evidence for Infrared-faint Radio Sources as z > 1 Radio-loud Active Galactic Nuclei

    Science.gov (United States)

    Huynh, Minh T.; Norris, Ray P.; Siana, Brian; Middelberg, Enno

    2010-02-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey which have no observable mid-infrared counterpart in the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6-70 μm) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the spectral energy distribution of these objects shows that they are consistent with high-redshift (z >~ 1) active galactic nuclei.

  9. Optical Counterparts of Undetermined Type -Ray Active Galactic ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Taking advantage of data from radio and X-ray wavelengths, which we expect to be produced together with -rays, providing a much better source localization potential, we focused our attention on a sample of -ray Blazar Candidates of Undetermined type (BCUs), starting a campaign of optical ...

  10. Auroral kilometric radiation triggered by type II solar radio bursts

    Science.gov (United States)

    Calvert, W.

    1985-01-01

    The previously-reported triggering of auroral kilometric radiation (AKR) during type III solar radio bursts was attributed to the incoming radio waves rather than other aspects of the burst's causative solar flare. This conclusion has now been confirmed by ISEE-1 and ISEE-3 observations showing AKR which seems to have been triggered also by a subsequent type II solar radio burst, up to eleven hours after the flare.

  11. Unification of Radio Galaxies and their Accretion Jet Properties

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We investigate the relation between black hole mass, bh, and jet power, jet, for a sample of BL Lacs and radio quasars. We find that BL Lacs are separated from radio quasars by the FR I/II dividing line in bh-jet plane, which strongly supports the unification scheme of FR I/BL Lac and FR II/radio ...

  12. Electromagnetic counterparts to structured jets from gravitational wave detected mergers

    Science.gov (United States)

    Lamb, Gavin P.; Kobayashi, Shiho

    2017-12-01

    We show the peak magnitude for orphan afterglows from the jets of gravitational wave (GW) detected black hole/neutron star - neutron star (BH/NS-NS) mergers highly depend on the jet half-opening angle θj. Short γ-ray bursts (GRBs) with a homogeneous jet structure and θj > 10°, the orphan afterglow viewed at the typical inclination for a GW detected event, 38°, are brighter at optical frequencies than the comparable macronova emission. Structured jets, where the energetics and Lorentz factor Γ vary with angle from the central axis, may have low-Γ components where the prompt emission is suppressed; GW electromagnetic (EM) counterparts may reveal a population of failed-GRB orphan afterglows. Using a Monte Carlo method assuming an NS-NS detection limit we show the fraction of GW-EM counterparts from homogeneous, two-component, power-law structured and Gaussian jets where the variable structure models include a wide low energy and Γ component: for homogeneous jets, with a θj = 6° and typical short GRB parameters, we find r-band magnitude mr ≤ 21 counterparts for ∼13.6 per cent of GW detected mergers; where jet structure extends to a half-opening angle of 25°, two-component jets produce mr ≤ 21 counterparts in ∼30 per cent of GW detected mergers, power-law structured-jets result in ∼37 per cent and Gaussian jets with our parameters ∼13 per cent. We show the features in the light curves from orphan afterglows can be used to indicate the presence of extended structure.

  13. Search for Gravitational Wave Counterparts with Fermi GBM

    Science.gov (United States)

    Hui, C. M.

    2017-01-01

    The progenitor of short gamma-ray bursts (GRBs) is believed to be the merger of two compact objects. This type of events will also produce gravitational waves. Since the gravitational waves discovery by LIGO, the search for a joint detection with an electromagnetic counterpart has been ongoing. Fermi GBM detects approximately 40 short GRBs per year, and we have been expanding our search looking for faint events in the GBM data that did not trigger onboard.

  14. Properties and environment of Radio Emitting Galaxies in the VLA-zCOSMOS survey

    OpenAIRE

    Bardelli, S.; Schinnerer, E.; Smolcic, V.; Zamorani, G.; Zucca, E.; Mignoli, M; Halliday, C.; Kovac, K.; Ciliegi, P.; Caputi, K.; Koekemoer, A. M.; Bongiorno, A.; Bondi, M.; Bolzonella, M.; Vergani, D.

    2009-01-01

    Aims. We investigate the properties and the environment of radio sources with optical counterparts from the combined VLA-COSMOS and zCOSMOS samples. The advantage of this sample is the availability of optical spectroscopic informations, high quality redshifts, and accurate density determination. Methods. By comparing the star formation rates estimated from the optical spectral energy distribution with those based on the radio luminosity, we divide the radio sources in to three fam...

  15. A rapid search for the counterpart to an active magnetar

    Science.gov (United States)

    Levan, Andrew

    2016-10-01

    We propose to obtain a fast response observation of a magnetar undergoing an active period. Utilizing rapid, deep, diffraction limited observations with WFC3 we will maximize the chances of obtaining the IR detection of the magnetar. This in turn yields unique constraints on emission mechanisms, enables the measurement of dynamics (e.g. via proper motion) and can associate the magnetar with a given structure (e.g. young cluster or supernova remnant) in the galaxy. The association with a cluster provides means of measuring the stellar age, in turn informing the stellar properties (e.g. mass) of the magnetar progenitors. We have demonstrated the success of this approach with the detection of the counterpart of SGR 1935+2154 with a magnitude (during bursting activity) of F140W(AB) 25.5, a level extremely challenging to detect variability in from the ground, requiring multiple nights of adaptive optics imaging in typical conditions. Indeed, our observations will be senstive to counterparts significantly fainter than it is possible to detect from any ground based observatory. These observations will allow us to break through the observational barrier that has so far prevented us from detecting counterparts to more than two-thirds of magnetar candidates. With these observations we will construct a fuller picture of magnetars, the routes to their creation, and their role as cosmic engines across the Universe.

  16. Radio frequency detection assembly and method for detecting radio frequencies

    Science.gov (United States)

    Cown, Steven H.; Derr, Kurt Warren

    2010-03-16

    A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

  17. Finding the Electromagnetic Counterparts of Cosmological Standard Sirens

    Science.gov (United States)

    Kocsis, Bence; Frei, Zsolt; Haiman, Zoltán; Menou, Kristen

    2006-01-01

    The gravitational waves (GWs) emitted during the coalescence of supermassive black holes (SMBHs) in the mass range ~104-107 Msolar/(1+z) will be detectable out to high redshifts with the future Laser Interferometer Space Antenna (LISA). The distance and direction to these ``standard sirens'' can be inferred directly from the GW signal, with a precision that depends on the masses, spins, and geometry of the merging system. In a given cosmology, the LISA-measured luminosity distance translates into a redshift shell. We calculate the size and shape of the corresponding three-dimensional error volume in which an electromagnetic counterpart to a LISA event could be found, taking into account errors in the background cosmology (as expected by the time LISA flies), weak gravitational lensing (de)magnification due to inhomogeneities along the line of sight, and potential source-peculiar velocities. Weak-lensing errors largely exceed other sources of uncertainties (by a factor of ~7 for typical sources at z=1). Under the plausible assumption that SMBH-SMBH mergers are accompanied by gas accretion leading to Eddington-limited quasar activity, we then compute the number of quasars that would be found in a typical three-dimensional LISA error volume, as a function of BH mass and event redshift. Low redshifts offer the best opportunities to identify quasar counterparts to cosmological standard sirens. For mergers of ~4×(105-107) Msolar SMBHs, the LISA error volume will typically contain a single near-Eddington quasar at z~1. If SMBHs are spinning rapidly, the error volume is smaller and may contain a unique quasar out to redshift z~3. This will allow a straightforward test of the hypothesis that GW events are accompanied by bright quasar activity and, if the hypothesis proves correct, will guarantee the identification of a unique quasar counterpart to a LISA event, with a B-band luminosity of LB~(1010-1011) Lsolar. Robust counterpart identifications would allow unprecedented

  18. Multiband counterparts of two eclipsing ultraluminous X-ray sources in M 51

    Science.gov (United States)

    Urquhart, R.; Soria, R.; Johnston, HM; Pakull, MW; Motch, C.; Schwope, A.; Miller-Jones, JCA; Anderson, GE

    2018-01-01

    We present the discovery and interpretation of ionized nebulae around two ultraluminous X-ray sources in M 51; both sources share the rare property of showing X-ray eclipses by their companion stars, and are therefore prime targets for follow-up studies. Using archival Hubble Space Telescope images, we found an elongated, 100-pc-long emission-line structure associated with one X-ray source (CXOM51 J132940.0+471237; ULX-1 for simplicity), and a more circular, ionized nebula at the location of the second source (CXOM51 J132939.5+471244; ULX-2 for simplicity). We observed both nebulae with the Large Binocular Telescope's Multi-Object Double Spectrograph. From our analysis of the optical spectra, we argue that the gas in the ULX-1 bubble is shock-ionized, consistent with the effect of a jet with a kinetic power of ≈2 × 1039 erg s-1. Additional X-ray photo-ionization may also be present, to explain the strength of high-ionization lines such as He II λ4686 and [Ne V] λ3426. On the other hand, the emission lines from the ULX-2 bubble are typical for photoionization by normal O stars suggesting that the nebula is actually an H II region not physically related to the ULX but is simply a chance alignment. From archival Very Large Array data, we also detect spatially extended, steep-spectrum radio emission at the location of the ULX-1 bubble (consistent with its jet origin), but no radio counterpart for ULX-2 (consistent with the lack of shock-ionized gas around that source).

  19. Capability of detecting ultraviolet counterparts of gravitational waves with GLUV

    Science.gov (United States)

    Ridden-Harper, Ryan; Tucker, B. E.; Sharp, R.; Gilbert, J.; Petkovic, M.

    2017-12-01

    With the discovery of gravitational waves (GWs), attention has turned towards detecting counterparts to these sources. In discussions on counterpart signatures and multimessenger follow-up strategies to the GW detections, ultraviolet (UV) signatures have largely been neglected, due to UV facilities being limited to SWIFT, which lacks high-cadence UV survey capabilities. In this paper, we examine the UV signatures from merger models for the major GW sources, highlighting the need for further modelling, while presenting requirements and a design for an effective UV survey telescope. Using the u΄-band models as an analogue, we find that a UV survey telescope requires a limiting magnitude of m_{u^' }}(AB)≈ 24 to fully complement the aLIGO range and sky localization. We show that a network of small, balloon-based UV telescopes with a primary mirror diameter of 30 cm could be capable of covering the aLIGO detection distance from ˜60 to 100 per cent for BNS events and ˜40 per cent for the black hole and a neutron star events. The sensitivity of UV emission to initial conditions suggests that a UV survey telescope would provide a unique data set, which can act as an effective diagnostic to discriminate between models.

  20. Cat Mammary Tumors: Genetic Models for the Human Counterpart

    Directory of Open Access Journals (Sweden)

    Filomena Adega

    2016-08-01

    Full Text Available The records are not clear, but Man has been sheltering the cat inside his home for over 12,000 years. The close proximity of this companion animal, however, goes beyond sharing the same roof; it extends to the great similarity found at the cellular and molecular levels. Researchers have found a striking resemblance between subtypes of feline mammary tumors and their human counterparts that goes from the genes to the pathways involved in cancer initiation and progression. Spontaneous cat mammary pre-invasive intraepithelial lesions (hyperplasias and neoplasias and malignant lesions seem to share a wide repertoire of molecular features with their human counterparts. In the present review, we tried to compile all the genetics aspects published (i.e., chromosomal alterations, critical cancer genes and their expression regarding cat mammary tumors, which support the cat as a valuable alternative in vitro cell and animal model (i.e., cat mammary cell lines and the spontaneous tumors, respectively, but also to present a critical point of view of some of the issues that really need to be investigated in future research.

  1. FAST RADIO BURSTS AND RADIO TRANSIENTS FROM BLACK HOLE BATTERIES

    Energy Technology Data Exchange (ETDEWEB)

    Mingarelli, Chiara M. F. [TAPIR, MC 350-17, California Institute of Technology, Pasadena, CA 91125 (United States); Levin, Janna [Institute for Strings, Cosmology and Astroparticle Physics (ISCAP), Columbia University, New York, NY 10027 (United States); Lazio, T. Joseph W. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2015-12-01

    Most black holes (BHs) will absorb a neutron star (NS) companion fully intact without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally, the luminosity was expected to be in high-energy X-rays or gamma-rays, however, we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs; millisecond-scale radio transients) NS–BH coalescence rates are too low to make these a primary FRB source. Instead, we propose that the transients form a FRB sub-population, distinguishable by a double peak with a precursor. The rapid ramp-up in luminosity manifests as a precursor to the burst which is 20%–80% as luminous given 0.5 ms timing resolution. The main burst arises from the peak luminosity before the merger. The post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS–BH pairs are especially desirable for ground-based gravitational wave (GW) observatories since the pair might not otherwise be detected, with EM counterparts greatly augmenting the scientific leverage beyond the GW signal. The EM signal’s ability to break degeneracies in the parameters encoded in the GW and probe the NS magnetic field strength is quite valuable, yielding insights into open problems in NS magnetic field decay.

  2. Kenya's Radio Language Arts Project: evaluation results.

    Science.gov (United States)

    Oxford, R L

    1985-01-01

    The Kenya Radio Language Arts Project (RLAP), which has just been completed, documents the effectiveness of interactive radio-based educational instruction. Analyses in the areas of listening, reading, speaking, and writing show that children in radio classrooms consistently scored better than children in nonradio classrooms in every test. An evaluation of the project was conducted with the assistance of the Center for Applied Linguistics (CAL). Evaluation results came from a variety of sources, including language tests, observations, interviews, demographic and administrative records, and an attitude survey. A large proportion of the project's students were considerably transient. Only 22% of the total student population of 3908 were "normal progression" students -- that is, they advanced regularly through their education during the life of the project. Students who moved from the area, failed a standard (grade), dropped out, or were otherwise untrackable, comprised the remaining 78% of the total. 7 districts were included in the project. Tests were developed for listening and reading in Standards 1, 2, and 3 and in speaking and writing in Standards 2 and 3. The achievement tests were based on the official Kenya curriculum for those standards, so as to measure achievement against the curriculum. Nearly all the differences were highly significant statistically, with a probability of less than 1 in 1000 that the findings could have occurred by chance. Standard 1 radio students scored nearly 8 points higher than did their counterparts in the control group. Standard 2 and 3 radio students outperformed the control students by 4 points. The radio group consistently outperformed the control group in reading, writing, and speaking. Unstructured interviews and observations were conducted by the RLAP field staff. Overwhelmingly positive attitudes about the project prevailed among project teachers and headmasters. The data demonstrate that RLAP works. In fact, it works so

  3. Impact of cognitive radio on radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Boonstra, A.J.; Baan, W.A.

    2010-01-01

    The introduction of new communication techniques requires an increase in the efficiency of spectrum usage. Cognitive radio is one of the new techniques that fosters spectrum efficiency by using unoccupied frequency spectrum for communications. However, cognitive radio will increase the transmission

  4. Radio Stalin as an example of the Czech pirate radio

    OpenAIRE

    Prágrová, Šárka

    2017-01-01

    Diploma thesis "Radio Stalin as an example of Czech piracy radio broadcast" is aimed to complexly present radio station Radio Stalin which was broadcasting in October 1990 in Prague. Radio Stalin is presented in the context of events of that time and related changes in politics, economy, society and media and in the context of piracy radio broadcast. First of all the emphasis is put on media transformation and changes in legislative framework of radio broadcasting after 1989. Radio Stalin is ...

  5. Leaving home [radio drama

    OpenAIRE

    Lawrence, Conan

    2014-01-01

    A 50 minute Radio Drama tracing the stories of Amy, Edie and Barnard Beechey as they prepare for the First World War and the changes it brings to their lives. Broadcast on BBC Radio Lincolnshire, 4th August, 2014.

  6. Fast Radio Bursts

    Indian Academy of Sciences (India)

    28

    FRBs) which were first discovered a decade ago. Following an introduction to radio transients in general, including pulsars and Rotating Radio. Transients, we discuss the discovery of FRBs. We then discuss FRB follow-up observations in the ...

  7. MARS PATHFINDER RADIO TRACKING

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mars Pathfinder (MPF) Radio Science (RS) data archive contains both raw radio tracking data collected during the surface lifetime of the MPF Lander and results...

  8. A Likely Redback Millisecond Pulsar Counterpart of 3FGL J0838.8-2829

    Science.gov (United States)

    Halpern, J. P.; Strader, J.; Li, M.

    2017-08-01

    We obtained new optical observations of the X-ray source XMMU J083850.38-282756.8, the previously proposed counterpart of the γ-ray source 3FGL J0838.8-2829. Time-series photometry in the r\\prime band reveals periodic modulation of ≈ 1 mag that is characteristic of the heating of the photosphere of a low-mass companion star by a compact object. The measured orbital period is 5.14817 ± 0.00012 hr. The shape of the light curve is variable, evidently due to the effects of flaring and asymmetric heating. Spectroscopy reveals a companion of type M1 or later, having a radial velocity amplitude of 315 ± 17 km s-1, with period and phasing consistent with the heating interpretation. The mass function of the compact object is 0.69+/- 0.11 {M}⊙ , which allows a neutron star in a high-inclination orbit. Variable, broad Hα emission is seen, which is probably associated with a wind from the companion. These properties, as well as the X-ray and γ-ray luminosities at the inferred distance of millisecond pulsar in its non-accreting state. A search for radio pulsations is needed to confirm this interpretation and derive complete system parameters for modeling, although absorption by the ionized wind could hinder such detection.

  9. Silicon-based counterpart of alpha-graphyne

    Energy Technology Data Exchange (ETDEWEB)

    Aktürk, E., E-mail: ethem.akturk@adu.edu.tr [Department of Physics, Adnan Menderes University, Aydin 09100 (Turkey); Gökoğlu, G., E-mail: ggokoglu@karabuk.edu.tr [Department of Physics, Karabük University, 78050 Karabük (Turkey)

    2014-03-01

    We present the first principles density functional calculations of electronic structure and energetics of silicon-based counterpart of α-graphyne, labeled as α-silicyne. Both LDA and GGA functionals are applied for exchange–correlation potentials. We show that graphyne-like silicon in 2D buckled structure (equilibrium buckling δz≅0.73 and Δz≅1.45Å) has ≈2.33eV and ≈1.96eV lower energies than planar geometry for GGA and LDA functionals, respectively. The single and triple bond lengths of silicon are consistent with previously reported values. As a different case from graphyne, which is semimetallic, the electronic band structures of buckled α-silicyne do not show Dirac fermion indicating a metallic nature. The metallic character of the system is largely determined by p-electronic states of the triple bonded silicon atoms.

  10. Ham radio for dummies

    CERN Document Server

    Silver, H Ward

    2013-01-01

    An ideal first step for learning about ham radio Beyond operating wirelessly, today's ham radio operators can transmit data and pictures; use the Internet, laser, and microwave transmitters; and travel to places high and low to make contact. This hands-on beginner guide reflects the operational and technical changes to amateur radio over the past decade and provides you with updated licensing requirements and information, changes in digital communication (such as the Internet, social media, and GPS), and how to use e-mail via radio. Addresses the critical use of ham radio for replacing downe

  11. Simultaneous Monitoring of X-Ray and Radio Variability in Sagittarius A*

    Science.gov (United States)

    Capellupo, Daniel M.; Haggard, Daryl; Choux, Nicolas; Baganoff, Fred; Bower, Geoffrey C.; Cotton, Bill; Degenaar, Nathalie; Dexter, Jason; Falcke, Heino; Fragile, P. Chris; Heinke, Craig O.; Law, Casey J.; Markoff, Sera; Neilsen, Joey; Ponti, Gabriele; Rea, Nanda; Yusef-Zadeh, Farhad

    2017-08-01

    Monitoring of Sagittarius A* from X-ray to radio wavelengths has revealed structured variability—including X-ray flares—but it is challenging to establish correlations between them. Most studies have focused on variability in the X-ray and infrared, where variations are often simultaneous, and because long time series at submillimeter and radio wavelengths are limited. Previous work on submillimeter and radio variability hints at a lag between X-ray flares and their candidate submillimeter or radio counterparts, with the long wavelength data lagging the X-ray. However, there is only one published time lag between an X-ray flare and a possible radio counterpart. Here we report nine contemporaneous X-ray and radio observations of Sgr A*. We detect significant radio variability peaking ≳ 176 minutes after the brightest X-ray flare ever detected from Sgr A*. We also report other potentially associated X-ray and radio variability, with the radio peaks appearing ≲ 80 minutes after these weaker X-ray flares. Taken at face value, these results suggest that stronger X-ray flares lead to longer time lags in the radio. However, we also test the possibility that the variability at X-ray and radio wavelengths is not temporally correlated. We cross-correlate data from mismatched X-ray and radio epochs and obtain comparable correlations to the matched data. Hence, we find no overall statistical evidence that X-ray flares and radio variability are correlated, underscoring a need for more simultaneous, long duration X-ray-radio monitoring of Sgr A*.

  12. Radiography of Spanish Radio

    Directory of Open Access Journals (Sweden)

    Dra. Emma Rodero Antón

    2007-01-01

    Full Text Available In its eighty years of existence, radio has been always characterized to adapt to the social, cultural and technological transformations. Thus it has been until this moment. Nevertheless, some years ago, the authors and professionals of this medium have been detecting a stagnation that affects to its structure. At a time in continuous technological evolution, radio demands a deep transformation. For that reason, from the conviction of which the future radio, public and commercial, will necessarily have to renew itself, in this paper we establish ten problems and their possible solutions to the radio crisis in order to draw an x-ray of radio in Spain. Radio has future, but it is necessary to work actively by it. That the radio continues being part of sound of our life, it will depend on the work of all: companies, advertisers, professionals, students, investigators and listeners.

  13. Fermi GBM Counterparts to LIGO Gravitational-Wave Candidates

    Science.gov (United States)

    Racusin, Judith; Blackburn, Lindy; Briggs, Michael; Burns, Eric; Camp, Jordan; Canton, Tito Dal; Christensen, Nelson; Connaughton, Valerie; Goldstein, Adam; Jenke, Peter; Littenberg, Tyson; Shawhan, Peter; Singer, Leo; Veitch, John; Wilson-Hodge, Colleen; Zhang, Binbin

    2016-03-01

    As advanced LIGO begins operations, we eagerly anticipate the detection of gravitational waves (GW) in coincidence with a gamma-ray signal from the Fermi Gamma-ray Burst Monitor (GBM). The most likely source is a short Gamma-Ray Burst (GRB) arising from the merger of two neutron stars. With its broad sky coverage, GBM triggers and localizes more short GRBs than other active space missions, 45 each year, with an estimate of <1-5 within the LIGO detection horizon. Combining GBM and LIGO localization uncertainty regions may provide a smaller region for GW host searches. A joint GBM-LIGO detection increases the confidence in the GW detection and helps characterize the parameters of the merger. Offline searches for weak GRBs that fail to trigger onboard Fermi indicate that additional short GRBs can be detected in the GBM data. I will discuss joint searches to detect and localize GW candidates, and explore how the non-detection in the GBM data of a signal consistent with GW candidates in the LIGO data can affect follow-up strategies for counterpart searches by other observers.

  14. Exactly solvable PT-symmetric Hamiltonian having no Hermitian counterpart

    Science.gov (United States)

    Bender, Carl M.; Mannheim, Philip D.

    2008-07-01

    In a recent paper Bender and Mannheim showed that the unequal-frequency fourth-order derivative Pais-Uhlenbeck oscillator model has a realization in which the energy eigenvalues are real and bounded below, the Hilbert-space inner product is positive definite, and time evolution is unitary. Central to that analysis was the recognition that the Hamiltonian HPU of the model is PT symmetric. This Hamiltonian was mapped to a conventional Dirac-Hermitian Hamiltonian via a similarity transformation whose form was found exactly. The present paper explores the equal-frequency limit of the same model. It is shown that in this limit the similarity transform that was used for the unequal-frequency case becomes singular and that HPU becomes a Jordan-block operator, which is nondiagonalizable and has fewer energy eigenstates than eigenvalues. Such a Hamiltonian has no Hermitian counterpart. Thus, the equal-frequency PT theory emerges as a distinct realization of quantum mechanics. The quantum mechanics associated with this Jordan-block Hamiltonian can be treated exactly. It is shown that the Hilbert space is complete with a set of nonstationary solutions to the Schrödinger equation replacing the missing stationary ones. These nonstationary states are needed to establish that the Jordan-block Hamiltonian of the equal-frequency Pais-Uhlenbeck model generates unitary time evolution.

  15. Fermi GBM Counterparts to LIGO Gravitational-Wave Candidates

    Science.gov (United States)

    Burns, Eric; Blackburn, Lindy; Briggs, Michael Stephen; Camp, Jordan; Christensen, Nelson; Connaughton, Valerie; Goldstein, Adam; Littenberg, Tyson; Racusin, Judith L.; Shawhan, Peter S.; Pound Singer, Leo; Veitch, John; Zhang, Binbin

    2016-04-01

    As the advanced configuration of the Laser Interferometer Gravitational-wave Observatory has begun operations, we eagerly anticipate the detection of gravitational waves (GW) with LIGO in coincidence with a gamma-ray signal from the Fermi Gamma-ray Burst Monitor (GBM). The most likely source is a short Gamma-Ray Burst (GRB) arising from the merger of two compact objects. With its broad sky coverage, GBM triggers and localizes more short GRBs than other active space missions, ~40 each year. Combining GBM and LIGO localization uncertainty regions may provide a smaller target to look for the GW host. A joint GBM-LIGO detection increases the confidence in the GW detection and helps characterize the parameters of the merger. Offline searches for weak GRBs that fail to trigger onboard Fermi indicate that additional short GRBs can be detected in the GBM data. I will discuss the implementation and expected benefits of joint searches to detect and localize GW candidates. I will also explore how the non-detection in the GBM data of a signal consistent with GW candidates in the LIGO data can affect follow-up strategies for counterpart searches by other observers.

  16. Gamma Ray Burst Optical Counterpart Search Experiment (GROCSE)

    Science.gov (United States)

    Park, H. S.; Ables, E.; Bionta, R. M.; Ott, L.; Parker, E.; Akerlof, C.; Lee, B.; Wallace, S.; Barthelmy, S.; Butterworth, P.

    1995-01-01

    GROCSE (Gamma-Ray Optical Counterpart Search Experiments) is a system of automated telescopes that search for simultaneous optical activity associated with gamma ray bursts in response to real-time burst notifications provided by the BATSE/BACODINE network. The first generation system, GROCSE 1, is sensitive down to Mv (approximately) 8.5 and requires an average of 12 seconds to obtain the first images of the gamma ray burst error box defined by the BACODINE trigger. The collaboration is now constructing a second generation system which has a 4 second slewing time and can reach Mv (approximately) 14 with a 5 second exposure. GROCSE 2 consists of 4 cameras on a single mount. Each camera views the night sky through a commercial Canon lens (f/1.8, focal length 200 mm) and utilizes a 2K x 2K Loral CCD. Light weight and low noise custom readout electronics were designed and fabricated for these CCDs. The total field of view of the 4 cameras is 17.6 x 17.6 (degree). GROCSE 2 will be operated by the end of 1995. In this paper, the authors present an overview of the GROCSE system and the results of measurements with a GROCSE 2 prototype unit.

  17. ELECTROMAGNETIC COUNTERPARTS TO BLACK HOLE MERGERS DETECTED BY LIGO

    Energy Technology Data Exchange (ETDEWEB)

    Loeb, Abraham, E-mail: aloeb@cfa.harvard.edu [Department of Astronomy, Harvard University, 60 Garden St., Cambridge, MA 02138 (United States)

    2016-03-10

    Mergers of stellar-mass black holes (BHs), such as GW150914 observed by Laser Interferometer Gravitational Wave Observatory (LIGO), are not expected to have electromagnetic counterparts. However, the Fermi GBM detector identified a γ-ray transient 0.4 s after the gravitational wave (GW) signal GW150914 with consistent sky localization. I show that the two signals might be related if the BH binary detected by LIGO originated from two clumps in a dumbbell configuration that formed when the core of a rapidly rotating massive star collapsed. In that case, the BH binary merger was followed by a γ-ray burst (GRB) from a jet that originated in the accretion flow around the remnant BH. A future detection of a GRB afterglow could be used to determine the redshift and precise localization of the source. A population of standard GW sirens with GRB redshifts would provide a new approach for precise measurements of cosmological distances as a function of redshift.

  18. The radio structure of radio-quiet quasars

    NARCIS (Netherlands)

    Leipski, C.; Falcke, H.D.E.; Bennert, N.; Hüttemeister, S.

    2006-01-01

    Aims.We investigate the radio emitting structures of radio-quiet active galactic nuclei with an emphasis on radio-quiet quasars to study their connection to Seyfert galaxies.
    Methods: .We present and analyse high-sensitivity VLA radio continuum images of 14 radio-quiet quasars and six Seyfert

  19. Senior radio listeners

    DEFF Research Database (Denmark)

    Blaakilde, Anne Leonora

    media platforms, not the least when listening to radio. The elder generation is no exception from this. Recently, for instance, the Danish public broadcast DR has carried out an exodus of programmes targeted for the senior segment. These programmes are removed from regular FM and sent to DAB receivers......Radiobroadcasting and the hardware materialization of radio have during the 20th century changed significantly, which means that senior radio listeners have travelled along with this evolution from large, impressive radio furnitures to DAB and small, wireless, mobile devices, and from grave...... and solemn radio voices to lightharted, laughing and chatting speakers. Senior radio listerners have experienced the development and refinements of technique, content and genres. It is now expected of all media users that they are capable of crossing media, combining, juggling and jumping between various...

  20. A burst in a wind bubble and the impact on baryonic ejecta: high-energy gamma-ray flashes and afterglows from fast radio bursts and pulsar-driven supernova remnants

    Science.gov (United States)

    Murase, Kohta; Kashiyama, Kazumi; Mészáros, Peter

    2016-09-01

    Tenuous wind bubbles, which are formed by the spin-down activity of central compact remnants, are relevant in some models of fast radio bursts (FRBs) and superluminous supernovae (SNe). We study their high-energy signatures, focusing on the role of pair-enriched bubbles produced by young magnetars, rapidly rotating neutron stars, and magnetized white dwarfs. (i) First, we study the nebular properties and the conditions allowing for escape of high-energy gamma-rays and radio waves, showing that their escape is possible for nebulae with ages of ≳10-100 yr. In the rapidly rotating neutron star scenario, we find that radio emission from the quasi-steady nebula itself may be bright enough to be detected especially at sub-mm frequencies, which is relevant as a possible counterpart of pulsar-driven SNe and FRBs. (ii) Secondly, we consider the fate of bursting emission in the nebulae. We suggest that an impulsive burst may lead to a highly relativistic flow, which would interact with the nebula. If the shocked nebula is still relativistic, pre-existing non-thermal particles in the nebula can be significantly boosted by the forward shock, leading to short-duration (maybe millisecond or longer) high-energy gamma-ray flashes. Possible dissipation at the reverse shock may also lead to gamma-ray emission. (iii) After such flares, interactions with the baryonic ejecta may lead to afterglow emission with a duration of days to weeks. In the magnetar scenario, this burst-in-bubble model leads to the expectation that nearby (≲10-100 Mpc) high-energy gamma-ray flashes may be detected by the High-Altitude Water Cherenkov Observatory and the Cherenkov Telescope Array, and the subsequent afterglow emission may be seen by radio telescopes such as the Very Large Array. (iv) Finally, we discuss several implications specific to FRBs, including constraints on the emission regions and limits on soft gamma-ray counterparts.

  1. Morphology and astrometry of Infrared-Faint Radio Sources

    Science.gov (United States)

    Middelberg, Enno; Norris, Ray; Randall, Kate; Mao, Minnie; Hales, Christopher

    2008-10-01

    Infrared-Faint Radio Sources, or IFRS, are an unexpected class of object discovered in the Australia Telescope Large Area Survey, ATLAS. They are compact 1.4GHz radio sources with no visible counterparts in co-located (relatively shallow) Spitzer infrared and optical images. We have detected two of these objects with VLBI, indicating the presence of an AGN. These observations and our ATLAS data indicate that IFRS are extended on scales of arcseconds, and we wish to image their morphologies to obtain clues about their nature. These observations will also help us to select optical counterparts from very deep, and hence crowded, optical images which we have proposed. With these data in hand, we will be able to compare IFRS to known object types and to apply for spectroscopy to obtain their redshifts.

  2. An AGN or a Be star as possible counterparts of 3FGL J0133.3+5930

    Science.gov (United States)

    Martí, J.; Luque-Escamilla, P. L.; Paredes, J. M.; Iwasawa, K.; Galindo, D.; Ribó, M.; Marín-Felip, V.

    2017-03-01

    We present recent results from our program for cross-identification of unassociated gamma-ray sources at low galactic latitudes. The main motivation for this work is the search for new members of the scarce class of gamma-ray binaries and microquasars. Here we report the case of the Fermi LAT source 3FGL J0133.3+5930. Two peculiar objects have been found inside the 95% confidence contour of this unassociated gamma-ray source. One of them is the optically bright Be star TYC 3683-985-1, also consistent with the ROSAT X-ray source 1RXS J013326.9+592946. In this work, we have discovered it to be a new eclipsing binary system. The other is the Swift X-ray source SWIFT J0132.9+ 5932 whose radio, infrared and optical counterpart are still under study. Based on the observational evidence available, SWIFT J0132.9+5932 stands as the most likely counterpart to 3FGL J0133.3+5930. Although its spectral energy distribution appears to be consistent with a stellar system, a possible Active Galactic Nuclei nature cannot be yet ruled out.

  3. An Enhanced Method for Scheduling Observations of Large Sky Error Regions for Finding Optical Counterparts to Transients

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Javed; Singhal, Akshat; Gadre, Bhooshan; Bhalerao, Varun; Bose, Sukanta, E-mail: javed@iucaa.in [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007 (India)

    2017-04-01

    The discovery and subsequent study of optical counterparts to transient sources is crucial for their complete astrophysical understanding. Various gamma-ray burst (GRB) detectors, and more notably the ground-based gravitational wave detectors, typically have large uncertainties in the sky positions of detected sources. Searching these large sky regions spanning hundreds of square degrees is a formidable challenge for most ground-based optical telescopes, which can usually image less than tens of square degrees of the sky in a single night. We present algorithms for better scheduling of such follow-up observations in order to maximize the probability of imaging the optical counterpart, based on the all-sky probability distribution of the source position. We incorporate realistic observing constraints such as the diurnal cycle, telescope pointing limitations, available observing time, and the rising/setting of the target at the observatory’s location. We use simulations to demonstrate that our proposed algorithms outperform the default greedy observing schedule used by many observatories. Our algorithms are applicable for follow-up of other transient sources with large positional uncertainties, such as Fermi -detected GRBs, and can easily be adapted for scheduling radio or space-based X-ray follow-up.

  4. STEM on the radio

    Science.gov (United States)

    Showstack, Randy

    2011-10-01

    Looking for an Internet radio station focusing on programing about science, technology, engineering, and math (STEM)? The U.S. National Science Foundation (NSF) announced on 26 September the launch of Science360 Radio, which it says is the first Internet radio stream dedicated to STEM programing. Science360 includes more than 100 radio shows and podcasts that are available on the Web as well as on iPhone and Android devices. The shows originate from a variety of sources, including NSF, other U.S. government agencies, science organizations, universities, and media outlets. For more information, see http://science360.gov/files/.

  5. A Zynq-based Cluster Cognitive Radio

    OpenAIRE

    Rooks, Kurtis M.

    2014-01-01

    Traditional hardware radios provide very rigid solutions to radio problems. Intelligent software defined radios, also known as cognitive radios, provide flexibility and agility compared to hardware radio systems. Cognitive radios are well suited for radio applications in a changing radio frequency environment, such as dynamic spectrum access. In this thesis, a cognitive radio is demonstrated where the system self reconfigures to dem...

  6. Decameter Type III-Like Bursts

    Science.gov (United States)

    Melnik, V. N.; Konovalenko, A. A.; Rutkevych, B. P.; Rucker, H. O.; Dorovskyy, V. V.; Abranin, E. P.; Lecacheux, A.; Brazhenko, A. I.; Stanislavskyy, A. A.

    2007-12-01

    Starting from 1960s Type III-like bursts (Type III bursts with high drift rates) in a wide frequency range from 300 to 950MHz have been observed. These new bursts observed at certain frequency being compared to the usual Type III bursts at the same frequency show similar behaviour but feature frequency drift 2-6 times higher than the normal bursts. In this paper we report the first observations of Type III-like bursts in decameter range, carried out during summer campaigns 2002 - 2004 at UTR-2 radio telescope. The circular polarization of the bursts was measured by the radio telescope URAN-2 in 2004. The observed bursts are analyzed and compared with usual Type III bursts in the decameter range. From the analysis of over 1100 Type III-like bursts, their main parameters have been found. Characteristic feature of the observed bursts is similar to Type III-like bursts at other frequencies, i.e. measured drift rates (5-10 MHz/s) of this bursts are few times larger than that for usual Type III bursts, and their durations (1-2 s) are few times smaller than that for usual Type III bursts in this frequency band.

  7. Radio-Astronomical Instruments Observations (Selected Articles),

    Science.gov (United States)

    1982-08-02

    etc. merged into this translation were extracted from the best quality copy available. iii DOC = 82056401 PAGE 1 RADIO-ASTRONOMICAL INSTRUMENTS...itself the series/row of the positive qualities : the possibility of tracking the observed object and the accumulation of signal, the possibility of...L-intoduc ;j~i.a~r DC 82056409 PAGE the installation of quasi-zero mode/conditions this attenuator has remote contril . I’ DOC =82056409 PAGE NA 4 ly

  8. VizieR Online Data Catalog: S2CLS: multiwavelength counterparts to SMGs (Chen+, 2016)

    Science.gov (United States)

    Chen, C.-C.; Smail, I.; Ivison, R. J.; Arumugam, V.; Almaini, O.; Conselice, C. J.; Geach, J. E.; Hartley, W. G.; Ma, C.-J.; Mortlock, A.; Simpson, C.; Simpson, J. M.; Swinbank, A. M.; Aretxaga, I.; Blain, A.; Chapman, S. C.; Dunlop, J. S.; Farrah, D.; Halpern, M.; Michalowski, M. J.; van der Werf, P.; Wilkinson, A.; Zavala, J. A.

    2016-05-01

    The SCUBA-2 data at 850um in the UDS field were taken as part of the SCUBA-2 Cosmology Legacy Survey (S2CLS). The full data reduction steps are described fully in J. E. Geach et al. (2016, in preparation). In total we detect 1088 submillimeter sources at >=3.5σ within the region where rms noise is =4.0σ, for which we expect a false detection rate of ~1% based on simulations and source extractions on negative signals. We also define a supplementary sample of 372 submillimeter sources that are detected at 3.5-4.0σ and have a false detection rate of ~10%. In this paper, we provide counterpart candidates for both main and supplementary samples; however, the scientific analyses were performed on the main sample. We have carried out ALMA follow-up observations at 870um on 30 of the brighter SCUBA-2 sources in a Cycle 1 project 2012.1.00090.S (Simpson et al. 2015ApJ...807..128S, 2015ApJ...799...81S). The K-band-based multiwavelength photometry adopted in this paper is based on the UDS data release 8 (DR8) of the UKIRT Infrared Deep Sky Survey (UKIDSS; Lawrence et al. 2007, see II/319). The VLA radio observations at 1.4GHz (20cm) were carried out by the project UDS20 (V. Arumugam et al. 2016, in preparation), which comprises a mosaic of 14 pointings covering a total area of ~1.3deg2 centered on the UDS. The ~1 square degree UDS field contains a rich set of ancillary data (see section 2 for further details). (2 data files).

  9. Low-Frequency Radio Bursts and Space Weather

    Science.gov (United States)

    Gopalswamy, N.

    2016-01-01

    Low-frequency radio phenomena are due to the presence of nonthermal electrons in the interplanetary (IP) medium. Understanding these phenomena is important in characterizing the space environment near Earth and other destinations in the solar system. Substantial progress has been made in the past two decades, because of the continuous and uniform data sets available from space-based radio and white-light instrumentation. This paper highlights some recent results obtained on IP radio phenomena. In particular, the source of type IV radio bursts, the behavior of type III storms, shock propagation in the IP medium, and the solar-cycle variation of type II radio bursts are considered. All these phenomena are closely related to solar eruptions and active region evolution. The results presented were obtained by combining data from the Wind and SOHO missions.

  10. Boom Booom Net Radio

    DEFF Research Database (Denmark)

    Grimshaw, Mark Nicholas; Yong, Louisa; Dobie, Ian

    1999-01-01

    of an existing Internet radio station; Boom Booom Net Radio. Whilst necessity dictates some use of technology-related terminology, wherever possible we have endeavoured to keep such jargon to a minimum and to either explain it in the text or to provide further explanation in the appended glossary....

  11. The LOFAR radio environment

    NARCIS (Netherlands)

    Offringa, A. R.; de Bruyn, A. G.; Zaroubi, S.; van Diepen, G.; Martinez-Ruby, O.; Labropoulos, P.; Brentjens, M. A.; Ciardi, B.; Daiboo, S.; Harker, G.; Jelic, V.; Kazemi, S.; Koopmans, L. V. E.; Pandey, V. N.; Pizzo, R. F.; Schaye, J.; Vedantham, H.; Veligatla, V.; Wijnholds, S. J.; Yatawatta, S.; Zarka, P.; Alexov, A.; Anderson, J.; Asgekar, A.; Avruch, M.; Beck, R.; Bell, M.; Bell, M. R.; Bentum, M.; Bernardi, G.; Best, P.; Birzan, L.; Bonafede, A.; Breitling, F.; Broderick, J. W.; Brueggen, M.; Butcher, H.; Conway, J.; de Vos, M.; Dettmar, R. J.; Eisloeffel, J.; Falcke, H.; Fender, R.; Frieswijk, W.; Gerbers, M.; Griessmeier, J. M.; Gunst, A. W.; Hassall, T. E.; Heald, G.; Hessels, J.; Hoeft, M.; Horneffer, A.; Karastergiou, A.; Kondratiev, V.; Koopman, Y.; Kuniyoshi, M.; Kuper, G.; Maat, P.; Mann, G.; McKean, J.; Meulman, H.; Mevius, M.; Mol, J.D.; Nijboer, R.; Noordam, J.; Norden, M.; Paas, H.; Pandey, M.; Pizzo, R.; Polatidis, A.; Rafferty, D.; Rawlings, S.; Reich, W.; Roettgering, H. J. A.; Schoenmakers, A. P.; Sluman, J.; Smirnov, O.; Sobey, C.; Stappers, B.; Steinmetz, M.; Swinbank, J.; Tagger, M.; Tang, Y.; Tasse, C.; van Ardenne, A.; van Cappellen, W.; van Duin, A. P.; van Haarlem, M.; van Leeuwen, J.; van Weeren, R. J.; Vermeulen, R.; Vocks, C.; Wijers, R. A. M. J.; Wise, M.; Wucknitz, O.; Mellema, G.

    Aims. This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods. We have analysed the radio-frequency interference (RFI) situation in two 24-h surveys with Dutch LOFAR stations, covering 30-78 MHz

  12. Radio Graceful Hamming Graphs

    Directory of Open Access Journals (Sweden)

    Niedzialomski Amanda

    2016-11-01

    Full Text Available For k ∈ ℤ+ and G a simple, connected graph, a k-radio labeling f : V (G → ℤ+ of G requires all pairs of distinct vertices u and v to satisfy |f(u − f(v| ≥ k + 1 − d(u, v. We consider k-radio labelings of G when k = diam(G. In this setting, f is injective; if f is also surjective onto {1, 2, . . . , |V (G|}, then f is a consecutive radio labeling. Graphs that can be labeled with such a labeling are called radio graceful. In this paper, we give two results on the existence of radio graceful Hamming graphs. The main result shows that the Cartesian product of t copies of a complete graph is radio graceful for certain t. Graphs of this form provide infinitely many examples of radio graceful graphs of arbitrary diameter. We also show that these graphs are not radio graceful for large t.

  13. Writing for Radio.

    Science.gov (United States)

    Tupper, Marianna S.

    1995-01-01

    Describes a 24-hour commercial radio station simulation class project for eighth-grade language arts. Students wrote their own scripts, chose music and were disc jockeys on their own music and talk shows, and prepared news and traffic reports. Guest speakers from actual commercial radio came in to discuss issues such as advertising, censorship,…

  14. Uranus radio emissions

    Science.gov (United States)

    Kaiser, Michael L.

    An overview of the Voyager 2 Planetary Radio Astronomy instrument observations of the planet Uranus is presented. From these observations, a number of inferences have been made including the rotation period of the interior of the planet and the source locations of several of the radio components.

  15. Radio Surveys: an Overview

    NARCIS (Netherlands)

    Morganti, Raffaella

    Radio astronomy has provided important surveys that have made possible key (and sometimes serendipitous) discoveries. I will briefly mention some of the past continuum and line (HI) radio surveys as well as new, on-going surveys and surveys planned for the near future. This new generation of large

  16. Ionosphere and Radio Communication

    Indian Academy of Sciences (India)

    The upperionosphere is used for radio communication and navigationas it reflects long, medium, as well as short radio waves. Sincesolar radiation is the main cause of the existence of ionosphere,any variation in the radiations can affect the entireradio communication system. This article attempts to brieflyintroduce the ...

  17. Valuing commercial radio licences

    NARCIS (Netherlands)

    Kerste, M.; Poort, J.; van Eijk, N.

    2015-01-01

    Within the EU regulatory framework, licensees for commercial radio broadcasting may be charged a fee to ensure optimal allocation of scarce resources but not to maximize public revenues. While radio licence renewal occurs in many EU countries, an objective, model-based approach for setting licence

  18. A joint model of pulsar radio and gamma ray emission

    Science.gov (United States)

    Qiao, G.

    The radiation of radio pulsars have been observed from radio to gamma -rays for many years. Observations present abundance infor-mation. Theoretical models for radio and gamma-rays are presented separately. Until now we do not found a model can show emission from radio to gamma -rays at the same time detailedly. For a certain pul-sar, the emission from radio to gamma-rays can be observed at the same time (such as Crab pulsar and so on). So a reasonable model should present the emission from radio to gamma - rays at the same time more detailedly. A joint model for emission from radio to gamma -rays is presented in this paper. Which can show emission characters for both radio and gamma -ray emission band. Such as core and cone emis -s i o n beams at radio emission band, and gamma - rays for Geminga-like, Crab-like and Vela - like emission beams can be shown at the same time. First of all, an inverse Compton scattering model(ICS model, partly see ICS I A &A 1998; ICS II A &A 2001; ICS III ApJ 2000) of radio pulsars will be introduced more detailedly. Then a new model for gamma - ray emission will be introduced. In this model both radio and gamma-ray emission mechanisms are jointed, and the emission beams from radio to gamma -rays can be presented. Various kind of pulse profiles and other observational characteristics can be shown and the theory in agreement with observations well.

  19. RADIO REFRACTIVITY RADIO REFRACTIVITY STUDY IN AKURE ...

    African Journals Online (AJOL)

    eobe

    The basic parameters that describe the troposphere region are pressure, temperature and relative humidity. Variations in these conditions within the troposphere cause changes in the refractive index of air and large scale changes of refractive index with height cause radio waves to be refracted and the effect can be quite.

  20. Quark nova model for fast radio bursts

    Science.gov (United States)

    Shand, Zachary; Ouyed, Amir; Koning, Nico; Ouyed, Rachid

    2016-05-01

    Fast radio bursts (FRBs) are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star's light cylinder via β-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm-3 pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of β-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies (˜ 1041 erg) and spectral shapes, and provide a theoretical framework for determining distances.

  1. Richard III

    DEFF Research Database (Denmark)

    Lauridsen, Palle Schantz

    2017-01-01

    Kort analyse af Shakespeares Richard III med fokus på, hvordan denne skurk fremstilles, så tilskuere (og læsere) langt henad vejen kan føle sympati med ham. Med paralleller til Netflix-serien "House of Cards"......Kort analyse af Shakespeares Richard III med fokus på, hvordan denne skurk fremstilles, så tilskuere (og læsere) langt henad vejen kan føle sympati med ham. Med paralleller til Netflix-serien "House of Cards"...

  2. THE DISCOVERY OF A YOUNG RADIO GALAXY AT Z = 2.390 - PROBING INITIAL STAR FORMATION AT Z-LESS-THAN-APPROXIMATELY-EQUAL-TO-3.0

    NARCIS (Netherlands)

    WINDHORST, RA; BURSTEIN, D; MATHIS, DF; NEUSCHAEFER, LW; BERTOLA, F; BUSON, LM; KOO, DC; MATTHEWS, K; BARTHEL, PD; CHAMBERS, KC

    1991-01-01

    We present the discovery of a weak radio galaxy from the Leiden Berkeley Deep Survey at a redshift of 2.390, the faint optical and IR counterpart of the steep-spectrum, compact radio source 53W002. Its lambda-dependent optical continuum morphology is compact with linear size approximately 10-35 kpc

  3. Radio broadcasting via satellite

    Science.gov (United States)

    Helm, Neil R.; Pritchard, Wilbur L.

