WorldWideScience

Sample records for nearby x-shaped radio

  1. THE GENESIS OF MORPHOLOGIES IN EXTENDED RADIO SOURCES: X-SHAPES, OFF-AXIS DISTORTIONS, AND GIANT RADIO SOURCES

    International Nuclear Information System (INIS)

    Saripalli, Lakshmi; Subrahmanyan, Ravi

    2009-01-01

    We examine relationships between the morphology in double radio sources and the radio-optical position angle offset-the relative orientation of the radio axis with respect to the major axis of the host galaxy. The study was done for a representative sample of radio sources, the nearby (redshift z < 0.5) 3CRR sources, and separately for samples of giant radio sources and X-shaped radio sources. We find that radio morphological features have a dependence on the radio-optical position angle offset and on whether the source is a major- or minor-axis source. The evidence indicates an anisotropic gas environment, related to the ellipticity of the host galaxy, that causes the source linear size evolution, strength of backflow in the radio lobes, off-axis lobe distortions and the formation of wings, and X-shaped radio sources to depend on the radio-optical position angle offset. We identify a class of X-shaped radio sources, which are either edge-darkened or lacking hotspots, and appear to have inner doubles suggesting a restarting of activity. We suggest a common formation mechanism, requiring backflows, for these apparently FR-I X-shaped radio sources as well as the edge-brightened X-shaped sources.

  2. FIRST "WINGED" AND X-SHAPED RADIO SOURCE CANDIDATES. II. NEW REDSHIFTS

    NARCIS (Netherlands)

    Cheung, C. C.; Healey, Stephen E.; Landt, Hermine; Kleijn, Gijs Verdoes; Jordan, Andres

    We report optical spectroscopic observations of X-shaped radio sources with the Hobby-Eberly Telescope and Multiple-Mirror Telescope, focused on the sample of candidates from the FIRST survey presented in a previous paper. A total of 27 redshifts were successfully obtained, 21 of which are new,

  3. The Nuclei of Nearby Radio-Loud Galaxies with HST

    Science.gov (United States)

    Verdoes Kleijn, G. A.; Baum, S. A.; de Zeeuw, P. T.

    2001-12-01

    I report on a study of the central regions in 21 nearby (v constraints on its Doppler boosting. The active nuclei of nearby elliptical galaxies which do not harbor large scale radio jets seem to follow similar correlations. HST/STIS spectroscopy was used to map the kinematics and emission-line ratios of the central emission-line gas. I report on the results from dynamical modeling to measure black hole masses. Thus, main conclusions of this study are: (i) there is no photometric indication that the activity in nearby elliptical galaxies is triggered by specific properties of the central stellar distributions, and (ii) there appears to be a continuous sequence in the properties of the radio-loud and quiet active nuclei in nearby elliptical galaxies. Financial support for this work was provided by NASA/STScI and Leiden Observatory.

  4. From Nearby Low Luminosity AGN to High Redshift Radio Galaxies ...

    Indian Academy of Sciences (India)

    Review. J. Astrophys. Astr. (2016) 37: 34. DOI: 10.1007/s12036-016-9411-z. From Nearby Low Luminosity AGN to High Redshift Radio. Galaxies: Science Interests with Square Kilometre Array. P. Kharb1,2,∗, D. V. Lal1, ..... action or past merger. So far, J0315−1906, ..... Approximately half of the baryons in the present day ...

  5. Chandra Studies of Nearby Radio and Seyfert Galaxies

    Science.gov (United States)

    Wilson, A. S.

    2001-09-01

    I shall describe some of the results of a Chandra ACIS program on the extended, universally bi-polar, X-ray emission of nearby radio galaxies and Seyfert galaxies, with emphasis on the diversity of the radiation mechanisms involved and the implications for our understanding of the AGN phenomenon. a) Radio galaxies. The X-ray emission from the hot spots of Cygnus A are synchrotron self-Compton emission from the synchrotron radio emitting electrons in a magnetic field which is close to equipartition (the papers by Young et al. and Smith et al. describe our Chandra results on the nucleus and cluster gas of Cygnus A, respectively). The X-ray knots of the M87 jet are almost certainly synchrotron radiation, as judged by their steep spectra. Preliminary results of a long integration on the Virgo cluster ICM will be presented. The X-ray radiation mechanism of the jet and western hot spot of Pictor A remains uncertain, with evidence favoring synchrotron radiation and bulk relativistic outflow of the jet and, remarkably, the western hot spot. b) Seyfert galaxies. For the Circinus galaxy, NGC 1068 and NGC 4151, the bulk of the X-ray emitting gas is photoionized by the nucleus. There is some evidence for thermal plasma emission powered by the starburst in Circinus and by the jet-driven outflows in NGC 1068. In M51, the bi-polar nuclear lobes previously found in radio continuum and optical line emission show up in X-rays as thermal plasma emission from shocked gas with kT ~ 0.5 keV. The nucleus is obscured by a column density in excess of 1024 cm-2 (see paper by Terashima et al.). In NGC 4258, the X-rays (which are thermal plasma emission from gas with kT ~ 0.3 - 0.6 keV) are dominated by the ``anomalous arms''. These arms represent dense gas in the galaxy disk shocked by mass motions driven into the low density halo gas (which then collides with the disk) by the out-of-disk radio jet. The extended X-ray emission powered by active galaxies thus depends on the relative

  6. Radio, optical and X-ray nuclei in nearby 3CRR radio galaxies

    OpenAIRE

    Hardcastle, M. J.; Worrall, D. M.

    1999-01-01

    HST observations have shown that low-redshift 3CR radio galaxies often exhibit a point-like optical component positionally coincident with the GHz-frequency radio core. In this paper we discuss the correlation between the luminosities of the radio, optical and X-ray cores in these objects, and argue that all three components have a common origin at the base of the relativistic jets. In unified models, FRI radio galaxies should appear as dimmed, redshifted versions of BL Lac objects. We show t...

  7. Radio halos in nearby (z < 0.4) clusters of galaxies

    OpenAIRE

    Giovannini, G.; Bonafede, A.; Feretti, L.; Govoni, F.; Murgia, M.; Ferrari, F.; Monti, G.

    2009-01-01

    The Intra-Cluster Medium is characterized by thermal emission, and by the presence of large scale magnetic fields. In some clusters of galaxies a diffuse non-thermal emission is also present, located at the cluster center and named radio halo. These sources indicate the existence of relativistic particles and magnetic fields in the cluster volume. In this paper we collect data on all known nearby cluster radio halos (z < 0.4), to discuss their statistical properties and to investigate their o...

  8. ROSAT Observations of a Complete Nearby Sample of Low Luminosity Radio Galaxies

    Science.gov (United States)

    Baum, Stefi

    2001-01-01

    We are studying the X-ray emission in a sample of nearby radio galaxies. The X-rays probe several important components: (1) the active galactic nuclei; (2) the interstellar medium of the host galaxy; and (3) the intergalactic or intracluster medium through which the jets propagate. The interaction of the radio plasma with the hot ambient gas will allow us to constrain the properties of the environments and the energetics of the radio source propagation. We have made excellent progress reducing the ROSAT new and archival data on our complete sample of nearby radio galaxies. The data reduction has taken longer than originally anticipated because we have identified bubbles of x-ray emission around many of the central galaxies and we have been exploring many different methodologies for assuring the results are robust before we publish and complete our interpretation. We have now begun the final phases of the work, with a draft paper under construction and a planned for submission date of early 2001. This work comprises 1/3 of the thesis work of a graduate student and will be the final phase in the completion of the thesis.

  9. High-energy gamma rays and neutrinos from nearby radio galaxies

    Science.gov (United States)

    Blanco, Carlos; Hooper, Dan

    2017-12-01

    Multi-messenger data suggest that radio galaxies (ie non-blazar active galaxies) are a well-motivated class of sources for the diffuse flux of high-energy neutrinos reported by the IceCube Collaboration. In this study, we consider the gamma-ray spectrum observed from four nearby radio galaxies (Centaurus A, PKS 0625-35, NGC 1275 and IC 310) and constrain the intensity and spectral shape of the emission injected from these sources, accounting for the effects of attenuation and contributions from electromagnetic cascades (initiated both within the radio galaxy itself and during extragalactic propagation). Assuming that this gamma-ray emission is generated primarily through the interactions of cosmic-ray protons with gas, we calculate the neutrino flux predicted from each of these sources. Although this scenario is consistent with the constraints published by the IceCube and ANTARES Collaborations, the predicted fluxes consistently fall within an order of magnitude of the current point source sensitivity. The prospects appear very encouraging for the future detection of neutrino emission from the nearest radio galaxies.

  10. Radio haloes in nearby galaxies modelled with 1D cosmic ray transport using SPINNAKER

    Science.gov (United States)

    Heesen, V.; Krause, M.; Beck, R.; Adebahr, B.; Bomans, D. J.; Carretti, E.; Dumke, M.; Heald, G.; Irwin, J.; Koribalski, B. S.; Mulcahy, D. D.; Westmeier, T.; Dettmar, R.-J.

    2018-05-01

    We present radio continuum maps of 12 nearby (D ≤ 27 Mpc), edge-on (i ≥ 76°), late-type spiral galaxies mostly at 1.4 and 5 GHz, observed with the Australia Telescope Compact Array, Very Large Array, Westerbork Synthesis Radio Telescope, Effelsberg 100-m, and Parkes 64-m telescopes. All galaxies show clear evidence of radio haloes, including the first detection in the Magellanic-type galaxy NGC 55. In 11 galaxies, we find a thin and a thick disc that can be better fitted by exponential rather than Gaussian functions. We fit our SPINNAKER (SPectral INdex Numerical Analysis of K(c)osmic-ray Electron Radio-emission) 1D cosmic ray transport models to the vertical model profiles of the non-thermal intensity and to the non-thermal radio spectral index in the halo. We simultaneously fit for the advection speed (or diffusion coefficient) and magnetic field scale height. In the thick disc, the magnetic field scale heights range from 2 to 8 kpc with an average across the sample of 3.0 ± 1.7 kpc; they show no correlation with either star formation rate (SFR), SFR surface density (ΣSFR), or rotation speed (Vrot). The advection speeds range from 100 to 700 km s - 1 and display correlations of V∝SFR0.36 ± 0.06 and V∝ Σ _SFR^{0.39± 0.09}; they agree remarkably well with the escape velocities (0.5 ≤ V/Vesc ≤ 2), which can be explained by cosmic ray-driven winds. Radio haloes show the presence of disc winds in galaxies with ΣSFR > 10 - 3 M⊙ yr - 1 kpc - 2 that extend over several kpc and are driven by processes related to the distributed star formation in the disc.

  11. Kinematics and physical conditions of H I in nearby radio sources. The last survey of the old Westerbork Synthesis Radio Telescope

    NARCIS (Netherlands)

    Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.; Geréb, K.; Maddox, N.

    2017-01-01

    We present an analysis of the properties of neutral hydrogen (H I) in 248 nearby (0.02 radio galaxies with S1.4 GHz > 30 mJy and for which optical spectroscopy is available. The observations were carried out with the Westerbork Synthesis Radio Telescope as the last large project before the

  12. A search for candidate radio supernova remnants in the nearby irregular starburst galaxies NGC 4214 and NGC 4395

    Directory of Open Access Journals (Sweden)

    Vukotić B.

    2005-01-01

    Full Text Available We present the results of a search for new candidate radio su­pernova remnants (SNRs in the nearby starburst irregular galaxies NGC 4214 and NGC 4395 using archived radio observations made with the Very Large Array (VLA at the wavelengths of 3.5 cm, 6 cm and 20 cm for NGC 4214 and 6 cm and 20 cm for NGC 4395. These observations were analyzed as part of our ongoing search for candidate radio SNRs in nearby galaxies: the goal of this search is to prepare a large sample of candidate radio SNRs for the purpose of a robust statistical study of the properties of these sources. Based on our analysis, we have confirmed the nonthermal nature of the discrete radio sources α and β in NGC 4214 and classify these sources as candidate radio SNRs based on their positional coincidences with HII regions in that galaxy. We have measured the flux densities of the two candidate radio SNRs at each wavelength and calculated corresponding spectral indices: we have also measured flux densities of two other discrete radio sources in these galaxies - ρ in NGC 4214 and #3 in NGC 4395 which we suspect to be additional candidate radio SNRs based on their positional coincidences with other HII regions in these galaxies. However, the radio data presently available for these sources can­not confirm such a classification and additional observations are needed. We have also calculated the radio luminosities Lradio at the wavelength of 20 cm for these two candidate radio SNRs as well as the corresponding values for the minimum total energy Emin required to power these radio sources via synchrotron emission and the corresponding magnetic field strength Bmin. We have compared our mean calculated values for these properties with the mean values for populations of candidate radio SNRs in other starburst galaxies: while the values for Lradio and Bmin are roughly comparable to the values seen in other starburst galaxies, the mean value for Emin is higher than the mean value of any

  13. VizieR Online Data Catalog: Radio haloes in nearby galaxies (Heesen+, 2018)

    Science.gov (United States)

    Heesen, V.; Krause, M.; Beck, R.; Adebahr, B.; Bomans, D. J.; Carretti, E.; Dumke, M.; Heald, G.; Irwin, J.; Koribalski, B. S.; Mulcahy, D. D.; Westmeier, T.; Dettmar, R.-J.

    2018-02-01

    We present radio continuum observations of 12 nearby (D=2-27Mpc) edge-on galaxies at two different frequencies, namely at 1.4 and 5GHz (one galaxy at 8.5GHz instead of 5GHz). Our sample includes 11 late-type spiral (Sb or Sc) galaxies and one Magellanic-type barred galaxy (SBm), which are all highly inclined (i>=76°). As part of our study we have obtained several additional radio continuum maps. We make these maps publicly available (as well as all the other radio continuum maps in the paper). For 4 galaxies (NGC 55, 253, 891 and 4631) we have used single-dish maps, to correct for the missing zero-spacing flux where necessary. The Effelsberg maps of NGC 253 and 4631 were already presented in Heesen et al. (2009A&A...494..563H) and Mora & Krause (2013A&A...560A..42M), respectively, and the Effelsberg map of NGC 891 was already presented in Dumke (1997, PhD thesis, University of Bonn). We present these maps for completeness. The 4.80-GHz map of NGC 55 obtained with the 64-m Parkes telescope is so far unpublished. Furthermore, we show two maps of NGC 4631 at 1.35 and 1.65GHz observed with the VLA in D- configuration (R. Beck 2016, priv. comm.). The data were observed in August 1996, with 12 h on-source (ID: AG486) and reduced in standard fashion with AIPS. The maps have an angular resolution of 52 arcsec, so that we did not use them in the analysis, but they also show the halo of this galaxy very well. Lastly, we obtained maps of three further edge-on galaxies observed with the VLA (NGC 4157, 4217 and 4634). We reduced the data as described in Section 2, but since we had only one frequency available and no spectral index map, we did not use them in the analysis. The maps of NGC 4157 and 4217 were created by re-reducing archive data (IDs AI23, AF85, AH457 and AS392 for NGC 4157 and ID AM573 for NGC 4217). The map of NGC 4634 was created by using so far unpublished data from the VLA (ID: AD538). (3 data files).

  14. Kinematics and physical conditions of H I in nearby radio sources. The last survey of the old Westerbork Synthesis Radio Telescope

    Science.gov (United States)

    Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.; Geréb, K.; Maddox, N.

    2017-08-01

    We present an analysis of the properties of neutral hydrogen (H I) in 248 nearby (0.02 30 mJy and for which optical spectroscopy is available. The observations were carried out with the Westerbork Synthesis Radio Telescope as the last large project before the upgrade of the telescope with phased array feed receivers (Apertif). The sample covers almost four orders of magnitude in radio power from log P1.4 GHz = 22.5 W Hz-1 and 26.2 W Hz-1. We detect H I in absorption in 27% ± 5.5% of the objects. The detections are found over the full range of radio power. However, the distribution and kinematics of the absorbing H I gas appear to depend on radio power, the properties of the radio continuum emission, and the dust content of the sources. Among the sources where H I is detected, gas with kinematics deviating from regular rotation is more likely found as the radio power increases. In the great majority of these cases, the H I profile is asymmetric with a significant blue-shifted component. This is particularly common for sources with log P1.4 GHz > 24 W Hz-1, where the radio emission is small, possibly because these radio sources are young. The same is found for sources that are bright in the mid-infrared, I.e. sources rich in heated dust. In these sources, the H I is outflowing likely under the effect of the interaction with the radio emission. Conversely, in dust-poor galaxies, and in sources with extended radio emission, at all radio powers we only detect H I distributed in a rotating disk. Stacking experiments show that in sources for which we do not detect H I in absorption directly, the H I has a column density that is lower than 3.5 × 1017 (Tspin/cf) cm-2. We use our results to predict the number and type of H I absorption lines that will be detected by the upcoming surveys of the Square Kilometre Array precursors and pathfinders (Apertif, MeerKAT, and ASKAP).

  15. VizieR Online Data Catalog: HI in nearby radio sources (Maccagni+, 2017)

    Science.gov (United States)

    Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.; Gereb, K.; Maddox, N.

    2017-10-01

    We expand the sample of radio sources presented in Gereb et al. (2014A&A...569A..35G, hereafter G14) and Gereb et al. (2015, Cat. J/A+A/575/A44, hereafter G15) to lower radio fluxes and radio powers. As in those studies, we selected the sources by cross-correlating the seventh data release of the Sloan Digital Sky Survey catalogue (SDSS DR7; York et al. 2000AJ....120.1579Y) with the Faint Images of the Radio Sky at Twenty-cm catalogue (FIRST; Becker et al. 1995ApJ...450..559B, See Cat. VIII/92). The sources lie above declination DE>10° and between 07h51m00s and 17h22m25s in right ascension. The sources are restricted to the redshift range 0.02file).

  16. LOFAR reveals the giant: a low-frequency radio continuum study of the outflow in the nearby FR I radio galaxy 3C 31

    Science.gov (United States)

    Heesen, V.; Croston, J. H.; Morganti, R.; Hardcastle, M. J.; Stewart, A. J.; Best, P. N.; Broderick, J. W.; Brüggen, M.; Brunetti, G.; ChyŻy, K. T.; Harwood, J. J.; Haverkorn, M.; Hess, K. M.; Intema, H. T.; Jamrozy, M.; Kunert-Bajraszewska, M.; McKean, J. P.; Orrú, E.; Röttgering, H. J. A.; Shimwell, T. W.; Shulevski, A.; White, G. J.; Wilcots, E. M.; Williams, W. L.

    2018-03-01

    We present a deep, low-frequency radio continuum study of the nearby Fanaroff-Riley class I (FR I) radio galaxy 3C 31 using a combination of LOw Frequency ARray (LOFAR; 30-85 and 115-178 MHz), Very Large Array (VLA; 290-420 MHz), Westerbork Synthesis Radio Telescope (WSRT; 609 MHz) and Giant Metre Radio Telescope (GMRT; 615 MHz) observations. Our new LOFAR 145-MHz map shows that 3C 31 has a largest physical size of 1.1 Mpc in projection, which means 3C 31 now falls in the class of giant radio galaxies. We model the radio continuum intensities with advective cosmic ray transport, evolving the cosmic ray electron population and magnetic field strength in the tails as functions of distance to the nucleus. We find that if there is no in situ particle acceleration in the tails, then decelerating flows are required that depend on radius r as v∝rβ (β ≈ -1). This then compensates for the strong adiabatic losses due to the lateral expansion of the tails. We are able to find self-consistent solutions in agreement with the entrainment model of Croston & Hardcastle, where the magnetic field provides ≈1/3 of the pressure needed for equilibrium with the surrounding intracluster medium. We obtain an advective time-scale of ≈190 Myr, which, if equated to the source age, would require an average expansion Mach number M ≈ 5 over the source lifetime. Dynamical arguments suggest that instead either the outer tail material does not represent the oldest jet plasma or else the particle ages are underestimated due to the effects of particle acceleration on large scales.

  17. Early Radio and X-Ray Observations of the Youngest Nearby Type Ia Supernova PTF 11kly (SN 2011fe)

    Science.gov (United States)

    Horesh, Assaf; Kulkarni, S. R.; Fox, Derek B.; Carpenter, John; Kasliwal, Mansi M.; Ofek, Eran O.; Quimby, Robert; Gal-Yam, Avishay; Cenko, S. Bradley; deBruyn, A. G.; hide

    2012-01-01

    On August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time. We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of M(raised dot) less than or equal to 10(exp -8) (w /100 kilometers per second ) solar mass yr(exp -1) from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations we would have to wait for a long time (decade or longer) in order to more meaningfully probe the circumstellar matter of Ia supernovae.

  18. LeMMINGs - I. The eMERLIN legacy survey of nearby galaxies. 1.5-GHz parsec-scale radio structures and cores

    Science.gov (United States)

    Baldi, R. D.; Williams, D. R. A.; McHardy, I. M.; Beswick, R. J.; Argo, M. K.; Dullo, B. T.; Knapen, J. H.; Brinks, E.; Muxlow, T. W. B.; Aalto, S.; Alberdi, A.; Bendo, G. J.; Corbel, S.; Evans, R.; Fenech, D. M.; Green, D. A.; Klöckner, H.-R.; Körding, E.; Kharb, P.; Maccarone, T. J.; Martí-Vidal, I.; Mundell, C. G.; Panessa, F.; Peck, A. B.; Pérez-Torres, M. A.; Saikia, D. J.; Saikia, P.; Shankar, F.; Spencer, R. E.; Stevens, I. R.; Uttley, P.; Westcott, J.

    2018-05-01

    We present the first data release of high-resolution (≤0.2 arcsec) 1.5-GHz radio images of 103 nearby galaxies from the Palomar sample, observed with the eMERLIN array, as part of the LeMMINGs survey. This sample includes galaxies which are active (low-ionization nuclear emission-line regions [LINER] and Seyfert) and quiescent (H II galaxies and absorption line galaxies, ALGs), which are reclassified based upon revised emission-line diagrams. We detect radio emission ≳0.2 mJy for 47/103 galaxies (22/34 for LINERS, 4/4 for Seyferts, 16/51 for H II galaxies, and 5/14 for ALGs) with radio sizes typically of ≲100 pc. We identify the radio core position within the radio structures for 41 sources. Half of the sample shows jetted morphologies. The remaining half shows single radio cores or complex morphologies. LINERs show radio structures more core-brightened than Seyferts. Radio luminosities of the sample range from 1032 to 1040 erg s-1: LINERs and H II galaxies show the highest and lowest radio powers, respectively, while ALGs and Seyferts have intermediate luminosities. We find that radio core luminosities correlate with black hole (BH) mass down to ˜107 M⊙, but a break emerges at lower masses. Using [O III] line luminosity as a proxy for the accretion luminosity, active nuclei and jetted H II galaxies follow an optical Fundamental Plane of BH activity, suggesting a common disc-jet relationship. In conclusion, LINER nuclei are the scaled-down version of FR I radio galaxies; Seyferts show less collimated jets; H II galaxies may host weak active BHs and/or nuclear star-forming cores; and recurrent BH activity may account for ALG properties.

  19. FINITE-ELEMENT MODELING OF WELDED X-SHAPED JOINT

    Directory of Open Access Journals (Sweden)

    V. V. Kyzniatsova

    2014-01-01

    Full Text Available The paper presents a modeling of non-stationary processes while making arc welding in the shielding gas medium of X-shaped joints which consist of re-bars having various diameters. Changes and specific features of stress-strain state in the X-shaped joint have been considered in the paper. Calculations are as much as possible approximated to a real situation: a 3D-geometrical and finite-element model is used, the problem is considered as elastic and contact one with due account of power loading. An analysis of the welded assembly consisting of re-bars with diameter of 4-10 mm has been performed using a finite element method. Computation of a welded connection with due consideration of geometrical nonlinearity has been done in the paper. It has been shown that tensile of re-bars under load causes uneven stress distribution in a welded joint and their significant concentration is observed at crossing points from the welded joint to a base metal. An analysis of the obtained equivalent stresses at nodes and details of the welded joint structure has shown that they did not exceed permissible values for all diameters in case of the considered loading conditions. A comparison of stress values calculated has been carried out in accordance with the proposed method and experimentally obtained data. It has been revealed that application of tensile load (determined experimentally to the connection stress values at the connection and welded joint boundary reach an yield strength and subsequently it causes destruction of the connection. It has been established that the margin of safety for such type of connections is averagely equal from 30 to 60 %. The submitted calculated data are in full agreement with experimental data that proves correctness in selection of calculation schemes and loads.

  20. The Star Formation in Radio Survey: Jansky Very Large Array 33 GHz Observations of Nearby Galaxy Nuclei and Extranuclear Star-forming Regions

    Science.gov (United States)

    Murphy, E. J.; Dong, D.; Momjian, E.; Linden, S.; Kennicutt, R. C., Jr.; Meier, D. S.; Schinnerer, E.; Turner, J. L.

    2018-02-01

    We present 33 GHz imaging for 112 pointings toward galaxy nuclei and extranuclear star-forming regions at ≈2″ resolution using the Karl G. Jansky Very Large Array (VLA) as part of the Star Formation in Radio Survey. A comparison with 33 GHz Robert C. Byrd Green Bank Telescope single-dish observations indicates that the interferometric VLA observations recover 78% ± 4% of the total flux density over 25″ regions (≈kpc scales) among all fields. On these scales, the emission being resolved out is most likely diffuse non-thermal synchrotron emission. Consequently, on the ≈30–300 pc scales sampled by our VLA observations, the bulk of the 33 GHz emission is recovered and primarily powered by free–free emission from discrete H II regions, making it an excellent tracer of massive star formation. Of the 225 discrete regions used for aperture photometry, 162 are extranuclear (i.e., having galactocentric radii r G ≥ 250 pc) and detected at >3σ significance at 33 GHz and in Hα. Assuming a typical 33 GHz thermal fraction of 90%, the ratio of optically-thin 33 GHz to uncorrected Hα star formation rates indicates a median extinction value on ≈30–300 pc scales of A Hα ≈ 1.26 ± 0.09 mag, with an associated median absolute deviation of 0.87 mag. We find that 10% of these sources are “highly embedded” (i.e., A Hα ≳ 3.3 mag), suggesting that on average, H II regions remain embedded for ≲1 Myr. Finally, we find the median 33 GHz continuum-to-Hα line flux ratio to be statistically larger within r G < 250 pc relative to the outer disk regions by a factor of 1.82 ± 0.39, while the ratio of 33 GHz to 24 μm flux densities is lower by a factor of 0.45 ± 0.08, which may suggest increased extinction in the central regions.

  1. THE X-SHAPED BULGE OF THE MILKY WAY REVEALED BY WISE

    Energy Technology Data Exchange (ETDEWEB)

    Ness, Melissa [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Lang, Dustin, E-mail: ness@mpia-hd.mpg.de [Dunlap Institute and Department of Astronomy and Astrophysics, University of Toronto, 50 Saint George Street, Toronto, ON, M5S 3H4 (Canada)

    2016-07-01

    The Milky Way bulge has a boxy/peanut morphology and an X-shaped structure. This X-shape has been revealed by the “split in the red clump” from star counts along the line of sight toward the bulge, measured from photometric surveys. This boxy, X-shaped bulge morphology is not unique to the Milky Way and such bulges are observed in other barred spiral galaxies. N -body simulations show that boxy and X-shaped bulges are formed from the disk via dynamical instabilities. It has also been proposed that the Milky Way bulge is not X-shaped, but rather, the apparent split in the red clump stars is a consequence of different stellar populations, in an old classical spheroidal bulge. We present a Wide-Field Infrared Survey Explorer ( WISE ) image of the Milky Way bulge, produced by downsampling the publicly available “unWISE” coadds. The WISE image of the Milky Way bulge shows that the X-shaped nature of the Milky Way bulge is self-evident and irrefutable. The X-shape morphology of the bulge in itself and the fraction of bulge stars that comprise orbits within this structure has important implications for the formation history of the Milky Way, and, given the ubiquity of boxy X-shaped bulges, spiral galaxies in general.

  2. Thermal efficiency maximization for H- and X-shaped heat exchangers based on constructal theory

    International Nuclear Information System (INIS)

    Chen, Lingen; Feng, Huijun; Xie, Zhihui; Sun, Fengrui

    2015-01-01

    Constructal optimizations of H- and X-shaped heat exchangers are carried out by taking the maximum thermal efficiency (the ratio of the dimensionless heat transfer rate to the dimensionless total pumping power) as optimization objective. The constraints of total tube volumes and spaces occupied by heat exchangers are considered in the optimizations. For the H-shaped heat exchanger, the thermal efficiency decreases when the dimensionless mass flow rate increases. For the higher order of the X-shaped heat exchanger, when the order number is 3, the thermal efficiency of the heat exchanger with Murry law is increased by 68.54% than that with equal flow velocity in the tubes, and by 435.46% than that with equal cross section area of the tubes. - Highlights: • Constructal optimizations of H- and X-shaped heat exchangers are carried out. • Maximum thermal efficiency is taken as optimization objective. • Thermal efficiency is defined as ratio of heat transfer rate to total pumping power. • Optimal constructs of H- and X-shaped heat exchangers are obtained. • Thermal efficiency of X-shaped heat exchanger is larger than that of H-shaped.

  3. Earthquake Response of Reinforced Concrete Building Retrofitted with Geopolymer Concrete and X-shaped Metallic Damper

    Science.gov (United States)

    Madheswaran, C. K.; Prakash vel, J.; Sathishkumar, K.; Rao, G. V. Rama

    2017-06-01

    A three-storey half scale reinforced concrete (RC) building is fixed with X-shaped metallic damper at the ground floor level, is designed and fabricated to study its seismic response characteristics. Experimental studies are carried out using the (4 m × 4 m) tri-axial shake-table facility to evaluate the seismic response of a retrofitted RC building with open ground storey (OGS) structure using yielding type X-shaped metallic dampers (also called as Added Damping and Stiffness-ADAS elements) and repairing the damaged ground storey columns using geopolymer concrete composites. This elasto-plastic device is normally incorporated within the frame structure between adjacent floors through chevron bracing, so that they efficiently enhance the overall energy dissipation ability of the seismically deficient frame structure under earthquake loading. Free vibration tests on RC building without and with yielding type X-shaped metallic damper is carried out. The natural frequencies and mode shapes of RC building without and with yielding type X-shaped metallic damper are determined. The retrofitted reinforced concrete building is subjected to earthquake excitations and the response from the structure is recorded. This work discusses the preparation of test specimen, experimental set-up, instrumentation, method of testing of RC building and the response of the structure. The metallic damper reduces the time period of the structure and displacement demands on the OGS columns of the structure. Nonlinear time history analysis is performed using structural analysis package, SAP2000.

  4. The nearby supernova factory

    International Nuclear Information System (INIS)

    Wood-Vasey, W.M.; Aldering, G.; Lee, B.C.; Loken, S.; Nugent, P.; Perlmutter, S.; Siegrist, J.; Wang, L.; Antilogus, P.; Astier, P.; Hardin, D.; Pain, R.; Copin, Y.; Smadja, G.; Gangler, E.; Castera, A.; Adam, G.; Bacon, R.; Lemonnier, J.-P.; Pecontal, A.; Pecontal, E.; Kessler, R.

    2004-01-01

    The Nearby Supernova Factory (SNfactory) is an ambitious project to find and study in detail approximately 300 nearby Type Ia supernovae (SNe Ia) at redshifts 0.03 < z < 0.08. This program will provide an exceptional data set of well-studied SNe in the nearby smooth Hubble flow that can be used as calibration for the current and future programs designed to use SNe to measure the cosmological parameters. The first key ingredient for this program is a reliable supply of Hubble-flow SNe systematically discovered in unprecedented numbers using the same techniques as those used in distant SNe searches. In 2002, 35 SNe were found using our test-bed pipeline for automated SN search and discovery. The pipeline uses images from the asteroid search conducted by the Near Earth Asteroid Tracking group at JPL. Improvements in our subtraction techniques and analysis have allowed us to increase our effective SN discovery rate to ∼12 SNe/month in 2003

  5. Management of advanced hilar biliary malignancy with X-shaped stenting technique

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Gyu Hyuk; You, Jin Jong; Ahn, In Oak; Na, Jae Boem; Chung, Sugn Hoon [College of Medicine, Gyeongsang National University, Chinju (Korea, Republic of)

    2000-06-01

    To report X-shaped stent insertion and its result in the patients with advanced hilar malignancy. X-shaped stents were inserted in six patients with advanced hilar malignancy involving segmental branches of both intrahepatic bile ducts (IHD). The causes were cholangiocarcinomas in five patients and recurrent GB cancer in one. The procedure includes three steps: (1) the insertion of two wires through three IHDs in an X configuration, using a stone basket; (2) balloon dilatation of lesions, and (3) the insertion of two stents in an as X configuration. Stents were inserted after balloon dilatation in five patients, and without balloon dilatation in one. Changes in serum bilirubin levels and procedure-related problems were reviewed. In all patients, serum bilirubin levels gradually decreased, but in two, they increased again. One of these two died of sepsis after 1 month. There was bile leakage through the puncture and bile was extracted from malignant ascites. In the other patient, occlusion of the left stent tip occurred, and additional left PTBD was performed 3 months later. Hemobilia developed in all five patients with balloon dilatation, these all experienced pain during dilatation, but afterwards this disappeared. One stent without pre-balloon dilation showed incomplete self-expansion at the crossing part and supplementary balloon dilatations were performed. In patients with advanced hilar malignancy,X-shaped stent insertion is a new palliation. Problems such as hemobilia, pain, and intraperitoneal bile leakage may, however, occur. (author)

  6. Non-potential Field Formation in the X-shaped Quadrupole Magnetic Field Configuration

    Energy Technology Data Exchange (ETDEWEB)

    Kawabata, Y.; Shimizu, T. [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Inoue, S., E-mail: kawabata.yusuke@ac.jaxa.jp [Max-Planck-Institute for Solar System Research, Justus-von-Liebig-Weg 3 D-37077 Göttingen (Germany)

    2017-06-20

    Some types of solar flares are observed in X-shaped quadrupolar field configuration. To understand the magnetic energy storage in such a region, we studied non-potential field formation in an X-shaped quadrupolar field region formed in the active region NOAA 11967, which produced three X-shaped M-class flares on 2014 February 2. Nonlinear force-free field modeling was applied to a time series of vector magnetic field maps from the Solar Optical Telescope on board Hinode and the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory . Our analysis of the temporal three-dimensional magnetic field evolution shows that the sufficient free energy had already been stored more than 10 hr before the occurrence of the first M-class flare and that the storage was observed in a localized region. In this localized region, quasi-separatrix layers (QSLs) started to develop gradually from 9 hr before the first M-class flare. One of the flare ribbons that appeared in the first M-class flare was co-spatial with the location of the QSLs, suggesting that the formation of the QSLs is important in the process of energy release. These QSLs do not appear in the potential field calculation, indicating that they were created by the non-potential field. The formation of the QSLs was associated with the transverse photospheric motion of the pre-emerged flux and the emergence of a new flux. This observation indicates that the occurrence of the flares requires the formation of QSLs in the non-potential field in which free magnetic energy is stored in advance.

  7. Disturbance Ecology from nearby Supernovae

    OpenAIRE

    Hartmann, D. H.; Kretschmer, K.; Diehl, R.

    2002-01-01

    Monte Carlo simulations of Galactic Supernovae are carried out to study the rate of nearby events, which may have a direct effect on Earth's ecology though ionizing radiation and cosmic ray bombardment. A nearby supernova may have left a radioactive imprint (60Fe) in recent galactic history.

  8. 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

  9. Scanning of electron beam by X-shaped trajectory as a means of root weld defect minimizing in EBW

    International Nuclear Information System (INIS)

    Belen'kij, V.Ya.

    1986-01-01

    The application of X-shaped electron beam scanning for welding to eliminate peak-formation and accompanying root weld defects. It is shown that the use of X-shaped scanning allows one to attain substantial decrease of root penetration peaks amplitude with a slight decrease of its depth. It is advisable to perform welding with optimum electron beam focusing which can be established by maximum value of oscillations amplitude of the alternating-current spectrum component in the circuit of the welded product or collector with frequency in the 3-15 kHz range with motionless as well as oscillating beam

  10. Nuclear activity in nearby galaxies

    NARCIS (Netherlands)

    Filho, Mercedes Esteves

    2003-01-01

    The main focus of this thesis has been the search for and study of low luminosity AGN. We have detected severa low luminosity AGN in nearby galaxies, revealing that this type of activity can occur in a broad range of galaxy types and powers. Furthermore, we have been able to establish importan

  11. Merger origin of radio galaxies investigated with HI observations

    NARCIS (Netherlands)

    Emonts, BHC; Morganti, R; Oosterloo, TA; van der Hulst, JM; Tadhunter, CN; van Moorsel, G; Holt, J

    2006-01-01

    We present results of an H I study of a complete sample of nearby radio galaxies. Our goal is to investigate whether merger or interaction events could be at the origin of the radio-AGN activity. Around five of our radio galaxies, hosted mainly by early-type galaxies, we detect extended H I in

  12. 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.

  13. Reconstruction of a Large-scale Pre-flare Coronal Current Sheet Associated with a Homologous X-shaped Flare

    Science.gov (United States)

    Jiang, Chaowei; Yan, Xiaoli; Feng, Xueshang; Duan, Aiying; Hu, Qiang; Zuo, Pingbing; Wang, Yi

    2017-11-01

    As a fundamental magnetic structure in the solar corona, electric current sheets (CSs) can form either prior to or during a solar flare, and they are essential for magnetic energy dissipation in the solar corona because they enable magnetic reconnection. However, the static reconstruction of a CS is rare, possibly due to limitations that are inherent in the available coronal field extrapolation codes. Here we present the reconstruction of a large-scale pre-flare CS in solar active region 11967 using an MHD-relaxation model constrained by the SDO/HMI vector magnetogram. The CS is associated with a set of peculiar homologous flares that exhibit unique X-shaped ribbons and loops occurring in a quadrupolar magnetic configuration.This is evidenced by an ’X’ shape, formed from the field lines traced from the CS to the photosphere. This nearly reproduces the shape of the observed flare ribbons, suggesting that the flare is a product of the dissipation of the CS via reconnection. The CS forms in a hyperbolic flux tube, which is an intersection of two quasi-separatrix layers. The recurrence of the X-shaped flares might be attributed to the repetitive formation and dissipation of the CS, as driven by the photospheric footpoint motions. These results demonstrate the power of a data-constrained MHD model in reproducing a CS in the corona as well as providing insight into the magnetic mechanism of solar flares.

  14. RADIO CINEMA

    OpenAIRE

    JØRGENSEN, MARIA; HALADYN, DENNIS; DIENER, BIRK; REESE, LIV LINDTNER

    2016-01-01

    First article: Radio Cinema has become more and more popular in Copenhagen - escalating since the first Radio Cinema event was held in 2013. Now, it is monthly taking place in Gloria Biograf. The audience meets in the darkened cinema auditory and listens to a curated program of podcasts. In this article we investigate how the experience of participating in a Radio Cinema event feels through the theory of Sarah Pink’s Doing Sensory Ethnography (2009). In the first par...

  15. A Proof-of-concept Demonstrator for Cognitive Radio

    NARCIS (Netherlands)

    Heskamp, M.; Hoeksema, F.W.; Schiphorst, Roelof; Slump, Cornelis H.

    2005-01-01

    The Adaptive Ad-hoc Free Band Wireless Communications (AAF) project is researching the possibility of using Software Defined Radio for wireless networks that needs to operate in an unknown or even hostile radio environment. Each node in the network needs to be cognitive of nearby transceivers in

  16. Spectrum monitoring: Radio Frequency Interferences (RFI) profile for ...

    African Journals Online (AJOL)

    It was crucial to monitor the Radio Frequency Interference (RFI) in order to conduct the radio astronomical research with very minimum RFI. These RFI will be distorted the astronomical data. In this work, we have investigated the RFI strength (dBm) and presenting on how the nearby RFI affect to the OH lines window (1600 ...

  17. Satellite Radio

    Indian Academy of Sciences (India)

    Satellites have been a highly effective platform for multi- form broadcasts. This has led to a revival of the radio era. The satellite radio is a natural choice to bridge the digital gap. It has several novel features like selective addressing and error control. The value-added services from such systems are of particular interest.

  18. Merger-origin of radio galaxies investigated with H I observation

    NARCIS (Netherlands)

    Emonts, B.H.C.; Morganti, R.; Oosterloo, T.; Hulst, J.M. van der; Tadhunter, C.N.; Moorsel, G. van; Holt, J.; hOLT, j.

    2005-01-01

    Abstract: We present results of an HI study of a complete sample of nearby radio galaxies. Our goal is to investigate whether merger or interaction events could be at the origin of the radio-AGN activity. Around five of our radio galaxies, hosted mainly by early-type galaxies, we detect extended HI

  19. Coordinating Actions in Nearby 3-D Space

    National Research Council Canada - National Science Library

    Steinman, Robert

    2001-01-01

    .... The answer to this (and derivative) questions was not known because, until recently, binocular gaze-errors could not be measured accurately when nearby objects were handled by a subject free to move naturally...

  20. Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Kapińska, A. D.; Staveley-Smith, L.; Meurer, G. R.; For, B.-Q. [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Hwy, WA 6009 (Australia); Crocker, R. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Bhandari, S.; Callingham, J. R.; Gaensler, B. M.; Hancock, P. J.; Lenc, E. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), Sydney NSW (Australia); Hurley-Walker, N.; Seymour, N. [International Centre for Radio Astronomy Research (ICRAR), Curtin University, Bentley, WA 6102 (Australia); Offringa, A. R. [Netherlands Institute for Radio Astronomy (ASTRON), P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Hanish, D. J. [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Ekers, R. D.; Bell, M. E. [CSIRO Astronomy and Space Science (CASS), P.O. Box 76, Epping, NSW 1710 (Australia); Dwarakanath, K. S. [Raman Research Institute, Bangalore 560080 (India); Hindson, L. [Centre of Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140 (New Zealand); McKinley, B., E-mail: anna.kapinska@uwa.edu.au [School of Physics, The University of Melbourne, Parkville, VIC 3010 (Australia); and others

    2017-03-20

    We present new radio continuum observations of NGC 253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC 253 between 76 MHz and 11 GHz. The spectrum is best described as a sum of a central starburst and extended emission. The central component, corresponding to the inner 500 pc of the starburst region of the galaxy, is best modeled as an internally free–free absorbed synchrotron plasma, with a turnover frequency around 230 MHz. The extended emission component of the spectrum of NGC 253 is best described as a synchrotron emission flattening at low radio frequencies. We find that 34% of the extended emission (outside the central starburst region) at 1 GHz becomes partially absorbed at low radio frequencies. Most of this flattening occurs in the western region of the southeast halo, and may be indicative of synchrotron self-absorption of shock-reaccelerated electrons or an intrinsic low-energy cutoff of the electron distribution. Furthermore, we detect the large-scale synchrotron radio halo of NGC 253 in our radio images. At 154–231 MHz the halo displays the well known X-shaped/horn-like structure, and extends out to ∼8 kpc in the z -direction (from the major axis).

  1. X-Shaped ZIF-8 for Immobilization Rhizomucor miehei Lipase via Encapsulation and Its Application toward Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Miaad Adnan

    2018-02-01

    Full Text Available This study presents a one-step encapsulation method for synthesizing X-shaped zeolitic imidazolate frameworks (ZIF-8 and immobilizing Rhizomucor miehei lipase (RML. We proved that the morphological structure of ZIF-8 had changed after immobilization with enhanced characterization using a field-emission scanning electron microscope, an energy-dispersive spectrometer, a transmission electron microscope, a Fourier transform infrared spectrometer, and powder X-ray diffraction. The surface area and pore size of the carrier were investigated before and after immobilization using Brunauer–Emmett–Teller and Barrett–Joyner–Halenda methods, respectively. RML@ZIF-8 exhibited high recovery activity of up to 2632%, representing a 26-fold increase in its free lipase. Encapsulated RML was used for biodiesel production from soybean oil in an isooctane system with a conversion yield of 95.6% under optimum conditions. The resulting reusability of the immobilized enzyme indicated no substantial decline in the conversion yield, which remained at 84.7% of the initial activity after 10 cycles. The stability and high performance of the immobilized enzyme are attributed to the harmony between RML and ZIF-8 based on the easy synthesis of ZIF-8 and the short time required to immobilize RML.

  2. 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...