    1990-10-01

    Market areas offering potential for future narrowband broadcast satellites are examined, including international public diplomacy, government- and advertising-supported, and business-application usages. Technical issues such as frequency allocation, spacecraft types, transmission parameters, and radio receiver characteristics are outlined. Service and system requirements, advertising revenue, and business communications services are among the economic issues discussed. The institutional framework required to provide an operational radio broadcast service is studied, and new initiatives in direct broadcast audio radio systems, encompassing studies, tests, in-orbit demonstrations of, and proposals for national and international commercial broadcast services are considered.

  4. Unlocking radio broadcasts

    DEFF Research Database (Denmark)

    Lykke, Marianne; Skov, Mette

    2012-01-01

    This poster reports the preliminary results of a user study uncovering the information seeking behaviour of humanities scholars dedicated to radio research. The study is part of an interdisciplinary research project on radio culture and auditory resources. The purpose of the study is to inform...... the design of information architecture and interaction design of a research infrastructure that will enable future radio and audio based research. Results from a questionnaire survey on humanities scholars’ research interest and information needs, preferred access points, and indexing levels are reported...

  5. Shoestring Budget Radio Astronomy

    Science.gov (United States)

    Hoot, John E.

    2017-06-01

    The commercial exploitation of microwave frequencies for cellular, WiFi, Bluetooth, HDTV, and satellite digital media transmission has brought down the cost of the components required to build an effective radio telescope to the point where, for the cost of a good eyepiece, you can construct and operate a radio telescope. This paper sets forth a family of designs for 1421 MHz telescopes. It also proposes a method by which operators of such instruments can aggregate and archive data via the Internet. With 90 or so instruments it will be possible to survey the entire radio sky for transients with a 24 hour cadence.

  6. Finding counterparts for all-sky X-ray surveys with NWAY: a Bayesian algorithm for cross-matching multiple catalogues

    Science.gov (United States)

    Salvato, M.; Buchner, J.; Budavári, T.; Dwelly, T.; Merloni, A.; Brusa, M.; Rau, A.; Fotopoulou, S.; Nandra, K.

    2018-02-01

    We release the AllWISE counterparts and Gaia matches to 106 573 and 17 665 X-ray sources detected in the ROSAT 2RXS and XMMSL2 surveys with |b| > 15°. These are the brightest X-ray sources in the sky, but their position uncertainties and the sparse multi-wavelength coverage until now rendered the identification of their counterparts a demanding task with uncertain results. New all-sky multi-wavelength surveys of sufficient depth, like AllWISE and Gaia, and a new Bayesian statistics based algorithm, NWAY, allow us, for the first time, to provide reliable counterpart associations. NWAY extends previous distance and sky density based association methods and, using one or more priors (e.g. colours, magnitudes), weights the probability that sources from two or more catalogues are simultaneously associated on the basis of their observable characteristics. Here, counterparts have been determined using a Wide-field Infrared Survey Explorer (WISE) colour-magnitude prior. A reference sample of 4524 XMM/Chandra and Swift X-ray sources demonstrates a reliability of ∼94.7 per cent (2RXS) and 97.4 per cent (XMMSL2). Combining our results with Chandra-COSMOS data, we propose a new separation between stars and AGN in the X-ray/WISE flux-magnitude plane, valid over six orders of magnitude. We also release the NWAY code and its user manual. NWAY was extensively tested with XMM-COSMOS data. Using two different sets of priors, we find an agreement of 96 per cent and 99 per cent with published Likelihood Ratio methods. Our results were achieved faster and without any follow-up visual inspection. With the advent of deep and wide area surveys in X-rays (e.g. SRG/eROSITA, Athena/WFI) and radio (ASKAP/EMU, LOFAR, APERTIF, etc.) NWAY will provide a powerful and reliable counterpart identification tool.

  7. On the morphological dichotomies observed in the powerful radio galaxies

    Science.gov (United States)

    Miraghaei, H.; Best, P. N.

    2017-06-01

    We study environment and host galaxy properties of powerful radio galaxies with different radio morphologies from compact sources to very extended double lobed radio galaxies and with different optical spectra classified as high excitation (HERG; quasar-mode) and low excitation (LERG; jet-mode) radio galaxies. We use a complete sample of morphologically classified radio sources from [1] and perform three different analyses: i) we compare compact radio sources with the extended sources from the same class of excitation. ii) we compare HERGs with the LERGs using a combined sample of compact and extended sources. iii) we investigate the origin of different morphologies observed in the very extended powerful radio galaxies, historically classified as Fanaroff-Riley (FR) radio galaxies of type I and type II by comparing a sample of FRIs with the FRIIs from the same excitation class. We discuss the results and what causes the differences in each comparison. The role of host galaxy and the central super massive black hole, and the galaxy interactions are all investigated.

  8. Building a Dynamic Spectrum Access Smart Radio with Application to Public Safety Disaster Communications

    Science.gov (United States)

    2009-08-13

    34 IEEE Personal Communications, vol. 6, pp. 13-18, 1999. [18] J. Mitola, III, "Cognitive Radio for Flexible Mobile Multimedia Communications," in... IEEE International Workshop on Mobile Multimedia Communications (MoMuC), San Diego, CA, 1999, pp. 3-10. [19] S. Haykin, "Cognitive Radio: Brain...general purpose processors (GPP) and field-programmable gate arrays ( FPGA ) have been cost prohibitive for use in inexpensive hand-held radio systems

  9. Properties and environment of radio-emitting galaxies in the VLA-zCOSMOS survey

    NARCIS (Netherlands)

    Bardelli, S.; Schinnerer, E.; Smolčic, V.; Zamorani, G.; Zucca, E.; Mignoli, M.; Halliday, C.; Kovač, K.; Ciliegi, P.; Caputi, K.; Koekemoer, A. M.; Bongiorno, A.; Bondi, M.; Bolzonella, M.; Vergani, D.; Pozzetti, L.; Carollo, C. M.; Contini, T.; Kneib, J.-P.; Le Fèvre, O.; Lilly, S.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Coppa, G.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Kampczyk, P.; Knobel, C.; Lamareille, F.; Le Borgne, J.-F.; Le Brun, V.; Maier, C.; Pellò, R.; Peng, Y.; Perez-Montero, E.; Ricciardelli, E.; Silverman, J. D.; Tanaka, M.; Tasca, L.; Tresse, L.; Abbas, U.; Bottini, D.; Cappi, A.; Cassata, P.; Cimatti, A.; Guzzo, L.; Leauthaud, A.; Maccagni, D.; Marinoni, C.; McCracken, H. J.; Memeo, P.; Meneux, B.; Oesch, P.; Porciani, C.; Scaramella, R.; Capak, P.; Sanders, D.; Scoville, N.; Taniguchi, Y.; Jahnke, K.

    Aims: We investigate the properties and the environment of radio sources with optical counterparts from the combined VLA-COSMOS and zCOSMOS samples. The advantage of this sample is the availability of optical spectroscopic informations, high quality redshifts, and accurate density determination.

  10. 47 CFR 80.1089 - Ship radio equipment-Sea areas A1 and A2.

    Science.gov (United States)

    2010-10-01

    ...; or (iii) Through the INMARSAT geostationary satellite service if within INMARSAT coverage; this... alerts by a radio service other than MF operating either: (i) Through the polar orbiting satellite...

  11. Music, radio and mediatization

    DEFF Research Database (Denmark)

    Michelsen, Morten; Krogh, Mads

    2016-01-01

    Mediatization has become a key concept for understanding the relations between media and other cultural and social fields. Contributing to the discussions related to the concept of mediatization, this article discusses how practices of radio and music(al life) influence each other. We follow Deacon......’s and Stanyer’s advice to supplement the concept of mediatization with ‘a series of additional concepts at lower levels of abstraction’ and suggest, in this respect, the notion of heterogeneous milieus of music–radio. Hereby, we turn away from the all-encompassing perspectives related to the concept...... of mediatization where media as such seem to be ascribed agency. Instead, we consider historical accounts of music–radio in order to address the complex nonlinearity of concrete processes of mediatization as they take place in the multiple meetings between a decentred notion of radio and musical life....

  12. The digital sport radio.

    Directory of Open Access Journals (Sweden)

    Hilario José ROMERO BEJARANO

    2014-07-01

    Full Text Available Radio has been immersed in recent years in a phase of technological integration and business of multimedia, as well as diversification of systems and channels for broadcasting. In addition, Internet has been consolidated as the platform of digital radio that more has evolved as a result of its continued expansion. However, the merger radio-Internet must be understood as a new form of communication, and not solely as a new complementary medium. In this context, it is of great interest to analyze that transformations in the way of reception, contents, languages, programs and schedules, has brought with it for the radio that integration. To this end is taken as main reference the sports areas, a key aspect and broadly representative of the current broadcasting landscape.

  13. Social cognitive radio networks

    CERN Document Server

    Chen, Xu

    2015-01-01

    This brief presents research results on social cognitive radio networks, a transformational and innovative networking paradigm that promotes the nexus between social interactions and cognitive radio networks. Along with a review of the research literature, the text examines the key motivation and challenges of social cognitive radio network design. Three socially inspired distributed spectrum sharing mechanisms are introduced: adaptive channel recommendation mechanism, imitation-based social spectrum sharing mechanism, and evolutionarily stable spectrum access mechanism. The brief concludes with a discussion of future research directions which ascertains that exploiting social interactions for distributed spectrum sharing will advance the state-of-the-art of cognitive radio network design, spur a new line of thinking for future wireless networks, and enable novel wireless service and applications.

  14. Eratosthenes via Ham Radio

    Science.gov (United States)

    Koser, John F.

    1975-01-01

    A secondary geology class used Eratosthenes' method for measuring the circumference of the earth by comparing their measurements of the shadow of a vertical rod to the measurements made by another person contacted by ham radio. (MLH)

  15. Everyday Radio Telescope

    CERN Document Server

    Mandal, Pranshu; Kumar, Pratik; Yelikar, Anjali; Soni, Kanchan; T, Vineeth Krishna

    2016-01-01

    We have developed an affordable, portable college level radio telescope for amateur radio astronomy which can be used to provide hands-on experience with the fundamentals of a radio telescope and an insight into the realm of radio astronomy. With our set-up one can measure brightness temperature and flux of the Sun at 11.2 GHz and calculate the beam width of the antenna. The set-up uses commercially available satellite television receiving system and parabolic dish antenna. We report the detection of point sources like Saturn and extended sources like the galactic arm of the Milky way. We have also developed python pipeline, which are available for free download, for data acquisition and visualization.

  16. Wireless radio a history

    CERN Document Server

    Coe, Lewis

    2006-01-01

    ""Informative...recommended""--Choice; ""interesting...a good read...well worth reading""--Contact Magazine. This history first looks at Marconi's wireless communications system and then explores its many applications, including marine radio, cellular telephones, police and military uses, television and radar. Radio collecting is also discussed, and brief biographies are provided for the major figures in the development and use of the wireless.

  17. Classics in radio astronomy

    CERN Document Server

    Sullivan, Woodruff Turner

    1982-01-01

    Radio techniques were the nrst to lead astronomy away from the quiescent and limited Universe revealed by traditional observations at optical wave­ lengths. In the earliest days of radio astronomy, a handful of radio physicists and engineers made one startling discovery after another as they opened up the radio sky. With this collection of classic papers and the extensive intro­ ductory material, the reader can experience these exciting discoveries, as well as understand the developing techniques and follow the motivations which prompted the various lines of inquiry. For instance he or she will follow in detail the several attempts to detect radio waves from the sun at the turn of the century; the unravelling by Jansky of a "steady hiss type static"; the incredible story of Reber who built a 9 meter dish in his backyard in 1937 and then mapped the Milky Way; the vital discoveries by Hey and colleagues of radio bursts from the Sun and of a discrete source in the constellation of Cygnus; the development of re...

  18. GRO J1744-28, search for the counterpart: infrared photometry and spectroscopy

    NARCIS (Netherlands)

    Gosling, A.J.; Bandyopadhyay, R.M.; Miller Jones, J.C.A.; Farrell, S.A.

    2007-01-01

    Using VLT/ISAAC, we have detected two candidate counterparts to the bursting pulsar GRO J1744-28, one bright and one faint, both within the X-ray error circles found using XMM-Newton and Chandra. In determining the spectral types of the counterparts we applied three different extinction corrections;

  19. Blind surveys for radio pulsars and transients

    Science.gov (United States)

    Lorimer, D. R.

    2011-08-01

    The main reasons for searching for pulsars are to: (i) get an accurate census of the neutron star population and its origin and evolution; (ii) connect neutron stars to other stellar populations in the Galaxy and globular clusters; (iii) study Galactic astronomy (the interstellar medium and magnetic field) (iv) find and study new interesting individual objects; (v) study pulsar phenomenology; (vi) find pulsars to add to the sensitivity of pulsar timing arrays. This review focuses on blind (i.e. large area) searches for radio pulsars. I'll summarize the methods we use, some of the challenges they present, look at some of the recent and current efforts going on. I will also look at outreach of this area to groups outside the traditional area of pulsar research, highlight the discoveries of radio transients and look ahead to the future. Pulsars found at other wavelengths will be reviewed elsewhere in this volume.

  20. Tools of radio astronomy

    CERN Document Server

    Wilson, Thomas L; Hüttemeister, Susanne

    2013-01-01

    This 6th edition of “Tools of Radio Astronomy”, the most used introductory text in radio astronomy, has been revised to reflect the current state of this important branch of astronomy. This includes the use of satellites, low radio frequencies, the millimeter/sub-mm universe, the Cosmic Microwave Background and the increased importance of mm/sub-mm dust emission. Several derivations and presentations of technical aspects of radio astronomy and receivers, such as receiver noise, the Hertz dipole and  beam forming have been updated, expanded, re-worked or complemented by alternative derivations. These reflect advances in technology. The wider bandwidths of the Jansky-VLA and long wave arrays such as LOFAR and mm/sub-mm arrays such as ALMA required an expansion of the discussion of interferometers and aperture synthesis. Developments in data reduction algorithms have been included. As a result of the large amount of data collected in the past 20 years, the discussion of solar system radio astronomy, dust em...

  1. Radio Galaxy Zoo: A Search for Hybrid Morphology Radio Galaxies

    Science.gov (United States)

    Kapińska, A. D.; Terentev, I.; Wong, O. I.; Shabala, S. S.; Andernach, H.; Rudnick, L.; Storer, L.; Banfield, J. K.; Willett, K. W.; de Gasperin, F.; Lintott, C. J.; López-Sánchez, Á. R.; Middelberg, E.; Norris, R. P.; Schawinski, K.; Seymour, N.; Simmons, B.

    2017-12-01

    Hybrid morphology radio sources (HyMoRS) are a rare type of radio galaxy that display different Fanaroff-Riley classes on opposite sides of their nuclei. To enhance the statistical analysis of HyMoRS, we embarked on a large-scale search of these sources within the international citizen science project, Radio Galaxy Zoo (RGZ). Here, we present 25 new candidate hybrid morphology radio galaxies. Our selected candidates are moderate power radio galaxies ({L}{median}=4.7× {10}24 W Hz-1 sr-1) at redshifts 0.14 1 Mpc) radio galaxies, one resides at the center of a galaxy cluster, and one is hosted by a rare green bean galaxy. Although the origin of the hybrid morphology radio galaxies is still unclear, this type of radio source starts depicting itself as a rather diverse class. We discuss hybrid radio morphology formation in terms of the radio source environment (nurture) and intrinsically occurring phenomena (nature; activity cessation and amplification), showing that these peculiar radio galaxies can be formed by both mechanisms. While high angular resolution follow-up observations are still necessary to confirm our candidates, we demonstrate the efficacy of the RGZ in the pre-selection of these sources from all-sky radio surveys, and report the reliability of citizen scientists in identifying and classifying complex radio sources.

  2. Optical Counterparts of X-ray Sources in the Whirlpool Galaxy

    Science.gov (United States)

    Bichon, Luis

    2018-01-01

    We present preliminary results of our analysis of the optical counterparts of X-ray sources in the Whirlpool Galaxy (M51). We perform a multi-wavelength analysis of the X-ray sources in the Whirlpool Galaxy (M51) with the Hubble Space Telescope and the Chandra X-ray Observatory. We attempt to determine the nature of the X-ray binaries in M51, by estimating the age of the stellar counterparts. Here we present preliminary results of our analysis of the X-ray sources and their optical counterparts.

  3. Galactic radio astronomy

    CERN Document Server

    Sofue, Yoshiaki

    2017-01-01

    This book is a concise primer on galactic radio astronomy for undergraduate and graduate students, and provides wide coverage of galactic astronomy and astrophysics such as the physics of interstellar matter and the dynamics and structure of the Milky Way Galaxy and galaxies. Radio astronomy and its technological development have led to significant progress in galactic astronomy and contributed to understanding interstellar matter and galactic structures. The book begins with the fundamental physics of radio-wave radiation, i.e., black body radiation, thermal emission, synchrotron radiation, and HI and molecular line emissions. The author then gives overviews of ingredients of galactic physics, including interstellar matter such as the neutral (HI), molecular hydrogen, and ionized gases, as well as magnetic fields in galaxies. In addition, more advanced topics relevant to the Galaxy and galaxies are also contained here: star formation, supernova remnants, the Galactic Center and black holes, galactic dynamics...

  4. Radio frequency spectrum management

    Science.gov (United States)

    Sujdak, E. J., Jr.

    1980-03-01

    This thesis is a study of radio frequency spectrum management as practiced by agencies and departments of the Federal Government. After a brief introduction to the international agency involved in radio frequency spectrum management, the author concentrates on Federal agencies engaged in frequency management. These agencies include the National Telecommunications and Information Administration (NTIA), the Interdepartment Radio Advisory Committee (IRAC), and the Department of Defense (DoD). Based on an analysis of Department of Defense frequency assignment procedures, recommendations are given concerning decentralizing military frequency assignment by delegating broader authority to unified commanders. This proposal includes a recommendation to colocate the individual Service frequency management offices at the Washington level. This would result in reduced travel costs, lower manpower requirements, and a common tri-Service frequency management data base.

  5. CCD Astrometry of Selected Compact Extragalactic Radio Sources

    Science.gov (United States)

    Fedorov, P.; Velichko, F.; Filonenko, V.; Myznikov, A.; Sergeev, V.

    The 64 optical positions relative to the Catalog of Astrometric Standards (USNO-A2.0) and 9 optical positions relative to the Extragalactic Reference Link Catalog (de Vegt at al., 2001) had been obtained for the optical counterparts of 50 northern compact extragalactic radio sources (CERS). These positions were determined at the Kharkov Astronomical Observatory with use the CCD-camera ST-6 of the 0.7-m telescope AZT-8. More than 325 CCD-images of field 10.5' × 8' with optical counterparts of selected CERS had been obtained during 1997-2001. Positions of reference stars (from 6 to 12 stars for each CERS) were obtained from USNO-A2.0 catalogue, Extragalactic Reference Link Catalog and Nikolayev AMC catalogue (Pinigin & Shulga, 1999). The mean internal formal errors of the optical positions of these CERS are 100 mas in right ascension and 70 mas in declination. A comparison with VLBI radio positions for these sources is presented. The mean differences between radio and optical positions from our observations are not significantly differing from zero on the 0.05 significance level. The optical data which we obtained is potentially useful to possibly improve the current link of the Hipparcos reference frame to the ICRS. References de Vegt, C., Hindsley, R., Zacharias, N., Winter, L. 2001, AJ, 2815 Pinigin, G.I., Shulga A.V., 1999, Proc. JOURNESS 1999 & IX. Lohrmann-Kolloquium, Dresden (Germany), 64

  6. Exploring Radio Pulsars With New Technologies

    Science.gov (United States)

    Torne, Pablo

    2017-04-01

    scientific exploitation of the these four telescopes, I investigated technical aspects of two next-generation radio receivers planned for the the Effelsberg 100-m: the new Ultra-Broad-Band receiver (UBB), and the future Phased Array Feed (PAF). The tests for the UBB included the investigation of its optimum focusing set-up and its frequency-dependent system noise. We found the optimum focus to be that which optimized the gain at the highest frequencies of its operating band. We have also shown that the sensitivity of the UBB was significantly lower when the receiver is installed at the telescope (by a factor 3) in comparison to measurements taken in the laboratory. Our investigation points to strong Radio Frequency Interference (RFI) as the cause of this sensitivity deficit. I also designed and carried out the first scientific experiment with the UBB during its commissioning: a search for pulsars in detected gamma-ray sources with the Fermi Large Area Telescope (LAT) with no associated counterparts. No new radio pulsars were discovered in this survey, but the data analysis demonstrated that large parts of the observing frequency range ( 50-80 per cent) were unusable due to persistent RFI. We also showed that the strong RFI in the local environment made the receiver enter often into saturation. For the PAF, our tests at Effelsberg on a sample element of the future Checkerboard PAF MkII array confirmed that the front-end should be able to operate at Effelsberg without a persistent saturation by RFI. Overall, the results confirm that these new receivers can be used in electromagnetically-polluted areas, but require careful designs of the electronics in order to strongly suppress those frequency ranges particularly polluted by man-made radio signals.

  7. VizieR Online Data Catalog: MGRO J2019+37 region radio and IR observations (Paredes+, 2009)

    Science.gov (United States)

    Paredes, J. M.; Marti, J.; Ishwara-Chandra, C. H.; Sanchez-Sutil, J. R.; Munoz-Arjonilla, A. J.; Moldon, J.; Peracaula, M.; Luque-Escamilla, P. L.; Zabalza, V.; Bosch-Ramon, V.; Bordas, P.; Romero, G. E.; Ribo, M.

    2009-09-01

    This table contains information about all radio sources detected with the Giant Metrewave Radio Telescope (GMRT) of the National Centre for Radio Astrophysics (NCRA) in Khodad (India) in the MGRO J2019+37 region. The observations were carried out at 610MHz (49cm wavelength) in July 2007. An hexagonal pattern of 19 pointings was designed in order to cover the region of 2.5 square degree centered on the MGRO J2019+37 peak of emission. The list of sources was determined using the SExtractor automatic procedure over our 5" resolution radio mosaic. Only sources with peak ux density higher than about ten times the local noise after primary beam correction were included. There are 42 of the 362 detected radio sources inside the area imaged in the near-infrared Ks-band. A total of 6 out of these 42 sources have a near-infrared counterpart candidate within 0.6" of their radio position. On the other hand, a total of 41 of the 362 radio sources are located in fields observed in X-rays. In this case, 5 of the 41 radio sources have an X-ray counterpart candidate within 5" (the typical uncertainty for XMM-Newton). Both, the Ks magnitude and the X-ray flux, are listed when available. (1 data file).

  8. A reconfigurable radio architecture for Cognitive Radio in emergency networks

    NARCIS (Netherlands)

    Zhang, Q.; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2006-01-01

    Cognitive Radio has been proposed as a promising technology to solve today’s spectrum scarcity problem. Cognitive Radio is able to sense the spectrum to find the free spectrum, which can be optimally used by Cognitive Radio without causing interference to the licensed user. In the scope of the

  9. Radio spectra of Gigahertz Peaked Spectrum radio sources

    NARCIS (Netherlands)

    deVries, WH; Barthel, PD; ODea, CP

    A well defined sample of 72 Gigahertz Peaked Spectrum radio sources is compiled, having turnover frequencies in the range of 0.5 - 10 GHz. Using this sample, the canonical GPS radio spectrum is constructed, which is found to have a constant shape, independent of AGN type, redshift or radio

  10. Spectrum management and radio resource management considering cognitive radio systems

    NARCIS (Netherlands)

    Haartsen, J.C.; Wieweg, Lasse; Huschke, Jörg

    2005-01-01

    International fora and some national administrations define a cognitive radio (CR) as a pioneering radio communication system that would be capable of altering and adapting its transmitter and receiver parameters based on communication and the exchange of information with related detectable radio

  11. 75 FR 10439 - Cognitive Radio Technologies and Software Defined Radios

    Science.gov (United States)

    2010-03-08

    ... COMMISSION 47 CFR Part 2 Cognitive Radio Technologies and Software Defined Radios AGENCY: Federal... of Engineering and Technology, (202) 418-7506, e-mail: [email protected] . SUPPLEMENTARY... Order 1. On March 17, 2005, the Commission adopted the Cognitive Radio Report and Order, 70 FR 23032...

  12. X(3872) and the search for its bottomonium counterpart at the LHC

    CERN Document Server

    Toms, Konstantin; The ATLAS collaboration

    2016-01-01

    X(3872) history and theoretical status overview. ATLAS study of the ψ(2S) and X(3872) production. Search for X(3872) bottomonium counterpart by ATLAS. Search for Xb at CMS. Determination of X(3872) quantum numbers at LHCb.

  13. Infrared-faint radio sources in the SERVS deep fields. Pinpointing AGNs at high redshift

    Science.gov (United States)

    Maini, A.; Prandoni, I.; Norris, R. P.; Spitler, L. R.; Mignano, A.; Lacy, M.; Morganti, R.

    2016-12-01

    Context. Infrared-faint radio sources (IFRS) represent an unexpected class of objects which are relatively bright at radio wavelength, but unusually faint at infrared (IR) and optical wavelengths. A recent and extensive campaign on the radio-brightest IFRSs (S1.4 GHz≳ 10 mJy) has provided evidence that most of them (if not all) contain an active galactic nuclei (AGN). Still uncertain is the nature of the radio-faintest IFRSs (S1.4 GHz≲ 1 mJy). Aims: The scope of this paper is to assess the nature of the radio-faintest IFRSs, testing their classification and improving the knowledge of their IR properties by making use of the most sensitive IR survey available so far: the Spitzer Extragalactic Representative Volume Survey (SERVS). We also explore how the criteria of IFRSs can be fine-tuned to pinpoint radio-loud AGNs at very high redshift (z > 4). Methods: We analysed a number of IFRS samples identified in SERVS fields, including a new sample (21 sources) extracted from the Lockman Hole. 3.6 and 4.5 μm IR counterparts of the 64 sources located in the SERVS fields were searched for and, when detected, their IR properties were studied. Results: We compared the radio/IR properties of the IR-detected IFRSs with those expected for a number of known classes of objects. We found that IR-detected IFRSs are mostly consistent with a mixture of high-redshift (z ≳ 3) radio-loud AGNs. The faintest ones (S1.4 GHz 100 μJy), however, could be also associated with nearer (z 2) dust-enshrouded star-burst galaxies. We also argue that, while IFRSs with radio-to-IR ratios >500 can very efficiently pinpoint radio-loud AGNs at redshift 2 < z < 4, lower radio-to-IR ratios ( 100-200) are expected for higher redshift radio-loud AGNs.

  14. CLUSTERED RADIO INTERFEROMETRIC CALIBRATION

    NARCIS (Netherlands)

    Kazemi, S.; Yatawatta, S.; Zaroubi, S.

    2011-01-01

    This paper introduces an amendment to radio interferometric calibration of sources below the noise level. The main idea is to employ the information of the stronger sources' measured signals as a plug-in criterion to solve for the weaker ones. For this purpose, we construct a number of source

  15. Educational Broadcasting--Radio.

    Science.gov (United States)

    Ahamed, Uvais; Grimmett, George

    This manual is intended for those who must conduct educational radio broadcasting training courses in Asia-Pacific countries without the resources of experienced personnel, as well as for individuals to use in self-learning situations. The selection of material has been influenced by the need to use broadcasting resources effectively in programs…

  16. Radio Broadcast Technology

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 1. Radio Broadcast Technology. Harsh Vardhan. General Article Volume 7 Issue 1 January 2002 pp 53-63. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/01/0053-0063. Keywords. Hertzian ...

  17. Division x: Radio Astronomy

    NARCIS (Netherlands)

    Taylor, Russ; Chapman, Jessica; Rendong, Nan; Carilli, Christopher; Giovannini, Gabriele; Hills, Richard; Hirabayashi, Hisashi; Jonas, Justin; Lazio, Joseph; Morganti, Raffaella; Rubio, Monica; Shastri, Prajval

    This triennium has seen a phenomenal investment in development of observational radio astronomy facilities in all parts of the globe at a scale that significantly impacts the international community. This includes both major enhancements such as the transition from the VLA to the EVLA in North

  18. Torun Radio Astronomy Observatory

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    Torun Center for Astronomy is located at Piwnice, 15 km north of Torun, Poland. A part of the Faculty of Physics and Astronomy of the Nicolaus Copernicus University, it was created by the union of Torun Radio Astronomy Observatory (TRAO) and the Institute of Astronomy on 1 January 1997....

  19. Valuing commercial radio licences

    NARCIS (Netherlands)

    Kerste, M.; Poort, J.; van Eijk, N.

    2011-01-01

    Within the EU Regulatory Framework, licensees for commercial radio broadcasting may be charged a fee to ensure optimal allocation of scarce resources but not to maximize public revenues. In this paper, it is described how such a fee can be determined for the purpose of licence renewal or extension.

  20. Digital Low Frequency Radio Camera

    Science.gov (United States)

    Fullekrug, M.; Mezentsev, A.; Soula, S.; van der Velde, O.; Poupeney, J.; Sudre, C.; Gaffet, S.; Pincon, J.

    2012-04-01

    This contribution reports the design, realization and operation of a novel digital low frequency radio camera towards an exploration of the Earth's electromagnetic environment with particular emphasis on lightning discharges and subsequent atmospheric effects such as transient luminous events. The design of the digital low frequency radio camera is based on the idea of radio interferometry with a network of radio receivers which are separated by spatial baselines comparable to the wavelength of the observed radio waves, i.e., ~1-100 km which corresponds to a frequency range from ~3-300 kHz. The key parameter towards the realization of the radio interferometer is the frequency dependent slowness of the radio waves within the Earth's atmosphere with respect to the speed of light in vacuum. This slowness is measured with the radio interferometer by using well documented radio transmitters. The digital low frequency radio camera can be operated in different modes. In the imaging mode, still photographs show maps of the low frequency radio sky. In the video mode, movies show the dynamics of the low frequency radio sky. The exposure time of the photograhps, the frame rate of the video, and the radio frequency of interest can be adjusted by the observer. Alternatively, the digital radio camera can be used in the monitoring mode, where a particular area of the sky is observed continuously. The first application of the digital low frequency radio camera is to characterize the electromagnetic energy emanating from sprite producing lightning discharges, but it is expected that it can also be used to identify and investigate numerous other radio sources of the Earth's electromagnetic environment.

  1. The Current Status of Low Frequency Radio Astronomy from Space

    Science.gov (United States)

    Kaiser, M. L.; Weiler, K. W.

    Ground-based radio astronomy is severely limited by the Earth's ionosphere. Below 15 -- 20 MHz, space-based radio observations are superior or even mandatory. Three different areas of astronomical research manifest themselves at low radio frequencies: solar, planetary, and galactic-extragalactic. Space-based observations of solar phenomena at low frequencies are a natural extension of high-frequency ground-based observations that have been carried out since the beginnings of radio astronomy. Measurements of known solar phenomena such as Types II and III bursts have been extended from the few solar radii altitude range reachable by ground-based techniques out to 1 AU and beyond. These space-based solar measurements have become critical in our developing an understanding of ``space weather." In contrast, non-thermal planetary radio emissions are almost exclusively a space radio astronomy phenomenon. With the exception of two components of Jupiter's complex radio spectrum, the magnetospheric and Auroral radio emissions of Earth, Jupiter, Saturn, Uranus, and Neptune have all been discovered by space radio astronomy techniques. For astrophysical applications, the lack of angular resolution from space at low frequencies has thwarted progress such that most areas still remain to be fully exploited. Results to date have only included overall cosmic background spectra and extremely crude (~1 steradian resolution) ``maps." In this overview we will briefly summarize the current status of science in the three areas of research and outline some future concepts for low-frequency, space-based instruments for solar, planetary, and astrophysical problems.

  2. Ham Radio is Mir Magic.

    Science.gov (United States)

    Evans, Gary

    1997-01-01

    Presents a classroom activity in which students communicated with U.S. and Russian astronauts via ham radio while they were in orbit on the space station Mir. Gives suggestions for other ham radio classroom activities as well as names of organizations, publications, and grant programs that teachers can access to help in bring ham radio into their…

  3. HOW ELSE CAN WE DETECT FAST RADIO BURSTS?

    Energy Technology Data Exchange (ETDEWEB)

    Lyutikov, Maxim [Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907-2036 (United States); Lorimer, Duncan R., E-mail: lyutikov@purdue.edu [Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506-6315 (United States)

    2016-06-20

    We discuss possible electromagnetic signals accompanying Fast Radio Bursts (FRBs) that are expected in the scenario where FRBs originate in neutron star magnetospheres. For models involving Crab-like giant pulses, no appreciable contemporaneous emission is expected at other wavelengths. However, magnetar giant flares, driven by the reconfiguration of the magnetosphere, can produce both contemporaneous bursts at other wavelengths as well as afterglow-like emission. We conclude that the best chances are: (i) prompt short GRB-like emission, (ii) a contemporaneous optical flash that can reach naked eye peak luminosity (but only for a few milliseconds), and (iii) a high-energy afterglow emission. Case (i) could be tested by coordinated radio and high-energy experiments. Case (ii) could be seen in a coordinated radio-optical surveys, e.g., by the Palomar Transient Factory in a 60 s frame as a transient object of m = 15–20 mag with an expected optical detection rate of about 0.1 hr{sup −1}, an order of magnitude higher than in radio. Shallow, but large-area sky surveys such as ASAS-SN and EVRYSCOPE could also detect prompt optical flashes from the more powerful Lorimer-burst clones. The best constraints on the optical to radio power for this kind of emission could be provided by future observations with facilities like Large Synoptic Survey Telescope. Case (iii) might be seen in relatively rare cases that the relativistically ejected magnetic blob is moving along the line of sight.

  4. Extragalactic radio continuum surveys and the transformation of radio astronomy

    Science.gov (United States)

    Norris, Ray P.

    2017-10-01

    Next-generation radio surveys are about to transform radio astronomy by discovering and studying tens of millions of previously unknown radio sources. These surveys will provide fresh insights for understanding the evolution of galaxies, measuring the evolution of the cosmic star-formation rate, and rivalling traditional techniques in the measurement of fundamental cosmological parameters. By observing a new volume of observational parameter space, they are also likely to discover unexpected phenomena. This Review traces the evolution of extragalactic radio continuum surveys from the earliest days of radio astronomy to the present, and identifies the challenges that must be overcome to achieve this transformational change.

  5. INOVASI RADIO KAMPUS (RANCANG BANGUN RADIO UDINUS DENGAN INOVASI TEKNOLOGI @RADIO

    Directory of Open Access Journals (Sweden)

    Wellia Shinta Sari

    2014-08-01

    Full Text Available Perkembangan Teknologi Informasi dan Komunikasi (TIK memaksa industri penyiaran untuk ikut menyesuaikan diri. Radio konvensional bisa jadi akan tertinggal jika tidak melakukan inovasi teknologi yang ada. Begitu juga dengan radio kampus, yang keberadaannya sangat dibutuhkan sebagai wadah kreativitas dan sarana pembelajaran di sebuah universitas, apalagi yang memiliki program studi penyiaran. Radio kampus Suara Dian yang masih konvensional sehingga hampir kehilangan eksistensinya harus segera dibenahi dan dihidupkan kembali dengan mengikuti perkembangan teknologi di era konvergensi. Metode Inovasi teknologi yang bisa dilakukan adalah dengan menggunakan teknologi @Radio Streaming, yang bukan sekedar streaming, tapi juga optimalisasi teknologi yang terintegrasi dinamis melalui RISE (Radio Broadcasting Integrated System. Dengan berbagai fitur unggul dari inovasi teknologi tersebut, maka diharapkan Radio kampus Udinus ”Suara Dian” dapat kembali hidup, berkembang dan lebih kompetitif ditengah industri penyiaran Radio. Kata kunci : radio, kampus, konvergensi, streaming.

  6. Configurable SDR Operation for Cognitive Radio Applications using GNU Radio and the Universal Software Radio Peripheral

    OpenAIRE

    Scaperoth, David Alan

    2007-01-01

    With interoperability issues plaguing emergency responders throughout the country, Cognitive Radio (CR) offers a unique solution to streamline communication between police, Emergency Medical Technicians (EMT), and military officers. Using Software Defined Radio (SDR) technology, a flexible radio platform can be potentially configured using a Cognitive Engine (CE) to transmit and receive many different incompatible radio standards. In this thesis, an interface between a Cognitive Engine and...

  7. Multifrequency radio frequency sensing with photonics-assisted spectrum compression.

    Science.gov (United States)

    Yin, Feifei; Gao, Yuyang; Dai, Yitang; Zhang, Junyi; Xu, Kun; Zhang, Ziping; Li, Jianqiang; Lin, Jintong

    2013-11-01

    We propose and demonstrate a multifrequency radio frequency (RF) spectrum estimation technology. With photonic assistance, a multifrequency RF signal ranging from 0 to 1 GHz is highly spectrally compressed and sensed using a single analog-to-digital converter with analog bandwidth of 42.6 MHz. By calculating the cross correlation of pseudo random binary sequence and the encoded signal, up to 40 RF tones are precisely recognized without large computational load. The employment of optical mixing decreased the cost and increased the performance compared to its electrical counterpart. The theory and performance are also discussed.

  8. The Concept of 'Radio Music'

    DEFF Research Database (Denmark)

    Fjeldsøe, Michael

    2016-01-01

    , educational and didactic effort which would enlighten all of society. For a while it seemed that radio music was considered a genre of its own. To fulfil its function, radio music had to consider technical limitations as well as the educational level and listening modes of the new mass audience. Public radio......, as discussed by Kurt Weill and Paul Hindemith, was at first greeted with great expectations, but soon a more realistic attitude prevailed. Weill, himself a radio critic as well, composed Der Lindberghflug (1929) as a piece of ‘radio music theatre’, but then changed some of its features in order to turn...... it into a didactical play for amateurs, a so-called Lehrstück. The article will present the concept of ‘radio music’ developed within German Neue Sachlichkeit and discuss the relevance of such a concept for current research in the field of radio and music....

  9. Tools of radio astronomy

    CERN Document Server

    Wilson, Thomas L; Hüttemeister, Susanne

    2009-01-01

    The recent years have seen breathtaking progress in technology, especially in the receiver and digital technologies relevant for radio astronomy, which has at the same time advanced to shorter wavelengths. This is the updated and completely revised 5th edition of the most used introductory text in radio astronomy. It presents a unified treatment of the entire field from centimeter to sub-millimeter wavelengths. Topics covered include instruments, sensitivity considerations, observational methods and interpretations of the data recorded with both single dishes and interferometers. This text is useful to both students and experienced practicing astronomers. Besides making major updates and additions throughout the book, the authors have re-organized a number of chapters to more clearly separate basic theory from rapidly evolving practical aspects. Further, problem sets have been added at the end of each chapter.

  10. Massive scalar counterpart of gravitational waves in scalarized neutron star binaries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing [Sun Yat-sen University, School of Physics and Astronomy, Guangzhou (China)

    2017-09-15

    In analogy with spontaneous magnetization of ferromagnets below the Curie temperature, a neutron star (NS), with a compactness above a certain critical value, may undergo spontaneous scalarization and exhibit an interior nontrivial scalar configuration. Consequently, the exterior spacetime is changed, and an external scalar field appears, which subsequently triggers a scalarization of its companion. The dynamical interplay produces a gravitational scalar counterpart of tensor gravitational waves. In this paper, we resort to scalar-tensor theory and demonstrate that the gravitational scalar counterpart from a double neutron star (DNS) and a neutron star-white dwarf (NS-WD) system become massive. We report that (1) a gravitational scalar background field, arising from convergence of external scalar fields, plays the role of gravitational scalar counterpart in scalarized DNS binary, and the appearance of a mass-dimensional constant in a Higgs-like gravitational scalar potential is responsible for a massive gravitational scalar counterpart with a mass of the order of the Planck scale; (2) a dipolar gravitational scalar radiated field, resulting from differing binding energies of NS and WD, plays the role of a gravitational scalar counterpart in scalarized orbital shrinking NS-WDs, which oscillates around a local and scalar-energy-density-dependent minimum of the gravitational scalar potential and obtains a mass of the order of about 10{sup -21} eV/c{sup 2}. (orig.)

  11. Massive scalar counterpart of gravitational waves in scalarized neutron star binaries

    Science.gov (United States)

    Wang, Jing

    2017-09-01

    In analogy with spontaneous magnetization of ferromagnets below the Curie temperature, a neutron star (NS), with a compactness above a certain critical value, may undergo spontaneous scalarization and exhibit an interior nontrivial scalar configuration. Consequently, the exterior spacetime is changed, and an external scalar field appears, which subsequently triggers a scalarization of its companion. The dynamical interplay produces a gravitational scalar counterpart of tensor gravitational waves. In this paper, we resort to scalar-tensor theory and demonstrate that the gravitational scalar counterpart from a double neutron star (DNS) and a neutron star-white dwarf (NS-WD) system become massive. We report that (1) a gravitational scalar background field, arising from convergence of external scalar fields, plays the role of gravitational scalar counterpart in scalarized DNS binary, and the appearance of a mass-dimensional constant in a Higgs-like gravitational scalar potential is responsible for a massive gravitational scalar counterpart with a mass of the order of the Planck scale; (2) a dipolar gravitational scalar radiated field, resulting from differing binding energies of NS and WD, plays the role of a gravitational scalar counterpart in scalarized orbital shrinking NS-WDs, which oscillates around a local and scalar-energy-density-dependent minimum of the gravitational scalar potential and obtains a mass of the order of about 10^{-21} { {eV/c}}^2.

  12. RADIO EMISSION FROM RED-GIANT HOT JUPITERS

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Yuka [Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8550 (Japan); Spiegel, David S. [Analytics and Algorithms, Stitch Fix, San Francisco, CA 94103 (United States); Mroczkowski, Tony [Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 (United States); Nordhaus, Jason [Department of Science and Mathematics, National Technical Institute for the Deaf, Rochester Institute of Technology, Rochester, NY 14623 (United States); Zimmerman, Neil T. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Parsons, Aaron R. [Astronomy Department, University of California, Berkeley, CA (United States); Mirbabayi, Mehrdad [Astrophysics Department, Institute for Advanced Study, Princeton, NJ 08540 (United States); Madhusudhan, Nikku, E-mail: yuka.fujii@elsi.jp [Astronomy Department, University of Cambridge (United Kingdom)

    2016-04-01

    When planet-hosting stars evolve off the main sequence and go through the red-giant branch, the stars become orders of magnitudes more luminous and, at the same time, lose mass at much higher rates than their main-sequence counterparts. Accordingly, if planetary companions exist around these stars at orbital distances of a few au, they will be heated up to the level of canonical hot Jupiters and also be subjected to a dense stellar wind. Given that magnetized planets interacting with stellar winds emit radio waves, such “Red-Giant Hot Jupiters” (RGHJs) may also be candidate radio emitters. We estimate the spectral auroral radio intensity of RGHJs based on the empirical relation with the stellar wind as well as a proposed scaling for planetary magnetic fields. RGHJs might be intrinsically as bright as or brighter than canonical hot Jupiters and about 100 times brighter than equivalent objects around main-sequence stars. We examine the capabilities of low-frequency radio observatories to detect this emission and find that the signal from an RGHJ may be detectable at distances up to a few hundred parsecs with the Square Kilometer Array.

  13. Radio Emission from Red-Giant Hot Jupiters

    Science.gov (United States)

    Fujii, Yuka; Spiegel, David S.; Mroczkowski, Tony; Nordhaus, Jason; Zimmerman, Neil T.; Parsons, Aaron R.; Mirbabayi, Mehrdad; Madhusudhan, Nikku

    2016-01-01

    When planet-hosting stars evolve off the main sequence and go through the red-giant branch, the stars become orders of magnitudes more luminous and, at the same time, lose mass at much higher rates than their main sequence counterparts. Accordingly, if planetary companions exist around these stars at orbital distances of a few au, they will be heated up to the level of canonical hot Jupiters and also be subjected to a dense stellar wind. Given that magnetized planets interacting with stellar winds emit radio waves, such "Red-Giant Hot Jupiters" (RGHJs) may also be candidate radio emitters. We estimate the spectral auroral radio intensity of RGHJs based on the empirical relation with the stellar wind as well as a proposed scaling for planetary magnetic fields. RGHJs might be intrinsically as bright as or brighter than canonical hot Jupiters and about 100 times brighter than equivalent objects around main-sequence stars. We examine the capabilities of low-frequency radio observatories to detect this emission and find that the signal from an RGHJ may be detectable at distances up to a few hundred parsecs with the Square Kilometer Array.

  14. Radio Frequency Spectrum Management

    Science.gov (United States)

    1980-03-01

    limits, emmission standards, etc., cover many pages. Other available non-technical policy statements are of the motherhood-and-apple-pie ilk. Further...and 2) by allowing the onscene commander who is acutely aware of the radio frequency emmission environment in his area to make assignments. The author...need for investment in specific human capi- tal vice on the job experience, it will never eliminate it. Rather vice education and training in

  15. Programme driven music radio

    OpenAIRE

    Hayes, Conor; Cunningham, Padraig; Clerkin, Patrick; Grimaldi, Marco

    2002-01-01

    This paper describes the operation of and research behind a networked application for the delivery of personalised streams of music at Trinity College Dublin. Smart Radio is a web based client-server application that uses streaming audio technology and recommendation techniques to allow users build, manage and share music programmes. While it is generally acknowledged that music distribution over the web will dramatically change how the music industry operates, there are ...

  16. Radio Telescope Reflectors

    Science.gov (United States)

    Baars, Jacob W. M.; Kärcher, Hans J.

    2017-11-01

    This book demonstrates how progress in radio astronomy is intimately linked to the development of reflector antennas of increasing size and precision. The authors describe the design and construction of major radio telescopes as those in Dwingeloo, Jodrell Bank, Parkes, Effelsberg and Green Bank since 1950 up to the present as well as millimeter wavelength telescopes as the 30m MRT of IRAM in Spain, the 50m LMT in Mexico and the ALMA submillimeter instrument. The advances in methods of structural design and coping with environmental influences (wind, temperature, gravity) as well as application of new materials are explained in a non-mathematical, descriptive and graphical way along with the story of the telescopes. Emphasis is placed on the interplay between astronomical and electromagnetic requirements and structural, mechanical and control solutions. A chapter on management aspects of large telescope projects closes the book. The authors address a readership with interest in the progress of engineering solutions applied to the development of radio telescope reflectors and ground station antennas for satellite communication and space research. The book will also be of interest to historians of science and engineering with an inclination to astronomy.

  17. Danmarks Radios stemmer

    DEFF Research Database (Denmark)

    Lawaetz, Anna

    kanalspeakerne kändisser, hvis fortalelser i æteren såvel som private gøren og laden blev fulgt nøje i dagspressen. Anna Lawaetz har med ph.d.-afhandlingen Danmarks Radios stemmer med udgangspunkt i kanalspeakerne på P1 i perioden 1925-2012 gennem empiriske studier kortlagt fortællingen om institutionens stemmer...... – nøje udvalgte ikke-fiktionsstemmer i Danmarks Radio igennem tiden. Samtidig har hun lavet en konkret analyse af stemmerne baseret på både akustiske målinger og kategorisering af oplevelsen af stemmerne. Fx taler kanalspeakerne på P1 i dag ikke hurtigere end tidligere, men pauserne er blevet kortere...... datamængder kræver udvikling af nye metoder. Den metodiske udvikling har her været baseret på optagelser af stemmer for at undersøge hvordan man videnskabeligt kan arbejde med optagelser af stemmer som mere end teksttransskriptioner inden for det kulturvidenskabelige felt med afsæt i Danmarks Radios...

  18. Observations of the First Electromagnetic Counterpart to a Gravitational-wave Source by the TOROS Collaboration

    Science.gov (United States)

    Díaz, M. C.; Macri, L. M.; Garcia Lambas, D.; Mendes de Oliveira, C.; Nilo Castellón, J. L.; Ribeiro, T.; Sánchez, B.; Schoenell, W.; Abramo, L. R.; Akras, S.; Alcaniz, J. S.; Artola, R.; Beroiz, M.; Bonoli, S.; Cabral, J.; Camuccio, R.; Castillo, M.; Chavushyan, V.; Coelho, P.; Colazo, C.; Costa-Duarte, M. V.; Cuevas Larenas, H.; DePoy, D. L.; Domínguez Romero, M.; Dultzin, D.; Fernández, D.; García, J.; Girardini, C.; Gonçalves, D. R.; Gonçalves, T. S.; Gurovich, S.; Jiménez-Teja, Y.; Kanaan, A.; Lares, M.; Lopes de Oliveira, R.; López-Cruz, O.; Marshall, J. L.; Melia, R.; Molino, A.; Padilla, N.; Peñuela, T.; Placco, V. M.; Quiñones, C.; Ramírez Rivera, A.; Renzi, V.; Riguccini, L.; Ríos-López, E.; Rodriguez, H.; Sampedro, L.; Schneiter, M.; Sodré, L.; Starck, M.; Torres-Flores, S.; Tornatore, M.; Zadrożny, A.

    2017-10-01

    We present the results of prompt optical follow-up of the electromagnetic counterpart of the gravitational-wave event GW170817 by the Transient Optical Robotic Observatory of the South Collaboration. We detected highly significant dimming in the light curves of the counterpart ({{Δ }}g=0.17+/- 0.03 mag, {{Δ }}r=0.14+/- 0.02 mag, {{Δ }}I=0.10+/- 0.03 mag) over the course of only 80 minutes of observations obtained ˜35 hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ˜59 hr after the event with the EABA 1.5 m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a “blue kilonova” relatively free of lanthanides.

  19. Infrared Faint Radio Sources in the Extended Chandra Deep Field South

    Science.gov (United States)

    Huynh, Minh T.

    2009-01-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey (ATLAS) which have no observable counterpart in the Spitzer Wide-area Infrared Extragalactic Survey (SWIRE). The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6 to 70 micron) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the SED of these objects shows that they are consistent with high redshift AGN (z > 2).

  20. Results from GROCSE I: A real-time search for gamma ray burst optical counterparts

    Science.gov (United States)

    Lee, B.; Akerlof, C.; Ables, E.; Bionta, R. M.; Ott, L.; Park, H. S.; Parker, E.; Barthelmy, S.; Butterworth, P.; Cline, T.

    1995-01-01

    The GROCSE I experiment (Gamma-Ray Optical Counterpart Search Experiment) is a rapid slewing wide field of view optical telescope at Lawrence Livermore National Laboratory which responds to triggers from the BATSE GRB data telemetry stream that have been processed and distributed by the BACODINE network. GROCSE 1 has been in continuous automated operation since January 1994. As of October 1995, sky images for 22 GRB triggers have been recorded, in some cases while the burst was still emitting gamma rays. The preliminary analysis of eight of these events are presented here. No optical counterparts have yet been detected. Limits for optical emission are given.

  1. XMM-Newton Observations Reveal the X-ray Counterpart of the Very-high-energy gamma-ray Source HESS J1640-465

    Energy Technology Data Exchange (ETDEWEB)

    Funk, S.; Hinton, J.A.; Puhlhofer, G.; Aharonian, F.A.; Hofmann, W.; Reimer, O.; Wagner, S.; /KIPAC, Menlo Park /Heidelberg, Max Planck Inst. /Leeds U. /Dublin Inst. /Stanford U., HEPL; Funk, S.; Hinton, J.A.; Puehlhofer, G.; Aharonian, F.A.; Hofmann, W.; Reimer, O.; Wagner, S.

    2007-03-05

    We present X-ray observations of the as of yet unidentified very high-energy (VHE) {gamma}-ray source HESS J1640-465 with the aim of establishing a counterpart of this source in the keV energy range, and identifying the mechanism responsible for the VHE emission. The 21.8 ksec XMM-Newton observation of HESS J1640-465 in September 2005 represents a significant improvement in sensitivity and angular resolution over previous ASCA studies in this region. These new data show a hard-spectrum X-ray emitting object at the centroid of the H.E.S.S. source, within the shell of the radio Supernova Remnant (SNR) G338.3-0.0. This object is consistent with the position and flux previously measured by both ASCA and Swift-XRT but is now shown to be significantly extended. We argue that this object is very likely the counterpart to HESS J1640-465 and that both objects may represent the Pulsar Wind Nebula of an as of yet undiscovered pulsar associated with G338.3-0.0.

  2. The Optical Counterpart to the Accreting Millisecond X-Ray Pulsar SAX J1748.9-2021 in the Globular Cluster NGC 6440

    Science.gov (United States)

    Cadelano, M.; Pallanca, C.; Ferraro, F. R.; Dalessandro, E.; Lanzoni, B.; Patruno, A.

    2017-07-01

    We used a combination of deep optical and {{H}}α images of the Galactic globular cluster NGC 6440, acquired with the Hubble Space Telescope, to identify the optical counterpart to the accreting millisecond X-ray pulsar SAX J1748.9-2021 during quiescence. A strong {{H}}α emission has been detected from a main-sequence star (hereafter COM-SAX J1748.9-2021) located at only 0.″15 from the nominal position of the X-ray source. The position of the star also agrees with the optical counterpart found by Verbunt et al. during an outburst. We propose this star as the most likely optical counterpart to the binary system. By direct comparison with isochrones, we estimated that COM-SAX J1748.9-2021 has a mass of 0.70{--}0.83 {M}⊙ , a radius of 0.88+/- 0.02 {R}⊙ , and a superficial temperature of 5250 ± 80 K. These parameters, combined with the orbital characteristics of the binary, suggest that the system is observed at a very low inclination angle (˜ 8^\\circ {--}14^\\circ ) and that the star is filling or even overflowing its Roche lobe. This, together with the EW of the {{H}}α emission (˜20 Å), suggests possible ongoing mass transfer. The possible presence of such an ongoing mass transfer during a quiescence state also suggests that the radio pulsar is not active yet and thus this system, despite its similarity with the class of redback millisecond pulsars, is not a transitional millisecond pulsar. Based on observations collected with the NASA/ESA HST (Prop. 12517, 13410), obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555.

  3. Flexible Adaptation in Cognitive Radios

    CERN Document Server

    Li, Shujun

    2013-01-01

    This book provides an introduction to software-defined radio and cognitive radio, along with methodologies for applying knowledge representation, semantic web, logic reasoning and artificial intelligence to cognitive radio, enabling autonomous adaptation and flexible signaling. Readers from the wireless communications and software-defined radio communities will use this book as a reference to extend software-defined radio to cognitive radio, using the semantic technology described. Readers with a background in semantic web and artificial intelligence will find in this book the application of semantic web and artificial intelligence technologies to wireless communications. For readers in networks and network management, this book presents a new approach to enable interoperability, collaborative optimization and flexible adaptation of network components. Provides a comprehensive ontology covering the core concepts of wireless communications using a formal language; Presents the technical realization of using a ...

  4. Expression of EGFRvIII in Glioblastoma: Prognostic Significance Revisited

    Directory of Open Access Journals (Sweden)

    Nicola Montano

    2011-12-01

    Full Text Available The epidermal growth factor receptor variant III (EGFRvIII is associated with increased proliferation of glioma cells. However, the impact of EGFRvIII on survival of patients with glioblastoma (GBM has not been definitively established. In the present study, we prospectively evaluated 73 patients with primary GBM treated with surgical resection and standard radio/chemotherapy. The EGFRvIII was assessed by reverse transcription–polymerase chain reaction (PCR, O6-methylguanine methyltransferase (MGMT promoter methylation was assessed by methylation-specific PCR, and phosphatase and tension homolog (PTEN expression was assessed by immunohistochemistry. In 14 patients of this series, who presented with tumor recurrence, EGFRvIII was determined by real-time PCR. Sensitivity to temozolomide (TMZ was assessed in vitro on GBM neurosphere cell cultures with different patterns of EGFRvIII expression. Age 60 years or younger, preoperative Karnofsky Performance Status score of 70 or higher, recursive partitioning analysis score III and IV, methylated MGMT, and Ki67 index of 20% or less were significantly associated with longer overall survival (OS; P = .0069, P =.0035, P = .0007, P = .0437, and P = .0286, respectively. EGFRvIII identified patients with significantly longer OS (P = .0023 and the association of EGFRvIII/Ki67 of 20% or less, EGFRvIII/normal PTEN, EGFRvIII/methylated MGMT, and EGFRvIII/normal PTEN/methylated MGMT identified subgroups of GBM patients with better prognosis. In recurred GBMs, EGFRvIII expression was approximately two-fold lower than in primary tumors. In vitro, the EGFRvIII-negative GBM neurosphere cells were more resistant to TMZ than the positive ones. In conclusion, in contrast with previous studies, we found that EGFRvIII is associated with prolonged survival of GBM patients treated with surgery and radio/chemotherapy. Depletion of EGFRvIII in recurrent GBMs as well as differential sensitivity to TMZ in vitro indicates that

  5. Software defined radio architectures evaluation

    OpenAIRE

    Palomo, Alvaro; Villing, Rudi; Farrell, Ronan

    2008-01-01

    This paper presents an performance evaluation of GNU Radio and OSSIE, two open source Software Defined Radio (SDR) architectures. The two architectures were compared by running implementations of a BPSK waveform utilising a software loopback channel on each. The upper bound full duplex throughput was found to be around 700kbps in both cases, though OSSIE was slightly faster than GNU Radio. CPU and memory loads did not differ significantly.

  6. Uzaybimer Radio Telescope Control System

    Science.gov (United States)

    Balbay, R.; Öz, G. K.; Arslan, Ö.; Özeren, F. F.; Küçük, İ.

    2016-12-01

    A 13 meters former NATO radar is being converted into a radio telescope. The radio telescope is controlled by a system which has been developed at UZAYBİMER. The Telescope Control System(TCS) has been designed using modern industrial systems. TCS has been developed in LabView platform in which works Windows embedded OS. The position feedback used on radio telescopes is an industrial EtherCAT standard. ASCOM library is used for astronomical calculations.

  7. A “Cosmic Comb” Model of Fast Radio Bursts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bing [Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154 (United States)

    2017-02-20

    Recent observations of fast radio bursts (FRBs) indicate a perplexing, inconsistent picture. We propose a unified scenario to interpret diverse FRBs observed. A regular pulsar, otherwise unnoticeable at a cosmological distance, may produce a bright FRB if its magnetosphere is suddenly “combed” by a nearby, strong plasma stream toward the anti-stream direction. If the Earth is to the night side of the stream, the combed magnetic sheath would sweep across the direction of Earth and make a detectable FRB. The stream could be an AGN flare, a GRB or supernova blastwave, a tidal disruption event, or even a stellar flare. Since it is the energy flux received by the pulsar rather than the luminosity of the stream origin that defines the properties of the FRB, this model predicts a variety of counterparts of FRBs, including a possible connection between FRB 150418 and an AGN flare, a possible connection between FRB 131104 and a weak GRB, a steady radio nebula associated with the repeating FRB 121102, and probably no bright counterparts for some FRBs.

  8. Pluralismo, radio e Internet

    Directory of Open Access Journals (Sweden)

    Bruce Girard

    2015-01-01

    Full Text Available En muchas ocasiones de ha oído hablar que internet y las nuevas tecnologías de la comunicación llevarán a la humanidad a un mundo homogeneizado en donde todos compartirán la misa cultura del “ciberespacio” y hablarán el mismo lenguaje. Nuevas iniciativas en América Latina combinan la tecnología de punta y la radio para poner fin a este mito y contribuir a una comunicación más democrática.

  9. Internet Resources for Radio Astronomy

    Science.gov (United States)

    Andernach, H.

    A subjective overview of Internet resources for radio-astronomical information is presented. Basic observing techniques and their implications for the interpretation of publicly available radio data are described, followed by a discussion of existing radio surveys, their level of optical identification, and nomenclature of radio sources. Various collections of source catalogues and databases for integrated radio source parameters are reviewed and compared, as well as the web interfaces to interrogate the current and ongoing large-area surveys. Links to radio observatories with archives of raw (uv-) data are presented, as well as services providing images, both of individual objects or extracts (``cutouts'') from large-scale surveys. While the emphasis is on radio continuum data, a brief list of sites providing spectral line data, and atomic or molecular information is included. The major radio telescopes and surveys under construction or planning are outlined. A summary is given of a search for previously unknown optically bright radio sources, as performed by the students as an exercise, using Internet resources only. Over 200 different links are mentioned and were verified, but despite the attempt to make this report up-to-date, it can only provide a snapshot of the situation as of mid-1998.

  10. Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports the design, manufacture, and test of antenna systems. The facility is also used as an electromagnetic compatibility/radio frequency interference...

  11. Radio-induced brain lesions

    Directory of Open Access Journals (Sweden)

    Gorgan Mircea Radu

    2014-03-01

    Full Text Available Introduction : Radiotherapy, an important tool in multimodal oncologic treatment, can cause radio-induced brain lesion development after a long period of time following irradiation.

  12. Cyclic Fatigue Resistance of 3 Proprietary Rotary File Brands and their Analogous EdgeEndo Counterparts.

    Science.gov (United States)

    2018-04-26

    PROJECT NUMBER Maj Weyh, David 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION...resistance of proprietary files versus their EdgeEndo counterparts were identified. Acknowledgements: Maj David H. Weyh, DDS, Resident, Air Force

  13. Stability patterns for a size-structured population model and its stage-structured counterpart

    DEFF Research Database (Denmark)

    Zhang, Lai; Pedersen, Michael; Lin, Zhigui

    2015-01-01

    In this paper we compare a general size-structured population model, where a size-structured consumer feeds upon an unstructured resource, to its simplified stage-structured counterpart in terms of equilibrium stability. Stability of the size-structured model is understood in terms of an equivale...... to the population level....

  14. The Optical Identification of the Luminous Radio Galaxy 0409-752

    Science.gov (United States)

    Alvarez, H.; Aparici, J.; May, J.; Navarrete, M.

    1993-04-01

    We have identified the radio source 0409 - 752 with a faint (V = 21.6) galaxy which has emission lines of [O II] 3727 (strong), [O III] 4959, 5007 (strong) and [Ne III] 3869 (weak), consistent with a redshift of 0.694. Assuming a cosmological redshift, and using different values for H_0_ and q_0_, we have computed the absolute luminosity in the range 45-8400 MHz. A careful comparison with radio galaxies Cyg A and 3C 295, taken as reference because they are luminous and their spectra are accurately known in that frequency range, shows that 0409 - 752 is even slightly more powerful. The ratio of radio to optical luminosities for 0409 - 752 is very close to the highest known for radio galaxies. We found that the IRAS point source 04099 - 7514 is actually associated to a S0 galaxy in the field.

  15. Premerger Localization of Gravitational Wave Standard Sirens with LISA: Triggered Search for an Electromagnetic Counterpart

    Science.gov (United States)

    Kocsis, Bence; Haiman, Zoltán; Menou, Kristen

    2008-09-01

    Electromagnetic (EM) counterparts to SMBH binary mergers observed by LISA can be localized to within the field of view of astronomical instruments (~10 deg2) hours to weeks prior to coalescence. The temporal coincidence of any prompt EM counterpart with a gravitationally timed merger may offer the best chance of identifying a unique host galaxy. We discuss the challenges posed by searches for such prompt EM counterparts and propose novel observational strategies to address them. In particular, we discuss the size and shape evolution of the LISA localization error ellipses on the sky and quantify the corresponding requirements for dedicated EM surveys of the area prior to coalescence. A triggered EM counterpart search campaign will require monitoring a several square degree area. It could aim for variability at the 24-27 mag level in optical bands, for example, which corresponds to 1%-10% of the Eddington luminosity of the prime LISA sources of ~106-107 M⊙ BHs at z = 1-2, on timescales of minutes to hours, the orbital timescale of the binary in the last 2-4 weeks of coalescence. A cross-correlation of the period of any variable EM signal with the quasi-periodic gravitational waveform over 10-1000 cycles may aid the detection. Alternatively, EM searches can detect a transient signal accompanying the coalescence. The triggered searches will be ambitious, but if they successfully identify a unique prompt EM counterpart, they will enable new fundamental tests of gravitational physics. We highlight the measurement of differences in the arrival times of photons and gravitons from the same cosmological source as a valuable independent test of the massive character of gravity and of possible violations of Lorentz invariance in the gravity sector.

  16. Radio Jove: Citizen Science for Jupiter Radio Astronomy

    Science.gov (United States)

    Higgins, C. A.; Thieman, J.; Reyes, F. J.; Typinski, D.; Flagg, R. F.; Greenman, W.; Brown, J.; Ashcraft, T.; Sky, J.; Cecconi, B.; Garcia, L. N.

    2016-12-01

    The Radio Jove Project (http://radiojove.gsfc.nasa.gov) has been operating as an educational activity for 18 years to introduce radio astronomy activities to students, teachers, and the general public. Participants may build a simple radio telescope kit, make scientific observations, and interact with radio observatories in real-time over the Internet. Recently some of our dedicated citizen science observers have upgraded their systems to better study radio emission from Jupiter and the Sun by adding dual-polarization spectrographs and wide-band antennas in the frequency range of 15-30 MHz. Some of these observations are being used in conjunction with professional telescopes such as the Long Wavelength Array (LWA), the Nancay Decametric Array, and the Ukrainian URAN2 Radio Telescope. In particular, there is an effort to support the Juno Mission radio waves instrument at Jupiter by using citizen science ground-based data for comparison and polarization verification. These data will be archived through a Virtual European Solar and Planetary Access (VESPA) archive (https://voparis-radiojove.obspm.fr/radiojove/welcome) for use by the amateur and professional radio science community. We overview the program and display recent observations that will be of interest to the science community.

  17. The coexistence of cognitive radio and radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Boonstra, A.J.; Baan, W.A.

    2009-01-01

    An increase of the efficiency of spectrum usage requires the development of new communication techniques. Cognitive radio may be one of those new technique, which uses unoccupied frequency bands for communications. This will lead to more power in the bands and therefore an increasing level of Radio

  18. Evaluation of GNU Radio Platform Enhanced for Hardware Accelerated Radio Design

    OpenAIRE

    Karve, Mrudula Prabhakar

    2010-01-01

    The advent of software radio technology has enabled radio developers to design and imple- ment radios with great ease and flexibility. Software radios are effective in experimentation and development of radio designs. However, they have limitations when it comes to high- speed, high-throughput designs. This limitation can be overcome by introducing a hardware element to the software radio platform. Enhancing GNU Radio for Hardware Accelerated Radio Design project implements suc...

  19. Dramatugi Penyiar Radio

    Directory of Open Access Journals (Sweden)

    Hastika Yanti Nora

    2009-07-01

    Full Text Available Dramaturgy is the work of Erving Goffman. He wrote "Presentation of Self in Everyday Life" in '1959. Following the theatrical analogy, Goffman spoke of a front stage and back stage. The front stage is that part of the performance that generally functions in rather fixed and general ways to define the situation for those who observed the performance. The back stage is situation where facts suppressed in the front or various kinds of informal actions may appear. A back stage is usually adjacent to the front stage, but it also cut off from it. Everyone in this world have to run his role in their everyday life. It also a radio announcer. As an actor, they have to be a nice and friendy person when they perform to make air personality, that is  a good  impression, from their audience. But before their perform in the front stage, there so much to do to prepare in the backstage. The front and back stage is radio announcer dramaturgy.

  20. Radio Frequency (RF) Biomolecules

    Science.gov (United States)

    2005-11-01

    tetramethylrhodamine (TMR, Molecular Probes). Attachment of the TMR to the primary amine on Z was achieved by incubating the molecules together in sodium bicarbonate ...a) Novak, J. P.; Brousseau, L. C., III; Vance, F. W.; Johnson, R. C.; Lemon , B. I.; Hupp, J. T.; Feldheim, D. L. J. Am. Chem. Soc. 2000, 122, 12029

  1. MURCHISON WIDEFIELD ARRAY LIMITS ON RADIO EMISSION FROM ANTARES NEUTRINO EVENTS

    Energy Technology Data Exchange (ETDEWEB)

    Croft, S. [University of California, Berkeley, Astronomy Department, 501 Campbell Hall #3411, Berkeley, CA 94720 (United States); Kaplan, D. L. [Department of Physics, University of Wisconsin-Milwaukee, 1900 East Kenwood Boulevard, Milwaukee, WI 53211 (United States); Tingay, S. J. [International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102 (Australia); Murphy, T.; Rowlinson, A. [ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) (Australia); Bell, M. E. [CSIRO Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710 (Australia); Adrián-Martínez, S.; Ardid, M. [Institut d’Investigació per a la Gestió Integrada de les Zones Costaneres (IGIC)—Universitat Politècnica de València. C/ Paranimf 1, E-46730 Gandia (Spain); Ageron, M.; Aubert, J.-J. [Aix Marseille Université, CNRS/IN2P3, CPPM UMR 7346, F-13288, Marseille (France); Albert, A. [GRPHE—Université de Haute Alsace—Institut universitaire de technologie de Colmar, 34 rue du Grillenbreit BP 50568-68008 Colmar (France); André, M. [Technical University of Catalonia, Laboratory of Applied Bioacoustics, Rambla Exposició, E-08800 Vilanova i la Geltrú, Barcelona (Spain); Anton, G. [Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen Centre for Astroparticle Physics, Erwin-Rommel-Str. 1, D-91058 Erlangen (Germany); Avgitas, T.; Baret, B. [APC, Université Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cité, F-75205 Paris (France); Collaboration: for the MWA Collaboration; for the ANTARES Collaboration; for the TAROT Collaboration; for the ROTSE Collaboration; and others

    2016-04-01

    We present a search, using the Murchison Widefield Array (MWA), for electromagnetic (EM) counterparts to two candidate high-energy neutrino events detected by the ANTARES neutrino telescope in 2013 November and 2014 March. These events were selected by ANTARES because they are consistent, within 0.°4, with the locations of galaxies within 20 Mpc of Earth. Using MWA archival data at frequencies between 118 and 182 MHz, taken ∼20 days prior to, at the same time as, and up to a year after the neutrino triggers, we look for transient or strongly variable radio sources that are consistent with the neutrino positions. No such counterparts are detected, and we set a 5σ upper limit for low-frequency radio emission of ∼10{sup 37} erg s{sup −1} for progenitors at 20 Mpc. If the neutrino sources are instead not in nearby galaxies, but originate in binary neutron star coalescences, our limits place the progenitors at z ≳ 0.2. While it is possible, due to the high background from atmospheric neutrinos, that neither event is astrophysical, the MWA observations are nevertheless among the first to follow up neutrino candidates in the radio, and illustrate the promise of wide-field instruments like MWA for detecting EM counterparts to such events.

  2. CME-Associated Radio Bursts from Satellite Observations

    Science.gov (United States)

    Gopalswamy, Nat

    2012-01-01

    Coronal mass ejections (CMEs) are closely associated with various types of radio bursts from the Sun. All radio bursts are due to nonthermal electrons, which are accelerated during the eruption of CMEs. Radio bursts at frequencies below about 15 MHz are of particular interest because they are associated with energetic CMEs that contribute to severe space weather. The low-frequency bursts need to be observed primarily from space because of the ionospheric cutoff. The main CME-related radio bursts are associated are: type III bursts due to accelerated electrons propagating along open magnetic field lines, type II bursts due to electrons accelerated in shocks, and type IV bursts due to electrons trapped in post-eruption arcades behind CMEs. This paper presents a summary of results obtained during solar cycle 23 primarily using the white-light coronagraphic observations from the Solar Heliospheric Observatory (SOHO) and the WAVES experiment on board Wind. Particular emphasis will be placed on what we can learn about particle acceleration in the coronal and interplanetary medium by analyzing the CMEs and the associated radio bursts.

  3. RADIO NOISE ADVANCES SEXUAL MATURITY

    African Journals Online (AJOL)

    ansistf-lewis

    partially illuminated by the normally non-stimulatory 7-h photoperiod, is another possible reason for the earlier sexual development. Plasma melatonin concentrations midway through the 7-h dark period in which the radio was played were similar to those of non-radio controls, indicating that this period was not regarded.

  4. Tuning in to pavement radio

    NARCIS (Netherlands)

    Ellis, S.D.K.

    1989-01-01

    This article describes a phenomenon known all over Africa, for which there is no really satisfactory term in English but which is summed up in the French term 'radio trottoir', literally 'pavement radio'. It may be defined as the popular and unofficial discussion of current affairs in Africa,

  5. Dust tori in radio galaxies

    NARCIS (Netherlands)

    van der Wolk, G.; Barthel, P. D.; Peletier, R. F.; Pel, J. W.

    Aims. We investigate the quasar - radio galaxy unification scenario and detect dust tori within radio galaxies of various types. Methods. Using VISIR on the VLT, we acquired sub-arcsecond (similar to 0.40 '') resolution N-band images, at a wavelength of 11.85 mu m, of the nuclei of a sample of 27

  6. Radio design in nanometer technologies

    CERN Document Server

    Ismail, Mohammed

    2006-01-01

    This is the first volume that looks at the integrated radio design problem as a "piece of a big puzzle" Most books discuss more on communications or more on hardware but not both, this book strikes the right balance between the two and provides the reader with a holistic view of the subject of radio design: current and future trends.

  7. Cognitive Radio for Emergency Networks

    NARCIS (Netherlands)

    Zhang, Q.; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2006-01-01

    In the scope of the Adaptive Ad-hoc Freeband (AAF) project, an emergency network built on top of Cognitive Radio is proposed to alleviate the spectrum shortage problem which is the major limitation for emergency networks. Cognitive Radio has been proposed as a promising technology to solve

  8. Radio outburst of BL Lacertae

    Science.gov (United States)

    Buemi, C. S.; Leto, P.; Trigilio, C.; Umana, G.; Giroletti, M.; Orienti, M.; Raiteri, C. M.; Villata, M.; Bach, U.

    2013-04-01

    We report on extremely high radio flux of BL Lacertae at 43 and 8 GHz. Observations at 43 GHz with the 32 m radio telescope in Noto (Italy) revealed a flux density of 10.5 +/- 0.2 Jy on 2013 April 10.65, while observations at 8 GHz with the 32 m radio telescope in Medicina (Italy) detected a flux density of 8.2 +/- 0.7 Jy on April 12.22. These extremely high radio fluxes show that the radio activity likely correlated to the strong optical, near-infrared, and gamma-ray activity of 2011-2012 (see ATels #4028, #4031, #4155, #4271, #4277, #4349, #4565, #4600), and X-ray activity of late 2012 (ATels #4557, #4627), is far to be exhausted.

  9. Radio propagation measurement and channel modelling

    CERN Document Server

    Salous, Sana

    2013-01-01

    While there are numerous books describing modern wireless communication systems that contain overviews of radio propagation and radio channel modelling, there are none that contain detailed information on the design, implementation and calibration of radio channel measurement equipment, the planning of experiments and the in depth analysis of measured data. The book would begin with an explanation of the fundamentals of radio wave propagation and progress through a series of topics, including the measurement of radio channel characteristics, radio channel sounders, measurement strategies

  10. Star-Formation in Low Radio Luminosity AGN from the Sloan Digital Sky Survey

    Energy Technology Data Exchange (ETDEWEB)

    de Vries, W H; Hodge, J A; Becker, R H; White, R L; Helfand, D J

    2007-04-18

    We investigate faint radio emission from low- to high-luminosity Active Galactic Nuclei (AGN) selected from the Sloan Digital Sky Survey (SDSS). Their radio properties are inferred by coadding large ensembles of radio image cut-outs from the FIRST survey, as almost all of the sources are individually undetected. We correlate the median radio flux densities against a range of other sample properties, including median values for redshift, [O III] luminosity, emission line ratios, and the strength of the 4000{angstrom} break. We detect a strong trend for sources that are actively undergoing star-formation to have excess radio emission beyond the {approx} 10{sup 28} ergs s{sup -1} Hz{sup -1} level found for sources without any discernible star-formation. Furthermore, this additional radio emission correlates well with the strength of the 4000{angstrom} break in the optical spectrum, and may be used to assess the age of the star-forming component. We examine two subsamples, one containing the systems with emission line ratios most like star-forming systems, and one with the sources that have characteristic AGN ratios. This division also separates the mechanism responsible for the radio emission (star-formation vs. AGN). For both cases we find a strong, almost identical, correlation between [O III] and radio luminosity, with the AGN sample extending toward lower, and the star-formation sample toward higher luminosities. A clearer separation between the two subsamples is seen as function of the central velocity dispersion {sigma} of the host galaxy. For systems at similar redshifts and values of {sigma}, the star-formation subsample is brighter than the AGN in the radio by an order of magnitude. This underlines the notion that the radio emission in star-forming systems can dominate the emission associated with the AGN.

  11. The Radio Language Arts Project: adapting the radio mathematics model.

    Science.gov (United States)

    Christensen, P R

    1985-01-01

    Kenya's Radio Language Arts Project, directed by the Academy for Educational Development in cooperation with the Kenya Institute of Education in 1980-85, sought to teach English to rural school children in grades 1-3 through use of an intensive, radio-based instructional system. Daily 1/2 hour lessons are broadcast throughout the school year and supported by teachers and print materials. The project further was aimed at testing the feasibility of adaptation of the successful Nicaraguan Radio Math Project to a new subject area. Difficulties were encountered in articulating a language curriculum with the precision required for a media-based instructional system. Also a challenge was defining the acceptable regional standard for pronunciation and grammar; British English was finally selected. An important modification of the Radio Math model concerned the role of the teacher. While Radio Math sought to reduce the teacher's responsibilities during the broadcast, Radio Language Arts teachers played an important instructional role during the English lesson broadcasts by providing translation and checks on work. Evaluations of the Radio language Arts Project suggest significant gains in speaking, listening, and reading skills as well as high levels of satisfaction on the part of parents and teachers.

  12. Implementing Software Defined Radio

    CERN Document Server

    Grayver, Eugene

    2013-01-01

    Software Defined Radio makes wireless communications easier, more efficient, and more reliable. This book bridges the gap between academic research and practical implementation. When beginning a project, practicing engineers, technical managers, and graduate students can save countless hours by considering the concepts presented in these pages. The author covers the myriad options and trade-offs available when selecting an appropriate hardware architecture. As demonstrated here, the choice between hardware- and software-centric architecture can mean the difference between meeting an aggressive schedule and bogging down in endless design iterations. Because of the author’s experience overseeing dozens of failed and successful developments, he is able to present many real-life examples. Some of the key concepts covered are: Choosing the right architecture for the market – laboratory, military, or commercial Hardware platforms – FPGAs, GPPs, specialized and hybrid devices Standardization efforts to ens...

  13. AGONIZAN RADIOS MINERAS

    Directory of Open Access Journals (Sweden)

    Raquel Salinas

    2015-01-01

    Full Text Available Se ofrece un amplio análisis sobre la industria electoral, recordando que un candidato a presidente es "un producto para la venta". Se Desmenuzan las estrategias utilizadas en el plebiscito chileno,las elecciones norteamericanas con el NO a BUSH. El Mercadeo Social es una nueva metodología utilizada en proyectos de desarrollo a nivel de campo por ello se hace un esclarecimiento y clarifica el vínculo con la comunicación. Se agrega temas como: Los modelos de recepción de mensajes cuyos marcos conceptuales y metodologías aún no se han adaptado al potencial de esta línea de trabajo.Se analiza la agonía de las radios mineras en Bolivia en la que 42 años de historia y heroísmo se desmoronan.

  14. Japanese radio telescopes

    Science.gov (United States)

    Kawaguchi, Noriyuki

    Japanese principal radio telescopes available for Very Long Baseline Interferometry (VLBI) observations are overviewed, and their characteristics and performances are summarized. Three fixed stations, Usuda, Nobeyama, and Kashima, and one 5-m mobile station use a hydrogen master-frequency standard, while other stations use an ultrastable X'tal oscillator locked to a cesium frequency standard. The 64-m telescope in Usuda developed for tracking satellites of deep-space missions is outlined, as well as the Kashima 34-m telescope covering a frequency range from 300 MHz to 49 GHz with 11 receivers. Attention is given to the Nobeyama 45-m telescope as a major telescope in Japan working in an international mm-VLBI network.

  15. Global Ionosphere Radio Observatory

    Science.gov (United States)

    Galkin, I. A.; Reinisch, B. W.; Huang, X. A.

    2014-12-01

    The Global Ionosphere Radio Observatory (GIRO) comprises a network of ground-based high-frequency vertical sounding sensors, ionosondes, with instrument installations in 27 countries and a central Lowell GIRO Data Center (LGDC) for data acquisition and assimilation, including 46 real-time data streams as of August 2014. The LGDC implemented a suite of technologies for post-processing, modeling, analysis, and dissemination of the acquired and derived data products, including: (1) IRI-based Real-time Assimilative Model, "IRTAM", that builds and publishes every 15-minutes an updated "global weather" map of the peak density and height in the ionosphere, as well as a map of deviations from the classic IRI climate; (2) Global Assimilative Model of Bottomside Ionosphere Timelines (GAMBIT) Database and Explorer holding 15 years worth of IRTAM computed maps at 15 minute cadence;. (3) 17+ million ionograms and matching ionogram-derived records of URSI-standard ionospheric characteristics and vertical profiles of electron density; (4) 10+ million records of the Doppler Skymaps showing spatial distributions over the GIRO locations and plasma drifts; (5) Data and software for Traveling Ionospheric Disturbance (TID) diagnostics; and (6) HR2006 ray tracing software mated to the "realistic" IRTAM ionosphere. In cooperation with the URSI Ionosonde Network Advisory Group (INAG), the LGDC promotes cooperative agreements with the ionosonde observatories of the world to accept and process real-time data of HF radio monitoring of the ionosphere, and to promote a variety of investigations that benefit from the global-scale, prompt, detailed, and accurate descriptions of the ionospheric variability.

  16. Electromagnetic counterparts to gravitational waves from black hole mergers and naked singularities

    CERN Document Server

    Malafarina, Daniele

    2016-01-01

    We consider the question here whether the proposed electromagnetic counterpart of the gravitational wave signals in binary black hole coalescence may be due to the appearance of a `short lived' naked singularity during the merger. We point out that the change in topology that the spacetime undergoes during the merger can cause the appearance of a naked singularity. In case some matter, in the form of a small accretion disk, is present in the surroundings of the black hole system then the emitted luminosity during the merger would allow to distinguish the scenario where the naked singularity forms from the scenario where the horizon exists at all times. In fact the emitted luminosity spectrum would be much higher in the case where a naked singularity forms as opposed to the `pure' black hole case. We suggest that the presence of such a transient naked singularity will explain the high luminosity of an electromagnetic counterpart during the merger much more easily.

  17. THE RADIO JET ASSOCIATED WITH THE MULTIPLE V380 ORI SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Luis F.; Yam, J. Omar; Carrasco-González, Carlos [Instituto de Radioastronomía y Astrofísica, UNAM, Apdo. Postal 3-72 (Xangari), 58089 Morelia, Michoacán, México (Mexico); Anglada, Guillem [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía, s/n, E-18008, Granada (Spain); Trejo, Alfonso, E-mail: l.rodriguez@crya.unam.mx [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

    2016-10-01

    The giant Herbig–Haro object 222 extends over ∼6′ in the plane of the sky, with a bow shock morphology. The identification of its exciting source has remained uncertain over the years. A non-thermal radio source located at the core of the shock structure was proposed to be the exciting source. However, Very Large Array studies showed that the radio source has a clear morphology of radio galaxy and a lack of flux variations or proper motions, favoring an extragalactic origin. Recently, an optical–IR study proposed that this giant HH object is driven by the multiple stellar system V380 Ori, located about 23′ to the SE of HH 222. The exciting sources of HH systems are usually detected as weak free–free emitters at centimeter wavelengths. Here, we report the detection of an elongated radio source associated with the Herbig Be star or with its close infrared companion in the multiple V380 Ori system. This radio source has the characteristics of a thermal radio jet and is aligned with the direction of the giant outflow defined by HH 222 and its suggested counterpart to the SE, HH 1041. We propose that this radio jet traces the origin of the large scale HH outflow. Assuming that the jet arises from the Herbig Be star, the radio luminosity is a few times smaller than the value expected from the radio–bolometric correlation for radio jets, confirming that this is a more evolved object than those used to establish the correlation.

  18. A census of radio-selected AGNs on the COSMOS field and of their FIR properties

    Science.gov (United States)

    Magliocchetti, M.; Popesso, P.; Brusa, M.; Salvato, M.

    2018-01-01

    We use the new catalogue by Laigle et al. to provide a full census of VLA-COSMOS radio sources. We identify 90 per cent of such sources and sub-divide them into active galactic nuclei (AGNs) and star-forming galaxies on the basis of their radio luminosity. The AGN sample is complete with respect to radio selection at all z ≲ 3.5. Out of 704 AGNs, 272 have a counterpart in the Herschel maps. By exploiting the better statistics of the new sample, we confirm the results of Magliocchetti et al.: the probability for a radio-selected AGN to be detected at far-infrared (FIR) wavelengths is both a function of radio luminosity and redshift, whereby powerful sources are more likely FIR emitters at earlier epochs. Such an emission is due to star-forming processes within the host galaxy. FIR emitters and non-FIR emitters only differentiate in the z ≲ 1 universe. At higher redshifts, they are indistinguishable from each other, as there is no difference between FIR-emitting AGNs and star-forming galaxies. Lastly, we focus on radio AGNs which show AGN emission at other wavelengths. We find that mid-infrared (MIR) emission is mainly associated with ongoing star formation and with sources which are smaller, younger and more radio luminous than the average parent population. X-ray emitters instead preferentially appear in more massive and older galaxies. We can therefore envisage an evolutionary track whereby the first phase of a radio-active AGN and of its host galaxy is associated with MIR emission, while at later stages the source becomes only active at radio wavelengths and possibly also in the X-ray.

  19. Radio-weak BL Lac Objects in the Fermi Era

    Science.gov (United States)

    Massaro, F.; Marchesini, E. J.; D'Abrusco, R.; Masetti, N.; Andruchow, I.; Smith, Howard A.

    2017-01-01

    The existence of “radio-weak BL Lac objects” (RWBLs) has been an open question, and has remained unsolved since the discovery that quasars could be radio-quiet or radio-loud. Recently, several groups identified RWBL candidates, mostly found while searching for low-energy counterparts of the unidentified or unassociated gamma-ray sources listed in the Fermi catalogs. Confirming RWBLs is a challenging task since they could be confused with white dwarfs (WDs) or weak emission line quasars (WELQs) when there are not sufficient data to precisely draw their broadband spectral energy distribution, and their classification is mainly based on a featureless optical spectra. Motivated by the recent discovery that Fermi BL Lacs appear to have very peculiar mid-IR emission, we show that it is possible to distinguish between WDs, WELQs, and BL Lacs using the [3.4]-[4.6]-[12] μm color-color plot built using the WISE magnitudes when the optical spectrum is available. On the basis of this analysis, we identify WISE J064459.38+603131 and WISE J141046.00+740511.2 as the first two genuine RWBLs, both potentially associated with Fermi sources. Finally, to strengthen our identification of these objects as true RWBLs, we present multifrequency observations for these two candidates to show that their spectral behavior is indeed consistent with that of the BL Lac population.

  20. RADIO-WEAK BL LAC OBJECTS IN THE FERMI ERA

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F.; Marchesini, E. J. [Dipartimento di Fisica, Università degli Studi di Torino (UniTO), via Pietro Giuria 1, I-10125 Torino (Italy); D’Abrusco, R.; Smith, Howard A. [Smithsonian Astrophysical Observatory, 60 Garden Street, 02138 Cambridge, MA (United States); Masetti, N. [INAF—Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, via Gobetti 101, I-40129, Bologna (Italy); Andruchow, I. [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque, B1900FWA, La Plata (Argentina)

    2017-01-10

    The existence of “radio-weak BL Lac objects” (RWBLs) has been an open question, and has remained unsolved since the discovery that quasars could be radio-quiet or radio-loud. Recently, several groups identified RWBL candidates, mostly found while searching for low-energy counterparts of the unidentified or unassociated gamma-ray sources listed in the Fermi catalogs. Confirming RWBLs is a challenging task since they could be confused with white dwarfs (WDs) or weak emission line quasars (WELQs) when there are not sufficient data to precisely draw their broadband spectral energy distribution, and their classification is mainly based on a featureless optical spectra. Motivated by the recent discovery that Fermi BL Lacs appear to have very peculiar mid-IR emission, we show that it is possible to distinguish between WDs, WELQs, and BL Lacs using the [3.4]–[4.6]–[12] μ m color–color plot built using the WISE magnitudes when the optical spectrum is available. On the basis of this analysis, we identify WISE J064459.38+603131 and WISE J141046.00+740511.2 as the first two genuine RWBLs, both potentially associated with Fermi sources. Finally, to strengthen our identification of these objects as true RWBLs, we present multifrequency observations for these two candidates to show that their spectral behavior is indeed consistent with that of the BL Lac population.

  1. A comparative study between South African serial killers and their American counterparts

    OpenAIRE

    2009-01-01

    M.A. This dissertation explores the similarities and differences between South African serial killers and their American counterparts. Seven male candidates, each having committed their reign of terror within the relevant time period, have been included. The candidates compared well in home environments, number of friendships, emotional maturity, abuse undergone, temperament, and anti-social behaviour. Differences were found in comparing family bonding, wealth and education. This dissertat...

  2. Postprandial hypoglycemic effect of mulberry leaf in Goto-Kakizaki rats and counterpart control Wistar rats

    OpenAIRE

    Park, Ji Min; Bong, Ha Yoon; Jeong, Hye In; Kim, Yeon Kyoung; Kim, Ji Yeon; Kwon, Oran

    2009-01-01

    Postprandial hypoglycemic effect of mulberry leaf (Morus alba L.) was compared in two animal models: Goto-Kakizaki (GK) rats, a spontaneous non-obese animal model for type II diabetes, and their counterpart control Wistar rats. First, the effect of a single oral administration of mulberry leaf aqueous extract (MLE) on postprandial glucose responses was determined using maltose or glucose as substrate. With maltose-loading, MLE reduced peak responses of blood glucose significantly in both GK a...

  3. Cassini and Galileo Observations of Quasi-periodic Radio Bursts

    Science.gov (United States)

    Hospodarsky, G. B.; Kurth, W. S.; Gurnett, D. A.; Kaiser, M. L.; Zarka, P.; Krupp, N.; Waite, J. H.

    Simultaneous measurements of many Jovian plasma and radio emissions were ob- tained by the Cassini and Galileo spacecraft during the Cassini flyby of Jupiter (clos- est approach was on December 30, 2000). Jovian type III radio emissions, also known as quasi-periodic (QP) emissions, were often detected by both spacecraft. This type of emission has been detected by Voyager, Ulysses, Galileo, and Cassini, with pe- riodicities ranging from about a minute to many tens of minutes (often around 40 minutes). Other quasi-periodic events have been detected in the energetic particle data of Ulysses, Galileo and Cassini and in the x-ray spectrum obtained by the Chandra spacecraft, usually with periodicities around 40 minutes. The multiple observations of similar quasi-periodic events suggests that there may be a common source for these phenomena. Many examples of simultaneous detection of the QP radio emissions were obtained by the Cassini and Galileo plasma wave and radio instruments. The charac- teristics of the QP emissions observed by each spacecraft are very similar, and when the difference in the travel time of a radio emission from Jupiter to each spacecraft is taken into account, the QP bursts are observed to occur simultaneously at each space- craft. These similar characteristics of the emissions, even when the two spacecraft are separated by many hours in local time and many degrees of system III longitude, sug- gest a broadly beamed 'strobe light' source for the emission, and not a narrow beam which rotates with the planet. The implications of these simultaneous observations will be discussed.

  4. RadioBOT: A spatial cognitive radio testbed

    Science.gov (United States)

    Beck, Brian M.; Kim, Joseph H.; Baxley, Robert J.; Walkenhorst, Brett T.

    This paper introduces RadioBOT, a flexible system of mobile robots for acquisition of radio frequency data. The motivation for such a test system is described, namely the difficulty in acquiring real world data for the purpose of spatial cognitive radio (CR) research. Some current areas of CR research are presented for which RadioBOT can gather data. We then describe the hardware and software components of our system. As a demonstration of the system's capability, we present here the results of a spectrum mapping experiment. In this experiment, we uniformly sample average signal power in a laboratory hallway where an emitter is present. From this data, we form an interpolated spectrum map of the signal power as a function of space. Knowledge of the area's spectrum map is then used to optimize the relay channel communication rate between a transmitter and receiver, by optimally positioning the relay node.

  5. Foundations for radio frequency engineering

    CERN Document Server

    Geyi, Wen

    2015-01-01

    The book provides a comprehensive coverage of the fundamental topics in microwave engineering, antennas and wave propagation, and electromagnetic compatibility, including electromagnetic boundary value problems, waveguide theory, microwave resonators, antennas and wave propagation, microwave circuits, principles of electromagnetic compatibility designs, information theory and systems. Deals systematically with fundamental problems in radio frequency engineering, this important volume provides an updated treatment of radio frequency theory and techniques. The book can be used as a one-semester course for senior and first-year graduate students or as a reference for radio frequency engineers and applied physicists.

  6. La radio en el ciberespacio

    Directory of Open Access Journals (Sweden)

    Ricardo Horvath

    2015-01-01

    Full Text Available Mientras la radio comunitaria se esfuerza por sobrevivir ante la carencia de leyes de radiodifusión que la protejan, sin fondos económicos ni posibilidades ciertas de expansión, la sofisticada radio digital por satélite (DAB ya es un hecho. Su presencia en el ciberespacio permitirá a los grupos multinacionales difundir sus productos culturales a escala mundial, con calidad de CD, y liquidar las programaciones locales. En este contexto, el reto de la radio democrática se multiplica y complica.

  7. DID INSTAGRAM KILLED THE MYSTERY OF RADIO? USE OF INSTAGRAM IN TURKISH RADIO STATIONS AND RADIO HOSTS

    Directory of Open Access Journals (Sweden)

    Michalis Kuyucu

    2016-04-01

    Full Text Available Turning voice into imagination, radio translated imagination into reality with social media. The radio audience imagined there were people inside the receiver and wondered what kind of people those people were. This convergence between radio and the new media ensured realization of this imagination. The new media established communication between the people inside that radio receiver and the audience. Social media platform Instagram is the latest step in turning the radio from an image into reality. Are radio stations revealing themselves by throwing away the mystery via Instagram or do they still remain mysterious? The purpose of this study is to carry out a research directed at Instagram use of radio stations in Turkey and makes observations with regards to the existence of radio medium in Instagram. The existence of ten Turkish radio stations with the highest ratings among radio stations and ten radio hosts in Instagram was studied within this scope. The messages shared by the radio stations and hosts on their Instagram accounts were examined and an analysis was made intended at use of Instagram through these messages. The Instagram account activities of radio stations between 01 June – 31 December 2015 were reviewed within this scope and Instagram’s contribution to public relations activities of radio stations carried out by social media was scrutinized. The question “Did Instagram unveiled the mystery of radio?” was discussed and how radio is revealed by means of Instagram was underlined in this study.

  8. Radio channel measurement and modelling for future mobile radio systems

    Science.gov (United States)

    Guerdenli, E.; Huish, P. W.

    1989-12-01

    Digital mobile radio systems will require planning methods that provide accurate predictions of signal strength, distortion, and interference for situations ranging from very small cells in dense urban locations to large rural cells. Topographic and land usage data bases will find increasing use to enhance the accuracy of prediction models. The implications of these issues are discussed and the work in progress at British Telecommunications Research Laboratories on land mobile radio propagation modeling and wide-band channel measurements is presented.

  9. Radio frequency integrated circuit design for cognitive radio systems

    CERN Document Server

    Fahim, Amr

    2015-01-01

    This book fills a disconnect in the literature between Cognitive Radio systems and a detailed account of the circuit implementation and architectures required to implement such systems.  Throughout the book, requirements and constraints imposed by cognitive radio systems are emphasized when discussing the circuit implementation details.  In addition, this book details several novel concepts that advance state-of-the-art cognitive radio systems.  This is a valuable reference for anybody with background in analog and radio frequency (RF) integrated circuit design, needing to learn more about integrated circuits requirements and implementation for cognitive radio systems. ·         Describes in detail cognitive radio systems, as well as the circuit implementation and architectures required to implement them; ·         Serves as an excellent reference to state-of-the-art wideband transceiver design; ·         Emphasizes practical requirements and constraints imposed by cognitive radi...

  10. Antithrombin III blood test

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003661.htm Antithrombin III blood test To use the sharing features on this page, ... a protein that helps control blood clotting. A blood test can determine the amount of AT III present ...

  11. On the Harmonic Coupling of Components in Pairs of IIIb-III Bursts at Decameter Wavelengths

    Science.gov (United States)

    Brazhenko, A. I.; Melnik, V. N.; Frantsuzenko, A. V.; Dorovskyy, V. V.; Rucker, H. O.; Panchenko, M.

    2015-06-01

    The properties of IIIb-III pairs observed by the URAN-2 radioThe properties of IIIb-III pairs observed by the URAN-2 radiotelescope at frequencies 16-32 MHz are analyzed. Observations of these bursts were hold in April, June and September 2011. Durations, frequency drift rates, simultaneous frequency ratio of pairs components and their polarizations are analyzed. Pro and contra of IIIb-III harmonic connection are discussed.