  3. A Comparison of Independent Star Formation Diagnostics for a UV-Selected Sample of Nearby Galaxies

    OpenAIRE

    Sullivan, Mark; Mobasher, Bahram; Chan, Ben; Cram, Lawrence; Ellis, Richard; Treyer, Marie; Hopkins, Andrew

    2001-01-01

    We present results from a decimetric radio survey undertaken with the Very Large Array as part of a longer term goal to inter-compare star formation and dust extinction diagnostics, on a galaxy by galaxy basis, for a representative sample of nearby galaxies. For our survey field, Selected Area 57, star formation rates derived from 1.4GHz luminosities are compared with earlier nebular emission line and ultraviolet (UV) continuum diagnostics. We find broad correlations, over several decades in ...

  4. 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.

  5. Radio astronomy

    International Nuclear Information System (INIS)

    Parijskij, Y.N.; Gossachinskij, I.V.; Zuckerman, B.; Khersonsky, V.K.; Pustilnik, S.; Robinson, B.J.

    1976-01-01

    A critical review of major developments and discoveries in the field of radioastronomy during the period 1973-1975 is presented. The report is presented under the following headings:(1) Continuum radiation from the Galaxy; (2) Neutral hydrogen, 21 cm (galactic and extragalactic) and recombination lines; (3) Radioastronomy investigations of interstellar molecules; (4) Extragalactic radio astronomy and (6) Development in radio astronomy instruments. (B.R.H.)

  6. Radio Source Morphology: 'nature or nuture'?

    Science.gov (United States)

    Banfield, Julie; Emonts, Bjorn; O'Sullivan, Shane

    2012-10-01

    Radio sources, emanating from supermassive black-holes in the centres of active galaxies, display a large variety of morphological properties. It is a long-standing debate to what extent the differences between various types of radio sources are due to intrinsic properties of the central engine (`nature') or due to the properties of the interstellar medium that surrounds the central engine and host galaxy (`nurture'). Settling this `nature vs. nurture' debate for nearby radio galaxies, which can be studied in great detail, is vital for understanding the properties and evolution of radio galaxies throughout the Universe. We propose to observe the radio galaxy NGC 612 where previous observations have detected the presence of a large-scale HI bridge between the host galaxy and a nearby galaxy NGC 619. We request a total of 13 hrs in the 750m array-configuration to determine whether or not the 100 kpc-scale radio source morphology is directly related to the intergalactic distribution of neutral hydrogen gas.

  7. 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

  8. The polarization of radio galaxies

    International Nuclear Information System (INIS)

    Jaegers, W.J.

    1986-01-01

    In this thesis radio observations at 0.6 GHz together with matched (convolved) observations at 1.4 GHz of 30 radiosources are described and interpreted. Sources of great interest which are individually discussed are the complex nearby source 3C66B, the source 4C73.48, the narrow edge-darkened double source 3C130 (together with two newly observed narrow-edge-darkened doubles), the galaxies 3C129 and 3C390.3 and the giant quasar 4C34.47. (Auth.)

  9. The ISM in nearby galaxies: NGC1365

    NARCIS (Netherlands)

    Baan, Willem; Loenen, Edo; Spaans, Marco

    We propose a sensitive spectral survey of the nuclear region of the nearby Luminous Infrared Galaxy NGC1365. These observations are to confirm a similar program carried out in 2007, which suffers from severe bandpass issues. The previous observations have resulted in 76+ tentative detections,

  10. Spectrophotometry of nearby field galaxies : The data

    NARCIS (Netherlands)

    Jansen, RA; Fabricant, D; Franx, M; Caldwell, N

    We have obtained integrated and nuclear spectra as well as U, B, R surface photometry for a representative sample of 196 nearby galaxies. These galaxies span the entire Hubble sequence in morphological type, as well as a wide range of luminosities (M(B) = -14 to -22). Here we present the

  11. Nobeyama CO Atlas of Nearby Spiral Galaxies

    Science.gov (United States)

    Kuno, N.; Nakai, N.; Sorai, K.; Sato, N..; Yamauchi, A.; Tosaki, T.; Shioya, Y.; Vila-Vilaró, B.; Nishiyama, K.; Ishihara, Y.; Cepa, J.

    BEARS is a 25-beam focal plane array receiver mounted on the Nobeyama 45-m telescope. The combination of the large dish size of the telescope with the excellent performance of this receiver makes it an ideal tool for mapping observations of extended regions of the sky. We present here one of its current applications in a CO mapping survey of nearby spiral galaxies.

  12. Important Nearby Galaxies without Accurate Distances

    Science.gov (United States)

    McQuinn, Kristen

    2014-10-01

    The Spitzer Infrared Nearby Galaxies Survey (SINGS) and its offspring programs (e.g., THINGS, HERACLES, KINGFISH) have resulted in a fundamental change in our view of star formation and the ISM in galaxies, and together they represent the most complete multi-wavelength data set yet assembled for a large sample of nearby galaxies. These great investments of observing time have been dedicated to the goal of understanding the interstellar medium, the star formation process, and, more generally, galactic evolution at the present epoch. Nearby galaxies provide the basis for which we interpret the distant universe, and the SINGS sample represents the best studied nearby galaxies.Accurate distances are fundamental to interpreting observations of galaxies. Surprisingly, many of the SINGS spiral galaxies have numerous distance estimates resulting in confusion. We can rectify this situation for 8 of the SINGS spiral galaxies within 10 Mpc at a very low cost through measurements of the tip of the red giant branch. The proposed observations will provide an accuracy of better than 0.1 in distance modulus. Our sample includes such well known galaxies as M51 (the Whirlpool), M63 (the Sunflower), M104 (the Sombrero), and M74 (the archetypal grand design spiral).We are also proposing coordinated parallel WFC3 UV observations of the central regions of the galaxies, rich with high-mass UV-bright stars. As a secondary science goal we will compare the resolved UV stellar populations with integrated UV emission measurements used in calibrating star formation rates. Our observations will complement the growing HST UV atlas of high resolution images of nearby galaxies.

  13. Satellite Radio

    Indian Academy of Sciences (India)

    communications as well as for point-to-multipoint broadcasting. GENERAL I ARTICLE. Radio is perceived to be an individual's possession because of its portability. It can be ... (See Box 1.) Gsa satellites are used for point-to-point communications as ... digital modulations one uses perceptual coding using auditory masking.

  14. Nearby Exo-Earth Astrometric Telescope (NEAT)

    Science.gov (United States)

    Shao, M.; Nemati, B.; Zhai, C.; Goullioud, R.

    2011-01-01

    NEAT (Nearby Exo ]Earths Astrometric Telescope) is a modest sized (1m diameter telescope) It will be capable of searching approx 100 nearby stars down to 1 Mearth planets in the habitable zone, and 200 @ 5 Mearth, 1AU. The concept addresses the major issues for ultra -precise astrometry: (1) Photon noise (0.5 deg dia field of view) (2) Optical errors (beam walk) with long focal length telescope (3) Focal plane errors , with laser metrology of the focal plane (4) PSF centroiding errors with measurement of the "True" PSF instead of using a "guess " of the true PSF, and correction for intra pixel QE non-uniformities. Technology "close" to complete. Focal plane geometry to 2e-5 pixels and centroiding to approx 4e -5 pixels.

  15. THE GALEX NEARBY YOUNG-STAR SURVEY

    International Nuclear Information System (INIS)

    Rodriguez, David R.; Faherty, Jacqueline K.; Zuckerman, B.; Kastner, Joel H.; Bessell, M. S.; Murphy, Simon J.

    2013-01-01

    We describe a method that exploits data from the Galaxy Evolution Explorer (GALEX) ultraviolet and Wide-field Infrared Survey Explorer and Two Micron All Sky Survey infrared source catalogs, combined with proper motions and empirical pre-main sequence isochrones, to identify candidate nearby, young, low-mass stars. Applying our method across the full GALEX-covered sky, we identify 2031 mostly M-type stars that, for an assumed age of 10 (100) Myr, all lie within ∼150 (∼90) pc of Earth. The distribution of M spectral subclasses among these ∼2000 candidate young stars peaks sharply in the range M3-M4; these subtypes constitute 50% of the sample, consistent with studies of the M star population in the immediate solar neighborhood. We focus on a subset of 58 of these candidate young M stars in the vicinity of the Tucana-Horologium association. Only 20 of these 58 candidates were detected in the ROSAT All-Sky X-ray Survey—reflecting the greater sensitivity of GALEX for the purposes of identifying active nearby, young stars, particularly for stars of type M4 and later. Based on statistical analysis of the kinematics and/or spectroscopic followup of these 58 M stars, we find that 50% (29 stars) indeed have properties consistent with Tuc-Hor membership, while 12 are potential new members of the Columba association, and 2 may be AB Dor moving group members. Hence, ∼75% of our initial subsample of 58 candidates are likely members of young (age ∼ 10-40 Myr) stellar moving groups within 100 pc, verifying that the stellar color- and kinematics-based selection algorithms described here can be used to efficiently isolate nearby, young, low-mass objects from among the field star population. Future studies will focus on characterizing additional subsamples selected from among this list of candidate nearby, young M stars

  16. Star Formation Histories of Nearby Dwarf Galaxies

    OpenAIRE

    Grebel, Eva K.

    2000-01-01

    Properties of nearby dwarf galaxies are briefly discussed. Dwarf galaxies vary widely in their star formation histories, the ages of their subpopulations, and in their enrichment history. Furthermore, many dwarf galaxies show evidence for spatial variations in their star formation history; often in the form of very extended old populations and radial gradients in age and metallicity. Determining factors in dwarf galaxy evolution appear to be both galaxy mass and environment. We may be observi...

  17. Stellar Death in the Nearby Universe

    Science.gov (United States)

    Holoien, Thomas Warren-Son

    The night sky is replete with transient and variable events that help shape our universe. The violent, explosive deaths of stars represent some of the most energetic of these events, as a single star is able to outshine billions during its final moments. Aside from imparting significant energy into their host environments, stellar deaths are also responsible for seeding heavy elements into the universe, regulating star formation in their host galaxies, and affecting the evolution of supermassive black holes at the centers of their host galaxies. The large amount of energy output during these events allows them to be seen from billions of lightyears away, making them useful observational probes of physical processes important to many fields of astronomy. In this dissertation I present a series of observational studies of two classes of transients associated with the deaths of stars in the nearby universe: tidal disruption events (TDEs) and supernovae (SNe). Discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN), the objects I discuss were all bright and nearby, and were subject to extensive follow-up observational campaigns. In the first three studies, I present observational data and theoretical models of ASASSN-14ae, ASASSN-14li, and ASASSN-15oi, three TDEs discovered by ASAS-SN and three of the most well-studied TDEs ever discovered. Next I present the discovery of ASASSN-13co, an SN that does not conform to the traditional model of Type II SNe. Finally, I discuss the full sample of bright SNe discovered from 2014 May 1 through 2016 December 31, which is significantly less biased than previous nearby SN samples due to the ASAS-SN survey approach, and perform statistical analyses on this population that will be used for future studies of nearby SNe and their hosts.

  18. Sunspot Light Walls Suppressed by Nearby Brightenings

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shuhong; Zhang, Jun; Hou, Yijun; Li, Xiaohong [CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Erdélyi, Robertus [Solar Physics and Space Plasma Research Centre, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Yan, Limei, E-mail: shuhongyang@nao.cas.cn [Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 (China)

    2017-07-01

    Light walls, as ensembles of oscillating bright structures rooted in sunspot light bridges, have not been well studied, although they are important for understanding sunspot properties. Using the Interface Region Imaging Spectrograph and Solar Dynamics Observatory observations, here we study the evolution of two oscillating light walls each within its own active region (AR). The emission of each light wall decays greatly after the appearance of adjacent brightenings. For the first light wall, rooted within AR 12565, the average height, amplitude, and oscillation period significantly decrease from 3.5 Mm, 1.7 Mm, and 8.5 minutes to 1.6 Mm, 0.4 Mm, and 3.0 minutes, respectively. For the second light wall, rooted within AR 12597, the mean height, amplitude, and oscillation period of the light wall decrease from 2.1 Mm, 0.5 Mm, and 3.0 minutes to 1.5 Mm, 0.2 Mm, and 2.1 minutes, respectively. Particularly, a part of the second light wall even becomes invisible after the influence of a nearby brightening. These results reveal that the light walls are suppressed by nearby brightenings. Considering the complex magnetic topology in light bridges, we conjecture that the fading of light walls may be caused by a drop in the magnetic pressure, where the flux is canceled by magnetic reconnection at the site of the nearby brightening. Another hypothesis is that the wall fading is due to the suppression of driver source ( p -mode oscillation), resulting from the nearby avalanche of downward particles along reconnected brightening loops.

  19. 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.

  20. The Hunt for Nearby White Dwarfs

    Science.gov (United States)

    Subasavage, John P., Jr.; Bergeron, P.; Henry, T. J.; Dufour, P.; Hambly, N. C.; Beaulieu, T. D.; RECONS

    2006-12-01

    White Dwarfs (WDs) serve as test beds to probe into astrophysically interesting questions such as (1) the ages of star clusters and Galactic components (i.e. disk, halo), (2) Galactic evolution, (3) halo dark matter constituents, (4) stellar structure theory, and (5) stellar evolution theory. The nearby WD population provides the brightest and most easily studied representatives. How confident are we that all of the nearest WDs have been identified? In an effort to answer this question, we have begun an initiative to identify and characterize new nearby WDs, particularly in the southern hemisphere. We identify new WDs using medium resolution (R 1000) optical spectroscopy, and estimate physical parameters and distances using optical photometry combined with 2MASS near-infrared photometry. For objects within 25 pc (Catalogue of Nearby Stars, and NStars Database horizons), we determine a trigonometric parallax via CTIOPI (Cerro Tololo Inter-American Observatory Parallax Investigation). Of the 43 new WD systems discovered so far, 21 are likely within 25 pc, a volume that contains 107 WDs with trigonometric parallaxes. A spectroscopic observing run in December will likely increase these values. Interesting objects include two that are likely double degenerates including one with a magnetic component, one that is a cool (T$_{eff}$ 5000 K) likely mixed atmosphere WD with deficient flux at near-infrared wavelengths, and three that are metal-rich. Observations are underway via the Hubble Space Telescope to resolve four potential double degenerates (the new magnetic WD and three other previously known WDs) for dynamical mass determinations. All ground-based observations are obtained as part of the SMARTS (Small and Moderate Aperture Research Telescope System) Consortium at CTIO. We wish to thank NASA's Space Interferometry Mission, the National Science Foundation, the Space Telescope Science Institute, and GSU for their continued support.

  1. Suites of dwarfs around Nearby giant galaxies

    International Nuclear Information System (INIS)

    Karachentsev, Igor D.; Kaisina, Elena I.; Makarov, Dmitry I.

    2014-01-01

    The Updated Nearby Galaxy Catalog (UNGC) contains the most comprehensive summary of distances, radial velocities, and luminosities for 800 galaxies located within 11 Mpc from us. The high density of observables in the UNGC makes this sample indispensable for checking results of N-body simulations of cosmic structures on a ∼1 Mpc scale. The environment of each galaxy in the UNGC was characterized by a tidal index Θ 1 , depending on the separation and mass of the galaxy's main disturber (MD). We grouped UNGC galaxies with a common MD in suites, and ranked suite members according to their Θ 1 . All suite members with positive Θ 1 are assumed to be physical companions of the MD. About 58% of the sample are members of physical groups. The distribution of suites by the number of members, n, follows a relation N(n) ∼ n –2 . The 20 most populated suites contain 468 galaxies, i.e., 59% of the UNGC sample. The fraction of MDs among the brightest galaxies is almost 100% and drops to 50% at M B = –18 m . We discuss various properties of MDs, as well as galaxies belonging to their suites. The suite abundance practically does not depend on the morphological type, linear diameter, or hydrogen mass of the MD, the tightest correlation being with the MD dynamical mass. Dwarf galaxies around MDs exhibit well-known segregation effects: the population of the outskirts has later morphological types, richer H I contents, and higher rates of star formation activity. Nevertheless, there are some intriguing cases where dwarf spheroidal galaxies occur at the far periphery of the suites, as well as some late-type dwarfs residing close to MDs. Comparing simulation results with galaxy groups, most studies assume the Local Group is fairly typical. However, we recognize that the nearby groups significantly differ from each other and there is considerable variation in their properties. The suites of companions around the Milky Way and M31, consisting of the Local Group, do not

  2. Cold gas & mergers: fundamental difference in HI properties of different types of radio galaxies?

    NARCIS (Netherlands)

    Emonts, Bjorn; Morganti, Raffaella; Oosterloo, Tom; van Gorkom, Jacqueline

    2008-01-01

    We present results of a study of large-scale neutral hydrogen (HI) gas in nearby radio galaxies. We find that the early-type host galaxies of different types of radio sources (compact, FR-I and FR-II) appear to contain fundamentally different large-scale HI properties: enormous regular rotating

  3. Fast outflow of Hi in starburst radio galaxy 3C 293

    NARCIS (Netherlands)

    Emonts, B; van der Hulst, T; Morganti, R; Oosterloo, T; Tadhunter, C; Holt, J; Wills, K; Aalto, S; Huttemeister, S; Pedlar, A

    2004-01-01

    We detect a fast outflow of gas in the central region of the nearby starburst radio galaxy 3C 293. The outflow is detected both in the optical emission lines of ionized gas as well as in HI absorption against the radio continuum. The broad HI absorption feature (observed with the recently upgraded

  4. State-of-the-art multi-wavelength observations of nearby brightest group/cluster galaxies

    Science.gov (United States)

    Gendron-Marsolais, Marie-Lou; Hlavacek-Larrondo, Julie

    2018-01-01

    Nearby galaxy groups and clusters are crucial to our understanding of the impact of nuclear outbursts on the intracluster medium as their proximity allows us to study in detail the processes of feedback from active galactic nuclei in these systems. In this talk, I will present state-of-the-art multi-wavelength observations signatures of this mechanism.I will first show results on multi-configuration 230-470 MHz observations of the Perseus cluster from the Karl G. Jansky Very Large Array, probing the non-thermal emission from the old particle population of the AGN outflows. These observations reveal a multitude of new structures associated with the “mini-halo” and illustrate the high-quality images that can be obtained with the new JVLA at low radio-frequencies.Second, I will present new observations with the optical imaging Fourier transform spectrometer SITELLE (CFHT) of NGC 1275, the Perseus cluster's brightest galaxy. With its wide field of view, it is the only integral field unit spectroscopy instrument able to cover the large emission-line filamentary nebula in NGC 1275. I will present the first detailed velocity map of this nebula in its entirety and tackle the question of its origin (residual cooling flow or dragged gas).Finally, I will present deep Chandra observations of the nearby early-type massive elliptical galaxy NGC 4472, the most optically luminous galaxy in the local Universe, lying on the outskirts of the Virgo cluster. Enhanced X-ray rims around the radio lobes are detected and interpreted as gas uplifted from the core by the buoyant rise of the radio bubbles. We estimate the energy required to lift the gas to constitute a significant fraction of the total outburst energy.I will thus show how these high-fidelity observations of nearby brightest group/cluster galaxies are improving our understanding of the AGN feedback mechanism taking place in galaxy groups and clusters.

  5. Radio Jove: Jupiter Radio Astronomy for Citizens

    Science.gov (United States)

    Higgins, Charles; Thieman, J. R.; Flagg, R.; Reyes, F. J.; Sky, J.; Greenman, W.; Brown, J.; Typinski, D.; Ashcraft, T.; Mount, A.

    2014-01-01

    Radio JOVE is a hands-on educational activity that brings the radio sounds of the Sun, Jupiter, the Milky Way Galaxy, and terrestrial radio noise to students, teachers, and the general public. Participants may build a simple radio telescope kit, make scientific observations, and interact with professional radio observatories in real-time over the Internet. Our website (http://radiojove.gsfc.nasa.gov) includes science information, construction manuals, observing guides, and education resources for teachers and students. Radio Jove is continually expanding its participants with over 1800 kits sold to more than 70 countries worldwide. Recently some of our most dedicated observers have upgraded their Radio Jove antennas to semi-professional observatories. We have spectrographs and wide band antennas, some with 8 MHz bandwidth and some with dual polarization capabilities. In an effort to add to the science literature, these observers are coordinating their efforts to pursue some basic questions about Jupiter’s radio emissions (radio source locations, spectral structure, long term changes, etc.). We can compare signal and ionosphere variations using the many Radio Jove observers at different locations. Observers are also working with members of the Long Wavelength Array Station 1 (LWA1) radio telescope to coordinate observations of Jupiter; Radio Jove is planning to make coordinated observations while the Juno Mission is active beginning in 2015. The Radio Jove program is overviewed, its hardware and software are highlighted, recent sample observations are shown, and we demonstrate that we are capable of real citizen science.

  6. Nearby Hot Stars May Change Our View of Distant Sources

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    As if it werent enough that quasars distant and bright nuclei of galaxies twinkle of their own accord due to internal processes, nature also provides another complication: these distant radio sources can also appear to twinkle because of intervening material between them and us. A new study has identified a possible source for the material getting in the way.Unexplained VariabilityA Spitzer infrared view of the Helix nebula, which contains ionized streamers of gas extending radially outward from the central star. [NASA/JPL-Caltech/Univ. of Ariz.]Distant quasars occasionally display extreme scintillation, twinkling with variability timescales shorter than a day. This intra-day variability is much greater than we can account for with standard models of the interstellar medium lying between the quasar and us. So what could cause this extreme scattering instead?The first clue to this mystery came from the discovery of strong variability in the radio source PKS 1322110. In setting up follow-up observations of this object, Mark Walker (Manly Astrophysics, Australia) and collaborators noticed that, in the plane of the sky, PKS 1322110 lies very near the bright star Spica. Could this be coincidence, or might this bright foreground star have something to do with the extreme scattering observed?Diagram explaining the source of the intra-day radio source variability as intervening filaments surrounding a hot star. [M. Walker/CSIRO/Manly Astrophysics]Swarms of ClumpsWalker and collaborators put forward a hypothesis: perhaps the ultraviolet photons of nearby hot stars ionize plasma around them, which in turn causes the extreme scattering of the distant background sources.As a model, the authors consider the Helix Nebula, in which a hot, evolved star is surrounded by cool globules of molecular hydrogen gas. The radiation from the star hits these molecular clumps, dragging them into long radial streamers and ionizing their outer skins.Though the molecular clumps in the Helix

  7. Classical radio source propagating into outer HI disc in NGC 3801

    NARCIS (Netherlands)

    Emonts, B. H. C.; Burnett, C.; Morganti, R.; Struve, C.

    We present observations of a large-scale disc of neutral hydrogen (H I) in the nearby Fanaroff-Riley type I (FR I) radio galaxy NGC 3801 with the Westerbork Synthesis Radio Telescope. The HI disc (34 kpc in diameter and with M-HI = 1.3 x 10(9)M(circle dot)) is aligned with the radio jet axis. This

  8. Nearby outdoor environments and seniors physical activities

    Directory of Open Access Journals (Sweden)

    Zhe Wang

    2014-09-01

    Full Text Available More than 60% of older Americans have sedentary lifestyles1 1 According to DHHS (1996. and are recommended more physical activities for health benefit. Nearby outdoor environments on residential sites may impact older inhabitants׳ physical activities there (defined as walking, gardening, yard work, and other outdoor physical activities on residential sites. This study surveyed 110 assisted-living residents in Houston, Texas, regarding their previous residential sites before moving to a retirement community and physical activities there. Twelve environmental features were studied under four categories (typology, motivators, function, and safety. Based on data availability, a subset of 57 sample sites was analyzed in Geographic Information Systems. Hierarchical linear modeling was applied to estimate physical activities as a function of the environments. Higher levels of physical activity were found to be positively related with four environmental features (transitional-areas, connecting-paths, walk-ability, and less paving.

  9. WINGS: WFIRST Infrared Nearby Galaxy Survey

    Science.gov (United States)

    Williams, Benjamin

    WFIRST's combination of wide field and high resolution will revolutionize the study of nearby galaxies. We propose to produce and analyze simulated WFIRST data of nearby galaxies and their halos to maximize the scientific yield in the limited observing time available, ensuring the legacy value of WFIRST's eventual archive. We will model both halo structure and resolved stellar populations to optimize WFIRST's constraints on both dark matter and galaxy formation models in the local universe. WFIRST can map galaxy structure down to ~35 mag/square arcsecond using individual stars. The resulting maps of stellar halos and accreting dwarf companions will provide stringent tests of galaxy formation and dark matter models on galactic (and even sub-galactic) scales, which is where the most theoretical tension exists with the Lambda-CDM model. With a careful, coordinated plan, WFIRST can be expected to improve current sample sizes by 2 orders of magnitude, down to surface brightness limits comparable to those currently reached only in the Local Group, and that are >4 magnitudes fainter than achievable from the ground due to limitations in star-galaxy separation. WFIRST's maps of galaxy halos will simultaneously produce photometry for billions of stars in the main bodies of galaxies within 10 Mpc. These data will transform studies of star formation histories that track stellar mass growth as a function of time and position within a galaxy. They also will constrain critical stellar evolution models of the near-infrared bright, rapidly evolving stars that can contribute significantly to the integrated light of galaxies in the near-infrared. Thus, with WFIRST we can derive the detailed evolution of individual galaxies, reconstruct the complete history of star formation in the nearby universe, and put crucial constraints on the theoretical models used to interpret near-infrared extragalactic observations. We propose a three-component work plan that will ensure these gains by

  10. Galaxy Clustering Around Nearby Luminous Quasars

    Science.gov (United States)

    Fisher, Karl B.; Bahcall, John N.; Kirhakos, Sofia; Schneider, Donald P.

    1996-01-01

    We examine the clustering of galaxies around a sample of 20 luminous low redshift (z approx. less than 0.30) quasars observed with the Wide Field Camera-2 on the Hubble Space Telescope (HST). The HST resolution makes possible galaxy identification brighter than V = 24.5 and as close as 1 min or 2 min to the quasar. We find a significant enhancement of galaxies within a projected separation of approx. less than 100 1/h kpc of the quasars. If we model the QSO/galaxy correlation function as a power law with a slope given by the galaxy/galaxy correlation function, we find that the ratio of the QSO/galaxy to galaxy/galaxy correlation functions is 3.8 +/- 0.8. The galaxy counts within r less than 15 1/h kpc of the quasars are too high for the density profile to have an appreciable core radius (approx. greater than 100 1/h kpc). Our results reinforce the idea that low redshift quasars are located preferentially in groups of 10-20 galaxies rather than in rich clusters. We see no significant difference in the clustering amplitudes derived from radio-loud and radio-quiet subsamples.

  11. Large-scale HI in nearby radio galaxies : II. The nature of classical low-power radio sources

    NARCIS (Netherlands)

    Emonts, B. H. C.; Morganti, R.; Struve, C.; Oosterloo, T. A.; van Moorsel, G.; Tadhunter, C. N.; van der Hulst, J. M.; Brogt, E.; Holt, J.; Mirabal, N.

    An important aspect of solving the long-standing question as to what triggers various types of active galactic nuclei (AGN) involves a thorough understanding of the overall properties and formation history

  12. Updated 34-band Photometry for the SINGS/KINGFISH Samples of Nearby Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Dale, D. A.; Turner, J. A. [Department of Physics and Astronomy, University of Wyoming, Laramie WY (United States); Cook, D. O. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena CA (United States); Roussel, H. [Institut d’Astrophysique de Paris, Sorbonne Universités, Paris (France); Armus, L.; Helou, G. [Spitzer Science Center, California Institute of Technology, Pasadena, CA (United States); Bolatto, A. D. [Department of Astronomy, University of Maryland, College Park, MD (United States); Boquien, M. [Unidad de Astronomía, Universidad de Antofagasta, Antofagasta (Chile); Brown, M. J. I. [School of Physics and Astronomy, Monash University, Victoria 3800 (Australia); Calzetti, D. [Department of Astronomy, University of Massachusetts, Amherst MA (United States); Looze, I. De [Sterrenkundig Observatorium, Universiteit Gent, Gent (Belgium); Galametz, M. [European Southern Observatory, Garching (Germany); Gordon, K. D. [Space Telescope Science Institute, Baltimore MD (United States); Groves, B. A. [Research School of Astronomy and Astrophysics, Australian National University, Canberra (Australia); Jarrett, T. H. [Astronomy Department, University of Capetown, Rondebosch (South Africa); Herrera-Camus, R. [Max-Planck-Institut für Extraterrestrische Physik, Garching (Germany); Hinz, J. L. [Steward Observatory, University of Arizona, Tucson AZ (United States); Hunt, L. K. [INAF—Osservatorio Astrofisico di Arcetri, Firenze (Italy); Kennicutt, R. C. [Institute of Astronomy, University of Cambridge, Cambridge (United Kingdom); Murphy, E. J., E-mail: ddale@uwyo.edu [National Radio Astronomy Observatory, Charlottesville, VA (United States); and others

    2017-03-01

    We present an update to the ultraviolet-to-radio database of global broadband photometry for the 79 nearby galaxies that comprise the union of the KINGFISH (Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel ) and SINGS ( Spitzer Infrared Nearby Galaxies Survey) samples. The 34-band data set presented here includes contributions from observational work carried out with a variety of facilities including GALEX , SDSS, Pan-STARRS1, NOAO , 2MASS, Wide-Field Infrared Survey Explorer , Spitzer , Herschel , Planck , JCMT , and the VLA. Improvements of note include recalibrations of previously published SINGS BVR {sub C} I {sub C} and KINGFISH far-infrared/submillimeter photometry. Similar to previous results in the literature, an excess of submillimeter emission above model predictions is seen primarily for low-metallicity dwarf or irregular galaxies. This 33-band photometric data set for the combined KINGFISH+SINGS sample serves as an important multiwavelength reference for the variety of galaxies observed at low redshift. A thorough analysis of the observed spectral energy distributions is carried out in a companion paper.

  13. Morphology and Structures of Nearby Dwarf Galaxies

    Science.gov (United States)

    Seo, Mira; Ann, HongBae

    2015-08-01

    We performed an analysis of the structure of nearby dwarf galaxies based on a 2-dimensional decomposition of galaxy images using GALFIT. The present sample consists of ~1,100 dwarf galaxies with redshift less than z = 0.01, which is is derived from the morphology catalog of the Visually classified galaxies in the local universe (Ann, Seo, and Ha 2015). In this catalog, dwarf galaxies are divided into 5 subtypes: dS0, dE, dSph, dEbc, dEblue with distinction of the presence of nucleation in dE, dSph, and dS0. We found that dSph and dEblue galaxies are fainter than other subtypes of dwarf galaxies. In most cases, single component, represented by the Sersic profile with n=1~1.5, well describes the luminosity distribution of dwarf galaxies in the present sample. However, a significant fraction of dS0, dEbc, and dEbue galaxies show sub-structures such as spiral arms and rings. We will discuss the morphology dependent evolutionary history of the local dwarf galaxies.

  14. Latest results of the Tunka Radio Extension

    Directory of Open Access Journals (Sweden)

    Kostunin D.

    2017-01-01

    Full Text Available The Tunka Radio Extension (Tunka-Rex is an antenna array consisting of 63 antennas at the location of the TAIGA facility (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy in Eastern Siberia, nearby Lake Baikal. Tunka-Rex is triggered by the air-Cherenkov array Tunka-133 during clear and moonless winter nights and by the scintillator array Tunka-Grande during the remaining time. Tunka-Rex measures the radio emission from the same air-showers as Tunka-133 and Tunka-Grande, but with a higher threshold of about 100 PeV. During the first stages of its operation, Tunka-Rex has proven, that sparse radio arrays can measure air-showers with an energy resolution of better than 15% and the depth of the shower maximum with a resolution of better than 40 g/cm2. To improve and interpret our measurements as well as to study systematic uncertainties due to interaction models, we perform radio simulations with CORSIKA and CoREAS. In this overview we present the setup of Tunka-Rex, discuss the achieved results and the prospects of mass-composition studies with radio arrays.

  15. 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.

  16. Young Star Clusters In Nearby Molecular Clouds

    Science.gov (United States)

    Getman, K. V.; Kuhn, M. A.; Feigelson, E. D.; Broos, P. S.; Bate, M. R.; Garmire, G. P.

    2018-02-01

    The SFiNCs (Star Formation in Nearby Clouds) project is an X-ray/infrared study of the young stellar populations in 22 star forming regions with distances ≲ 1 kpc designed to extend our earlier MYStIX survey of more distant clusters. Our central goal is to give empirical constraints on cluster formation mechanisms. Using parametric mixture models applied homogeneously to the catalog of SFiNCs young stars, we identify 52 SFiNCs clusters and 19 unclustered stellar structures. The procedure gives cluster properties including location, population, morphology, association to molecular clouds, absorption, age (AgeJX), and infrared spectral energy distribution (SED) slope. Absorption, SED slope, and AgeJX are age indicators. SFiNCs clusters are examined individually, and collectively with MYStIX clusters, to give the following results. (1) SFiNCs is dominated by smaller, younger, and more heavily obscured clusters than MYStIX. (2) SFiNCs cloud-associated clusters have the high ellipticities aligned with their host molecular filaments indicating morphology inherited from their parental clouds. (3) The effect of cluster expansion is evident from the radius-age, radius-absorption, and radius-SED correlations. Core radii increase dramatically from ˜0.08 to ˜0.9 pc over the age range 1 - 3.5 Myr. Inferred gas removal timescales are longer than 1 Myr. (4) Rich, spatially distributed stellar populations are present in SFiNCs clouds representing early generations of star formation. An Appendix compares the performance of the mixture models and nonparametric Minimum Spanning Tree to identify clusters. This work is a foundation for future SFiNCs/MYStIX studies including disk longevity, age gradients, and dynamical modeling.

  17. Proper motion survey for solar nearby stars

    International Nuclear Information System (INIS)

    Goldman, Bertrand

    2001-01-01

    For its microlensing observations EROS 2 built one of the largest CCD mosaic opera ting since 1996. This instrument allowed us to survey a large area of the sky, to look for faint, cool compact objects in the Solar neighborhood that may contribute to the Dark Matter revealed by flat rotation curves of spiral galaxies and the Milky Way. We imaged over 400 square degrees, at least three times over four years, with a single, stable instrument. The aim of this work is the reduction, the analysis and the detection of high proper motion objects that would look like those expected in a dark halo. We selected and analyzed thousands of images taken in two bands, visible and near-infrared, and obtained a catalogue of several thousand stars with proper motion typically higher than 80 milli-arc-seconds per year. None of these candidates displays the expected properties of the halo objects: very high proper motion and faintness. The second part of our work was to put constraints on the contributions of white dwarfs and brown dwarfs ta the halo. To do that, we simulated our data set and estimated our sensitivity to halo objects. We compared our results about moderately high proper motion stars with existing Galactic models, and confirmed the robustness of these models. We deduced a upper limit ta the contribution of M v = 17.5 white dwarfs to the standard halo of 10% (at the 95% confidence level), or 5% of a 14 Gyr old halo, and to the contribution of brown dwarfs of 7% (95% C.L.). Finally, among our candidates, several interesting objects, that do not belong to the halo but are among the coolest and faintest known, have been discovered. Systematic search for faint, nearby objects thus lead us to study disk L dwarfs, as well as old white dwarfs of the disk. (author) [fr

  18. Dual Active Galactic Nuclei in Nearby Galaxies

    Science.gov (United States)

    Das, Mousumi; Rubinur, Khatun; Karb, Preeti; Varghese, Ashlin; Novakkuni, Navyasree; James, Atul

    2018-04-01

    Galaxy mergers play a crucial role in the formation of massive galaxies and the buildup of their bulges. An important aspect of the merging process is the in-spiral of the supermassive black-holes (SMBHs) to the centre of the merger remnant and the eventual formation of a SMBH binary. If both the SMBHs are accreting they will form a dual or binary active galactic nucleus (DAGN). The final merger remnant is usually very bright and shows enhanced star formation. In this paper we summarise the current sample of DAGN from previous studies and describe methods that can be used to identify strong DAGN candidates from optical and spectroscopic surveys. These methods depend on the Doppler separation of the double peaked AGN emission lines, the nuclear velocity dispersion of the galaxies and their optical/UV colours. We describe two high resolution, radio observations of DAGN candidates that have been selected based on their double peaked optical emission lines (DPAGN). We also examine whether DAGN host galaxies have higher star formation rates (SFRs) compared to merging galaxies that do not appear to have DAGN. We find that the SFR is not higher for DAGN host galaxies. This suggests that the SFRs in DAGN host galaxies is due to the merging process itself and not related to the presence of two AGN in the system.

  19. 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

  20. 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...

  1. A radio pulsar/x-ray binary link.

    Science.gov (United States)

    Archibald, Anne M; Stairs, Ingrid H; Ransom, Scott M; Kaspi, Victoria M; Kondratiev, Vladislav I; Lorimer, Duncan R; McLaughlin, Maura A; Boyles, Jason; Hessels, Jason W T; Lynch, Ryan; van Leeuwen, Joeri; Roberts, Mallory S E; Jenet, Frederick; Champion, David J; Rosen, Rachel; Barlow, Brad N; Dunlap, Bart H; Remillard, Ronald A

    2009-06-12

    Radio pulsars with millisecond spin periods are thought to have been spun up by the transfer of matter and angular momentum from a low-mass companion star during an x-ray-emitting phase. The spin periods of the neutron stars in several such low-mass x-ray binary (LMXB) systems have been shown to be in the millisecond regime, but no radio pulsations have been detected. Here we report on detection and follow-up observations of a nearby radio millisecond pulsar (MSP) in a circular binary orbit with an optically identified companion star. Optical observations indicate that an accretion disk was present in this system within the past decade. Our optical data show no evidence that one exists today, suggesting that the radio MSP has turned on after a recent LMXB phase.

  2. La radio digital

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Cortés S.

    2015-01-01

    Full Text Available La radio digital es un producto de la llamada convergencia digital. Las nuevas tecnologías interconectadas permiten la aparición de nuevos modos de audiencia y la implementación de herramientas versátiles. Habla del problema de los estándares, de la radio satelital, la radio digital terrestre, las radios internacionales, la interactividad.

  3. Ionosphere and Radio Communication

    Indian Academy of Sciences (India)

    ionosphere is used for radio communication and navigation as it reflects long, medium, as well as short radio waves. Since solar radiation is the main cause of the existence of iono- sphere, any variation in the radiations can affect the entire radio communication system. This article attempts to briefly introduce the readers to ...

  4. Symposium “Mapping the Galaxy and Nearby Galaxies”

    CERN Document Server

    Wada, Keiichi; ASTROPHYSICS AND SPACE SCIENCE PROCEEDINGS

    2008-01-01

    This is a proceedings book of the symposium "Mapping the Galaxy and Nearby Galaxies" held on Ishigaki Island, Okinawa, Japan, on June 25 – 30, 2006. The symposium focused on mapping the interstellar media and other components in galaxies. Latest results of the following main topics are presented in the volume: Our Galaxy -- mass distribution, local ISM, supermassive black holes and their environments Central part of nearby galaxies -- ISM around starbursts, fueling mechanisms Nearby Galaxies -- molecular gas and star formation, gas dynamics Galactic environment and evolution -- formation of our Galaxy, origin of supermassive black holes The nature of the Dark Matter component -- effects on the internal structures of galaxies

  5. Position coincidence optical identifications using Texas interferometer radio positions

    International Nuclear Information System (INIS)

    Bozyan, E.P.

    1979-01-01

    1048 radio source positions measured with the Texas Interferometer were searched for optical identifications on glass copies of the Palomar Sky Survey E and O plates, resulting in 242 identifications and 806 blank fields. Finding charts are presented for 124 of the 125 new identifications not previously reported in the literature, and for 73 blank fields containing nearby optical objects which may be real identifications. This brings the cumulative number of Texas radio positions searched to 2015, producing 864 optical identifications and 1151 blank fields

  6. 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

  7. 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.

  8. The Effects of Nearby Clusters of Galaxies on the Microwave Background Radiation

    Science.gov (United States)

    Birkinshaw, M.

    1999-01-01

    This project proposed to use the COBE (Cosmic Background Explorer) DMR sky-maps to measure the anisotropies introduced into the microwave background radiation by the Sunyaev-Zel'dovich and Rees-Sciama effects of nearby clusters and superclusters of galaxies. We intended to seek these effects by making maps of the best-fit anisotropies on particular angular scales and comparing the apparent anisotropies near target clusters and superclusters with the statistical noise and sky variance. The locations of the clusters and superclusters were to be found using HEAO-1 (High Energy Astronomy Observatory) A2 and Einstein X-ray maps. Checks against biases were to be made using radio and X-ray sky-maps as guides to the properties of the clusters and superclusters. Any signals detected would have implications for the gas properties and baryonic masses of clusters and superclusters. The scientific background, project activities and references to published papers are included.

  9. Survey Layanan Publik Pemantauan Frekuensi Radio untuk Radio Amatir Dan Radio Antar Penduduk Indonesia

    OpenAIRE

    Azwar Aziz

    2014-01-01

    Berlatar belakang fenomena penggunaan amatir radio dan komunikasi radio antar penduduk yang berkaitan dengan faktor layanan publik dari monitor frekuensi radio, dimana peneliti memfokuskan pada permasalahan kondisi pelayanan publik yang diberikan oleh pemerintah tentang penggunaan radio non komersial yang digunakan oleh perorangan. Penelitian ini memperlihatkan penggiat amatir radio dan komunikasi radio antar penduduk bervariasi, mulai dari yang tidak mempunyai izin sampai pada yang memiliki ...

  10. First `Winged' and `X'-shaped Radio Source Candidates

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, C.C.

    2007-01-22

    A small number of double-lobed radio galaxies (17 from our own census of the literature) show an additional pair of low surface brightness ''wings'', thus forming an overall ''X''-shaped appearance. The origin of the wings in these radio sources is unclear. They may be the result of back-flowing plasma from the currently active radio lobes into an asymmetric medium surrounding the active nucleus, which would make these ideal systems in which to study thermal/non-thermal plasma interactions in extragalactic radio sources. Another possibility is that the wings are the aging radio lobes left over after a (rapid) realignment of the central supermassive black-hole/accretion disk system due perhaps to a merger. Generally, these models are not well tested; with the small number of known examples, previous works focused on detailed case studies of selected sources with little attempt at a systematic study of a large sample. Using the VLA-FIRST survey database, we are compiling a large sample of winged and X-shaped radio sources for such studies. As a first step toward this goal, an initial sample of 100 new candidate objects of this type are presented in this paper. The search process is described, optical identifications from available literature data, and basic radio data are presented. From the limited resolution FIRST images ({approx} 5''), we can already confidently classify a sufficient number of these objects as having the characteristic wing lengths >80% of the active lobes to more than double the number of known X-shaped radio sources. We have also included as candidates, radio sources with shorter wings (<80% wing to lobe length ratios), or simply ''winged'' sources, as it is probable that projection effects are important. Finally, among the candidates are four quasars (z=0.37 to 0.84), and several have morphologies suggestive of Fanaroff-Riley type-I (low-power) radio galaxies. While followup

  11. The limits of arousal's memory impairing effects on nearby information

    OpenAIRE

    Mather, Mara; Gorlick, Marissa; Nesmith, Kathryn

    2009-01-01

    Showing an arousing central stimulus in a scene often leads to enhanced memory for the arousing central information and impaired memory for peripheral details. However, it is not clear from previous work whether arousing stimuli impair memory for all non-arousing nearby information or just background information. In several experiments, we tested how emotionally arousing pictures affect memory for nearby pictures and for background information. We found that when two pictures were presented t...

  12. MaNGA: Mapping Nearby Galaxies at Apache Point Observatory

    Science.gov (United States)

    Weijmans, A.-M.; MaNGA Team

    2016-10-01

    MaNGA (Mapping Nearby Galaxies at APO) is a galaxy integral-field spectroscopic survey within the fourth generation Sloan Digital Sky Survey (SDSS-IV). It will be mapping the composition and kinematics of gas and stars in 10,000 nearby galaxies, using 17 differently sized fiber bundles. MaNGA's goal is to provide new insights in galaxy formation and evolution, and to deliver a local benchmark for current and future high-redshift studies.

  13. The Breakthrough Listen Search for Intelligent Life: Target Selection of Nearby Stars and Galaxies

    Science.gov (United States)

    Isaacson, Howard; Siemion, Andrew P. V.; Marcy, Geoffrey W.; Lebofsky, Matt; Price, Danny C.; MacMahon, David; Croft, Steve; DeBoer, David; Hickish, Jack; Werthimer, Dan; Sheikh, Sofia; Hellbourg, Greg; Enriquez, J. Emilio

    2017-05-01

    We present the target selection for the Breakthrough Listen search for extraterrestrial intelligence during the first year of observations at the Green Bank Telescope, Parkes Telescope, and Automated Planet Finder. On the way to observing 1,000,000 nearby stars in search of technological signals, we present three main sets of objects we plan to observe in addition to a smaller sample of exotica. We chose the 60 nearest stars, all within 5.1 pc from the Sun. Such nearby stars offer the potential to observe faint radio signals from transmitters that have a power similar to those on Earth. We add a list of 1649 stars drawn from the Hipparcos catalog that span the Hertzprung-Russell diagram, including all spectral types along the main sequence, subgiants, and giant stars. This sample offers diversity and inclusion of all stellar types, but with thoughtful limits and due attention to main sequence stars. Our targets also include 123 nearby galaxies composed of a “morphological-type-complete” sample of the nearest spirals, ellipticals, dwarf spherioidals, and irregulars. While their great distances hamper the detection of technological electromagnetic radiation, galaxies offer the opportunity to observe billions of stars simultaneously and to sample the bright end of the technological luminosity function. We will also use the Green Bank and Parkes telescopes to survey the plane and central bulge of the Milky Way. Finally, the complete target list includes several classes of exotica, including white dwarfs, brown dwarfs, black holes, neutron stars, and asteroids in our solar system.

  14. Not Dead Yet: Low-Level Star Formation and Active Nuclei in the Continued Evolution of Nearby Early-Type Galaxies

    Science.gov (United States)

    Nyland, Kristina; Young, Lisa; Wrobel, Joan; Morganti, Raffaella; Atlas-3D

    2015-01-01

    We present the results of sensitive Jansky Very Large Array continuum observations of nearby early-type galaxies (ETGs) at 1.4 and 5 GHz. Our sample comprises a subset of the volume- and magnitude-limited ATLAS-3D survey of ETGs, which has a rich database of ancillary data including CO observations. The 1.4 GHz observations were designed to explore the properties of star formation (SF) in ETGs at ~5' (~300 pc) spatial resolution. Here, we find that some CO-rich ETGs have radio luminosities consistent with extrapolations from H2 mass-derived SF rates (SFRs) and standard radio-SFR calibrations. However, at low H2 masses, many have weaker radio emission than expected. The infrared-radio relation shows similar behavior at low luminosities, with a systematic tendency for ETGs to lie below the standard infrared-radio relation developed for spirals, even when substantial reservoirs of H2 are available. Thus, many nearby ETGs are radio deficient compared to both their H2 and infrared emission. Several mechanisms likely conspire to cause this, but evidence is most compelling for a combination of decreased SF efficiency, a bottom-heavy IMF, weak magnetic fields, and higher incidence of environmental effects compared to spirals.We also study the prevalence and properties of 5~GHz radio cores at subarcsecond (~30 pc) resolution for two distinct kinematic classes: slow rotators (SRs) and fast rotators (FRs). SRs preferentially host nuclear radio emission compared to FRs, and they also host the most powerful radio sources in our sample, consistent with previous findings for ellipticals. In contrast to FRs, SRs also show signs of relationships between radio luminosity and stellar mass. In both FRs and SRs, the presence of dust and ionized gas are strong predictors of the detection of a radio core. All of this suggests that the nuclear activity in ETGs is related to their formation histories. In this picture, FRs are built-up by minor mergers and interactions that leave behind

  15. 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

  16. Senior radio listeners

    DEFF Research Database (Denmark)

    Blaakilde, Anne Leonora

    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...... 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...

  17. FROM NEARBY LOW LUMINOSITY AGN TO HIGH REDSHIFT ...

    Indian Academy of Sciences (India)

    44

    of web-based citizen-scientists project (Radio Galaxy. Zoo), Mao et al. (2015) detected another such galaxy, .... 620 kpc, in a deep GMRT study at 235 and 610 MHz. (Pandey-Pommier et al. 2016, in preparation). Could ..... source in the deep 150 MHz images with the GMRT, im- plying that the deeper radio surveys at low ...

  18. Simultaneous, multi-wavelength flare observations of nearby low-mass stars

    Science.gov (United States)

    Thackeray, Beverly; Barclay, Thomas; Quintana, Elisa; Villadsen, Jacqueline; Wofford, Alia; Schlieder, Joshua; Boyd, Patricia

    2018-01-01

    Low-mass stars are the most common stars in the Galaxy and have been targeted in the tens-of-thousands by K2, the re-purposed Kepler mission, as they are prime targets to search for and characterize small, Earth-like planets. Understanding how these fully convective stars drive magnetic activity that manifests as stochastic, short-term brightenings, or flares, provides insight into the prospects of planetary habitability. High energy radiation and energetic particle emission associated with these stars can erode atmospheres, and impact habitability. An innovative campaign to study low mass stars through simultaneous multi-wavelength observations is currently underway with observations ongoing in the X-ray, UV, optical, and radio. I will present early results of our pilot study of the nearby M-Dwarf star Wolf 359 (CN Leo) using K2, SWIFT, and ground based radio observatories, forming a comprehensive picture of flare activity from an M-Dwarf, and discuss the potential impact of these results on exoplanets. "This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE1322106. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation."

  19. Senior radio listeners

    DEFF Research Database (Denmark)

    Blaakilde, Anne Leonora

    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...... 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...

  20. Initial Hubble Diagram Results from the Nearby Supernova Factory

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, S. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France); Aldering, G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Antilogus, P. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France); Aragon, C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Baltay, C. [Yale Univ., New Haven, CT (United States); Bongard, S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Buton, C [Inst. of Nuclear Physics of Lyon (France); Childress, M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Copin, Y. [Inst. of Nuclear Physics of Lyon (France); Gangler, E. [Inst. of Nuclear Physics of Lyon (France); Loken, S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Nugent, P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Pain, R. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France); Pecontal, E. [Center of Research Astrophysics of Lyon (CRAL) (France); Pereira, R. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France); Perlmutter, S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rabinowitz, D. [Yale Univ., New Haven, CT (United States); Rigaudier, G. [Center of Research Astrophysics of Lyon (CRAL) (France); Ripoche, P. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France); Runge, K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Scalzo, R. [Yale Univ., New Haven, CT (United States); Smadja, G. [Inst. of Nuclear Physics of Lyon (France); Tao, C. [Inst. of Nuclear Physics of Lyon (France); Thomas, R. C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wu, C. [Lab. Nuclear and High-Energy Physics (LPNHE), Paris (France)

    2017-07-06

    The use of Type Ia supernovae as distance indicators led to the discovery of the accelerating expansion of the universe a decade ago. Now that large second generation surveys have significantly increased the size and quality of the high-redshift sample, the cosmological constraints are limited by the currently available sample of ~50 cosmologically useful nearby supernovae. The Nearby Supernova Factory addresses this problem by discovering nearby supernovae and observing their spectrophotometric time development. Our data sample includes over 2400 spectra from spectral timeseries of 185 supernovae. This talk presents results from a portion of this sample including a Hubble diagram (relative distance vs. redshift) and a description of some analyses using this rich dataset.

  1. 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

  2. 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 ...

  3. 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,…

  4. Cosmic Extremes: Probing Energetic Transients with Radio Observations

    Science.gov (United States)

    Denham Alexander, Kate

    2018-01-01

    With the advent of sensitive facilities like the Karl G. Jansky Very Large Array (VLA) and planning well underway for vastly more powerful wide-field interferometers like the Square Kilometer Array, the study of radio astrophysical transients is poised for dramatic growth. Radio observations provide a unique window into a wide variety of transient events, from gamma-ray bursts (GRBs) to supernovae to tidal disruption events (TDEs) in which a star is torn apart by a supermassive black hole. In particular, GRBs and TDEs have emerged as valuable probes of some of the most extreme physics in the Universe. In these high-energy laboratories, the longer timescale of radio emission allows for extensive followup and characterization of the event energies and the densities of surrounding material. I will present high-cadence broadband radio studies of GRB afterglows and TDEs undertaken with the goal of learning more about their physical properties, the physics underlying the formation and growth of relativistic jets and outflows, and the environments in which these events occur. Our observations confirm that only a small fraction of TDEs produce relativistic jets but reveal low-luminosity, non-relativistic outflows in two nearby TDEs, allowing us to begin constraining the bulk of the TDE population. Our GRB radio observations reveal both intrinsic variability (reverse shocks) and extrinsic variability (interstellar scintillation). The insights derived from these studies will be invaluable for designing and interpreting the results from future radio transient surveys.

  5. Abundance analysis of giant H II regions in nearby spirals

    OpenAIRE

    Díaz, Angeles I.; Terlevich, E.; Pagel, B.E.J.; Vílchez, J.M; Edmunds, M.G.

    1990-01-01

    This is an electronic version of an article published in Revista Mexicana de Astronomía y Astrofísica. Díaz, Angeles I. et al. Abundance analysis of giant H II regions in nearby spirals. Revista Mexicana de Astronomía y Astrofísica 21 (1990): 223-227

  6. Prospects for SODART observations of nearby clusters of galaxies

    DEFF Research Database (Denmark)

    Pedersen, Kenneth; Westergaard, Niels Jørgen Stenfeldt

    1998-01-01

    Using the current best understanding of the SODART mirror system, the Bragg panel and of the LEPC/HEPC responses [1] we have studied the feasibility and prospects for SODART studies of nearby clusters of galaxies. From simulated HEPC data of the cluster Abell 2256, we demonstrate that SODART...

  7. Evidence of nearby supernovae affecting life on Earth

    DEFF Research Database (Denmark)

    Svensmark, Henrik

    2012-01-01

    . A statistical analysis indicates that the Solar system has experienced many large short-term increases in the flux of Galactic cosmic rays (GCR) from nearby SNe. The hypothesis that a high GCR flux should coincide with cold conditions on the Earth is borne out by comparing the general geological record...

  8. Unlocking radio broadcasts

    DEFF Research Database (Denmark)

    Skov, Mette; Lykke, Marianne

    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...

  9. 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.

  10. 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.

  11. VLA Observations of the Nearby Merger NGC 4038/4039: H II Regions and Supernova Remnants in the ``Antennae''

    Science.gov (United States)

    Neff, Susan G.; Ulvestad, James S.

    2000-08-01

    We present 6 and 4 cm radio images of the inner disks of the nearby merger pair NGC 4038 and NGC 4039 at resolutions between ~1'' and 2.6", or ~100 and 260 pc. We detect numerous compact radio sources embedded in more diffuse radio emission; the compact radio sources produce ~12% and ~25% of the 6 and 4 cm radio emission in the system, respectively. The strongest radio continuum emission occurs between the galaxies, at an optically unremarkable location near but not coincident with an extremely red cluster detected by Whitmore & Schweizer. The radio peak is at a location of intense star formation (as detected in the mid-IR) and of dense molecular gas. We identify 115 individual compact 6 cm radio sources and 63 individual 4 cm sources in the system, to a limiting luminosity of ~2×1018 W Hz-1, or ~4 times the luminosity of Cas A; 90% of the 6 cm sources and 67% of the 4 cm sources are unresolved in these observations. Of the strongest sources, for which the flux densities are large enough to measure spectral indices with reasonable errors, one-third have nominally flat radio spectra, indicating that they are dominated by thermal radio emission from H II regions, and two-thirds have nominally steep spectra dominated by nonthermal emission from supernova remnants. For the compact sources dominated by thermal emission, we derive typical masses of 104 to 105 Msolar in massive young stars. Using reasonable assumptions about source sizes, we estimate associated ionized gas masses of 103 to 104 Msolar. A comparison with the ~(2-5)×103 Msolar typical optical clusters detected recently by Whitmore et al. suggests that the thermal radio sources detected here may be composed of tens of these typical young star clusters or else that they are more like the individual massive 105-106 Msolar Whitmore et al. clusters. The strongest thermal radio source is associated with none of the Whitmore et al. clusters but is coincident with strong CO and 15 μm emission, implying that

  12. Advanced sensing techniques for cognitive radio

    CERN Document Server

    Zhao, Guodong; Li, Shaoqian

    2017-01-01

    This SpringerBrief investigates advanced sensing techniques to detect and estimate the primary receiver for cognitive radio systems. Along with a comprehensive overview of existing spectrum sensing techniques, this brief focuses on the design of new signal processing techniques, including the region-based sensing, jamming-based probing, and relay-based probing. The proposed sensing techniques aim to detect the nearby primary receiver and estimate the cross-channel gain between the cognitive transmitter and primary receiver. The performance of the proposed algorithms is evaluated by simulations in terms of several performance parameters, including detection probability, interference probability, and estimation error. The results show that the proposed sensing techniques can effectively sense the primary receiver and improve the cognitive transmission throughput. Researchers and postgraduate students in electrical engineering will find this an exceptional resource.

  13. H I observations of nearby galaxies. III. More dwarf galaxies in the northern sky

    Science.gov (United States)

    Karachentsev, I. D.; Karachentseva, V. E.; Huchtmeier, W. K.

    2001-02-01

    We carried out a systematic search for nearby dwarf galaxies in the northern sky based on POSS-II film copies. As a result we present a list of 101 nearby dwarf galaxy candidates mainly of low surface brightness which have angular diameters a>~ 0farcm5 . About two thirds of the objects are new discoveries. This sample is considered as a supplement to the 163 northern dwarf galaxy candidates (A&AS, 1998, 127, 409) which have been detected in the same declination range around the known Local Volume galaxies and to the 78 dwarf galaxy candidates (A&AS, 1999, 135, 221) in the Local Void region. All the galaxies were observed in {H I with the 100-m Effelsberg radio telescope with a detection rate of 46%. The sample of detected galaxies has the following median parameters: radial velocity V_LG = +770 km s-1, {H I line width W50 = 46 km s-1, absolute blue magnitude M_B = -13.8 mag, linear diameter A0 = 2.7 kpc, hydrogen mass-to-luminosity ratio M_HI/L_B = 1.2\\ Msun/Lsun, and the HI mass-to-total mass ratio Mion {H i}/M_t=0.28. Tables~1 and~2 are also 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/366/428 Figure~1 is only available at http://www.edpsciences.org

  14. 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....

  15. 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.

  16. 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)

  17. 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.

  18. ¿Radios ciudadanas?

    OpenAIRE

    López Vigil, José Ignacio

    1998-01-01

    Educativas, sindicales, populares, comunitarias, libres, rebeldes, participativas, alternativas, alterativas, han sido las denominaciones de la radio cuando su proyecto está al servicio de la gente. Palabras apropiadas y nobles -dice elautor-pero devaluadas, a las que ahora se agrega la radio ciudadana, para relievarla como ejercicio depoder y espacio de verdadera participación de la genteenla vida de su nación.

  19. 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...

  20. Astrometry of southern radio sources

    Science.gov (United States)

    White, Graeme L.; Jauncey, David L.; Harvey, Bruce R.; Savage, Ann; Gulkis, Samuel; Preston, Robert A.

    1991-01-01

    An overview is presented of a number of astrometry and astrophysics programs based on radio sources from the Parkes 2.7 GHz catalogs. The programs cover the optical identification and spectroscopy of flat-spectrum Parkes sources and the determination of their milliarcsecond radio structures and positions. Work is also in progress to tie together the radio and Hipparcos positional reference frames. A parallel program of radio and optical astrometry of southern radio stars is also under way.

  1. Blue optical continuum associated with a radio knot in 3C346

    Science.gov (United States)

    Dey, Arjun; van Breugel, Wil J. M.

    1994-06-01

    We report the discovery of extremely luminous near-UV continuum emission associated with a bright radio knot in the radio galaxy 3C346 (zeta = 0.162). Photometric measurements from U and r' band images and longslit spectra show a spectral energy distribution that steepens at higher frequencies, with radio and optical spectral indices alphar = -0.37 +/- 0.02 and alphao = -1.8 +/- 0.2, respectively. Based on a comparison of the optical properties of this knot with other known cases of optical emission associated with radio structures, we conclude that the continuum emission is optical synchrotron radiation. Our observations are consistent with the suggestion that 3C346 is a foreshortened FR-II radio galaxy with its radio axis oriented close to the line of sight. The optical and radio emission from the knot appear to be associated with a hotspot (at the end of a jet) on the near side. Finally, our U and r' images of 3C346 provide a striking illustration that the optical morphologies of nearby radio galaxies also depend upon wavelength and that studies of these objects are relevant to the interpretation of the alignment effect seen in the high redshift radio galaxies.

  2. The Long Term Features of Tropical Cyclones Nearby Taiwan

    Science.gov (United States)

    Wu, Yueh-Shyuan; Lee, Cheng-Shang

    2017-04-01

    Tropical cyclone (TC) activity is affected by several factors. The variability of TC activity over the western North Pacific (WNP) has been examined in the past decade. Previous studies showed that TC activity (such as TC number, intensity and tracks) has multiscale variation or affected by natural oscillation of different scales. However, most of these studies focused mainly on the entire WNP. Very few studies examined the variability of annual TC track or the variability of TC number in the area nearby Taiwan, which caused severe economic loss and life damage to Taiwan in the typhoon season. The main purpose of this study is to analyze the variation of TC activity nearby Taiwan to address its long term features, and also the possible relationship with the associated flow patterns. Preliminary results of wavelet analysis showed that the TC number nearby Taiwan during 1970-2014 had multiscale variations. The following analysis focused on the scale about 4- and 11-year signals, in the targeted area of 118o-125oE, 20o-27oN. The positive phases of both scale 4 and scale 11 showed a tendency of TC tracks toward Taiwan area, while the negative phases showed a lower tendency toward Taiwan. An empirical orthogonal function (EOF) analysis was applied on the 4-yr and the 11-yr filtered 500-hPa wind fields and geopotential heights. Results showed that the 4-yr signal was mostly dominated by the 500-hPa U- and V-wind fields, suggesting that the TC track patterns were affected mainly by the midlevel steering flow. On the other hand, the 11-yr signal was mostly dominated by the 500-hPa U-wind field and geopotential anomalies, indicating that the main cause of the difference in TC occurrence nearby Taiwan was the location of TC formation.

  3. Farmers’ awareness on environmental degradation nearby the brickfield areas

    OpenAIRE

    Hasan, M.B.; Ali, M.A.; Alam, M.S.; Bhuyian, M.A.S.

    2012-01-01

    This study was undertaken at Trishal upazila of Mymensingh, Bangladesh to investigate the farmers’ awareness on environmental degradation nearby the brickfield areas and to explore the relationship between the selected characteristics of the farmers (i.e. independent variables) with their awareness on environmental degradation (i.e. dependent variable). Thirty five farmers were selected randomly from a total of 175 farmers under Amiandangori village of Balipara union and thirty farmers were s...

  4. A WISE Survey of Star Formation in Nearby Molecular Clouds

    Science.gov (United States)

    Huard, Tracy

    During the last decade, sensitive mid-infrared observations obtained by the Spitzer Space Telescope significantly increased the known population of Young Stellar Objects (YSOs) associated with nearby molecular clouds. With such a census, recent studies have derived efficiencies of the star formation rates in the different environments. Given the small Spitzer coverage of these molecular clouds, relative to their large extended regions, these YSO populations may represent a limited view of star formation in these regions. We propose to take advantage of mid-infrared observations from the recent WISE mission, which provides an all-sky view and therefore full coverage of the nearby molecular clouds, to assess the degree to which their currently known YSO populations may be under-representative of the extended, more complete populations. We will extend and apply the well established classification method, developed by Spitzer Legacy teams, to archived WISE observations in order to identify and assemble a more complete census of YSOs associated with nearby clouds. Large-scale, high angular resolution extinction maps covering the full extent of these clouds will also be constructed in a uniform manner to enable cross-comparison studies of star formation rates in these different environments. Finally, we plan to provide enhanced WISE data products to the community through the Infrared Processing and Analysis Center, which will promote a diversity of studies by a wider group of investigators, facilitate star-formation studies across different environments, and help ensure the legacy of WISE data.

  5. Doses of Nearby Nature Simultaneously Associated with Multiple Health Benefits

    Directory of Open Access Journals (Sweden)

    Daniel T. C. Cox

    2017-02-01

    Full Text Available Exposure to nature provides a wide range of health benefits. A significant proportion of these are delivered close to home, because this offers an immediate and easily accessible opportunity for people to experience nature. However, there is limited information to guide recommendations on its management and appropriate use. We apply a nature dose-response framework to quantify the simultaneous association between exposure to nearby nature and multiple health benefits. We surveyed ca. 1000 respondents in Southern England, UK, to determine relationships between (a nature dose type, that is the frequency and duration (time spent in private green space and intensity (quantity of neighbourhood vegetation cover of nature exposure and (b health outcomes, including mental, physical and social health, physical behaviour and nature orientation. We then modelled dose-response relationships between dose type and self-reported depression. We demonstrate positive relationships between nature dose and mental and social health, increased physical activity and nature orientation. Dose-response analysis showed that lower levels of depression were associated with minimum thresholds of weekly nature dose. Nearby nature is associated with quantifiable health benefits, with potential for lowering the human and financial costs of ill health. Dose-response analysis has the potential to guide minimum and optimum recommendations on the management and use of nearby nature for preventative healthcare.

  6. 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...

  7. Radio coverage statistics.

    Science.gov (United States)

    Lynn, W

    1984-01-01

    The Clearinghouse on Development Communication surveyed 135 countries in Asia, Africa, Europe, North and South America, for U.S.A.I.D., to determine the number of radio and television broadcast stations and receivers. Some of the data were obtained from the World Factbook, the World Radio and TV Handbook, and the World Radio and T.V. Facts and Figures, from 1979 to 1981. In those countries where stations are privately owned, audience surveys are often available. In 2 out of 3 developing countries, however, stations are government owned, and no such information is available. Numbers of receivers can sometimes be ascertained from receiver license applications. There is a need for more complete information on broadcast demographics, listening and viewing patterns by the community of world development program personnel.

  8. 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...

  9. Radio structure in quasars

    International Nuclear Information System (INIS)

    Barthel, P.D.

    1984-01-01

    In this thesis, observational attention is given to the extended extragalactic radio sources associated with quasars. The isolated compact radio sources, often identified with quasars, are only included in the discussions. Three aspects of the radio structure in quasars and their cosmic evolution are considered: a study of the parsec scale morphology in quasar cores, in relation to the extended morphologies; an investigation of possible epoch dependent hotspot properties as well as a more detailed investigation of this fine scale structure; a VLA project was carried out to obtain morphological information on scales of 0.5 arcsec on high redshift quasars and to investigate possible epoch dependent morphological properties. MERLIN observations at 0.1 arcsec resolution to supplement the VLA data were initiated. (Auth.)

  10. Allow for Uncertainty - Indeterminacy & RadioRadio Research 2013

    OpenAIRE

    Watson, Rob

    2013-01-01

    Radio is faced with the challenge of rapidly changing technology and social practices. How can the study of radio be adapted to account for these changes, and what issues will need to be prioritised in the future.

  11. Radio Emission from Supernovae

    International Nuclear Information System (INIS)

    Weiler, Kurt W.; Panagia, Nino; Sramek, Richard A.; Van Dyk, Schuyler D.; Williams, Christopher L.; Stockdale, Christopher J.; Kelley, Matthew T.

    2009-01-01

    Study of radio supernovae over the past 27 years includes more than three dozen detected objects and more than 150 upper limits. From this work it is possible to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the presupernova stellar wind, and reveal the last stages of stellar evolution before explosion. It is also possible to detect ionized hydrogen along the line of sight, to demonstrate binary properties of the presupernova stellar system, and to detect dumpiness of the circumstellar material.

  12. Identification and spectrophotometry of faint southern radio galaxies

    International Nuclear Information System (INIS)

    Spinrad, H.; Kron, R.G.; Hunstead, R.W.

    1980-01-01

    We have observed a mixed sample of southern radio sources, identified on the Palomar sky survey or on previous direct plates taken with medium-aperture reflectors. At CIO we obtained a few deep 4m photographs and SIT spectrophotometry for redshift and continuum-color measurement. Almost all our sources were faint galaxies; the largest redshift measured was for 3C 275, with z=0.480. The ultraviolet continuum of PKS 0400--643, a ''thermal'' galaxy with z=0.476, closely resembles that of 3C 295 and shows some color evolution in U--B compared to nearby giant ellipticals

  13. 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

  14. 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

  15. Radio Fatwa : Islamic Tanya-Jawab Programmes on Radio Dakwah

    NARCIS (Netherlands)

    Sunarwoto,

    2012-01-01

    The present article is a study of radio fatwa in Indonesia with special reference to the Tanya-Jawab genres in radio dakwah.The concept of fatwa has changed over time. Such Islamic Tanya-Jawab programmes broadcast on radio dakwah are important to understand how fatwa is disseminated by means of

  16. 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

  17. 75 FR 10439 - Cognitive Radio Technologies and Software Defined Radios

    Science.gov (United States)

    2010-03-08

    ..., such as keys, passwords or biometric data. 11. Finally, as software defined radio and security... concerning the use of open source software to implement security features in software defined radios (SDRs... radios; and (2) its policy on the confidentiality of software that controls security measures in software...

  18. The Mitchell Spectrograph: Studying Nearby Galaxies with the VIRUS Prototype

    Directory of Open Access Journals (Sweden)

    Guillermo A. Blanc

    2013-01-01

    Full Text Available The Mitchell Spectrograph (a.k.a. VIRUS-P on the 2.7 m Harlan J. Smith telescope at McDonald Observatory is currently the largest field of view (FOV integral field unit (IFU spectrograph in the world (1.7′×1.7′. It was designed as a prototype for the highly replicable VIRUS spectrograph which consists of a mosaic of IFUs spread over a 16′ diameter FOV feeding 150 spectrographs similar to the Mitchell. VIRUS will be deployed on the 9.2 meter Hobby-Eberly Telescope (HET and will be used to conduct the HET Dark Energy Experiment (HETDEX. Since seeing first light in 2007 the Mitchell Spectrograph has been widely used, among other things, to study nearby galaxies in the local universe where their internal structure and the spatial distribution of different physical parameters can be studied in great detail. These observations have provided important insight into many aspects of the physics behind the formation and evolution of galaxies and have boosted the scientific impact of the 2.7 meter telescope enormously. Here I review the contributions of the Mitchell Spectrograph to the study of nearby galaxies, from the investigation the spatial distribution of dark matter and the properties of supermassive black holes, to the studies of the process of star formation and the chemical composition of stars and gas in the ISM, which provide important information regarding the formation and evolution of these systems. I highlight the fact that wide field integral field spectrographs on small and medium size telescopes can be powerful cost effective tools to study the astrophysics of galaxies. Finally I briefly discuss the potential of HETDEX for conducting studies on nearby galaxies. The survey parameters make it complimentary and competitive to ongoing and future surveys like SAMI and MANGA.

  19. Gamma-rays Associated with Nearby Thunderstorms at Ground Level

    OpenAIRE

    Ringuette, Rebecca; Cherry, Michael L.; Granger, Douglas; Guzik, T. Gregory; Stewart, Michael; Wefel, John P.

    2014-01-01

    The TGF and Energetic Thunderstorm Rooftop Array (TETRA) is an array of NaI scintillators located at rooftop level on the campus of Louisiana State University in Baton Rouge, Louisiana. From July 2010 through March 2014, TETRA has detected 28 millisecond-duration bursts of gamma-rays at energies 50 keV - 2 MeV associated with nearby (< 8 km) thunderstorms. The ability to observe ground-level Terrestrial Gamma Flashes from close to the source allows a unique analysis of the storm cells produci...

  20. NEAR-INFRARED SPECTROSCOPY OF NEARBY SEYFERT GALAXIES: IS THERE EVIDENCE FOR SHOCK EXCITATION IN NARROW-LINE REGIONS?

    Energy Technology Data Exchange (ETDEWEB)

    Terao, K. [Graduate School of Science and Engineering, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577 (Japan); Nagao, T.; Toba, Y. [Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577 (Japan); Hashimoto, T. [National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan (China); Yanagisawa, K. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Honjo 3037-5, Kamogata-cho, Asaguchi, Okayama 719-0232 (Japan); Matsuoka, K. [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Ikeda, H. [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo, 181-8588 (Japan); Taniguchi, Y., E-mail: terao@cosmos.phys.sci.ehime-u.ac.jp [The Open University of Japan, Wakaba 2-11, Mihama-ku, Chiba 261-8586 (Japan)

    2016-12-20

    One of the important unsettled problems regarding active galactic nuclei (AGNs) is the major ionization mechanism of gas clouds in AGN narrow-line regions (NLRs). In order to investigate this issue, we present our J -band spectroscopic observations of a sample of 26 nearby Seyfert galaxies. In our study, we use the flux ratio of the following two forbidden emission lines, [Fe ii]1.257  μ m and [P ii]1.188  μ m, because it is known that this ratio is sensitive to the ionization mechanism. We obtain the [Fe ii]/[P ii] flux ratio or its lower limit for 19 objects. In addition to our data, we compile this flux ratio (or its lower limit) for 23 nearby Seyfert galaxies from the literature. Based on the collected data, we find that three Seyfert galaxies show very large lower limits of the [Fe ii]/[P ii] flux ratios (≳10): NGC 2782, NGC 5005, and Mrk 463. It is thus suggested that the contribution of the fast shock in the gas excitation is significantly large for them. However, more than half of the Seyfert galaxies in our sample show moderate [Fe ii]/[P ii] flux ratios (∼2), which is consistent with pure photoionization by power-law ionizing continuum emission. We also find that the [Fe ii]/[P ii] flux ratio shows no clear correlation with the radio loudness, suggesting that the radio jet is not the primary origin of shocks in NLRs of Seyfert galaxies.

  1. 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 ...

  2. Radio Frequency Identification

    Indian Academy of Sciences (India)

    Radio Frequency Identification (RFID) has been around sinceearly 2000. Its use has currently become commonplace as thecost of RFID tags has rapidly decreased. RFID tags have alsobecome more 'intelligent' with the incorporation of processorsand sensors in them. They are widely used now in manyinnovative ways.

  3. A Radio Production Course.

    Science.gov (United States)

    Novak, Glenn D.

    1983-01-01

    Provides a framework for an upper-level basic radio production course. Covers course structure, production assignments, equipment, studio/lab time, grading procedures, textbook and audiovisual materials. Emphasizes theory and practice to provide students with critical and production skills. (PD)

  4. 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

  5. Boom Booom Net Radio

    DEFF Research Database (Denmark)

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

    1999-01-01

    Internet radio is one of the growth areas of the Internet but, as this article will show, is fraught with difficulties and frustration for both the modestly-funded broadcaster (bitcaster) and the listener. The article will illustrate some of these problems by means of a short case study of an exi...

  6. Extreme Radio Flares and Associated X-Ray Variability from Young Stellar Objects in the Orion Nebula Cluster

    Energy Technology Data Exchange (ETDEWEB)

    Forbrich, Jan [Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Reid, Mark J.; Wolk, Scott J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138 (United States); Menten, Karl M. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Rivilla, Victor M. [Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125, Firenze (Italy); Rau, Urvashi; Chandler, Claire J. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States)

    2017-08-01

    Young stellar objects are known to exhibit strong radio variability on timescales of weeks to months, and a few reports have documented extreme radio flares with at least an order of magnitude change in flux density on timescales of hours to days. However, there have been few constraints on the occurrence rate of such radio flares or on the correlation with pre-main sequence X-ray flares, although such correlations are known for the Sun and nearby active stars. Here we report simultaneous deep VLA radio and Chandra X-ray observations of the Orion Nebula Cluster, targeting hundreds of sources to look for the occurrence rate of extreme radio variability and potential correlation with the most extreme X-ray variability. We identify 13 radio sources with extreme radio variability, with some showing an order of magnitude change in flux density in less than 30 minutes. All of these sources show X-ray emission and variability, but we find clear correlations with extreme radio flaring only on timescales <1 hr. Strong X-ray variability does not predict the extreme radio sources and vice versa. Radio flares thus provide us with a new perspective on high-energy processes in YSOs and the irradiation of their protoplanetary disks. Finally, our results highlight implications for interferometric imaging of sources violating the constant-sky assumption.

  7. 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…

  8. VLBI OBSERVATIONS OF THE NEARBY TYPE IIb SUPERNOVA 2011dh

    International Nuclear Information System (INIS)

    Bietenholz, M. F.; Brunthaler, A.; Soderberg, A. M.; Zauderer, B.; Krauss, M.; Chomiuk, L.; Rupen, M. P.; Bartel, N.

    2012-01-01

    We report on phase-referenced very long baseline interferometry radio observations of the Type IIb supernova 2011dh, at times t = 83 days and 179 days after the explosion and at frequencies, respectively, of 22.2 and 8.4 GHz. We detected SN 2011dh at both epochs. At the first epoch only an upper limit on SN 2011dh's angular size was obtained, but at the second epoch, we determine the angular radius of SN 2011dh's radio emission to be 0.25 ± 0.08 mas by fitting a spherical shell model directly to the visibility measurements. At a distance of 8.4 Mpc, this angular radius corresponds to a time-averaged (since t = 0) expansion velocity of the forward shock of 21, 000 ± 7000 km s –1 . Our measured values of the radius of the emission region are in excellent agreement with those derived from fitting synchrotron self-absorbed models to the radio spectral energy distribution, providing strong confirmation for the latter method of estimating the radius. We find that SN 2011dh's radius evolves in a power-law fashion, with R∝t 0.92±0.10 .

  9. The distribution of infrared point sources in nearby elliptical galaxies

    Science.gov (United States)

    Gogoi, Rupjyoti; Shalima, P.; Misra, Ranjeev

    2018-02-01

    Infrared (IR) point sources as observed by Spitzer, in nearby early-type galaxies should either be bright sources in the galaxy such as globular clusters, or they may be background sources such as AGNs. These objects are often counterparts of sources in other wavebands such as optical and X-rays and the IR information provides crucial information regarding their nature. However, many of the IR sources may be background objects and it is important to identify them or at least quantify the level of background contamination. Moreover, the distribution of these IR point sources in flux, distance from the centre and colour would be useful in understanding their origin. Archival Spitzer IRAC images provide a unique opportunity for such a study and here we present the results of such an analysis for four nearby galaxies, NGC 1399, NGC 2768, NGC 4365 and NGC 4649. We estimate the background contamination using several blank fields. Our results suggest that IR colours can be effectively used to differentiate between sources in the galaxy and background ones. In particular we find that sources having AGN like colours are indeed consistent with being background AGNs. For sources with non AGN like colours we compute the distribution of flux and normalised distance from the centre which is found to be of a power-law form. Although our sample size is small, the power-law index for the galaxies are different indicating perhaps that the galaxy environment may be playing a part in their origin and nature.

  10. Modelling the star formation histories of nearby elliptical galaxies

    Science.gov (United States)

    Bird, Katy

    Since Lick indices were introduced in 1994, they have been used as a source of observational data against which computer models of galaxy evolution have been compared. However, as this thesis demonstrates, observed Lick indices lead to mathematical ill-conditioning: small variations in observations can lead to very large differences in population synthesis models attempting to recreate the observed values. As such, limited reliance should be placed on any results currently or historically in the literature purporting to give the star formation history of a galaxy, or group of galaxies, where this is deduced from Lick observations taken from a single instrument, without separate verification from at least one other source. Within these limitations, this thesis also constrains the star formation histories of 21 nearby elliptical galaxies, finding that they formed 13.26 +0.09 -0.06 Gyrs ago, that all mergers are dry, and that galactic winds are formed from AGN activity (rather than being supernovae-driven). This thesis also finds evidence to support the established galaxy-formation theory of "downsizing". An existing galactic model from the literature is examined and evaluated, and the reasons for it being unable to establish star formation histories of individual galaxies are ascertained. A brand-new model is designed, developed, tested and used with two separate data sets, corroborated for 10 galaxies by data from a third source, and compared to results from a Single Stellar Population model from the literature, to model the star formation histories of nearby elliptical galaxies.

  11. The importance of Radio Quiet Zone (RQZ) for radio astronomy

    Science.gov (United States)

    Umar, Roslan; Abidin, Zamri Zainal; Ibrahim, Zainol Abidin

    2013-05-01

    Most of radio observatories are located in isolated areas. Since radio sources from the universe is very weak, astronomer need to avoid radio frequency interference (RFI) from active spectrum users and radio noise produced by human made (telecommunication, mobile phone, microwave user and many more. There are many observatories around the world are surrounded by a Radio Quiet Zone (RQZ), which is it was set up using public or state laws. A Radio Quiet Zone normally consists of two areas: an exclusive area in which totally radio emissions are forbidden, with restrictions for residents and business developments, and a larger (radius up to 100 km above) coordination area where the power of radio transmission limits to threshold levels. Geographical Information System (GIS) can be used as a powerful tool in mapping large areas with varying RQZ profiles. In this paper, we report the initial testing of the usage of this system in order to identify the areas were suitable for Radio Quiet Zone. Among the important parameters used to develop the database for our GIS are population density, information on TV and telecommunication (mobile phones) transmitters, road networks (highway), and contour shielding. We will also use other information gathered from on-site RFI level measurements on selected 'best' areas generated by the GIS. The intention is to find the best site for the purpose of establishing first radio quiet zones for radio telescope in Malaysia.

  12. Introduction to international radio regulations

    International Nuclear Information System (INIS)

    Radicella, S.M.

    2003-01-01

    These lecture notes contain an overview of basic problems of the International Radio Regulations. Access to the existing information infrastructure, and to that of the future Information Society, depends critically on radio, especially in poor, remote and sparsely populated regions with under-developed telecommunication infrastructure. How the spectrum of radio frequencies is regulated has profound impact on the society, its security, prosperity, and culture. The radio regulations represent a very important framework for an adequate use of radio and should be known by all of those working in the field

  13. Enormous Disc of Cool Gas Surrounding the Nearby Powerful Radio Galaxy NGC 612 (PKS 0131-36)

    Science.gov (United States)

    2008-05-22

    of dark matter is still under debate (see e.g. Romanowsky et al. 2003; Humphrey et al. 2006), but our derived value of Menc/LB for NGC 612 is in good...2002, New Astronomy Review, 46, 313 Raimann D., Storchi-Bergmann T., Quintana H., Hunstead R., Wisotzki L., 2005, MNRAS, 364, 1239 Romanowsky A. J

  14. Radio Telescopes Reveal Unseen Galactic Cannibalism

    Science.gov (United States)

    2008-06-01

    quasars and blazars are hundreds of times more powerful. The astronomers picked a number of relatively nearby Seyfert galaxies that had previously been observed with visible-light telescopes. They then carefully studied the Seyferts with the VLA, specifically looking for radio waves emitted by hydrogen atoms. The VLA images showed the vast majority of the Seyferts were disturbed by encounters with neighbor galaxies. By comparison, similar VLA images of inactive galaxies showed that very few were disturbed. "This comparison clearly shows a connection between close galactic encounters and the black-hole-powered activity in the cores," said Ya-Wen Tang, who began this work at the Institute of Astronomy & Astrophysics, Academia Sinica (ASIAA), in Taiwan and now is a graduate student at the National Taiwan University. "This is the best evidence yet for the fueling of Seyfert galaxies. Other mechanisms have been proposed, but they have shown little if any difference between Seyferts and inactive galaxies," Tang added. "Our results show that images of the hydrogen gas are a powerful tool for revealing otherwise-invisible gravitational interactions among galaxies," said Jeremy Lim, also of ASIAA. "This is a welcome advance in our understanding of these objects, made possible by the best and most extensive survey ever made of hydrogen in Seyferts," Lim said. Kuo, Tang and Lim worked with Paul Ho, of ASIAA and the Harvard-Smithsonian Center for Astrophysics. The scientists reported their findings in the Astrophysical Journal. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  15. Radio-capacity of ecosystems

    International Nuclear Information System (INIS)

    Kultakhmedov, Yu.; Kultakhmedova-Vyshnyakova, V.

    1997-01-01

    This paper consider a universal approach to ecosystems of different types, based on representation of their radio-capacity. The concept of ecosystem includes reproduction of components (bio-productivity) and conditions such as maintaining of environment quality. Radio-capacity in the case of radionuclide pollution appears in accumulation and redistribution of radionuclides in the ecosystem. As a result the radionuclides are redistributed and buried in soil or lake bottom sediments. Estimation models for the radio-capacity of water and terrestrial ecosystems are represented. The calculations of the radio-capacity factor of water ecosystems are performed, and the high radio-capacity of a freshwater reservoir (F=0.6-0.8) and extremely high radio-capacity of a reservoir cascade (F c =0.99) is shown material from the Dnieper's cascade reservoirs. The methods of radio-capacity estimation of agroecosystems, wood and marine ecosystems are developed. (authors)

  16. 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....

  17. The Breakthrough Listen Search for Intelligent Life: 1.1-1.9 GHz Observations of 692 Nearby Stars

    Science.gov (United States)

    Enriquez, J. Emilio; Siemion, Andrew; Foster, Griffin; Gajjar, Vishal; Hellbourg, Greg; Hickish, Jack; Isaacson, Howard; Price, Danny C.; Croft, Steve; DeBoer, David; Lebofsky, Matt; MacMahon, David H. E.; Werthimer, Dan

    2017-11-01

    We report on a search for engineered signals from a sample of 692 nearby stars using the Robert C. Byrd Green Bank Telescope, undertaken as part of the Breakthrough Listen Initiative search for extraterrestrial intelligence. Observations were made over 1.1-1.9 GHz (L band), with three sets of five-minute observations of the 692 primary targets, interspersed with five-minute observations of secondary targets. By comparing the “ON” and “OFF” observations, we are able to identify terrestrial interference and place limits on the presence of engineered signals from putative extraterrestrial civilizations inhabiting the environs of the target stars. During the analysis, 11 events passed our thresholding algorithm, but a detailed analysis of their properties indicates that they are consistent with known examples of anthropogenic radio-frequency interference. We conclude that, at the time of our observations, none of the observed systems host high-duty-cycle radio transmitters emitting between 1.1 and 1.9 GHz with an Equivalent Isotropic Radiated Power of ˜1013 W, which is readily achievable by our own civilization. Our results suggest that fewer than ˜0.1% of the stellar systems within 50 pc possess the type of transmitters searched in this survey.

  18. 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.

  19. Die radio in Afrika

    Directory of Open Access Journals (Sweden)

    S. de Villiers

    1966-03-01

    Full Text Available Omvang van radio-uitsendings in en na Afrika. — Redes vir die versnelde tempo van uitbreiding. — Radio as die geskikste massa-kommunikasiemiddel vir Afrika. — Faktore wat die verspreiding bemoeilik. — Skouspelagtige toename in luistertalle.Toe Plinius, wat in die jaar 79 oorlede is, in sy „Historia Naturalis” verklaar het dat daar altyd iets nuuts uit Afrika afkomstig is, kon hy nouliks voorsien het dat die „iets" negentien eeue later in die lug sou setel wat hierdie reuse-vasteland oorspan — ’n Babelse spraakverwarring en ’n ongekende, verbete woorde-oorlog in die etergolwe, onder meer daarop bereken om die harte en hoofde van derduisendes te verower.

  20. Stations de radio confessionnelles

    OpenAIRE

    Chandès, Gérard

    2013-01-01

    L’auteur cherche à définir les propriétés sonores propres aux radios chrétiennes, principalement catholiques. La première partie de l’article se fonde sur l’étude historique des encycliques et des lettres pastorales du Vatican depuis l’inauguration de Radio Vatican et la seconde partie relève de la sémiologie du son. L’auteur cible les deux caractéristiques principales qui rendent compte de la relation à la transcendance divine : la prédilection pour les longues durées et des effets sonores t...

  1. Radio frequency ion source

    CERN Document Server

    Shen Guan Ren; Gao Fu; LiuNaiYi

    2001-01-01

    The study on Radio Frequency Ion Source is mainly introduced, which is used for CIAE 600kV ns Pulse Neutron Generator; and obtained result is also presented. The RF ion source consists of a diameter phi 25 mm, length 200 mm, coefficient of expansion =3.5 mA, beam current on target >=1.5 mA, beam spot =100 h.

  2. MUSIC RADIO-JOURNALISM

    OpenAIRE

    Dubovtceva Ludmila I.

    2014-01-01

    The article is based on years of practical experience, the author highlights the main radio genres in which music correspondent, music reviewer, music commentator, and music leading and a disc jockey work. Theoretical principles of their creative activities are analyzed in common journalistic genres, such as interview, reportage, talk show, live broadcast, radiofilm, as well as specialized genres like concert on demand and music competition. Journalist’ speech is seen as a logical element, th...