  12. Reconfigurable, Digital EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The nature of human exploration missions to the Moon and Mars demands a frequency-agile, reconfigurable, durable digital radio delivering telemetry, ranging, voice,...

  13. Radio Wave Propagation in Tunnels

    National Research Council Canada - National Science Library

    Lee, Jeho

    2000-01-01

    This report examines the radio propagation model for narrow and long tunnels. Modal analysis is used to model the path gain in 2-D and 3-D rectangular tunnels and the coupling loss of L, T and cross tunnels...

  14. Reconfigurable, Digital EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — AeroAstro proposes to develop a low-power, low-volume and lightweight, state-of-the-art digital radio capable of operating in a wide variety of bands, from VHF...

  15. Miniaturized Digital EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Bennett Aerospace and Team Partners propose to develop a small, lightweight, and very power-efficient mobile radio for use on the Lunar surface. Our Team will...

  16. Sea Turtle Radio Telemetry Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Radio transmitters attached to sea turtles captured in various fishing gear enabled us to track and measure surfacing time of each turtle. Determining location of...

  17. Innovativeness and the Public Radio Audience.

    Science.gov (United States)

    Williams, Wenmouth, Jr.; Krugman, Dean M.

    1981-01-01

    A public radio audience was surveyed to test the hypothesis that a relationship exists between innovativeness and public radio listening. Rather than supporting the hypothesis, findings indicate that the entertainment and information elements of public radio are the primary attractions for the public radio audience. (MER)

  18. On the evaluation of Web Radio

    NARCIS (Netherlands)

    Field, A.N.; Hartel, Pieter H.

    We develop an evaluation method for Web radio, and perform it to see what we can be learnt about seven prominent Web radio sites. We also evaluate a commercial FM radio station for control purposes. We present a taxonomy of Web radio, and we give our observations and conclusions on this evaluation.

  19. Ecuador: Construyendo radio y pueblo

    OpenAIRE

    Teodoro Galarza

    2015-01-01

    En el Ecuador a diferencia de Argentina y Colombia, las radios populares crecen a ritmo lento. En la década pasada hubo estancamiento, pero en los años 90 hay un resurgir de estos medios, con nuevos estilos de trabajo. La coordinadora de radios Populares y Educativas del Ecuador, CORAPE, sigue de cerca esta evolución. El texto trata de la capacitación profesional.

  20. Radio and line transmission 2

    CERN Document Server

    Roddy, Dermot

    2013-01-01

    Radio and Line Transmission, Volume 2 gives a detailed treatment of the subject as well as an introduction to additional advanced subject matter. Organized into 14 chapters, this book begins by explaining the radio wave propagation, signal frequencies, and bandwidth. Subsequent chapters describe the transmission lines and cables; the aerials; tuned and coupled circuits; bipolar transistor amplifiers; field-effect transistors and circuits; thermionic valve amplifiers; LC oscillators; the diode detectors and modulators; and the superheterodyne receiver. Other chapters explore noise and interfere

  1. Interoperability: Stop Blaming the Radio

    Science.gov (United States)

    2007-02-01

    Interoperability: Stop Blaming the Radio Ronald P. Timmons INTRODUCTION One of the most pressing first responder issues emerging in the post-9...00-00-2007 4. TITLE AND SUBTITLE Interoperability: Stop Blaming the Radio 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...recording of a reporter describing the crash of the Hindenburg (“oh, the humanity!”) can attest, stress causes the human voice to take on a very

  2. Ecuador: Construyendo radio y pueblo

    Directory of Open Access Journals (Sweden)

    Teodoro Galarza

    2015-01-01

    Full Text Available En el Ecuador a diferencia de Argentina y Colombia, las radios populares crecen a ritmo lento. En la década pasada hubo estancamiento, pero en los años 90 hay un resurgir de estos medios, con nuevos estilos de trabajo. La coordinadora de radios Populares y Educativas del Ecuador, CORAPE, sigue de cerca esta evolución. El texto trata de la capacitación profesional.

  3. Automatic radio-transmission monitor

    Science.gov (United States)

    Bernstein, A. J.

    1978-01-01

    System continuously monitors radio transmissions stored in memory. If spectrum deviates beyond present limits, alarm is tripped and spectrum is transferred to long-term storage for later analysis. Monitor can be useful in ensuring proper power level and spectral quality and in finding cause of failure. It might also be used to monitor radio-frequency interference or power levels of citizen's-band transmitters.

  4. SPITZER MID-IR SPECTROSCOPY OF POWERFUL 2 JY AND 3CRR RADIO GALAXIES. I. EVIDENCE AGAINST A STRONG STARBURST-AGN CONNECTION IN RADIO-LOUD AGN

    Energy Technology Data Exchange (ETDEWEB)

    Dicken, D.; Axon, D.; Robinson, A.; Kharb, P. [Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States); Tadhunter, C.; Ramos Almeida, C. [Department of Physics and Astronomy University of Sheffield, Hounsfield Road, Sheffield, S3 7RH (United Kingdom); Morganti, R. [ASTRON, P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Kouwenhoven, M. B. N. [Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Haidian Qu, Beijing 100871 (China); Spoon, H. [224 Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States); Inskip, K. J. [Max Planck Institute for Astronomy, Koenigstuhl 17, 69117 Heidelberg (Germany); Holt, J. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Nesvadba, N. P. H., E-mail: daniel.dicken@ias.u-psud.fr [Institut d' Astrophysique Spatiale, CNRS, Universite Paris Sud, 91405 Orsay (France)

    2012-02-01

    We present deep Spitzer/Infrared Spectrograph (IRS) spectra for complete samples of 46 2 Jy radio galaxies (0.05 < z < 0.7) and 19 3CRR FRII radio galaxies (z < 0.1), and use the detection of polycyclic aromatic hydrocarbon (PAH) features to examine the incidence of contemporaneous star formation and radio-loud active galactic nucleus (AGN) activity. Our analysis reveals PAH features in only a minority (30%) of the objects with good IRS spectra. Using the wealth of complementary data available for the 2 Jy and 3CRR samples we make detailed comparisons between a range of star formation diagnostics: optical continuum spectroscopy, mid- to far-IR (MFIR) color, far-IR excess and PAH detection. There is good agreement between the various diagnostic techniques: most candidates identified to have star formation activity on the basis of PAH detection are also identified using at least two of the other techniques. We find that only 35% of the combined 2 Jy and 3CRR sample show evidence for recent star formation activity (RSFA) at optical and/or MFIR wavelengths. This result argues strongly against the idea of a close link between starburst and powerful radio-loud AGN activity, reinforcing the view that, although a large fraction of powerful radio galaxies may be triggered in galaxy interactions, only a minority are triggered at the peaks of star formation activity in major, gas-rich mergers. However, we find that compact radio sources (D < 15 kpc) show a significantly higher incidence of RSFA (>75%) than their more extended counterparts ( Almost-Equal-To 15%-25%). We discuss this result in the context of a possible bias toward the selection of compact radio sources triggered in gas-rich environments.

  5. A zero-power radio receiver.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2004-09-01

    This report describes both a general methodology and some specific examples of passive radio receivers. A passive radio receiver uses no direct electrical power but makes sole use of the power available in the radio spectrum. These radio receivers are suitable as low data-rate receivers or passive alerting devices for standard, high power radio receivers. Some zero-power radio architectures exhibit significant improvements in range with the addition of very low power amplifiers or signal processing electronics. These ultra-low power radios are also discussed and compared to the purely zero-power approaches.

  6. Multiwavelength detectability of Pop III GRBs from afterglow simulations

    Science.gov (United States)

    Macpherson, D.; Coward, D.

    2017-05-01

    Afterglows of gamma-ray bursts (GRBs) from Population III (Pop III) stars could reveal the formation history and properties of these first generation stars. Through detailed simulation, we predict the prospects of detecting these afterglows with a range of established, existing and upcoming telescopes across the spectrum from radio waves to X-rays. The simulations show that the afterglow light curves of Pop III GRBs at high redshift (≳8) are very similar to those of Pop I/II GRBs at lower redshift (˜2), with the distinction that Lyα absorption at Pop III redshifts removes any optical [and some near-infrared (NIR)] component. We calculate that within a single field of view (FOV) of the Australian Square Kilometre Array Pathfinder (ASKAP) telescope there will be on average four detectable Pop III GRB afterglows. This is the product of ASKAP's large FOV and excellent sensitivity at wavelengths where the afterglows are very long-lasting. We show that the exceptional sensitivity of the James Webb Space Telescope (JWST) Near-InfraRed Camera will make this the optimal instrument for afterglow follow-up and redshift measurement, while JWST Near-InfraRed Spectrograph will be able to detect the absorption features of Pop III-enriched environments in 70 per cent of directed Pop III GRB afterglows. We also find that the Atacama Large Millimetre Array is very poorly suited to observe these afterglows, and that the Spectrum-Roentgen-Gamma 4 yr all-sky X-ray survey has a 12 per cent chance of detecting an orphan Pop III GRB afterglow. The optimal strategy for detecting, identifying and studying Pop III GRB afterglows is to have JWST attempt NIR photometry of afterglows with a detected radio component but no detected optical component.

  7. RADIO WITHOUT A LISTENER: "MAYAK"

    Directory of Open Access Journals (Sweden)

    Bysko Maxim V.

    2017-12-01

    Full Text Available The singularity of this article is that it is entirely based on a critical analysis of only one live musical radio program on the Mayak radio station and dedicated to the life and work of the famous British composer Andrew Lloyd Webber. In principle, the article can be considered a scientific review of the media product. Based on his analysis, the author comes to the paradoxical conclusion that the presence of a listener becomes unnecessary for modern broadcasting. This is stated by many principles of the conduct of the air, presented in the radio program, where all the information load is placed on the guest in the studio, where there is no preparatory work of the DJs, where their inability to navigate the genres of journalism violates communication norms and colloquial ethics, where an obvious deconstructive approach to the material offered for the listener. In addition, the phenomenon of being the DJs in the radio studio exclusively "for themselves" is emphasized by the sound design of the radio program, which runs counter to the logic of auditory perception (for example, the sequence of jingles, as well as the incompetent selection of musical material, which undoubtedly repels professional radio listeners-musicians.

  8. Hunting Electromagnetic Counterparts of Gravitational-wave Events Using the Zwicky Transient Facility

    Science.gov (United States)

    Ghosh, Shaon; Chatterjee, Deep; Kaplan, David L.; Brady, Patrick R.; Van Sistine, Angela

    2017-11-01

    Detections of coalescing binary black holes by LIGO have opened a new window of transient astronomy. With increasing sensitivity of LIGO and participation of the Virgo detector in Cascina, Italy, we expect to soon detect coalescence of compact binary systems with one or more neutron stars. These are the prime targets for electromagnetic follow-up of gravitational wave triggers, which holds enormous promise of rich science. However, hunting for electromagnetic counterparts of gravitational wave events is a non-trivial task due to the sheer size of the error regions, which could span hundreds of square degrees. This may require deep observation with large field-of-view telescopes and/or use of galaxy catalogs. The Zwicky Transient facility (ZTF), scheduled to begin operation in 2017, is designed to cover such large sky-localization areas. In this work, we present the strategies of efficiently tiling the sky to facilitate the observation of the gravitational wave error regions using ZTF. To do this, we used simulations consisting of 475 binary neutron star coalescences detected using a mix of two- and three-detector networks. Our studies reveal that, using two overlapping sets of ZTF tiles and a (modified) ranked-tiling algorithm, we can cover the gravitational-wave sky-localization regions with half as many pointings as a simple contour-covering algorithm. We then incorporated the ranked-tiling strategy to study our ability to observe the counterparts. This requires optimization of observation depth and localization area coverage. Our results show that observation in r-band with ˜600 seconds of integration time per pointing seems to be optimum for typical assumed brightnesses of electromagnetic counterparts, if we plan to spend equal amount of time per pointing. However, our results also reveal that we can gain by as much as 50% in detection efficiency if we linearly scale our integration time per pointing based on the tile probability.

  9. Hunting Electromagnetic Counterparts of Gravitational-wave Events Using the Zwicky Transient Facility

    Science.gov (United States)

    Ghosh, Shaon; Chatterjee, Deep; Kaplan, David L.; Brady, Patrick R.; Van Sistine, Angela

    2017-11-01

    Detections of coalescing binary black holes by LIGO have opened a new window of transient astronomy. With increasing sensitivity of LIGO and participation of the Virgo detector in Cascina, Italy, we expect to soon detect coalescence of compact binary systems with one or more neutron stars. These are the prime targets for electromagnetic follow-up of gravitational wave triggers, which holds enormous promise of rich science. However, hunting for electromagnetic counterparts of gravitational wave events is a non-trivial task due to the sheer size of the error regions, which could span hundreds of square degrees. This may require deep observation with large field-of-view telescopes and/or use of galaxy catalogs. The Zwicky Transient facility (ZTF), scheduled to begin operation in 2017, is designed to cover such large sky-localization areas. In this work, we present the strategies of efficiently tiling the sky to facilitate the observation of the gravitational wave error regions using ZTF. To do this, we used simulations consisting of 475 binary neutron star coalescences detected using a mix of two- and three-detector networks. Our studies reveal that, using two overlapping sets of ZTF tiles and a (modified) ranked-tiling algorithm, we can cover the gravitational-wave sky-localization regions with half as many pointings as a simple contour-covering algorithm. We then incorporated the ranked-tiling strategy to study our ability to observe the counterparts. This requires optimization of observation depth and localization area coverage. Our results show that observation in r-band with ∼600 seconds of integration time per pointing seems to be optimum for typical assumed brightnesses of electromagnetic counterparts, if we plan to spend equal amount of time per pointing. However, our results also reveal that we can gain by as much as 50% in detection efficiency if we linearly scale our integration time per pointing based on the tile probability.

  10. Energy metabolism in human pluripotent stem cells and their differentiated counterparts.

    Directory of Open Access Journals (Sweden)

    Sandra Varum

    Full Text Available Human pluripotent stem cells have the ability to generate all cell types present in the adult organism, therefore harboring great potential for the in vitro study of differentiation and for the development of cell-based therapies. Nonetheless their use may prove challenging as incomplete differentiation of these cells might lead to tumoregenicity. Interestingly, many cancer types have been reported to display metabolic modifications with features that might be similar to stem cells. Understanding the metabolic properties of human pluripotent stem cells when compared to their differentiated counterparts can thus be of crucial importance. Furthermore recent data has stressed distinct features of different human pluripotent cells lines, namely when comparing embryo-derived human embryonic stem cells (hESCs and induced pluripotent stem cells (IPSCs reprogrammed from somatic cells.We compared the energy metabolism of hESCs, IPSCs, and their somatic counterparts. Focusing on mitochondria, we tracked organelle localization and morphology. Furthermore we performed gene expression analysis of several pathways related to the glucose metabolism, including glycolysis, the pentose phosphate pathway and the tricarboxylic acid (TCA cycle. In addition we determined oxygen consumption rates (OCR using a metabolic extracellular flux analyzer, as well as total intracellular ATP levels by high performance liquid chromatography (HPLC. Finally we explored the expression of key proteins involved in the regulation of glucose metabolism.Our results demonstrate that, although the metabolic signature of IPSCs is not identical to that of hESCs, nonetheless they cluster with hESCs rather than with their somatic counterparts. ATP levels, lactate production and OCR revealed that human pluripotent cells rely mostly on glycolysis to meet their energy demands. Furthermore, our work points to some of the strategies which human pluripotent stem cells may use to maintain high

  11. Automated cross-identifying radio to infrared surveys using the LRPY algorithm: a case study

    Science.gov (United States)

    Weston, S. D.; Seymour, N.; Gulyaev, S.; Norris, R. P.; Banfield, J.; Vaccari, M.; Hopkins, A. M.; Franzen, T. M. O.

    2018-02-01

    Cross-identifying complex radio sources with optical or infra red (IR) counterparts in surveys such as the Australia Telescope Large Area Survey (ATLAS) has traditionally been performed manually. However, with new surveys from the Australian Square Kilometre Array Pathfinder detecting many tens of millions of radio sources, such an approach is no longer feasible. This paper presents new software (LRPY - Likelihood Ratio in PYTHON) to automate the process of cross-identifying radio sources with catalogues at other wavelengths. LRPY implements the likelihood ratio (LR) technique with a modification to account for two galaxies contributing to a sole measured radio component. We demonstrate LRPY by applying it to ATLAS DR3 and a Spitzer-based multiwavelength fusion catalogue, identifying 3848 matched sources via our LR-based selection criteria. A subset of 1987 sources have flux density values for all IRAC bands which allow us to use criteria to distinguish between active galactic nuclei (AGNs) and star-forming galaxies (SFG). We find that 936 radio sources ( ≈ 47 per cent) meet both of the Lacy and Stern AGN selection criteria. Of the matched sources, 295 have spectroscopic redshifts and we examine the radio to IR flux ratio versus redshift, proposing an AGN selection criterion below the Elvis radio-loud AGN limit for this dataset. Taking the union of all three AGNs selection criteria we identify 956 as AGNs ( ≈ 48 per cent). From this dataset, we find a decreasing fraction of AGNs with lower radio flux densities consistent with other results in the literature.

  12. The radio properties of infrared-faint radio sources

    Science.gov (United States)

    Middelberg, E.; Norris, R. P.; Hales, C. A.; Seymour, N.; Johnston-Hollitt, M.; Huynh, M. T.; Lenc, E.; Mao, M. Y.

    2011-02-01

    Context. Infrared-faint radio sources (IFRS) are objects that have flux densities of several mJy at 1.4 GHz, but that are invisible at 3.6 μm when using sensitive Spitzer observations with μJy sensitivities. Their nature is unclear and difficult to investigate since they are only visible in the radio. Aims: High-resolution radio images and comprehensive spectral coverage can yield constraints on the emission mechanisms of IFRS and can give hints to similarities with known objects. Methods: We imaged a sample of 17 IFRS at 4.8 GHz and 8.6 GHz with the Australia Telescope Compact Array to determine the structures on arcsecond scales. We added radio data from other observing projects and from the literature to obtain broad-band radio spectra. Results: We find that the sources in our sample are either resolved out at the higher frequencies or are compact at resolutions of a few arcsec, which implies that they are smaller than a typical galaxy. The spectra of IFRS are remarkably steep, with a median spectral index of -1.4 and a prominent lack of spectral indices larger than -0.7. We also find that, given the IR non-detections, the ratio of 1.4 GHz flux density to 3.6 μm flux density is very high, and this puts them into the same regime as high-redshift radio galaxies. Conclusions: The evidence that IFRS are predominantly high-redshift sources driven by active galactic nuclei (AGN) is strong, even though not all IFRS may be caused by the same phenomenon. Compared to the rare and painstakingly collected high-redshift radio galaxies, IFRS appear to be much more abundant, but less luminous, AGN-driven galaxies at similar cosmological distances.

  13. Information Content in Radio Waves: Student Investigations in Radio Science

    Science.gov (United States)

    Jacobs, K.; Scaduto, T.

    2013-12-01

    We describe an inquiry-based instructional unit on information content in radio waves, created in the summer of 2013 as part of a MIT Haystack Observatory (Westford, MA) NSF Research Experiences for Teachers (RET) program. This topic is current and highly relevant, addressing science and technical aspects from radio astronomy, geodesy, and atmospheric research areas as well as Next Generation Science Standards (NGSS). Projects and activities range from simple classroom demonstrations and group investigations, to long term research projects incorporating data acquisition from both student-built instrumentation as well as online databases. Each of the core lessons is applied to one of the primary research centers at Haystack through an inquiry project that builds on previously developed units through the MIT Haystack RET program. In radio astronomy, students investigate the application of a simple and inexpensive software defined radio chip (RTL-SDR) for use in systems implementing a small and very small radio telescope (SRT and VSRT). Both of these systems allow students to explore fundamental principles of radio waves and interferometry as applied to radio astronomy. In ionospheric research, students track solar storms from the initial coronal mass ejection (using Solar Dynamics Observatory images) to the resulting variability in total electron density concentrations using data from the community standard Madrigal distributed database system maintained by MIT Haystack. Finally, students get to explore very long-baseline interferometry as it is used in geodetic studies by measuring crustal plate displacements over time. Alignment to NextGen standards is provided for each lesson and activity with emphasis on HS-PS4 'Waves and Their Applications in Technologies for Information Transfer'.

  14. Radio Frequency Interference Site Survey for Thai Radio Telescopes

    Science.gov (United States)

    Jaroenjittichai, P.; Punyawarin, S.; Singwong, D.; Somboonpon, P.; Prasert, N.; Bandudej, K.; Kempet, P.; Leckngam, A.; Poshyachinda, S.; Soonthornthum, B.; Kramer, B.

    2017-09-01

    Radio astronomical observations have increasingly been threaten by the march of today telecommunication and wireless technology. Performance of radio telescopes lies within the fact that astronomical sources are extremely weak. National Astronomy Research Institute of Thailand (NARIT) has initiated a 5-year project, known as the Radio Astronomy Network and Geodesy for Development (RANGD), which includes the establishment of 40-meter and 13-meter radio telescopes. Possible locations have been narrowed down to three candidates, situated in the Northern part of Thailand, where the atmosphere is sufficiently dry and suitable for 22 and 43 GHz observations. The Radio Frequency Interference (RFI) measurements were carried out with a DC spectrum analyzer and directional antennas at 1.5 meter above ground, from 20 MHz to 6 GHz with full azimuth coverage. The data from a 3-minute pointing were recorded for both horizontal and vertical polarizations, in maxhold and average modes. The results, for which we used to make preliminary site selection, show signals from typical broadcast and telecommunication services and aeronautics applications. The signal intensity varies accordingly to the presence of nearby population and topography of the region.

  15. Near-infrared counterparts of three transient very faint neutron star X-ray binaries

    Science.gov (United States)

    Shaw, A. W.; Heinke, C. O.; Degenaar, N.; Wijnands, R.; Kaur, R.; Forestell, L. M.

    2017-10-01

    We present near-infrared (NIR) imaging observations of three transient neutron star X-ray binaries, SAX J1753.5-2349, SAX J1806.5-2215 and AX J1754.2-2754. All three sources are members of the class of 'very faint' X-ray transients which exhibit X-ray luminosities LX ≲ 1036 erg s-1. The nature of this class of sources is still poorly understood. We detect NIR counterparts for all three systems and perform multiband photometry for both SAX J1753.5-2349 and SAX J1806.5-2215, including narrow-band Br γ photometry for SAX J1806.5-2215. We find that SAX J1753.5-2349 is significantly redder than the field population, indicating that there may be absorption intrinsic to the system, or perhaps a jet is contributing to the infrared emission. SAX J1806.5-2215 appears to exhibit absorption in Br γ, providing evidence for hydrogen in the system. Our observations of AX J1754.2-2754 represent the first detection of an NIR counterpart for this system. We find that none of the measured magnitudes are consistent with the expected quiescent magnitudes of these systems. Assuming that the infrared radiation is dominated by either the disc or the companion star, the observed magnitudes argue against an ultracompact nature for all three systems.

  16. Characterization of maize allergens - MON810 vs. its non-transgenic counterpart.

    Science.gov (United States)

    Fonseca, Cátia; Planchon, Sébastien; Renaut, Jenny; Oliveira, Maria Margarida; Batista, Rita

    2012-04-03

    One of the main concerns about genetically modified foods and their potential impacts on human health is that the introduction of a new/ altered gene may putatively alter the expression of others, namely endogenous allergens. We intended to evaluate, and to compare, using quantitative real time RT-PCR technique, the expression of 5 already known maize allergens (Zea m14, Zea m25, Zea m27kD, 50kD Zein and trypsin inhibitor) in MON 810 vs. its non-transgenic counterpart, throughout seed development (10, 16 and 23days after pollination). We have shown that none of the tested allergen genes presented differential expression, with statistic significance, along all tested seed development stages, in MON810 vs. its conventional counterpart. We have also used bidimensional gel electrophoresis followed by Western blotting with plasma from two maize allergic subjects to characterize their immunologic responses against MON 810 vs. its non-transgenic control. Immunoreactive spots were characterized by MS. We have identified fourteen new IgE-binding proteins present in both transgenic and non-transgenic maize. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Off-axis short GRBs from structured jets as counterparts to GW events

    Science.gov (United States)

    Kathirgamaraju, Adithan; Barniol Duran, Rodolfo; Giannios, Dimitrios

    2018-01-01

    Binary neutron star mergers are considered to be the most favourable sources that produce electromagnetic (EM) signals associated with gravitational waves (GWs). These mergers are the likely progenitors of short duration gamma-ray bursts (GRBs). The brief gamma-ray emission (the 'prompt' GRB emission) is produced by ultrarelativistic jets, as a result, this emission is strongly beamed over a small solid angle along the jet. It is estimated to be a decade or more before a short GRB jet within the Laser Interferometer Gravitational-Wave observatory (LIGO) volume points along our line of sight. For this reason, the study of the prompt signal as an EM counterpart to GW events has been sparse. We argue that for a realistic jet model, one whose luminosity and Lorentz factor vary smoothly with angle, the prompt signal can be detected for a significantly broader range of viewing angles. This can lead to an 'off-axis' short GRB as an EM counterpart. Our estimates and simulations show that it is feasible to detect these signals with the aid of the temporal coincidence from a LIGO trigger, even if the observer is substantially misaligned with respect to the jet.

  18. Do Lower Calorie or Lower Fat Foods Have More Sodium Than Their Regular Counterparts?

    Directory of Open Access Journals (Sweden)

    Katherine A. John

    2016-08-01

    Full Text Available The objective of this study was to compare the sodium content of a regular food and its lower calorie/fat counterpart. Four food categories, among the top 20 contributing the most sodium to the US diet, met the criteria of having the most matches between regular foods and their lower calorie/fat counterparts. A protocol was used to search websites to create a list of “matches”, a regular and comparable lower calorie/fat food(s under each brand. Nutrient information was recorded and analyzed for matches. In total, 283 matches were identified across four food categories: savory snacks (N = 44, cheese (N = 105, salad dressings (N = 90, and soups (N = 44. As expected, foods modified from their regular versions had significantly reduced average fat (total fat and saturated fat and caloric profiles. Mean sodium content among modified salad dressings and cheeses was on average 8%–12% higher, while sodium content did not change with modification of savory snacks. Modified soups had significantly lower mean sodium content than their regular versions (28%–38%. Consumers trying to maintain a healthy diet should consider that sodium content may vary in foods modified to be lower in calories/fat.

  19. Search for Infrared Counterparts to X-Ray Point Sources in M 51 and NGC 4559

    Science.gov (United States)

    Clark, David M.; Eikenberry, Stephen S.; Brandl, Bernhard

    2006-02-01

    We propose to use the KPNO-4m telescope to take near-infrared (IR) images of the star-forming galaxies M51 and NGC 4559 to study the environments of their X-ray point sources. We chose these galaxies because of the extensive archival HST optical and Chandra X-ray observations of them. With our proposed observations, we will search for IR counterparts to X-ray binary sources. Many of these point sources are X-ray binaries containing a compact object that is left after the violent death of a massive star. By studying compact objects residing in the young stellar clusters where they formed, we can obtain the most interesting constraints on their environments and progenitor. Using these proposed observations along with HST and Chandra archival images, we will perform multi-wavelength studies on the stellar clusters associated with these X-ray sources. Fitting the photometry to Bruzual- Charlot spectral evolution models, we will estimate cluster mass, age and metallicity range. We will use this to constrain theories of compact object formation and evolution, particularly for the origins of the intermediate-mass black holes (IMBH) thought to power ultra-luminous X-ray sources (ULX). In future observations, we will acquire follow up spectra of the IR counterparts to study the cluster dynamics as well as rule out the possibility some ULXs are background quasars. We are requesting two nights on the KPNO-4m using FLAMINGOS to take J and K_s observations.

  20. Tribological Response of Heat Treated AISI 52100 Steels Against Steel and Ceramic Counterparts

    Directory of Open Access Journals (Sweden)

    Türedi E.

    2017-09-01

    Full Text Available AISI 52100 bearing steels are commonly used in applications requiring high hardness and abrasion resistance. The bearing steels are working under dynamic loads in service conditions and their toughness properties become important. In order to provide the desired mechanical properties, various heat treatments (austenizing, quenching and tempering are usually applied. In this study, AISI 52100 bearing steel samples were austenized at 900°C for ½ h and water quenched to room temperature. Then tempering was carried out at 795°C, 400°C and 200°C for ½ h. In order to investigate the effect of heat treatment conditions on wear behavior, dry friction tests were performed according to ASTM G99-05 Standard with a ‘ball-on-disk’ type tribometer. The samples were tested against steel and ceramic counterparts using the parameters of 100 m distance and 30 N load and 0.063 m/s rotational speed. After wear test, the surface characterization was carried out using microscopy. Wear loss values were calculated using a novel optical method on both flat and counterpart specimens.

  1. Optimizing Cooperative Cognitive Radio Networks with Opportunistic Access

    KAUST Repository

    Zafar, Ammar

    2012-09-16

    Optimal resource allocation for cooperative cognitive radio networks with opportunistic access to the licensed spectrum is studied. Resource allocation is based on minimizing the symbol error rate at the receiver. Both the cases of all-participate relaying and selective relaying are considered. The objective function is derived and the constraints are detailed for both scenarios. It is then shown that the objective functions and the constraints are nonlinear and nonconvex functions of the parameters of interest, that is, source and relay powers, symbol time, and sensing time. Therefore, it is difficult to obtain closed-form solutions for the optimal resource allocation. The optimization problem is then solved using numerical techniques. Numerical results show that the all-participate system provides better performance than its selection counterpart, at the cost of greater resources. © 2012 Ammar Zafar et al.

  2. The Application of Cognitive Radio to Coordinated Unmanned Aerial Vehicle (UAV) Missions

    Science.gov (United States)

    2011-06-01

    iii LIST OF FIGURES Figure 1 GNU Radio/ USRP -Based UAV Downlink Simulator...7 Figure 2 Block diagram representing transmitter and receiver setup and node interconnect configuration for USRP and USRP2 performance...25 Figure 15 UAV network running tests with 6 nodes. This image shows the USRP RF front ends used. ..... 25 LIST OF TABLES Table 1

  3. IA-Regional-Radio - Social Network for Radio Recommendation

    Science.gov (United States)

    Dziczkowski, Grzegorz; Bougueroua, Lamine; Wegrzyn-Wolska, Katarzyna

    This chapter describes the functions of a system proposed for the music hit recommendation from social network data base. This system carries out the automatic collection, evaluation and rating of music reviewers and the possibility for listeners to rate musical hits and recommendations deduced from auditor's profiles in the form of regional Internet radio. First, the system searches and retrieves probable music reviews from the Internet. Subsequently, the system carries out an evaluation and rating of those reviews. From this list of music hits, the system directly allows notation from our application. Finally, the system automatically creates the record list diffused each day depending on the region, the year season, the day hours and the age of listeners. Our system uses linguistics and statistic methods for classifying music opinions and data mining techniques for recommendation part needed for recorded list creation. The principal task is the creation of popular intelligent radio adaptive on auditor's age and region - IA-Regional-Radio.

  4. DA 495: An Aging Pulsar Wind Nebula with Possible TeV Gamma-Ray Counterpart

    Science.gov (United States)

    Coerver, Anna; Mori, Kaya; Hailey, Charles; Gotthelf, Eric; Mukherjee, Reshmi; Hui, Michelle; Dingus, Brenda; Goodman, Jordan; NuSTAR, HAWC, VERITAS

    2018-01-01

    A pulsar wind nebula is created when a high-mass star collapses and forms an isolated neutron star surrounded by a relativistic particle wind. DA 495 is thought to be such an object, although no pulsations have been detected. DA 495 was first detected in the radio band and is characterized by an annular radio morphology with a radio emission dip in the center. It has been theorized that the wind nebula has an unusually high magnetization of 1.3 mG, and the age of the PWN has been estimated from the 1.3 GHz energy break to be approximately 20 kyr. With such a high wind magnetization, one would expect synchrotron radiation to fall off fairly quickly, yet NuSTAR (the Nuclear Spectroscopic Telescope Array) detected hard X-rays at energies greater than 10 keV, and a study of the Galactic Plane by the HAWC very-high-energy (VHE) gamma-ray telescope revealed a source coincident with DA 495 at energies greater than 10 TeV. This source was also detected at TeV energies by the VERITAS gamma-ray telescope. DA 495 was detected in the X-ray up to 10 keV by both Chandra and XMM-Newton X-ray telescopes before NuSTAR performed follow-up observations of the region in June 2017. DA 495 is one of the first TeV sources observed by the NuSTAR-HAWC-VERITAS Galactic Legacy collaboration. We carried out spectral and imaging analysis of both NuSTAR and Chandra data on DA 495 and will present results of our study of DA 495.

  5. Industrial interference and radio astronomy

    Science.gov (United States)

    Jessner, A.

    2013-07-01

    The interferer - victim scenario is described for the case of industrial interference affecting radio astronomical observatories. The sensitivity of radio astronomical receivers and their interference limits are outlined. EMC above 30 MHz is a serious problem for Radio Astronomy. Interferer (CISPR) and victim (ITU-R RA 769) standards are not harmonised. The emissions from the interferer and their spectral characteristics are not defined sufficiently well by CISPR standards. The required minimum coupling losses (MCL) between an industrial device and radio astronomical antenna depends on device properties but is shown to exceed 140 dB in most cases. Spatial separation of a few km is insufficient on its own, the terrain must shield > 30-40 dB, additional mitigations such as extra shielding or suppression of high frequency emissions may be necessary. A case by case compatibility analysis and tailored EMC measures are required for individual installations. Aggregation of many weak rfi emitters can become serious problem. If deployment densities are high enough, the emission constraints can even exceed those for a single interferer at a short distance from the radio observatory. Compatibility studies must account not only for the single interferer but also for many widely distributed interference sources.

  6. Morphometric Analysis of the Mandible in Subjects with Class III Malocclusion

    OpenAIRE

    Jin-Yun Pan; Szu-Ting Chou; Hong-Po Chang; Pao-Hsin Liu

    2006-01-01

    This study evaluated the deformations that contribute to Class III mandibular configuration, employing geometric morphometric analysis. Lateral cephalograms of male and female groups of 100 young adults and 70 children with Class III malocclusion were compared to those of counterparts with normal occlusion. The sample included an equal number of both genders. The cephalographs were traced, and 12 homologous landmarks were identified and digitized. Average mandibular geometries were generated ...

  7. Radio-embolization for hepatocellular carcinoma; Traitement des carcinomes hepatocellulaires par injection intra-arterielle de radio-isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Raoul, J.L. [Departement d' oncologie medicale, centre Eugene-Marquis, rue de la bataille Flandres-Dunkerque, CS 44229, 35042 Rennes cedex (France); Inserm U911, centre Eugene-Marquis, CS 44229, 35042 Rennes cedex (France); Edeline, J.; Pracht, M.; Boucher, E. [Departement d' oncologie medicale, centre Eugene-Marquis, rue de la bataille Flandres-Dunkerque, CS 44229, 35042 Rennes cedex (France); Rolland, Y. [Departement d' imagerie medicale, centre Eugene-Marquis, CS 44229, 35042 Rennes cedex (France); Garin, E. [Inserm U911, centre Eugene-Marquis, CS 44229, 35042 Rennes cedex (France); Departement d' imagerie medicale, centre Eugene-Marquis, CS 44229, 35042 Rennes cedex (France)

    2011-02-15

    Hepatocellular carcinoma is now a major public health concern. In intermediate stages (one third of hepatocellular carcinoma patients), chemo-embolization is the standard of care despite a poor tolerance and a moderate efficacy. Moreover, despite recent improvements, this technique seems in a dead end. Radio-embolization could be an excellent tool for such patients. Currently {sup 131}I-Lipiodol, {sup 188}Re-Lipiodol, {sup 90}Y-glass or resin microspheres are available. More recent and promising data come from microspheres, but phase II and III studies are needed before drawing any conclusion. In the future, the combination of radio-embolization with systemic chemotherapy or targeted agents (particularly anti-angiogenic drugs) seems very promising. (authors)

  8. Off-axis emission of short γ-ray bursts and the detectability of electromagnetic counterparts of gravitational-wave-detected binary mergers

    Science.gov (United States)

    Lazzati, Davide; Deich, Alex; Morsony, Brian J.; Workman, Jared C.

    2017-10-01

    We present calculations of the wide angle emission of short-duration gamma-ray bursts from compact binary merger progenitors. Such events are expected to be localized by their gravitational wave emission, fairly irrespective of the orientation of the angular momentum vector of the system, along which the gamma-ray burst outflow is expected to propagate. We show that both the prompt and afterglow emission are dim and challenging to detect for observers lying outside the cone within which the relativistic outflow is propagating. If the jet initially propagates through a baryon contaminated region surrounding the merger site, however, a hot cocoon forms around it. The cocoon subsequently expands quasi-isotropically producing its own prompt emission and external shock powered afterglow. We show that the cocoon prompt emission is detectable by Swift BAT and Fermi GBM. We also show that the cocoon afterglow peaks a few hours to a few days after the burst and is detectable for up to a few weeks at all wavelengths. The timing and brightness of the transient are however uncertain due to their dependence on unknown quantities such as the density of the ambient medium surrounding the merger site, the cocoon energy and the cocoon Lorentz factor. For a significant fraction of the gravitationally detected neutron-star-binary mergers, the cocoon afterglow could possibly be the only identifiable electromagnetic counterpart, at least at radio and X-ray frequencies.

  9. Unseen cosmos the universe in radio

    CERN Document Server

    Graham-Smith, Francis

    2013-01-01

    Radio telescopes have transformed our understanding of the Universe. Pulsars, quasars, Big Bang cosmology: all are discoveries of the new science of radio astronomy. Here, Francis Graham-Smith describes the birth, development, and maturity of radio astronomy, from the first discovery of cosmic radio waves to its present role as a major part of modern astronomy. Radio is part of the electromagnetic spectrum, covering infra-red, visible light, ultraviolet, X-rays, and gamma-rays, and Graham-Smith explains why it is that radio waves give us a unique view of the Universe. Tracing the development o

  10. ¿Radio popular o comunitaria?

    Directory of Open Access Journals (Sweden)

    María Cristina Mata

    2015-01-01

    Full Text Available Conocidas como Radios populares o educativas en América Latina; Radio Rural o local en África; Radio pública en Australia y Radio libre o Asociativa en Europa todas en busca de la democratización de la comunicación a escala comunitaria y que se iniciaron hace casi medio siglo. En todas partes no deja de ser un tipo de radio hecha para servir al pueblo, una radio que favorece la expresión y la participación al tiempo que valora la cultura local.

  11. Reconfigurable radio systems network architectures and standards

    CERN Document Server

    Iacobucci, Maria Stella

    2013-01-01

    This timely book provides a standards-based view of the development, evolution, techniques and potential future scenarios for the deployment of reconfigurable radio systems.  After an introduction to radiomobile and radio systems deployed in the access network, the book describes cognitive radio concepts and capabilities, which are the basis for reconfigurable radio systems.  The self-organizing network features introduced in 3GPP standards are discussed and IEEE 802.22, the first standard based on cognitive radio, is described. Then the ETSI reconfigurable radio systems functional ar

  12. Magnetic filaments associated radio-source feedback

    Science.gov (United States)

    Birkinshaw, Mark; Worrall, Diana

    2015-08-01

    Heating of the intergalactic medium by radio sources must be associated with magnetization. We present a case study of a double radio galaxy system that shows extensive field injection through two different radio plume morphologies that both extend hundreds of kpc. One plume exhibits two exceptionally narrow radio-bright features which extend along much of its length. The extreme length-to-width radio of these filaments suggests that they trace organized and stable magnetic ropes that have been drawn out by the motion of the radio galaxy through the intergalactic mediu, and that dissipate only slowly.

  13. La Radio et ses publics

    OpenAIRE

    Glévarec, Hervé; Pinet, Michel

    2011-01-01

    Média ancien, fortement ancré dans les routines et les activités de la vie quotidienne, la radio est l’objet d’un fort investissement de la part des Français. Pourtant, l’intérêt scientifique à l’endroit des publics de la radio est relativement récent. On ne sait pas grand-chose de la structuration de cet univers qui offre en France une diversité remarquable de stations, privées musicales jeunes (NRJ, Fun radio, Skyrock…), adultes (Nostalgie, Virgin, RTL2…), généralistes (RTL, Europe 1), de s...

  14. Radio Context Awareness and Applications

    Directory of Open Access Journals (Sweden)

    Luca Reggiani

    2013-01-01

    Full Text Available The context refers to “any information that can be used to characterize the situation of an entity, where an entity can be a person, place, or physical object.” Radio context awareness is defined as the ability of detecting and estimating a system state or parameter, either globally or concerning one of its components, in a radio system for enhancing performance at the physical, network, or application layers. In this paper, we review the fundamentals of context awareness and the recent advances in the main radio techniques that increase the context awareness and smartness, posing challenges and renewed opportunities to added-value applications in the context of the next generation of wireless networks.

  15. Modular Software-Defined Radio

    Directory of Open Access Journals (Sweden)

    Rhiemeier Arnd-Ragnar

    2005-01-01

    Full Text Available In view of the technical and commercial boundary conditions for software-defined radio (SDR, it is suggestive to reconsider the concept anew from an unconventional point of view. The organizational principles of signal processing (rather than the signal processing algorithms themselves are the main focus of this work on modular software-defined radio. Modularity and flexibility are just two key characteristics of the SDR environment which extend smoothly into the modeling of hardware and software. In particular, the proposed model of signal processing software includes irregular, connected, directed, acyclic graphs with random node weights and random edges. Several approaches for mapping such software to a given hardware are discussed. Taking into account previous findings as well as new results from system simulations presented here, the paper finally concludes with the utility of pipelining as a general design guideline for modular software-defined radio.

  16. Phenomenology of magnetospheric radio emissions

    Science.gov (United States)

    Carr, T. D.; Desch, M. D.; Alexander, J. K.

    1983-01-01

    Jupiter has now been observed over 24 octaves of the radio spectrum, from about 0.01 MHz to 300,000 MHz. Its radio emissions fill the entire spectral region where interplanetary electromagnetic propagation is possible at wavelengths longer than infrared. Three distinct types of radiation are responsible for this radio spectrum. Thermal emission from the atmosphere accounts for virtually all the radiation at the high frequency end. Synchrotron emission from the trapped high-energy particle belt deep within the inner magnetosphere is the dominant spectral component from about 4000 to 40 MHz. The third class of radiation consists of several distinct components of sporadic low frequency emission below 40 MHz. The decimeter wavelength emission is considered, taking into account the discovery of synchrotron emission, radiation by high-energy electrons in a magnetic field, and the present status of Jovian synchrotron phenomenology. Attention is also given to the decameter and hectometer wavelength emission, and emissions at kilometric wavelengths.

  17. Radio Observations of the Pulsar Wind Nebula HESS J1303-631 with ATCA

    Science.gov (United States)

    Sushch, Iurii; Oya, Igor; Schwanke, Ullrich; Johnston, Simon; Dalton, Matthew

    2016-04-01

    Based on its enregy-dependent morphology the initially unidentified very high energy (VHE; E > 100 GeV) gamma-ray source HESS J1303-631 was recently associated with the pulsar PSR J1301-6305. Subsequent detection of X-ray and GeV counterparts further supports the identification of the H.E.S.S. source as evolved pulsar wind nebula (PWN). Recent radio observations of the PSR J1301-6305 region with ATCA dedicated to search for the radio counterpart of HESS J1303-631 are reported here. Observations at 5.5 GHz and 7.5 GHz do not reveal any extended emission associated with the pulsar. The analysis of the archival 1.384 GHz and 2.368 GHz data also does not show any significant emission. The 1.384 GHz data reveal a hint of an extended shell-like emission in the same region which might be a supernova remnant. The implications of the non-detection at radio wavelengths on the nature and evolution of the PWN as well as the possibility of the SNR candidate being a birth place of PSR J1301-6305 are discussed.

  18. CONSTRUCTIVISM AND REFLECTIVISM AS THE LOGICAL COUNTERPARTS IN TESOL: LEARNING THEORY VERSUS TEACHING METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Abdullah al Mahmud

    2013-07-01

    Full Text Available The gist of the entire constructivist learning theory is that learners are self-builders of their learning that occurs through a mental process in a social context or communication setting, and teachers as facilitators generate learning by creating the expected environment and/or utilizing the process. This article theoretically proves reflectivism as the logical counterpart of constructivism through establishing their complete interdependence andthen suggests certain strategies of reflection to be used in language teaching for ensuring the best possible constructivist learning of language learners. In doing so, the basic tenets of constructivism and reflective thoughts are elaborated, examining their mutual connection thoroughly in terms of constructivist recommendations. The research also focuses on three case studies to depict how the theory of constructivist learning principles comes into practice through judicious reviews or reflective process.

  19. Optimization of Integer Order Integrators for Deriving Improved Models of Their Fractional Counterparts

    Directory of Open Access Journals (Sweden)

    Maneesha Gupta

    2013-01-01

    Full Text Available Second and third order digital integrators (DIs have been optimized first using Particle Swarm Optimization (PSO with minimized error fitness function obtained by registering mean, median, and standard deviation values in different random iterations. Later indirect discretization using Continued Fraction Expansion (CFE has been used to ascertain a better fitting of proposed integer order optimized DIs into their corresponding fractional counterparts by utilizing their refined properties, now restored in them due to PSO algorithm. Simulation results for the comparisons of the frequency responses of proposed 2nd and 3rd order optimized DIs and proposed discretized mathematical models of half integrators based on them, with their respective existing operators, have been presented. Proposed integer order PSO optimized integrators as well as fractional order integrators (FOIs have been observed to outperform the existing recently published operators in their respective domains reasonably well in complete range of Nyquist frequency.

  20. Molecular characteristics of malignant ovarian germ cell tumors and comparison with testicular counterparts

    DEFF Research Database (Denmark)

    Kraggerud, Sigrid Marie; Hoei-Hansen, Christina E; Alagaratnam, Sharmini

    2013-01-01

    their similarity to pluripotent precursor cells (primordial germ cells, PGCs) and other stem cells. This similarity combined with the process of ovary development, explain why mOGCTs present so early in life, and with greater histological complexity, than most somatic solid tumors.......This review focuses on the molecular characteristics and development of rare malignant ovarian germ cell tumors (mOGCTs). We provide an overview of the genomic aberrations assessed by ploidy, cytogenetic banding, and comparative genomic hybridization. We summarize and discuss the transcriptome...... profiles of mRNA and microRNA (miRNA), and biomarkers (DNA methylation, gene mutation, individual protein expression) for each mOGCT histological subtype. Parallels between the origin of mOGCT and their male counterpart testicular GCT (TGCT) are discussed from the perspective of germ cell development...

  1. Spatial integration by a dielectric slab and its planar graphene-based counterpart.

    Science.gov (United States)

    Zangeneh-Nejad, Farzad; Khavasi, Amin

    2017-05-15

    In this contribution a new approach to perform spatial integration is presented using a dielectric slab. Our approach is indeed based on the fact that the transmission coefficient of a simple dielectric slab at its mode excitation angle matches the Fourier-Green's function of first-order integration. Inspired by the mentioned dielectric-based integrator, we further demonstrate its graphene-based counterpart. The latter is not only reconfigurable but also highly miniaturized in contrast to the previously reported designs [Opt. Commun.338, 457 (2015)OPCOB80030-401810.1016/j.optcom.2014.11.007]. Such integrators have the potential to be used in ultrafast analog computation and signal processing.

  2. Miniature EVA Software Defined Radio

    Science.gov (United States)

    Pozhidaev, Aleksey

    2012-01-01

    As NASA embarks upon developing the Next-Generation Extra Vehicular Activity (EVA) Radio for deep space exploration, the demands on EVA battery life will substantially increase. The number of modes and frequency bands required will continue to grow in order to enable efficient and complex multi-mode operations including communications, navigation, and tracking applications. Whether conducting astronaut excursions, communicating to soldiers, or first responders responding to emergency hazards, NASA has developed an innovative, affordable, miniaturized, power-efficient software defined radio that offers unprecedented power-efficient flexibility. This lightweight, programmable, S-band, multi-service, frequency- agile EVA software defined radio (SDR) supports data, telemetry, voice, and both standard and high-definition video. Features include a modular design, an easily scalable architecture, and the EVA SDR allows for both stationary and mobile battery powered handheld operations. Currently, the radio is equipped with an S-band RF section. However, its scalable architecture can accommodate multiple RF sections simultaneously to cover multiple frequency bands. The EVA SDR also supports multiple network protocols. It currently implements a Hybrid Mesh Network based on the 802.11s open standard protocol. The radio targets RF channel data rates up to 20 Mbps and can be equipped with a real-time operating system (RTOS) that can be switched off for power-aware applications. The EVA SDR's modular design permits implementation of the same hardware at all Network Nodes concept. This approach assures the portability of the same software into any radio in the system. It also brings several benefits to the entire system including reducing system maintenance, system complexity, and development cost.