  3. Radio Frequency Interference Mitigation

    Science.gov (United States)

    An, T.; Chen, X.; Mohan, P.; Lao, B. Q.

    2017-09-01

    The observational facilities of radio astronomy keep constant upgrades and developments to achieve better capabilities including increasing the time of the data recording and frequency resolutions, and increasing the receiving and recording bandwidth. However in contrast, only a limited spectrum resource has been allocated to radio astronomy by the International Telecommunication Union, resulting in that the radio observational instrumentations are inevitably exposed to undesirable radio frequency interference (RFI) signals which originate mainly from the terrestrial human activity and are becoming stronger with time. RFIs degrade the quality of data and even lead to invalid data. The impact of RFIs on scientific outcome becomes more and more serious. In this article, the requirement for RFI mitigation is motivated, and the RFI characteristics, mitigation techniques, and strategies are reviewed. The mitigation strategies adopted at some representative observatories, telescopes, and arrays are also introduced. The advantages and shortcomings of the four classes of RFI mitigation strategies are discussed and presented, applicable at the connected causal stages: preventive, pre-detection, pre-correlation, and post-correlation. The proper identification and flagging of RFI is the key to the reduction of data loss and improvement in data quality, and is also the ultimate goal of developing RFI mitigation technique. This can be achieved through a strategy involving a combination of the discussed techniques in stages. The recent advances in the high speed digital signal processing and high performance computing allow for performing RFI excision of the large data volumes generated from large telescopes or arrays in both real time and offline modes, aiding the proposed strategy.

  4. Fast and flexible: argentine ants recruit from nearby trails.

    Directory of Open Access Journals (Sweden)

    Tatiana P Flanagan

    Full Text Available Argentine ants (Linepithema humile live in groups of nests connected by trails to each other and to stable food sources. In a field study, we investigated whether some ants recruit directly from established, persistent trails to food sources, thus accelerating food collection. Our results indicate that Argentine ants recruit nestmates to food directly from persistent trails, and that the exponential increase in the arrival rate of ants at baits is faster than would be possible if recruited ants traveled from distant nests. Once ants find a new food source, they walk back and forth between the bait and sometimes share food by trophallaxis with nestmates on the trail. Recruiting ants from nearby persistent trails creates a dynamic circuit, like those found in other distributed systems, which facilitates a quick response to changes in available resources.

  5. Gravitational interaction of a black hole with nearby matter

    International Nuclear Information System (INIS)

    Price, R.H.; Thorne, K.S.; Redmount, I.H.

    1986-01-01

    The interaction of a black hole with nearby matter is examined with a membrane paradigm which includes a 3+1 formalism that splits spacetime coordinates into a family of three-dimensional spacelike hypersurfaces and one-dimensional time. Emphasis is placed on the influence of matter and its gravity on the shape and evolution of the hole horizon and the effects of the hole on the matter. Universal time coordinates and fiduciary observers are defined outside a dynamically perturbed black hole and tidal gravitational fields are assumed to carry information on the disturbances. The exterior of the hole is examined in terms of the perturbed tidal fields and the material energy, momentum and stress which produce the perturbations. Finally, a membrane model is derived for the interaction of matter and its tidal fields with the stretched null horizon

  6. Radioactive Iron Rain: Evidence of a Nearby Supernova Explosion

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    A very close supernova explosion could have caused a mass extinction of life in Earth. In 1996, Brian Fields, the late Dave Schramm and the speaker proposed looking for unstable isotopes such as Iron 60 that could have been deposited by a recent nearby supernova explosion. A group from the Technical University of Munich has discovered Iron 60 in deep-ocean sediments and ferromanganese crusts due to one or more supernovae that exploded O(100) parsecs away about 2.5 million years ago. These results have recently been confirmed by a group from the Australian National University, and the Munich group has also discovered supernova Iron 60 in lunar rock samples. This talk will discuss the interpretation of these results in terms of supernova models, and the possible implications for life on Earth.

  7. PROBING EXTRAGALACTIC DUST THROUGH NEARBY GAMMA-RAY BURST AFTERGLOWS

    International Nuclear Information System (INIS)

    Liang, S. L.; Li Aigen

    2010-01-01

    The quantities and wavelength dependencies of the dust extinction along the lines of sight toward 33 nearby gamma-ray bursts (GRBs) with redshifts z V derived from the Drude approach is generally larger by a factor of ∼2-5 than that inferred by assuming a SMC-type template extinction law. Consistent with previous studies, the extinction-to-gas ratio is mostly smaller than that of the MW, and does not seem to correlate with the shape of the extinction curve. It is shown that the standard silicate-graphite interstellar grain model closely reproduces the extinction curves of all 33 GRBs host galaxies. For these 33 bursts at z < 2, we find no evidence for the evolution of the dust extinction, dust sizes, and relative abundances of silicate to graphite on redshifts.

  8. COMPANIONS TO NEARBY STARS WITH ASTROMETRIC ACCELERATION. II

    International Nuclear Information System (INIS)

    Tokovinin, Andrei; Hartung, Markus; Hayward, Thomas L.

    2013-01-01

    Hipparcos astrometric binaries were observed with the NICI adaptive optics system at Gemini-S, completing the work of Paper I. Among the 65 F, G, and K dwarfs within 67 pc of the Sun studied here, we resolve 18 new subarcsecond companions, remeasure 7 known astrometric pairs, and establish the physical nature of yet another 3 wider companions. The 107 astrometric binaries targeted at Gemini so far have 38 resolved companions with separations under 3''. Modeling shows that bright enough companions with separations on the order of an arcsecond can perturb the Hipparcos astrometry when they are not accounted for in the data reduction. However, the resulting bias of parallax and proper motion is generally below formal errors and such companions cannot produce fake acceleration. This work contributes to the multiplicity statistics of nearby dwarfs by bridging the gap between spectroscopic and visual binaries and by providing estimates of periods and mass ratios for many astrometric binaries.

  9. Candidate Nearby, Young Stars in Gaia's First Data Release

    Science.gov (United States)

    Chalifour, Matthieu; Kastner, Joel H.; Binks, Alex; Rodriguez, David; Punzi, Kristina; Zuckerman, Ben; Sacco, Germano

    2018-01-01

    The nearest examples of young stars are essential subjects for the study of planet and star formation. The recent data release from Gaia, which contains accurate parallax distances for ~2.5 million stars, allows age determinations via isochronal analysis for thousands of stars within ~100 pc. We have selected nearly 400 candidates nearby, young, late-type stars in the approximate mass range 0.5-1.0 Msun from the Tycho Gaia Astrometric Solution catalog on the basis of (a) D planets. We discuss our ongoing efforts to assess the accuracy of these stars' isochronal ages via various diagnostic tools, including galactic kinematics, UV excess, relative X-ray luminosity, andoptical spectroscopic indicators of youth.

  10. Negative and Positive Outflow-Feedback in Nearby (ULIRGs

    Directory of Open Access Journals (Sweden)

    Sara Cazzoli

    2017-12-01

    Full Text Available The starburst-AGN coexistence in local (ULIRGs makes these galaxies excellent laboratories for the study of stellar and AGN outflows and feedback. Outflows regulate star formation and AGN activity, redistributing gas, dust and metals over large scales in the interstellar and intergalactic media (negative feedback being also considered to be able to undergo vigorous star formation (positive feedback. In this contribution, I will summarize the results from a search for outflows in a sample of nearby 38 local (ULIRG systems observed with VIMOS/VLT integral field unit. For two galaxies of the sample I will detail the outflow properties and discuss the observational evidence for negative and positive outflow-feedback. The assessment of both negative and positive feedback effects represent a novel approach toward a comprehensive understanding of the impact of outflow feedback in the galaxy evolution.

  11. Radio frequency radiation (RFR) from TV and radio transmitters at a pilot region in Turkey

    International Nuclear Information System (INIS)

    Sirav, B.; Seyhan, N.

    2009-01-01

    For the last 30 y, the biological effects of non-ionising radiation (NIR: 0-300 GHz) have been a major topic in bio-electromagnetism. Since the number of radiofrequency (RF) systems operating in this frequency range has shown an incredible increase over the last few decades, the dangers of exposure to the fields generated thereby has become an important public health issue. In this study, the aim was to evaluate the level of RF electromagnetic radiation in Yenimahalle Sentepe Dededoruk Hill in Ankara (Turkey) that is a multiple-transmitter site hosting 64 different TV and radio towers and one base station for mobile phone communication. The site has been of interest as it is nearby a residential community. Within the technical input data available on 31 of the radio and TV transmitters, the calculated radiation level in this particular region was found to be approximately four times higher than the permitted standards of Turkey, which are the same as the ICNIRP standards. Electromagnetic field measurement is needed in the site. (authors)

  12. Radio frequency radiation (RFR) from TV and radio transmitters at a pilot region in Turkey.

    Science.gov (United States)

    Sirav, Bahriye; Seyhan, Nesrin

    2009-09-01

    For the last 30 y, the biological effects of non-ionising radiation (NIR: 0-300 GHz) have been a major topic in bioelectromagnetism. Since the number of radiofrequency (RF) systems operating in this frequency range has shown an incredible increase over the last few decades, the dangers of exposure to the fields generated thereby has become an important public health issue. In this study, the aim was to evaluate the level of RF electromagnetic radiation in Yenimahalle Sentepe Dededoruk Hill in Ankara, Turkey that is a multiple-transmitter site hosting 64 different TV and radio towers and one base station for mobile phone communication. The site has been of interest as it is nearby a residential community. Within the technical input data available on 31 of the radio and TV transmitters, the calculated radiation level in this particular region was found to be approximately four times higher than the permitted standards of Turkey, which are the same as the ICNIRP standards. Electromagnetic field measurement is needed in the site.

  13. Is the solar system entering a nearby interstellar cloud

    International Nuclear Information System (INIS)

    Vidal-Madjar, A.; Laurent, C.; Bruston, P.; Audouze, J.

    1978-01-01

    A model, based on different observations of the local interstellar medium, indicates the presence of a very close interstellar cloud in front of the Scorpius-Ophiuchus association (almost in the direction of the galactic center) approaching the solar system from a distance of about 0.03 pc at a velocity of about 15--20 km s -1 . These observations are as follows:1. The strong gradient of the hydrogen density in the interstellar medium deduced from current observations of this gas inside the solar system (n/sub H/approx.0.1 cm -3 ) and in front of many nearby stars in the anticenter direction (n/sub H/approx.0.01 cm -3 ).2. The anisotropy of the UV flux (around 950 A) from the brightest and closest O and B stars.3. The important variation of the deuterium to hydrogen ratio, which ranges from 2 x 10 -6 in the α Cen A direction to 4 x 10 -5 in the Aga Aur direction.A mechanism based on a selective radiation pressure effect that acts on deuterium atoms and not on hydrogen atoms explains satisfactorily the large spread in the deuterium abundance in the local interstellar medium. The operation of this mechanism requires that the geometrical configuration remain stable for approximately 10 7 years. This requirement implies the existence of a nearby interstellar cloud.Possible candidates do exist in the proper sky direction. One candidate, extensively discussed, presents a persistent interstellar absorption pattern over an angle of 40 0 related to a high column density, although covering only a few degrees in the sky, would lead to the same consequence. The presence of such condidates is not all contradicted by the interstellar reddening and absorption line observations.Other implications of the presence of such a close cloud are presented

  14. Urban solar irradiance and power prediction from nearby stations

    Directory of Open Access Journals (Sweden)

    Zihao Chen

    2017-06-01

    Full Text Available With the proliferation of small-scale solar PV installations, global horizontal irradiance (GHI and power predictions are becoming critical elements in the integration of PV generation into the grid. This paper considers short-term prediction, from 5 minutes to a few hours, based on historical meteorological measurement data from weather and power monitoring stations located in the Canberra (Australia region. The specific objective of this study is to produce skilful forecasts for (a generic target station using a minimal amount of observations from nearby stations. Thus, although a large number of weather and power variables are collected and used for developing and testing the prediction algorithms, the ultimate aim is to rely on a few predictors, mainly meteorologically based. This will allow the identification of critical instruments which would need to be installed in order to provide satisfactory PV power predictions while limiting capital and operating costs of monitoring. Relative mean absolute error (rMAE is used here to indicate prediction performance. Three statistical methods are tested for two different seasons, a winter and a summer. The relative importance of predictors and stations is assessed. A conversion from GHI to global irradiance on tilted surfaces, by means of simple geometry arguments and notion of irradiance components at a nearby site, is also introduced and tested. Finally, the prediction accuracy is categorised according to different clear-sky indices. Results show that when the clear-sky index exceeds 0.9 (near-to-cloudless conditions, the prediction performance is distinctly better than at lower clear sky indices, by at least 0.05 and 0.2 in terms of rMAE in summer and winter, respectively.

  15. Seasonal variations of ambient air mercury species nearby an airport

    Science.gov (United States)

    Fang, Guor-Cheng; Tsai, Kai-Hsiang; Huang, Chao-Yang; Yang, Kuang-Pu Ou; Xiao, You-Fu; Huang, Wen-Chuan; Zhuang, Yuan-Jie

    2018-04-01

    This study focuses on the collection of ambient air mercury species (total gaseous mercury (TGM), reactive gaseous mercury (RGM), gaseous element mercury (GEM) and particulate bound mercury (PBM) pollutants at airport nearby sampling site during the year of Apr. 2016 to Mar. 2017 by using Four-stage gold amalgamation and denuder. The results indicated that the average TGM, RGM and GEM concentrations were 5.04 ± 2.43 ng/m3, 29.58 ± 80.54 pg/m3, 4.70 ± 2.63 ng/m3, respectively during the year of Apr. 2016 to Mar. 2017 (n = 49) period at this airport sampling site nearby. In addition, the results also indicated that the average PBM concentrations in TSP and PM2.5 were 0.35 ± 0.08 ng/m3 and 0.09 ± 0.03 ng/m3, respectively. And the average PBM in TSP concentrations order follows as summer > autumn > spring > winter, while the average PBM in PM2.5 concentrations order follows as spring > summer > winter > autumn. Moreover, the average TGM, RGM and GEM concentrations order follow as spring > summer > autumn > winter. Finally, the Asian continent has the highest average mercury species concentrations (TGM, RGM, GEM and PBM) when compared with the American and European continents, and the average mercury species concentrations (TGM, RGM, GEM and PBM) displayed declined trends for North America (United States and Canada) and Europe (Spain, Sweden and Southern Baltic) during the years of 2004-2014. Also noteworthy is that the average mercury species concentrations (TGM, RGM, GEM) displayed increasing trends in China and Taiwan during the years of 2008-2016. Japan and Korea are the only two exceptions. Those above two countries mercury species concentrations displayed decreasing trends during years of 2008-2015.

  16. Evidence of genetic instability in tumors and normal nearby tissues.

    Directory of Open Access Journals (Sweden)

    Giuseppe Geraci

    Full Text Available BACKGROUND: Comprehensive analyses have recently been performed on many human cancer tissues, leading to the identification of a number of mutated genes but providing no information on the variety of mutations present in each of them. This information is of interest to understand the possible origin of gene mutations that cause tumors. METHODOLOGY/PRINCIPAL FINDINGS: We have analyzed the sequence heterogeneity of the transcripts of the human HPRT and G6PD single copy genes that are not considered tumor markers. Analyses have been performed on different colon cancers and on the nearby histologically normal tissues of two male patients. Several copies of each cDNA, which were produced by cloning the RT-PCR-amplified fragments of the specific mRNA, have been sequenced. Similar analyses have been performed on blood samples of two ostensibly healthy males as reference controls. The sequence heterogeneity of the HPRT and G6PD genes was also determined on DNA from tumor tissues. The employed analytical approach revealed the presence of low-frequency mutations not detectable by other procedures. The results show that genetic heterogeneity is detectable in HPRT and G6PD transcripts in both tumors and nearby healthy tissues of the two studied colon tumors. Similar frequencies of mutations are observed in patient genomic DNA, indicating that mutations have a somatic origin. HPRT transcripts show genetic heterogeneity also in healthy individuals, in agreement with previous results on human T-cells, while G6PD transcript heterogeneity is a characteristic of the patient tissues. Interestingly, data on TP53 show little, if any, heterogeneity in the same tissues. CONCLUSIONS/SIGNIFICANCE: These findings show that genetic heterogeneity is a peculiarity not only of cancer cells but also of the normal tissue where a tumor arises.

  17. A New Set of Nearby SNe Ia Lightcurves

    Science.gov (United States)

    Regnault, N.; Aldering, G.; Blanc, G.; Conley, A.; Dahlen, T.; Deustua, S.; Ellis, R.; Fan, X.; Folatelli, G.; Frye, B.; Garavini, G.; Gates, E.; Goldhaber, G.; Goldman, B.; Goobar, A.; Groom, D.; Hardin, D.; Hook, I.; Kent, S.; Kim, A.; Kim, M.; Knop, R.; Lidman, C.; Mendez, J.; Miller, G.; Moniez, M.; Mourao, A.; Newberg, H.; Nobili, S.; Nugent, P.; Pain, R.; Perdereau, O.; Perlmutter, S.; Quimby, R.; Rich, J.; Richards, G.; Ruiz-Lapuente, P.; Schaefer, B.; Walton, N.; Supernova Cosmology Project Collaboration

    2001-12-01

    Type Ia supernovae (SNe Ia) are powerful cosmological distance indicators and have been used for measuring cosmological parameters such as the Hubble constant, H0, and the mass density Ω m and dark energy density Ω Λ of the universe. These measurements rely on empirical correlations between absolute peak luminosities and other observables, like the postmaximum decline rate, and the color at maximum. Since the total number of well observed nearby Hubble flow SNe Ia is still small, these correlations are not yet fully characterized. In the Spring of 1999 the Supernova Cosmology Project undertook a nearby SN Ia search in collaboration with groups around the world. This campaign was aimed at providing an independent set of high quality light curves and spectra, to further study SN Ia properties, and fill the Hubble diagram at low redshift. 37 SNe were discovered, of which 19 were SNe Ia near or before maximum light, in the redshift range z=0.002 -- 0.15. These supernovae were followed-up photometrically and spectroscopically, using 20 different telescopes with apertures from 1-m to 10-m. We present the results of the very successful photometric follow-up. An average of 10 points was collected for each SN Ia in the B, V, R and I bands. In addition, we were able to obtain 5 well measured U-lightcurves. With this dataset, we are studying the correlations between the magnitude at maximum, the decline rate and the color at maximum. These systematic studies play a key role in the cosmological measurements using high redshift SNe Ia.

  18. Surveying the Dynamic Radio Sky with the Long Wavelength Demonstrator Array

    Science.gov (United States)

    2010-10-01

    been observed from brown dwarfs (Hallinan et al. 2007) and formerly radio- quiet magnetars (Camilo et al. 2006); single or highly intermittent pulses...magnetar flares or gi- ant pulses from pulsars in other galaxies (e.g., McLaughlin & Cordes 2003), prompt emission from GRBs (Usov & Katz 2000; Sagiv...expected from a nearby low-mass star, brown dwarf , or planet (§5). In practice, the local density of sources may be suffi- ciently low that there are no

  19. LOFAR/H-ATLAS: the low-frequency radio luminosity-star formation rate relation

    Science.gov (United States)

    Gürkan, G.; Hardcastle, M. J.; Smith, D. J. B.; Best, P. N.; Bourne, N.; Calistro-Rivera, G.; Heald, G.; Jarvis, M. J.; Prandoni, I.; Röttgering, H. J. A.; Sabater, J.; Shimwell, T.; Tasse, C.; Williams, W. L.

    2018-04-01

    Radio emission is a key indicator of star formation activity in galaxies, but the radio luminosity-star formation relation has to date been studied almost exclusively at frequencies of 1.4 GHz or above. At lower radio frequencies, the effects of thermal radio emission are greatly reduced, and so we would expect the radio emission observed to be completely dominated by synchrotron radiation from supernova-generated cosmic rays. As part of the LOFAR Surveys Key Science project, the Herschel-ATLAS NGP field has been surveyed with LOFAR at an effective frequency of 150 MHz. We select a sample from the MPA-JHU catalogue of Sloan Digital Sky Survey galaxies in this area: the combination of Herschel, optical and mid-infrared data enable us to derive star formation rates (SFRs) for our sources using spectral energy distribution fitting, allowing a detailed study of the low-frequency radio luminosity-star formation relation in the nearby Universe. For those objects selected as star-forming galaxies (SFGs) using optical emission line diagnostics, we find a tight relationship between the 150 MHz radio luminosity (L150) and SFR. Interestingly, we find that a single power-law relationship between L150 and SFR is not a good description of all SFGs: a broken power-law model provides a better fit. This may indicate an additional mechanism for the generation of radio-emitting cosmic rays. Also, at given SFR, the radio luminosity depends on the stellar mass of the galaxy. Objects that were not classified as SFGs have higher 150-MHz radio luminosity than would be expected given their SFR, implying an important role for low-level active galactic nucleus activity.

  20. 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 ...

  1. Dust and Molecular Gas in the Winds of Nearby Galaxies

    Science.gov (United States)

    McCormick, Alexander N.

    2015-04-01

    Galactic winds provide a fundamental mechanism for galaxy evolution. The outflow of material in winds remains the most likely culprit responsible for a host of galaxy observations, plus mounting evidence for galactic winds at times in the past points to their importance in understanding the history of the universe. Therefore, detailed observations of galactic winds are critical to fleshing out the narrative of galaxy evolution. In particular, the dust and molecular gas of a galaxy's interstellar medium (ISM) play crucial roles in the absorption, scattering, and reemission of starlight, the heating of the ISM, and provide critical materials for star formation. We present results from archival Spitzer Space Telescope ata and exceptionally deep Herschel Space Observatory data of the dust and molecular gas found in and around 20 nearby galaxies known to host galactic-scale winds. Selecting nearby galaxies has allowed us the resolution and sensitivity to differentiate dust and molecular gas outside the galaxies and observe their typically faint emission. These are the most detailed surveys currently available of the faint dust and molecular gas components in galactic winds, and we have utilized them to address the following questions: i) What are the location and morphology of dust and molecular gas, and how do these components compare with better known neutral and ionized gas features? ii) How much do dust and molecular gas contribute to the mass and energy of galactic winds? iii) Do the properties of the dust and molecular gas correlate with the properties of the wind-hosting galaxy? Spitzer archival data has revealed kiloparsec-scale polycyclic aromatic hydrocarbon (PAH) structures in the extraplanar regions of nearly all the wind-hosting galaxies we investigated. We found a nearly linear correlation between the extraplanar PAH emission and the total infrared flux, a proxy for star formation. Our results also suggest a correlation between the height of extraplanar

  2. The properties of radio ellipticals

    International Nuclear Information System (INIS)

    Sparks, W.B.; Disney, M.J.; Rodgers, A.W.

    1984-01-01

    Optical and additional radio data are presented for the bright galaxies of the Disney and Wall survey (1977 Mon. Not. R. Astron. Soc. 179, 235). These data form the basis of a statistical comparison of the properties of radio elliptical galaxies to radio-quiet ellipticals. The correlations may be explained by the depth of the gravitational potential well in which the galaxy resides governing the circumstances under which an elliptical galaxy rids itself of internally produced gas. (author)

  3. Jets, Arcs and Shocks: NGC 5195 at radio wavelengths

    Science.gov (United States)

    Rampadarath, H.; Soria, R.; Urquhart, R.; Argo, M. K.; Brightman, M.; Lacey, C. K.; Schlegel, E. M.; Beswick, R. J.; Baldi, R. D.; Muxlow, T. W. B.; McHardy, I. M.; Williams, D. R. A.; Dumas, G.

    2018-02-01

    We studied the nearby, interacting galaxy NGC 5195 (M 51b) in the radio, optical and X-ray bands. We mapped the extended, low-surface-brightness features of its radio-continuum emission; determined the energy content of its complex structure of shock-ionized gas; constrained the current activity level of its supermassive nuclear black hole. In particular, we combined data from the European Very Long Baseline Interferometry Network (˜1-pc scale), from our new e-MERLIN observations (˜10-pc scale), and from the Very Large Array (˜100-1000-pc scale), to obtain a global picture of energy injection in this galaxy. We put an upper limit to the luminosity of the (undetected) flat-spectrum radio core. We find steep-spectrum, extended emission within 10 pc of the nuclear position, consistent with optically-thin synchrotron emission from nuclear star formation or from an outflow powered by an active galactic nucleus (AGN). A linear spur of radio emission juts out of the nuclear source towards the kpc-scale arcs (detected in radio, Hα and X-ray bands). From the size, shock velocity, and Balmer line luminosity of the kpc-scale bubble, we estimate that it was inflated by a long-term-average mechanical power ˜3-6 × 1041 erg s-1 over the last 3-6 Myr. This is an order of magnitude more power than can be provided by the current level of star formation, and by the current accretion power of the supermassive black hole. We argue that a jet-inflated bubble scenario associated with previous episodes of AGN activity is the most likely explanation for the kpc-scale structures.

  4. Tectonic tremor activity associated with teleseismic and nearby earthquakes

    Science.gov (United States)

    Chao, K.; Obara, K.; Peng, Z.; Pu, H. C.; Frank, W.; Prieto, G. A.; Wech, A.; Hsu, Y. J.; Yu, C.; Van der Lee, S.; Apley, D. W.

    2016-12-01

    Tectonic tremor is an extremely stress-sensitive seismic phenomenon located in the brittle-ductile transition section of a fault. To better understand the stress interaction between tremor and earthquake, we conduct the following studies: (1) search for triggered tremor globally, (2) examine ambient tremor activities associated with distant earthquakes, and (3) quantify the temporal variation of ambient tremor activity before and after nearby earthquakes. First, we developed a Matlab toolbox to enhance the searching of triggered tremor globally. We have discovered new tremor sources in the inland faults in Kyushu, Kanto, and Hokkaido in Japan, southern Chile, Ecuador, and central Colombia in South America, and in South Italy. Our findings suggest that tremor is more common than previously believed and indicate the potential existence of ambient tremor in the triggered tremor active regions. Second, we adapt the statistical analysis to examine whether the long-term ambient tremor rate may affect by the dynamic stress of teleseismic earthquakes. We analyzed the data in Nankai, Hokkaido, Cascadia, and Taiwan. Our preliminary results did not show an apparent increase of ambient tremor rate after the passing of surface waves. Third, we quantify temporal changes in ambient tremor activity before and after the occurrence of local earthquakes under the southern Central Range of Taiwan with magnitudes of >=5.5 from 2004 to 2016. For a particular case, we found a temporal variation of tremor rate before and after the 2010/03/04 Mw6.3 earthquake, located about 20 km away from the active tremor source. The long-term increase in the tremor rate after the earthquake could have been caused by an increase in static stress following the mainshock. For comparison, clear evidence from seismic and GPS observations indicate a short-term increase in the tremor rate a few weeks before the mainshock. The increase in the tremor rate before the mainshock could correlate with stress changes

  5. UVES Abundances of Stars in Nearby Dwarf Spheroidal Galaxies

    Science.gov (United States)

    Tolstoy, Eline; Venn, Kim; Shetrone, Matt; Primas, Francesca; Hill, Vanessa; Kaufer, Andreas; Szeifert, Thomas

    2002-07-01

    It is a truth universally acknowledged, that a galaxy in possession of a good quantity of gas must want to form stars. It is the details of how and why that baffle us all. The simplest theories either would have this process a carefully self-regulated affair, or one that goes completely out of control and is capable of wrecking the galaxy which hosts it. Of course the majority of galaxies seem to amble along somewhere between these two extremes, and the mean properties tend to favour a quiescent self-regulated evolutionary scenario. But there area variety of observations which require us to invoke transitory ‘bursts’ of star-formation at one time or another in most galaxy types. Several nearby dwarf spheroidal galaxies have clearly determined star-formation histories with apparent periods of zero star formation followed by periods of fairly active star formation. If we are able to understand what separated these bursts we would understand several important phenomena in galaxy evolution. Were these galaxies able to clear out their gas reservoir in a burst of star formation? How did this gas return? or did it? Have these galaxies receieved gas from the IGM instead? Could stars from these types of galaxy contribute significantly to the halo population in our Galaxy? To answer these questions we need to combine accurate stellar photometry and Colour-Magnitude Diagram interpretation with detailed metal abundances to combine a star-formation rate versus time with a range of element abundances with time. Different elements trace different evolutionary process (e.g., relative contributions of type I and II supernovae). We often aren't even sure of the abundance spread in these galaxies. We have collected detailed high resolution UVES spectra of four nearby dwarf spheroidal galaxies (Sculptor, Fornax, Leo I & Carina) to begin to answer these questions. This is a precursor study to a more complete study with FLAMES. We presented at this meeting the initial results for

  6. Military Mail Radio

    Directory of Open Access Journals (Sweden)

    Bîlbîie Răduţ

    2015-12-01

    Full Text Available Cultural and scientific personalities from the army, military experts and creators of the doctrine have collaborated with the radio from the beginnings of radiophony, the educational role of this new, persuasive communication channel being evident not only for Romania or the Romanian army but also for all the countries that had radiophony services. This happens in the context of the end of the crisis and the start of economic and social development, promoting culture, creating a solid class of peasants with a certain social status, in villages, together with the priest, teacher and gendarme, increasing of the number of subscriptions and development of the Romanian radiophony.

  7. Radio frequency pulse compression

    International Nuclear Information System (INIS)

    Farkas, Z.D.

    1988-12-01

    High gradients require peak powers. One possible way to generate high peak powers is to generate a relatively long pulse at a relatively low power and compress it into a shorter pulse with higher peak power. It is possible to compress before dc to rf conversion as is done for the relativistic klystron or after dc to rf conversion as is done with SLED. In this note only radio frequency pulse compression (RFPC) is considered. Three methods of RFPC will be discussed: SLED, BEC, and REC. 3 refs., 8 figs., 1 tab

  8. La radio digital.

    OpenAIRE

    Cortés, Carlos

    2005-01-01

    La radio digital es un producto de la llamada convergencia digital. Desde la década de1990, nuevos dispositivos electrónicos de recepción y reproducción digital, incluyendo ciertos teléfonos celulares, se comunican entre sí, en los entornos de redes, mediante sencillas interfaces. Por esta razón, ofrecen ventajas antes inexistentes en los medios analógicos. A partir de sistemas de adquisición y producción digital, que comenzaron como simples cintas de audio digital (DAT), la evolución tec...

  9. Central radio sources

    International Nuclear Information System (INIS)

    Phinney, E.S.

    1985-01-01

    The compact radio sources in the nuclei of most active galaxies lie closer to their centers of activity than any other region accessible to observation, excepting only the broad emission line region. They provide uniquely strong evidence for bulk motion of matter at relativistic velocities, encouraging the belief that the activity originates in a gravitational potential well whose escape velocity is of the order of the speed of light. The observational facts are reviewed as well as several theoretical pictures of them. Those places where systematic observations could help to distinguish the true theoretical picture from the many competing forgeries are emphasized. 76 references

  10. Pluralismo, radio e Internet

    OpenAIRE

    Bruce Girard

    2015-01-01

    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.

  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. 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...

  13. Imaging the Obscuring Torus in Nearby Active Galaxies

    Science.gov (United States)

    Wilson, Andrew S.; Storchi Bergmann, Thaisa; Morris, Simon

    2000-02-01

    We propose to study a sample of Seyfert galaxies with the aim of resolving spatially the torus of dense molecular gas and dust which is believed to surround the nuclei of these objects. The galaxies, selected to have strong molecular hydrogen emission and jet-like radio continuum sources, will be imaged in various molecular hydrogen lines and in [Fe II] or Br (gamma). The goals are to a) confirm the existence of such tori, b) determine whether the extended molecular gas is excited thermally or through fluorescence, and c) compare with the distribution of ionized gas, which may show an ionization cone structure from polar escape of ionizing photons. The availability of IR imaging capabilities with tip-tilt and narrow-band filters, which allow imaging in the H_2(lambda) 2.122(micron) line up to a recession velocity of 6,000 km s^-1, makes the Blanco 4m telescope very well suited to this project.

  14. Dating of two nearby ice cores from the Illimani, Bolivia

    Science.gov (United States)

    Knüsel, S.; Ginot, P.; Schotterer, U.; Schwikowski, M.; GäGgeler, H. W.; Francou, B.; Petit, J. R.; Simões, J. C.; Taupin, J. D.

    2003-03-01

    In order to establish a chronology of two nearby ice cores from a glacier at Illimani (6438 m), Bolivia, a broad dating approach is presented here, which in particular makes use of the fast, simple, and nearly nondestructive electrical conductivity method (ECM) that provides a highly resolved record. Thus, ECM is suited for counting annual layers in the ice, especially for ice cores extracted from high-mountain glaciers with a fast layer thinning. Furthermore, ECM can be used for detecting volcanic signals. Annual signals in the ECM record of the Illimani ice core were identified using the 1964 A.D. tritium reference horizon and were counted along 125 m or 90% of the core, representing the time period from 1200 ± 240 A.D. (estimated accumulated error) to 1999 A.D. The resulting age-depth relationship was supported by counting annual peaks in the microparticle record as well as by nuclear dating using the decay of 210Pb. The identification of volcanic signals originating from eruptions such as Pinatubo (1991 A.D.), El Chichón (1982 A.D.), Agung (1963 A.D.), Krakatoa (1883 A.D.), Tambora (1815 A.D.), and the Unknown 1258 A.D. significantly reduced the uncertainty of annual layer counting (ALC) to ±2 years in the vicinity of these events.

  15. Do landfills affect the environmental quality of nearby streams?

    Directory of Open Access Journals (Sweden)

    Leandro Schlemmer Brasil

    2017-12-01

    Full Text Available When inappropriately disposed, solid waste may contaminate the soil, water and air, leading to severe negative impacts on biodiversity. The Brazilian National Policy for Solid Waste (PNRS requires municipalities to ensure the environmental quality of landfills. Accordingly, our objective was to evaluate the community of aquatic insects in a stream with stretches downstream and upstream of a sanitary landfill. Our hypothesis was that there will be no differences in insect community between the stretches (downstream and upstream on the basis of the premise that landfills abiding by the PNRS do not cause environmental damage to nearby areas. There was no change in any aspect of the composition of the macroinvertebrate community as a result of the landfill. The only changes observed in the macroinvertebrate communities occurred between the dry and rainy seasons, which were related to the seasonality and consequent changes in the environmental conditions of the water over the year. Our study, although limited, showed primary and pioneering evidence that the PNRS can contribute positively to the conservation of the biotic quality of aquatic environments, further reinforcing the need for immediate implementation of the PNRS throughout the country.

  16. Radioactivity of seawater nearby Daya Bay Nuclear Power Station

    Science.gov (United States)

    Deng, F.; Lin, Q.; Zhou, R. D.; Chen, W. L.; Chen, Z. D.

    2017-08-01

    The radioactivity of seawater nearby Daya Bay NPPs was introduced in this paper. The average annual concentrations of 90Sr and 137Cs ranged from 0.55∼2.38 and 0.81∼4.68 Bq·m-3 respectively during 1993∼2015. The average annual concentration range of 3H is 0.8∼7 Bq·L-1. The concentration range of 14C is 7.6—8.6 Bq·m-3, and the concentration of 3H and 14C is higher than that of the reference location or the background, but with no cumulative effect. The concentrations of 90Sr and 137Cs in seawater have no obvious relationship with the nuclear liquid effluent discharging. The average concentrations of 238U and 232Th were 24.6±10.6 and 18.1±7.5 Bq·m-3 respectively during 2000∼2008.

  17. Could a nearby supernova explosion have caused a mass extinction?

    CERN Document Server

    Ellis, Jonathan Richard

    1995-01-01

    We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by palaeontologists. We discuss the likely rate of such events in the light of the recent identification of Geminga as a supernova remnant less than 100 pc away and the discovery of a millisecond pulsar about 150 pc away, and observations of SN 1987A. The fluxes of $\\gamma$ radiation and charged cosmic rays on the Earth are estimated, and their effects on the Earth's ozone layer discussed. A supernova explosion of the order of 10 pc away could be expected every few hundred million years, and could destroy the ozone layer for hundreds of years, letting in potentially lethal solar ultraviolet radiation. In addition to effects on land ecology, this could entail mass destruction of plankton and reef communities, with disastrous consequences for marine life as well. A supernova extinction should be distinguishable from a meteorite impact such as the one that presumably killed the dinosaurs.

  18. Could a nearby supernova explosion have caused a mass extinction?

    Science.gov (United States)

    Ellis, J; Schramm, D N

    1995-01-03

    We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by paleontologists. We discuss the possible rate of such events in the light of the recent suggested identification of Geminga as a supernova remnant less than 100 parsec (pc) away and the discovery of a millisecond pulsar about 150 pc away and observations of SN 1987A. The fluxes of gamma-radiation and charged cosmic rays on the Earth are estimated, and their effects on the Earth's ozone layer are discussed. A supernova explosion of the order of 10 pc away could be expected as often as every few hundred million years and could destroy the ozone layer for hundreds of years, letting in potentially lethal solar ultraviolet radiation. In addition to effects on land ecology, this could entail mass destruction of plankton and reef communities, with disastrous consequences for marine life as well. A supernova extinction should be distinguishable from a meteorite impact such as the one that presumably killed the dinosaurs at the "KT boundary." The recent argument that the KT event was exceedingly large and thus quite rare supports the need for other catastrophic events.

  19. Could a nearby supernova explosion have caused a mass extinction?

    International Nuclear Information System (INIS)

    Ellis, J.; Schramm, D.N.

    1995-01-01

    We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by paleontologists. We discuss the possible rate of such events in the light of the recent suggested identification of Geminga as a supernova remnant less than 100 parsec (pc) away and the discovery of a millisecond pulsar about 150 pc away and observations of SN 1987A. The fluxes of γ-radiation and charged cosmic rays on the Earth are estimated, and their effects on the Earth's ozone layer are discussed. A supernova explosion of the order of 10 pc away could be expected as often as every few hundred million years and could destroy the ozone layer for hundreds of years, letting in potentially lethal solar ultraviolet radiation. In addition to effects on land ecology, this could entail mass destruction of plankton and reef communities, with disastrous consequences for marine life as well. A supernova extinction should be distinguishable from a meteorite impact such as the one that presumably killed the dinosaurs at the open-quotes KT boundary.close quotes The recent argument that the KT event was exceedingly large and thus quite rare supports the need for other catastrophic events. 24 refs

  20. EVIDENCE FOR ACCRETION IN A NEARBY, YOUNG BROWN DWARF

    International Nuclear Information System (INIS)

    Reiners, Ansgar

    2009-01-01

    We report on the discovery of the young, nearby, brown dwarf 2MASS J0041353-562112. The object has a spectral type of M7.5; it shows Li absorption and signatures of accretion, which implies that it still has a disk and suggests an age below 10 Myr. The space motion vector and position on the sky indicate that the brown dwarf is probably a member of the ∼20 Myr old Tuc-Hor association, or that it may be an ejected member of the ∼12 Myr old β Pic association; both would imply that 2MASS J0041353-562112 may in fact be older than 10 Myr. No accreting star or brown dwarf was previously known in these associations. Assuming an age of 10 Myr, the brown dwarf has a mass of about 30 M Jup and is located at 35 pc distance. The newly discovered object is the closest accreting brown dwarf known. Its membership to an association older than 10 Myr implies that either disks in brown dwarfs can survive as long as in more massive stars, perhaps even longer, or that star formation in Tuc-Hor or β Pic occurred more recently than previously thought. The history and evolution of this object can provide new fundamental insight into the formation process of stars, brown dwarfs, and planets.

  1. Low-mass Visual Companions to Nearby G-dwarfs

    Science.gov (United States)

    Tokovinin, Andrei

    2011-02-01

    A complete census of wide visual companions to nearby G-dwarf stars can be achieved by selecting candidates from the Two Micron All Sky Survey (2MASS) Point-Source Catalog and checking their status by second-epoch imaging. Such data are obtained for 124 candidates with separations up to 20'', 47 of which are shown to be new physical low-mass stellar companions. A list of visual binaries with G-dwarf primaries is produced by combining newly found companions with historical data. Maximum likelihood analysis leads to a companion frequency of 0.13 ± 0.015 per decade of separation. The mass ratio is distributed almost uniformly, with a power-law index between -0.4 and 0. The remaining uncertainty in the index is related to modeling of the companion detection threshold in 2MASS. These findings are confirmed by an alternative analysis of wider companions in 2MASS, removing the contamination by background stars statistically. Extension of this work will lead to a complete detection of visual companions—a necessary step toward reaching unbiased multiplicity statistics over the full range of orbital periods and, eventually, understanding the origin of multiple systems.

  2. Identifying New Nearby White Dwarfs in the Southern Hemisphere

    Science.gov (United States)

    Subasavage, John P.; Lepine, Sebastien

    2011-08-01

    We propose to use the SMARTS 1.0m Y4KCam and the Goodman Spectrograph at SOAR to spectroscopically confirm nearby white dwarfs (WDs) in the solar neighborhood. By utilizing an extensive list of high proper motion targets from the proprietary SUPERBLINK database in the southern hemisphere, we have identified ~600 candidate WD systems. Using photometric distance relations, we estimate that ~160 are within 40 pc, including ~30 that are within the NStars horizon of interest, 25 pc. Upon spectroscopic confirmation, we intend to select targets estimated to be within 25 pc to be added to the CTIO Parallax Investigation (CTIOPI) to obtain trigonometric parallaxes and ensure sample membership. From these data, we continue to push toward a complete volume-limited sample of WDs that we can evaluate for myriad distributions (e.g., chemical, multiplicity, velocity) and reliably extrapolate to much larger spatial scales within our Galaxy. We are particularly interested in identifying WDs with metal contamination for additional followup.

  3. [Nearby nature as a moderator of stress during childhood].

    Science.gov (United States)

    Corraliza, José Antonio; Collado, Silvia

    2011-04-01

    The aim of this investigation is to study the relation between the amount of nature existing in children's daily environments and the way children deal with stressful events. Every day, children are exposed to situations that cause stress. Taking into account previous studies, it is thought that the greener the place where children spend their time, the better they cope with adversities. Thus, when comparing the stress level of children who are exposed to the same amount of adverse situations, the children who have more frequent daily contact with nature will show less stress than those who do not spend time in nature. This effect from nearby nature is called a buffering effect. The present study provides empirical evidence of the buffering effect caused by the existence of Nature in the residential and the school environment. Therefore, our results show that children who have more access to nature increase their resilience, showing a lower stress level than children whose contact with nature is less frequent.

  4. Radiation-Induced Correlation between Molecules Nearby Metallic Antenna Array

    Directory of Open Access Journals (Sweden)

    Yoshiki Osaka

    2015-01-01

    Full Text Available We theoretically investigate optical absorption of molecules embedded nearby metallic antennas by using discrete dipole approximation method. It is found that the spectral peak of the absorption is shifted due to the radiation-induced correlation between the molecules. The most distinguishing feature of our work is to show that the shift is largely enhanced even when the individual molecules couple with localized surface plasmons near the different antennas. Specifically, we first consider the case that two sets of dimeric gold blocks with a spacing of a few nanometers are arranged and reveal that the intensity and spectral peak of the optical absorption strongly depend on the position of the molecules. In addition, when the dimeric blocks and the molecules are periodically arranged, the peak shift is found to increase up to ~1.2 meV (300 GHz. Because the radiation-induced correlation is essential for collective photon emission, our result implies the possibility of plasmon-assisted superfluorescence in designed antenna-molecule complex systems.

  5. The POKEMON Speckle Survey of Nearby M-Dwarfs

    Science.gov (United States)

    van Belle, Gerard; von Braun, Kaspar; Horch, Elliott; Clark, Catherine; DSSI Speckle Team

    2018-01-01

    The POKEMON (Pervasive Overview of Kompanions of Every M-dwarf in Our Neighborhood) survey of nearby M-dwarfs intends to inspect, at diffraction-limited resolution, every low-mass star out to 15pc, along with selected additional objects to 25pc. The primary emphasis of the survey is detection of low-mass companions to these M-dwarfs for refinement of the low-mass star multiplicity rate. The resultant catalog of M-dwarf companions will also guide immediate refinement of transit planet detection results from surveys such as TESS. POKEMON is using Lowell Observatory's 4.3-m Discovery Channel Telescope (DCT) with the Differential Speckle Survey Instrument (DSSI) speckle camera, along with the NN-Explore Exoplanet Stellar Speckle Imager (NESSI) speckle imager on 3.5-m WIYN; the survey takes advantage of the extremely rapid observing cadence rates possible with WIYN and (especially) DCT. The current status and preliminary results from the first 20+ nights of observing will be presented. Gotta observe them all!

  6. 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

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

    Indian Academy of Sciences (India)

    of light into its constituent colours (or wavelengths, since light of different colours corresponds to light of different wavelengths) is called a ... together to form neutral atoms). The diffuse gas that is found between stars is also a strong emitter of radio-waves. In general, optical telescopes show us where stars are, while radio.

  8. 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.

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

    Indian Academy of Sciences (India)

    background, listening intently to this extra-terrestrial signal. For many people of that generation, this is likely to have been their first, and most likely only, exposure to radio astronomy. In some ways, however, what is more surprising is that the general public has some exposure to radio astronomy at all, let alone through a.

  10. 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.

  11. 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.

  12. 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,

  13. 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

  14. 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...... presented along the paper are useful for future radio network planning considerations....

  15. RADIO NOISE ADVANCES SEXUAL MATURITY

    African Journals Online (AJOL)

    ansistf-lewis

    groups for a regression of body weight on age at first egg, indicating that accelerated growth did not contribute to the advance in ... clocks that operated the radios and the lights. The other two chambers ... Mean body weight at first egg for the birds given the radio noise was not significantly different from the controls (Table).

  16. 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

  17. THE GREEN BANK TELESCOPE MAPS THE DENSE, STAR-FORMING GAS IN THE NEARBY STARBURST GALAXY M82

    Energy Technology Data Exchange (ETDEWEB)

    Kepley, Amanda A.; Frayer, David [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944-0002 (United States); Leroy, Adam K. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Usero, Antonio [Observatorio Astronómico Nacional, C/Alfonso XII, 3, E-28014 Madrid (Spain); Marvil, Josh [Department of Physics, New Mexico Tech., 801 Leroy Place, Socorro, NM 87801 (United States); Walter, Fabian, E-mail: akepley@nrao.edu [Max Planck Institute fur Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)

    2014-01-01

    Observations of the Milky Way and nearby galaxies show that dense molecular gas correlates with recent star formation, suggesting that the formation of this gas phase may help regulate star formation. A key test of this idea requires wide-area, high-resolution maps of dense molecular gas in galaxies to explore how local physical conditions drive dense gas formation, but these observations have been limited because of the faintness of dense gas tracers like HCN and HCO{sup +}. Here we demonstrate the power of the Robert C. Byrd Green Bank Telescope (GBT)—the largest single-dish millimeter radio telescope—for mapping dense gas in galaxies by presenting the most sensitive maps yet of HCN and HCO{sup +} in the starburst galaxy M82. The HCN and HCO{sup +} in the disk of this galaxy correlates with both recent star formation and more diffuse molecular gas and shows kinematics consistent with a rotating torus. The HCO{sup +} emission extending to the north and south of the disk is coincident with the outflow previously identified in CO and traces the eastern edge of the hot outflowing gas. The central starburst region has a higher ratio of star formation to dense gas than the outer regions, pointing to the starburst as a key driver of this relationship. These results establish that the GBT can efficiently map the dense molecular gas at 90 GHz in nearby galaxies, a capability that will increase further with the 16 element feed array under construction.

  18. STAR FORMATION AND SUPERCLUSTER ENVIRONMENT OF 107 NEARBY GALAXY CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Seth A.; Hickox, Ryan C.; Wegner, Gary A. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); Einasto, Maret; Vennik, Jaan [Tartu Observatory, 61602 Tõravere (Estonia)

    2017-01-20

    We analyze the relationship between star formation (SF), substructure, and supercluster environment in a sample of 107 nearby galaxy clusters using data from the Sloan Digital Sky Survey. Previous works have investigated the relationships between SF and cluster substructure, and cluster substructure and supercluster environment, but definitive conclusions relating all three of these variables has remained elusive. We find an inverse relationship between cluster SF fraction ( f {sub SF}) and supercluster environment density, calculated using the Galaxy luminosity density field at a smoothing length of 8 h {sup −1} Mpc (D8). The slope of f {sub SF} versus D8 is −0.008 ± 0.002. The f {sub SF} of clusters located in low-density large-scale environments, 0.244 ± 0.011, is higher than for clusters located in high-density supercluster cores, 0.202 ± 0.014. We also divide superclusters, according to their morphology, into filament- and spider-type systems. The inverse relationship between cluster f {sub SF} and large-scale density is dominated by filament- rather than spider-type superclusters. In high-density cores of superclusters, we find a higher f {sub SF} in spider-type superclusters, 0.229 ± 0.016, than in filament-type superclusters, 0.166 ± 0.019. Using principal component analysis, we confirm these results and the direct correlation between cluster substructure and SF. These results indicate that cluster SF is affected by both the dynamical age of the cluster (younger systems exhibit higher amounts of SF); the large-scale density of the supercluster environment (high-density core regions exhibit lower amounts of SF); and supercluster morphology (spider-type superclusters exhibit higher amounts of SF at high densities).

  19. A Metagenomic Survey of Serpentinites and Nearby Soils in Taiwan

    Science.gov (United States)

    Li, K. Y.; Hsu, Y. W.; Chen, Y. W.; Huang, T. Y.; Shih, Y. J.; Chen, J. S.; Hsu, B. M.

    2016-12-01

    The serpentinite of Taiwan is originated from the subduction zone of the Eurasian plate and the Philippine Sea plate. Many small bodies of serpentinite are scattered around the lands of the East Rift Valley, which are also one of the major agricultural areas in Taiwan. Since microbial communities play a role both on weathering process and soil recovery, uncovering the microbial compositions in serpentinites and surrounding soils may help people to understand the roles of microorganisms on serpentinites during the nature weathering process. In this study, microorganisms growing on the surface of serpentinites, in the surrounding soil, and agriculture soils that are miles of horizontal distance away from serpentinite were collected. Next generation sequencing (NGS) was carried out to examine the metagenomics of uncultured microbial community in these samples. The metagenomics were further clustered into operational taxonomic units (OTUs) to analyze relative abundance, heatmap of OTUs, and principal coordinates analysis (PCoA). Our data revealed the different types of geographic material had their own distinct structures of microbial community. In serpentinites, the heatmaps based on the phylogenetic pattern showed that the OTUs distributions were similar in phyla of Bacteroidetes, Cyanobacteria, Proteobacteria, Verrucomicrobia, and WPS-1/WPS-2. On the other hand, the heatmaps of phylogenetic pattern of agriculture soils showed that the OTUs distributions in phyla of Chloroflexi, Acidobacteria, Actinobacteria, WPS-1/WPS-2, and Proteobacteria were similar. In soil nearby the serpentinite, some clusters of OTUs in phyla of Bacteroidetes, Cyanobacteria, and WPS-1/WPS-2 have disappeared. Our data provided evidence regarding kinetic evolutions of microbial communities in different geographic materials.

  20. Search for bright nearby M dwarfs with virtual observatory tools

    Energy Technology Data Exchange (ETDEWEB)

    Aberasturi, M.; Caballero, J. A.; Montesinos, B.; Gálvez-Ortiz, M. C.; Solano, E.; Martín, E. L. [Centro de Astrobiología (CSIC-INTA), Departamento de Astrofísica, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain)

    2014-08-01

    Using Virtual Observatory tools, we cross-matched the Carlsberg Meridian 14 and the 2MASS Point Source catalogs to select candidate nearby bright M dwarfs distributed over ∼25,000 deg{sup 2}. Here, we present reconnaissance low-resolution optical spectra for 27 candidates that were observed with the Intermediate Dispersion Spectrograph at the 2.5 m Isaac Newton Telescope (R≈ 1600). We derived spectral types from a new spectral index, R, which measures the ratio of fluxes at 7485-7015 Å and 7120-7150 Å. We also used VOSA, a Virtual Observatory tool for spectral energy distribution fitting, to derive effective temperatures and surface gravities for each candidate. The resulting 27 targets were M dwarfs brighter than J = 10.5 mag, 16 of which were completely new in the Northern hemisphere and 7 of which were located at less than 15 pc. For all of them, we also measured Hα and Na I pseudo-equivalent widths, determined photometric distances, and identified the most active stars. The targets with the weakest sodium absorption, namely, J0422+2439 (with X-ray and strong Hα emissions), J0435+2523, and J0439+2333, are new members in the young Taurus-Auriga star-forming region based on proper motion, spatial distribution, and location in the color-magnitude diagram, which reopens the discussion on the deficit of M2-4 Taurus stars. Finally, based on proper motion diagrams, we report on a new wide M dwarf binary system in the field, LSPM J0326+3929EW.

  1. Discovery of path nearby clusters in spatial networks

    KAUST Repository

    Shang, Shuo

    2015-06-01

    The discovery of regions of interest in large cities is an important challenge. We propose and investigate a novel query called the path nearby cluster (PNC) query that finds regions of potential interest (e.g., sightseeing places and commercial districts) with respect to a user-specified travel route. Given a set of spatial objects O (e.g., POIs, geo-tagged photos, or geo-tagged tweets) and a query route q , if a cluster c has high spatial-object density and is spatially close to q , it is returned by the query (a cluster is a circular region defined by a center and a radius). This query aims to bring important benefits to users in popular applications such as trip planning and location recommendation. Efficient computation of the PNC query faces two challenges: how to prune the search space during query processing, and how to identify clusters with high density effectively. To address these challenges, a novel collective search algorithm is developed. Conceptually, the search process is conducted in the spatial and density domains concurrently. In the spatial domain, network expansion is adopted, and a set of vertices are selected from the query route as expansion centers. In the density domain, clusters are sorted according to their density distributions and they are scanned from the maximum to the minimum. A pair of upper and lower bounds are defined to prune the search space in the two domains globally. The performance of the PNC query is studied in extensive experiments based on real and synthetic spatial data. © 2014 IEEE.

  2. A rocky planet transiting a nearby low-mass star.

    Science.gov (United States)

    Berta-Thompson, Zachory K; Irwin, Jonathan; Charbonneau, David; Newton, Elisabeth R; Dittmann, Jason A; Astudillo-Defru, Nicola; Bonfils, Xavier; Gillon, Michaël; Jehin, Emmanuël; Stark, Antony A; Stalder, Brian; Bouchy, Francois; Delfosse, Xavier; Forveille, Thierry; Lovis, Christophe; Mayor, Michel; Neves, Vasco; Pepe, Francesco; Santos, Nuno C; Udry, Stéphane; Wünsche, Anaël

    2015-11-12

    M-dwarf stars--hydrogen-burning stars that are smaller than 60 per cent of the size of the Sun--are the most common class of star in our Galaxy and outnumber Sun-like stars by a ratio of 12:1. Recent results have shown that M dwarfs host Earth-sized planets in great numbers: the average number of M-dwarf planets that are between 0.5 to 1.5 times the size of Earth is at least 1.4 per star. The nearest such planets known to transit their star are 39 parsecs away, too distant for detailed follow-up observations to measure the planetary masses or to study their atmospheres. Here we report observations of GJ 1132b, a planet with a size of 1.2 Earth radii that is transiting a small star 12 parsecs away. Our Doppler mass measurement of GJ 1132b yields a density consistent with an Earth-like bulk composition, similar to the compositions of the six known exoplanets with masses less than six times that of the Earth and precisely measured densities. Receiving 19 times more stellar radiation than the Earth, the planet is too hot to be habitable but is cool enough to support a substantial atmosphere, one that has probably been considerably depleted of hydrogen. Because the host star is nearby and only 21 per cent the radius of the Sun, existing and upcoming telescopes will be able to observe the composition and dynamics of the planetary atmosphere.

  3. From nearby to distant galaxies: kinematical and dynamical studies

    Science.gov (United States)

    Epinat, Benoit

    2009-09-01

    Kinematical studies of low and high redshift galaxies enables to probe galaxy formation and evolution scenarios. Integral field spectroscopy is a powerful tool to study with accuracy nearby galaxies kinematics. Recent observations also gives a new 2D vision of high redshift galaxies kinematics. This work mostly relies on the kinematical sample of galaxies GHASP. This control sample, composed of 203 local spiral and irregular galaxies in low density environments observed with Fabry-Perot techniques in the Ha line (6563 A), is by now the largest sample of Fabry-Perot data. After a revue on Fabry-Perot interferometry and a presentation of new data reduction procedures, my implications on both 3D-NTT Fabry-Perot instrument and the wide field spectrograph project (WFSpec) for galaxy evolution study with the european ELT are developed. The second section is dedicated to GHASP data. This sample have been fully reduced and analysed using new methods. The kinematical analysis of 2D kinematical maps has been undertaken with the study of the dark matter distribution, the rotation curves shape, bar signatures and the ionized gas velocity dispersion. In a third section, this local reference sample is used as a zero point for high redshift galaxies kinematical studies. The GHASP sample is projected at high redshift (z=1.7) in order to disentangle evolution effects from distance biases in high redshift galaxies kinematical data observed with SINFONI, OSIRIS and GIRAFFE. The kinematical analysis of new SINFONI high redshift observations is also presented and high redshift data found in the literature are compared with GHASP projected sample, suggesting some evolution of the galaxy dynamical support within the ages.

  4. THE NUCLEAR ACTIVITIES OF NEARBY S0 GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Meng-Yuan; Gu, Qiu-Sheng; Chen, Yan-Mei; Zhou, Luwenjia, E-mail: qsgu@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210093, P. R. China (China)

    2016-11-01

    We present a study of nuclear activities in nearby S0 galaxies. After cross-matching the Sloan Digital Sky Survey Data Release 7 with the Third Reference Catalog of Bright Galaxies (RC3) and visually checking the SDSS images, we derive a sample of 583 S0 galaxies with the central spectrophotometric information. In order to separate nebular emission lines from the underlying stellar contribution, we fit the stellar population model to the SDSS spectra of these S0 galaxies. According to the BPT diagram, we find that 8% of S0 galaxies show central star-forming activity, while the fractions of Seyfert, Composite, and low-ionization nuclear emission-line regions (LINERs) are 2%, 8%, and 21.4%, respectively. We also find that star-forming S0s have the lowest stellar masses, over one magnitude lower than the others, and that the active S0s are mainly located in the sparse environment, while the normal S0s are located in the dense environment, which might suggest that the environment plays an important role in quenching star formation and/or AGN activity in S0 galaxies. By performing bulge-disk decomposition of 45 star-forming S0s in g - and r -bands with the 2D fitting software Galfit, as well as exploiting the catalog of 2D photometric decompositions of Meert et al., we find that the bulges of approximately one-third of star-forming S0 galaxies (16/45) are bluer than their disks, while for other types of S0s the bulge and disk components show similar color distributions. Besides, the Sérsic index of most star-forming S0s bulges is less than two, while for normal S0s, it is between two and six.

  5. Health effects on nearby residents of a wood treatment plant

    International Nuclear Information System (INIS)

    Dahlgren, James; Warshaw, Raphael; Thornton, John; Anderson-Mahoney, P.M.; Takhar, Harpreet

    2003-01-01

    Objectives: The aim of the study was to evaluate the health status of nearby residents of a wood treatment plant who had sustained prolonged low-level environmental exposure to wood processing waste chemicals. Methods: A population of 1269 exposed residents who were plaintiffs or potential plaintiffs in a lawsuit against the wood treatment plant were evaluated by questionnaire for a health history and symptoms. A representative sample of 214 exposed subjects was included in the analysis. One hundred thirty-nine controls were selected from 479 unexposed volunteers and matched to the exposed subjects as closely as possible by gender and age. Subjects and controls completed additional questionnaires and were evaluated by a physician for medical history and physical examination, blood and urine testing, neurophysiological and neuropsychological studies, and respiratory testing. Environmental sampling for wood processing waste chemicals was carried out on soil and drainage ditch sediment in the exposed neighborhood. Results: The exposed subjects had significantly more cancer, respiratory, skin, and neurological health problems than the controls. The subjective responses on questionnaires and by physician histories revealed that the residents had a significantly greater prevalence of mucous membrane irritation, and skin and neurological symptoms, as well as cancer. (Exposed versus unexposed, cancer 10.0% versus 2.08%, bronchitis 17.8% versus 5.8%, and asthma by history 40.5% versus 11.0%) There were significantly more neurophysiologic abnormalities in adults of reaction time, trails A and B, and visual field defects. Conclusions: Adverse health effects were significantly more prevalent in long-term residents near a wood treatment plant than in controls. The results of this study suggest that plant emissions from wood treatment facilities should be reduced

  6. Biomonitoring a human population inhabiting nearby a deactivated uranium mine

    International Nuclear Information System (INIS)

    Lourenço, J.; Pereira, R.; Pinto, F.; Caetano, T.; Silva, A.; Carvalheiro, T.

    2013-01-01

    Highlights: ► Human population environmentally exposed to uranium mining wastes. ► Significantly higher levels of manganese and uranium in peripheral blood samples. ► Significant DNA damages detected by the comet assay. ► Significant decrease of NK and T lymphocytes counts in exposed individuals. ► Concerns on the risks of human populations living nearby uranium mining areas. - Abstract: Environmental exposure to uranium and its daughter radionuclides, has been linked to several negative effects such as those related with important physiological processes, like hematopoiesis, and may also be associated with genotoxicity effects. Herein, genotoxic effects, immunotoxicity, trace elements and C reactive protein (CRP) analyses, were performed in peripheral blood samples collected from individuals of a population living near a deactivated uranium mine. C reactive protein analysis was performed to exclude candidates with active inflammatory processes from further evaluations. DNA damage and immunotoxicity (immunophenotyping and immune cell counts) were evaluated by comet assay and flow cytometry, respectively. Significant DNA damage was observed in the peripheral blood samples from volunteers living in the Cunha Baixa village. A significant decrease of NK and T lymphocytes counts were observed in the individuals from the Cunha Baixa village, when compared with individuals from the reference site. Uranium and manganese levels were significantly higher in the Cunha Baixa village inhabitants. On the other hand, zinc levels were significantly lower in those individuals when compared with the volunteers from the control village. Results suggest that inhabitants from Cunha Baixa have a higher risk of suffering from serious diseases such as cancer, since high DNA damages were observed in peripheral blood leukocytes and also decreased levels of NK and T cells, which play an essential role in the defense against tumor growth

  7. 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

  8. CURIE: Cubesat Radio Interferometry Experiment

    Science.gov (United States)

    Sundkvist, D. J.; Saint-Hilaire, P.; Bain, H. M.; Bale, S. D.; Bonnell, J. W.; Hurford, G. J.; Maruca, B.; Martinez Oliveros, J. C.; Pulupa, M.

    2016-12-01

    The CUbesat Radio Interferometry Experiment (CURIE) is a proposed two-element radio interferometer, based on proven and developed digital radio receivers and designed to fit within a Cubesat platform. CURIE will launch as a 6U Cubesat and then separate into two 3U Cubesats once in orbit. CURIE measures radio waves from 0.1-19MHz, which must be measured from space, as those frequencies fall below the cutoff imposed by Earth's ionosphere. The principal science objective for CURIE is to use radio interferometry to study radio burst emissions from solar eruptive events such as flares and coronal mass ejections (CMEs) in the inner heliosphere, providing observations important for our understanding of the heliospheric space weather environment. The influence of space weather can be felt at Earth and other planets, as radiation levels increase and lead to auroral activity and geomagnetic effects. CURIE will be able to determine the location and size of radio burst source regions and then to track their movement outward from the Sun. In addition to the primary objective CURIE will measure the gradients of the local ionospheric density and electron temperature on the spatial scale of a few kilometers, as well as create an improved map of the radio sky at these unexplored frequencies. A space based radio interferometry observatory has long been envisioned, in orbit around the Earth or the Moon, or on the far side of the Moon. Beyond its important science objectives, CURIE will prove that the concept of a dedicated space-based interferometer can be realized by using relatively cheap Cubesats. CURIE will therefore not only provide new important science results but also serve as a pathfinder in the development of new space-based radio observation techniques for helio- and astro-physics.

  9. 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...

  10. MUSIC RADIO-JOURNALISM

    Directory of Open Access Journals (Sweden)

    Dubovtceva Ludmila I.

    2014-04-01

    Full Text Available The article is based on years of practical experience, the author highlights the main radio genres in which music correspondent, music reviewer, music commentator, and music leading and a disc jockey work. Theoretical principles of their creative activities are analyzed in common journalistic genres, such as interview, reportage, talk show, live broadcast, radiofilm, as well as specialized genres like concert on demand and music competition. Journalist’ speech is seen as a logical element, the incoming with music in art-structural relationships. However, it does not become the predominant sound layer and aims to harmonious correlation or local penetration into music opus. In addition, important links in music journalism are defined the auxiliary "offscreen" editor's job and keeping the original sound archive. The author cites a number of own work examples on the air.

  11. Radio-isotopic tracers

    International Nuclear Information System (INIS)

    Wolfangel, R.G.

    1976-01-01

    The invention concerns the dispersions that may be used for preparing radio-isotopic tracers, technetium labelled dispersions, processes for preparing these dispersions and their use as tracers. Technetium 99m sulphur colloids are utilized as scintillation tracers to give a picture of the reticulo-endothelial system, particularly the liver and spleen. A dispersion is provided which only requires the addition of a radioactive nuclide to form a radioactively labelled dispersion that can be injected as a tracer. It is formed of a colloid of tin sulphur dispersed in an aqueous buffer solution. Such a reagent has the advantage of being safe and reliable and is easier to use. The colloid can be prepared more quickly since additions of several different reagents are avoided. There is no need to heat up and no sulphuretted hydrogen, which is a toxic gas, is used [fr

  12. Radio opaque gloves

    International Nuclear Information System (INIS)

    Whittaker, A.V.; Whittaker, R.E. Jr.; Goldstrom, R.A.; Shipko, F.J.

    1975-01-01

    Radiation shielding garments and accessories, such as radio-opaque gloves for surgeons, shielding against the harmful x-ray radiation in a fluoroscopic zone, are advantageously different from garments for shielding from other medical uses of x-rays. Such garments are provided with zones of differing opacity, whereby desired sensitivity and ''feel'' through the glove material is retained. One feature is the provision of an ''opacity gradient'' across the glove cross section with opacity being relatively low at the fingertip area (lesser shield-thickness), but relatively high at the less nonprehensile hand zones, such as the palm. Glove fabrication techniques for achieving such an opacity gradient are described. (U.S.)

  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. 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.

  15. A Radio Astronomy Science Education Partnership - GAVRT and Radio JOVE

    Science.gov (United States)

    Higgins, C. A.; Thieman, J. R.; Bunnell, K.; Soholt, G.

    2009-12-01

    The planet Jupiter provides an excellent subject to educate, engage, and inspire students and teachers to learn science. The Goldstone Apple-Valley Radio Telescope (GAVRT) program (http://www.lewiscenter.org/gavrt) and The Radio JOVE project (http://radiojove.gsfc.nasa.gov) each have a long history of allowing students and teachers to interact with scientists and real radio telescopes. The upcoming Juno mission to Jupiter (2011 launch) allows both GAVRT and Radio JOVE to combine efforts and engage with the NASA Juno mission, thus increasing the excitement and learning potential for teachers, students, and the general public. Teachers can attend workshops for training to operate a 34-meter radio telescope and/or build their own simple radio telescope, both of which can be used directly in the classroom. We will overview some classroom activities and highlight some teacher-student experiences. In addition, we will update our efforts on greater Web-based control of the radio telescopes, as well as highlight our upcoming workshops to allow better access for teachers in different parts of the Country.

  16. Radio Astronomy Explorer /RAE/. I - Observations of terrestrial radio noise.

    Science.gov (United States)

    Herman, J. R.; Caruso, J. A.; Stone, R. G.

    1973-01-01

    Radio Astronomy Explorer (RAE) I data are analyzed to establish characteristics of HF terrestrial radio noise at an altitude of about 6000 km. Time and frequency variations in amplitude of the observed noise well above cosmic noise background are explained on the basis of temporal and spatial variations in ionospheric critical frequency coupled with those in noise source distributions. It is shown that terrestrial radio noise regularly breaks through the ionosphere and reaches RAE with magnitudes 15 dB and more above cosmic noise background, on frequencies above the F-layer critical frequency.

  17. An Unbiased Survey of 500 Nearby Stars for Debris Disks: A JCMT Legacy Program

    NARCIS (Netherlands)

    Matthews, B.C.; Greaves, J.S.; Holland, W.S.; Wyatt, M.C.; Barlow, M.J.; Bastien, P.; Beichman, C.A.; Biggs, A.; Butner, H.M.; Dent, W.R.F.; Francesco, J. Di; Dominik, C.; Fissel, L.; Friberg, P.; Gibb, A.G.; Halpern, M.; Ivison, R.J.; Jayawardhana, R.; Jenness, T.; Johnstone, D.; Kavelaars, J.J.; Marshall, J.L.; Phillips, N.; Schieven, G.; Snellen, I.A.G.; Walker, H.J.; Ward-Thompson, D.; Weferling, B.; White, G.J.; Yates, J.; Zhu, M.; Craigon, A.

    2007-01-01

    We present the scientific motivation and observing plan for an upcoming detection survey for debris disks using the James Clerk Maxwell Telescope. The SCUBA-2 Unbiased Nearby Stars (SUNS) survey will observe 500 nearby main-sequence and subgiant stars (100 of each of the A, F, G, K, and M spectral

  18. Circumnuclear Dust in Nearby Active and Inactive Galaxies. I. Data

    Science.gov (United States)

    Martini, Paul; Regan, Michael W.; Mulchaey, John S.; Pogge, Richard W.

    2003-06-01

    The detailed morphology of the interstellar medium (ISM) in the central kiloparsec of galaxies is controlled by pressure and gravitation. The combination of these forces shapes both circumnuclear star formation and the growth of the central, supermassive black hole. We present visible and near-infrared Hubble Space Telescope images and color maps of 123 nearby galaxies that show the distribution of the cold ISM, as traced by dust, with excellent spatial resolution. These observations reveal that nuclear dust spirals are found in the majority of active and inactive galaxies and they possess a wide range in coherence, symmetry, and pitch angle. We have used this large sample to develop a classification system for circumnuclear dust structures. In spite of the heterogeneous nature of the complete sample, we only find symmetric, two-arm nuclear dust spirals in galaxies with large-scale bars, and these dust lanes clearly connect to dust lanes along the leading edges of the large-scale bars. Not all dust lanes along large-scale bars form two-arm spirals, however, and several instead end in nuclear rings. We find that tightly wound, or low pitch angle, nuclear dust spirals are more common in unbarred galaxies than barred galaxies. Finally, the extended narrow-line region in several of the active galaxies is well resolved. The connection between the ionized gas and circumnuclear dust lanes in four of these galaxies provides additional evidence that a significant fraction of their extended narrow-line region is ambient gas photoionized in situ by the active nucleus. In a future paper we will use our classification system for circumnuclear dust to identify differences between active and inactive galaxies, as well as barred and unbarred galaxies, in well-matched subsamples of these data. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in

  19. MOLECULAR GAS AND STAR FORMATION IN NEARBY DISK GALAXIES

    International Nuclear Information System (INIS)

    Leroy, Adam K.; Munoz-Mateos, Juan-Carlos; Walter, Fabian; Sandstrom, Karin; Meidt, Sharon; Rix, Hans-Walter; Schinnerer, Eva; Schruba, Andreas; Bigiel, Frank; Bolatto, Alberto; Brinks, Elias; De Blok, W. J. G.; Rosolowsky, Erik; Schuster, Karl-Friedrich; Usero, Antonio

    2013-01-01

    We compare molecular gas traced by 12 CO (2-1) maps from the HERACLES survey, with tracers of the recent star formation rate (SFR) across 30 nearby disk galaxies. We demonstrate a first-order linear correspondence between Σ mol and Σ SFR but also find important second-order systematic variations in the apparent molecular gas depletion time, τ dep mol =Σ mol /Σ SFR . At the 1 kpc common resolution of HERACLES, CO emission correlates closely with many tracers of the recent SFR. Weighting each line of sight equally, using a fixed α CO equivalent to the Milky Way value, our data yield a molecular gas depletion time, τ dep mol =Σ mol /Σ SFR ∼2.2 Gyr with 0.3 dex 1σ scatter, in very good agreement with recent literature data. We apply a forward-modeling approach to constrain the power-law index, N, that relates the SFR surface density and the molecular gas surface density, Σ SFR ∝Σ mol N . We find N = 1 ± 0.15 for our full data set with some scatter from galaxy to galaxy. This also agrees with recent work, but we caution that a power-law treatment oversimplifies the topic given that we observe correlations between τ dep mol and other local and global quantities. The strongest of these are a decreased τ dep mol in low-mass, low-metallicity galaxies and a correlation of the kpc-scale τ dep mol with dust-to-gas ratio, D/G. These correlations can be explained by a CO-to-H 2 conversion factor (α CO ) that depends on dust shielding, and thus D/G, in the theoretically expected way. This is not a unique interpretation, but external evidence of conversion factor variations makes this the most conservative explanation of the strongest observed τ dep mol trends. After applying a D/G-dependent α CO , some weak correlations between τ dep mol and local conditions persist. In particular, we observe lower τ dep mol and enhanced CO excitation associated with nuclear gas concentrations in a subset of our targets. These appear to reflect real enhancements in the

  20. Backyard Worlds: Finding Nearby Brown Dwarfs Through Citizen Science

    Science.gov (United States)

    Kuchner, Marc

    Recent discoveries of cool brown dwarfs in the solar neighborhood and microlensing surveys both point to an undiscovered population of brown dwarfs and rogue planets in the solar neighborhood. We propose to develop and sustain a novel website that enables a unique and powerful citizen-science based search for these and other high-proper-motion objects at 3.5 and 4.6 microns. Through this search, we have an opportunity to discover new ultracool Y dwarfs, crucial links between star formation and planet formation, and also the Sun's nearest neighbors-potentially a system closer than Proxima Centauri. NASA's Wide-field Infrared Survey Explorer mission (WISE) is nominally sensitive enough to detect a 250 K brown dwarf to > 6 pc and even a Jupiter analog to > 0.6 pc. However, high proper motion objects like these can easily be confused with variable stars, electronic noise, latent images, optical ghosts, cosmic ray hits, and so on in the WISE archive. Computer-based searches for high-proper motion objects falter in dense star fields, necessitating visual inspection all candidates. Our citizen science project, called "Backyard Worlds: Planet 9", remedies this problem by engaging volunteers to visually inspect WISE and NEOWISE images. Roughly 104,000 participants have already begun using a preliminary version of the site to examine time-resolved co-adds of unWISE-processed images, four epochs spanning 2010 to 2014. They have already performed more than 3.6 million classifications of these images since the site's launch on February 15, 2017. Besides seeking new brown dwarfs and nearby stars, this site is also the most sensitive all-sky WISE-based search for a planet orbiting the Sun beyond Pluto (sometimes called Planet Nine). Preliminary analysis data from the site has resulted in the discovery of 13 brown dwarf candidates including 6 T dwarfs. We obtained a spectrum of one of these candidates and published it in Astrophysical Journal Letters, with four citizen scientists

  1. Effects of Lateral and Terminal Chains of X-Shaped Bolapolyphiles with Oligo(phenylene ethynylene Cores on Self-Assembly Behavior. Part 2: Domain Formation by Self-Assembly in Lipid Bilayer Membranes

    Directory of Open Access Journals (Sweden)

    Stefan Werner

    2017-09-01

    Full Text Available Supramolecular self-assembly of membrane constituents within a phospholipid bilayer creates complex functional platforms in biological cells that operate in intracellular signaling, trafficking and membrane remodeling. Synthetic polyphilic compounds of macromolecular or small size can be incorporated into artificial phospholipid bilayers. Featuring three or four moieties of different philicities, they reach beyond ordinary amphiphilicity and open up avenues to new functions and interaction concepts. Here, we have incorporated a series of X-shaped bolapolyphiles into DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine bilayers of giant unilamellar vesicles. The bolapolyphiles consist of a rod-like oligo(phenylene ethynylene (OPE core, hydrophilic glycerol-based headgroups with or without oligo(ethylene oxide expansions at both ends and two lateral alkyl chains attached near the center of the OPE core. In the absence of DPPC and water, the compounds showed thermotropic liquid-crystalline behavior with a transition between polyphilic and amphiphilic assembly (see part 1 in this issue. In DPPC membranes, various trends in the domain morphologies were observed upon structure variations, which entailed branched alkyl chains of various sizes, alkyl chain semiperfluorination and size expansion of the headgroups. Observed effects on domain morphology are interpreted in the context of the bulk behavior (part 1 and of a model that was previously developed based on spectroscopic and physicochemical data.

  2. Technology, Empowerment and Community Radio

    OpenAIRE

    Salvatore Scifo

    2015-01-01

    This article will provide an overview of the conceptual contours of community media and community radio, highlighting some of the key questions shaping the debate and, with the help of a case study, show how digital media in the context of community radio can help local groups to get a voice in their local media systems, and how a university-based radio station, and its students and volunteers, play an important role for a more diverse and vibrant media content available in their area.

  3. Introduction to international radio regulations

    International Nuclear Information System (INIS)

    Struzak, R.

    2003-01-01

    These notes introduce the ITU Radio Regulations and related UN and WTO agreements that specify how terrestrial and satellite radio should be used in all countries over the planet. Access to the existing information infrastructure, and to that of the future Information Society, depends critically on these regulations. The paper also discusses few problems related to the use of the radio frequencies and satellite orbits. The notes are extracted from a book under preparation, in which these issues are discussed in more detail. (author)

  4. Magnetogasdynamics of double radio sources

    International Nuclear Information System (INIS)

    Nepveu, M.

    1979-01-01

    The magnetogasdynamical behaviour of plasmoids moving through an ambient gas is investigated numerically with a two-dimensional code, based on the SHASTA scheme. The astrophysical importance of this study lies in the observed extended extragalactic radio sources. It is assumed that plasma clouds with cylinder symmetry are ejected from the nucleus of a galaxy. Their large-scale evolution in the intergalactic medium (IGM) is followed. The gas dynamics of an ejected cloud, the magnetogasdynamics of ejected clouds, the Christiansen-Pacholczyk-Scott picture for radio galaxies and the shear layers in double radio sources are studied. (Auth.)

  5. Shoestring Budget Radio Astronomy (Abstract)

    Science.gov (United States)

    Hoot, J. E.

    2017-12-01

    (Abstract only) 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. A radio and optical study of Molonglo radio sources

    Science.gov (United States)

    Ishwara-Chandra, C. H.; Saikia, D. J.; McCarthy, P. J.; van Breugel, W. J. M.

    2001-05-01

    We present multi-wavelength radio observations with the Very Large Array, and narrow- and broad-band optical observations with the 2.5-m telescope at the Las Campanas Observatory, of a well-defined sample of high-luminosity Fanaroff-Riley class II radio galaxies and quasars, selected from the Molonglo Reference Catalogue 1-Jy sample. These observations were carried out as part of a programme to investigate the effects of orientation and environment on some of the observed properties of these sources. We examine the dependence of the Liu-Pooley relationship, which shows that radio lobes with flatter radio spectra are less depolarized, on size, identification and redshift, and show that it is significantly stronger for smaller sources, with the strength of the relationship being similar for both radio galaxies and quasars. In addition to Doppler effects, there appear to be intrinsic differences between the lobes on opposite sides. We discuss the asymmetry in brightness and location of the hotspots, and present estimates of the ages and velocities from matched-resolution observations in the L and C bands. Narrow- and broad-band optical images of some of these sources were made to study their environments and correlate with the symmetry parameters. An extended emission-line region is seen in a quasar, and in four of the objects possible companion galaxies are seen close to the radio axis.

  7. Radio-adaptive response

    International Nuclear Information System (INIS)

    Ikushima, T.

    1992-01-01

    An adaptive response to radiation stress was found as a suppressed induction of chromosomal damage including micronuclei and sister chromatid exchanges in cultured Chinese hamster V79 cells pre-exposed to very low doses of ionizing radiations. The mechanism underlying this novel chromosomal response, called 'radio-adaptive response (RAR)' has been studied progressively. The following results were obtained in recent experiments. 1. Low doses of β-rays from tritiated water (HTO) as well as tritium-thymidine can cause RAR. 2. Thermal neutrons, a high LET radiation, can not act as tritium β-rays or γ-rays. 3. The RAR expression is suppressed not only by the treatment with an inhibitor of protein synthesis but also by RNA synthesis inhibition. 4. Several proteins are newly synthesized concurrently with the RAR expression after the adapting doses, viewed by two-dimensional electrophoresis of cellular proteins. These results suggests that the RAR might be a cellular stress response to a signal produced preferentially by very low doses of low LET radiation under restricted conditions, accompany the inducible specific gene expression. (author)

  8. Beamsteerable GNSS Radio Occultation ASIC

    Data.gov (United States)

    National Aeronautics and Space Administration — We will develop an integrated RF ASIC to enable high quality radio occultation (RO) weather observations using the Global Navigations System Satellite (GNSS)...

  9. 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...

  10. 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...

  11. Zero-Power Radio Device.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-01

    This report describes an unpowered radio receiver capable of detecting and responding to weak signals transmit ted from comparatively long distances . This radio receiver offers key advantages over a short range zero - power radio receiver previously 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 Laboratories over many years. It uses surface acoustic wave (SAW) filter technology. It uses custom component design to enable the efficient use of small 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].

  12. EVA Radio DRATS 2011 Report

    Science.gov (United States)

    Swank, Aaron J.; Bakula, Casey J.

    2012-01-01

    In the Fall of 2011, National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) participated in the Desert Research and Technology Studies (DRATS) field experiments held near Flagstaff, Arizona. The objective of the DRATS outing is to provide analog mission testing of candidate technologies for space exploration, especially those technologies applicable to human exploration of extra- terrestrial rocky bodies. These activities are performed at locations with similarities to extra-terrestrial conditions. This report describes the Extravehicular Activity (EVA) Dual-Band Radio Communication System which was demonstrated during the 2011 outing. The EVA radio system is designed to transport both voice and telemetry data through a mobile ad hoc wireless network and employs a dual-band radio configuration. Some key characteristics of this system include: 1. Dual-band radio configuration. 2. Intelligent switching between two different capability wireless networks. 3. Self-healing network. 4. Simultaneous data and voice communication.

  13. 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

  14. Radio astronomy on the moon

    International Nuclear Information System (INIS)

    Burns, J.O.; Asbell, J.

    1987-01-01

    The advantages and opportunities for radio astronomy on the moon during the early to mid 21st century are reviewed. In particular, it is argued that the lack of atmosphere, the extremely low seismic activity, the low RF background, and the natural cryogenic environment make the moon (particularly the far side and the poles) a nearly ideal locale for submillimeter/FIR to VLF (below 10 MHz) radio astronomy. 22 references

  15. FRB 121102: A Repeatedly Combed Neutron Star by a Nearby Low-luminosity Accreting Supermassive Black Hole

    Science.gov (United States)

    Zhang, Bing

    2018-02-01

    The origin of fast radio bursts (FRBs) remains mysterious. Recently, the only repeating FRB source, FRB 121102, was reported to possess an extremely large and variable rotation measure (RM). The inferred magnetic field strength in the burst environment is comparable to that in the vicinity of the supermassive black hole Sagittarius A* of our Galaxy. Here, we show that all of the observational properties of FRB 121102 (including the high RM and its evolution, the high linear polarization degree, an invariant polarization angle across each burst and other properties previously known) can be interpreted within the “cosmic comb” model, which invokes a neutron star with typical spin and magnetic field parameters whose magnetosphere is repeatedly and marginally combed by a variable outflow from a nearby low-luminosity accreting supermassive black hole in the host galaxy. We propose three falsifiable predictions (periodic “on/off” states, and periodic/correlated variation of RM and polarization angle) of the model and discuss other FRBs within the context of the cosmic comb model as well as the challenges encountered by other repeating FRB models in light of the new observations.

  16. Thermal radio emission : The brightness temperature and the spectral index of radio emission

    OpenAIRE

    Prigara, F. V.

    2001-01-01

    The condition of radio emission is proposed, on the base of which the theory of themal radio emission for gaseous disk is developed. This theory explains the radio emission spectra of known types of extended radio sources, located beyond the Solar planetary system. Besides, the thermal radio emission spectra of Venus and Jupiter are explained.

  17. Radio galaxies and their environment

    International Nuclear Information System (INIS)

    van Breugel, W.

    1993-01-01

    The relationships between radio galaxies and their environment are varied, complex, and evolve with cosmic epoch. Basic questions are what role the environment plays in triggering and fuelling (radio) galaxy activity what the effects of this activity are on its environment, and how radio galaxies and environment evolve. Clearly, this could be the topic of a workshop all in itself and the scope of this review will necessarily be limited. A review of the connections between environment and galaxy activity in general has been given by Heckman. First, I will briefly summarize the relationships between parent galaxy and cluster environments, and radio galaxies. A more detailed discussion of various aspects of this will be given elsewhere by F. Owen, J.0. Burns and R. Perley. I will then discuss the current status of investigations of extended emission-line regions in radio galaxies, again referring elsewhere in this volume for more detailed discussions of some particular aspects (kinematics and ionization mechanisms by K. Meisenheimer; polarization and spectral index lobe asymmetries by G. Pooley). I will conclude with a brief discussion of the current status of observations of high redshift radio galaxies

  18. 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.

  19. 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.

  20. Bright radio emission from an ultraluminous stellar-mass microquasar in M 31.

    Science.gov (United States)

    Middleton, Matthew J; Miller-Jones, James C A; Markoff, Sera; Fender, Rob; Henze, Martin; Hurley-Walker, Natasha; Scaife, Anna M M; Roberts, Timothy P; Walton, Dominic; Carpenter, John; Macquart, Jean-Pierre; Bower, Geoffrey C; Gurwell, Mark; Pietsch, Wolfgang; Haberl, Frank; Harris, Jonathan; Daniel, Michael; Miah, Junayd; Done, Chris; Morgan, John S; Dickinson, Hugh; Charles, Phil; Burwitz, Vadim; Della Valle, Massimo; Freyberg, Michael; Greiner, Jochen; Hernanz, Margarita; Hartmann, Dieter H; Hatzidimitriou, Despina; Riffeser, Arno; Sala, Gloria; Seitz, Stella; Reig, Pablo; Rau, Arne; Orio, Marina; Titterington, David; Grainge, Keith

    2013-01-10

    A subset of ultraluminous X-ray sources (those with luminosities of less than 10(40) erg s(-1); ref. 1) are thought to be powered by the accretion of gas onto black holes with masses of ∼5-20M cicled dot, probably by means of an accretion disk. The X-ray and radio emission are coupled in such Galactic sources; the radio emission originates in a relativistic jet thought to be launched from the innermost regions near the black hole, with the most powerful emission occurring when the rate of infalling matter approaches a theoretical maximum (the Eddington limit). Only four such maximal sources are known in the Milky Way, and the absorption of soft X-rays in the interstellar medium hinders the determination of the causal sequence of events that leads to the ejection of the jet. Here we report radio and X-ray observations of a bright new X-ray source in the nearby galaxy M 31, whose peak luminosity exceeded 10(39) erg s(-1). The radio luminosity is extremely high and shows variability on a timescale of tens of minutes, arguing that the source is highly compact and powered by accretion close to the Eddington limit onto a black hole of stellar mass. Continued radio and X-ray monitoring of such sources should reveal the causal relationship between the accretion flow and the powerful jet emission.

  1. Nearby supernova factory announces 34 supernovae in one year'; best Rookie year ever for supernova search

    CERN Multimedia

    2003-01-01

    The Nearby Supernova Factory (SNfactory), an international collaboration based at Lawrence Berkeley National Laboratory, announced that it had discovered 34 supernovae during the first year of the prototype system's operation (2 pages).