  3. VizieR Online Data Catalog: A search for ultra-compact HVC counterparts (Sand+, 2015)

    Science.gov (United States)

    Sand, D. J.; Crnojevic, D.; Bennet, P.; Willman, B.; Hargis, J.; Strader, J.; Olszewski, E.; Tollerud, E. J.; Simon, J. D.; Caldwell, N.; Guhathakurta, P.; James, B. L.; Koposov, S.; McLeod, B.; Morrell, N.; Peacock, M.; Salinas, R.; Seth, A. C.; Stark, D. P.; Toloba, E.

    2015-10-01

    We have searched all available optical and ultraviolet imaging archives for counterparts to the ultra-compact high-velocity clouds (UCHVCs; see section 2.1 and table 1). In addition to our archival search for counterparts to the UCHVCs, we have also acquired some supplementary imaging of select systems with the Magellan/Megacam in 2013 Jun 11 and 2014 Apr 26-27 and the APO/SPICAM in 2014 Nov 17 (see section 2.2). We have obtained spectroscopic observations for all six of the strong dwarf galaxy candidates identified in our search. ALFALFA-Dw1 (HVC274.68+74.70-123) was observed with the Inamori- Magellan Areal Camera and Spectrograph (IMACS) on the Magellan Baade telescope on 2014 June 17 (UT). GALFA-Dw1 (GALFA source 003.7+10.8+236), also known as Pisces A was observed on 2014 June 29 (UT) using the Goodman High-Throughput Spectrograph on the SOAR 4.1m telescope. GALFA-Dw2 (GALFA source 019.8+11.1+617), also known as Pisces B, was observed on 2014 October 21 (UT) with the Blue Channel Spectrograph on the MMT. GALFA-Dw3 (GALFA source 044.7+13.6+528) and GALFA-Dw4 (GALFA source 086.4+10.8+611) were observed with the 3.5m Astrophysical Research Consortium Telescope at APO on 2014 November 18 (UT) using the Dual Imaging Spectrograph (DIS). The faint, blue optical source coincident with GALFA 162.1+12.5+434 (see Figure 2) was observed on 2014 December 24 (UT) with the Blue Channel Spectrograph on the MMT. (2 data files).

  4. Radio Relays Improve Wireless Products

    Science.gov (United States)

    2009-01-01

    Signal Hill, California-based XCOM Wireless Inc. developed radio frequency micromachine (RF MEMS) relays with a Phase II Small Business Innovation Research (SBIR) contract through NASA?s Jet Propulsion Laboratory. In order to improve satellite communication systems, XCOM produced wireless RF MEMS relays and tunable capacitors that use metal-to-metal contact and have the potential to outperform most semiconductor technologies while using less power. These relays are used in high-frequency test equipment and instrumentation, where increased speed can mean significant cost savings. Applications now also include mainstream wireless applications and greatly improved tactical radios.

  5. radio frequency emf radio frequency emf exposure due to gsm

    African Journals Online (AJOL)

    eobe

    point microwave radio, and satellite communications systems. The most recent concern is the safety .... examined by a set of equation called Maxwell's equations [5]. Mathematically, Maxwell derived a differential and integral wave form of the electric and magnetic equations in free space using four field quantities namely the ...

  6. Impact of African Farm Radio Research Initiative Participatory Radio ...

    African Journals Online (AJOL)

    zeleza

    The AFRRI participatory action research and radio communication/extension based project involved, per design, three Active Listening (ALC) communities of Labvu, Makombe and Lovimbi while Magodi and Chambakata acted as Passive Listening Communities (PLC) and. Control Communities (CC). ALC participants were ...

  7. Radio Astronomy and the Giant Metre-Wave Radio Telescope

    Indian Academy of Sciences (India)

    but the energy of each type of wave varies inversely with its wavelength. Thus ... parent to radio-waves; much of the galaxy is also transparent to ..... stars in the galaxies. The im- age has been inverted (like a film negative) so darker re- gions in the image are ac- tually brighter. In the opti- cal image the two galaxies.

  8. Intelligent Cognitive Radio Models for Enhancing Future Radio Astronomy Observations

    Directory of Open Access Journals (Sweden)

    Ayodele Abiola Periola

    2016-01-01

    Full Text Available Radio astronomy organisations desire to optimise the terrestrial radio astronomy observations by mitigating against interference and enhancing angular resolution. Ground telescopes (GTs experience interference from intersatellite links (ISLs. Astronomy source radio signals received by GTs are analysed at the high performance computing (HPC infrastructure. Furthermore, observation limitation conditions prevent GTs from conducting radio astronomy observations all the time, thereby causing low HPC utilisation. This paper proposes mechanisms that protect GTs from ISL interference without permanent prevention of ISL data transmission and enhance angular resolution. The ISL transmits data by taking advantage of similarities in the sequence of observed astronomy sources to increase ISL connection duration. In addition, the paper proposes a mechanism that enhances angular resolution by using reconfigurable earth stations. Furthermore, the paper presents the opportunistic computing scheme (OCS to enhance HPC utilisation. OCS enables the underutilised HPC to be used to train learning algorithms of a cognitive base station. The performances of the three mechanisms are evaluated. Simulations show that the proposed mechanisms protect GTs from ISL interference, enhance angular resolution, and improve HPC utilisation.

  9. radio frequency based radio frequency based water level monitor

    African Journals Online (AJOL)

    eobe

    Key words: radio frequency, PIC microcontroller, encoder, decoder, water pump, residential. 1. ... The sensors emit high frequency (20kHz to 200 kHz) acoustic waves that are reflected back to and detected by the emitting transducer [2-4]. In addition, optical interface ... is another method; in this method optical sensors are.

  10. Visible and near-infrared intense luminescence from water-soluble lanthanide [Tb(III), Eu(III), Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), Er(III)] complexes.

    Science.gov (United States)

    Quici, Silvio; Cavazzini, Marco; Marzanni, Giovanni; Accorsi, Gianluca; Armaroli, Nicola; Ventura, Barbara; Barigelletti, Francesco

    2005-02-07

    The synthesis of a new ligand (1) containing a single phenanthroline (phen) chromophore and a flexibly connected diethylenetriamine tetracarboxylic acid unit (DTTA) as a lanthanide (Ln) coordination site is reported [1 is 4-[(9-methyl-1,10-phenantrol-2-yl)methyl]-1,4,7-triazaheptane-1,1,7,7-tetraacetic acid]. From 1, an extended series of water-soluble Ln.1 complexes was obtained, where Ln is Eu(III), Tb(III), Gd(III), Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III). The stoichiometry for the association was found 1:1, with an association constant K(A) > or = 10(7) s(-1) as determined by employing luminescence spectroscopy. The luminescence and photophysical properties of the series of lanthanide complexes were investigated in both H2O and D2O solutions. High efficiencies for the sensitized emission, phi(se), in air-equilibrated water were observed for the Ln.1 complexes of Eu(III) and Tb(III) in the visible region (phi(se) = 0.24 and 0.15, respectively) and of Sm(III), Dy(III), Pr(III), Ho(III), Yb(III), Nd(III), and Er(III) in the vis and/or near-infrared region [phi(se) = 2.5 x 10(-3), 5 x 10(-4), 3 x 10(-5), 2 x 10(-5), 2 x 10(-4), 4 x 10(-5), and (in D2O) 4 x 10(-5), respectively]. For Eu.1 and Tb.1, luminescence data for water and deuterated water allowed us to estimate that no solvent molecules (q) are bound to the ion centers (q = 0). Luminescence quenching by oxygen was investigated in selected cases.

  11. AND Dy(III)

    African Journals Online (AJOL)

    userpc

    SYNTHESIS, SPECTROSCOPIC CHARACTERIZATION AND BIOLOGICAL. ACTIVITIES OF Sm(III) AND Dy(III) COMPLEXES WITH SCHIFF BASE DERIVED FROM. 2-HYDROXY-1-NAPHTHALDEHYDE AND 2-AMINOBENZOIC ACID. 1Bashir, S.S. and Abdulhadi, A. 1Department of Chemistry, Rabi'u Musa Kwankwaso ...

  12. Perkembangan dan Problematika Radio Komunitas di Indonesia

    Directory of Open Access Journals (Sweden)

    Masduki .

    2013-12-01

    Full Text Available Abstract: This article is about the development of community radio in Indonesia, it is problems and solutions. Community radio in Indonesia developed as an alternative to both public radio and commercial radio after the fall of Soeharto in 1998. Two important features of community radio are that it provides all community members with equal access to information, enhancing their rights and obligations, access to justice, public accountability and also enables them to participate actively in radio management and production. Both features enhance people’s selfawareness and sense of belonging to a community. The expansion of the progressive, participatory, community ownership, and non-profit model of community radio, has become a third sector of communication beside the commercial or state media. The dynamic development of community radio in Indonesia faced several problems starting from it is definition, implementation of regulation until standards of programmes operation based on the concept of community approach and participation

  13. Radio Search for Alien Space Probes

    Science.gov (United States)

    Arkhipov, A. V.

    It is shown that the search for alien space probes by occasional interceptions of their radio communication beams appears to be a promising task not beyond the ability of amateur radio astronomers and all-sky monitoring systems.

  14. RADIO-QUIET AND RADIO-LOUD PULSARS: SIMILAR IN GAMMA-RAYS BUT DIFFERENT IN X-RAYS

    Energy Technology Data Exchange (ETDEWEB)

    Marelli, M.; Mignani, R. P.; Luca, A. De; Salvetti, D. [INAF—Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via E. Bassini 15, I-20133, Milano (Italy); Parkinson, P. M. Saz [Santa Cruz Institute for Particle Physics, Department of Physics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Hartog, P. R. Den [Stanford University HEPL/KIPAC, 452 Lomita Mall, Stanford, CA 94305-4085 (United States); Wolff, M. T., E-mail: marelli@iasf-milano.inaf.it [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States)

    2015-04-01

    We present new Chandra and XMM-Newton observations of a sample of eight radio-quiet (RQ) γ-ray pulsars detected by the Fermi Large Area Telescope. For all eight pulsars we identify the X-ray counterpart, based on the X-ray source localization and the best position obtained from γ-ray pulsar timing. For PSR J2030+4415 we found evidence for a ∼10″-long pulsar wind nebula. Our new results consolidate the work from Marelli et al. and confirm that, on average, the γ-ray-to-X-ray flux ratios (F{sub γ}/F{sub X}) of RQ pulsars are higher than for the radio-loud (RL) ones. Furthermore, while the F{sub γ}/F{sub X} distribution features a single peak for the RQ pulsars, the distribution is more dispersed for the RL ones, possibly showing two peaks. We discuss possible implications of these different distributions based on current models for pulsar X-ray emission.

  15. Distributed optimization of a multisubchannel Ad Hoc cognitive radio network

    KAUST Repository

    Leith, Alex

    2012-05-01

    In this paper, we study the distributed-duality-based optimization of a multisubchannel ad hoc cognitive radio network (CRN) that coexists with a multicell primary radio network (PRN). For radio resource allocation in multiuser orthogonal frequency-division multiplexing (MU-OFDM) systems, the orthogonal-access-based exclusive subchannel assignment (ESA) technique has been a popular method, but it is suboptimal in ad hoc networks, because nonorthogonal access between multiple secondary-user links by using shared subchannel assignment (SSA) can bring a higher weighted sum rate. We utilize the Lagrangian dual composition tool and design low-complexity near-optimal SSA resource allocation methods, assuming practical discrete-rate modulation and that the CRN-to-PRN interference constraint has to strictly be satisfied. However, available SSA methods for CRNs are either suboptimal or involve high complexity and suffer from slow convergence. To address this problem, we design fast-convergence SSA duality schemes and introduce several novel methods to increase the speed of convergence and to satisfy various system constraints with low complexity. For practical implementation in ad hoc CRNs, we design distributed-duality schemes that involve only a small number of CRN local information exchanges for dual update. The effects of many system parameters are presented through simulation results, which show that the near-optimal SSA duality scheme can perform significantly better than the suboptimal ESA duality and SSA-iterative waterfilling schemes and that the performance loss of the distributed schemes is small, compared with their centralized counterparts. © 2012 IEEE.

  16. Zero-Power Radio Device.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert W.

    2018-02-01

    This report describes an unpowered radio receiver capable of detecting and responding to weak signals t ransmit ted from comparatively lon g distances . This radio receiver offers key advantages over a short range zero - power radio receiver pre viously described in SAND2004 - 4610, A Zero - Power Radio Receiver . The device described here can be fabricated as an integrated circuit for use in portable wireless devices, as a wake - up circuit, or a s a stand - alone receiver operating in conjunction with identification decoders or other electroni cs. It builds on key sub - components developed at Sandia National L aboratories o ver many years. It uses surface acous tic wave (SAW) filter technology. It uses custom component design to e nable the efficient use of sma ll aperture antennas. This device uses a key component, the pyroelectric demodulator , covered by Sandia owned U.S. Patent 7397301, Pyroelectric Demodulating Detector [1] . This device is also described in Sandia owned U.S. Patent 97266446, Zero Power Receiver [2].

  17. Radio frequency modulation made easy

    CERN Document Server

    Faruque, Saleh

    2017-01-01

    This book introduces Radio Frequency Modulation to a broad audience. The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications. The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  18. RADIO NOISE ADVANCES SEXUAL MATURITY

    African Journals Online (AJOL)

    ansistf-lewis

    Supplementary radio noise advances sexual maturity in domestic pullets exposed to 7-h photoperiods. P.D. Lewis. #. , B.A. Middleton. 1 and R.M. Gous. Animal and Poultry Science, School of Agricultural Sciences and Agribusiness, University of KwaZulu-Natal,. Scottsville 3209, South Africa. 1 School of Biomedical and ...

  19. A repeating fast radio burst

    Science.gov (United States)

    Spitler, L. G.; Scholz, P.; Hessels, J. W. T.; Bogdanov, S.; Brazier, A.; Camilo, F.; Chatterjee, S.; Cordes, J. M.; Crawford, F.; Deneva, J.; Ferdman, R. D.; Freire, P. C. C.; Kaspi, V. M.; Lazarus, P.; Lynch, R.; Madsen, E. C.; McLaughlin, M. A.; Patel, C.; Ransom, S. M.; Seymour, A.; Stairs, I. H.; Stappers, B. W.; van Leeuwen, J.; Zhu, W. W.

    2016-03-01

    Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.

  20. Link Dependent Adaptive Radio Simulation

    Science.gov (United States)

    2014-06-01

    of Electrical and Computer Engineering Morgan State University ABSTRACT This paper shows the optimized Link Dependent Adaptive Radio (LDAR...Instrumentation (PEO STRI ). 9 9. REFERENCES [1] M. Elrais, B. Mengiste, B. Gautam and E. Dambia, "Variable OFDM Performance on Aeronautical

  1. Kashima 34-m Radio Telescope

    Science.gov (United States)

    Sekido, Mamoru; Kawai, Eiji

    2013-01-01

    The Kashima 34-m radio telescope has been continuously operated and maintained by the National Institute of Information and Communications Technology (NICT) as a facility of the Kashima Space Technology Center (KSTC) in Japan. This brief report summarizes the status of this telescope, the staff, and activities during 2012.

  2. Radio Relics in Cosmological Simulations

    Indian Academy of Sciences (India)

    Radio relics have been discovered in many galaxy clusters. They are believed to trace shock fronts induced by cluster mergers. Cosmological simulations allow us to study merger shocks in detail since the intra-cluster medium is heated by shock dissipation. Using high resolution cosmological simulations, identifying shock ...

  3. Radio frequency propagation made easy

    CERN Document Server

    Faruque, Saleh

    2015-01-01

    This book introduces Radio Frequency Propagation to a broad audience.  The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications.  The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  4. Utrecht and Galactic Radio Astronomy

    NARCIS (Netherlands)

    van Woerden, H.

    Important roles in early Dutch Galactic radio astronomy were played by several Utrecht astronomers: Van de Hulst, Minnaert and Houtgast. The poster announcing the conference contained a number of pictures referring to scientific achievements of the Astronomical Institute Utrecht. One of these

  5. GNU Based Security in Software Defined Radio

    OpenAIRE

    H. B. Bhadka

    2012-01-01

    Various new technologies are explored for radio communication toward the 21st century. Among them the technology of "software defined radio" attracts large attention. Software Defined Radio (SDR) technology implements some of the functional modules of a radio system in software enabling highly flexible handsets. SDR devices may be reconfigured dynamically via the download of new software modules. Malicious or malfunctioning downloaded software present serious security risks to SDR devices and...

  6. Newnes radio and electronics engineer's pocket book

    CERN Document Server

    Moorshead, H W; Perry, J

    1978-01-01

    Newnes Radio and Electronics Engineer's Pocket Book, Fifteenth Edition provides reference of the information relevant in radio and electronics engineering. The book presents tables, illustrations, and diagrams of various data used in radio and electronics engineering. The coverage of the text includes abbreviations and symbols, electrical equations, and code conversions. The text will be useful to engineers, technicians, and other professionals who require a reference about the different aspects of radio and electronics.

  7. Spectrum Sharing Models in Cognitive Radio

    OpenAIRE

    Rifà Pous, Helena; Rifà Coma, Josep

    2011-01-01

    Spectrum scarcity demands thinking new ways to manage the distribution of radio frequency bands so that its use is more effective. The emerging technology that can enable this paradigm shift is the cognitive radio. Different models for organizing and managing cognitive radios have emerged, all with specific strategic purposes. In this article we review the allocation spectrum patterns of cognitive radio networks and analyse which are the common basis of each model.We expose the vulne...

  8. Unusual Solar Decameter Radio Bursts with High Frequency Cut off

    Science.gov (United States)

    Brazhenko, A. I.; Melnik, V. M.; Frantsuzenko, A. V.; Rucker, H. O.; Panchenko, M.

    2015-03-01

    Solar bursts with high frequency cut off were observed by the URAN-2 radio telescope (Poltava, Ukraine) on 18 August, 2012 in the frequency range 8-32 MHz. Durations of these bursts changed from 30 to 70 s. It is much longer than that for standard type III bursts. Drift rates are much smaller than those of type III bursts are, though much larger than those for decameter type II bursts. In some cases, the drift rate sign changes from the negative to positive one. Some of these bursts have fine structures. Stripes of the fine structures have small drift rates of 20-40 kHz/s. Polarizations of these bursts made about 10 % that apparently indicates that they are generated at the second harmonic of the local plasma frequency. The connection of bursts with the high frequency cut off with compact ejections from the behind-limb active regions is confirmed.

  9. Cognitive radios for dynamic spectrum access - Polyphase Multipath Radio Circuits for Dynamic Spectrum Access

    NARCIS (Netherlands)

    Klumperink, Eric A.M.; Shrestha, R.; Mensink, E.; Arkesteijn, V.J.; Nauta, Bram

    2007-01-01

    ABSTRACT Dynamic access of unused spectrum via a cognitive radio asks for flexible radio circuits that can work at an arbitrary radio frequency. This article reviews techniques to realize radios without resorting to frequency selective dedicated filters. In particular, a recently proposed polyphase

  10. 47 CFR 90.185 - Multiple licensing of radio transmitting equipment in the mobile radio service.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Multiple licensing of radio transmitting equipment in the mobile radio service. 90.185 Section 90.185 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Policies...

  11. Under the Radar: The First Woman in Radio Astronomy, Ruby Payne-Scott

    Science.gov (United States)

    Miller Goss, W.

    2012-05-01

    Under the Radar, the First Woman in Radio Astronomy, Ruby Payne-Scott W. Miller Goss, NRAO Socorro NM Ruby Payne-Scott (1912-1981) was an eminent Australian scientist who made major contributions to the WWII radar effort (CSIR) from 1941 to 1945. In late 1945, she pioneered radio astronomy efforts at Dover Heights in Sydney, Australia at a beautiful cliff top overlooking the Tasman Sea. Again at Dover Heights, Payne-Scott carried out the first interferometry in radio astronomy using an Australian Army radar antenna as a radio telescope at sun-rise, 26 January 1946. She continued these ground breaking activities until 1951. Ruby Payne-Scott played a major role in discovering and elucidating the properties of Type III bursts from the sun, the most common of the five classes of transient phenomena from the solar corona. These bursts are one of the most intensively studied forms of radio emission in all of astronomy. She is also one of the inventors of aperture synthesis in radio astronomy. I examine her career at the University of Sydney and her conflicts with the CSIR hierarchy concerning the rights of women in the work place, specifically equal wages and the lack of permanent status for married women. I also explore her membership in the Communist Party of Australia as well as her partially released Australian Scientific Intelligence Organization file. Payne-Scott’s role as a major participant in the flourishing radio astronomy research of the post war era remains a remarkable story. She had a number of strong collaborations with the pioneers of early radio astronomy in Australia: Pawsey, Mills, Christiansen, Bolton and Little. I am currently working on a popular version of the Payne-Scott story; “Making Waves, The Story of Ruby Payne-Scott: Australian Pioneer Radio Astronomer” will be published in 2013 by Springer in the Astronomers’ Universe Series.

  12. Discovery of the optical counterparts to four energetic Fermi millisecond pulsars

    Energy Technology Data Exchange (ETDEWEB)

    Breton, R. P. [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Van Kerkwijk, M. H. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Roberts, M. S. E. [Eureka Scientific Inc., 2452 Delmer Street, Suite 100, Oakland, CA 94602-3017 (United States); Hessels, J. W. T. [ASTRON, The Netherlands Institute for Radio Astronomy, Postbus 2, 7990-AA Dwingeloo (Netherlands); Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, 550 West, 120th Street, New York, NY 10027 (United States); McLaughlin, M. A. [Department of Physics, White Hall, West Virginia University, Morgantown, WV 26506 (United States); Ransom, S. M. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Ray, P. S. [Space Science Division, Naval Research Laboratory, Code 7655, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Stairs, I. H., E-mail: r.breton@soton.ac.uk [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada)

    2013-06-01

    In the last few years, over 43 millisecond radio pulsars have been discovered by targeted searches of unidentified γ-ray sources found by the Fermi Gamma-Ray Space Telescope. A large fraction of these millisecond pulsars are in compact binaries with low-mass companions. These systems often show eclipses of the pulsar signal and are commonly known as black widows and redbacks because the pulsar is gradually destroying its companion. In this paper, we report on the optical discovery of four strongly irradiated millisecond pulsar companions. All four sources show modulations of their color and luminosity at the known orbital periods from radio timing. Light curve modeling of our exploratory data shows that the equilibrium temperature reached on the companion's dayside with respect to their nightside is consistent with about 10%-30% of the available spin-down energy from the pulsar being reprocessed to increase the companion's dayside temperature. This value compares well with the range observed in other irradiated pulsar binaries and offers insights about the energetics of the pulsar wind and the production of γ-ray emission. In addition, this provides a simple way of estimating the brightness of irradiated pulsar companions given the pulsar spin-down luminosity. Our analysis also suggests that two of the four new irradiated pulsar companions are only partially filling their Roche lobe. Some of these sources are relatively bright and represent good targets for spectroscopic follow-up. These measurements could enable, among other things, mass determination of the neutron stars in these systems.

  13. Radiografia de la radio en Espana

    National Research Council Canada - National Science Library

    Rodero Anton, Emma; Sanchez Serrano, Chelo

    2007-01-01

    ... a la crisis que atraviesa el medio en un intento de dibujar una radiografia de la radio en Espana. La radio tiene futuro, pero hay que trabajar activamente por el. Que la radio siga siendo parte del sonido de nuestra vida dependera, en definitiva, del trabajo de todos nosotros: empresas, anunciantes, profesionales, universitarios, investigadores y oyentes.

  14. Making Waves: Pirate Radio and Popular Music.

    Science.gov (United States)

    Jones, Steve

    The history of pirate radio--radio broadcasts offered by unlicensed broadcasters as alternatives to licensed, commercial radio programming--is difficult to trace, both in America and the United Kingdom (UK) since mention of pirate broadcasts of a less-then-thrilling nature are rarely found. Also, until 1927, the U.S. government did not formally…

  15. Radio, Convergence and Development in Africa | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Radio remains the dominant mass medium in Africa, and indeed across much of the developing world. Moreover, radio is increasing its reach and interactivity as a result of changes in the regulatory environment, the growth of citizen journalism and convergence between radio and other information and communication ...

  16. 46 CFR 169.715 - Radio.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Radio. 169.715 Section 169.715 Shipping COAST GUARD..., Miscellaneous Systems, and Equipment § 169.715 Radio. (a) Radiotelegraph and radiotelephone installations are... Regulations, part 83. (b) A valid certificate issued by the FCC is evidence that the radio installation is in...

  17. 47 CFR 80.1075 - Radio records.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Radio records. 80.1075 Section 80.1075 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE... incidents connected with the radio-communication service which appear to be of importance to safety of life...

  18. Politics and Radio in the 1924 Campaign.

    Science.gov (United States)

    Berkman, Dave

    1987-01-01

    Discusses the relation between radio broadcasting and politics in the 1924 presidential campaign, focusing on newspaper and magazine coverage. Notes radio's influence on candidate image, the aspect of censorship, and the use of radio during the campaign and after the election. (MM)

  19. The health concerns and behaviours of primigravida: comparing advanced age pregnant women with their younger counterparts.

    Science.gov (United States)

    Loke, Alice Yuen; Poon, Chung Fan

    2011-04-01

    This study was to describe and compare the health concerns, behaviours and anxiety of advanced age pregnant women (35 years and older) with their younger counterparts. Women have specific health concerns and behaviours during pregnancy. Delayed childbearing has an increased risk of adverse pregnancy outcomes and advanced age pregnant women may have more health concerns than younger ones. A cross-sectional study. Primigravidae Chinese women aged 35 or older (n = 47) and 188 younger than aged 35 were recruited in February and March of 2005 by convenient sampling from the antenatal clinic of a regional hospital in Hong Kong to complete a questionnaire. Advanced age pregnant women when compared with their counterparts were more likely to have tertiary education (42·6% vs. 28·7%) and a higher family monthly income of Hong Kong $40,001 or more (40·5% vs. 15·4%). They were more likely to be concerned the possibility of miscarriage (63·8% vs. 45·9%) and the physical demands of caring for the newborn (61·7% vs. 45·4%) but were more likely to take up healthy behaviours such as 'eating nutritious food' (100%) and avoiding 'wearing tight clothing and high-heel shoes'(100%). Advanced age women were more likely to be concerned about their 'recovery after childbirth' (63·8% vs. 42·7%), Down's syndrome (70·2% vs. 37·8%) and structural defects of their foetus (78·7% vs. 54·1%). The results of this study provide a background for improving prenatal care catering for the specific health concerns of the advanced aged and promotion of health behaviours among younger pregnant women. Antenatal, obstetric and community health nurses have the responsibility to provide education and support services catering to the special concerns of pregnant women at different ages. Health professionals should promote the prime time for childbearing and deliver messages regarding the potential problems associated with later childbearing at premarital counselling. © 2011 Blackwell Publishing

  20. De radio en radio: el escenario radiofónico

    Directory of Open Access Journals (Sweden)

    Lic. Dulce María García Dávila

    1999-01-01

    Full Text Available Este artículo discierne sobre concepciones modernas de programación radiofónica y presenta los resultados que arrojó el estudio del escenario radiofónico de la ciudad de Maracaibo, con el uso de la técnica de la audiografía. Nos ofrece una descripción de los tipos de programación, la música, los programas informativos y de opinión, las estrategias de promoción y publicitarias más utilizadas por las emisoras de amplitud modulada en la ciudad. Este estudio forma parte de una primera etapa del proyecto de investigación titulado "Hacia un modelo de radio educativa y popular para el Occidente del país, a partir de la experiencia de Radio Fe y Alegría 850 AM".

  1. Probing extra dimension through gravitational wave observations of compact binaries and their electromagnetic counterparts

    CERN Document Server

    Yu, Hao; Huang, Fa Peng; Wang, Yong-Qiang; Meng, Xin-He; Liu, Yu-Xiao

    2016-01-01

    The gravitational wave (GW) observations of compact binaries and their possible electromagnetic counterparts may be used to probe the nature of the extra dimension. It is widely accepted that gravitons and photons are the only two completely confirmed objects that can travel along the null geodesics in our four-dimensional space-time. But when one considers that there exists the fifth dimension and only the GW can propagate freely in the bulk, the causal propagations of the GW and electromagnetic wave (EMW) are in general different. In this paper, we compute the null geodesics of the GW and EMW in a five-dimensional anti-de Sitter space-time and our four-dimensional universe in the present of the curvature of universe $k$, respectively. We show that for general cases the horizon radius of the GW is longer than the EMW within the equal time. Taking the GW 150914 event detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and the X-ray event detected by the Fermi Gamma-ray Burst Mo...

  2. Captive coyotes compared to their counterparts in the wild: does environmental enrichment help?

    Science.gov (United States)

    Shivik, John A; Palmer, Gemma L; Gese, Eric M; Osthaus, Britta

    2009-01-01

    This article attempts to determine the effects of environment (captive or wild) and a simple form of environmental enrichment on the behavior and physiology of a nonhuman animal. Specifically, analyses first compared behavioral budgets and stereotypic behavior of captive coyotes (Canis latrans) in kennels and pens to their counterparts in the wild. Second, experiments examined the effect of a simple form of environmental enrichment for captive coyotes (food-filled bones) on behavioral budgets, stereotypies, and corticosteroid levels. Overall, behavioral budgets of captive coyotes in both kennels and pens were similar to those observed in the wild, but coyotes in captivity exhibited significantly more stereotypic behavior. Intermittently providing a bone generally lowered resting and increased foraging behaviors but did not significantly reduce stereotypic behavior or alter corticosteroid levels. Thus, coyote behavior in captivity can be similar to that exhibited in the wild; in addition, although enrichment can affect proportions of elicited behaviors, abnormal behaviors and corticosteroid levels may require more than a simple form of environmental enrichment for their reduction.

  3. Access and Social Capital: A Profile of Community College and Global Counterparts

    Directory of Open Access Journals (Sweden)

    Rosalind Latiner Raby

    2014-12-01

    Full Text Available Alternatives to the traditional four-year public and private university include a sector of higher education that offers a more advanced curriculum than secondary school and serves as a local and often lower-cost pathway that gives options for university overflow for adult learners, displaced workers, life-long learners, workforce learners, developmental learners, and non-traditional learners (Raby and Valeau 2009. These institutional types are known by several names including College of Further Education, Community College, Polytechnic, Technical College, and Technical and Further Education (TAFE and are found on all continents. Based on a literature review of 1,083 academic publications these institutions share a mission that views educational access as necessary for growing the economic and social capital that is needed to help students improve lives. Central to this mission is the belief that any amount of post-secondary education is life-enhancing, regardless of length of study or level of completion. This article examines application of this mission at community colleges and global counterparts throughout the world.

  4. Probing the infrared counterparts of diffuse far-ultraviolet sources in the Galaxy

    Science.gov (United States)

    Saikia, Gautam; Shalima, P.; Gogoi, Rupjyoti; Pathak, Amit

    2017-12-01

    Recent availability of high quality infrared (IR) data for diffuse regions in the Galaxy and external galaxies have added to our understanding of interstellar dust. A comparison of ultraviolet (UV) and IR observations may be used to estimate absorption, scattering and thermal emission from interstellar dust. In this paper, we report IR and UV observations for selective diffuse sources in the Galaxy. Using archival mid-infrared (MIR) and far-infrared (FIR) observations from Spitzer Space Telescope, we look for counterparts of diffuse far-ultraviolet (FUV) sources observed by the Voyager, Far Ultraviolet Spectroscopic Explorer (FUSE) and Galaxy Evolution Explorer (GALEX) telescopes in the Galaxy. IR emission features at 8 μm are generally attributed to Polycyclic Aromatic Hydrocarbon (PAH) molecules, while emission at 24 μm are attributed to Very Small Grains (VSGs). The data presented here is unique and our study tries to establish a relation between various dust populations. By studying the FUV-IR correlations separately at low and high latitude locations, we have identified the grain component responsible for the diffuse FUV emission.

  5. Are red-tailed hawks and great horned owls diurnal-nocturnal dietary counterparts?

    Science.gov (United States)

    Marti, C.D.; Kochert, Michael N.

    1995-01-01

    Red-tailed Hawks (Buteo jamaicensis) and Great Homed Owls (Bubo virginianus)are common in North America where they occupy a wide range of habitats, often sympatrically. The two species are similar in size and have been portrayed as ecological counterparts, eating the same prey by day and night. We tested the trophic similarity of the two species by comparing published dietary data from across the United States. Both species ate primarily mammals and birds, and mean proportions of those two prey types did not differ significantly between diets of the two raptors. Red-tailed Hawks ate significantly more reptiles, and Great Homed Owls significantly more invertebrates. Dietary diversity was not significantly different at the level of prey taxonomic class, and diet overlap between the two species averaged 91%. At the prey species level, dietary overlap averaged only 50%, and at that level Red-tailed Hawk dietary diversity was significantly greater than that of Great Horned Owls. Mean prey mass of Red-tailed Hawks was significantly greater than that of Great Homed Owls. Populations of the two species in the western United States differed trophically more than did eastern populations. We conclude that, although the two species are generalist predators, they take largely different prey species in the same localities resulting in distinctive trophic characteristics.

  6. BurstCube: A CubeSat for Gravitational Wave Counterparts

    Science.gov (United States)

    Perkins, Jeremy S.; Racusin, Judith; Briggs, Michael; de Nolfo, Georgia; Caputo, Regina; Krizmanic, John; McEnery, Julie E.; Shawhan, Peter; Morris, David; Connaughton, Valerie; Kocevski, Dan; Wilson-Hodge, Colleen A.; Hui, Michelle; Mitchell, Lee; McBreen, Sheila

    2018-01-01

    We present BurstCube, a novel CubeSat that will detect and localize Gamma-ray Bursts (GRBs). BurstCube is a selected mission that will detect long GRBs, attributed to the collapse of massive stars, short GRBs (sGRBs), resulting from binary neutron star mergers, as well as other gamma-ray transients in the energy range 10-1000 keV. sGRBs are of particular interest because they are predicted to be the counterparts of gravitational wave (GW) sources soon to be detectable by LIGO/Virgo. BurstCube contains 4 CsI scintillators coupled with arrays of compact low-power Silicon photomultipliers (SiPMs) on a 6U Dellingr bus, a flagship modular platform that is easily modifiable for a variety of 6U CubeSat architectures. BurstCube will complement existing facilities such as Swift and Fermi in the short term, and provide a means for GRB detection, localization, and characterization in the interim time before the next generation future gamma-ray mission flies, as well as space-qualify SiPMs and test technologies for future use on larger gamma-ray missions. The ultimate configuration of BurstCube is to have a set of ~10 BurstCubes to provide all-sky coverage to GRBs for substantially lower cost than a full-scale mission.

  7. Postprandial hypoglycemic effect of mulberry leaf in Goto-Kakizaki rats and counterpart control Wistar rats.

    Science.gov (United States)

    Park, Ji Min; Bong, Ha Yoon; Jeong, Hye In; Kim, Yeon Kyoung; Kim, Ji Yeon; Kwon, Oran

    2009-01-01

    Postprandial hypoglycemic effect of mulberry leaf (Morus alba L.) was compared in two animal models: Goto-Kakizaki (GK) rats, a spontaneous non-obese animal model for type II diabetes, and their counterpart control Wistar rats. First, the effect of a single oral administration of mulberry leaf aqueous extract (MLE) on postprandial glucose responses was determined using maltose or glucose as substrate. With maltose-loading, MLE reduced peak responses of blood glucose significantly in both GK and Wistar rats (P glucose-loading, MLE also significantly reduced blood glucose concentrations, measured at 30 min, in both animal models (P glucose transport by MLE. Next, dried mulberry leaf powder (MLP) was administered for 8 weeks by inclusion in the diet. By MLP administration, fasting blood glucose was significantly reduced at weeks 4 and 5 (P rats. Insulin, HOMA-IR, C-reactive protein, and triglycerides tended to be decreased by MLP treatment in GK rats. All other biochemical parameters were not changed by MLP administration in GK rats. Collectively, these findings support that MLE has significant postprandial hypoglycemic effect in both non-obese diabetic and healthy animals, which may be beneficial as food supplement to manage postprandial blood glucose. Inhibitions of glucose transport as well as alpha-glucosidase in the small intestine were suggested as possible mechanisms related with the postprandial hypoglycemic effect of MLE.

  8. Moringa oleifera Root Induces Cancer Apoptosis more Effectively than Leave Nanocomposites and Its Free Counterpart

    Science.gov (United States)

    Abd-Rabou, Ahmed A; Abdalla, Aboelfetoh M; Ali, Naglaa A; Zoheir, Khairy MA

    2017-01-01

    Medicinal plants are important elements of indigenous medical system that have persisted in developing countries. Many of the botanical chemo-preventions currently used as potent anticancer agents. However, some important anticancer agents are still extracted from plants because they cannot be synthesized chemically on a commercial scale due to their complex structures that often contain several chiral centers. The aim of this study was to test different extracts from the Moringa oleifera leaves (ML), its PLGA-CS-PEG nanocomposites (MLn), as well as root core (Rc) and outer (Ro) parts for activity against hepatocarcinoma HepG2, breast MCF7, and colorectal HCT 116/ Caco-2 cells in vitro. Nano-composites were prepared and characterized. Then, the nanocomposites and the free counterparts were screened on different propagated cancer cell lines. The underlying cytotoxic impact was followed using apoptosis measurements. All extracts kill the different cancer cells with different ratios, but intriguingly, the root core extract could kill the majority of cancer cells (approximately 70-80%), while sparing normal BHK-21 cells with minimal inhibitory effect (approximately 30-40%). Apoptotic cell increment came to confirm the cytotoxic effects of these extracts on HCT 116 cells (Rc: 212% and Ro: 180%, respectively) and HepG2 cells (ML: 567.5% and MLn: 608%, respectively) compared to control (100%) mechanistically wise. Moringa oleifera nanocomposites may have potential for use as a natural source of anti-cancer compounds. PMID:28843248

  9. The cocoon emission - an electromagnetic counterpart to gravitational waves from neutron star mergers

    Science.gov (United States)

    Gottlieb, Ore; Nakar, Ehud; Piran, Tsvi

    2018-01-01

    Short gamma-ray bursts are believed to arise from compact binary mergers (either neutron star-neutron star or black hole-neutron star). If so, their jets must penetrate outflows that are ejected during the merger. As a jet crosses the ejecta, it dissipates its energy, producing a hot cocoon that surrounds it. We present here 3D numerical simulations of jet propagation in mergers' outflows, and we calculate the resulting emission. This emission consists of two components: the cooling emission, the leakage of the thermal energy of the hot cocoon, and the cocoon macronova that arises from the radioactive decay of the cocoon's material. This emission gives a brief (∼1 h) blue, wide angle signal. While the parameters of the outflow and jet are uncertain, for the configurations we have considered, the signal is bright (∼-14 to -15 absolute magnitude) and outshines all other predicted ultraviolet-optical signals. The signal is brighter when the jet breakout time is longer, and its peak brightness does not depend strongly on the highly uncertain opacity. A rapid search for such a signal is a promising strategy to detect an electromagnetic merger counterpart. A detected candidate could be then followed by deep infrared searches for the longer but weaker macronova arising from the rest of the ejecta.

  10. “The Scum of the Earth”? Foreign People Smugglers and Their Local Counterparts in Indonesia

    Directory of Open Access Journals (Sweden)

    Antje Missbach

    2011-01-01

    Full Text Available Since 2008, the number of asylum seekers and refugees trying to reach Australia from Indonesia by boat has increased. With many of them hailing from conflict-ridden countries such as Afghanistan, Iraq and Sri Lanka, most entered Indonesia with short-term tourist visas or fraudulent papers or no documents at all. It is widely known that a significant number of these ‘irregular’ migrants pay various types of brokers (often labelled, accurately or otherwise, ‘human smugglers’ at least at one stage – either to enter the country or to escape it. As a non-signatory to the UN Refugee Convention, Indonesia does not permit local integration. While a substantial part of these migrants are detained in the 13 immigration detention centres scattered around the archipelago, many roam freely, looking for opportunities for onward migration. Due to the restrictive border protection arrangements between Australia and Indonesia and a number of bilateral intelligence measures for deterring ‘unwanted’ migrants, human smugglers have been gradually forced to adapt strategies, routes and prices. According to much of the available data, most human smugglers are not Indonesians but foreigners who have been lingering in Indonesia for many years. This article demonstrates, moreover, that these foreigners depend upon local contacts to successfully carry out their risky business. Most often, the Indonesian counterparts are solely facilitators or handymen, but in a number of cases Indonesian authorities have also been involved in this highly lucrative business.

  11. AT 2017gfo: An Anisotropic and Three-component Kilonova Counterpart of GW170817

    Science.gov (United States)

    Perego, Albino; Radice, David; Bernuzzi, Sebastiano

    2017-12-01

    The detection of a kilo/macronova electromagnetic counterpart (AT 2017gfo) of the first gravitational-wave signal compatible with the merger of two neutron stars (GW170817) has confirmed the occurrence of r-process nucleosynthesis in this kind of event. The blue and red components of AT 2017gfo have been interpreted as the signature of multi-component ejecta in the merger dynamics. However, the explanation of AT 2017gfo in terms of the properties of the ejecta and of the ejection mechanisms is still incomplete. In this work, we analyze AT 2017gfo with a new semi-analytic model of kilo/macronova inferred from general-relativistic simulations of the merger and long-term numerical models of the merger aftermath. The model accounts for the anisotropic emission from the three known mass ejecta components: dynamic, winds, and secular outflows from the disk. The early multi-band light curves of AT 2017gfo can only be explained by the presence of a relatively low-opacity component of the ejecta at high latitudes. This points to the key role of weak interactions in setting the ejecta properties and determining the nucleosynthetic yields. Our model also constrains the total ejected mass associated to AT 2017gfo to be between 0.042 and 0.077 {M}⊙ , the observation angle of the source to be between π /12 and 7π /36, and the mass of the disk to be ≳ 0.08 {M}⊙ .

  12. J-GEM observations of an electromagnetic counterpart to the neutron star merger GW170817

    Science.gov (United States)

    Utsumi, Yousuke; Tanaka, Masaomi; Tominaga, Nozomu; Yoshida, Michitoshi; Barway, Sudhanshu; Nagayama, Takahiro; Zenko, Tetsuya; Aoki, Kentaro; Fujiyoshi, Takuya; Furusawa, Hisanori; Kawabata, Koji S.; Koshida, Shintaro; Lee, Chien-Hsiu; Morokuma, Tomoki; Motohara, Kentaro; Nakata, Fumiaki; Ohsawa, Ryou; Ohta, Kouji; Okita, Hirofumi; Tajitsu, Akito; Tanaka, Ichi; Terai, Tsuyoshi; Yasuda, Naoki; Abe, Fumio; Asakura, Yuichiro; Bond, Ian A.; Miyazaki, Shota; Sumi, Takahiro; Tristram, Paul J.; Honda, Satoshi; Itoh, Ryosuke; Itoh, Yoichi; Kawabata, Miho; Morihana, Kumiko; Nagashima, Hiroki; Nakaoka, Tatsuya; Ohshima, Tomohito; Takahashi, Jun; Takayama, Masaki; Aoki, Wako; Baar, Stefan; Doi, Mamoru; Finet, Francois; Kanda, Nobuyuki; Kawai, Nobuyuki; Kim, Ji Hoon; Kuroda, Daisuke; Liu, Wei; Matsubayashi, Kazuya; Murata, Katsuhiro L.; Nagai, Hiroshi; Saito, Tomoki; Saito, Yoshihiko; Sako, Shigeyuki; Sekiguchi, Yuichiro; Tamura, Yoichi; Tanaka, Masayuki; Uemura, Makoto; Yamaguchi, Masaki S.

    2017-12-01

    GW170817 is the first detected gravitational wave source from a neutron star merger. We present the Japanese collaboration for gravitational-wave electro-magnetic (J-GEM) follow-up observations of SSS17a, an electromagnetic counterpart of GW170817. SSS17a shows a 2.5 mag decline in the z band during the period between 1.7 and 7.7 d after the merger. Such a rapid decline is not comparable with supernovae light curves at any epoch. The color of SSS17a also evolves rapidly and becomes redder during later epochs: the z - H color has changed by approximately 2.5 mag during the period between 0.7 and 7.7 d. The rapid evolutions of both the color and the optical brightness are consistent with the expected properties of a kilonova that is powered by the radioactive decay of newly synthesized r-process nuclei. Kilonova models with Lanthanide elements can reproduce the aforementioned observed properties well, which suggests that r-process nucleosynthesis beyond the second peak takes place in SSS17a. However, the absolute magnitude of SSS17a is brighter than the expected brightness of the kilonova models with an ejecta mass of 0.01 M⊙, which suggests a more intense mass ejection (˜0.03 M⊙) or possibly an additional energy source.

  13. Smart Radio - Building Music Radio On the Fly

    OpenAIRE

    Hayes, Conor; Cunningham, Padraig

    2000-01-01

    This paper describes the development of a networked music application at Trinity College Dublin. Smart Radio is a web based client-server application which uses streaming audio technology and collaborative recommendation techniques to allow users build, manage and share music programmes. While it is generally acknowledged that music distribution over the web will dramatically change how the music industry operates, there are few prototypes available to demonstrate how thi...

  14. Net ground speed of downstream migrating radio-tagged Atlantic salmon ( Salmo salar L.) and brown trout ( Salmo trutta L.) smolts in relation to environmental factors

    DEFF Research Database (Denmark)

    Aarestrup, Kim; Nielsen, C.; Koed, Anders

    2002-01-01

    tagged and released in the Danish River Lilleaa. The downstream migration of the different groups of fish was monitored by manual tracking and by three automatic listening stations. The downstream migration of radio tagged smolts of both species occurred concurrently with their untagged counterparts......The downstream migration of Atlantic salmon (Salmo salar L.) and sea trout smolt (S. trutta L.) was investigated using radio telemetry in the spring of 1999 and 2000. Forty wild sea trout smolts, 20 F1 sea trout smolts, 20 hatchery salmon smolts and 20 salmon smolts from river stockings were radio....... The diel migration pattern of the radio tagged smolts was predominantly nocturnal in both species. Wild sea trout smolt migrated significantly faster than both the F1 trout and the introduced salmon. There was no correlation between net ground speed, gill Na+, K+-ATPase activity or fish length in any...

  15. 47 CFR 95.201 - (R/C Rule 1) What is the Radio Control (R/C) Radio Service?

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false (R/C Rule 1) What is the Radio Control (R/C) Radio Service? 95.201 Section 95.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio Service General...

  16. NNDSS - Table III. Tuberculosis

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table III. Tuberculosis - 2017.This Table includes total number of cases reported in the United States, by region and by states, in accordance with the...

  17. Pseudo Class III malocclusion

    National Research Council Canada - National Science Library

    Al-Hummayani, Fadia M

    2016-01-01

    .... This case report represents a none traditional treatment modality to treat deep anterior crossbite in an adult pseudo class III malocclusion complicated by severely retruded, supraerupted upper and lower incisors...

  18. Radio Frequency Power Load and Associated Method

    Science.gov (United States)

    Srinivasan, V. Karthik (Inventor); Freestone, Todd M. (Inventor); Sims, William Herbert, III (Inventor)

    2014-01-01

    A radio frequency power load and associated method. A radio frequency power load apparatus may include a container with an ionized fluid therein. The apparatus may include one conductor immersed in a fluid and another conductor electrically connected to the container. A radio frequency transmission system may include a radio frequency transmitter, a radio frequency amplifier connected to the transmitter and a radio frequency power load apparatus connected to the amplifier. The apparatus may include a fluid having an ion source therein, one conductor immersed in a fluid, and another conductor electrically connected to the container. A method of dissipating power generated by a radio frequency transmission system may include constructing a waveguide with ionized fluid in a container and connecting the waveguide to an amplifier of the transmission system.

  19. Propagation engineering in radio links design

    CERN Document Server

    Ghasemi, Abdollah; Ghasemi, Farshid

    2013-01-01

    Propagation Engineering in Radio Link Design covers the basic principles of radiowaves propagation in a practical manner.  This fundamental understanding enables the readers to design radio links efficiently. This book elaborates on new achievements as well as recently developed propagation models.  This is in addition to a comprehensive overview of fundamentals of propagation in various scenarios. It examines theoretical calculations, approaches and applied procedures needed for radio links design. The authors study and analysis of the main propagation phenomena and its mechanisms based on the recommendations of International Telecommunications Union, (ITU). The book has been organized in 9 chapters and examines the role of antennas and passive reflectors in radio services, propagation mechanisms related to radar, satellite, short distance, broadcasting and trans-horizon radio links, with two chapters devoted to radio noise and main  parameters of radio link design. The book presents some 278 illustration...