  2. Robo-AO Kepler Survey. IV. The Effect of Nearby Stars on 3857 Planetary Candidate Systems

    Science.gov (United States)

    Ziegler, Carl; Law, Nicholas M.; Baranec, Christoph; Riddle, Reed; Duev, Dmitry A.; Howard, Ward; Jensen-Clem, Rebecca; Kulkarni, S. R.; Morton, Tim; Salama, Maïssa

    2018-04-01

    We present the overall statistical results from the Robo-AO Kepler planetary candidate survey, comprising of 3857 high-angular resolution observations of planetary candidate systems with Robo-AO, an automated laser adaptive optics system. These observations reveal previously unknown nearby stars blended with the planetary candidate host stars that alter the derived planetary radii or may be the source of an astrophysical false positive transit signal. In the first three papers in the survey, we detected 440 nearby stars around 3313 planetary candidate host stars. In this paper, we present observations of 532 planetary candidate host stars, detecting 94 companions around 88 stars; 84 of these companions have not previously been observed in high resolution. We also report 50 more-widely separated companions near 715 targets previously observed by Robo-AO. We derive corrected planetary radius estimates for the 814 planetary candidates in systems with a detected nearby star. If planetary candidates are equally likely to orbit the primary or secondary star, the radius estimates for planetary candidates in systems with likely bound nearby stars increase by a factor of 1.54, on average. We find that 35 previously believed rocky planet candidates are likely not rocky due to the presence of nearby stars. From the combined data sets from the complete Robo-AO KOI survey, we find that 14.5 ± 0.5% of planetary candidate hosts have a nearby star with 4″, while 1.2% have two nearby stars, and 0.08% have three. We find that 16% of Earth-sized, 13% of Neptune-sized, 14% of Saturn-sized, and 19% of Jupiter-sized planet candidates have detected nearby stars.

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

    International Nuclear Information System (INIS)

    Zhang, Bing

    2017-01-01

    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.

  4. 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.

  5. Fast radio bursts: the observational case for a Galactic origin

    Science.gov (United States)

    Maoz, Dan; Loeb, Abraham; Shvartzvald, Yossi; Sitek, Monika; Engel, Michael; Kiefer, Flavien; Kiraga, Marcin; Levi, Amir; Mazeh, Tsevi; Pawlak, Michał; Rich, R. Michael; Tal-Or, Lev; Wyrzykowski, Lukasz

    2015-12-01

    There are by now ten published detections of fast radio bursts (FRBs) - single bright GHz-band millisecond pulses of unknown origin. Proposed explanations cover a broad range from exotic processes at cosmological distances to atmospheric and terrestrial sources. Loeb, Maoz, and Shvartzvald have previously suggested that FRB sources could be nearby flare stars, and pointed out the presence of a W-UMa-type contact binary within the beam of one out of three FRB fields that they examined. To further test the flare-star hypothesis, we use time-domain optical photometry and spectroscopy, and now find possible flare stars in additional FRB fields, with one to three such cases among all eight FRB fields studied. We evaluate the chance probabilities of these possible associations to be in the range ˜0.1 per cent to 9 per cent, depending on the input assumptions. Further, we re-analyse the probability that two FRBs recently discovered three years apart within the same radio beam are unrelated. Contrary to other claims, we conclude with 99 per cent confidence that the two events are from the same repeating source. The different dispersion measures between the two bursts then rule out a cosmological intergalactic-medium origin for the dispersion measure, but are consistent with the flare-star scenario with a varying plasma blanket between bursts. Finally, we review some theoretical objections that have been raised against a local flare-star FRB origin, and show that they are incorrect.

  6. 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.

  7. Radio science investigations with Voyager

    International Nuclear Information System (INIS)

    Eshleman, V.R.; Tyler, G.L.; Croft, T.A.

    1977-01-01

    The planned radio science investigations during the Voyager missions to the outer planets involve: (1) the use of the radio links to and from the spacecraft for occultation measurements of planetary and satellite atmospheres and ionospheres, the rings of Saturn, the solar corona, and the general-relativistic time delay for radiowave propagation through the Sun's gravity field; (2) radio link measurements of true or apparent spacecraft motion caused by the gravity fields of the planets, the masses of their larger satellites, and characteristics of the interplanetary medium; and (3) related measurements which could provide results in other areas, including the possible detection of long-wavelength gravitational radiation propagating through the Solar System. The measurements will be used to study: atmospheric and ionospheric structure, constituents, and dynamics; the sizes, radial distribution, total mass, and other characteristics of the particles in the rings of Saturn; interior models for the major planets and the mean density and bulk composition of a number of their satellites; the plasma density and dynamics of the solar corona and interplanetary medium; and certain fundamental questions involving gravitation and relativity. The instrumentation for these experiments is the same ground-based and spacecraft radio systems as will be used for tracking and communicating with the Voyager spacecraft, although several important features of these systems have been provided primarily for the radio science investigations. (Auth.)

  8. A Radio Continuum Study of Dwarf Galaxies: 6 cm Imaging of LITTLE THINGS

    Science.gov (United States)

    Hindson, Luke; Kitchener, Ged; Brinks, Elias; Heesen, Volker; Westcott, Jonathan; Hunter, Deidre; Zhang, Hong-Xin; Rupen, Michael; Rau, Urvashi

    2018-02-01

    In this paper, we examine to what extent the radio continuum can be used as an extinction-free probe of star formation in dwarf galaxies. To that aim, we observe 40 nearby dwarf galaxies with the Very Large Array at 6 cm (4–8 GHz) in C-configuration. We obtained images with 3″–8″ resolution and noise levels of 3–15 μJy beam‑1. We detected emission associated with 22 of the 40 dwarf galaxies, eight of which are new detections. The general picture is that of an interstellar medium largely devoid of radio continuum emission, interspersed by isolated pockets of emission associated with star formation. We find an average thermal fraction of ∼50%–70% and an average magnetic field strength of ∼5–8 μG, only slightly lower than that found in larger, spiral galaxies. At 100 pc scales, we find surprisingly high values for the average magnetic field strength of up to 50 μG. We find that dwarf galaxies follow the theoretical predictions of the radio continuum–star formation rate relation within regions of significant radio continuum emission but that the nonthermal radio continuum is suppressed relative to the star formation rate when considering the entire optical disk. We examine the far-infrared–star formation rate relation for our sample and find that the far-infrared is suppressed compared to the expected star formation rate. We discuss explanations for these observed relations and the impact of our findings on the radio continuum–far-infrared relation. We conclude that radio continuum emission at centimeter wavelengths has the promise of being a largely extinction-free star formation rate indicator. We find that star formation rates of gas-rich, low-mass galaxies can be estimated with an uncertainty of ±0.2 dex between the values of 2 × 10‑4 and 0.1 M ⊙ yr‑1.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. RESOLUTION OF THE COMPACT RADIO CONTINUUM SOURCES IN Arp220

    International Nuclear Information System (INIS)

    Batejat, Fabien; Conway, John E.; Hurley, Rossa; Parra, Rodrigo; Diamond, Philip J.; Lonsdale, Colin J.; Lonsdale, Carol J.

    2011-01-01

    We present 2 cm and 3.6 cm wavelength very long baseline interferometry images of the compact radio continuum sources in the nearby ultra-luminous infrared galaxy Arp220. Based on their radio spectra and variability properties, we confirm these sources to be a mixture of supernovae (SNe) and supernova remnants (SNRs). Of the 17 detected sources we resolve 7 at both wavelengths. The SNe generally only have upper size limits. In contrast all the SNRs are resolved with diameters ≥0.27 pc. This size limit is consistent with them having just entered their Sedov phase while embedded in an interstellar medium (ISM) of density 10 4 cm -3 . These objects lie on the diameter-luminosity correlation for SNRs (and so also on the diameter-surface brightness relation) and extend these correlations to very small sources. The data are consistent with the relation L∝D -9/4 . Revised equipartition arguments adjusted to a magnetic field to a relativistic particle energy density ratio of 1% combined with a reasonable synchrotron-emitting volume filling factor of 10% give estimated magnetic field strengths in the SNR shells of ∼15-50 mG. The SNR shell magnetic fields are unlikely to come from compression of ambient ISM fields and must instead be internally generated. We set an upper limit of 7 mG for the ISM magnetic field. The estimated energy in relativistic particles, 2%-20% of the explosion kinetic energy, is consistent with estimates from models that fit the IR-radio correlation in compact starburst galaxies.

  16. 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.

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

    African Journals Online (AJOL)

    eobe

    which is 9mW/m2 for the public and 22.5mW/m2 for those professionals invo for those professionals involved in telecommunication industry. lved in telecommunication industry. lved in telecommunication industry. Keywords: Radio Frequency Electromagnetic Radiation, Base Station Antenna, Power density, international.

  18. 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.

  19. The Dynamics of Radio Galaxies and Double–Double Radio ...

    Indian Academy of Sciences (India)

    continuum: galaxies—galaxies: individual: 3C457, J0041+3224. 1. Introduction. Radio galaxies are created by Active Galactic Nuclei (AGNs) which eject jets in two opposite directions and inflate what are called lobes. This jet-forming activity of an. AGN may be episodic in nature. A striking example of episodic jet forming ...

  20. 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 ...

  1. The inner radio structure of Centaurus A - Clues to the origin of the jet X-ray emission

    Science.gov (United States)

    Burns, J. O.; Feigelson, E. D.; Schreier, E. J.

    1983-01-01

    VLA observations at 1.4 and 4.9 GHz of the jet and inner lobes of the nearby radio galaxy Centaurus A have been used to construct maps of total intensity and polarization at resolutions of 31 x 10 and 3.6 x 1.1 arcsec. Surface brightness and pressure distributions in the jet, combined with the apparent X-ray emission from the ISM of NGC 5128, indicate that it is thermally confined. A comparison of the radio structure and the optical galaxy shows that the jet in Cen A emerges nearly along the major axis of the elliptical stellar component that is parallel to the angular momentum vector of the dust lane. The outer radio structure bends toward the galaxy minor axis. Evidence is found for a common synchrotron radiation origin of the full spectrum jet emission.

  2. Meteor observations of forward-scattered FM-radio echo in Busan (Korea)

    Science.gov (United States)

    Kim, K.-M.; Cho, M.; Kim, T.; Hong, J.; Kang, Y.-W.; Ahn, S.-H.; Lee, S. H.; Song, I.-O.

    2015-01-01

    The detection system of forward-scattered FM-radio signals has been newly set up in Korea Science Academy of KAIST in Busan, Korea. The meteor observations using a 2.5m-long Yagi antenna have been carried out since May, 2015. The radio station we use is the NHK broadcasting station (85.20MHz) located in Hokkaido, Japan which is approximately 1,400 km away from Busan and is well below the local horizon. The detection is successfully running, and we examine the observed data reliability by simply checking long-lasting echoes. An additional observing station is being installed in the nearby city of Ulsan to make a cross-check. We analyze the results to find the diurnal and daily variation of the meteor rates. We are planning to pursue long-term observations in order to educate students.

  3. Compressed Sensing for Wideband Cognitive Radios

    National Research Council Canada - National Science Library

    Tian, Zhi; Giannakis, Georgios B

    2007-01-01

    In the emerging paradigm of open spectrum access, cognitive radios dynamically sense the radio-spectrum environment and must rapidly tune their transmitter parameters to efficiently utilize the available spectrum...

  4. 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

  5. A Digital Radio Receiver for Ionospheric Research

    National Research Council Canada - National Science Library

    James, H. G

    2006-01-01

    .... One of the radio instruments is a four-channel digital Radio Receiver Instrument (RRI). RRI will be fed by four 3-metre monopoles, arranged in a crossed configuration, each connected to a high-input impedance...

  6. 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.

  7. 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

  8. Hybrid spread spectrum radio system

    Science.gov (United States)

    Smith, Stephen F [London, TN; Dress, William B [Camas, WA

    2010-02-09

    Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

  9. Radio Relics in Cosmological Simulations

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... 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, ...

  10. RADIO NOISE ADVANCES SEXUAL MATURITY

    African Journals Online (AJOL)

    ansistf-lewis

    similar to controls maintained on 12-h photoperiods (Lewis & Perry, 1990). In this latter trial it was suggested that the radio noise had anchored the photoinducible phase (PIP, a 4-h period that induces a photosexual response when illuminated) to the position it had occupied in the original 12-h photoperiod, thus enabling it ...

  11. Bolidozor radio meteor detection network

    OpenAIRE

    Jakub Kákona; Martin Kákona

    2015-01-01

    Radio meteor detection networks could improve knowledge about meteors under daylight or inconvenient weather conditions. We present novel approach to the meteor detection system. Hardware described in this poster has unique features for time synchronization of multiple nodes, therefore meteor trajectory calculation is possible in case of appropriate network deployment.

  12. 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.

  13. 47 CFR 90.185 - Multiple licensing of radio transmitting equipment in the mobile radio service.

    Science.gov (United States)

    2010-10-01

    ... 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... mobile radio service. Two or more persons eligible for licensing under this rule part may be licensed for...

  14. 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

  15. 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…

  16. 47 CFR 32.2231 - Radio systems.

    Science.gov (United States)

    2010-10-01

    ..., amplification, propagation, reception, modulation, and demodulation of radio waves in free space over which... 47 Telecommunication 2 2010-10-01 2010-10-01 false Radio systems. 32.2231 Section 32.2231... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2231 Radio systems. (a...

  17. Division B Commission 40: Radio Astronomy

    NARCIS (Netherlands)

    Chapman, Jessica M.; Giovaninni, Gabriele; Taylor, Russell; Carilli, Christopher; Hills, Richard; Hirabayashi, Hisashi; Jonas, Justin L.; Lazio, Joseph; Morganti, Raffaella; Nan, Rendong; Rubio, Monica; Shastri, Prjaval; Kellermann, Ken; Ekers, Ronald; Ohishi, Masatoshi

    2016-01-01

    IAU Commission 40 for Radio Astronomy (hereafter C40) brought together scientists and engineers who carry out observational and theoretical research in radio astronomy and who develop and operate the ground and space-based radio astronomy facilities and instrumentation. As of June 2015, the

  18. Radio-Optical Imaging of ATLBS Survey

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... The primary aim of the ATLBS survey is to image low-power radio sources which form the bulk of the radio source population to moderately high red-shifts ( ∼ 1.0). The accompanying multiband optical and near infra-red observations provide information about the hosts and environments of the radio ...

  19. Exploring Community Radio Programming Practices to Inform ...

    African Journals Online (AJOL)

    A collective case study (multi-site) design was used to probe educational programming practices used in community radio. The paper explores how community radio station programming engages listeners in community generated education programmes that are produced through collaborative work with radio listener clubs.

  20. 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...

  1. 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 ...

  2. Radio responding media. Prosumers, media innovation in web-based radio

    OpenAIRE

    Brundu, Gabriella

    2015-01-01

    After a century of traditional broadcasting, this is the history of how the radio as a medium entered the web world, becoming web-based radios. Our case is based on an Italian web-radio, Radio Casa Bertallot, which started to make radio programmes using the possibilities of new media technology and the internet to create a platform for interacting with the users. The founder Alessio Bertallot, expressed his view on the radio production by describing the radio as, a place, as a home, a room, ...

  3. The search for radio emission from exoplanets using LOFAR low-frequency beam-formed observations

    Science.gov (United States)

    Turner, Jake D.; Griessmeier, Jean-Mathias; Zarka, Philippe

    2018-01-01

    Detection of radio emission from exoplanets can provide information on the star-planet system that is very difficult or impossible to study otherwise, such as the planet’s magnetic field, magnetosphere, rotation period, orbit inclination, and star-planet interactions. Such a detection in the radio domain would open up a whole new field in the study of exoplanets, however, currently there are no confirmed detections of an exoplanet at radio frequencies. In this study, we discuss our ongoing observational campaign searching for exoplanetary radio emissions using beam-formed observations within the Low Band of the Low-Frequency Array (LOFAR). To date we have observed three exoplanets: 55 Cnc, Upsilon Andromedae, and Tau Boötis. These planets were selected according to theoretical predictions, which indicated them as among the best candidates for an observation. During the observations we usually recorded three beams simultaneously, one on the exoplanet and two on patches of nearby “empty” sky. An automatic pipeline was created to automatically find RFI, calibrate the data due to instrumental effects, and to search for emission in the exoplanet beam. Additionally, we observed Jupiter with LOFAR with the same exact observational setup as the exoplanet observations. The main goals of the Jupiter observations are to train the detection algorithm and to calculate upper limits in the case of a non-detection. Data analysis is currently ongoing. Conclusions reached at the time of the meeting, about detection of or upper limit to the planetary signal, will be presented.

  4. VizieR Online Data Catalog: Radio observations of SN 2009bb (Soderberg+, 2010)

    Science.gov (United States)

    Soderberg, A. M.; Chakraborti, S.; Pignata, G.; Chevalier, R. A.; Chandra, P.; Ray, A.; Wieringa, M. H.; Copete, A.; Chaplin, V.; Connaughton, V.; Barthelmy, S. D.; Bietenholz, M. F.; Chugai, N.; Stritzinger, M. D.; Hamuy, M.; Fransson, C.; Fox, O.; Levesque, E. M.; Grindlay, J. E.; Challis, P.; Foley, R. J.; Kirshner, R. P.; Milne, P. A.; Torres, M. A. P.

    2010-02-01

    Long duration gamma-ray bursts (GRBs) mark the explosive death of some massive stars and are a rare sub-class of type Ibc supernovae. They are distinguished by the production of an energetic and collimated relativistic outflow powered by a central engine (an accreting black hole or neutron star). Observationally, this outflow is manifested in the pulse of gamma-rays and a long-lived radio afterglow. Until now, central-engine-driven supernovae have been discovered exclusively through their gamma-ray emission, yet it is expected that a larger population goes undetected because of limited satellite sensitivity or beaming of the collimated emission away from our line of sight. In this framework, the recovery of undetected GRBs may be possible through radio searches for type Ibc supernovae with relativistic outflows. Here we report the discovery of luminous radio emission from the seemingly ordinary type Ibc SN 2009bb, which requires a substantial relativistic outflow powered by a central engine. A comparison with our radio survey of type Ibc supernovae reveals that the fraction harbouring central engines is low, about one per cent, measured independently from, but consistent with, the inferred rate of nearby GRBs. Independently, a second mildly relativistic supernova has been reported. (1 data file).

  5. VLF radio wave anomalies associated with the 2010 Ms 7.1 Yushu earthquake

    Science.gov (United States)

    Shen, Xuhui; Zhima, Zeren; Zhao, Shufan; Qian, Geng; Ye, Qing; Ruzhin, Yuri

    2017-05-01

    The VLF radio signals recorded both from the ground based VLF radio wave monitoring network and the DEMETER satellite are investigated during the 2010 Ms 7.1 Yushu earthquake. The ground-based observations show that the disturbance intensity of VLF wave's amplitude relative to the background gets an enhancement over 22% at 11.9 kHz, 27% at 12.6 kHz and 62% at 14.9 kHz VLF radio wave along the path from Novosibirsk - TH one day before the main shock, as compared to the maximum 20% observed during non-earthquake time. The space based observations indicate that there is a decrease of the signal to noise ratio (SNR) for the power spectral density data of 14.9 kHz VLF radio signal at electric field four days before the main shock, with disturbance intensity exceeding the background by over 5% as compared to the maximum 3% observed during non-earthquake time. The geoelectric field observations in the epicenter region also show that a sharp enhancement from ∼340 to 430 mV/km simultaneously appeared at two monitors 14 days before main shock. The comparative analysis from the ground and space based observations during the earthquake and non-earthquake time provides us convincible evidence that there exits seismic anomalies from the VLF radio wave propagation before the 2010 Ms 7.1 Yushu earthquake. The possible mechanism for VLF radio signal propagation anomaly during 2010 Yushu earthquake maybe related to the change of the geoelectric field nearby the earthquake zone.

  6. Radio Astronomy Explorer (RAE) 1 observations of terrestrial radio noise

    Science.gov (United States)

    Herman, J. R.; Caruso, J. A.

    1971-01-01

    Radio Astonomy Explorer (RAE) 1 data are analyzed to establish characteristics of HF terrestrial radio noise at an altitude of about 6000 km. Time and frequency variations in amplitude of the observed noise well above cosmic noise background are explained on the basis of temporal and spatial variations in ionospheric critical frequency coupled with those in noise source distributions. It is shown that terrestrial noise regularly breaks through the ionosphere and reaches RAE with magnitudes 15 or more db higher than cosmic noise background. Maximum terrestrial noise is observed when RAE is over the dark side of the Earth in the neighborhood of equatorial continental land masses where thunderstorms occur most frequently. The observed noise level is 30-40 db lower with RAE over oceans.

  7. Effects of nearby buildings on lightning induced voltages on overhead power distribution lines

    OpenAIRE

    Borghetti, Alberto; Napolitano, Fabio; Nucci, Carlo Alberto; Paolone, Mario

    2013-01-01

    For the case of urban overhead lines, the presence of nearby buildings is expected to affect the overvoltages induced by nearby cloud-to-ground lightning return strokes. So far, this effect has been seldom taken into account in the literature on the subject. The paper presents a 3D FEM model that calculates the lightning electromagnetic pulse (LEMP) taking into account the presence of a building placed in proximity of the LEMP-coupled overhead line. As a first approximation, all the metallic ...

  8. 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...

  9. 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.

  10. 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.

  11. 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...

  12. MAPK activation by radio waves.

    Science.gov (United States)

    Arthur, J Simon C

    2007-08-01

    In this issue of the Biochemical Journal, Freidman et al. report the findings of a study to look at the potential of mobile phones to activate intracellular signalling cascades. They found that radio waves corresponding to the frequency commonly used by mobile phones are able to activate ERK1/2 (extracellular-signal-regulated kinases 1 and 2). This effect was observed even at intensities lower than those emitted by mobile phones that are unable to cause any measurable heating effects. This study provides evidence that radio waves induce ERK1/2 activation downstream of the EGF (epidermal growth factor) receptor, which is in turn activated by the release of reactive oxygen species.

  13. 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.

  14. The radio-frequency quadrupole

    CERN Document Server

    Vretenar, Maurizio

    2013-01-01

    Radio-frequency quadrupole (RFQ) linear accelerators appeared on the accelerator scene in the late 1970s and have since revolutionized the domain of low-energy proton and ion acceleration. The RFQ makes the reliable production of unprecedented ion beam intensities possible within a compact radio-frequency (RF) resonator which concentrates the three main functions of the low-energy linac section: focusing, bunching and accelerating. Its sophisticated electrode structure and strict beam dynamics and RF requirements, however, impose severe constraints on the mechanical and RF layout, making the construction of RFQs particularly challenging. This lecture will introduce the main beam optics, RF and mechanical features of a RFQ emphasizing how these three aspects are interrelated and how they contribute to the final performance of the RFQ.

  15. LEP Radio Frequency Copper Cavity

    CERN Multimedia

    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.

  16. A VLA Search for Radio Signals from M31 and M33

    Science.gov (United States)

    Gray, Robert H.; Mooley, Kunal

    2017-03-01

    Observing nearby galaxies would facilitate the search for artificial radio signals by sampling several billions of stars simultaneously, but few efforts have been made to exploit this opportunity. An added attraction is that the Milky Way is the second largest member of the Local Group, so our galaxy might be a probable target for hypothetical broadcasters in nearby galaxies. We present the first relatively high spectral resolution (intelligent radio signals of complete galaxies in the Local Group with the Jansky VLA, observing the galaxies M31 (Andromeda) and M33 (Triangulum)—the first and third largest members of the group, respectively—sampling more stars than any prior search of this kind. We used 122 Hz channels over a 1 MHz spectral window in the target galaxy velocity frame of reference, and 15 Hz channels over a 125 kHz window in our local standard of rest. No narrowband signals were detected above a signal-to-noise ratio of 7, suggesting the absence of continuous narrowband flux greater than approximately 0.24 and 1.33 Jy in the respective spectral windows illuminating our part of the Milky Way during our observations in 2014 December and 2015 January. This is also the first study in which the upgraded VLA has been used for SETI.

  17. Radio occultation exploration of Mars

    International Nuclear Information System (INIS)

    Kliore, A.J.

    1974-01-01

    The radio occultation technique, consisting of the observation of changes in the phase, frequency, and amplitude of a radio signal from a spacecraft as it passes through the atmosphere of a planet before and after occultation, was first applied to measure the atmosphere of Mars with the Mariner IV spacecraft in 1965. The interpretation of these changes in terms of refraction of the radio beam by the neutral atmosphere and ionosphere of the planet provided the first direct and quantitative measurement of its vertical structure and established the surface atmospheric pressure of Mars as lying between 5 and 9 mb. The presence of a daytime ionosphere with a peak electron density of about 10 5 el cm -3 was also measured. The Mariner VI and VII spacecraft flew by Mars in 1969 and provided an additional four measurements of the atmosphere and surface radius of the planet. They confirmed the surface pressure values measured by Mariner IV and provided data for a crude estimate of the shape of the planet. (Auth.)

  18. 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...

  19. Expanding radio astronomy in Africa

    International Nuclear Information System (INIS)

    Gaylard, M J

    2013-01-01

    The Square Kilometre Array (SKA) Organisation announced in May 2012 that its members had agreed on a dual site solution for the SKA [1]. South Africa's bid for hosting the SKA has caused a ramp up of radio astronomy in Africa. To develop technology towards the SKA, the South African SKA Project (SKA SA) built a protoype radio telescope in 2007, followed in 2010 the seven antenna Karoo Array Telescope (KAT-7). Next is the 64 antenna MeerKAT, which will merge into SKA Phase 1 in Africa. As SKA Phase 2 is intended to add a high resolution capability with baselines out to 3000 km, the SKA SA brought in partner countries in Africa to host outstations. South Africa has been working with the partners to build capacity to operate the SKA and to benefit from it. The SA Department of Science and Technology (DST) developed a proposal to establish radio telescopes in the partner countries to provide hands-on learning and a capability for Very Long Baseline Interferometry (VLBI) research. Redundant 30 m class satellite antennas are being incorporated in this project.

  20. Imaging Search for Dynamically Inferred Planets in Nearby Debris Disk Systems [Dataset

    NARCIS (Netherlands)

    Janson, M.; Carson, J.; Lafreniere, D.; Spiegel, D.; Quanz, S.; Thalmann, C.; Amara, A.

    2012-01-01

    The nearby stars Eps Eri, Vega, and Fomalhaut all host large debris disks with morphological structures that can be interpreted as being due to dynamical influence from unseen giant planets residing in the systems. At the ages of the systems of a few hundred Myrs, such planets are expected to have

  1. Impact of Granite Quarrying on the Health of Workers and Nearby ...

    African Journals Online (AJOL)

    Impact of Granite Quarrying on the Health of Workers and Nearby Residents in Abeokuta Ogun State, Nigeria. ... Suspended Particulate Matter (SPM) meter was employed to monitor the level of particulate matter (PM10) within and around five quarry sites selected for this study. The data collected from hospital records of ...

  2. The Star Formation & Chemical Evolution Timescales of Two Nearby Dwarf Spheroidal Galaxies

    NARCIS (Netherlands)

    de Boer, Thomas; Tolstoy, E.; Hill, V.; Saha, A.; Olsen, K.; Starkenburg, E.; Irwin, M.; Battaglia, G.

    We present wide-field photometry of resolved stars in the nearby Sculptor and Fornax dwarf spheroidal galaxies, going down to the oldest Main Sequence Turn-Off. The accurately flux calibrated wide-field Colour-Magnitude Diagrams are used directly in combination with spectroscopic metallicities of

  3. Nuclei of nearby disk galaxies .1. A Hubble Space Telescope imaging survey

    NARCIS (Netherlands)

    Phillips, AC; Illingworth, GD; MacKenty, JW; Franx, M

    We present deconvolved images of the central regions of 20 nearby disk galaxies, obtained with the original Planetary Camera of the Hubble Space Telescope. The galaxies span a range in Hubble type from SO to Sm. We have measured surface brightness profiles, and inverted these to estimate

  4. VLT/UVES abundances in four nearby dwarf spheroidal galaxies. II. Implications for understanding galaxy evolution

    NARCIS (Netherlands)

    Tolstoy, E; Venn, KA; Shetrone, M; Primas, F; Hill, [No Value; Kaufer, A; Szeifert, T

    We have used the Ultraviolet Visual-Echelle Spectrograph (UVES) on Kueyen (UT2) of the Very Large Telescope to take spectra of 15 individual red giant stars in the centers of four nearby dwarf spheroidal galaxies (dSph's) : Sculptor, Fornax, Carina, and Leo I. We measure the abundance variations of

  5. UCAC4 Nearby Star Survey: A Search for Our Stellar Neighbors

    Science.gov (United States)

    Subasavage, John P.; Finch, Charlie T.; Zacharias, Norbert; Henry, Todd J.; Riedel, Adric R.

    2015-01-01

    We present 16 photometric color-M_K relations using the U. S. Naval Observatory Fourth CCD Astrograph Catalog (UCAC4). These relations estimate distances to nearby red dwarfs at the ˜15% accuracy level using photometry from the Two-Micron All-Sky Survey (2MASS) and the AAVSO Photometric All-Sky Survey (APASS). A sample of nearby stars from the Research Consortium On Nearby Stars (RECONS) group along with a supplemental list of very red stars all having accurate trigonometric parallaxes are used to generate the relations. Color, proper motion, and existing literature sources are used in an attempt to attain a clean sample of red dwarfs while limiting the amount of contamination from background giants. From this sample, we find 1761 candidate nearby M dwarfs estimated to be within 25 pc. Of this sample, 339 have no previously known published parallax or distance estimate and five of these are estimated to be within 10 pc. The nearest distance estimate of 5.9 pc was found for a star with V magnitude of 10.5. That several hundred new stars have been revealed so close to the Sun illustrates once again that there is considerable work yet to be done to map the solar neighborhood.

  6. Optical observations of Dwingeloo 1, a nearby barred spiral galaxy behind the Milky Way

    NARCIS (Netherlands)

    Loan, AJ; Maddox, SJ; Lahav, O; Balcells, M; KraanKorteweg, RC; Assendorp, R; Almoznino, E; Brosch, N; Goldberg, E; Ofek, EO

    1996-01-01

    We present new optical observations of the nearby barred spiral galaxy Dwingeloo 1 (Dw1) obtained with the Isaac Newton, William Herschel and Wise telescopes. Dw1 lies at Galactic coordinates (l=138.degrees 52, b=-0.degrees 11) and it is heavily obscured by dust and gas in the Milky Way. We infer

  7. Why Seychelles Warblers fail to recolonize nearby islands : unwilling or unable to fly there?

    NARCIS (Netherlands)

    Komdeur, J; Piersma, T; Kraaijeveld, K; Kraaijeveld-Smit, F; Richardson, DS; Richardson, David S.

    The Seychelles Warbler Acrocephalus sechellensis is a rare island endemic which, from 1920 to 1988, occurred only on Cousin Island (29 ha) in the Seychelles. Despite the saturated nature of this population and the possibility of obtaining higher reproductive success on new nearby islands,

  8. Nearby supernova host galaxies from the CALIFA survey. II. Supernova environmental metallicity

    NARCIS (Netherlands)

    Galbany, L.; Stanishev, V.; Mourão, A. M.; Rodrigues, M.; Flores, H.; Walcher, C. J.; Sánchez, S. F.; García-Benito, R.; Mast, D.; Badenes, C.; González Delgado, R. M.; Kehrig, C.; Lyubenova, M.; Marino, R. A.; Mollá, M.; Meidt, S.; Pérez, E.; van de Ven, G.; Vílchez, J. M.

    2016-01-01

    The metallicity of a supernova progenitor, together with its mass, is one of the main parameters that can rule the progenitor's fate. We present the second study of nearby supernova (SN) host galaxies (0.005 ⊙) > 10 dex) by targeted searches. We neither found evidence that the metallicity at the SN

  9. Resolved 200mu M images of nearby galaxies - evidence for an extended distribution of cold dust

    NARCIS (Netherlands)

    Valentijn, E; Alton, P.B.; Threwhella, M.; Davies, J.I.; Bianchi, S.; Gear, W.; Thronson, H.; Witt, A.

    1998-01-01

    We present resolved 200mu m images for 8 nearby galaxies observed with the Infrared Space Observatory (ISO). By comparing the 200mu m observations with IRAS 60mu m and 100mu m data, we find that cold dust becomes more dominant at larger radii. We infer a grain temperature of 18-21 K for this cold

  10. XMM-Newton view of X-ray overdensities from nearby galaxy clusters : the environmental dependencies

    NARCIS (Netherlands)

    Caglar,; T.; Hudaverdi,; M.,

    2017-01-01

    In this work, we studied ten nearby (z≤0.038) galaxy clusters to understand possible interactions between hot plasma and member galaxies. A multi-band source detection was applied to detect point-like structures within the intra-cluster medium. We examined spectral properties of a total of 391 X-ray

  11. Properly Interpreting the Epidemiologic Evidence about the Health Effects of Industrial Wind Turbines on Nearby Residents

    Science.gov (United States)

    Phillips, Carl V.

    2011-01-01

    There is overwhelming evidence that wind turbines cause serious health problems in nearby residents, usually stress-disorder-type diseases, at a nontrivial rate. The bulk of the evidence takes the form of thousands of adverse event reports. There is also a small amount of systematically gathered data. The adverse event reports provide compelling…

  12. Direct imaging of haloes and truncations in face-on nearby galaxies

    NARCIS (Netherlands)

    Knapen, J. H.; Peters, S. P. C.; van der Kruit, P. C.; Trujillo, I.; Fliri, J.; Cisternas, M.; Kelvin, L. S.; Bragaglia, A.; Arnaboldi, M.; Rejkuba, M.; Romano, D.

    2016-01-01

    We use ultra-deep imaging from the IAC Stripe 82 Legacy Project to study the surface photometry of 22 nearby, face-on to moderately inclined spiral galaxies. The reprocessed and co-added SDSS/Stripe 82 imaging allows us to probe down to 29-30 r'-mag/arcsec2 and thus reach into the very faint

  13. 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.

  14. Fast Radio Bursts and Radio Transients from Black Hole Batteries

    Science.gov (United States)

    Mingarelli, Chiara M. F.; Levin, Janna; Lazio, T. Joseph W.

    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.

  15. 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

  16. Radio Days. the effort to recovery: the radio as integration

    OpenAIRE

    González, Itzíar Martínez; López, Óscar Pérez; Roca, Francisco Javier Bueno; Martín, Manuel Jiménez; Campo, Antonia Ruiz del; Rodríguez, Guillermo Segura; Encabo, Juan Francisco Sigüenza

    2011-01-01

    Desde el Centro de Rehabilitación Psicosocial ("CRPS") Los Cármenes (inscrito dentro de la Red Pública de Atención Social para Personas con Enfermedad Mental Grave y Duradera, dependiente de la Consejería de Familia y Asuntos Sociales de la Comunidad de Madrid (www.comunidad.org); gestionado por Instituto de Trabajo Social y Servicios Sociales (INTRESS), se desarrolla desde el 2004 un proyecto que consiste en la realización del programa de radio comunitaria "Ábrete Camino". La metodología, ba...

  17. An overview and guide: planning instructional radio.

    Science.gov (United States)

    Imhoof, M

    1984-03-01

    Successful instructional radio projects require both comprehensive and complex planning. The instructional radio planning team needs to have knowledge and capabilities in several technical, social, and educational areas. Among other skills, the team must understand radio, curriculum design, the subject matter being taught, research and evaluation, and the environment in which the project operates. Once a basic approach to educational planning has been selected and broad educational goals set, radio may be selected as a cost effective means of achieving some of the goals. Assuming radio is a wise choice, there are still several factors which must be analyzed by a team member who is a radio specialist. The most obvious consideration is the inventory and evaluation of the facilities: studios; broadcast, recording, and transmission equipment; classroom radios; and so on. Capabilities of broadcast personnel are another consideration. Initial radio lessons need to teach the learners how to listen to the radio if they have no previous experience with institutional radio broadcasts. A captive, inschool audience ready to listen to radio instructions requires a different use of the medium than a noncaptive audience. With the noncaptive audience, the educational broadcaster must compete with entertaining choices from other media and popular activities and pastimes of the community. The most complex knowledge and analysis required in planning instructional radio concerns the relationship of the content to the medium. Environmental factors are important in planning educational programs. The physical environment may present several constraints on the learning experience and the use of radio. The most obvious is the effect of climate and terrain on the quality of radio reception. The physical environment is easily studied through experience in the target area, but this knowledge plays a significant role in designing effective learning materials for specific learners. Social

  18. Cognitive Radio Networks for Tactical Wireless Communications

    Science.gov (United States)

    2014-12-01

    three layers of the OSI protocol stack, the physical layer (layer 1) through the network layer (layer 3). The basic waveform, or common base of...radio technologies. It is organized in a network of CR nodes comprised of USRP modules. These nodes may be connected via RF switch matrix that models ...radio network , new modelling , simulation and evaluation capabilities are required. A phased introduction of cognitive radio technologies is

  19. REVIEW OF IMPROVEMENTS IN RADIO FREQUENCY PHOTONICS

    Science.gov (United States)

    2017-09-01

    AFRL-RY-WP-TR-2017-0156 REVIEW OF IMPROVEMENTS IN RADIO FREQUENCY PHOTONICS Preetpaul S. Devgan RF/EO Subsystems Branch Aerospace Components...TITLE AND SUBTITLE REVIEW OF IMPROVEMENTS IN RADIO FREQUENCY PHOTONICS 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER N/A...number 88ABW-2017-4071, Clearance Date 23 August 2017. Report contains color. 14. ABSTRACT Radio Frequency (RF) photonics can be used for multiple

  20. Flattening and radio emission among elliptical galaxies

    International Nuclear Information System (INIS)

    Disney, M.J.; Sparks, W.B.; Wall, J.V.

    1984-01-01

    In a sample of 132 bright elliptical galaxies it is shown that there is a strong correlation between radio activity and flattening in the sense that radio ellipticals are both apparently and inherently rounder than the average elliptical. Both extended and compact sources are subject to the same correlation. No galaxies with axial ratios below 0.65 are found to be radio emitters. (author)

  1. Coping with Radio Frequency Interference

    Science.gov (United States)

    Lewis, B. M.

    2009-01-01

    The radio spectrum is a finite resource, on which humanity makes many demands. And pressure on it is ever increasing with the development of new technology and ideas for radio services. After all, we all benefit from wifi and cell phones. Radio astronomers have a small percentage of the spectrum allocated to them at octave intervals in the metre-centimetre bands, and at important frequencies, such as that of the 21cm line of HI. Signals from other services, as well as from our own poorly-engineered equipment, sometimes contaminate our bands: these signals constitute RFI. These may totally obliterate the astronomical signal, or, in the case of CLOUDSAT, may be capable of completely destroying a receiver, which introduces us to the new possibility of 'destructive interference'. A geo-stationary satellite can block access to a piece of sky from one site. Good equipment design eliminates self-inflicted interference, while physical separation often provides adequate practical mitigation at many frequencies. However, new observatories end up being located in the West Australian desert or Antarctica. In future they may be on the back side of the Moon. But there is no Earth-bound protection via physical separation against satellite signals. Some mitigation can be achieved by frequent data dumps and the excision of RFI, or by real-time detection and blanking of the receiver, or by more sophisticated algoriths. Astronomers of necessity aim to achieve mitigation via coordination, at the local level, and by participating in spectrum management at the national and international levels. This involves them spending a lot of time in Geneva at the International Telegraphic Union protecting their access to spectrum, and access to clean spectrum from the L3 point and the far side of the Moon.

  2. Investigation of the electromagnetic radiation fields from the Sabborah radio broadcasting station and comparing it with the ICNIRP recommended limits

    International Nuclear Information System (INIS)

    Kharita, M.H.; AboKasem, I.

    2007-04-01

    This study concerns a radio emission base station which is located near Sabborah, about 20 Km in the west of Damascus. The aim of this study is to investigate the level and the distribution of electromagnetic field in the nearby of this station in order to determine the level of its hazardous biological effect on the worker and the people living nearby. This work is based on two main parts: First, a theoretical part which offer the concept of electromagnetic wave, the emission and measurement of electromagnetic field, the hazardous biological effects and the general guideline for limiting the exposure to electromagnetic field recommended by the International Commission on Non-Ionizing Radiation Protection and the would Health Organization. Finally, an Experimental part which presents the realized measurements of electric field using two electric field strength meters, the results and recommendations.(author)

  3. 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 ...

  4. 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  

  5. 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.

  6. Genome Radio Project: Quarterly report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    The process of conducting background research for the programs of the Genome Radio Project is continuing. The most developed of the program ``backgrounders`` have been reviewed by series and program advisors from various fields. Preliminary and background interviews have been conducted with dozens of potential program participants and advisors. Structurally, efforts are being directed toward developing and formalizing the project and series advisor relationships so that the best use can be made of those experts who have offered to assist the project in its presentation of program content. The library of research materials has been expanded considerably, creating a useful resource library for the producers.

  7. Identification of southern radio sources

    International Nuclear Information System (INIS)

    Savage, A.

    1976-01-01

    Identifications are suggested for 32 radio sources from the southern zones of the Parkes 2700 MHz survey, 18 with galaxies, one with a confirmed and 12 with possible quasistellar objects, and one with a supernova remnant in the Large Magellanic Cloud. The identifications were made from the ESO IIa-O quick blue survey plates, the SRC IIIa-J deep survey plates and the Palomar sky survey prints. Accurate optical positions have also been measured for 10 of the objects and for five previously suggested QSOs. (author)

  8. La radio universitaria se mueve

    OpenAIRE

    Gloria Rodríguez Garay

    2015-01-01

    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 informa...

  9. 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

  10. On the performance of cognitive radio networks

    Science.gov (United States)

    Wang, Li; Zhang, Li; Zhang, Shibing

    2017-11-01

    Throughput, delay and collision probability are all the important performance for cognitive radio networks. This paper proposes a state transition model and analyzes the performances of the cognitive radio networks with spectrum sensing and access operate simultaneously and conventional cognitive radio networks. The closed form expressions of the throughput, delay and collision probability in two sensing modes are derived. It is showed that the cognitive radio networks with spectrum sensing and access operate simultaneously has obvious advantage over the conventional one in the throughput, delay and collision probability. Simulation results verify the theoretical analysis.

  11. Radio detection of extensive air showers

    Science.gov (United States)

    Huege, Tim

    2017-12-01

    Radio detection of extensive air showers initiated in the Earth's atmosphere has made tremendous progress in the last decade. Today, radio detection is routinely used in several cosmic-ray observatories. The physics of the radio emission in air showers is well-understood, and analysis techniques have been developed to determine the arrival direction, the energy and an estimate for the mass of the primary particle from the radio measurements. The achieved resolutions are competitive with those of more traditional techniques. In this article, I shortly review the most important achievements and discuss the potential for future applications.

  12. 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

  13. 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.

  14. Gamma-ray burster counterparts - Radio

    International Nuclear Information System (INIS)

    Schaefer, B.E.; Cline, T.L.; Desai, U.D.

    1989-01-01

    Many observers and theorists have suggested that gamma-ray bursters (GRBs) are related to highly magnetized rotating, neutron stars, in which case an analogy with pulsars implies that GRBs would be prodigious emitters of polarized radio emission during quiescence. The paper reports on a survey conducted with the Very Large Array radio telescope of 10 small GRB error regions for quiescent radio emission at wavelengths of 2, 6, and 20 cm. The sensitivity of the survey varied from 0.1 to 0.8 mJy. The observations did indeed reveal four radio sources inside the GRB error regions. 27 refs

  15. 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.

  16. The origin of the X-ray, radio and H I structures in the NGC 5903 galaxy group

    Science.gov (United States)

    O'Sullivan, Ewan; Kolokythas, Konstantinos; Kantharia, Nimisha G.; Raychaudhury, Somak; David, Laurence P.; Vrtilek, Jan M.

    2018-02-01

    The NGC 5903 galaxy group is a nearby (∼30 Mpc) system of ∼30 members, dominated by the giant ellipticals NGC 5903 and NGC 5898. The group contains two unusual structures: a ∼110 kpc long H I filament crossing NGC 5903 and a ∼75 kpc wide diffuse, steep-spectrum radio source of unknown origin that overlaps NGC 5903 and appears to be partly enclosed by the H I filament. Using a combination of Chandra, XMM-Newton, Giant Meterwave Radio Telescope (GMRT) and Very Large Array (VLA) observations, we detect a previously unknown ∼0.65 keV intra-group medium filling the volume within 145 kpc of NGC 5903 and find a loop of enhanced X-ray emission extending ∼35 kpc south-west from the galaxy, enclosing the brightest part of the radio source. The northern and eastern parts of this X-ray structure are also strongly correlated with the southern parts of the H I filament. We determine the spectral index of the bright radio emission to be α _{150}^{612} = 1.03 ± 0.08, indicating a radiative age >360 Myr. We discuss the origin of the correlated radio, X-ray and H I structures, either through an interaction-triggered active galactic nucleus (AGN) outburst with enthalpy 1.8 × 1057 erg, or via a high-velocity collision between a galaxy and the H I filament. While neither scenario provides a complete explanation, we find that an AGN outburst is the most likely source of the principal X-ray and radio structures. However, it is clear that galaxy interactions continue to play an important role in the development of this relatively highly evolved galaxy group. We also resolve the question of whether the group member galaxy ESO 514-3 hosts a double-lobed radio source, confirming that the source is a superposed background AGN.

  17. On the origin of radio core emission in radio-quiet quasars

    OpenAIRE

    Blundell, Katherine; Kuncic, Zdenka

    2007-01-01

    We present a model for the radio emission from radio-quiet quasar nuclei. We show that a thermal origin for the high brightness temperature, flat spectrum point sources (known as radio ``cores'') is possible provided the emitting region is hot and optically-thin. We hence demonstrate that optically-thin bremsstrahlung from a slow, dense disk wind can make a significant contribution to the observed levels of radio core emission. This is a much more satisfactory explanation, particularly for so...

  18. 47 CFR 2.815 - External radio frequency power amplifiers.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false External radio frequency power amplifiers. 2... AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.815 External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power...

  19. 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

  20. 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

  1. 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

  2. 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…

  3. Mean and Extreme Radio Properties of Quasars and the Origin of Radio Emission

    Science.gov (United States)

    Richards, Gordon T.; Kratzer, R.

    2014-01-01

    We explore the evolution of the fraction of radio loud quasars and the mean radio properties of quasars. Although any quasar has only a ~10% chance of being radio loud and the average quasar has a radio luminosity of ~4x10^30 ergs/s/Hz, these properties are strong functions of not only luminosity, redshift, black hole mass, and accretion rate, but also the strength of the accretion disk wind (as characterized by CIV emission line properties). Quasars with higher optical luminosity and/or lower redshift have a higher than average probability of being radio loud, but their median radio luminosity (relative to optical) is much lower than average. We find that, while radio properties of quasars generally cannot be predicted from their optical properties, objects where one expects a strong radiation line driven wind (based on emission line features) have virtually no chance of being radio loud. The redder quasars are in the optical, the more radio flux (relative to optical) they have; this trend holds even for quasars that are not expected to be significantly dust reddened/extincted in the optical. Finally, we consider the radio properties of quasars in the framework of models which describe the radio loud extrema as being due to particularly high spin resulting from second generation mergers and in the context of star formation at lower levels of radio flux. This work was supported by NSF AAG grant 1108798.

  4. Pulsar population synthesis using palfa detections and pulsar search collaboratory discoveries including a wide DNS system and a nearby MSP

    Science.gov (United States)

    Swiggum, Joseph Karl

    Using the ensemble of detections from pulsar surveys, we can learn about the sizes and characteristics of underlying populations. In this thesis, I analyze results from the Pulsar Arecibo L-band Feed Array (PALFA) precursor and Green Bank Telescope 350 MHz Drift Scan surveys; I examine survey sensitivity to see how detections can inform pulsar population models, I look at new ways of including young scientists -- high school students -- in the discovery process and I present timing solutions for students' discoveries (including a nearby millisecond pulsar and a pulsar in a wide-orbit double neutron star system). The PALFA survey is on-going and uses the ALFA 7-beam receiver at 1400 MHz to search both inner and outer Galactic sectors visible from Arecibo (32° ?£? 77° and 168° ?£? 214°) close to the Galactic plane (|b| ? 5°) for pulsars. The PALFA precursor survey observed a subset of this region, (|b| ? 1°) and detected 45 pulsars, including one known millisecond pulsar (MSP) and 11 previously unknown, long-period (normal) pulsars. I assess the sensitivity of the PALFA precursor survey and use the number of normal pulsar and MSP detections to infer the size of each underlying Galactic population. Based on 44 normal pulsar detections and one MSP, we constrain each population size to 107,000+36,000-25,000 and 15,000 +85,000-6,000 respectively with 95% confidence. Based on these constraints, we predict yields for the full PALFA survey and find a deficiency in normal pulsar detections, possibly due to radio frequency interference and/or scintillation, neither of which are currently accounted for in population simulations. The GBT 350 MHz Drift Scan survey collected data in the summer of 2007 while the GBT was stationary, undergoing track replacement. Results discussed here come from ~20% of the survey data, which were processed and donated to the Pulsar Search Collaboratory (PSC). The PSC is a joint outreach program between WVU and NRAO, involving high school

  5. Slow Neighbors: A Search for Nearby Stars With Small Proper Motions

    Science.gov (United States)

    Lepine, Sebastien; Bongiorno, B.; Corin, E.; Halmo, M.; Jordan, C.; Moffett, A. J.; Patton, K.; Shara, M. M.; Wittenberg, A.; Zaiats, M.

    2007-12-01

    We present the results of a search for nearby low mass stars and white dwarfs among proper motion stars identified in the full SUPERBLINK all-sky survey. Over 1 million stars with low proper motions (40 mas/yr < μ < 150 mas/yr), are being sifted through in search of nearby objects with relatively small transverse velocities, which have been much overlooked in the past. We show that our survey will considerably extend the census of low-mass stars and white dwarfs within 100 parsecs of the Sun. In particular, this survey will identify most of the still elusive, slow-moving stars in the Solar Neighborhood (d<33; pc), bringing the local stellar census to near completion. This research has been supported by NSF grant AST 0607757, and by the NSF Research Experience for Undergraduates program.

  6. Underestimating nearby nature: affective forecasting errors obscure the happy path to sustainability.

    Science.gov (United States)

    Nisbet, Elizabeth K; Zelenski, John M

    2011-09-01

    Modern lifestyles disconnect people from nature, and this may have adverse consequences for the well-being of both humans and the environment. In two experiments, we found that although outdoor walks in nearby nature made participants much happier than indoor walks did, participants made affective forecasting errors, such that they systematically underestimated nature's hedonic benefit. The pleasant moods experienced on outdoor nature walks facilitated a subjective sense of connection with nature, a construct strongly linked with concern for the environment and environmentally sustainable behavior. To the extent that affective forecasts determine choices, our findings suggest that people fail to maximize their time in nearby nature and thus miss opportunities to increase their happiness and relatedness to nature. Our findings suggest a happy path to sustainability, whereby contact with nature fosters individual happiness and environmentally responsible behavior.

  7. Low dark matter content of the nearby early-type galaxy NGC 821

    Directory of Open Access Journals (Sweden)

    Samurović S.

    2014-01-01

    Full Text Available In this paper we analyze the kinematics and dynamics of the nearby early-type galaxy NGC 821 based on its globular clusters (GCs and planetary nebulae (PNe. We use PNe and GCs to extract the kinematics of NGC 821 which is then used for the dynamical modelling based on the Jeans equation. We apply the Jeans equation using the Newtonian mass-follows-light approach assuming constant mass-to-light ratio and find that using such an approach we can successfully fit the kinematic data. The inferred constant mass-to-light ratio, 4:2 < M=LB < 12:4 present throughout the whole galaxy, implies the lack of significant amount of dark matter. We also used three different MOND approaches and found that we can fit the kinematic data without the need for additional, dark, component. [Projekat Ministarstva nauke Republike Srbije, br. 176021: Visible and invisible matter in nearby galaxies: theory and observations

  8. Dynamic response of the high flux isotope reactor structure caused by nearby heavy load drop

    International Nuclear Information System (INIS)

    Chang, Shih-Jung.

    1995-01-01

    A heavy load of 50,000 lb is assumed to drop from 10 ft above the bottom of the High Flux Isotope Reactor (HFIR) pool at the loading station. The consequences of the dynamic impact to the bottom slab of the pool and to the nearby HFIR reactor vessel are analyzed by applying the ABAQUS computer code The results show that both the BM vessel structure and its supporting legs are subjected to elastic disturbances only and, therefore, will not be damaged. The bottom slab of the pool, however, will be damaged to about half of the slab thickness. The velocity response spectrum at the concrete floor next to the HFIR vessel as a result of the vibration caused by the impact is obtained. It is concluded, that the damage caused by heavy load drop at the loading station is controlled by the slab damage and the nearby HFIR vessel and the supporting legs will not be damaged

  9. Bayesian detection of radar interference in radio astronomy

    Science.gov (United States)

    Jeffs, Brian D.; Lazarte, Weizhen; Fisher, J. Richard

    2006-06-01

    L-Band observations at the Green Bank Telescope (GBT) and other radio observatories are often made in frequency bands allocated to aviation pulsed radar transmissions. It is possible to mitigate radar contamination of the astronomical signal by time blanking data containing these pulses. However, even when strong direct path pulses and nearby fixed clutter echoes are removed there are still undetected weaker aircraft echoes present which can corrupt the data. In a previous paper we presented an algorithm to improve real-time echo blanking by forming a Kalman filter tracker to follow the path of a sequence of echoes observed on successive radar antenna sweeps. The tracker builds a history which can be used to predict the location of upcoming echoes. We now present details of a new Bayesian detection algorithm which uses this prediction information to enable more sensitive weak pulse acquisition. The developed track information is used to form a spatial prior probability distribution for the presence of the next echoes. Regions with higher probability are processed with a lower detection threshold to pull out low level pulses without increasing the overall probability of false alarm detection. The ultimate result is more complete removal, by blanking the detected pulse, of radar corruption in astronomical observations.

  10. The Triggering and Bias of Radio Galaxies

    Science.gov (United States)

    Brand, K.; Rawlings, S.; Tufts, J.; Hill, G. J.

    2004-10-01

    We present new results on the clustering and three-dimensional distribution of radio galaxies from the Texas-Oxford NVSS Structure (TONS) survey. The TONS survey was constructed to look at the distribution of radio galaxies in a region of moderate (0 ≲ z ≲ 0.5) redshifts by matching NVSS sources with objects in APM catalogues to obtain a sample of optically bright (R ≤ 19.5), radio faint (1.4-GHz flux density S1.4 ≥ 3 mJy) radio galaxies over large areas on the sky. We find that redshift spikes, which represent large concentrations of radio galaxies which trace (≈ 100 Mpc3) super-structures are a common phenomena in these surveys. Under the assumption of quasi-linear structure formation theory and a canonical radio galaxy bias, the structures represent ≈ 4-5σ peaks in the primordial density field and their expected number is low. The most plausible explanation for these low probabilities is an increase in the radio galaxy bias with redshift. To investigate potential mechanisms which have triggered the radio activity in these galaxies -and hence may account for an increase in the bias of this population, we performed imaging studies of the cluster environment of the radio galaxies in super-structure regions. Preliminary results show that these radio galaxies may reside preferentially at the edges of rich clusters. If radio galaxies are preferentially triggered as they fall towards rich clusters then they would effectively adopt the cluster bias.

  11. The Eating Habits of Giants and Dwarfs: Chemo-dynamics of Halo Assembly in Nearby Galaxies

    Science.gov (United States)

    Romanowsky, Aaron J.; SAGES Team

    2012-01-01

    I will present novel results on the halo assembly of nearby galaxies, from dwarfs to the most massive ellipticals, using Subaru imaging and Keck spectroscopy. Field stars, globular clusters, and planetary nebulae are used as wide-field chemo-dynamical tracers, mapping out halo substructures that were previously known and unknown. Comparisons are made with simulations of galaxy formation. Supported by the National Science Foundation Grants AST-0808099, AST-0909237, and AST-1109878.

  12. Analytical Model of Underground Train Induced Vibrations on Nearby Building Structures in Cameroon: Assessment and Prediction

    OpenAIRE

    Lezin Seba MINSILI; He XIA; Robert Medjo EKO

    2013-01-01

    The purpose of this research paper was to assess and predict the effect of vibrations induced by an underground railway on nearby-existing buildings prior to the construction of projected new railway lines of the National Railway Master Plan of Cameroon and after upgrading of the railway conceded to CAMRAIL linking the two most densely populated cities of Cameroon: Douala and Yaoundé. With the source-transmitter-receiver mathematical model as the train-soil-structure interaction model, taking...

  13. Speleogenesis of the Jankova pecina cave and karst in it's nearby vicinity

    OpenAIRE

    Đurović Mirela; Đurović Predrag

    2014-01-01

    This paper provides the insight into morpho-hydrologic characteristics and speleogenesis of the Jankova pećina cave and the evolution of karst in the nearby vicinity. Phases in cave evolution, which represents the alternation of accumulative and erosion processes, were analysed. Clogging of existed conduits during the first accumulative phase leads to displacement of the Janko's creek abyss and formation of another entrance along with new, deeper storaged c...

  14. The phase-space structure of nearby dark matter as constrained by the SDSS

    Science.gov (United States)

    Leclercq, Florent; Jasche, Jens; Lavaux, Guilhem; Wandelt, Benjamin; Percival, Will

    2017-06-01

    Previous studies using numerical simulations have demonstrated that the shape of the cosmic web can be described by studying the Lagrangian displacement field. We extend these analyses, showing that it is now possible to perform a Lagrangian description of cosmic structure in the nearby Universe based on large-scale structure observations. Building upon recent Bayesian large-scale inference of initial conditions, we present a cosmographic analysis of the dark matter distribution and its evolution, referred to as the dark matter phase-space sheet, in the nearby universe as probed by the Sloan Digital Sky Survey main galaxy sample. We consider its stretchings and foldings using a tetrahedral tessellation of the Lagrangian lattice. The method provides extremely accurate estimates of nearby density and velocity fields, even in regions of low galaxy density. It also measures the number of matter streams, and the deformation and parity reversals of fluid elements, which were previously thought inaccessible using observations. We illustrate the approach by showing the phase-space structure of known objects of the nearby Universe such as the Sloan Great Wall, the Coma cluster and the Boötes void. We dissect cosmic structures into four distinct components (voids, sheets, filaments, and clusters), using the Lagrangian classifiers DIVA, ORIGAMI, and a new scheme which we introduce and call LICH. Because these classifiers use information other than the sheer local density, identified structures explicitly carry physical information about their formation history. Accessing the phase-space structure of dark matter in galaxy surveys opens the way for new confrontations of observational data and theoretical models. We have made our data products publicly available.

  15. Nearby galaxies as pointers to a better theory of cosmic evolution.

    Science.gov (United States)

    Peebles, P J E; Nusser, Adi

    2010-06-03

    The great advances in the network of cosmological tests show that the relativistic Big Bang theory is a good description of our expanding Universe. However, the properties of nearby galaxies that can be observed in greatest detail suggest that a better theory would describe a mechanism by which matter is more rapidly gathered into galaxies and groups of galaxies. This more rapid growth occurs in some theoretical ideas now under discussion.

  16. The phase-space structure of nearby dark matter as constrained by the SDSS

    International Nuclear Information System (INIS)

    Leclercq, Florent; Percival, Will; Jasche, Jens; Lavaux, Guilhem; Wandelt, Benjamin

    2017-01-01

    Previous studies using numerical simulations have demonstrated that the shape of the cosmic web can be described by studying the Lagrangian displacement field. We extend these analyses, showing that it is now possible to perform a Lagrangian description of cosmic structure in the nearby Universe based on large-scale structure observations. Building upon recent Bayesian large-scale inference of initial conditions, we present a cosmographic analysis of the dark matter distribution and its evolution, referred to as the dark matter phase-space sheet, in the nearby universe as probed by the Sloan Digital Sky Survey main galaxy sample. We consider its stretchings and foldings using a tetrahedral tessellation of the Lagrangian lattice. The method provides extremely accurate estimates of nearby density and velocity fields, even in regions of low galaxy density. It also measures the number of matter streams, and the deformation and parity reversals of fluid elements, which were previously thought inaccessible using observations. We illustrate the approach by showing the phase-space structure of known objects of the nearby Universe such as the Sloan Great Wall, the Coma cluster and the Boötes void. We dissect cosmic structures into four distinct components (voids, sheets, filaments, and clusters), using the Lagrangian classifiers DIVA, ORIGAMI, and a new scheme which we introduce and call LICH. Because these classifiers use information other than the sheer local density, identified structures explicitly carry physical information about their formation history. Accessing the phase-space structure of dark matter in galaxy surveys opens the way for new confrontations of observational data and theoretical models. We have made our data products publicly available.

  17. Environmental Exposure to Ultrafine Particles inside and nearby a Military Airport

    Directory of Open Access Journals (Sweden)

    Marcello Campagna

    2016-10-01

    Full Text Available Airport activities can contribute to the emission of ultrafine particles (UFPs in the environment. The aim of our study is to assess the airborne levels of UFPs in a military airport and in the surrounding area. Four outdoor air samplings were carried out inside a military airport during flight activities, twelve nearby the military airport, five in an urban area, and one in a rural area. We used a portable Electrical Low Pressure Impactor to detect the particle number size distribution as well as the number concentration. Particles were chemically analyzed by field emission scanning electron microscopy. Inside the military airport, we observed an inverse correlation with distance from flight activities. The median UFP count ranged 3.7 × 103 –2.9 × 104 particles/cm3, and the highest UFP count was 4.0 × 106 particles/cm3 (during the taxi and take-off activities. Nearby the airport, UFP number concentrations were more elevated in the winter season and we did not observe a correlation with flight activities. Our results show a constant presence of UFPs regardless of the flight activities nearby the airport. Other anthropic sources may generate UFP concentrations significantly higher than those generated by airport activities.

  18. Secondary radiation effects during transient events on ITER divertor and nearby hidden components

    Science.gov (United States)

    Hassanein, Ahmed; Sizyuk, Valeryi

    2016-10-01

    The secondary plasma developed as a result of disruptions and ELMs on divertor plate is composed mainly from high-Z divertor materials. This mini-plasma will greatly increase the radiation flux to nearby and hidden components. Our simulations showed significant increase in radiation fluxes and heat loads in the high-Z (i.e., tungsten) generated secondary plasma. These radiations could seriously damage hidden nearby components such as umbrella and dome structure. We have implemented enhanced models in our comprehensive integrated HEIGHTS package for 3D simulation of detailed photon and particle transport in the evolved secondary plasma during instabilities. HEIGHTS can simulate full 3D realistic ITER geometry, including the reflector plate, etc. to assess performance of all components resulting from plasma instabilities. HEIGHTS predicted, for the first time, details of heat loads and temperatures evolution of all nearby components due to transient events. Secondary radiation evolution and expansion cause serious damage to hidden internal components that were not directly exposed to DT plasma. Current ITER divertor design may require changes to mitigate such effects and protect interior components that is hard and costly to repair in case of transient disruptive events. Work is partially supported by Purdue University.

  19. The Influence of Galactic Outflows on the Formation of Nearby Dwarf Galaxies.

    Science.gov (United States)

    Scannapieco; Ferrara; Broadhurst

    2000-06-10

    We show that the gas in growing density perturbations is vulnerable to the influence of winds outflowing from nearby collapsed galaxies that have already formed stars. This suggests that the formation of nearby galaxies with masses less, similar10(9) M( middle dot in circle) is likely to be suppressed, irrespective of the details of galaxy formation. An impinging wind may shock-heat the gas of a nearby perturbation to above the virial temperature, thereby mechanically evaporating the gas, or the baryons may be stripped from the perturbation entirely if they are accelerated to above the escape velocity. We show that baryonic stripping is the most effective of these two processes, because shock-heated clouds that are too large to be stripped are able to radiatively cool within a sound crossing time, limiting evaporation. The intergalactic medium temperatures and star formation rates required for outflows to have a significant influence on the formation of low-mass galaxies are consistent with current observations, but may soon be examined directly via associated distortions in the cosmic microwave background and with near-infrared observations from the Next Generation Space Telescope, which may detect the supernovae from early-forming stars.

  20. NEARBY PLANETARY SYSTEMS AS LENSES DURING PREDICTED CLOSE PASSAGES TO BACKGROUND STARS

    Energy Technology Data Exchange (ETDEWEB)

    Di Stefano, Rosanne; Matthews, James [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lepine, Sebastien [Department of Astrophysics, Division of Physical Sciences, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States)

    2013-07-10

    The Einstein rings and proper motions of nearby stars tend to be large. Thus, every year some foreground stars within a few hundred parsecs of Earth induce gravitational lensing events in background stars. In some of these cases, the events may exhibit evidence of planets orbiting the nearby star. In fact, planets can even be discovered during relatively distant passages. Here, we study the lensing signatures associated with planets orbiting nearby high-proper-motion stars. We find the following. (1) Wide-orbit planets can be detected for all distances of closest approach between the foreground and background stars, potentially producing independent events long before and/or after the closest approach. (2) Close-orbit planets can be detected for intermediate distances of closest approach, producing quasiperiodic signatures that may occur days or weeks before and after the stellar-lens event. (3) Planets in the so-called zone for resonant lensing can significantly increase the magnification when the distance of closest approach is small, making the stellar-lens event easier to detect, while simultaneously providing evidence for planets. Because approaches close enough to allow planets to be detected can be predicted, we can plan observing strategies to take advantage of the theoretical framework built in this paper, which describes the sequence of expected effects in terms of a sequence of detection regimes.

  1. Radio observations confirm young stellar populations in local analogues to z ˜ 5 Lyman break galaxies

    Science.gov (United States)

    Greis, Stephanie M. L.; Stanway, Elizabeth R.; Levan, Andrew J.; Davies, Luke J. M.; Eldridge, J. J.

    2017-09-01

    We present radio observations at 1.5 GHz of 32 local objects selected to reproduce the physical properties of z ˜ 5 star-forming galaxies. We also report non-detections of five such sources in the sub-millimetre. We find a radio-derived star formation rate that is typically half than that derived from H α emission for the same objects. These observations support previous indications that we are observing galaxies with a young dominant stellar population, which has not yet established a strong supernova-driven synchrotron continuum. We stress caution when applying star formation rate calibrations to stellar populations younger than 100 Myr. We calibrate the conversions for younger galaxies, which are dominated by a thermal radio emission component. We improve the size constraints for these sources, compared to previous unresolved ground-based optical observations. Their physical size limits indicate very high star formation rate surface densities, several orders of magnitude higher than the local galaxy population. In typical nearby galaxies, this would imply the presence of galaxy-wide winds. Given the young stellar populations, it is unclear whether a mechanism exists in our sources that can deposit sufficient kinetic energy into the interstellar medium to drive such outflows.

  2. A mildly relativistic radio jet from the otherwise normal type Ic supernova 2007gr.

    Science.gov (United States)

    Paragi, Z; Taylor, G B; Kouveliotou, C; Granot, J; Ramirez-Ruiz, E; Bietenholz, M; van der Horst, A J; Pidopryhora, Y; van Langevelde, H J; Garrett, M A; Szomoru, A; Argo, M K; Bourke, S; Paczyński, B

    2010-01-28

    The class of type Ic supernovae have drawn increasing attention since 1998 owing to their sparse association (only four so far) with long duration gamma-ray bursts (GRBs). Although both phenomena originate from the core collapse of a massive star, supernovae emit mostly at optical wavelengths, whereas GRBs emit mostly in soft gamma-rays or hard X-rays. Though the GRB central engine generates ultra-relativistic jets, which beam the early emission into a narrow cone, no relativistic outflows have hitherto been found in type Ib/c supernovae explosions, despite theoretical expectations and searches. Here we report radio (interferometric) observations that reveal a mildly relativistic expansion in a nearby type Ic supernova, SN 2007gr. Using two observational epochs 60 days apart, we detect expansion of the source and establish a conservative lower limit for the average apparent expansion velocity of 0.6c. Independently, a second mildly relativistic supernova has been reported. Contrary to the radio data, optical observations of SN 2007gr indicate a typical type Ic supernova with ejecta velocities approximately 6,000 km s(-1), much lower than in GRB-associated supernovae. We conclude that in SN 2007gr a small fraction of the ejecta produced a low-energy mildly relativistic bipolar radio jet, while the bulk of the ejecta were slower and, as shown by optical spectropolarimetry, mildly aspherical.

  3. 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

  4. 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.

  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. 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

  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. 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....

  9. Mars' radio spectrum and the flying dust.

    NARCIS (Netherlands)

    Roos-Serote, M.; Stam, D.M.; Fender, R.P.

    2004-01-01

    Mars' radio spectrum at centimeter wavelengths is produced by thermal radiation from the surface and sub-surface. Observations at 2.8 cm made in the 1975 and 1978 show variations of its radio brightness as a function of longitude on the planet (Doherty et al. , ApJ 233, 1979). In addition, an

  10. Nganyi Community Resource Centre: Community radio station ...

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

    2016-05-04

    Nganyi Community Resource Centre: Community radio station broadcasts weather forecasts, climate change news to farmers in Kenya. May 04, 2016. Image ... To boost access, KMS distributed radio handsets to communities with a built-in solar power generator and wind-up system. KMS senior assistant director Samuel ...

  11. Adaptive and Distributed Beamforming for Cognitive Radio

    NARCIS (Netherlands)

    Lian, X.

    2013-01-01

    Cognitive Radio (CR) is an energy efficient technique that is capable of optimizing the premium radio resources, such as power and spectrum. In this thesis, we focus on exploiting spatial diversity for CR. We have adopted two spatial signal processing techniques, i.e., Adaptive Beamforming (ABF) and

  12. 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

  13. Radio Afterglows of Gamma Ray Bursts

    Indian Academy of Sciences (India)

    Gamma ray bursts; radio astronomy. ... 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. ... Indian Institute of Space Science and Technology, Trivandrum 695 547, India.

  14. 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.

  15. Local control of cognitive radio networks

    NARCIS (Netherlands)

    Doerr, C.; Grunwald, D.; Sicker, D.C.

    2009-01-01

    In a network deployment, a cognitive radio will have to perform two fundamental tasks. First, each cognitive radio needs to optimize its internal operation, and second, it needs to derive a configuration that will enable and optimize communication with other nodes in the network. This latter

  16. 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 ...

  17. 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.

  18. 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

  19. 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 ...

  20. Farmer participation in radio campaigns for technology adoption:

    African Journals Online (AJOL)

    Peter Berglez

    =Control. Community; PRC=Participatory Radio Campaign. Source: Farm Radio International, 2011. The above impact data suggest that the more farmers listened to radio campaign programmes, the more they learned or gained new ...

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. The Search for Radio Emission from Exoplanets Using LOFAR Low-Frequency Beam-Formed Observations: Preliminary Results on the 55 CNC System

    Science.gov (United States)

    Turner, Jake; Griessmeier, Jean-Mathias; Zarka, Philippe; Vasylieva, Iana

    2017-05-01

    Detection of radio emission from exoplanets can provide information on the star-planet system that is very difficult or impossible to study otherwise, such as the planet's magnetic field, magnetosphere, rotation period, orbit inclination, and star-planet interactions. Such a detection in the radio domain would open up a whole new field in the study of exoplanets, however, currently there are no confirmed detections of an exoplanet at radio frequencies. In this study, we search for non-thermal radio emission from 55 Cnc, an exoplanetary system with 5 planets. 55 Cnc is among the best targets for this search according to theoretical predictions. We observed for 18 hours with the Low-Frequency Array (LOFAR) in the frequency range 26-73 MHz with full-polarization and and covered 85% of the orbital phase of the innermost planet. During the observations four beams were recorded simultaneously on 55 Cnc, a patch of nearby “empty” sky, the nearby pulsar B0823+26, and a bright radio source in the field. The extra beams make this setup unique since they can be used for control of the telescope gain and to verify that a detection in the exoplanet beam is not a false-positive detection (e.g. ionospheric fluctuations). An automatic pipeline was created to automatically find Radio Frequency Interference (RFI) and to search for emission in the exoplanet beam. Conclusions reached at the time of the meeting, about detection of or upper limit to the planetary signal, will be presented. In the near future, we will apply this observational technique and pipeline to some moreplanetary targets, which were selected on the basis of theoretical predictions.

  7. 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

  8. Broadband Radio Polarimetry of Fornax A. I. Depolarized Patches Generated by Advected Thermal Material from NGC 1316

    Science.gov (United States)

    Anderson, C. S.; Gaensler, B. M.; Heald, G. H.; O’Sullivan, S. P.; Kaczmarek, J. F.; Feain, I. J.

    2018-03-01

    We present observations and analysis of the polarized radio emission from the nearby radio galaxy Fornax A over 1.28–3.1 GHz, using data from the Australia Telescope Compact Array. In this, the first of two associated papers, we use modern broadband polarimetric techniques to examine the nature and origin of conspicuous low-polarization (low-p) patches in the lobes. We resolve the (low-p) patches and find that their low fractional polarization is associated with complicated frequency-dependent interference in the polarized signal generated by Faraday effects along the line of sight (LOS). The low-p patches are spatially correlated with interfaces in the magnetic structure of the lobe, across which the LOS-projected magnetic field changes direction. Spatial correlations with the sky-projected magnetic field orientation and structure in total intensity are also identified and discussed. We argue that the (low-p) patches, along with associated reversals in the LOS magnetic field and other related phenomena, are best explained by the presence of { \\mathcal O }({10}9) {M}ȯ of magnetized thermal plasma in the lobes, structured in shells or filaments, and likely advected from the interstellar medium of NCG 1316 or its surrounding intracluster medium. Our study underscores the power and utility of spatially resolved, broadband, full-polarization radio observations to reveal new facets of flow behaviors and magneto-ionic structure in radio lobes and their interplay with the surrounding environment.

  9. 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

  10. Solar Radio Observations and Space Weather

    Science.gov (United States)

    Magdalenic, Jasmina

    2017-04-01

    Coronal mass ejections and associated shock waves are the most important drivers of disturbed geomagnetic conditions. Therefore, tracking of CMEs and the CME-driven shock waves, and predicting their arrival at the Earth, became one of the frequently addressed topics of the space weather research. Studies of radio emission associated with CME-driven shock waves, so-called type II radio bursts, are of particular interest because radio observations cover a broad frequency domain which enables tracking of the shocks all the way from the low corona to the Earth. Consequently, the shock arrival estimate using the coronal radio emission can be updated once the shock signatures are observed in the interplanetary space. In this presentation I will discuss on how radio observations (both ground based and space based) can be used in the space weather forecasting with focus on the recent results in the radio triangulation studies of type II emission which are bringing the new insight in the causal relationship of the CMEs and associated solar radio emission. I will also present high resolution LOFAR observations of the shock wave signatures which show type II emission in a completely new light and therefore bring new challenges to the shock wave physics.

  11. 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.

  12. 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

  13. Preface: The Evolving ISM in the Milky Way and Nearby Galaxies

    Science.gov (United States)

    Sheth, K.; Noriega-Crespo, A.; Ingalls, J.; Paladini, R.

    2009-01-01

    The fourth Spitzer Science Symposium "The Evolving ISM in the Milky Way and Nearby Galaxies" was held in Pasadena, CA from 2-5 December, 2007. The conference focused on synthesizing recent results for the interstellar medium (ISM) and its interplay with star formation in the Milky Way and nearby galaxies. In the Milky Way and Local Group galaxies we have an unparalleled view of the astrophysics of the interstellar medium, where one can study in detail the spatially-resolved energetics and the complex interplay of physical and chemical processes that govern the ISM. The ISM is both a fossil record of past star formation and evolutionary processes and a natal medium for future star formation.The Spitzer Space Telescope has provided a plethora of exciting results that have revolutionized our understanding of the ISM and star formation, particularly from large programs such as MIPSGAL, GLIMPSE, C2D, etc. How do these new discoveries of the local processes governing the ISM impact our understanding of nearby galaxies? How important are local processes when averaged over an entire galaxy? Legacy programs like SINGS and SAGE are two examples of rich and diverse sets of data for nearby galaxies where such questions may be examined?. ISM physics is the critical ingredient for turning gas and dust diagnostics into information about evolutionary processes such as star formation. The exceptional view of the far-infrared Milky way captured by Spitzer and the extraordinary data gathered from nearby galaxies was the main reason for organizing this conference to synthesize the most recent developments in the coupled fields of the ISM and Nearby Galaxies. Over the three days, we heard invited and contributed talks from over fifty participants. The poster session had over 100 posters and results from nearly a quarter of them were also presented in an abbreviated one to two minute format. The conference also had some firsts. We tried to be as environmentally sensitive as possible by

  14. Substellar objects in nearby young clusters (SONYC). VIII. Substellar population in Lupus 3

    International Nuclear Information System (INIS)

    Mužić, Koraljka; Scholz, Alexander; Geers, Vincent C.; Jayawardhana, Ray; Martí, Belén López

    2014-01-01

    SONYC—Substellar Objects in Nearby Young Clusters—is a survey program to investigate the frequency and properties of substellar objects in nearby star-forming regions. We present a new imaging and spectroscopic survey conducted in the young (∼1 Myr), nearby (∼200 pc) star-forming region Lupus 3. Deep optical and near-infrared images were obtained with MOSAIC-II and NEWFIRM at the CTIO 4 m telescope, covering ∼1.4 deg 2 on the sky. The i-band completeness limit of 20.3 mag is equivalent to 0.009-0.02 M ☉ , for A V ≤ 5. Photometry and 11-12 yr baseline proper motions were used to select candidate low-mass members of Lupus 3. We performed a spectroscopic follow-up of 123 candidates, using VIMOS at the Very Large Telescope, and we identify 7 probable members, among which 4 have spectral type later than M6.0 and T eff ≤ 3000 K, i.e., are probably substellar in nature. Two of the new probable members of Lupus 3 appear underluminous for their spectral class and exhibit emission line spectrum with strong H α or forbidden lines associated with active accretion. We derive a relation between the spectral type and effective temperature: T eff = (4120 ± 175) – (172 ± 26) × SpT, where SpT refers to the M spectral subtype between 1 and 9. Combining our results with the previous works on Lupus 3, we show that the spectral type distribution is consistent with that in other star-forming regions, as well as the derived star-to-brown dwarf ratio of 2.0-3.3. We compile a census of all spectroscopically confirmed low-mass members with spectral type M0 or later.

  15. Substellar objects in nearby young clusters (SONYC). VIII. Substellar population in Lupus 3

    Energy Technology Data Exchange (ETDEWEB)

    Mužić, Koraljka [European Southern Observatory, Alonso de Córdova 3107, Casilla 19, Santiago 19001 (Chile); Scholz, Alexander; Geers, Vincent C. [School of Cosmic Physics, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Jayawardhana, Ray [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Martí, Belén López, E-mail: kmuzic@eso.org [Centro de Astrobiología (INTA-CSIC), Departamento de Astrofísica, P.O. Box 78, E-28261 Villanueva de la Cañada, Madrid (Spain)

    2014-04-20

    SONYC—Substellar Objects in Nearby Young Clusters—is a survey program to investigate the frequency and properties of substellar objects in nearby star-forming regions. We present a new imaging and spectroscopic survey conducted in the young (∼1 Myr), nearby (∼200 pc) star-forming region Lupus 3. Deep optical and near-infrared images were obtained with MOSAIC-II and NEWFIRM at the CTIO 4 m telescope, covering ∼1.4 deg{sup 2} on the sky. The i-band completeness limit of 20.3 mag is equivalent to 0.009-0.02 M {sub ☉}, for A{sub V} ≤ 5. Photometry and 11-12 yr baseline proper motions were used to select candidate low-mass members of Lupus 3. We performed a spectroscopic follow-up of 123 candidates, using VIMOS at the Very Large Telescope, and we identify 7 probable members, among which 4 have spectral type later than M6.0 and T {sub eff} ≤ 3000 K, i.e., are probably substellar in nature. Two of the new probable members of Lupus 3 appear underluminous for their spectral class and exhibit emission line spectrum with strong H{sub α} or forbidden lines associated with active accretion. We derive a relation between the spectral type and effective temperature: T {sub eff} = (4120 ± 175) – (172 ± 26) × SpT, where SpT refers to the M spectral subtype between 1 and 9. Combining our results with the previous works on Lupus 3, we show that the spectral type distribution is consistent with that in other star-forming regions, as well as the derived star-to-brown dwarf ratio of 2.0-3.3. We compile a census of all spectroscopically confirmed low-mass members with spectral type M0 or later.

  16. Atmospheric Waves and Dynamics Beneath Jupiters Clouds from Radio Wavelength Observations

    Science.gov (United States)

    Cosentino, Richard G.; Butler, Bryan; Sault, Bob; Morales-Juberias, Raul; Simon, Amy; De Pater, Imke

    2017-01-01

    We observed Jupiter at wavelengths near 2 cm with the Karl G. Jansky Very Large Array (VLA) in February 2015. These frequencies are mostly sensitive to variations in ammonia abundance and probe between approx. 0.5- 2.0 bars of pressure in Jupiters atmosphere; within and below the visible cloud deck which has its base near 0.7 bars. The resultant observed data were projected into a cylindrical map of the planet with spatial resolution of approx. 1500 km at the equator. We have examined the data for atmospheric waves and observed a prominent bright belt of radio hotspot features near 10 N, likely connected to the same equatorial wave associated with the 5-m hotspots. We conducted a passive tracer power spectral wave analysis for the entire map and latitude regions corresponding to eastward and westward jets and compare our results to previous studies. The power spectra analysis revealed that the atmosphere sampled in our observation (excluding the NEB region) is in a 2-D turbulent regime and its dynamics are predominately governed by the shallow water equations. The Great Red Spot (GRS) is also very prominent and has a noticeable meridional asymmetry and we compare it, and nearby storms, with optical images. We find that the meridional radio profile has a global north-south hemisphere distinction and find correlations of it to optical intensity banding and to shear zones of the zonal wind profile over select regions of latitude. Amateur optical images taken before and after our observation complemented the radio wave- length map to investigate dynamics of the equatorial region in Jupiters atmosphere. We find that two radio hotspots at 2 cm are well correlated with optical plumes in the NEB, additionally revealing they are not the same 5 m hotspot features correlated with optical dark patches between adjacent plumes. This analysis exploits the VLAs upgraded sensitivity and explores the opportunities now possible when studying gas giants, especially atmospheric

  17. ROTATION MEASURES ACROSS PARSEC-SCALE JETS OF FANAROFF-RILEY TYPE I RADIO GALAXIES

    International Nuclear Information System (INIS)

    Kharb, P.; Gabuzda, D. C.; O'Dea, C. P.; Shastri, P.; Baum, S. A.

    2009-01-01

    We present the results of a parsec-scale polarization study of three FRI radio galaxies-3C66B, 3C78, and 3C264-obtained with Very Long Baseline Interferometry at 5, 8, and 15 GHz. Parsec-scale polarization has been detected in a large number of beamed radio-loud active galactic nuclei, but in only a handful of the relatively unbeamed radio galaxies. We report here the detection of parsec-scale polarization at one or more frequencies in all three FRI galaxies studied. We detect Faraday rotation measures (RMs) of the order of a few hundred rad m -2 in the nuclear jet regions of 3C78 and 3C264. In 3C66B, polarization was detected at 8 GHz only. A transverse RM gradient is observed across the jet of 3C78. The inner-jet magnetic field, corrected for Faraday rotation, is found to be aligned along the jet in both 3C78 and 3C264, although the field becomes orthogonal further from the core in 3C78. The RM values in 3C78 and 3C264 are similar to those previously observed in nearby radio galaxies. The transverse RM gradient in 3C78, the increase in the degree of polarization at the jet edge, the large rotation in the polarization angles due to Faraday rotation, and the low depolarization between frequencies suggest that a layer surrounding the jet with a sufficient number of thermal electrons and threaded by a toroidal or helical magnetic field is a good candidate for the Faraday rotating medium. This suggestion is tentatively supported by Hubble Space Telescope optical polarimetry but needs to be examined in a greater number of sources.

  18. Solar radio helping people to help themselves

    Energy Technology Data Exchange (ETDEWEB)

    Brown, C.

    1999-07-01

    This article reports on the use of solar technology to bring radio to remote rural areas in the developing world. Details of the UK based BioDesign's Solar Radio and field tests in Africa, Central America, Asia and recently Madagascar are given, and the training of science teachers in rural areas under a scheme devised by the Dodwell Trust in collaboration with the Madagascar government is outlined. The interest displayed by aid organisations in solar radio, and the need to teach local people about new techniques are discussed.

  19. 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....

  20. 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'.

  1. High power radio frequency attenuation device

    Science.gov (United States)

    Kerns, Quentin A.; Miller, Harold W.

    1984-01-01

    A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

  2. New radio observations of NGC1275

    International Nuclear Information System (INIS)

    Pedlar, A.; Perley, R.; Crane, P.; Harrison, B.; Davies, R.D.

    1986-01-01

    VLA maps are presented for NGC1275 at 20 cm, with resolutions ranging from 1 to 40 arcsec. Over the central 30 arcsec there is evidence for collimated ejection at position angle -160 deg. Outside this region the radio structure bends rapidly by approximately 90 deg before merging into the 10-arcmin radio halo. It is suggested that models of pressure-driven accretion flows should take into account the presence of the relativistic gas which is responsible for the radio halo. 14 references

  3. Radio Imaging of Envelopes of Evolved Stars

    Science.gov (United States)

    Cotton, Bill

    2018-04-01

    This talk will cover imaging of stellar envelopes using radio VLBI techniques; special attention will be paid to the technical differences between radio and optical/IR interferomery. Radio heterodyne receivers allow a straightforward way to derive spectral cubes and full polarization observations. Milliarcsecond resolution of very bright, i.e. non thermal, emission of molecular masers in the envelopes of evolved stars can be achieved using VLBI techniques with baselines of thousands of km. Emission from SiO, H2O and OH masers are commonly seen at increasing distance from the photosphere. The very narrow maser lines allow accurate measurements of the velocity field within the emitting region.

  4. New radio meteor detecting and logging software

    Science.gov (United States)

    Kaufmann, Wolfgang

    2017-08-01

    A new piece of software ``Meteor Logger'' for the radio observation of meteors is described. It analyses an incoming audio stream in the frequency domain to detect a radio meteor signal on the basis of its signature, instead of applying an amplitude threshold. For that reason the distribution of the three frequencies with the highest spectral power are considered over the time (3f method). An auto notch algorithm is developed to prevent the radio meteor signal detection from being jammed by a present interference line. The results of an exemplary logging session are discussed.

  5. HII regions in IC 1613: The ISM in a nearby dwarf irregular galaxy

    Science.gov (United States)

    Price, Jill S.; Mason, Stephen F.; Gullixson, Craig A.

    1990-01-01

    IC 1613, a nearby (725 kpc distant) dwarf irregular galaxy, has always been known to contain large, ring-shaped HII regions in its northeast corner. A new H alpha image has been obtained using the Bell Labs Charge Coupled Device (CCD) camera, an RCA 320 X 512 pixel-thinned, back-illuminated CCD, an H alpha filter of central wavelength 6562 A and width (full width half maximum) of 30 A, and the 42 inch telescope at Lowell Observatory. The low resolution images exhibit many new, faint features.

  6. Exploring the CO/CN line ratio in nearby galaxies with the ALMA archive

    Science.gov (United States)

    Wilson, Christine D.

    2018-03-01

    We describe an archival project using Cycle 0 data from the Atacama Large Millimeter/submilleter Array to survey the CO/CN line ratio in 17 nearby galaxies. CN is an interesting molecule that traces dense gas exposed to ultraviolet radiation and its N = 1 - 0 lines can be observed simultaneously with the CO J = 1 - 0 line. We identify 8 galaxies with distances starburst-dominated regions, which may be in conflict with models of molecular abundances in X-ray dominated regions.

  7. Surge voltages and currents into a customer due to nearby lightning

    Energy Technology Data Exchange (ETDEWEB)

    Ametani, Akihiro; Matsuoka, Kae [Power System Analysis Laboratory, Doshisha University, Kyo-tanabe, Kyoto 610-0321 (Japan); Omura, Hiroshi; Nagai, Yoshiyuki [Power Engineering R and D Center, Kansai Electric Power Co., Amagasaki, Osaka 661-0794 (Japan)

    2009-03-15

    This paper presents experimental results of lightning surges incoming into a customer due to lightning to an antenna of the customer, a pole and a ground nearby the customer, and briefly discusses lightning current distribution in the customer, a distribution line and a telephone line. Based on experimental results, modeling of each component is explained, and EMTP simulations are carried out. The ground voltage rise is represented by a mutual resistance between grounding electrodes. EMTP simulation results have been observed to agree qualitatively with the measured results, and it becomes possible to investigate lightning surges and current distribution in a customer by an EMTP simulation. (author)

  8. PICTURE-C: A NASA Balloon Mission to Directly Image Exozodiacal Dust Around Nearby Stars

    Science.gov (United States)

    Mendillo, Christopher; Hewawasam, Kuravi; Howe, Glenn A.; Martel, Jason; Finn, Susanna; Cook, Timothy; Chakrabarti, Supriya

    2018-01-01

    The Planetary Imaging Concept Testbed Using a Recoverable Experiment - Coronagraph (PICTURE-C) mission will directly image debris disks and exozodiacal dust around nearby stars from a high-altitude balloon using a vector vortex coronagraph (VVC). The mission will consist of two flights, the first in September, 2018 and the second in September, 2019. The second flight will also include a microwave kinetic inductance detector (MKID) to provide spectral imaging. We present a progress report for the mission, which recently completed its critical design review. This will include a description of recent major optical design changes that occurred due to a change in the deformable mirror vendor.