  20. A galactic microquasar mimicking winged radio galaxies.

    Science.gov (United States)

    Martí, Josep; Luque-Escamilla, Pedro L; Bosch-Ramon, Valentí; Paredes, Josep M

    2017-11-24

    A subclass of extragalactic radio sources known as winged radio galaxies has puzzled astronomers for many years. The wing features are detected at radio wavelengths as low-surface-brightness radio lobes that are clearly misaligned with respect to the main lobe axis. Different models compete to account for these peculiar structures. Here, we report observational evidence that the parsec-scale radio jets in the Galactic microquasar GRS 1758-258 give rise to a Z-shaped radio emission strongly reminiscent of the X and Z-shaped morphologies found in winged radio galaxies. This is the first time that such extended emission features are observed in a microquasar, providing a new analogy for its extragalactic relatives. From our observations, we can clearly favour the hydrodynamic backflow interpretation against other possible wing formation scenarios. Assuming that physical processes are similar, we can extrapolate this conclusion and suggest that this mechanism could also be at work in many extragalactic cases.

  1. Wireless Computing Architecture III

    Science.gov (United States)

    2013-09-01

    Peripherals ( USRPs ) [19] manufactured by Ettus Research, Inc. We emphasize that the modular nature of such COTS components is key to enabling a flexible...proven to be difficult to solve with COTS components such as USRPs . Thus, the main contribution of our work is a phase difference of arrival (PDOA...two COTS SDR antenna arrays (labeled and ), each consisting of six components: three USRP N-200 software-defined radios (SDRs) manufactured by

  2. Low-Γ Jets from Compact Stellar Mergers: Candidate Electromagnetic Counterparts to Gravitational Wave Sources

    Science.gov (United States)

    Lamb, Gavin P.; Kobayashi, Shiho

    2016-10-01

    Short gamma-ray bursts (GRBs) are believed to be produced by relativistic jets from mergers of neutron stars (NSs) or NSs and black-holes (BHs). If the Lorentz-factors Γ of jets from compact stellar mergers follow a similar power-law distribution to those observed for other high-energy astrophysical phenomena (e.g., blazars, active galactic nuclei), the population of jets should be dominated by low-Γ outflows. These jets will not produce prompt gamma-rays, but jet energy will be released as X-ray/optical/radio transients when they collide with the ambient medium. Using Monte Carlo simulations, we study the properties of such transients. Approximately 78% of merger jets \\lt 300 Mpc result in failed GRBs if the jet Γ follows a power-law distribution of index -1.75. X-ray/optical transients from failed GRBs will have broad distributions of their characteristics: light-curves peak {t}p˜ 0.1{--}10 days after a merger; flux peaks for X-ray {10}-6 {mJy}≲ {F}x≲ {10}-2 mJy; and optical flux peaks at 14≲ {m}g≲ 22. X-ray transients are detectable by Swift XRT, and ˜ 85 % of optical transients will be detectable by telescopes with limiting magnitude {m}g≳ 21, for well localized sources on the sky. X-ray/optical transients are followed by radio transients with peak times narrowly clustered around {t}p˜ 10 days, and peak flux of ˜10-100 mJy at 10 GHz and ˜0.1 mJy at 150 MHz. By considering the all-sky rate of short GRBs within the LIGO/Virgo range, the rate of on-axis orphan afterglows from failed GRBs should be 2.6(26) per year for NS-NS(NS-BH) mergers, respectively. Since merger jets from gravitational-wave (GW) trigger events tend to be directed to us, a significant fraction of GW events could be associated with the on-axis orphan afterglow.

  3. Spitzer mid-IR spectroscopy of powerful 2Jy and 3CRR radio galaxies. II. AGN power indicators and unification

    Energy Technology Data Exchange (ETDEWEB)

    Dicken, D. [CEA-Saclay, F-91191 Gif-sur-Yvette (France); Tadhunter, C. [University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Morganti, R. [ASTRON, P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Axon, D.; Robinson, A.; Magagnoli, M. [Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States); Kharb, P. [Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560034 (India); Ramos Almeida, C. [Instituto de Astrofisica de Canarias (IAC), C/V ia Lactea, s/n, E-38205 La Laguna, Tenerife (Spain); Mingo, B. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Hardcastle, M. [School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Nesvadba, N. P. H.; Singh, V. [Institut d' Astrophysique Spatiale, CNRS, Université Paris Sud, F-91405 Orsay (France); Kouwenhoven, M. B. N. [Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Haidian Qu, Beijing 100871 (China); Rose, M.; Spoon, H. [224 Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States); Inskip, K. J. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Holt, J., E-mail: daniel.dicken@cea.fr [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)

    2014-06-20

    It remains uncertain which continuum and emission line diagnostics best indicate the bolometric powers of active galactic nuclei (AGNs), especially given the attenuation caused by the circumnuclear material and the possible contamination by components related to star formation. Here we use mid-IR spectra along with multiwavelength data to investigate the merit of various diagnostics of AGN radiative power, including the mid-IR [Ne III] λ25.89 μm and [O IV] λ25.89 μm fine-structure lines, the optical [O III] λ5007 forbidden line, and mid-IR 24 μm, 5 GHz radio, and X-ray continuum emission, for complete samples of 46 2Jy radio galaxies (0.05 < z < 0.7) and 17 3CRR FRII radio galaxies (z < 0.1). We find that the mid-IR [O IV] line is the most reliable indicator of AGN power for powerful radio-loud AGNs. By assuming that the [O IV] is emitted isotropically, and comparing the [O III] and 24 μm luminosities of the broad- and narrow-line AGNs in our samples at fixed [O IV] luminosity, we show that the [O III] and 24 μm emission are both mildly attenuated in the narrow-line compared to the broad-line objects by a factor of ≈2. However, despite this attenuation, the [O III] and 24 μm luminosities are better AGN power indicators for our sample than either the 5 GHz radio or the X-ray continuum luminosities. We also detect the mid-IR 9.7 μm silicate feature in the spectra of many objects but not ubiquitously: at least 40% of the sample shows no clear evidence for these features. We conclude that, for the majority of powerful radio galaxies, the mid-IR lines are powered by AGN photoionization.

  4. Tribological responses of the WC/a-C film to sliding against different counterparts in air, water and oil

    Science.gov (United States)

    Sun, Shangqi; Wang, Yongxin; Ye, Yuwei; Liu, Xiang; Lu, Xia; Li, Jinlong

    2017-10-01

    The WC/a-C film prepared using a reactive magnetron sputtering system was investigated. The film structure and properties were characterized, and the friction response mechanism between this film and several counterparts was investigated under different environments. The hardness and surface roughness of the counterpart as well as the match between the properties of the counterpart and the film were identified as factors that play a critical role in the friction behaviour. The environment affected the extent of wear through physical and chemical reactions, and mechanical wear with friction chemical reactions was found to be the major mechanism of influence. This study is of great practical interest, as it will help to extend the service life of WC/a-C films and minimize loss during the initial running-in period.

  5. Search for High-Confidence Blazar Candidates and Their MWL Counterparts in the Fermi-LAT Catalog Using Machine Learning

    Directory of Open Access Journals (Sweden)

    Sabrina Einecke

    2016-08-01

    Full Text Available A large fraction of the gamma-ray sources presented in the Third Fermi-LAT source catalog (3FGL is affiliated with counterparts and source types, but 1010 sources remain unassociated and 573 sources are associated with active galaxies of uncertain type. The purpose of this study is to assign blazar classes to these unassociated and uncertain sources, and to link counterparts to the unassociated. A machine learning algorithm is used for the classification, based on properties extracted from the 3FGL, an infrared and an X-ray catalog. To estimate the reliability of the classification, performance measures are considered through validation techniques. The classification yielded purity values around 90% with efficiency values of roughly 50%. The prediction of high-confidence blazar candidates has been conducted successfully, and the possibility to link counterparts in the same procedure has been proven. These findings confirm the relevance of this novel multiwavelength approach.

  6. Precision Geodesy via Radio Interferometry.

    Science.gov (United States)

    Hinteregger, H F; Shapiro, I I; Robertson, D S; Knight, C A; Ergas, R A; Whitney, A R; Rogers, A E; Moran, J M; Clark, T A; Burke, B F

    1972-10-27

    Very-long-baseline interferometry experiments, involving observations of extragalactic radio sources, were performed in 1969 to determine the vector separations between antenna sites in Massachusetts and West Virginia. The 845.130-kilometer baseline was estimated from two separate experiments. The results agreed with each other to within 2 meters in all three components and with a special geodetic survey to within 2 meters in length; the differences in baseline direction as determined by the survey and by interferometry corresponded to discrepancies of about 5 meters. The experiments also yielded positions for nine extragalactic radio sources, most to within 1 arc second, and allowed the hydrogen maser clocks at the two sites to be synchronized a posteriori with an uncertainty of only a few nanoseconds.

  7. OPTICAL SPECTRA OF CANDIDATE INTERNATIONAL CELESTIAL REFERENCE FRAME (ICRF) FLAT-SPECTRUM RADIO SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Titov, O.; Stanford, Laura M. [Geoscience Australia, P.O. Box 378, Canberra, ACT 2601 (Australia); Johnston, Helen M.; Hunstead, Richard W. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Pursimo, T. [Nordic Optical Telescope, Nordic Optical Telescope Apartado 474E-38700 Santa Cruz de La Palma, Santa Cruz de Tenerife (Spain); Jauncey, David L. [CSIRO Astronomy and Space Science, ATNF and Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Maslennikov, K. [Central Astronomical Observatory at Pulkovo, Pulkovskoye Shosse, 65/1, 196140, St. Petersburg (Russian Federation); Boldycheva, A., E-mail: oleg.titov@ga.gov.au [Ioffe Physical Technical Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021 (Russian Federation)

    2013-07-01

    Continuing our program of spectroscopic observations of International Celestial Reference Frame (ICRF) sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58 m European Southern Observatory New Technology Telescope, the two 8.2 m Gemini telescopes, the 2.5 m Nordic Optical Telescope (NOT), and the 6.0 m Big Azimuthal Telescope of the Special Astrophysical Observatory in Russia. The targets were selected from the International VLBI Service for Geodesy and Astrometry candidate International Celestial Reference Catalog which forms part of an observational very long baseline interferometry (VLBI) program to strengthen the celestial reference frame. We obtained spectra of the potential optical counterparts of more than 150 compact flat-spectrum radio sources, and measured redshifts of 120 emission-line objects, together with 19 BL Lac objects. These identifications add significantly to the precise radio-optical frame tie to be undertaken by Gaia, due to be launched in 2013, and to the existing data available for analyzing source proper motions over the celestial sphere. We show that the distribution of redshifts for ICRF sources is consistent with the much larger sample drawn from Faint Images of the Radio Sky at Twenty cm (FIRST) and Sloan Digital Sky Survey, implying that the ultra-compact VLBI sources are not distinguished from the overall radio-loud quasar population. In addition, we obtained NOT spectra for five radio sources from the FIRST and NRAO VLA Sky Survey catalogs, selected on the basis of their red colors, which yielded three quasars with z > 4.

  8. The High-redshift Clusters Occupied by Bent Radio AGN (COBRA) Survey: The Spitzer Catalog

    Science.gov (United States)

    Paterno-Mahler, R.; Blanton, E. L.; Brodwin, M.; Ashby, M. L. N.; Golden-Marx, E.; Decker, B.; Wing, J. D.; Anand, G.

    2017-07-01

    We present 190 galaxy cluster candidates (most at high redshift) based on galaxy overdensity measurements in the Spitzer/IRAC imaging of the fields surrounding 646 bent, double-lobed radio sources drawn from the Clusters Occupied by Bent Radio AGN (COBRA) Survey. The COBRA sources were chosen as objects in the Very Large Array FIRST survey that lack optical counterparts in the Sloan Digital Sky Survey to a limit of m r = 22, making them likely to lie at high redshift. This is confirmed by our observations: the redshift distribution of COBRA sources with estimated redshifts peaks near z = 1 and extends out to z≈ 3. Cluster candidates were identified by comparing our target fields to a background field and searching for statistically significant (≥slant 2σ ) excesses in the galaxy number counts surrounding the radio sources; 190 fields satisfy the ≥slant 2σ limit. We find that 530 fields (82.0%) have a net positive excess of galaxies surrounding the radio source. Many of the fields with positive excesses but below the 2σ cutoff are likely to be galaxy groups. Forty-one COBRA sources are quasars with known spectroscopic redshifts, which may be tracers of some of the most distant clusters known.

  9. Software defined radio for GPS

    OpenAIRE

    Solé Gaset, Marc

    2009-01-01

    Projecte realitzat en col.laboració amb el centre Centre Tecnològic de Telecomunicacions de Catalunya (CTTC) This project describes the implementation of a software defined radio (SDR) Global Navigation Satellite System (GNSS) receiver completely real-time. The receiver is based on Global Positioning System (GPS) L1 C/A receiver. Also, the project describes the implementation and shows the improvement of a Double Delta Correlator (DDDLL) respect a typical Delay Locked Loop (DLL) of a re...

  10. LEP Radio Frequency Copper Cavity

    CERN Document Server

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  11. Radio sciences and disaster management

    Science.gov (United States)

    Tanzi, Tullio Joseph; Lefeuvre, François

    2010-01-01

    Radio communication and observation services are critical at all levels of disaster management. Among the programmes to be introduced to reduce the impact of natural and human induced disasters, potential transfers from basic research in radio science to research in disaster management are examined. Two specific aspects are studied: (i) the transfer of image processing techniques, developed in other contexts, to risk management; and (ii) the use of knowledge gathered on the effects of variations in the space environment on trans-ionospheric propagation, to gauge the interest of integrating those effects into the exploitation of communications and observation systems. Four families of image processing techniques are shown to be particularly useful to the disaster manager: zoning, counting of objects, roads and network detection, and damage assessment resulting from a series of different radiometric and geometric methods. A brief review of the effects of ionospheric variations on radio propagation up to a few GHz shows both the potential impacts of those variations on communication systems and the importance of introducing ionospheric corrections into several observation services.

  12. Workshop on Radio Recombination Lines

    CERN Document Server

    1980-01-01

    Since their first detection 15 years ago, radio recombination lines from several elements have been observed in a wide variety of objects including HII regions, planetary nebulae, molecular clouds, the diffuse interstellar medium, and recently, other galaxies. The observations span almost the entire range from 0.1 to 100 GHz, and employ both single­ djsh and aperture synthesis techniques. The theory of radio recombination lines has also advanced strongly, to the point where it is perhaps one of the best-understood in astro­ physics. In a parallel development, it has become possible over the last decade to study these same highly-excited atoms in the laboratory; this work provides further confirmation of the theoretical framework. However there has been continuing controversy over the astrophysical interpre­ tation of radio recombination line observations, especially regarding the role of stimulated emission. A workshop was held in Ottawa on 24-25 August, 1979, bringing together many of the active scientist...

  13. Quantification of urinary metabolites of principle superior counterpart of benzene; Dosage des metabolites urinaires des principaux homologues superieurs du benzene

    Energy Technology Data Exchange (ETDEWEB)

    Ruetsch, O. [CEA Centre d`Etudes de Fontenay-aux-Roses, 92 (France). Dept. de Protection de la Sante de l`Homme et de Dosimetrie]|[Lille-2 Univ., 59 (France)

    1997-12-31

    In the aim of a medical surveillance of personnel exposed to superior counterpart of benzene, it is advisable to measure in urines, the hippuric, methyl hippuric and mandelic acids, as respective biological indicators of exposure to toluene, to xylenes and styrene (chapter 1). In a first time, we give some generalities on principal superior counterparts of benzene and about the biological surveillance of workers exposed to these products. Then, we present the quantification of their urinary metabolites, as it has be done in the stage. (N.C.)

  14. Independent introductions and admixtures have contributed to adaptation of European maize and its American counterparts.

    Directory of Open Access Journals (Sweden)

    Jean-Tristan Brandenburg

    2017-03-01

    Full Text Available Through the local selection of landraces, humans have guided the adaptation of crops to a vast range of climatic and ecological conditions. This is particularly true of maize, which was domesticated in a restricted area of Mexico but now displays one of the broadest cultivated ranges worldwide. Here, we sequenced 67 genomes with an average sequencing depth of 18x to document routes of introduction, admixture and selective history of European maize and its American counterparts. To avoid the confounding effects of recent breeding, we targeted germplasm (lines directly derived from landraces. Among our lines, we discovered 22,294,769 SNPs and between 0.9% to 4.1% residual heterozygosity. Using a segmentation method, we identified 6,978 segments of unexpectedly high rate of heterozygosity. These segments point to genes potentially involved in inbreeding depression, and to a lesser extent to the presence of structural variants. Genetic structuring and inferences of historical splits revealed 5 genetic groups and two independent European introductions, with modest bottleneck signatures. Our results further revealed admixtures between distinct sources that have contributed to the establishment of 3 groups at intermediate latitudes in North America and Europe. We combined differentiation- and diversity-based statistics to identify both genes and gene networks displaying strong signals of selection. These include genes/gene networks involved in flowering time, drought and cold tolerance, plant defense and starch properties. Overall, our results provide novel insights into the evolutionary history of European maize and highlight a major role of admixture in environmental adaptation, paralleling recent findings in humans.

  15. Life-cycle Analysis of Bioproducts and Their Conventional Counterparts in GREET

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Adom, Felix [Argonne National Lab. (ANL), Argonne, IL (United States); Sather, Norm [Argonne National Lab. (ANL), Argonne, IL (United States); Han, Jeongwoo [Argonne National Lab. (ANL), Argonne, IL (United States); Snyder, Seth [Argonne National Lab. (ANL), Argonne, IL (United States); He, Chang [Northwestern Univ., Evanston, IL (United States); Gong, Jian [Northwestern Univ., Evanston, IL (United States); Yue, Dajun [Northwestern Univ., Evanston, IL (United States); You, Fengqi [Northwestern Univ., Evanston, IL (United States)

    2015-09-01

    To further expand upon the literature in this field and to develop a platform for bioproduct LCA, we developed LCA results for ten bioproducts produced either from algal glycerol or from corn stover-derived sugars. We used Argonne National Laboratory’s Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREETTM) model as the platform for this study. The data and calculations reported herein are available to GREET users in a bioproducts module included in the fall 2015 GREET release. This report documents our approach to this analysis and the results. In Chapter 2, we review the process we underwent to select the bioproducts for analysis based on market and technology readiness criteria. In Chapter 3, we review key parameters for production of the two feedstocks we considered: corn stover and algae. Given the lack of publicly available information about the production of bioproducts, which is caused in large part by the emerging nature of the industry, we developed Aspen Plus® simulations of the processes that could be used to produce each bioproduct. From these simulations, we extracted the energy and material flows of these processes, which were important inputs to the GREET bioproducts module. Chapter 4 provides the details of these Aspen Plus simulations. It is important to compare the LCA results for bioproducts to those for their petroleum counterparts. We therefore also developed material and energy flow data for conventional products based mostly on the literature. These data are described in Chapter 5 and are also included in the GREET bioproducts module. In Chapter 6, we present results from this analysis and examine areas for refinement and future research.

  16. Molecular characteristics of malignant ovarian germ cell tumors and comparison with testicular counterparts: implications for pathogenesis.

    Science.gov (United States)

    Kraggerud, Sigrid Marie; Hoei-Hansen, Christina E; Alagaratnam, Sharmini; Skotheim, Rolf I; Abeler, Vera M; Rajpert-De Meyts, Ewa; Lothe, Ragnhild A

    2013-06-01

    This review focuses on the molecular characteristics and development of rare malignant ovarian germ cell tumors (mOGCTs). We provide an overview of the genomic aberrations assessed by ploidy, cytogenetic banding, and comparative genomic hybridization. We summarize and discuss the transcriptome profiles of mRNA and microRNA (miRNA), and biomarkers (DNA methylation, gene mutation, individual protein expression) for each mOGCT histological subtype. Parallels between the origin of mOGCT and their male counterpart testicular GCT (TGCT) are discussed from the perspective of germ cell development, endocrinological influences, and pathogenesis, as is the GCT origin in patients with disorders of sex development. Integrated molecular profiles of the 3 main histological subtypes, dysgerminoma (DG), yolk sac tumor (YST), and immature teratoma (IT), are presented. DGs show genomic aberrations comparable to TGCT. In contrast, the genome profiles of YST and IT are different both from each other and from DG/TGCT. Differences between DG and YST are underlined by their miRNA/mRNA expression patterns, suggesting preferential involvement of the WNT/β-catenin and TGF-β/bone morphogenetic protein signaling pathways among YSTs. Characteristic protein expression patterns are observed in DG, YST and IT. We propose that mOGCT develop through different developmental pathways, including one that is likely shared with TGCT and involves insufficient sexual differentiation of the germ cell niche. The molecular features of the mOGCTs underline their similarity to pluripotent precursor cells (primordial germ cells, PGCs) and other stem cells. This similarity combined with the process of ovary development, explain why mOGCTs present so early in life, and with greater histological complexity, than most somatic solid tumors.

  17. Reversal of functional disorders by aspiration, expiration and cough reflexes and their voluntary counterparts

    Directory of Open Access Journals (Sweden)

    Zoltan eTomori

    2012-12-01

    Full Text Available Agonal gasping provoked by asphyxia can save ~15% of mammals even from untreated ventricular fibrillation, but it fails to revive infants with sudden infant death syndrome. Our systematic study of airway reflexes in cats and other animals indicated that in addition to cough, there are 2 distinct airway reflexes that may contribute to auto-resuscitation. Gasp- and sniff-like spasmodic inspirations can be elicited by nasopharyngeal stimulation, strongly activating the brainstem generator for inspiration, which is also involved in the control of gasping. This aspiration reflex (AspR is characterized by spasmodic inspiration without subsequent active expiration and can be elicited during agonal gasping, caused by brainstem trans-sections in cats. Stimulation of the larynx can activate the generator for expiration to evoke the expiration reflex, manifesting with prompt expiration without preceding inspiration. Stimulation of the oro-pharynx and lower airways provokes the cough reflex which results from activating of both generators. The powerful potential of the AspR resembling auto-resuscitation by gasping can influence the control mechanisms of vital functions, mediating reversal of various functional disorders.The AspR in cats interrupted hypoxic apnea, laryngo- and bronchospasm, apneusis and even transient asphyxic coma, and can normalize various hypo- and hyper-functional disorders. Introduction of a nasogastric catheter evoked similar spasmodic inspirations in premature infants and interrupted hiccough attacks in adults. Coughing on demand can prevent anaphylactic shock and resuscitate the pertinent subject. Sniff representing nasal inspiratory pressure and maximal inspiratory and expiratory pressures are voluntary counterparts of airway reflexes, and are useful for diagnosis and therapy of various cardio-respiratory and neuromuscular disorders.

  18. Energetic particle counterparts for geomagnetic pulsations of Pc1 and IPDP types

    Directory of Open Access Journals (Sweden)

    T. A. Yahnina

    2003-12-01

    Full Text Available Using the low-altitude NOAA satellite particle data, we study two kinds of localised variations of energetic proton fluxes at low altitude within the anisotropic zone equatorward of the isotropy boundary. These flux variation types have a common feature, i.e. the presence of precipitating protons measured by the MEPED instrument at energies more than 30 keV, but they are distinguished by the fact of the presence or absence of the lower-energy component as measured by the TED detector on board the NOAA satellite. The localised proton precipitating without a low-energy component occurs mostly in the morning-day sector, during quiet geomagnetic conditions, without substorm injections at geosynchronous orbit, and without any signatures of plasmaspheric plasma expansion to the geosynchronous distance. This precipitation pattern closely correlates with ground-based observations of continuous narrow-band Pc1 pulsations in the frequency range 0.1–2 Hz (hereafter Pc1. The precipitation pattern containing the low energy component occurs mostly in the evening sector, under disturbed geomagnetic conditions, and in association with energetic proton injections and significant increases of cold plasma density at geosynchronous orbit. This precipitation pattern is associated with geomagnetic pulsations called Intervals of Pulsations with Diminishing Periods (IPDP, but some minor part of the events is also related to narrow-band Pc1. Both Pc1 and IPDP pulsations are believed to be the electromagnetic ion-cyclotron waves generated by the ion-cyclotron instability in the equatorial plane. These waves scatter energetic protons in pitch angles, so we conclude that the precipitation patterns studied here are the particle counterparts of the ion-cyclotron waves.Key words. Ionosphere (particle precipitation – Magnetospheric physics (energetic particles, precipitating – Space plasma physics (wave-particle interactions

  19. Tumour necrosis factor and its receptor: a basic structural analysis of two counterparts.

    Science.gov (United States)

    Wiltgen, Marco; Tilz, Gernot P

    2008-08-01

    Inflammation of vessels is partially caused by tumour necrosis factor (TNF). Although the pharmacological understanding of the main inflammatory protein data is well characterised, basic structural information is rare. For this reason, we developed a method for the representation and analysis of the macromolecular interface between TNF and its receptor, enabling a better understanding of their interaction. In this paper we use structural information on the TNF-receptor complex in the protein (PDB) database as input to calculate an interface contact matrix, based on the distance between individual residues of each counterpart. The two-dimensional matrix is a plot of pairwise interactions between adjacent residues of the two chains in the protein complex. The residue names within each chain are plotted on the respective axis and an entry is made wherever two residues come into close contact. The matrix elements are annotated with physicochemical properties. The interface contact matrix is linked to a 3D visualisation of the macromolecular structure in such a way that mouse clicking on the appropriate part of the interface contact matrix highlights the corresponding residues in the 3D structure. Additionally the residues in the matrix are used to define the molecular surface at the interface. The interface contact matrix enables an overview representation of the residue distribution at the macromolecular interface and an evaluation of interfacial 'hot spots'. The selection of the residues in the interface contact matrix and the highlighting in the 3D structure allow an easy retrieval of the desired information out of the wealth of structural information. The representation with molecular surfaces shows complementary shapes. Many forms of treatment have been developed to reduce excessive TNF activity and their success is based on knowledge of the active sites of TNF. Our macromolecular interface analysis system will help us to define better receptor and acceptor

  20. Nuclear emergency plan, Part III: Bruce

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-01

    The Province of Ontario nuclear emergency plan parts I through VIII were developed pursuant to Section 8 of the Emergency Plans Act, 1983. This part III prescribes measures to be taken to deal with a nuclear emergency caused by the Bruce Nuclear Power Development. This plan deals mainly with actions at the provincial level and should be supplemented by the appropriate municipal plan from the Townships of Bruce and Kincardine and the Village of Tiverton. This document gives details on the plan data and organization and measures to be taken for internal and external notification, operations in general and for liquid emissions, and the provision of emergency information and public direction. Appendices detail response sector boundaries, alerting and lead times, outline plan and times for evacuation, the location of emergency facilities, and communications through television, radio and telephone.

  1. FERMI/LAT OBSERVATIONS OF SWIFT/BAT SEYFERT GALAXIES: ON THE CONTRIBUTION OF RADIO-QUIET ACTIVE GALACTIC NUCLEI TO THE EXTRAGALACTIC {gamma}-RAY BACKGROUND

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Stacy H.; Mushotzky, Richard F.; Reynolds, Christopher S. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Sambruna, Rita M. [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States); Davis, David S., E-mail: stacyt@astro.umd.edu [CRESST and X-ray Astrophysics Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States)

    2011-12-01

    We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and NGC 4945, which were identified in the Fermi first year catalog, are detected. Using Swift/BAT and radio 20 cm fluxes, we define a new radio-loudness parameter R{sub X,BAT} where radio-loud objects have log R{sub X,BAT} > -4.7. Based on this parameter, only radio-loud sources are detected by Fermi/LAT. An upper limit to the flux of the undetected sources is derived to be {approx}2 Multiplication-Sign 10{sup -11} photons cm{sup -2} s{sup -1}, approximately seven times lower than the observed flux of NGC 1068. Assuming a median redshift of 0.031, this implies an upper limit to the {gamma}-ray (1-100 GeV) luminosity of {approx}< 3 Multiplication-Sign 10{sup 41} erg s{sup -1}. In addition, we identified 120 new Fermi/LAT sources near the Swift/BAT Seyfert galaxies with significant Fermi/LAT detections. A majority of these objects do not have Swift/BAT counterparts, but their possible optical counterparts include blazars, flat-spectrum radio quasars, and quasars.

  2. AO Observations of Three Powerful Radio Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    de Vries, W; van Bruegel, W; Quirrenbach, A

    2002-08-01

    The host galaxies of powerful radio sources are ideal laboratories to study active galactic nuclei (AGN). The galaxies themselves are among the most massive systems in the universe, and are believed to harbor supermassive black holes (SMBH). If large galaxies are formed in a hierarchical way by multiple merger events, radio galaxies at low redshift represent the end-products of this process. However, it is not clear why some of these massive ellipticals have associated radio emission, while others do not. Both are thought to contain SMBHs, with masses proportional to the total luminous mass in the bulge. It either implies every SMBH has recurrent radio-loud phases, and the radio-quiet galaxies happen to be in the ''low'' state, or that the radio galaxy nuclei are physically different from radio-quiet ones, i.e. by having a more massive SMBH for a given bulge mass. Here we present the first results from our adaptive optics imaging and spectroscopy pilot program on three nearby powerful radio galaxies. Initiating a larger, more systematic AO survey of radio galaxies (preferentially with Laser Guide Star equipped AO systems) has the potential of furthering our understanding of the physical properties of radio sources, their triggering, and their subsequent evolution.

  3. Complexes of 4-chlorophenoxyacetates of Nd(III), Gd(III) and Ho(III)

    OpenAIRE

    Ferenc, W.; Bernat, M.; Sarzyński, J.; Głuchowska, H.

    2010-01-01

    The complexes of 4-chlorophenoxyacetates of Nd(III), Gd(III) and Ho(III) have been synthesized as polycrystalline hydrated solids, and characterized by elemental analysis, spectroscopy, magnetic studies and also by X-ray diffraction and thermogravimetric measurements. The analysed complexes have the following colours: violet for Nd(III), white for Gd(III) and cream for Ho(III) compounds. The carboxylate groups bind as bidentate chelating (Ho) or bridging ligands (Nd, Gd). On heating to 1173K ...

  4. Sources of the Radio Background Considered

    Energy Technology Data Exchange (ETDEWEB)

    Singal, J.; /KIPAC, Menlo Park /Stanford U.; Stawarz, L.; /KIPAC, Menlo Park /Stanford U. /Jagiellonian U., Astron. Observ.; Lawrence, A.; /Edinburgh U., Inst. Astron. /KIPAC, Menlo Park /Stanford U.; Petrosian, V.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

    2011-08-22

    We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed level because of insufficient number of objects and total flux, although radio quiet quasars contribute at the level of at least a few percent. We conclude that the most important population for production of the background is likely ordinary starforming galaxies above redshift 1 characterized by an evolving radio far-infrared correlation, which increases toward the radio loud with redshift.

  5. Radio y cultura: una propuesta de radio ciudadana en Internet

    Directory of Open Access Journals (Sweden)

    Mauricio Andrés Álvarez-Moreno

    2015-01-01

    Full Text Available El presente artículo es resultado de la investigación para optar a título de magíster “La Peña Cultural: modelo de radio ciudadana en Internet”, realizada durante los años 2013 y 2014 para la Universidad de Medellín. En ella se realiza una exploración de la radio en Internet como plataforma con herramientas multimediales que podrían afianzar la formación de ciudadanía reflexiva por medio de contenidos de promoción cultural. De la misma manera, identifica, a partir de un rastreo de emisoras en Colombia, cómo esas herramientas –las redes sociales, podcasts, chats, canales de video y nuevas formas comunicativas– permiten la participación activa de los ciudadanos en su producción. Rescatar el uso de tecnologías que facilitan la comunicación, como la radio en Internet, para reconocer y recuperar el valor de la promoción cultural propia de un estado en aras de la formación de una ciudadanía reflexiva, es el acercamiento que se hizo a partir de la etnografía y la investigación aplicada y que ahora se expone en este artículo. Es la forma en que los ciudadanos podrían converger en un medio de comunicación para producir contenidos que fortalezcan su identidad cultural o, si se quiere, su visión de nación. Es la apuesta por establecer una alternativa a los ya tradicionales modelos, una guía para la comunidad interesada en promover una ciudadanía reflexiva del patrimonio cultural. Palabras clave

  6. A first-principles study of cementite (Fe3C and its alloyed counterparts: Elastic constants, elastic anisotropies, and isotropic elastic moduli

    Directory of Open Access Journals (Sweden)

    G. Ghosh

    2015-08-01

    Full Text Available A comprehensive computational study of elastic properties of cementite (Fe3C and its alloyed counterparts (M3C (M = Al, Co, Cr, Cu, Fe, Hf, Mn, Mo, Nb, Ni, Si, Ta, Ti, V, W, Zr, Cr2FeC and CrFe2C having the crystal structure of Fe3C is carried out employing electronic density-functional theory (DFT, all-electron PAW pseudopotentials and the generalized gradient approximation for the exchange-correlation energy (GGA. Specifically, as a part of our systematic study of cohesive properties of solids and in the spirit of materials genome, following properties are calculated: (i single-crystal elastic constants, Cij, of above M3Cs; (ii anisotropies of bulk, Young’s and shear moduli, and Poisson’s ratio based on calculated Cijs, demonstrating their extreme anisotropies; (iii isotropic (polycrystalline elastic moduli (bulk, shear, Young’s moduli and Poisson’s ratio of M3Cs by homogenization of calculated Cijs; and (iv acoustic Debye temperature, θD, of M3Cs based on calculated Cijs. We provide a critical appraisal of available data of polycrystalline elastic properties of alloyed cementite. Calculated single crystal properties may be incorporated in anisotropic constitutive models to develop and test microstructure-processing-property-performance links in multi-phase materials where cementite is a constituent phase.

  7. Aggression as a Motive for Gossip During Conflict : The Role of Power, Social Value Orientation, and Counterpart's Behavior

    NARCIS (Netherlands)

    Jeuken, E.; Beersma, B.; ten Velden, F.S.; Dijkstra, M.T.M.

    Not much is known about the motives behind the use of gossip in conflict situations. We report a laboratory experiment that examined the influence of social value orientation, counterpart's behavior, and power on the motive to use gossip for indirect aggression in a conflict situation. Results

  8. Subaru/FOCAS Optical Spectroscopy for a possible IceCube-170922A counterpart TXS 0506+056

    Science.gov (United States)

    Morokuma, Tomoki; Tanaka, Yasuyuki T.; Ohta, Kouji; Matsuoka, Yoshiki; Yamashita, Takuji; Kato, Nanako

    2017-10-01

    We performed optical spectroscopic observations on September 30 and October 1, 2017 (UT) with the 8.2-m Subaru telescope and Faint Object Camera and Spectrograph (FOCAS) for TXS 0506+056 which is a possible counterpart to the IceCube-170922A high-energy neutrino event (Tanaka et al. 2017, ATel #10791).

  9. The Effect of Counterpart Material on the Sliding Wear of TiAlN Coatings Deposited by Reactive Cathodic Pulverization

    Directory of Open Access Journals (Sweden)

    Michell Felipe Cano Ordoñez

    2015-11-01

    Full Text Available This work aims to study the effect of the counterpart materials (100Cr6, Al2O3 and WC-Co on the tribological properties of TiAlN thin films deposited on AISI H13 steel substrate by reactive magnetron co-sputtering. The structural characterization of the TiAlN films, performed by X-ray diffraction, showed (220 textured fcc crystalline structure. The values of hardness and elastic modulus obtained by nanoindentation were 27 GPa and 420 GPa, respectively, which resulted in films with a relatively high resistance to plastic deformation. Ball-on-disk sliding tests were performed using normal loads of 1 N and 3 N, and 0.10 m/s of tangential velocity. The wear coefficient of the films was determined by measuring the worn area using profilometry every 1000 cycles. The mechanical properties and the chemical stability of the counterpart material, debris formation and the contact stress influences the friction and the wear behavior of the studied tribosystems. Increasing the hardness of the counterpart decreases the coefficient of friction (COF due to lower counterpart material transference and tribofilm formation, which is able to support the contact pressure. High shear stress concentration at the coating/substrate interface was reported for higher load promoting failure of the film-substrate system for all tribopairs

  10. Post-test analysis of the ROSA/LSTF and PKL counterpart test

    Energy Technology Data Exchange (ETDEWEB)

    Carlos, S., E-mail: scarlos@iqn.upv.es [Departament d’Enginyeria Química i Nuclear, Universitat Politècnica de València, Camí de Vera, 14, València Spain (Spain); Querol, A., E-mail: anquevi@iqn.upv.es [Departament d’Enginyeria Química i Nuclear, Universitat Politècnica de València, Camí de Vera, 14, València Spain (Spain); Instituto de Seguridad Industrial, Radiofísica y Medioambiental, Universitat Politècnica de València, Camí de Vera, 14, València (Spain); Gallardo, S., E-mail: sergalbe@iqn.upv.es [Departament d’Enginyeria Química i Nuclear, Universitat Politècnica de València, Camí de Vera, 14, València Spain (Spain); Instituto de Seguridad Industrial, Radiofísica y Medioambiental, Universitat Politècnica de València, Camí de Vera, 14, València (Spain); Sanchez-Saez, F., E-mail: frasansa@etsii.upv.es [Departament d’Enginyeria Química i Nuclear, Universitat Politècnica de València, Camí de Vera, 14, València Spain (Spain); and others

    2016-02-15

    Highlights: • TRACE modelization for PKL and ROSA/LSTF installations. • Secondary-side depressurization as accident management action. • CET vs PCT relation. • Analysis of differences in the vessel models. - Abstract: Experimental facilities are scaled models of commercial nuclear power plants, and are of great importance to improve nuclear power plants safety. Thus, the results obtained in the experiments undertaken in such facilities are essential to develop and improve the models implemented in the thermal-hydraulic codes, which are used in safety analysis. The experiments and inter-comparisons of the simulated results are usually performed in the frame of international programmes in which different groups of several countries simulate the behaviour of the plant under the accidental conditions established, using different codes and models. The results obtained are compared and studied to improve the knowledge on codes performance and nuclear safety. Thus, the Nuclear Energy Agency (NEA), in the nuclear safety work area, auspices several programmes which involve experiments in different experimental facilities. Among the experiments proposed in NEA programmes, one on them consisted of performing a counterpart test between ROSA/LSTF and PKL facilities, with the main objective of determining the effectiveness of late accident management actions in a small break loss of coolant accident (SBLOCA). This study was proposed as a result of the conclusion obtained by the NEA Working Group on the Analysis and Management of Accidents, which analyzed different installations and observed differences in the measurements of core exit temperature (CET) and maximum peak cladding temperature (PCT). In particular, the transient consists of a small break loss of coolant accident (SBLOCA) in a hot leg with additional failure of safety systems but with accident management measures (AM), consisting of a fast secondary-side depressurization, activated by the CET. The paper

  11. Pregnant trauma victims experience nearly 2-fold higher mortality compared to their nonpregnant counterparts.

    Science.gov (United States)

    Deshpande, Neha A; Kucirka, Lauren M; Smith, Randi N; Oxford, Corrina M

    2017-11-01

    Trauma is the leading nonobstetric cause of death in women of reproductive age, and pregnant women in particular may be at increased risk of violent trauma. Management of trauma in pregnancy is complicated by altered maternal physiology, provider expertise, potential disparate imaging, and distorted anatomy. Little is known about the impact of trauma on maternal mortality. We sought to: (1) characterize nonviolent and violent trauma among pregnant women; (2) determine whether pregnancy is associated with increased mortality following traumatic injury; and (3) identify risk factors for trauma-related death in pregnant women. We studied 1148 trauma events among pregnant girls and women and 43,608 trauma events among nonpregnant girls and women of reproductive age (14-49 years) who presented to any accredited trauma center in Pennsylvania for treatment of trauma-related injuries from 2005 through 2015, as captured in the Pennsylvania Trauma Outcome Study. Traumas were categorized as violent (eg, homicide or assault) or nonviolent (eg, motor vehicle accident or accidental fall). We used modified Poisson regression to estimate relative rate of trauma-related death, adjusting for demographic characteristics and severity of trauma. Compared to nonpregnant women, pregnant women and girls had a lower injury severity score (8.9 vs 10.9, P victims had a 1.6-fold higher rate of mortality compared to their nonpregnant counterparts (P victims of nonviolent and violent trauma (adjusted relative risk, 1.69, P = .002, and adjusted relative risk, 1.60, P = .007, respectively). Pregnant trauma victims were less likely to undergo surgery (adjusted relative risk, 0.70, P = .001) and more likely to be transferred to another facility (adjusted relative risk, 1.72, P < .001). Even after adjusting for demographics and injury severity score, violent trauma was associated with 3.14-fold higher mortality in pregnant women and girls compared to nonviolent trauma (adjusted relative risk, 3

  12. Lutetium(III cyclotetraphosphate

    Directory of Open Access Journals (Sweden)

    Aïcha Mbarek

    2010-06-01

    Full Text Available Single crystals of the title compound, tetralutetium(III tris(cyclotetraphosphate, Lu4(P4O123, were obtained by solid-state reaction. The cubic structure is isotypic with its AlIII and ScIII analogues and is built up from four-membered (P4O124− phosphate ring anions (overline{4} symmetry, isolated from each other and further linked through isolated LuO6 octahedra (.3. symmetry via corner sharing. Each LuO6 octahedron is linked to six (P4O124− rings, while each (P4O124− ring is linked to eight LuO6 octahedra.

  13. Radio Internet dalam Perspektif Determinisme Teknologi

    Directory of Open Access Journals (Sweden)

    Aprilani Aprilani

    2011-01-01

    Full Text Available The growth of internet radio has brought a significant impact on change management and radio audiences. Marriage analog radio with internet technology into a new media (Internet Radio is seen as an alternative solution to some problems of analog radio. Instrumentalist views on Technology Determinism gives the assumption that the function of technology is very dominant in shaping society. Philosophy of technology against this assumption, because Technology Determinism can not explain the meaning and implications of technology for humans. Internet radio using technology to facilitate community access, however the implications of its use to produce new problems in the realm of economic, cultural, social and political. Understanding awareness of the use of technology is the essence of the basic form of critical consciousness of society.

  14. III-V microelectronics

    CERN Document Server

    Nougier, JP

    1991-01-01

    As is well known, Silicon widely dominates the market of semiconductor devices and circuits, and in particular is well suited for Ultra Large Scale Integration processes. However, a number of III-V compound semiconductor devices and circuits have recently been built, and the contributions in this volume are devoted to those types of materials, which offer a number of interesting properties. Taking into account the great variety of problems encountered and of their mutual correlations when fabricating a circuit or even a device, most of the aspects of III-V microelectronics, from fundamental p

  15. Problem Lokalitas dalam Bisnis Radio Network

    Directory of Open Access Journals (Sweden)

    - Rahayu

    2006-03-01

    Full Text Available The emergence of radio network has some consequencies. These relate to the ownership of the network, problems of locality and threads to democracy. Some may view that the networks have strengthened the position of radio. The others believe that the netwrok risks the local power in Indonesia. This article explores the problems of the radio networks in Indonesia, especially when dealing with the local elements.

  16. Origin of Radio Enhancements in Type II Bursts in the Outer Corona

    Science.gov (United States)

    Al-Hamadani, Firas; Pohjolainen, Silja; Valtonen, Eino

    2017-09-01

    We study interplanetary (IP) solar radio type II bursts from 2011 - 2014 in order to determine the cause of the intense enhancements in their radio emission. Type II bursts are known to be due to propagating shocks that are often associated with fast halo-type coronal mass ejections (CMEs). We analysed the radio spectral data and the white-light coronagraph data from 16 selected events to obtain directions and heights for the propagating CMEs and the type II bursts. CMEs preceding the selected events were included in the analysis to verify whether CME interaction was possible. As a result, we were able to classify the events into five different groups. 1) Events where the heights of the CMEs and type II bursts are consistent, indicating that the shock is located at the leading front of the CME. The radio enhancements are superposed on the type II lanes, and they are probably formed when the shock meets remnant material from earlier CMEs, but the shock continues to propagate at the same speed. 2) Events where the type II heights agree with the CME leading front and an earlier CME is located at a height that suggests interaction. The radio enhancements and frequency jumps could be due to the merging process of the CMEs. 3) Events where the type II heights are significantly lower than the CME heights almost from the start. Interaction with close-by streamers is probably the cause for the enhanced radio emission, which is located at the CME flank region. 4) Events where the radio enhancements are located within wide-band type II bursts and the causes for the radio enhancements are not clear. 5) Events where the radio enhancements are associated with later-accelerated particles (electron beams, observed as type III bursts) that stop at the type II burst emission lane, and no other obvious reason for the enhancement can be identified. Most of the events (38%) were due to shock-streamer interaction, while one quarter of the events was due to possible CME-CME interaction

  17. Radio

    DEFF Research Database (Denmark)

    Buhl, Hans

    2015-01-01

    Radioen blev opfundet ad flere omgange. Teknologien kom frem kort før 1900, mens det først var omkring 1. Verdenskrig, at radioen blev opfundet som massemedium. Det skete, da en opfindsom amerikaner fandt på at sende musik ud i æteren til de unge mænd, der smuglyttede til telegrammerne mellem de ...

  18. La radio universitaria se mueve

    Directory of Open Access Journals (Sweden)

    Gloria Rodríguez Garay

    2015-01-01

    Full Text Available El reto que plantea la radiodifusión universitaria en México con el intercambio productivo como sistema y procedimiento para optimizar el medio, hace necesaria la concienciación y participación activa de la comunidad universitaria; estudiantil, docente y administrativa, con el fin de valorar la producción radiofónica como elemento fundamental para el desarrollo académico de las mismas instituciones y su vinculación permanente con la sociedad. La radio universitaria cumple funciones de información, entretenimiento y vinculación social.

  19. Signal processing for cognitive radios

    CERN Document Server

    Jayaweera, Sudharman K

    2014-01-01

    This book covers power electronics, in depth, by presenting the basic principles and application details, and it can be used both as a textbook and reference book.  Introduces the specific type of CR that has gained the most research attention in recent years: the CR for Dynamic Spectrum Access (DSA). Provides signal processing solutions to each task by relating the tasks to materials covered in Part II. Specialized chapters then discuss specific signal processing algorithms required for DSA and DSS cognitive radios  

  20. HF radio systems and circuits

    CERN Document Server

    Sabin, William

    1998-01-01

    A comprehensive reference for the design of high frequency communications systems and equipment. This revised edition is loaded with practical data, much of which cannot be found in other reference books. Its approach to the subject follows the needs of an engineer from system definition and performance requirements down to the individual circuit elements that make up radio transmitters and receivers. The accompanying disk contains updated software on filters, matching networks and receiver analysis. SciTech Publishing also provides many other products related to Communication Systems Design.

  1. Radio emission of the sun and planets

    CERN Document Server

    Zheleznyakov, V V

    1970-01-01

    International Series of Monographs in Natural Philosophy, Volume 25: Radio Emission of the Sun and Planets presents the origin of the radio emission of the planets. This book examines the outstanding triumphs achieved by radio astronomy of the solar system. Comprised of 10 chapters, this volume begins with an overview of the physical conditions in the upper layers of the Sun, the Moon, and the planets. This text then examines the three characteristics of radio emission, namely, the frequency spectrum, the polarization, and the angular spectrum. Other chapters consider the measurements of the i

  2. Computing angle of arrival of radio signals

    Science.gov (United States)

    Borchardt, John J.; Steele, David K.

    2017-11-07

    Various technologies pertaining to computing angle of arrival of radio signals are described. A system that is configured for computing the angle of arrival of a radio signal includes a cylindrical sheath wrapped around a cylindrical object, where the cylindrical sheath acts as a ground plane. The system further includes a plurality of antennas that are positioned about an exterior surface of the cylindrical sheath, and receivers respectively coupled to the antennas. The receivers output measurements pertaining to the radio signal. A processing circuit receives the measurements and computes the angle of arrival of the radio signal based upon the measurements.

  3. The other radios: Alternative scenario in Peru

    Directory of Open Access Journals (Sweden)

    Carlos Rivadeneyra-Olcese

    2009-10-01

    Full Text Available Peruvian radio shows a huge diversity in direct proportion to its multiculturality, the same which shows a process full of different influences of social actor which have produced a complex and extremely rich scenario, that is also filled with opportunities and challenges. Beyond the great capital commercial radio are the other radios, small companies, provincial, from church or the mayor or small business owners sons of folkloric melomania, different actors with a passion to establish a new media. The multiple motivations produce a scenario with many types of radio that we wishes to start knowing.

  4. Radio systems engineering a tutorial approach

    CERN Document Server

    Santos, Héctor J De Los; Ponte, Juan

    2015-01-01

    This book is intended for readers who already have knowledge of devices and circuits for radio-frequency (RF) and microwave communication and are ready to study the systems engineering-level aspects of modern radio communications systems. The authors provide a general overview of radio systems with their components, focusing on the analog parts of the system and their non-idealities. Based on the physical functionality of the various building blocks of a modern radio system, block parameters are derived, which allows the examination of their influence on the overall system performance. The dis

  5. Air shower radio detection with LOPES

    Energy Technology Data Exchange (ETDEWEB)

    Bluemer, J; Apel, W D; Arteaga, J C; Badea, F; Bekk, K; Bozdog, H; Daumiller, K [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Asch, T [Inst. Prozessdatenverarbeitung und Elektronik, Forschungszentrum Karlsruhe (Germany); Auffenberg, J [Fachbereich Physik, Universitaet Wuppertal (Germany); Baehren, L; Butcher, H [ASTRON, Dwingeloo (Netherlands); Bertaina, M; Chiavassa, A [Dipartimento di Fisica Generale dell' Universita Torino (Italy); Biermann, P L [Max-Planck-Institut fuer Radioastronomie Bonn (Germany); Brancus, I M [National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Brueggemann, M; Buchholz, P [Fachbereich Physik, Universitaet Siegen (Germany); Buitink, S [Department of Astrophysics, Radboud University Nijmegen (Netherlands); Cossavella, F; Souza, V de [Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany)], E-mail: Johannes.Bluemer@ik.fzk.de (and others)

    2008-07-15

    LOPES is an array of 30 radio antenna co-located with the KASCADE-Grande extensive air shower detector in Karlsruhe, Germany. It is designed as a digital radio interferometer for the detection of radio emission from extensive air showers. LOPES features high bandwidth and fast data processing. A unique asset is the concurrent operation with KASCADE-Grande. We report about the progress in understanding the radio signals measured by LOPES. In addition, the status and further perspectives of LOPES and the large scale application of this novel detection technique are sketched.

  6. Electron cyclotron maser emission in coronal arches and solar radio type V bursts

    Energy Technology Data Exchange (ETDEWEB)

    Tang, J. F. [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, 150 Science 1-Street, Urumqi, Xinjiang 830011 (China); Wu, D. J. [Purple Mountain Observatory, CAS, Nanjing 210008 (China); Tan, C. M., E-mail: jftang@xao.ac.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2013-12-10

    Solar radio type V bursts were classified as a special spectral class based on their moderately long duration, wide bandwidth, and sense of polarization opposite of associated type III bursts. However, type V bursts are also closely related to the preceding type III bursts. They have an approximately equal source height and the same dispersion of position with frequency. Electron cyclotron maser (ECM) instability driven by beam electrons has been used to explain type III bursts in recent years. We propose ECM emission as the physical process of type V solar radio bursts. According to the observed properties of type V and III bursts, we propose that energetic electrons in excited type V continuum are trapped in coronal loops, which are adjacent to the open field lines traced by type III electrons. With the proposed magnetic field configuration and the ECM emission mechanism, the observed properties of type V bursts, such as long duration, wide bandwidth, and opposite sense of polarization can be reasonably explained by our model.

  7. The Connection between Radio Halos and Cluster Mergers and the ...

    Indian Academy of Sciences (India)

    We discuss the statistical properties of the radio halo population in galaxy clusters. Radio bi-modality is observed in galaxy clusters: a fraction of clusters host giant radio halos while a majority of clusters do not show evidence of diffuse cluster-scale radio emission. The radio bi-modality has a correspondence in terms of ...

  8. Metallothionein (MT)-III

    DEFF Research Database (Denmark)

    Carrasco, J; Giralt, M; Molinero, A

    1999-01-01

    Metallothionein-III is a low molecular weight, heavy-metal binding protein expressed mainly in the central nervous system. First identified as a growth inhibitory factor (GIF) of rat cortical neurons in vitro, it has subsequently been shown to be a member of the metallothionein (MT) gene family a...

  9. BANANAS III (ARTIC

    African Journals Online (AJOL)

    Fr. Ikenga

    Key words: Cross-Retaliation, Justiciability, EC-Bananas III, Countermeasure. 1. Introduction. The World Trade Organisation (WTO) as an international legal personality regulates the World. Trading System to ensure smooth, free, fair and predictable flow of international trade. It is. “the only International Organisation dealing ...

  10. Cobalt(III) complex

    Indian Academy of Sciences (India)

    Administrator

    . 2 radicals ... Crystal structure of the complex was determined by X-ray diffraction and is reported elsewhere. 5. The complex is stable towards hydrolysis at least for 10 h as checked by its ..... served in Co(III) aquo-ammonia complexes where.

  11. A Nonthermal Radio Filament Connected to the Galactic Black Hole?

    Science.gov (United States)

    Morris, Mark R.; Zhao, Jun-Hui; Goss, W. M.

    2017-12-01

    Using the Very Large Array, we have investigated a nonthermal radio filament (NTF) recently found very near the Galactic black hole and its radio counterpart, Sgr A*. While this NTF—the Sgr A West Filament (SgrAWF)—shares many characteristics with the population of NTFs occupying the central few hundred parsecs of the Galaxy, the SgrAWF has the distinction of having an orientation and sky location that suggest an intimate physical connection to Sgr A*. We present 3.3 and 5.5 cm images constructed using an innovative methodology that yields a very high dynamic range, providing an unprecedentedly clear picture of the SgrAWF. While the physical association of the SgrAWF with Sgr A* is not unambiguous, the images decidedly evoke this interesting possibility. Assuming that the SgrAWF bears a physical relationship to Sgr A*, we examine the potential implications. One is that Sgr A* is a source of relativistic particles constrained to diffuse along ordered local field lines. The relativistic particles could also be fed into the local field by a collimated outflow from Sgr A*, perhaps driven by the Poynting flux accompanying the black hole spin in the presence of a magnetic field threading the event horizon. Second, we consider the possibility that the SgrAWF is the manifestation of a low-mass-density cosmic string that has become anchored to the black hole. The simplest form of these hypotheses would predict that the filament be bi-directional, whereas the SgrAWF is only seen on one side of Sgr A*, perhaps because of the dynamics of the local medium.

  12. Polarized radio emission and radio wavefront shape of extensive air showers

    NARCIS (Netherlands)

    Corstanje, A.; Buitink, S.; Enriquez, J. E.; Falcke, H.; Hörandel, J. R.; Nelles, A.; Rachen, J. P.; Rossetto, L.; Schellart, P.; Scholten, O.; Ter Veen, S.; Thoudam, S.; Trinh, T. N G

    2015-01-01

    The LOFAR radio telescope located in the north of the Netherlands offers a high density of omnidirectional radio antennas. The LOFAR key science project Cosmic Rays is therefore well suited for detailed studies of the radio signal from air showers, and has been measuring since mid-2011 at primary

  13. Kothmale Community Radio Interorg Project: True Community Radio or Feel-Good Propaganda?

    Science.gov (United States)

    Harvey-Carter, Liz

    2009-01-01

    The Kothmale Community Radio and Interorg project in Sri Lanka has been hailed as an example of how a community radio initiative should function in a developing nation. However, there is some question about whether the Kothmale Community Interorg Project is a true community radio initiative that empowers local communities to access ICT services…

  14. Beamed radio and far infrared emission in quasars and radio galaxies

    NARCIS (Netherlands)

    Hoekstra, H; Barthel, PD; Hes, R

    Simple orientation model predictions for the radio to far infrared spectral energy distributions of radio-loud AGN are confronted with observations at various radio frequencies. This model is subsequently used to investigate 60 mu m far-infrared data. The results are supportive of the unified scheme

  15. Anomalous radio-loudness of Cygnus A and other powerful radio galaxies

    NARCIS (Netherlands)

    Barthel, PD; Arnaud, KA

    1996-01-01

    The nearby, extremely powerful radio galaxy Cygnus A stands out as having an atypically low far-infrared/radio luminosity ratio. It is demonstrated that in objects displaying such a low ratio the radio-loudness is anomalously high, which fact is connected to these objects inhabiting dense X-ray

  16. 76 FR 70904 - Commission Organization; Practice and Procedure; Radio Broadcast Services; and Experimental Radio...

    Science.gov (United States)

    2011-11-16

    ... COMMISSION 47 CFR Parts 0, 1, 73, and 74 Commission Organization; Practice and Procedure; Radio Broadcast Services; and Experimental Radio, Auxiliary, Special Broadcast and Other Program Distributional Services... obsolete. Section 1.805 of the Commission's rules requires common carriers engaged in public radio service...

  17. The radio spectral energy distribution of infrared-faint radio sources

    NARCIS (Netherlands)

    Herzog, A.; Norris, R. P.; Middelberg, E.; Seymour, N.; Spitler, L. R.; Emonts, B. H. C.; Franzen, T. M. O.; Hunstead, R.; Intema, H. T.; Marvil, J.; Parker, Q. A.; Sirothia, S. K.; Hurley-Walker, N.; Bell, M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Callingham, J. R.; Deshpande, A. A.; Dwarakanath, K. S.; For, B. -Q; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hindson, L.; Johnston-Hollitt, M.; Kapińska, A. D.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Oberoi, D.; Offringa, A.; Ord, S. M.; Prabu, T.; Procopio, P.; Udaya Shankar, N.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Zheng, Q.; Bannister, K. W.; Chippendale, A. P.; Harvey-Smith, L.; Heywood, I.; Indermuehle, B.; Popping, A.; Sault, R. J.; Whiting, M. T.

    2016-01-01

    Context. Infrared-faint radio sources (IFRS) are a class of radio-loud (RL) active galactic nuclei (AGN) at high redshifts (z ≥ 1.7) that are characterised by their relative infrared faintness, resulting in enormous radio-to-infrared flux density ratios of up to several thousand. Aims: Because of

  18. Effects of Class III malocclusion on young male adults' vocal tract development: a pilot study.

    Science.gov (United States)

    Xue, Steve An; Lam, Connie W-Y; Whitehill, Tara L; Samman, Nabil

    2011-03-01

    To compare the vocal tract configuration between male speakers with Class III malocclusion and their normally developing counterparts and to investigate the concomitant acoustic changes caused by the alterations in vocal tract configuration. Eight young male patients with Class III malocclusion and 8 normally developing counterparts participated in this study. Acoustic reflection technology was used to measure vocal tract dimensions in the 2 groups. A continuous speech sample and 4 sustained vowels (/a/, /æ/, /i/, and /u/) were recorded from each participant to obtain the fundamental frequency and the first 3 formant frequencies (F1, F2, and F3). The results showed significantly greater oral length and oral volume for young male patients with Class III malocclusion than their cohorts. The F1 of vowel /u/ was found to be significantly higher in male patients with Class III malocclusion than their cohorts. The vowel space of the 4 recorded vowels was reduced and the F1-F2 formant map for /u/ was relatively more scattered in male patients with Class III malocclusion than in the control speakers. This study has provided preliminary information on the effects of Class III malocclusion on vocal tract configuration and concomitant acoustic changes in young male patients. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  19. A comparison of the DSM-5 Section II and Section III personality disorder structures.

    Science.gov (United States)

    Anderson, Jaime; Snider, Stephen; Sellbom, Martin; Krueger, Robert; Hopwood, Christopher

    2014-05-30

    The DSM-5 Section III includes a hybrid model for the diagnosis of personality disorders, in which sets of dimensional personality trait facets are configured into personality disorder types. These PD types resemble the Section II categorical counterparts with dimensional traits descriptive of the Section II criteria to maintain continuity across the diagnostic systems. The current study sought to evaluate the continuity across the Section II and III models of personality disorders. This sample consisted of 397 undergraduate students, administered the Personality Inventory for the DSM-5 (Krueger et al., 2012) and the Structured Clinical Interview for the DSM-IV Axis II Disorders-Personality Questionnaire (First et al., 2013). We examined whether the DSM-5 Section III trait facets for the PDs would be associated with their respective Section II counterparts, as well as determining whether additional facets could augment the prediction of the Section II disorders. Results revealed that, generally, the DSM-5 Section II disorders were most strongly associated with their Section III traits. Results also showed evidence to support the addition of facets not included in the Section III diagnostic criteria in the prediction of most disorders. These results show general support for the Section III model of personality disorders, however, results also show that additional research is needed to replicate these findings. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Unveiling the origin of fast radio bursts by optical follow-up observations

    Science.gov (United States)

    Niino, Yuu; Totani, Tomonori; Okumura, Jun E.

    2014-12-01

    We discuss how we can detect and identify counterparts of fast radio bursts (FRBs) in future optical follow-up observations of FRBs if real-time alerts for FRBs become available. We consider kilonovae as candidates for FRB optical counterparts, as expected in the case that FRBs originate from mergers of double neutron star binaries. Although theoretical predictions on luminosities of kilonovae are still highly uncertain, recent models suggest that kilonovae can be detected at redshifts up to z ˜ 0.3 within the range of the uncertainties. We expect ˜ 1-5 unrelated supernovae (SNe) down to a similar variability magnitude in a five-day interval within the typical error radius of an FRB. We show, however, that a kilonova can be distinguished from these SNe by its rapid decay and/or color evolution, making it possible to verify the existence of a kilonova associated with an FRB. We also discuss the case that SNe Ia are FRB optical counterparts, as might be the case if FRBs originate from double white dwarf binaries. Verification of this scenario is also possible, since the chance probability of finding a SNe Ia having a consistent explosion time with that of an FRB within the FRB error region is small (typically ≲ 0.01).

  1. The Millimeter-Radio Emission of BL Lacertae During Two γ-ray Outbursts

    Science.gov (United States)

    Kim, Dae-Won; Trippe, Sascha; Lee, Sang-Sung; Park, Jong-Ho; Kim, Jae-Young; Algaba, Juan-Carlos; Hodgson, Jeffrey A.; Kino, Motoki; Zhao, Guang-Yao; Wajima, Kiyoaki; Kang, Sincheol; Oh, Junghwan; Lee, Taeseok; Byun, Do-Young; Kim, Soon-Wook; Kim, Jeong-Sook

    2017-12-01

    We present a study of the inexplicit connection between radio jet activity and γ-ray emission of BL Lacertae (BL Lac; 2200+420). We analyze the long-term millimeter activity of BL Lac via interferometric observations with the Korean VLBI Network (KVN) obtained at 22, 43, 86, and 129 GHz simultaneously over three years (from January 2013 to March 2016); during this time, two γ-ray outbursts (in November 2013 and March 2015) can be seen in γ-ray light curves obtained from Fermi observations. The KVN radio core is optically thick at least up to 86 GHz; there is indication that it might be optically thin at higher frequencies. To first order, the radio light curves decay exponentially over the time span covered by our observations, with decay timescales of 411±85 days, 352±79 days, 310±57 days, and 283±55 days at 22, 43, 86, and 129 GHz, respectively. Assuming synchrotron cooling, a cooling time of around one year is consistent with magnetic field strengths B˜2 μT and electron Lorentz factors γ˜10,000. Taking into account that our formal measurement errors include intrinsic variability and thus over-estimate the statistical uncertainties, we find that the decay timescale τ scales with frequency ν like τ∝ν^{-0.2}. This relation is much shallower than the one expected from opacity effects (core shift), but in agreement with the (sub-)mm radio core being a standing recollimation shock. We do not find convincing radio flux counterparts to the γ-ray outbursts. The spectral evolution is consistent with the `generalized shock model' of tet{valtaoja1992}. A temporary increase in the core opacity and the emergence of a knot around the time of the second γ-ray event indicate that this γ-ray outburst might be an `orphan' flare powered by the `ring of fire' mechanism.

  2. SURVEY PERILAKU MENDENGARKAN RADIO DI JAKARTA

    Directory of Open Access Journals (Sweden)

    Siti Dewi Sri Ratna Sari

    2016-05-01

    Full Text Available This research is to find out the profile of radio broadcasting’s content in Jakarta and to look for measured data as the parameter to assess radio broadcasting programs and the radio listeners profile in DKI Jakarta. The research methodology is survey with 1000 respondents as the sample with 2.24% margin of error and 95% credibility level. The sampling method used is Multistage Random Sampling from 5 out of 6 DKI Jakarta Province areas, except Thousand Islands Regency. Data collection technique used is face to face personal interview by giving gift to the respondents. Research result describes the profile of radio listeners is middle class productive age working men and women whose prime reason listening to radio is music as their pastime. Respondents are categorized as medium listeners with 1.87 hour as their average of listening to radio. Nevertheless, the prime time is covering the whole day both while they are listening at home and while they are mobile. Research found that respondents are already satisfied by the radio programs in Jakarta. The competition of radio stations in Jakarta based on their listeners is Gen FM at the top with 44.6%, followed by Bens Radio, Elshinta, I-Radio, Prambors, CBB, and so on. An interesting finding is that radio’s function to deliver social communication is fulfilled by placing religious speech and information as the second and the third most preferable programs with 9.8% and 8.0% below music program.   Penelitian ini bertujuan untuk mengetahui profil isi siaran radio yang selama ini bersiaran di Jakarta sekaligus mencari data terukur sebagai parameter untuk melakukan penilaian terhadap program isi siaran radio, termasuk pola mendengarkan radio pendengar radio seperti durasi dan tempat di provinsi DKI Jakarta. Metode penelitian berupa survei dengan sampel yang diambil sebanyak 1000 responden, margin of error 2.24% dan tingkat kepercayaan 95%. Metode pengambilan sampel dalam penelitian ini adalah dengan

  3. Radio-interferometric Neutrino Reconstruction for the Askaryan Radio Array

    Directory of Open Access Journals (Sweden)

    Lu Ming-Yuan

    2017-01-01

    Full Text Available The Askaryan Radio Array (ARA is a neutrino telescope array under phased deployment near the South Pole. The array aims to discover and determine the ultra-high energy neutrino flux via detection of the Askaryan signal from neutrino-induced showers. This novel detection channel makes ARA the most cost-effective neutrino observatory in probing the neutrino flux from 1017eV – 1019eV. This contribution will discuss an interferometric vertex reconstruction technique developed for ARA, taking into account the curved paths traveled by EM radiation in inhomogeneous ice. Preliminary results on the directional reconstruction of an in situ calibration pulser as well as simulated neutrino vertices will be presented.

  4. Serotonin impairment in CSF of PD patients, without an apparent clinical counterpart.

    Directory of Open Access Journals (Sweden)

    Enrica Olivola

    Full Text Available In Parkinson's disease (PD, several studies have detected an impaired serotonin (5-HT pathway, likely affecting both motor and non-motor domains. However, the precise impact of 5-HT impairment is far from established. Here, we have used a HPLC chromatographic method, in a homogenous cohort (n = 35 of non fluctuating, non dyskinetic PD patients, to assess the concentration of 5-HT and its metabolite 5-HIAA in peripheral cerebrospinal fluid (CSF obtained from lumbar puncture (LP. LP was performed following three days of therapy withdrawal, in order to vanish the effects of prolonged released dopamine agonists (DA, and in absence of any serotonergic agent. The PD patient group showed a significantly reduced CSF level of both 5-HT and 5-HIAA compared to either age-matched control subjects (n = 18, or Alzheimer's disease patients (n = 20. However, no correlation emerged between 5-HT/5-HIAA concentrations and UPDRS-III (r = -0.12, disease duration (r = -0.1, age (r = -0.27 and MMSE (r = 0.11. Intriguingly, low CSF 5-HT levels did not differ for gender or for motor phenotype (in terms of non-tremor dominant subtype and tremor dominant subtype. Further, low CSF 5-HT levels did not correlate with the presence of depression, apathy or sleep disturbance. Our findings support the contention that 5-HT impairment is a cardinal feature of stable PD, probably representing a hallmark of diffuse Lewy bodies deposition in the brainstem. However, clinical relevance remains uncertain. Given these findings, an add-on therapy with serotonergic agents seems questionable in PD patients, or should be individually tailored, unless severe depression is present.

  5. Kajian implementasi radio siaran digital di Indonesia [Study of digital radio broadcasting implementation in Indonesia

    Directory of Open Access Journals (Sweden)

    Amry Daulat Gultom

    2015-12-01

    Full Text Available Peraturan Menteri Komunikasi dan Informatika RI nomor 21 tahun 2009 tentang  Standar Penyiaran Digital Untuk Penyiaran Radio pada Pita VHF di Indonesia menyatakan bahwa dalam rangka mengatasi permasalahan penggunaan frekuensi VHF Band II untuk penyiaran radio FM yang tidak sesuai dengan rencana induk, serta tidak terpenuhinya permohonan untuk penggunaan kanal frekuensi dari masyarakat, maka perlu dicarikan saluran siaran alternatif dengan menggunakan sistem penyiaran radio digital standard DAB Family. Hingga saat ini belum ada perkembangan berarti terkait implementasinya, sehingga perlu dilakukan penelitian untuk mengetahui potensi radio siaran digital, kesiapan dari sisi pemerintah, operator, dan masyarakat, dan kendala yang dihadapi serta merumuskan strategi yang akan digunakan mengatasinya. Metode analisis yang digunakan adalah SWOT dan TOWS kualitatif dari data wawancara dan studi literatur. Hasil penelitian menunjukkan bahwa pihak stasiun radio sudah siap terhadap digitalisasi radio siaran, pihak pemerintah belum begitu siap karena belum adanya regulasi pendukung Permen Kominfo tentang standard radio digital, dan masyarakat juga belum siap karena kurangnya sosialisasi dan masih susah didapatkannya perangkat penerima siaran radio digital. Pengintegrasian penerima siaran radio digital pada kendaraan bermotor roda empat dan telepon genggam yang baru dapat meningkatkan keberadaan perangkat penerima siaran radio digital.*****The Minister of Communication and Information Regulation number 21 of 2009 on Digital Broadcasting Standards for VHF Band Radio Broadcasting in Indonesia stated that in order to overcome the problems of VHF Band II frequency utilization for FM radio broadcasting that is not in accordance with the master plan, as well as non-fulfillment of the request for frequency channels utilization of the society, neeed to find alternative broadcast channel by DAB Family digital radio broadcasting system. Until now there has no

  6. Radio and Optical Spectra of Objects from Two Complete Samples of Radio Sources

    OpenAIRE

    Chavushyan, V.; Mujica, R.; Gorshkov, A. G.; Konnikova, V. K.; Mingaliev, M.G.; Valdez, J. R.

    2003-01-01

    We present optical identifications and radio spectra for ten radio sources from two flux-density-complete samples. Radio variability characteristics are presented for four objects. The observations were obtained on the RATAN-600 radio telescope at 0.97-21.7 GHz and the 2.1 m telescope of the Haro Observatory in Cananea, Mexico at 4200-9000 =C5. Among the ten objects studied, three are quasars, four are BL Lac objects, two are radio galaxies, and one is a Sy 1 galaxy. Two of the sources identi...

  7. Radio Astronomy in the Undergraduate Curriculum

    Science.gov (United States)

    Payne, J. E.; Brown, J. L.; Walter, D. K.

    2003-12-01

    We summarize the results of a three year program to incorporate radio astronomy into undergraduate research and coursework at South Carolina State University (SCSU). A series of small and inexpensive radio telescopes have been constructed by faculty members with undergraduate student assistance. The telescopes range from a Radio Jove dipole antenna, to a dual frequency alt-az mount solar antenna to a 4.6 meter commercially-built radio telescope operated at 1.42 GHz. SCSU students and faculty have access to larger radio telescopes through a partnership with the Pisgah Astronomical Research Institute (PARI) near Rosman, North Carolina. Projects to date include three years of monitoring solar activity, participation in coordinated observing sessions of Jovian radio bursts and mapping the distribution of galactic neutral hydrogen. Future work will include combined optical and radio observations of stellar radio sources such as RS CVn stars and Algol-type binaries. Support for this work has been provided to SCSU through NASA's PAIR program under NCC 5-454.

  8. Need a Classroom Stimulus? Introduce Radio Astronomy

    Science.gov (United States)

    Derman, Samuel

    2010-01-01

    Silently, invisibly, ceaselessly, our planet Earth is showered by radio waves from every direction and from every region of space. This radio energy originates in our solar system, throughout the Milky Way galaxy, and far beyond, out to the remotest reaches of the universe. Detecting and unraveling the origins of these invisible signals is what…

  9. SUBARCSEC OPTICAL AND RADIO OBSERVATIONS OF THE ...

    African Journals Online (AJOL)

    2005-10-08

    Oct 8, 2005 ... MHz are presented. The radio image at L~band andB, V, R and 1 band images with a. 0.6 arcsec seeing resolve the components. These observations show that the brightness ratio of the components at optical bands is similar to those at radio hands. This strengthens the case for a gravitational lens ...

  10. Superluminal motion in compact radio sources

    Science.gov (United States)

    Marscher, A. P.; Scott, J. S.

    1980-01-01

    The observations of radio sources whose components appear to move superluminally are now sufficient to eliminate certain theoretical models. However, a number of models might be still relevant. The models which involve relativistic bulk motions of the radio components seem to provide the most likely explanation of apparent superluminal motion. A summary of observational predictions of various models for superluminal motions is included.

  11. Radio Afterglows of Gamma Ray Bursts

    Indian Academy of Sciences (India)

    Even though radio band is the least explored of the afterglow spectrum, it has played an important role in the progress of GRB physics, specifically in confirming the hypothesized relativistic effects. Currently radio astronomy is in the beginning of a revolution. The high sensitive Square Kilometer Array (SKA) is being planned ...

  12. Cosmological measurements with forthcoming radio continuum surveys

    CSIR Research Space (South Africa)

    Raccanelli, A

    2012-08-01

    Full Text Available We present forecasts for constraints on cosmological models that can be obtained using the forthcoming radio continuum surveys: the wide surveys with the Low Frequency Array (LOFAR) for radio astronomy, theAustralian SquareKilometreArray Pathfinder...

  13. Nonthermal processing by radio frequency electric fields

    Science.gov (United States)

    Radio frequency electric fields (RFEF) processing is relatively new and has been shown to inactivate bacteria in apple juice, orange juice and apple cider at moderately low temperatures. Key equipment components of the process include a radio frequency power supply and a treatment chamber that is ca...

  14. Orbiting low frequency array for radio astronomy

    NARCIS (Netherlands)

    Rajan, Rai Thilak; Rajan, Raj; Engelen, Steven; Bentum, Marinus Jan; Verhoeven, Chris

    2011-01-01

    Recently new and interesting science drivers have emerged for very low frequency radio astronomy from 0.3 MHz to 30 MHz. However Earth bound radio observations at these wavelengths are severely hampered by ionospheric distortions, man made interference, solar flares and even complete reflection

  15. Reconfigurable Radio-Over-Fiber Networks [Invited

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    2015-01-01

    This paper discusses reconfigurable Radio-over-Fiber networks, including activities in coherent remote access units, silicon photonics for microwave photonics and optical switching.......This paper discusses reconfigurable Radio-over-Fiber networks, including activities in coherent remote access units, silicon photonics for microwave photonics and optical switching....

  16. Adaptive OFDM System Design For Cognitive Radio

    NARCIS (Netherlands)

    Zhang, Q.; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2006-01-01

    Recently, Cognitive Radio has been proposed as a promising technology to improve spectrum utilization. A highly flexible OFDM system is considered to be a good candidate for the Cognitive Radio baseband processing where individual carriers can be switched off for frequencies occupied by a licensed

  17. Spectral Variability in Radio-Loud Quasars

    Indian Academy of Sciences (India)

    The spectral variability of a sample of 44 Flat-Spectrum Radio Quasars (FSRQs) and 18 Steep-Spectrum Radio Quasars (SSRQs) in SDSS stripe 82 region is investigated. Twenty-five of 44 FSRQs show a bluer-when-brighter trend (BWB), while only one FSRQ shows a redder-when-brighter trend, which is in contrast to our ...

  18. Radio Listening, Television Viewing and Comprehension ...

    African Journals Online (AJOL)

    Reading comprehension is the basic foundation for functional literacy and scholastic achievement. However, most school children spend a great deal of their time watching television or listening to radio than in reading. The research effort was thus; set out to investigate the effects of television and radio programmes to the ...

  19. 47 CFR 32.2231 - Radio systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Radio systems. 32.2231 Section 32.2231 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2231 Radio systems. (a...

  20. Reconfigurable Radio-Over-Fiber Networks

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

    2015-01-01

    This paper discusses reconfigurable Radio-over-Fiber networks, including activities in coherent remote access units, silicon photonics for microwave photonics and optical switching.......This paper discusses reconfigurable Radio-over-Fiber networks, including activities in coherent remote access units, silicon photonics for microwave photonics and optical switching....

  1. Teacher's perception of current radio literacy programme's ...

    African Journals Online (AJOL)

    In spite of the numerous literacy programmes aired through the radio, Nigeria is still ranked among the ten nations of the world that experience high illiteracy rate. This research was to find out teachers' perception of the effectiveness of the current radio literacy programme including the development of the basic language ...

  2. A review on radio based activity recognition

    Directory of Open Access Journals (Sweden)

    Shuangquan Wang

    2015-02-01

    Full Text Available Recognizing human activities in their daily living enables the development and widely usage of human-centric applications, such as health monitoring, assisted living, etc. Traditional activity recognition methods often rely on physical sensors (camera, accelerometer, gyroscope, etc. to continuously collect sensor readings, and utilize pattern recognition algorithms to identify user׳s activities at an aggregator. Though traditional activity recognition methods have been demonstrated to be effective in previous work, they raise some concerns such as privacy, energy consumption and deployment cost. In recent years, a new activity recognition approach, which takes advantage of body attenuation and/or channel fading of wireless radio, has been proposed. Compared with traditional activity recognition methods, radio based methods utilize wireless transceivers in environments as infrastructure, exploit radio communication characters to achieve high recognition accuracy, reduce energy cost and preserve user׳s privacy. In this paper, we divide radio based methods into four categories: ZigBee radio based activity recognition, WiFi radio based activity recognition, RFID radio based activity recognition, and other radio based activity recognition. Some existing work in each category is introduced and reviewed in detail. Then, we compare some representative methods to show their advantages and disadvantages. At last, we point out some future research directions of this new research topic.

  3. Interactive radio: distance education in the classroom.

    Science.gov (United States)

    1988-01-01

    The Honduran Association for Socioeconomic Growth and Development (AVANCE) in conjunction with the U.S. Agency for International Development's Radio Learning Project has developed and promoted programs for radio that encourage interactive learning in Latin America. The Second Interamerican Conference on Interactive Radio was recently held in Tela, Honduras where educators and participants came to attend workshops on scriptwriting, instructional design, community support and other related topics. The participants had the opportunity to study the second generation of interactive radio. Beginning in 1973, Nicaragua began an interactive radio program written for early grade mathematics students. Currently, Honduras is marketing a mathematics program entitled, La Familia de los Numeros," or the Family of Numbers to other countries. In Bolivia, an organization called, "Fe y Alegria," or Faith and Happiness is broadcasting educational programs through the use of interactive radio. In Ecuador, testing has begun to study the viability of interactive radio for their educational system, and in Costa Rica, replication of Honduras' "Familia de los Numeros" has begun. Teachers have noted an improved grasp of subject matter and better attentiveness through the use of interactive radio programs. The programs present 30 minutes of mathematics information and 30 minutes of language information. For each grade, 170 programs have been developed.

  4. A Radio-Controlled Car Challenge

    Science.gov (United States)

    Roman, Harry T.

    2010-01-01

    Watching a radio-controlled car zip along a sidewalk or street has become a common sight. Within this toy are the basic ingredients of a mobile robot, used by industry for a variety of important and potentially dangerous tasks. In this challenge, students consider modifying an of-the-shelf, radio-controlled car, adapting it for a robotic task.

  5. The Fascinating World of Radio Communications.

    Science.gov (United States)

    Green, Wayne, Ed.

    Intended mainly for the amateur radio operator, or "ham," this book outlines some of the pleasures to be had in amateur radio, including DXing (calling distant stations) and helping in emergencies. The steps in starting out on this hobby, including getting Citizens' Band (CB) gear, a CB license, and a receiver and antenna, are described.…

  6. Ionosphere and its Influence on Radio Communications

    Indian Academy of Sciences (India)

    Communications. R S Dabas is at the Radio. Science Division of. National Physical. Laboratory, New Delhi and is responsible for characterization of ionospheric media for radio communication applications. His main area of research is the study of equatorial and low latitude ionosphere. i.e. its properties and dynamics.

  7. Antenna Construction and Propagation of Radio Waves.

    Science.gov (United States)

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on antenna construction and propagation of radio waves is designed to provide communicators with instructions in the selection and/or construction of the proper antenna(s) for use with current field radio equipment. Introductory materials include…

  8. The Giant Radio Array for Neutrino Detection

    DEFF Research Database (Denmark)

    Martineau-Huynh, Olivier; Bustamante, Mauricio; Carvalho, Washington

    2017-01-01

    The Giant Radio Array for Neutrino Detection (GRAND) is a planned array of ~200 000 radio antennas deployed over ~200 000 km2 in a mountainous site. It aims primarly at detecting high-energy neutrinos via the observation of extensive air showers induced by the decay in the atmosphere of taus...

  9. Towards Cognitive Radio for emergency networks

    NARCIS (Netherlands)

    Zhang, Q.; Hoeksema, F.W.; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2006-01-01

    Large parts of the assigned spectrum is underutilized while the increasing number of wireless multimedia applications leads to spectrum scarcity. Cognitive Radio is an option to utilize non-used parts of the spectrum that actually are assigned to primary services. The benefits of Cognitive Radio are

  10. Radio monitoring problems, methods, and equipment

    CERN Document Server

    Rembovsky, Anatoly; Kozmin, Vladimir; Smolskiy, Sergey

    2009-01-01

    Offers a unified approach to fundamental aspects of Automated Radio Monitoring (ARM). This book discusses the development, modeling, design, and manufacture of ARM systems. It provides classification and descriptions of modern high-efficient hardware-software ARM equipment, including the equipment for detection and radio direction-finding.

  11. 76 FR 67375 - Radio Broadcasting Services; Various Locations

    Science.gov (United States)

    2011-11-01

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Various Locations AGENCY: Federal Communications..., Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio Division... the new application procedures for radio stations to change their communities of license. However...

  12. VHF spectrum monitoring using Meraka cognitive radio platform

    CSIR Research Space (South Africa)

    Aderonmu, AI

    2012-11-01

    Full Text Available discuss the Meraka Cognitive Radio Platform (MCRP) developed using the second version of the Universal Serial Radio Peripheral (USRP2) hardware and the GNU Radio software. We also discussed how the spectrum monitoring system is being implemented...

  13. Novel Observational Technique of Gravitational Wave (GW) Events: Detecting and Locating Electromagnetic Counterparts to GW Sources using Dust Scattering Halos

    Science.gov (United States)

    Nederlander, Richard; Paerels, Frits

    2018-01-01

    We discuss a novel observational technique for detecting and locating the electromagnetic counterpart to its GW source, providing astronomers with a several-hour reprieve after a GW event’s occurrence. The technique relies on identifying a dust scattering halo caused by GW-produced X-rays scattering off Galactic dust clouds. The travel time delay of these scattered photons makes them detectable for up to several hours after the prompt event, and the location of the gravitational wave source will be at the geometric center of the halo. The center can be determined with precision sufficient enough to allow the host galaxy to be discerned. This novel technique will be especially relevant for binary black-hole mergers because their counterparts have, as of now, been difficult to detect.

  14. Effect of counterpart metals in carbon-supported Pt-based catalysts prepared using radiation chemical method

    Science.gov (United States)

    Okazaki, Tomohisa; Seino, Satoshi; Matsuura, Yoshiyuki; Otake, Hiroaki; Kugai, Junichiro; Ohkubo, Yuji; Nitani, Hiroaki; Nakagawa, Takashi; Yamamoto, Takao A.

    2017-04-01

    The process of nanoparticle formation by radiation chemical synthesis in a heterogeneous system has been investigated. Carbon-supported Pt-based bimetallic nanoparticles were synthesized using a high-energy electron beam. Rh, Cu, Ru, and Sn were used as counterpart metals. The nanoparticles were characterized by inductively coupled plasma atomic emission spectrometry, transmission electron microscopy, X-ray diffraction, and X-ray absorption spectroscopy. PtRh formed a uniform random alloy nanoparticle, while Cu partially formed an alloy with Pt and the remaining Cu existed as CuO. PtRu formed an alloy structure with a composition distribution of a Pt-rich core and Ru-rich shell. No alloying was observed in PtSn, which had a Pt-SnO2 structure. The alloy and oxide formation mechanisms are discussed considering the redox potentials, the standard enthalpy of oxide formation, and the solid solubilities of Pt and the counterpart metals.

  15. Gamma-ray Burst and Gravitational Wave Counterpart Prospects in the MeV Band with AMEGO

    Science.gov (United States)

    Racusin, Judith; AMEGO Team

    2018-01-01

    The All-sky Medium Energy Gamma-ray Observatory (AMEGO) Probe mission concept is uniquely suited to address open questions in Gamma-ray Burst (GRB) science including the search for counterparts to gravitational-wave events. AMEGO is a wide field of view instrument (~60 deg radius) with a broad energy range (~200 keV to >10 GeV) and excellent continuum sensitivity. The sensitivity improvement will allow for probes of GRB emission mechanisms and jet composition in ways that have not been accessible with previous instruments. Potential for polarization measurement may also have profound impacts on the understanding of GRB mechanisms. AMEGO will also be an excellent facility for the search for gravitational wave counterparts to binary mergers including at least one neutron star, which are thought to produce short duration GRBs. This poster will describe how the AMEGO will advance these fields.

  16. Gamma-ray Burst and Gravitational Wave Counterpart Prospects in the MeV Band with AMEGO

    Science.gov (United States)

    Racusin, Judith L.

    2017-08-01

    The All-sky Medium Energy Gamma-ray Observatory (AMEGO) Probe mission concept is uniquely suited to address open questions in Gamma-ray Burst (GRB) science including the search for counterparts to gravitational-wave events. AMEGO is a wide field of view instrument (~60 deg radius) with a broad energy range (~200 keV to >10 GeV) and excellent continuum sensitivity. The sensitivity improvement will allow for probes of GRB emission mechanisms and jet composition in ways that have not been accessible with previous instruments. Potential for polarization measurement may also have profound impacts on the understanding of GRB mechanisms. AMEGO will also be an excellent facility for the search for gravitational wave counterparts to binary mergers including at least one neutron star, which are thought to produce short duration GRBs. This poster will describe how the AMEGO will advance these fields.

  17. Software defined radio based multi-carrier multi-function waveform for cognitive radio

    Science.gov (United States)

    Zhou, Ruolin; Li, Xue; Chakravarthy, Vasu; Wu, Zhiqiang

    2010-04-01

    In this paper, we demonstrate an adaptive multicarrier multi-function waveform generator for cognitive radio via software defined radio. Using a USRP (universal software radio peripheral) software defined radio boards and GNU radio software, we implement a multi-carrier waveform generator which can generate multi-function waveforms such as OFDM, NC-OFDM, MC-CDMA, NC-MC-CDMA, CI/MC-CDMA, NCCI/ MC-CDMA, TDCS for cognitive radio. Additionally, we demonstrate a portable overlay cognitive radio using this multicarrier multi-function waveform generator. This cognitive radio is capable of detecting primary users in real time and adaptively adjusting its transmission parameters to avoid interference to primary users. More importantly, this cognitive radio can take advantage of multiple spectrum holes by employing non-contiguous multi-carrier transmission technologies. Additionally, we demonstrate that when the primary user transmission changes, the cognitive radio dynamically adjusts its transmission accordingly. We also demonstrate seamless real time video transmission between two cognitive radio nodes, while avoiding interference from primary users and interference to primary users operating in the same spectrum.

  18. Imaging spectroscopy of type U and J solar radio bursts with LOFAR

    Science.gov (United States)

    Reid, Hamish A. S.; Kontar, Eduard P.

    2017-10-01

    Context. Radio U-bursts and J-bursts are signatures of electron beams propagating along magnetic loops confined to the corona. The more commonly observed type III radio bursts are signatures of electron beams propagating along magnetic loops that extend into interplanetary space. Given the prevalence of solar magnetic flux to be closed in the corona, why type III bursts are more frequently observed than U-bursts or J-bursts is an outstanding question. Aims: We use Low-Frequency Array (LOFAR) imaging spectroscopy between 30-80 MHz of low-frequency U-bursts and J-bursts, for the first time, to understand why electron beams travelling along coronal loops produce radio emission less often. Radio burst observations provide information not only about the exciting electron beams but also about the structure of large coronal loops with densities that are too low for standard extreme ultraviolet (EUV) or X-ray analysis. Methods: We analysed LOFAR images of a sequence of two J-bursts and one U-burst. The different radio source positions were used to model the spatial structure of the guiding magnetic flux tube and then deduce the energy range of the exciting electron beams without the assumption of a standard density model. We also estimated the electron density along the magnetic flux rope and compared it to coronal models. Results: The radio sources infer a magnetic loop that is 1 solar radius in altitude with the highest frequency sources starting around 0.6 solar radii. Electron velocities were found between 0.13 c and 0.24 c with the front of the electron beam travelling faster than the back of the electron beam. The velocities correspond to energy ranges within the beam from 0.7-11 keV to 0.7-43 keV. The density along the loop is higher than typical coronal density models and the density gradient is smaller. Conclusions: We found that a more restrictive range of accelerated beam and background plasma parameters can result in U-bursts or J-bursts, causing type III

  19. Cognitive Radio RF: Overview and Challenges

    Directory of Open Access Journals (Sweden)

    Van Tam Nguyen

    2012-01-01

    Full Text Available Cognitive radio system (CRS is a radio system which is aware of its operational and geographical environment, established policies, and its internal state. It is able to dynamically and autonomously adapt its operational parameters and protocols and to learn from its previous experience. Based on software-defined radio (SDR, CRS provides additional flexibility and offers improved efficiency to overall spectrum use. CRS is a disruptive technology targeting very high spectral efficiency. This paper presents an overview and challenges of CRS with focus on radio frequency (RF section. We summarize the status of the related regulation and standardization activities which are very important for the success of any emerging technology. We point out some key research challenges, especially implementation challenges of cognitive radio (CR. A particular focus is on RF front-end, transceiver, and analog-to-digital and digital-to-analog interfaces which are still a key bottleneck in CRS development.

  20. Radio wavelength transients: Current and emerging prospects

    Science.gov (United States)

    Lazio, J.

    2008-03-01

    Known classes of radio wavelength transients range from the nearby stellar flares and radio pulsars to the distant Universe γ-ray burst afterglows. Hypothesized classes of radio transients include analogs of known objects, e.g., extrasolar planets emitting Jovian-like radio bursts and giant-pulse emitting pulsars in other galaxies, to the exotic, prompt emission from γ-ray bursts, evaporating black holes, and transmitters from other civilizations. A number of instruments and facilities are either under construction or in early observational stages and are slated to become available in the next few years. With a combination of wide fields of view and wavelength agility, the detection and study of radio transients will improve immensely.

  1. The crisis of the radio producing

    Directory of Open Access Journals (Sweden)

    Dr. Raúl Garcés

    2007-09-01

    Full Text Available In a media world highly influenced by new technologies revolution and the increasing impact of television, speeches on radio are frequently polarized: in one side, some scholars argue radio belongs to the past and it is no longer able of attracting younger audiences. In the other, lay those who predict long life to radio as a source of alternative and communitarian communication experiences. The author reviews the arguments that sustain both perspectives and emphasizes the need of renovating radio producing with audacious and creative formulas. At the same time, he discusses some of the challenges Cuban radio has ahead to attract new audiences, when television and printed press are recovering from the economic crack the Island suffered after Eastern European socialism disappeared.

  2. Hybrid cognitive engine for radio systems adaptation

    KAUST Repository

    Alqerm, Ismail

    2017-07-20

    Network efficiency and proper utilization of its resources are essential requirements to operate wireless networks in an optimal fashion. Cognitive radio aims to fulfill these requirements by exploiting artificial intelligence techniques to create an entity called cognitive engine. Cognitive engine exploits awareness about the surrounding radio environment to optimize the use of radio resources and adapt relevant transmission parameters. In this paper, we propose a hybrid cognitive engine that employs Case Based Reasoning (CBR) and Decision Trees (DTs) to perform radio adaptation in multi-carriers wireless networks. The engine complexity is reduced by employing DTs to improve the indexing methodology used in CBR cases retrieval. The performance of our hybrid engine is validated using software defined radios implementation and simulation in multi-carrier environment. The system throughput, signal to noise and interference ratio, and packet error rate are obtained and compared with other schemes in different scenarios.

  3. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    DEFF Research Database (Denmark)

    Aatrokoski, J.; Lähteenmäki, A.; Lavonen, N.

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz......, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase...... of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data...

  4. VLT observations of the magnetar CXO J164710.2-455216 and the detection of a candidate infrared counterpart

    Science.gov (United States)

    Testa, V.; Mignani, R. P.; Hummel, W.; Rea, N.; Israel, G. L.

    2018-01-01

    We present deep observations of the field of the magnetar CXO J164710.2-455216 in the star cluster Westerlund 1, obtained in the near-infrared with the adaptive optics camera NACO@VLT. We detected a possible candidate counterpart at the Chandra position of the magnetar, of magnitudes J = 23.5 ± 0.2, H = 21.0 ± 0.1 and KS = 20.4 ± 0.1. The KS-band measurements available for two epochs (2006 and 2013) do not show significant signs of variability but only a marginal indication that the flux varied (at the 2σ level), consistent with the fact that the observations were taken when CXO J164710.2-455216 was in quiescence. At the same time, we also present colour-magnitude and colour-colour diagrams in the J, H and KS bands from the 2006 epoch only, the only one with observations in all three bands, showing that the candidate counterpart lies in the main bulk of objects describing a relatively well-defined sequence. Therefore, based on its colours and lack of variability, we cannot yet associate the candidate counterpart to CXO J164710.2-455216. Future near-infrared observations of the field, following up a source outburst, would be crucial to confirm the association with the detection of near-infrared variability and colour evolution.

  5. Search of MeV-GeV counterparts of TeV sources with AGILE in pointing mode

    Science.gov (United States)

    Rappoldi, A.; Lucarelli, F.; Pittori, C.; Longo, F.; Cattaneo, P. W.; Verrecchia, F.; Tavani, M.; Bulgarelli, A.; Chen, A. W.; Colafrancesco, S.; Donnarumma, I.; Giuliani, A.; Morselli, A.; Sabatini, S.; Vercellone, S.

    2016-03-01

    Context. Known TeV sources detected by major Čerenkov telescopes are investigated to identify possible MeV-GeV γ-ray counterparts. Aims: A systematic study of the known sources in the web-based TeVCat catalog has been performed to search for possible γ-ray counterparts on the AGILE data collected during the first period of operations in observing pointing mode. Methods: For each TeV source, a search for a possible γ-ray counterpart that is based on a multi-source maximum likelihood algorithm is performed on the AGILE data taken with the GRID instrument from July 2007 to October 2009. Results: In the case of high-significance detection, the average γ-ray flux is estimated. For cases of low-significance detection the 95% confidence level (CL) flux upper limit is given. 52 TeV sources out of 152 (corresponding to ~34% of the analysed sample) show a significant excess in the AGILE data covering the pointing observation period. Conclusions: This analysis found 26 new AGILE sources with respect to the AGILE reference catalogs, 15 of which are galactic, 7 are extragalactic and 4 are unidentified. Detailed tables with all available information on the analysed sources are presented. An interactive online version of the considered source list including all the analysis results is also available at the website http://www.asdc.asi.it/agiletevcat/

  6. Health and functional status and utilization of health care services among holocaust survivors and their counterparts in Israel.

    Science.gov (United States)

    Iecovich, Esther; Carmel, Sara

    2010-01-01

    To examine differences in health and functional status and in utilization of health services between holocaust survivors and their counterparts; and (b) to investigate if holocaust survivor status is a significant predictor of health status, functional status, and utilization of health services. The study included 1255 respondents of whom 272 were holocaust survivors. Interviews were conducted face-to-face at the respondents' homes. Participants were asked about their health (self-rated health and comorbidity) and functional (ADL and IADL) status, utilization of inpatient and outpatient health care services, age, gender, education, marital status, length of residence in Israel, and if they were holocaust survivors. Holocaust survivors, who were frailer and more chronically ill compared to their counterparts, visited their family physician and the nurse at the health care clinic more often than their counterparts did, and received more homecare services. Yet, there were no differences between them in the utilization of other health care services such as visits to specialists, emergency department, and hospitalizations. Holocaust survivors are more homebound due to more morbidity and functional limitations and therefore receive more health home care services that offset the utilization of other health services. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  7. Calculus III essentials

    CERN Document Server

    REA, Editors of

    2012-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Calculus III includes vector analysis, real valued functions, partial differentiation, multiple integrations, vector fields, and infinite series.

  8. Radio language teaching in Kenyan sch

    Directory of Open Access Journals (Sweden)

    Maurice Imhoof

    2013-02-01

    Full Text Available The Radio Language Arts Project in Kenya is currently testing the feasibility of using radio intensively to serve as the major medium of English instruction in the formal classroom setting. The project, now in its third and final year of lesson development and experimentation, is evaluating the effectiveness of radio in teaching English to children in the first three primary grades. The thirty-minute, daily broacasts are part of the normal school curriculum. Preliminary results show substantial achievement gains by the radio students and strong support from school personnel. The project demonstrates that carefully designed, written, and produced radio lessons, aided by human interaction fostered by a teacher or other guide, can be an effective alternative to more complex and more costly techniques. In Kenia word die uitvoerbaarheid daarvan om die radio intensief te gebruik as die belangrikste medium by die onderrig van Engels in die formele klassituasie, getoets deur projek "Radio Language Arts". Die projek, wat tans in sy derde en finale jaar van lesontwikkeling en eksperimentasie verkeer, evalueer die doeltreffendheid van die radio in Engels-onderrig aan kinders in die eerste drie jaar van die primere skool. Die halfuur lange, daaglikse uitsendings vorm deel van die norm ale kurrikulum. Voorlopige resultate vertoon aansienlike winste in die prestasies van radio-leerlinge en 'n sterk aanhang deur personeel. Die projek demonstreer dat noukeurig ontwerpte, geskrewe en uitgevoerde radio-lesse, ondersteun deur menslike interaksie in die vorm van 'n onderwyser of gids, 'n doeltreffende alternatief kan wees vir meer ingewikkelde en duur metodes.

  9. VLBI Astrometry of 22 Southern Hemisphere Radio Sources

    Science.gov (United States)

    Fey, Alan L.; Ojha, Roopesh; Jauncey, David L.; Johnston, Kenneth J.; Reynolds, John E.; Lovell, James E. J.; Tzioumis, Anastasios K.; Quick, Jonathan F. H.; Nicolson, George D.; Ellingsen, Simon P.; McCulloch, Peter M.; Koyama, Yasuhiro

    2004-06-01

    Milliarcsecond accurate radio positions for 22 Southern Hemisphere extragalactic sources are reported. These positions are derived from Mark III Very Long Baseline Interferometry observations made between 2003 February and 2003 August. The results presented here supplement an ongoing project to increase the sky density of Souther Hemisphere sources in order to better define the International Celestial Reference Frame and to provide additional phase reference sources with accurate positions for use in astrophysical observations. The positions for all 22 sources are south of declination = -30 degrees (positions for ten of the sources are south of declination = -60 degrees) and represent the largest group of new milliarcsecond accurate astrometric positions for sources in this declination range since the initial definition of the ICRF. The reported positions have average formal uncertainties of 0.5 milliarcseconds in right ascension and 0.6 milliarcseconds in declination.

  10. Accurate Astrometry of 22 Southern Hemisphere Radio Sources

    Science.gov (United States)

    Fey, Alan L.; Ojha, Roopesh; Jauncey, David L.; Johnston, Kenneth J.; Reynolds, John E.; Lovell, James E. J.; Tzioumis, Anastasios K.; Quick, Jonathan F. H.; Nicolson, George D.; Ellingsen, Simon P.; McCulloch, Peter M.; Koyama, Yasuhiro

    2004-03-01

    Milliarcsecond-accurate radio positions for 22 southern hemisphere extragalactic sources are reported. These positions are derived from Mark III very long baseline interferometry observations made between 2003 February and 2003 August. The results presented here supplement an ongoing project to increase the sky density of southern hemisphere sources in order to better define the International Celestial Reference Frame and to provide additional phase-reference sources with accurate positions for use in astrophysical observations. The positions for all 22 sources are south of δ=-30° (positions for 10 of the sources are south of δ=-60°) and represent the largest group of new milliarcsecond-accurate astrometric positions for sources in this declination range since the initial definition of the International Celestial Reference Frame. The reported positions have average formal uncertainties of 0.5 mas in right ascension and 0.6 mas in declination.

  11. Can Radio Telescopes Find Axions?

    Science.gov (United States)

    Kohler, Susanna

    2017-08-01

    axions. Now scientists Katharine Kelley and Peter Quinn at ICRAR, University of Western Australia, have explored how we might use next-generation radio telescopes to search for photons that were created by axions interacting with the magnetic fields of our galaxy.Hope for Next-Gen TelescopesPotential axion coupling strengths vs. mass (click for a closer look). The axion mass is thought to lie between a eV and a meV; two theoretical models are shown with dashed lines. The plot shows the sensitivity of the upcoming SKA and its precursors, ASKAP and MEERKAT. [KelleyQuinn 2017]By using a simple galactic halo model and reasonable assumptions for the central galactic magnetic field even taking into account the time dependence of the field Kelley and Quinn estimate the radio-frequency power density that we would observe at Earth from axions being converted to photons within the Milky Ways magnetic field.The authors then compare this signature to the detection capabilities of upcoming radio telescope arrays. They show that the upcoming Square Kilometer Array and its precursors should have the capability to detect signs of axions across large parts of parameter space.Kelley and Quinn conclude that theres good cause for optimism about future radio telescopes ability to detect axions. And if we did succeed in making a detection, it would be a triumph for both particle physics and astrophysics, finally providing an explanation for the universes dark matter.CitationKatharine Kelley and P. J. Quinn 2017 ApJL 845 L4. doi:10.3847/2041-8213/aa808d

  12. Radio Propagation into Modern Buildings

    DEFF Research Database (Denmark)

    Rodriguez Larrad, Ignacio; Nguyen, Huan Cong; Jørgensen, Niels T.K.

    2014-01-01

    constructions. These materials are used in favor of achieving a proper level of thermal isolation, but it has been noticed that they can impact heavily on radio signal propagation. This paper presents a measurement-based analysis of the outdoor-to-indoor attenuation experienced in several modern constructions...... compared to an old building. The measurements are performed for frequencies from 800 MHz to 18 GHz with the aim of identifying the frequency dependence and the impact of the new materials on not only the cellular frequency bands used today (mainly below 3 GHz), but also the potential future bands (above 3...... GHz). The results show a material dependent and a frequency dependent attenuation, with an average increase of 20-25 dB in modern constructions compared to the old construction, which presents a low and almost constant attenuation below 10 dB. The different measurement results and observations...

  13. Direct Broadcast Satellite: Radio Program

    Science.gov (United States)

    Hollansworth, James E.

    1992-01-01

    NASA is committed to providing technology development that leads to the introduction of new commercial applications for communications satellites. The Direct Broadcast Satellite-Radio (DBS-R) Program is a joint effort between The National Aeronautics and Space Administration (NASA) and The United States Information Agency/Voice of America (USIA/VOA) directed at this objective. The purpose of this program is to define the service and develop the technology for a direct-to-listener satellite sound broadcasting system. The DBS-R Program, as structured by NASA and VOA, is now a three-phase program designed to help the U.S. commercial communications satellite and receiver industry bring about this new communications service. Major efforts are being directed towards frequency planning hardware and service development, service demonstration, and experimentation with new satellite and receiver technology.

  14. Radio Frequency Energy Harvesting Sources

    Directory of Open Access Journals (Sweden)

    Action NECHIBVUTE

    2017-12-01

    Full Text Available This radio frequency (RF energy harvesting is an emerging technology and research area that promises to produce energy to run low-power wireless devices. The great interest that has recently been paid to RF harvesting is predominantly driven by the great progress in both wireless communication systems and broadcasting technologies that have availed a lot of freely propagating ambient RF energy. The principle aim of an RF energy harvesting system is to convert the received ambient RF energy into usable DC power. This paper presents a state of the art concise review of RF energy harvesting sources for low power applications, and also discusses open research questions and future research directions on ambient RF energy harvesting.

  15. Ecuador: Prensa, radio y tv

    Directory of Open Access Journals (Sweden)

    Zuly Meneses

    2015-01-01

    Full Text Available CIESPAL, realizó una investigación "Inventario de Medios de comunicación en América Latina", se refirió a 314 medios existentes en el país. El artículo se basa en la información de esta investigación y trata sobre: la potencia cobertura y redes; la propiedad pública y privada; estaciones televisivas por propiedad y carácter; tendencias de la programación televisiva; tendencias por grupos temáticos. Concluye el estudio en que la gran mayoría de medios de comunicación masiva en el Ecuador son de propiedad privada se localizan en las ciudades más importantes son esencialmente urbanos a excepción de la radio que atiende a sectores campesinos y urbano marginales

  16. VLSI Technology for Cognitive Radio

    Science.gov (United States)

    VIJAYALAKSHMI, B.; SIDDAIAH, P.

    2017-08-01

    One of the most challenging tasks of cognitive radio is the efficiency in the spectrum sensing scheme to overcome the spectrum scarcity problem. The popular and widely used spectrum sensing technique is the energy detection scheme as it is very simple and doesn’t require any previous information related to the signal. We propose one such approach which is an optimised spectrum sensing scheme with reduced filter structure. The optimisation is done in terms of area and power performance of the spectrum. The simulations of the VLSI structure of the optimised flexible spectrum is done using verilog coding by using the XILINX ISE software. Our method produces performance with 13% reduction in area and 66% reduction in power consumption in comparison to the flexible spectrum sensing scheme. All the results are tabulated and comparisons are made. A new scheme for optimised and effective spectrum sensing opens up with our model.

  17. A NEW PERSPECTIVE OF THE RADIO BRIGHT ZONE AT THE GALACTIC CENTER: FEEDBACK FROM NUCLEAR ACTIVITIES

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jun-Hui [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Morris, Mark R. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Goss, W. M., E-mail: jzhao@cfa.harvard.edu [NRAO, P.O. Box O, Socorro, NM 87801 (United States)

    2016-02-01

    New observations of Sgr A have been carried out with the Jansky VLA in the B and C arrays using the broadband (2 GHz) continuum mode at 5.5 GHz. The field of view covers the central 13′ (30 pc) region of the radio-bright zone at the Galactic center. Using the multi-scale and multi-frequency-synthesis (MS-MFS) algorithms in CASA, we have imaged Sgr A with a resolution of 1″, achieving an rms noise of 8 μJy beam{sup −1}, and a dynamic range of 100,000:1. Both previously known and newly identified radio features in this region are revealed, including numerous filamentary sources. The radio continuum image is compared with Chandra X-ray images, with a CN emission-line image obtained with the Submillimeter Array and with detailed Paschen-α images obtained with Hubble Space Telescope/NICMOS. We discuss several prominent features in the radio image. The “Sgr A west Wings” extend 2′ (5 pc) from the NW and SE tips of the Sgr A west H ii region (the “Mini-spiral”) to positions located 2.9 and 2.4 arcmin to the northwest and southeast of Sgr A*, respectively. The NW wing, along with several other prominent features, including the previously identified “NW Streamers,” form an elongated radio lobe (NW lobe), oriented nearly perpendicular to the Galactic plane. This radio lobe, with a size of 6.′3 × 3.′2 (14.4 pc × 7.3 pc), has a known X-ray counterpart. In the outer region of the NW lobe, a row of three thermally emitting rings is observed. A field containing numerous amorphous radio blobs extends for a distance of ∼2 arcmin beyond the tip of the SE wing; these newly recognized features coincide with the SE X-ray lobe. Most of the amorphous radio blobs in the NW and SE lobes have Paschen-α counterparts. We propose that they have been produced by shock interaction of ambient gas concentrations with a collimated nuclear wind or an outflow that originated from within the circumnuclear disk (CND). We also discuss the possibility that the ionized

  18. Radio flares of compact binary mergers: the effect of non-trivial outflow geometry

    Science.gov (United States)

    Margalit, Ben; Piran, Tsvi

    2015-10-01

    The next generation gravitational waves (GW) detectors are most sensitive to GW emitted by compact (neutron star/black hole) binary mergers. If one of those is a neutron star the merger will also emit electromagnetic radiation via three possible channels: gamma-ray bursts and their (possibly orphan) afterglows, Li-Paczynski Macronovae and radio flares. This accompanying electromagnetic radiation is vitally important in confirming the GW detections. It could also reveal a wealth of information regarding the merger and will open a window towards multimessenger astronomy. Identifying and characterizing these counterparts is therefore of utmost importance. In this work, we explore late time radio flares emitted by the dynamically ejected outflows. We build upon previous work and consider the effect of the outflow's non-trivial geometry. Using an approximate method, we estimate the radio light-curves for several ejected matter distributions obtained in numerical simulations. Our method provides an upper limit to the effect of non-sphericity. Together with the spherical estimates, the resulting light curves bound the actual signal. We find that while non-spherical geometries can in principle lead to an enhanced emission, in most cases they result in an increase in the time-scale compared with a corresponding spherical configuration. This would weaken somewhat these signals and might decrease the detection prospects.

  19. A MATLAB Library for Rapid Prototyping of Wireless Communications Algorithms with the Universal Software Radio Peripheral (USRP) Radio Family

    Science.gov (United States)

    2013-06-01

    A MATLAB Library for Rapid Prototyping of Wireless Communications Algorithms with the Universal Software Radio Peripheral ( USRP ) Radio Family...Algorithms with the Universal Software Radio Peripheral ( USRP ) Radio Family Gunjan Verma and Paul Yu Computational and Information Sciences...Universal Software Radio Pheriphal ( USRP ) Radio Family 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Gunjan Verma

  20. A novel Porphyromonas gingivalis enzyme: An atypical dipeptidyl peptidase III with an ARM repeat domain.

    Directory of Open Access Journals (Sweden)

    Altijana Hromić-Jahjefendić

    Full Text Available Porphyromonas gingivalis, an asaccharolytic Gram-negative oral anaerobe, is a major pathogen associated with adult periodontitis, a chronic infective disease that a significant percentage of the human population suffers from. It preferentially utilizes dipeptides as its carbon source, suggesting the importance of dipeptidyl peptidase (DPP types of enzyme for its growth. Until now DPP IV, DPP5, 7 and 11 have been extensively investigated. Here, we report the characterization of DPP III using molecular biology, biochemical, biophysical and computational chemistry methods. In addition to the expected evolutionarily conserved regions of all DPP III family members, PgDPP III possesses a C-terminal extension containing an Armadillo (ARM type fold similar to the AlkD family of bacterial DNA glycosylases, implicating it in alkylation repair functions. However, complementation assays in a DNA repair-deficient Escherichia coli strain indicated the absence of alkylation repair function for PgDPP III. Biochemical analyses of recombinant PgDPP III revealed activity similar to that of DPP III from Bacteroides thetaiotaomicron, and in the range between activities of human and yeast counterparts. However, the catalytic efficiency of the separately expressed DPP III domain is ~1000-fold weaker. The structure and dynamics of the ligand-free enzyme and its complex with two different diarginyl arylamide substrates was investigated using small angle X-ray scattering, homology modeling, MD simulations and hydrogen/deuterium exchange (HDX. The correlation between the experimental HDX and MD data improved with simulation time, suggesting that the DPP III domain adopts a semi-closed or closed form in solution, similar to that reported for human DPP III. The obtained results reveal an atypical DPP III with increased structural complexity: its superhelical C-terminal domain contributes to peptidase activity and influences DPP III interdomain dynamics. Overall, this

  1. Grote Reber, Radio Astronomy Pioneer, Dies

    Science.gov (United States)

    2002-12-01

    Grote Reber, one of the earliest pioneers of radio astronomy, died in Tasmania on December 20, just two days shy of his 91st birthday. Reber was the first person to build a radio telescope dedicated to astronomy, opening up a whole new "window" on the Universe that eventually produced such landmark discoveries as quasars, pulsars and the remnant "afterglow" of the Big Bang. His self- financed experiments laid the foundation for today's advanced radio-astronomy facilities. Grote Reber Grote Reber NRAO/AUI photo "Radio astronomy has changed profoundly our understanding of the Universe and has earned the Nobel Prize for several major contributions. All radio astronomers who have followed him owe Grote Reber a deep debt for his pioneering work," said Dr. Fred Lo, director of the National Radio Astronomy Observatory (NRAO). "Reber was the first to systematically study the sky by observing something other than visible light. This gave astronomy a whole new view of the Universe. The continuing importance of new ways of looking at the Universe is emphasized by this year's Nobel Prizes in physics, which recognized scientists who pioneered X-ray and neutrino observations," Lo added. Reber was a radio engineer and avid amateur "ham" radio operator in Wheaton, Illinois, in the 1930s when he read about Karl Jansky's 1932 discovery of natural radio emissions coming from outer space. As an amateur operator, Reber had won awards and communicated with other amateurs around the world, and later wrote that he had concluded "there were no more worlds to conquer" in radio. Learning of Jansky's discovery gave Reber a whole new challenge that he attacked with vigor. Analyzing the problem as an engineer, Reber concluded that what he needed was a parabolic-dish antenna, something quite uncommon in the 1930s. In 1937, using his own funds, he constructed a 31.4-foot-diameter dish antenna in his back yard. The strange contraption attracted curious attention from his neighbors and became

  2. Monitoring Radio Frequency Interference in Southwest Virginia

    Science.gov (United States)

    Rapp, Steve

    2010-01-01

    The radio signals received from astronomical objects are extremely weak. Because of this, radio sources are easily shrouded by interference from devices such as satellites and cell phone towers. Radio astronomy is very susceptible to this radio frequency interference (RFI). Possibly even worse than complete veiling, weaker interfering signals can contaminate the data collected by radio telescopes, possibly leading astronomers to mistaken interpretations. To help promote student awareness of the connection between radio astronomy and RFI, an inquiry-based science curriculum was developed to allow high school students to determine RFI levels in their communities. The Quiet Skies Project_the result of a collaboration between the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and the National Radio Astronomy Observatory (NRAO)_encourages students to collect and analyze RFI data and develop conclusions as a team. Because the project focuses on electromagnetic radiation, it is appropriate for physics, physical science, chemistry, or general science classes. My class-about 50 students from 15 southwest Virginia high schools-participated in the Quiet Skies Project and were pioneers in the use of the beta version of the Quiet Skies Detector (QSD), which is used to detect RFI. Students have been involved with the project since 2005 and have collected and shared data with NRAO. In analyzing the data they have noted some trends in RFI in Southwest Virginia.

  3. Characterising Radio Emissions in Cosmic Filaments

    Science.gov (United States)

    Miller, R. O.

    2014-02-01

    A growing number of radio studies probe galaxy clusters into the low-power regime in which star formation is the dominant source of radio emission. However, at the time of writing no comparably deep observations have focused exclusively on the radio populations of cosmic filaments. This thesis describes the ATCA 2.1 GHz observations and subsequent analysis of two such regions - labelled Zone 1 (between clusters A3158 and A3125/A3128) and Zone 2 (between A3135 and A3145) - in the Horologium-Reticulum Supercluster (HRS). Source count profiles of both populations are discussed and a radio luminosity function for Zone 1 is generated. While the source counts of Zone 2 appear to be consistent with expected values, Zone 1 exhibits an excess of counts across a wide flux range (1 mJy< S_1.4 < 200 mJy). An excess in radio activity at the lower extent of this range (log P_1.4 < 22.5; within the SF-dominated regime) is also suggested by the radio luminosity function for that region, and brief colour analysis suggests that such an excess is indeed predominantly associated with a starforming population. The differences between the two filamentary zones is attributed to cosmic variation. The regions are both small (~ 1 degree square), and are significantly separated in the HRS. Further radio observations of filaments are required and the results combined into a larger sample size in order to arrive at a generalised model filamentary population.

  4. RADIO FLARES FROM GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Kopač, D.; Mundell, C. G.; Kobayashi, S.; Virgili, F. J. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool, L3 5RF (United Kingdom); Harrison, R. [Department of Astrophysics, School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Japelj, J.; Gomboc, A. [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Guidorzi, C. [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1, I-44122 Ferrara (Italy); Melandri, A., E-mail: D.Kopac@ljmu.ac.uk [INAF/Brera Astronomical Observatory, via Bianchi 46, I-23807, Merate (Italy)

    2015-06-20

    We present predictions of centimeter and millimeter radio emission from reverse shocks (RSs) in the early afterglows of gamma-ray bursts (GRBs) with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy, and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parameterization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. and Melandri et al. in which the typical frequency of the RS was suggested to lie at radio rather than optical wavelengths at early times, we show that the brightest and most distinct RS radio signatures are detectable up to 0.1–1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later optical peaks, high isotropic energies, lower circumburst medium densities, and at observing frequencies that are less prone to synchrotron self-absorption effects—typically above a few GHz. Given recent detections of polarized prompt gamma-ray and optical RS emission, we suggest that detection of polarized radio/millimeter emission will unambiguously confirm the presence of low-frequency RSs at early time.

  5. Deep radio images of the HEGRA and Whipple TeV sources in the Cygnus OB2 region.

    OpenAIRE

    Martí Ribas, Josep; Paredes i Poy, Josep Maria; Ishwara-Chandra, C. H.; Bosch i Ramon, Valentí

    2007-01-01

    The modern generation of Cherenkov telescopes has revealed a new population of gamma-ray sources in the Galaxy. Some of them have been identified with previously known X-ray binary systems while other remain without clear counterparts a lower energies. Our initial goal here was reporting on extensive radio observations of the first extended and yet unidentified source, namely TeV J2032+4130. This object was originally detected by the HEGRA telescope in the direction of the Cygnus OB2 region a...

  6. Amateur Planetary Radio Data Archived for Science and Education: Radio Jove

    Science.gov (United States)

    Thieman, J.; Cecconi, B.; Sky, J.; Garcia, L. N.; King, T. A.; Higgins, C. A.; Fung, S. F.

    2015-12-01

    The Radio Jove Project is a hands-on educational activity in which students, teachers, and the general public build simple radio telescopes, usually from a kit, to observe single frequency decameter wavelength radio emissions from Jupiter, the Sun, the galaxy, and the Earth usually with simple dipole antennas. Some of the amateur observers have upgraded their receivers to spectrographs and their antennas have become more sophisticated as well. The data records compare favorably to more sophisticated professional radio telescopes such as the Long Wavelength Array (LWA) and the Nancay Decametric Array. Since these data are often carefully calibrated and recorded around the clock in widely scattered locations they represent a valuable database useful not only to amateur radio astronomers but to the professional science community as well. Some interesting phenomena have been noted in the data that are of interest to the professionals familiar with such records. The continuous monitoring of radio emissions from Jupiter could serve as useful "ground truth" data during the coming Juno mission's radio observations of Jupiter. Radio Jove has long maintained an archive for thousands of Radio Jove observations, but the database was intended for use by the Radio Jove participants only. Now, increased scientific interest in the use of these data has resulted in several proposals to translate the data into a science community data format standard and store the data in professional archives. Progress is being made in translating Radio Jove data to the Common Data Format (CDF) and also in generating new observations in that format as well. Metadata describing the Radio Jove data would follow the Space Physics Archive Search and Extract (SPASE) standard. The proposed archive to be used for long term preservation would be the Planetary Data System (PDS). Data sharing would be achieved through the PDS and the Paris Astronomical Data Centre (PADC) and the Virtual Wave Observatory (VWO

  7. Simultaneous observations of solar sporadic radio emission by the radio telescopes UTR-2, URAN-2 and NDA within the frequency range 8-41MHz

    Science.gov (United States)

    Melnik, V. N.; Konovalenko, A. A.; Rucker, H. O.; Brazhenko, A. I.; Briand, C.; Dorovskyy, V. V.; Zarka, P.; Denis, L.; Bulatzen, V. G.; Frantzusenko, A. V.; Stanislavskyy, A. A.

    2012-04-01

    From 25 June till 12 August 2011 sporadic solar radio emission was observed simultaneously by three separate radio telescopes: UTR-2 (Kharkov, Ukraine), URAN-2 (Poltava, Ukraine) and NDA (Nancay, France). During these observations several type II bursts with double and triple harmonics were registered, as well as type II bursts with complex herringbone structure. The events of particular interest were type II bursts registered on 9 and 11 August 2011. These bursts had opposite sign of circular polarization at different parts of their dynamic spectra. In our opinion we registered the emissions, which came from the different parts of the shock propagating through the solar corona. We have observed also groups of type III bursts merged into one burst, type III bursts with triple harmonics and type III bursts with "split" polarization. In addition some unusual solar bursts were registered: storms of strange narrow-band (up to 500kHz) bursts with high polarization degree (about 80%), decameter spikes of extremely short durations (200-300ms), "tadpole-like" bursts with durations of 1-2s and polarization degree up to 60%.

  8. Parsec-scale radio structures in Quasars

    Science.gov (United States)

    Coldwell, G.; Paragi, Z.; Gurvits, L.

    Very Long Baseline Interferometry (VLBI) con su nueva extensión para el radio telescopio orbital, VSOP/HALCA, ofrece una incomparable resolución angular alcanzando escalas de milisegundos y submilisegundos de arco a longitudes de onda de centímetros. En este trabajo presentamos observaciones y análisis de estructuras en radio, en escalas de parsec, para 3 radio fuentes extragalácticas de la muestra de VSOP Survey y 1 quasar, 1442+101, del proyecto `VSOP High Redshift'.

  9. Nature of Coherent Radio Emission from Pulsars

    Science.gov (United States)

    Mitra, Dipanjan

    2017-09-01

    The pulsar radio emission originates from regions below 10% of the light cylinder radius. This requires a mechanism where coherent emission is excited in relativistic pair plasma with frequency ν _{cr} which is below the plasma frequency ν_{°} i.e. ν _{cr} charged bunches (charged solitons) moving relativistically along the curved open dipolar magnetic field lines capable of exciting coherent curvature radio emission. In this article, we review the results from high quality observations in conjunction with theoretical models to unravel the nature of coherent curvature radio emission in pulsars.

  10. Towards Non-spherical Radio Models

    Science.gov (United States)

    Ribeiro, V. A. R. M.; Steffen, W.; Chomiuk, L.; Koning, N.; O'Brien, T. J.; Woudt, P. A.

    2014-12-01

    Radio observations of novae in outburst are of particular interest due to the physical parameters that may be retrieved from fitting the radio light curves. Most models that have fitted previous data assumed spherical symmetry however, it is becoming more and more clear that this is not the case. We explore morpho-kinematical techniques to retrieve the free-free radio light curves of non-spherical models and explore the effects of a non-spherical outburst on the physical parameters. In particular, we find that we may have been over estimating the ejected masses in the outburst of non-spherical novae.

  11. Radio Channel State Prediction by Kalman Filter

    Directory of Open Access Journals (Sweden)

    Peter Ziacik

    2005-01-01

    Full Text Available In this article there is the description Kalman filter using as a radio channel state predictor. Simulator of prediction has been created in MATLAB environment and it is capable to simulate the prediction of radio signal envelope by Clark’s model of radio channel, which is implemented to the simulator. Simulations were realized for prediction range 0.41 ms and 6.24 ms and as comparing criterion we used the prediction error. It is clear from simulations, that with the duration of prediction the prediction error is enlarging, which may cause the erroneous decision of adaptation algorithms.

  12. Mobile radio channel as a complex medium

    DEFF Research Database (Denmark)

    Matic, Dusan; Prasad, Ramjee; Kalluri, Dikshitulu K.

    2001-01-01

    Optical fibres have almost unlimited capacity, but can not the address the users desire for mobility and ubiquitous access. The synergy of these two worlds can be seen in the direction of the Radio-over-Fibre. This paper presents to the reader an introduction for the mobile radio channel - basic...... physical phenomena, their implications on the transmitted signal, and how the radio channels are modelled. Special attention is given to the small-scale effects, such as multipath, and Rayleigh and Rice distributions of received signal, as these dominate in the case of indoor communication systems....

  13. Spectrum Management in Cognitive radio Networks

    OpenAIRE

    Marín Vinuesa, Lara

    2008-01-01

    Cognitive Radio es un nuevo paradigma en las comunicaciones wireless que tiene como objetivo aumentar la utilización del espectro, que hoy en día se encuentra saturado en ciertas bandas a causa del aumento de la demanda debida a la introducción de nuevas tecnologías. Cognitive Radio se define como un dispositivo que es capaz de extraer la información necesaria del entorno radio y modificar sus parámetros de transmisión con tal de utilizar de manera eficaz el espectro disponi...

  14. Cognitive Radio MAC Protocol for WLAN

    DEFF Research Database (Denmark)

    Zhang, Qi; Fitzek, Frank H.P.; Iversen, Villy Bæk

    2008-01-01

    To solve the performance degradation issue in current WLAN caused by the crowded unlicensed spectrum, we propose a cognitive radio (CR) media access protocol, C-CSMA/CA. The basic idea is that with cognitive radio techniques the WLAN devices can not only access the legacy WLAN unlicensed spectrum...... hole; moreover, it designs dual inband sensing scheme to detect primary user appearance. Additionally, C-CSMA/CA has the advantage to effectively solve the cognitive radio self-coexistence issues in the overlapping CR BSSs scenario. It also realizes station-based dynamic resource selection...

  15. Radio pill antenna range test

    Science.gov (United States)

    Cummins, W. F.; Kane, R. J.

    1992-05-01

    In order to investigate the potential of a proposed 'radio pill' beacon transmitter, a range test experiment was devised and carried out in the VHF frequency range. Calculations and previous work indicated that optimum sensitivity and, thus, distance would be obtained in this frequency range provided body radio-frequency (RF) absorption was not too great. A ferrite-core loop antenna is compatible with a pill geometry and has better radiation efficiency than an air core loop. The ferrite core may be a hollow cylinder with the electronics and batteries placed inside. However, this range test was only concerned with experimentally developing test range data on the ferrite core antenna itself. A one turn strap loop was placed around a 9.5 mm diameter by 18.3 mm long stack of ferrite cores. This was coupled to a 50 Omega transmission line by 76 mm of twisted pair line and a capacitive matching section. This assembly was excited by a signal generator at output levels of -10 to +10 dBm. Signals were received on a VHF receiver and tape recorder coupled to a 14 element, circularly polarized Yagi antenna at a height of 2.5 m. Field strength measurements taken at ranges of 440, 1100, and 1714 m. Maximum field strengths referenced to 0 dBm transmitter level were -107 to -110 dB at 440 m, -124 to -127 dBm at 1100 m, and -116 to -119 dBm at 1714 m when the antenna cylinder was horizontal. Field strengths with a vertical antenna were about 6 dB below these values. The latter transmit site was elevated and had a clear line-of-site path to the receiving site. The performance of this test antenna was better than that expected from method-of-moment field calculations. When this performance data is scaled to a narrow bandwidth receiving system, ground level receiving ranges of a few to 10 km can be expected. Clear line-of-sight ranges where either or both the transmitter and receiver are elevated could vary from several km to 100 km.

  16. Radio and Deep Chandra Observations of the Disturbed Cool Core Cluster Abell 133

    Science.gov (United States)

    Randall, S. W.; Clarke, T. E.; Nulsen, P. E. J.; Owers, M. S.; Sarazin, C. L.; Forman, W. R.; Murray, S. S.

    2010-10-01

    We present results based on new Chandra and multi-frequency radio observations of the disturbed cool core cluster Abell 133. The diffuse gas has a complex bird-like morphology, with a plume of emission extending from two symmetric wing-like features. The plume is capped with a filamentary radio structure that has been previously classified as a radio relic. X-ray spectral fits in the region of the relic indicate the presence of either high-temperature gas or non-thermal emission, although the measured photon index is flatter than would be expected if the non-thermal emission is from inverse Compton scattering of the cosmic microwave background by the radio-emitting particles. We find evidence for a weak elliptical X-ray surface brightness edge surrounding the core, which we show is consistent with a sloshing cold front. The plume is consistent with having formed due to uplift by a buoyantly rising radio bubble, now seen as the radio relic, and has properties consistent with buoyantly lifted plumes seen in other systems (e.g., M87). Alternatively, the plume may be a gas sloshing spiral viewed edge-on. Results from spectral analysis of the wing-like features are inconsistent with the previous suggestion that the wings formed due to the passage of a weak shock through the cool core. We instead conclude that the wings are due to X-ray cavities formed by displacement of X-ray gas by the radio relic. The central cD galaxy contains two small-scale cold gas clumps that are slightly offset from their optical and UV counterparts, suggestive of a galaxy-galaxy merger event. On larger scales, there is evidence for cluster substructure in both optical observations and the X-ray temperature map. We suggest that the Abell 133 cluster has recently undergone a merger event with an interloping subgroup, initialing gas sloshing in the core. The torus of sloshed gas is seen close to edge-on, leading to the somewhat ragged appearance of the elliptical surface brightness edge. We show

  17. Observational constraints on the radio and γ-ray emission regions of PSR B1055-52

    Science.gov (United States)

    Wang, H. G.; Qiao, G. J.; Xu, R. X.; Liu, Y.

    2006-03-01

    Observational constraints on the radio and γ-ray emission regions of PSR B1055-52 seen through our line of sight are presented by analysing the position angle curves of radio linear polarization and fitting the observed pulse widths of radio and γ-ray pulses and the phase offsets between them. Aberration, retardation and magnetic field sweep back effects that can cause additional phase offset between the emissions from different locations are taken into account. The following conclusions are obtained. (i) The radio main pulse and γ-ray pulses are emitted from the same pole, while the radio interpulse is emitted from the opposite pole. (ii) The interpulse emission region locates on the open field lines much closer to the magnetic axis than those of the main pulse, and the emission altitudes are higher than those of the main pulse. (iii) At each pole, there are probably two groups of field lines where radio emission is generated, of which the outer one consists of open field lines near (or including) the last open field lines and the inner one consists of open field lines from very near the magnetic pole to approximately the midway between the magnetic axis and the last open field lines. (iv) The γ-ray pulse comes from inner open field lines rather than from the last open field lines, and the emission altitudes are beyond the null charge surface.

  18. Decameter Type III Bursts with Changing Frequency Drift-Rate Signs

    Science.gov (United States)

    Melnik, V. N.; Brazhenko, A. I.; Konovalenko, A. A.; Briand, C.; Dorovskyy, V. V.; Zarka, P.; Frantsuzenko, A. V.; Rucker, H. O.; Rutkevych, B. P.; Panchenko, M.; Denis, L.; Zaqarashvili, T.; Shergelashvili, B.

    2015-01-01

    We discuss properties of type III bursts that change the sign of their drift rate from negative to positive and vice versa. Moreover, these bursts may change the sign of their drift rates more than once. These particular type III bursts were observed simultaneously by the radio telescopes UTR-2 ( Ukrainian T-shaped Radio telescope, Kharkov, Ukraine), URAN-2 ( Ukrainian Radio telescope of the Academy of Sciences, Poltava, Ukraine), and by the NDA ( Nançay Decametric Array, Nancay, France) in the frequency range 8 - 41 MHz. The negative drift rates of these bursts are similar to those of previously reported decameter type III bursts and vary from -0.7 MHz s-1 to -1.7 MHz s-1, but their positive drift rates vary in a wider range from 0.44 MHz s-1 to 6 MHz s-1. Unlike inverted U-bursts, the tracks of these type III bursts have C- or inverted C-shapes.

  19. Solar Micro-Type III Burst Storms and Long Dipolar Magnetic Field in the Outer Corona

    Science.gov (United States)

    Morioka, A.; Miyoshi, Y.; Iwai, K.; Kasaba, Y.; Masuda, S.; Misawa, H.; Obara, T.

    2015-08-01

    Solar micro-type III radio bursts are elements of the so-called type III storms and are characterized by short-lived, continuous, and weak emissions. Their frequency of occurrence with respect to radiation power is quite different from that of ordinary type III bursts, suggesting that the generation process is not flare-related, but due to some recurrent acceleration processes around the active region. We examine the relationship of micro-type III radio bursts with coronal streamers. We also explore the propagation channel of bursts in the outer corona, the acceleration process, and the escape route of electron beams. It is observationally confirmed that micro-type III bursts occur near the edge of coronal streamers. The magnetic field line of the escaping electron beams is tracked on the basis of the frequency drift rate of micro-type III bursts and the electron density distribution model. The results demonstrate that electron beams are trapped along closed dipolar field lines in the outer coronal region, which arise from the interface region between the active region and the coronal hole. A 22 year statistical study reveals that the apex altitude of the magnetic loop ranges from 15 to 50 RS. The distribution of the apex altitude has a sharp upper limit around 50 RS suggesting that an unknown but universal condition regulates the upper boundary of the streamer dipolar field.

  20. NAC/NINE Program Building Radio Jove's and Brining Radio Astronomy to the Community

    Science.gov (United States)

    Ramona Gallego, Angelina; Paul Gueye, Al Amin Kabir,

    2018-01-01

    During the course of the 8-week program, (NINE, National and International Non-Traditional Exchange Program), the summer was spent in Socorro, New Mexico, working on building a Radio Jove, and making observations with the Radio Jove as well as working on learning project management practices in order to take the CAPM PMI Exam. The NINE built the Radio Jove’s at the same time and in doing so learned to replicate it to teach it to others. The final portion of the program that was worked on was to create a NINE hub and do outreach with the community teaching them about radio astronomy and teaching students how to build their own Radio Jove’s and make observations. An important aspect of the summer program was to bring back the knowledge received about radio astronomy and teach it to high school students with the help of the institution each NINE participants came from.

  1. Optical and millimeter-wave radio seamless MIMO transmission based on a radio over fiber technology.

    Science.gov (United States)

    Kanno, Atsushi; Kuri, Toshiaki; Hosako, Iwao; Kawanishi, Tetsuya; Yoshida, Yuki; Yasumura, Yoshihiro; Kitayama, Ken-ichi

    2012-12-31

    Multi-input multi-output (MIMO) transmission of two millimeter-wave radio signals seamlessly converted from polarization-division-multiplexed quadrature-phase-shift-keying optical signals is successfully demonstrated, where a radio access unit basically consisting of only optical-to-electrical converters and a radio receiver performs total signal equalization of both the optical and the radio paths and demodulation with digital signal processing (DSP). Orthogonally polarized optical components that are directly converted to two-channel radio components can be demultiplexed and demodulated with high-speed DSP as in optical digital coherent detection. 20-Gbaud optical and radio seamless MIMO transmission provides a total capacity of 74.4 Gb/s with a forward error correction overhead of 7%.

  2. Gravitational Redshift Experiment with the Space Radio Telescope RadioAstron

    CERN Document Server

    Litvinov, D; Belousov, K; Bietenholz, M; Biriukov, A; Fionov, A; Gusev, A; Kauts, V; Kovalenko, A; Kulagin, V; Poraiko, N; Rudenko, V

    2015-01-01

    A unique test of general relativity is possible with the space radio telescope RadioAstron. The ultra-stable on-board hydrogen maser frequency standard and the highly eccentric orbit make RadioAstron an ideal instrument for probing the gravitational redshift effect. Large gravitational potential variation, occurring on the time scale of $\\sim$24 hr, causes large variation of the on-board H-maser clock rate, which can be detected via comparison with frequency standards installed at various ground radio astronomical observatories. The experiment requires specific on-board hardware operating modes and support from ground radio telescopes capable of tracking the spacecraft continuously and equipped with 8.4 or 15 GHz receivers. Our preliminary estimates show that $\\sim$30 hr of the space radio telescope's observational time are required to reach $\\sim 2\\times10^{-5}$ accuracy in the test, which would constitute a factor of 10 improvement over the currently achieved best result.

  3. Radio as the Voice of God: Peace and Tolerance Radio Programming’s Impact on Norms

    OpenAIRE

    Daniel P. Aldrich

    2012-01-01

    Observers have argued that radio programming can alter norms, especially through hate radio designed to increase animosity between groups. This article tests whether or not radio programming under the Countering Violent Extremism (CVE) policy framework can reduce potential conflict and increase civic engagement and positive views of foreign nations. Data from surveys of more than 1,000 respondents in Mali, Chad, and Niger illuminate the ways in which peace and tolerance programming changed pe...

  4. A RADIO-SELECTED BLACK HOLE X-RAY BINARY CANDIDATE IN THE MILKY WAY GLOBULAR CLUSTER M62

    Energy Technology Data Exchange (ETDEWEB)

    Chomiuk, Laura; Ransom, Scott [National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA (United States); Strader, Jay [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Maccarone, Thomas J. [Department of Physics, Texas Tech University, Box 41051, Lubbock, TX 79409-1051 (United States); Miller-Jones, James C. A. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia); Heinke, Craig [Department of Physics, University of Alberta, 4-183 CCIS, Edmonton, AB T6G 2E1 (Canada); Noyola, Eva [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico (UNAM), A. P. 70-264, 04510 (Mexico); Seth, Anil C., E-mail: chomiuk@pa.msu.edu [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States)

    2013-11-01

    We report the discovery of a candidate stellar-mass black hole in the Milky Way globular cluster M62. We detected the black hole candidate, which we call M62-VLA1, in the core of the cluster using deep radio continuum imaging from the Karl G. Jansky Very Large Array. M62-VLA1 is a faint source with a flux density of 18.7 ± 1.9 μJy at 6.2 GHz and a flat radio spectrum (α = –0.24 ± 0.42, for S{sub ν} = ν{sup α}). M62 is the second Milky Way cluster with a candidate stellar-mass black hole; unlike the two candidate black holes previously found in the cluster M22, M62-VLA1 is associated with a Chandra X-ray source, supporting its identification as a black hole X-ray binary. Measurements of its radio and X-ray luminosity, while not simultaneous, place M62-VLA1 squarely on the well-established radio-X-ray correlation for stellar-mass black holes. In archival Hubble Space Telescope imaging, M62-VLA1 is coincident with a star near the lower red giant branch. This possible optical counterpart shows a blue excess, Hα emission, and optical variability. The radio, X-ray, and optical properties of M62-VLA1 are very similar to those for V404 Cyg, one of the best-studied quiescent stellar-mass black holes. We cannot yet rule out alternative scenarios for the radio source, such as a flaring neutron star or background galaxy; future observations are necessary to determine whether M62-VLA1 is indeed an accreting stellar-mass black hole.

  5. Software Defined Multiband EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of Phase 2 is to build a reliable, lightweight, programmable, multi-mode, miniaturized EVA Software Defined Radio (SDR) that supports data telemetry,...

  6. Software Defined Multiband EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this research is to propose a reliable, lightweight, programmable, multi-band, multi-mode, miniaturized frequency-agile EVA software defined radio...

  7. Cognitive Radio Networks From Theory to Practice

    CERN Document Server

    Khattab, Ahmed; Bayoumi, Magdy

    2013-01-01

    This book describes a communication paradigm that could shape the future of wireless communication networks, Opportunistic Spectrum Access (OSA) in Cognitive Radio Networks (CRN).  While several theoretical OSA approaches have been proposed, they are challenged by the practical limitations of cognitive radios: the key enabling technology of OSA.  This book presents an unprecedented formulation of the OSA problem in CNR that takes into account the practical limitations encountered due to existing technologies. Based on such a problem formulation, this book presents a framework and protocol details implementing the analytically-optimized solution of this problem. Unlike the state-of-the-art of CRN implementations that typically target software define radios which are not suitable for real systems, this book describes the implementation of distributed OSA, using practical radio transceiver technologies. It provides a thorough characterization of the gains available to theoretical OSA approaches if the practica...

  8. 75 FR 66709 - Commercial Radio Operators Rules

    Science.gov (United States)

    2010-10-29

    ... satisfactory explanation of the delay. Upon receipt by the Commission of such application for hearing, said... license(s) indicated in parentheses. (1) Ship Radar Endorsement (Radiotelegraph Operator Certificate... Operator License, Marine Radio Operator Permit, Radiotelegraph Operator's Certificate, Ship Radar...

  9. Reconfigurable, Cognitive Software Defined Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Intelligent Automation Inc, (IAI) is currently developing a software defined radio (SDR) platform that can adaptively switch between different modes of operation for...

  10. Reconfigurable Power-Aware EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Extra Vehicular Activity (EVA) radio system is a pivotal technology for the successful support of the International Space Station beyond 2020 and future...

  11. Faint radio sources and gravitational lensing

    Energy Technology Data Exchange (ETDEWEB)

    Langston, G.I.; Conner, S.R.; Heflin, M.B.; Lehar, J.; Burke, B.F. (E. O. Hulburt Center for Space Research, Washington, DC (USA) MIT, Cambridge, MA (USA))

    1990-04-01

    Measurements of the surface density of radio sources resulting from a deep VLA integration at 5 GHz and the MIT-Green Bank (MG) II 5 GHz survey are summarized. The faint source counts are combined with previous observations and fitted to a power-law function of surface density vs. limiting flux density. The surface density of radio sources brighter than 1 mJy is k = 0.019 + or - 0.004/arcmin. The power-law exponent is best fit by -0.93 + or - 0.14. Between 15 and 100 mJy, the surface density of radio sources varies nearly as predicted by Euclidian models of the universe. Estimates are given for the number of chance alignments of radio sources in the VLA snapshot observations of the MIT-Princeton-Caltech gravitational lens search. The probability of lens candidate configurations occurring by chance alignment is calculated. 28 refs.

  12. Radio VLBI and the quantum interference paradox

    CERN Document Server

    Singal, Ashok K

    2016-01-01

    We address here the question of interference of radio signals from astronomical sources like distant quasars, in a very long baseline interferometer (VLBI), where two (or more) distantly located radio telescopes (apertures), receive simultaneous signal from the sky. In an equivalent optical two-slit experiment, it is generally argued that for the photons involved in the interference pattern on the screen, it is not possible, even in principle, to ascertain which of the two slits a particular photon went through. It is argued that any procedure to ascertain this destroys the interference pattern. But in the case of the modern radio VLBI, it is a routine matter to record the phase and amplitude of the voltage outputs from the two radio antennas on a recording media separately and then do the correlation between the two recorded signals later in an offline manner. Does this not violate the quantum interference principle? We provide a resolution of this problem here.

  13. Reconfigurable, Cognitive Software Defined Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — IAI is actively developing Software Defined Radio platforms that can adaptively switch between different modes of operation by modifying both transmit waveforms and...

  14. Distortion mitigation in cognitive radio receivers

    NARCIS (Netherlands)

    Mahrof, D.H.

    2015-01-01

    The exponential increase of wireless communication increasingly leads to spectrum congestion. Attempts are being made to increase RF spectrum utilization efficiency by introducing Cognitive Radio (CR) concept. A CR tries to intelligently solve the congestion problem via Dynamic Spectrum Access

  15. The future of Canada's radio astronomy

    Science.gov (United States)

    Gaensler, Bryan M.

    2017-11-01

    Through involvement in CHIME, ALMA, the Jansky VLA and the Murchison Widefield Array, Canada is well placed in current radio astronomy facilities and the future looks even brighter, with strategic interest in the SKA and the Next Generation VLA.

  16. Rail-CR : railroad cognitive radio.

    Science.gov (United States)

    2012-12-01

    Robust, reliable, and interoperable wireless communication devices or technologies are vital to the success of positive train control (PTC) systems. Accordingly, the railway industry has started adopting software-defined radios (SDRs) for packet-data...

  17. Improved fire resistant radio frequency anechoic materials

    Science.gov (United States)

    Robinson, D. A.

    1969-01-01

    Protective, flameproof foam covering improves the resistance to fire and surface contamination of low-cost radio frequency absorbing and shielding anechoic materials. This promotes safety of operating personnel and equipment being tested in an otherwise combustible anechoic chamber.

  18. A statistical study of solar type III bursts and auroral kilometric radiation onsets

    Science.gov (United States)

    Farrell, W. M.; Gurnett, D. A.

    1985-01-01

    Simultaneous occurrences of type III solar radio bursts and auroral kilometric radiation were observed by Calvert (1981) using ISEE 1 spectrograms. Calvert presented evidence suggesting that the incoming type III burst stimulates the onset of auroral kilometric radiation (AKR). This paper presents a statistical study of the correlation between type III bursts and auroral kilometric radiation. A superposed epoch analysis was performed on as many as 186 type III events. The type III bursts were detected by the ISEE 3 spacecraft on the sunward side of the earth. At the same time the IMP 8 spacecraft was used to detect onsets of kilometric radiation on the nightside of the earth. For each event the intensities measured by ISEE 3 (type III intensities) were subtracted from the intensities measured by IMP 8 (type III and possible AKR intensities). The resulting intensities for each event were then added to determine if kilometric radiation was preferentially observed following a type III burst. This analysis was performed at frequencies of 100, 178, and 500 kHz. The results of this study show that a statistically significant correlation exists between incoming type III bursts from the sun and kilometric radiation from the earth.

  19. 47 CFR 2.107 - Radio astronomy station notification.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Radio astronomy station notification. 2.107....107 Radio astronomy station notification. (a) Pursuant to No. 1492 of Article 13 and Section F of Appendix 3 to the international Radio Regulations (Geneva, 1982), operators of radio astronomy stations...

  20. 75 FR 63431 - Radio Broadcasting Services; Willow Creek, CA

    Science.gov (United States)

    2010-10-15

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Willow Creek, CA AGENCY: Federal Communications... 47 CFR Part 73 Radio, Radio broadcasting. For the reasons discussed in the preamble, the Federal Communications Commission proposes to amend 47 CFR part 73 as follows: PART 73--RADIO BROADCAST SERVICES 1. The...