  9. Inductive coupling between overhead power lines and nearby metallic pipelines. A neural network approach

    Directory of Open Access Journals (Sweden)

    Levente Czumbil

    2015-12-01

    Full Text Available The current paper presents an artificial intelligence based technique applied in the investigation of electromagnetic interference problems between high voltage power lines (HVPL and nearby underground metallic pipelines (MP. An artificial neural network (NN solution has been implemented by the authors to evaluate the inductive coupling between HVPL and MP for different constructive geometries of an electromagnetic interference problem considering a multi-layer soil structure. Obtained results are compared to solutions provided by a finite element method (FEM based analysis and considered as reference. The advantage of the proposed method yields in a simplified computation model compared to FEM, and implicitly a lower computational time.

  10. Optical observations of the nearby galaxy IC342 with narrow band [SII] and Hα filters. I

    Directory of Open Access Journals (Sweden)

    Vučetić M.M.

    2013-01-01

    Full Text Available We present observations of a portion of the nearby spiral galaxy IC342 using narrow band [SII] and Hα filters. These observations were carried out in November 2011 with the 2m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper we report coordinates, diameters, Hα and [SII] fluxes for 203 HII regions detected in two fields of view in IC342 galaxy. The number of detected HII regions is 5 times higher than previously known in these two parts of the galaxy. [Projekat Ministarstva nauke Republike Srbije, br. 176005: Emission nebulae: structure and evolution

  11. The structure of nearby clusters of galaxies Hierarchical clustering and an application to the Leo region

    CERN Document Server

    Materne, J

    1978-01-01

    A new method of classifying groups of galaxies, called hierarchical clustering, is presented as a tool for the investigation of nearby groups of galaxies. The method is free from model assumptions about the groups. The scaling of the different coordinates is necessary, and the level from which one accepts the groups as real has to be determined. Hierarchical clustering is applied to an unbiased sample of galaxies in the Leo region. Five distinct groups result which have reasonable physical properties, such as low crossing times and conservative mass-to-light ratios, and which follow a radial velocity- luminosity relation. Only 4 out of 39 galaxies were adopted as field galaxies. (27 refs).

  12. EnviroAtlas - Acres of crops that have no nearby pollinator habitat for the Conterminous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset is a summary of crop acres without nearby pollinator habitat. Pollination habitat here is defined as trees (fruit, nut, deciduous, and evergreen). Crops...

  13. 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.

  14. 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%.

  15. 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.

  16. La radio generalista en la red: un nuevo modelo para la radio tradicional

    OpenAIRE

    Martínez Costa, María del Pilar; Moreno, Elsa; Amoedo, Avelino

    2012-01-01

    La radio generalista enfrenta un cambio sustancial en la denominada sociedad de lacomunicación interactiva. Internet –como catalizador del proceso de convergenciadigital– plantea un nuevo entorno comunicativo para la radio, que exige repensar lasestrategias, los conceptos y la dinámica tradicional con la que viene trabajando elmedio radiofónico. La radio generalista en la red adquiere una dimensión informativanovedosa que implica un modelo narrativo, productivo y programático original paraate...

  17. A Software Radio Implementation of Centralized MAC Protocol for Cognitive Radio Networks

    OpenAIRE

    DELFINO Alessandro; GORATTI LEONARDO; GIULIANI RAIMONDO; OLIVERI Franco; BALDINI Gianmarco

    2011-01-01

    In the past decade the cognitive radio paradigm received great attention from academia and industry as a promising approach to solve the spectrum shortage problem. In spite of the intense research activity in the field of cognitive radio, we still register a limited number of network implementations based upon the cognitive radio principles. In this work, we present the design and implementation of a proprietary medium access control protocol that we have conjectured using Standard ECMA...

  18. Binary Black Holes, Accretion Disks and Relativistic Jets: Photocenters of Nearby AGN and Quasars

    Science.gov (United States)

    Wehrle, Ann E.; Jones, Dayton L.; Meier, David L.; Piner, B. Glenn; Unwin, Stephen C.

    2004-01-01

    One of the most challenging questions in astronomy today is to understand the origin, structure, and evolution of the central engines in the nuclei of quasars and active galaxies (AGNs). The favoured theory involves the activation of relativistic jets from the fueling of a supermassive black hole through an accretion disk. In some AGN an outer optically thick, dusty torus is seen orbiting the black hole system. This torus is probably related to an inner accretion disk - black hole system that forms the actual powerhouse of the AGN. In radio-loud AGN two oppositely-directed radio jets are ejected perpendicular to the torus/disk system. Although there is a wealth of observational data on AGN, some very basic questions have not been definitively answered. The Space Interferometry Mission (SIM) will address the following three key questions about AGN. 1) Does the most compact optical emission from an AGN come from an accretion disk or from a relativistic jet? 2) Does the separation of the radio core and optical photocenter of the quasars used for the reference frame tie, change on the timescales of their photometric variability, or is the separation stable at the level of a few microarcseconds? 3) Do the cores of galaxies harbor binary supermassive black holes remaining from galaxy mergers? It is not known whether such mergers are common, and whether binaries would persist for a significant time.

  19. Short range radio locator system

    Science.gov (United States)

    McEwan, T.E.

    1996-12-31

    A radio location system comprises a wireless transmitter that outputs two megahertz period bursts of two gigahertz radar carrier signals. A receiver system determines the position of the transmitter by the relative arrival of the radar bursts at several component receivers set up to have a favorable geometry and each one having a known location. One receiver provides a synchronizing gating pulse to itself and all the other receivers. The rate of the synchronizing gating pulse is slightly offset from the rate of the radar bursts themselves, so that each sample collects one finely-detailed piece of information about the time-of-flight of the radar pulse to each receiver each pulse period. Thousands of sequential pulse periods provide corresponding thousand of pieces of information about the time-of-flight of the radar pulse to each receiver, in expanded, not real time. Therefore the signal processing can be done with relatively low-frequency, inexpensive components. A conventional microcomputer is then used to find the position of the transmitter by geometric triangulation based on the relative time-of-flight information. 5 figs.

  20. Aliphatic Nucleophilic Radio-fluorination

    International Nuclear Information System (INIS)

    Roeda, D.; Dolle, F.

    2010-01-01

    In this review we are looking at some aspects of nucleophilic aliphatic radio-fluorination, notably the labelled fluoride source, design aspects, the leaving group and the solvent. It should be clear that there is more to this branch of radiolabelling than one would suspect from the frequently used standard tosylate replacement with kryptofix/[ 18 F]fluoride in acetonitrile or DMSO. Competitive elimination can be a serious problem that can affect both yield and purification. De-protection of sensitive groups after radiolabelling and its possible side reactions can complicate purification. The right choice of leaving group and protecting groups may be crucial. Newer developments such as the use of tertiary alcohols or ionic liquids as solvents, long-chain poly-fluorinated sulphonate leaving groups facilitating fluorous solid phase extraction, or immobilisation of the precursor on a solid phase support may help to solve these problems, for example the longstanding problems with [ 18 F]FLT, whereas older concepts such as certain cyclic reactive entities for ring opening or even an abandoned reagent as [ 18 F]DAST should not be forgotten. (authors)

  1. Information Management: Military Affiliate Radio System (MARS)

    National Research Council Canada - National Science Library

    1986-01-01

    .... It describes a program sponsored by the Department of Defense and supported by the Department of the Army in which military installations, military units, clubs, and volunteer licensed amateur radio...

  2. Video Conferencing Using Packet Radio Technology

    National Research Council Canada - National Science Library

    Nimitbunanan, Narongchai

    1997-01-01

    .... Video-conferencing is a highly effective means to deliver information since it is interactive. This thesis studies the packet-radio- networking technology that can be used to support video-conferencing applications...

  3. Software Defined Multiband EVA Radio, Phase I

    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...

  4. Reconfigurable, Cognitive Software Defined Radio, Phase II

    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...

  5. Software Defined Multiband EVA Radio, Phase II

    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. Cosmological measurements with forthcoming radio continuum surveys

    CSIR Research Space (South Africa)

    Raccanelli, A

    2012-08-01

    Full Text Available spectrum and supernovae (SNe). We show that near-future radio surveys will bring complementary measurements to other experiments, probing different cosmological volumes and having different systematics. Our results show that the unprecedented sky coverage...

  7. 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...

  8. Solar energetic particles and radio burst emission

    Directory of Open Access Journals (Sweden)

    Miteva Rositsa

    2017-01-01

    Full Text Available We present a statistical study on the observed solar radio burst emission associated with the origin of in situ detected solar energetic particles. Several proton event catalogs in the period 1996–2016 are used. At the time of appearance of the particle origin (flare and coronal mass ejection we identified radio burst signatures of types II, III and IV by inspecting dynamic radio spectral plots. The information from observatory reports is also accounted for during the analysis. The occurrence of solar radio burst signatures is evaluated within selected wavelength ranges during the solar cycle 23 and the ongoing 24. Finally, we present the burst occurrence trends with respect to the intensity of the proton events and the location of their solar origin.

  9. Solar energetic particles and radio burst emission

    Science.gov (United States)

    Miteva, Rositsa; Samwel, Susan W.; Krupar, Vratislav

    2017-12-01

    We present a statistical study on the observed solar radio burst emission associated with the origin of in situ detected solar energetic particles. Several proton event catalogs in the period 1996-2016 are used. At the time of appearance of the particle origin (flare and coronal mass ejection) we identified radio burst signatures of types II, III and IV by inspecting dynamic radio spectral plots. The information from observatory reports is also accounted for during the analysis. The occurrence of solar radio burst signatures is evaluated within selected wavelength ranges during the solar cycle 23 and the ongoing 24. Finally, we present the burst occurrence trends with respect to the intensity of the proton events and the location of their solar origin.

  10. Reconfigurable, Cognitive Software Defined Radio, Phase I

    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...

  11. Reconfigurable, Digital EVA Radio, Phase II

    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,...

  12. Improving highway advisory radio predictability and performance

    Science.gov (United States)

    2011-01-01

    Highway Advisory Radio (HAR) stations, sometimes referred to as Travelers Information Stations (TIS), : allow highway agencies to broadcast important messages about traffic, weather and roadway conditions to : motorists. Caltrans has deployed HAR ...

  13. A comparative study of cognitive radio platforms

    CSIR Research Space (South Africa)

    Masonta, MT

    2012-10-01

    Full Text Available Cognitive radio (CR) technology has become one of the buzzwords within the wireless communications community over the past 12 years. Its ability to learn, decide and adapt to the external environment made CR attractive to regulators, researchers...

  14. 47 CFR 20.9 - Commercial mobile radio service.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Commercial mobile radio service. 20.9 Section... COMMERCIAL MOBILE RADIO SERVICES § 20.9 Commercial mobile radio service. (a) The following mobile services shall be treated as common carriage services and regulated as commercial mobile radio services...

  15. 78 FR 266 - Radio Broadcasting Services; Maysville, GA

    Science.gov (United States)

    2013-01-03

    ...-270; RM-11676; DA 12-2024] Radio Broadcasting Services; Maysville, GA AGENCY: Federal Communications... Review Act, see 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting...: PART 73--RADIO BROADCAST SERVICES 0 1. The authority citation for part 73 continues to read as follows...

  16. 78 FR 4078 - Radio Broadcasting Services; Hebbronville, TX

    Science.gov (United States)

    2013-01-18

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Hebbronville, TX AGENCY: Federal Communications... Review Act, see 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting...: PART 73--RADIO BROADCAST SERVICES 0 1. The authority citation for part 73 continues to read as follows...

  17. 47 CFR 80.1153 - Station log and radio watches.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Station log and radio watches. 80.1153 Section... SERVICES STATIONS IN THE MARITIME SERVICES Voluntary Radio Installations General § 80.1153 Station log and radio watches. (a) Licensees of voluntary ships are not required to maintain radio station logs. (b...

  18. 47 CFR 0.484 - Amateur radio operator examinations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Amateur radio operator examinations. 0.484....484 Amateur radio operator examinations. Generally, examinations for amateur radio operation licenses... FCC conducts examinations for amateur radio operator licenses, they shall take place at locations and...

  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. Survival and reproduction of radio-marked adult spotted owls.

    Science.gov (United States)

    C.C. Foster; E.D. Forsman; E.C. Meslow; G.S. Miller; J.A. Reid; F.F. Wagner; A.B. Carey; J.B. Lint

    1992-01-01

    We compared survival, reproduction, and body mass of radio-marked and non radio-marked spotted owls (Strix occidentalis) to determine if backpack radios influenced reproduction or survival. In most study areas and years, there were no differences (P > 0.05) in survival of males and females or in survival of radio-marked versus banded owls. There...

  1. Analytical Model of Underground Train Induced Vibrations on Nearby Building Structures in Cameroon: Assessment and Prediction

    Directory of Open Access Journals (Sweden)

    Lezin Seba MINSILI

    2013-11-01

    Full Text Available The purpose of this research paper was to assess and predict the effect of vibrations induced by an underground railway on nearby-existing buildings prior to the construction of projected new railway lines of the National Railway Master Plan of Cameroon and after upgrading of the railway conceded to CAMRAIL linking the two most densely populated cities of Cameroon: Douala and Yaoundé. With the source-transmitter-receiver mathematical model as the train-soil-structure interaction model, taking into account sub-model parameters such as type of the train-railway system, typical geotechnical conditions of the ground and the sensitivity of the nearby buildings, the analysis is carried out over the entire system using the dynamic finite element method in the time domain. This subdivision of the model is a powerful tool that allows to consider different alternatives of sub-models with different characteristics, and thus to determine any critical excessive vibration impact. Based on semi-empirical analytical results obtained from presented models, the present work assesses and predicts characteristics of traffic-induced vibrations as a function of time duration, intensity and vehicle speed, as well as their influence on buildings at different levels.

  2. Rock outcrops redistribute water to nearby soil patches in karst landscapes.

    Science.gov (United States)

    Wang, Dian-Jie; Shen, You-Xin; Huang, Jin; Li, Yu-Hui

    2016-05-01

    The emergence of rock outcrops is very common in terrestrial ecosystems. However, few studies have paid attention to their hydrological role in the redistribution of precipitation, especially in karst ecosystems, in which a large proportion of the surface is occupied by carbonate outcrops. We collected and measured water received by outcrops and its subsequent export to the soil in a rock desertification ecosystem, an anthropogenic forest ecosystem, and a secondary forest ecosystem in Shilin, China. The results indicated that outcrops received a large amount of water and delivered nearly half of it to nearby soil patches by means of runoff. No significant difference was found in the ratio of water received to that exported to the soil by outcrops among the three ecosystems annually. When the outcrop area reaches 70 % of the ground surface, the amount of water received by soil patches from rock runoff will equal that received by precipitation, which means that the soil is exposed to twice as much precipitation. This quantity of water can increase water input to nearby soil patches and create water content heterogeneity among areas with differing rock emergence.

  3. Isopod fauna, excluding Epicaridea, from the Strait of Gibraltar and nearby areas (Southern Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    José Castelló

    2001-09-01

    Full Text Available A total of 42 isopod species from the Strait of Gibraltar and nearby areas were found, including the first record of Munna fabricii, Monodanthura maroccana, Campecopea hirsute, and Natatolana gallica from the Mediterranean; Synisoma nadejda and Uromunna petiti from the Atlantic; and Munna fabricii, Uromunna petiti, Monodanthura maroccana, Stellanthura cryptobia and Natatolana gallica from the Iberian waters. This article includes the previous records from the Iberian waters for all the species. The greatest number of species were found in Tarifa (16 species, located in the transition zone between the Atlantic Ocean and the Mediterranean Sea. According to depth, the distribution of species was as follows: 18 species were collected in the intertidal zone, mostly Dynamene edwardsi and Ischyromene lacazei; 33 species were found between 1 and 10 m, 13 species were found between 11 and 20 m, and 6 species were found between 21 and 28 m, mostly Janira maculosa. According to habitat, 16 species were collected on soft bottoms, 2 species on Zostera, and 22 species on algae substrata, mostly Halopteris, Asparagopsis and Cystoseira. The most diverse genus was Cymodoce (5 species. This paper contributes to the taxonomic, faunistic and biogeographical knowledge of the benthic communities from the Strait of Gibraltar and nearby areas.

  4. NEW NEIGHBORS: PARALLAXES OF 18 NEARBY STARS SELECTED FROM THE LSPM-NORTH CATALOG

    International Nuclear Information System (INIS)

    Lepine, Sebastien; Shara, Michael M.; Thorstensen, John R.; Rich, R. Michael

    2009-01-01

    We present astrometric parallaxes for 18 suspected nearby stars selected from the LSPM-north proper motion catalog. 16 objects are confirmed to be main-sequence M dwarfs within 16 pc of the Sun, including three stars (LSPM J0011+5908, LSPM J0330+5413, and LSPM J0510+2714) which lie just within the 10 pc horizon. Two other targets (LSPM J1817+1328, LSPM J2325+1403) are confirmed to be nearby white dwarfs at distances of 14 and 22 pc, respectively. One of our targets, the common proper motion pair LSPM J0405+7116E + LSPM J0405+7116W, is revealed to be a triple system, with the western component resolved into a pair of 16th magnitude stars (LSPM J0405+7116W-A and LSPM J0405+7116W-B) with a 0.7 ±0.''1 angular separation. We find two stars (LSPM J1314+1320 and LSPM J1757+7042) to be significantly overluminous for their colors, and conclude that these may be unresolved doubles/multiples.

  5. Rave: The Age-metallicity-velocity Relation In The Nearby Disk

    Science.gov (United States)

    Anguiano, Borja; Freeman, K.; Steinmetz, M.; de Boer, E. Wylie; RAVE Collaboration

    2010-01-01

    A fundamental issue in our understanding of the evolution of the Milky Way is the existence of an Age-Metallicity-Velocity relation (AMVR) in the nearby disk. However there are still remarkable differences in the form of this relation (e.g Twarog 1980, Meusinger et al. 1991, Edvardsson et al. 1993, Rocha-Pinto et al. 2000, Quillen & Garnett 2000, Feltzing et al. 2001, Holmberg et al. 2007). Moreover we have found considerable differences between the methods and the populations we use for dating the Galaxy and how a selection of the lowest errors in age introduce bias in the relation. Following this idea we are working in a new derivation of the AMVR. We are using a carefully selected subgiants stars from RAVE and Geneva-Copenhagen surveys. RAVE provides accurate kinematics and a first estimate of metallicity, temperature and gravity. Follow-up observations allow us to obtain accurate fundametal parameters and individual abundances in order to derive reliable ages and generate an AMVR for the nearby disk.

  6. On the Age-Metallicity-Velocity Relation in the Nearby Disk Using the RAVE Survey

    Science.gov (United States)

    Anguiano, Borja; Freeman, Kenneth C.; Steinmetz, Matthias; de Boer, Elizabeth Wylie

    The age-metallicity-velocity relation (AMVR) in the nearby disk is a fundamental issue in our understanding of the evolution of the Milky Way. However, there are still major differences between various versions of this relation (e.g., Twarog 1980, ApJ, 242, 242,Meusinger et al. 1991, A&A, 245, 57, Edvardsson et al. 1993, A&A, 275, 101, Rocha-Pinto et al. 2000, A &A, 358, 850,Quillen & Garnett 2001, Galaxy Disks and Disk Galaxies, ASP, San Francisco, CA, vol. 230, p. 87, Feltzing et al. 2001, A&A, 377,911, and Holmberg et al. 2007, A&A, 475, 519). Also, we have found considerable differences between different methods forage-dating stellar populations and have shown how different methods introduce bias in the AMVR. We are therefore working in a new derivation of these possible relations in the nearby disk, using a carefully selected sample of subgiants stars from RAVE and Geneva-Copenhagen surveys. RAVE provides accurate kinematics and a first estimate of metallicity, temperature, and gravity. Follow-up observations allow us to obtain accurate fundamental parameters via spectrophotometry and highresolution spectroscopy in order to derive reliable ages and generate an AMVR for stars of the Galactic disk.

  7. More Than Filaments and Cores: Statistical Study of Structure Formation and Dynamics in Nearby Molecular Clouds

    Science.gov (United States)

    Chen, How-Huan; Goodman, Alyssa

    2018-01-01

    In the past decade, multiple attempts at understanding the connection between filaments and star forming cores have been made using observations across the entire epectrum. However, the filaments and the cores are usually treated as predefined--and well-defined--entities, instead of structures that often come at different sizes, shapes, with substantially different dynamics, and inter-connected at different scales. In my dissertation, I present an array of studies using different statistical methods, including the dendrogram and the probability distribution function (PDF), of structures at different size scales within nearby molecular clouds. These structures are identified using observations of different density tracers, and where possible, in the multi-dimensional parameter space of key dynamic properties--the LSR velocity, the velocity dispersion, and the column density. The goal is to give an overview of structure formation in nearby star-forming clouds, as well as of the dynamics in these structures. I find that the overall statistical properties of a larger structure is often the summation/superposition of sub-structures within, and that there could be significant variations due to local physical processes. I also find that the star formation process within molecular clouds could in fact take place in a non-monolithic manner, connecting potentially merging and/or transient structures, at different scales.

  8. Discovery of Temperate Earth-Sized Planets Transiting a Nearby Ultracool Dwarf Star

    Science.gov (United States)

    Jehin, Emmanuel; Gillon, Michael; Lederer, Susan M.; Delrez, Laetitia; De Wit, Julien; Burdanov, Artem; Van Grootel, Valerie; Burgasser, Adam; Triaud, Amaury; Demory, Brice-Olivier; hide

    2016-01-01

    We report the discovery of three short-period Earth-sized planets transiting a nearby ultracool dwarf star using data collected by the Liège TRAPPIST telescope, located in la Silla (Chile). TRAPPIST-1 is an isolated M8.0+/-0.5-type dwarf star at a distance of 12.0+/-0.4 parsecs as measured by its trigonometric parallax, with an age constrained to be > 500 Myr, and with a luminosity, mass, and radius of 0.05%, 8% and 11.5% those of the Sun, respectively. The small size of the host star, only slightly larger than Jupiter, translates into Earth-like radii for the three discovered planets, as deduced from their transit depths. The inner two planets receive four and two times the irradiation of Earth, respectively, placing them close to the inner edge of the habitable zone of the star. Several orbits remain possible for the third planet based on our current data. The infrared brightness of the host star combined with its Jupiter-like size offer the possibility of thoroughly characterizing the components of this nearby planetary system.

  9. Continuing a Snapshot Survey of the Sites of Recent, Nearby Supernovae: Cycles 25 & 26

    Science.gov (United States)

    Filippenko, Alex

    2017-08-01

    During the past two decades, robotic (or highly automated) searches for supernovae (SNe), including our Lick Observatory Supernova Search (LOSS), have found over 1000 SNe, many of them in quite nearby galaxies (cz < 4000 km/s). Most of the objects were discovered before maximum brightness, and have follow-up photometry and spectroscopy; they include some of the best-studied SNe to date. We propose to continue our successful program of imaging the sites of some of these nearby objects, to obtain late-time photometry that will help reveal the origin of their lingering energy. We will also search for possible stellar remnants of Type Iax SNe, an intriguing new possibility. Moreover, the images will provide high-resolution information on the local environments of SNe that are far superior to what we can procure from the ground. For example, we will obtain color-magnitude diagrams of stars in these SN sites, to constrain the reddening and SN progenitor masses. We will search for light echoes around SNe, an important clue to their progenitor systems. We also propose to image some SN impostors - faint SNe IIn with massive progenitors - to verify whether they are indeed superoutbursts of luminous blue variables and survived the explosions, or a new/weak class of massive-star explosions. Our proposed snapshots in Cycles 25 and 26 will complement and extend the set of targets we imaged in previous Cycles under this program.

  10. Continuing a Snapshot Survey of the Sites of Recent, Nearby Supernovae

    Science.gov (United States)

    Filippenko, Alex

    2015-10-01

    During the past decade, robotic (or nearly robotic) searches for supernovae (SNe), most notably our Lick Observatory Supernova Search (LOSS), have found hundreds of SNe, many of them in quite nearby galaxies (cz < 4000 km/s). Most of the objects were discovered before maximum brightness, and have follow-up photometry and spectroscopy; they include some of the best-studied SNe to date. We propose to continue our successful program of imaging the sites of some of these nearby objects, to obtain late-time photometry that will help reveal the origin of their lingering energy. We will also search for possible stellar remnants of Type Iax SNe, an intriguing new possibility. Moreover, the images will provide high-resolution information on the local environments of SNe that are far superior to what we can procure from the ground. For example, we will obtain color-magnitude diagrams of stars in these SN sites, to constrain the reddening and SN progenitor masses. We will search for light echoes around SNe, an important clue to their progenitor systems. We also propose to image several ''SN impostors'' - faint SNe IIn with massive progenitors - to verify whether they are indeed super-outbursts of luminous blue variables and survived the explosions, or a new/weak class of massive-star explosions.

  11. Seeking more Opportunities of Check Dams' harmony with nearby Circumstances via Design Thinking Process

    Science.gov (United States)

    Lin, Huan-Chun; Chen, Su-Chin; Tsai, Chen-Chen

    2014-05-01

    The contents of engineering design should indeed contain both science and art fields. However, the art aspect is too less discussed to cause an inharmonic impact with natural surroundings, and so are check dams. This study would like to seek more opportunities of check dams' harmony with nearby circumstances. According to literatures review of philosophy and cognition science fields, we suggest a thinking process of three phases to do check dams design work for reference. The first phase, conceptualization, is to list critical problems, such as the characteristics of erosion or deposition, and translate them into some goal situations. The second phase, transformation, is to use cognition methods such as analogy, association and metaphors to shape an image and prototypes. The third phase, formation, is to decide the details of the construction, such as stable safety analysis of shapes or materials. According to the previous descriptions, Taiwan's technological codes or papers about check dam design mostly emphasize the first and third phases, still quite a few lacks of the second phase. We emphases designers shouldn't ignore any phase of the framework especially the second one, or they may miss some chances to find more suitable solutions. Otherwise, this conceptual framework is simple to apply and we suppose it's a useful tool to design a more harmonic check dam with nearby natural landscape. Key Words: check dams, design thinking process, conceptualization, transformation, formation.

  12. IDENTIFYING NEARBY, YOUNG, LATE-TYPE STARS BY MEANS OF THEIR CIRCUMSTELLAR DISKS

    International Nuclear Information System (INIS)

    Schneider, Adam; Song, Inseok; Melis, Carl; Zuckerman, B.; Bessell, Mike

    2012-01-01

    It has recently been shown that a significant fraction of late-type members of nearby, very young associations (age ∼<10 Myr) display excess emission at mid-IR wavelengths indicative of dusty circumstellar disks. We demonstrate that the detection of mid-IR excess emission can be utilized to identify new nearby, young, late-type stars including two definite new members ('TWA 33' and 'TWA 34') of the TW Hydrae Association (TWA). Both new TWA members display mid-IR excess emission in the Wide-field Infrared Survey Explorer catalog and they show proper motion and youthful spectroscopic characteristics—namely, Hα emission, strong lithium absorption, and low surface gravity features consistent with known TWA members. We also detect mid-IR excess—the first unambiguous evidence of a dusty circumstellar disk—around a previously identified UV-bright, young, accreting star (2M1337) that is a likely member of the Lower-Centaurus Crux region of the Scorpius-Centaurus Complex.

  13. DARC servis konvencionalne FM radio-difuzije / DARC service conventional FM radio broadcasting

    Directory of Open Access Journals (Sweden)

    Mladen Manjak

    2006-07-01

    Full Text Available Konvencionalna FM radio-difuzija može ponuditi dodatne servise uz pomoć podnosioca smještenih u slobodnom dijelu osnovnog opsega multipleksiranog signala. U radu su prikazane osnovne karakteristike DARC servisa FM radio-difuzije i njegove moguće primjene. / Conventional FM radio broadcasting can offer additional services by means of a subcarrier placed in a clear part of the beseband multiplex signal. This paper contains elementary characteristics of DARC service conventional FM radio broadcasting and possible applications.

  14. Phenomenology of Neptune's radio emissions observed by the Voyager planetary radio astronomy experiment

    Science.gov (United States)

    Pedersen, B. M.; Lecacheux, A.; Zarka, P.; Aubier, M. G.; Kaiser, M. L.; Desch, M. D.

    1992-01-01

    The Neptune flyby in 1989 added a new planet to the known number of magnetized planets generating nonthermal radio emissions. We review the Neptunian radio emission morphology as observed by the planetary radio astronomy experiment on board Voyager 2 during a few weeks before and after closest approach. We present the characteristics of the two observed recurrent main components of the Neptunian kilometric radiation, i.e., the 'smooth' and the 'bursty' emissions, and we describe the many specific features of the radio spectrum during closest approach.

  15. The Cubesat Radio Experiment (CURE) and Beyond: Cubesat-based Low Frequency Radio Interferometry

    Science.gov (United States)

    Saint-Hilaire, P.; Sundkvist, D. J.; Martinez Oliveros, J. C.; Sample, J. G.; Pulupa, M.; Maruca, B.; Bale, S. D.; Bonnell, J. W.; Mozer, F.; Hurford, G. J.

    2014-12-01

    We have proposed a 3U cubesat, to carry a low-frequency radio receiver into low-Earth orbit to study solar radio bursts induced by solar flares and Coronal Mass Ejections. Because of the reflective properties of the Earth's ionosphere, observations of radio waves around and below 10 MHz must be made from space. The measurements will allow continuous tracking of radio bursts and associated CMEs through the inner heliosphere. These observations are important since such events are the main cause for space weather disturbances. Data products from the mission will primarily be spectra and waveforms of solar radio type II and III bursts, and the direction to the radio source as it propagates through the inner heliosphere. These data products will be available to the community through an automated pipeline nominally within a few hours of downlink. Additional science data products will be sizes of radio sources obtained via lunar occultations, and local ionospheric plasma density and electron temperature. As a first cubesat with a scientific radio instrument at these frequencies, this project is also intended as a path-finder: the instrument and sub-systems can immediately be duplicated in other cubesats, with the goal of providing the first radio interferometric measurements below the ionospheric cutoff.

  16. SIGNAL PROCESSING UTILIZING RADIO FREQUENCY PHOTONICS

    Science.gov (United States)

    2017-09-07

    AFRL-RY-WP-TR-2017-0172 SIGNAL PROCESSING UTILIZING RADIO FREQUENCY PHOTONICS Preetpaul S. Devgan RF/EO Subsystems Branch Aerospace Components...4. TITLE AND SUBTITLE SIGNAL PROCESSING UTILIZING RADIO FREQUENCY PHOTONICS 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT...can be used for multiple signal processing applications. Down conversion, oscillators analog to digital conversion and waveform generation are

  17. Big Data Challenges for Large Radio Arrays

    Science.gov (United States)

    Jones, Dayton L.; Wagstaff, Kiri; Thompson, David; D'Addario, Larry; Navarro, Robert; Mattmann, Chris; Majid, Walid; Lazio, Joseph; Preston, Robert; Rebbapragada, Umaa

    2012-01-01

    Future large radio astronomy arrays, particularly the Square Kilometre Array (SKA), will be able to generate data at rates far higher than can be analyzed or stored affordably with current practices. This is, by definition, a "big data" problem, and requires an end-to-end solution if future radio arrays are to reach their full scientific potential. Similar data processing, transport, storage, and management challenges face next-generation facilities in many other fields.

  18. Review of Radio Frequency Photonics Basics

    Science.gov (United States)

    2017-09-06

    AFRL-RY-WP-TR-2017-0157 REVIEW OF RADIO FREQUENCY PHOTONICS BASICS Preetpaul S. Devgan RF/EO Subsystems Branch Aerospace Components & Subsystems...Final March 1, 2007 – July 31, 2017 4. TITLE AND SUBTITLE REVIEW OF RADIO FREQUENCY PHOTONICS BASICS 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER...display or disclose the work. PAO case number 88ABW-2017-4067, Clearance Date 23 August 2017. Report contains color. 14. ABSTRACT Photonics can operate

  19. NASA's SDR Standard: Space Telecommunications Radio System

    Science.gov (United States)

    Reinhart, Richard C.; Johnson, Sandra K.

    2007-01-01

    A software defined radio (SDR) architecture used in space-based platforms proposes to standardize certain aspects of radio development such as interface definitions, functional control and execution, and application software and firmware development. NASA has charted a team to develop an open software defined radio hardware and software architecture to support NASA missions and determine the viability of an Agency-wide Standard. A draft concept of the proposed standard has been released and discussed among organizations in the SDR community. Appropriate leveraging of the JTRS SCA, OMG s SWRadio Architecture and other aspects are considered. A standard radio architecture offers potential value by employing common waveform software instantiation, operation, testing and software maintenance. While software defined radios offer greater flexibility, they also poses challenges to the radio development for the space environment in terms of size, mass and power consumption and available technology. An SDR architecture for space must recognize and address the constraints of space flight hardware, and systems along with flight heritage and culture. NASA is actively participating in the development of technology and standards related to software defined radios. As NASA considers a standard radio architecture for space communications, input and coordination from government agencies, the industry, academia, and standards bodies is key to a successful architecture. The unique aspects of space require thorough investigation of relevant terrestrial technologies properly adapted to space. The talk will describe NASA s current effort to investigate SDR applications to space missions and a brief overview of a candidate architecture under consideration for space based platforms.

  20. Paradigms of modern radio-biology

    International Nuclear Information System (INIS)

    Grodzins'kij, D.M.

    2005-01-01

    The basic paradigms of modern radio-biology are considered as models of pictures of essence of radio-biology problems and methods of their decision. It is marked on absolute heuristics of these ascending conceptual assertions and their assistance to subsequent development of experimental science. That has the concrete display in the decision of actual tasks of protection of people from action of ionizing radiation

  1. Survey of Potential Radio Frequency Interference Sources.

    Science.gov (United States)

    1980-05-13

    Article 5 of the International Telecomunications Union (ITU) Radio Regulations, 1968 Edition, as revised by the World Administrative Radio Conferences (WARC...392AA In Brazil , Canada and the United States of America, the band 6 625-7 125 MHz is also allocated on a secondary basis to the fixed-satellite...Republic (34) Arab Jamnahiriya) (4) Brazil (Federative Republic of) (29) Liechtenstein (Principality of) (28) (--3) Canada (19) Luxembourg (32) Chile

  2. Voyager-Jupiter radio science data papers

    Science.gov (United States)

    Levy, G. S.; Wood, G. E.

    1980-01-01

    The reduction and interpretation of the radio science data from the Voyager 1 and 2 encounters of the planet Jupiter and its satellites resulted in the preparation of several papers for publication in the special Voyager-Jupiter issue of the Journal of Geophysical Research. The radio science and tracking systems of the Deep Space Network provide the data which makes this research possible. This article lists submitted papers by title, with their authors and with abstracts of their contents.

  3. Expanded radio art as PhD practice

    OpenAIRE

    Hall, M.

    2015-01-01

    Radio After Radio: Redefining Radio Art in the Light of New Media Technology through Expanded Practice is the title of my PhD practice based research. This paper focuses on the extended boundaries of radio art, considering how radio art might be defined in relation to sound art, music, and media art. Mapping the shifting parameters of radio art in the digital era has prompted a consideration of how radio can be seen to be moving from being a predominantly shared "live" event to one consumed "...

  4. Radio-flaring Ultracool Dwarf Population Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Route, Matthew, E-mail: mroute@purdue.edu [Department of Astronomy and Astrophysics, the Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

    2017-08-10

    Over a dozen ultracool dwarfs (UCDs), low-mass objects of spectral types ≥M7, are known to be sources of radio flares. These typically several-minutes-long radio bursts can be up to 100% circularly polarized and have high brightness temperatures, consistent with coherent emission via the electron cyclotron maser operating in approximately kilogauss magnetic fields. Recently, the statistical properties of the bulk physical parameters that describe these UCDs have become described adequately enough to permit synthesis of the population of radio-flaring objects. For the first time, I construct a Monte Carlo simulator to model the population of these radio-flaring UCDs. This simulator is powered by Intel Secure Key (ISK), a new processor technology that uses a local entropy source to improve random number generation that has heretofore been used to improve cryptography. The results from this simulator indicate that only ∼5% of radio-flaring UCDs within the local interstellar neighborhood (<25 pc away) have been discovered. I discuss a number of scenarios that may explain this radio-flaring fraction and suggest that the observed behavior is likely a result of several factors. The performance of ISK as compared to other pseudorandom number generators is also evaluated, and its potential utility for other astrophysical codes is briefly described.

  5. Radio astronomy and spectrum management - The impact of WARC-79

    International Nuclear Information System (INIS)

    Pankonin, V.; Price, R.M.

    1981-01-01

    The characteristics of radio astronomy are considered, taking into account broad-band and narrow-band cosmic radiation, the evolution of equipment and techniques of the radio astronomer toward better sensitivity and better angular resolution, and the three general classes into which radio telescopes can be divided. Attention is given to the extraordinary interference problems faced by radio astronomers, the location of radio-astronomy observatories in secluded locations, the preparation by radio astronomers and space scientists for WARC-79, the actions taken at WARC-79, and the WARC impact. It is pointed out that radio astronomy has emerged from WARC-79 in a better position in the International Radio Regulations than it has ever enjoyed in the past. Radio astronomers can be satisfied that the requirements of their radio service are generally being given serious consideration. Most of the requests for allocations have been granted at frequencies above 20 GHz

  6. Plasma Diagnostics of the Interstellar Medium with Radio Astronomy

    OpenAIRE

    Haverkorn, Marijke; Spangler, Steven R.

    2013-01-01

    We discuss the degree to which radio propagation measurements diagnose conditions in the ionized gas of the interstellar medium (ISM). The "signal generators" of the radio waves of interest are extragalactic radio sources (quasars and radio galaxies), as well as Galactic sources, primarily pulsars. The polarized synchrotron radiation of the Galactic non-thermal radiation also serves to probe the ISM, including space between the emitting regions and the solar system. Radio propagation measurem...

  7. Synthesis of radio-metallofullerenols

    International Nuclear Information System (INIS)

    Keisuke Sueki; Yu Iwai

    2005-01-01

    Water-soluble fullerene derivatives have been investigated to date mostly within the framework of biological and medical applications. For example, C 60 derivatives have been applied as HIV inhibitors, radical scavenging capabilities and anti-cancer. The C 60 fullerenols, C 60 (OH) n , have been synthesized and have shown excellent water solubility. Kitazawa and co-workers also reported a more efficient reaction to obtain C 60 (OH) n , using NaOH aq and tetrabutylammonium hydroxide as a phase transfer catalyst. Water-soluble endohedral metallofullerene derivatives are particularly interesting because of their possible applications to radiotracers and magnetic resonance imaging (MRI) contrast agents. We investigate to trace the synthesis process of metallofullalnols using radioactivity, and obtain the effective process of radio-metallofullerenols. Carbon soot containing Sm endohedoral metallofullerenes was produced by the dc arc discharge method. The resulting soot was extracted with o-dichlorobenzene by reflux for 5 h. The obtained crude was irradiated for 30 min in the JRR4, After irradiation, crude was dissolved by toluene and filtrated by 0.2 μm pore size filter. The separation of the Sm doped C 82 including 153 Sm tracer from the crude was achieved by HPLC method which is a HPLC process on the Buckyprep column. We obtained fraction containing of three kinds of Sm doped C 82 . Details of the syntheses of endohedral metallofullerenols have been reported elsewhere. Briefly, toluene solutions of isolated Sm doped C 82 including 153 Sm with C 60 were vigorously vibrated with saturation KOH aq containing few drops of TBAH (10 % in water) as catalyst at room temperature. The reaction times were changed from l minute to 8 hours. The reaction mixture was filtrated by 0.2 μm filter. The residue was rinsed with methanol to ensure the removal of the catalyst and KOH. The rinsed residue was dissolved in water for 7 hours. The resultant brown- solution was the passed down

  8. How many radio relics await discovery?

    Science.gov (United States)

    Nuza, S. E.; Hoeft, M.; van Weeren, R. J.; Gottlöber, S.; Yepes, G.

    2012-03-01

    Upcoming radio telescopes will allow us to study the radio sky at low frequencies with unprecedented sensitivity and resolution. New surveys are expected to discover a large number of new radio sources, in particular those with a steep radio spectrum. Here we investigate the abundance of radio relics, i.e. steep-spectrum diffuse radio emission coming from the periphery of galaxy clusters, which is believed to trace shock waves induced by cluster mergers. With the advent of comprehensive relic samples, a framework is needed to analyse the relic abundance statistically. To this end, we introduce the probability of finding a relic located in a galaxy cluster with given mass and redshift, which allows us to relate the halo mass function of the Universe to radio-relic number counts. To date, about 45 relics have been reported in the literature and we compile the resulting counts, N(>S1.4). In principle, the parameters of the distribution could be determined using a sufficiently large relic sample. However, since the number of known relics is still small, for that purpose we use the MARENOSTRUM UNIVERSE simulation to determine the relic radio-power scaling with cluster mass and redshift. Our model is able to reproduce the recently found tentative evidence for an increase in the fraction of clusters hosting relics, both with X-ray luminosity and redshift, using an X-ray flux-limited cluster sample. Moreover, we find that a considerable fraction of faint relics (S1.4≲ 10 mJy) reside in clusters with an X-ray flux below ≲ 3 × 10-12 erg s-1 cm-2. Finally, we estimate the number of radio relics that await discovery by future low-frequency surveys proposed for the Low Frequency Array (LOFAR) and the Westerbork Synthesis Radio Telescope (WSRT). We estimate that the Westerbork Observations of the Deep APERTIF Northern-Sky (WODAN) survey proposed for WSRT may discover 900 relics and that the LOFAR-Tier 1-120 MHz survey may discover about 2500 relics. However, the actual

  9. Direct and nearby lightning strike interaction with test power distribution lines

    Science.gov (United States)

    Schoene, Jens Daniel

    The interaction of direct and nearby rocket-triggered lightning with two unenergized three-phase power distribution lines of about 800 m length was studied at the International Center for Lightning Research and Testing in Florida. A horizontally-configured line was tested in 1999 and 2000, a vertically-configured line in 2001, 2002, and 2003, and a vertically-configured line with overhead ground wire in 2004. All lines were equipped with arresters and, additionally, in 2003, the vertical line had a polemounted transformer. During the 2000, 2001, and 2002 direct strike experiments, arresters frequently failed, but there was no arrester failures either during the 2003 direct strike experiment when the transformer was on the line or during the 2004 direct strike experiment when the lightning current was injected into the overhead ground wire. All line configurations except the one tested in 2004 commonly exhibited flashovers. The division of return stroke currents for the vertically-configured line was initially similar to the division on the horizontally-configured line (that is, the arresters closest to the strike point conducted the bulk of the impulsive current). After some tens of microseconds the currents in all arresters on the vertically-configured line equalized, while the close arrester currents on the horizontally-configured line still conducted significantly more current than the remote arresters. The lightning current division for direct strikes to a phase conductor is successfully modeled with the Electromagnetic Transient Program (EMTP) for the vertically-configured line and, if the residual voltage of the close arresters is reduced by 20%, successfully modeled for the horizontally-configured line. Currents on the vertically-configured line induced by nearby lightning strikes were measured and compared to results calculated using the LIOV-EMTP96 code. It was found that during a lightning strike 11 m from a grounded line pole, a significant fraction of

  10. Astronomers Detect Powerful Bursting Radio Source Discovery Points to New Class of Astronomical Objects

    Science.gov (United States)

    2005-03-01

    transients has been very exciting for our students,” Hyman added. Participating in this research program has inspired at least two of Hyman?s students — Jennifer Neureuther and Mariana Lazarova — to pursue graduate studies in astronomy. This project was supported at Sweet Briar College by funding from Research Corporation and the Jeffress Foundation. Basic research in radio astronomy at NRL is supported by the Office of Naval Research. Further Research Hyman and his NRL colleagues plan to continue monitoring the Galactic center and search for the source again with the VLA and other X-ray and radio telescopes. They are also developing (with Dr. Kent Wood of NRL) a model that attempts to account for the radio bursts as a new type of outburst from a class of sources known as “magnetars.” NRL is also contributing to an effort to build the world’s largest and most sensitive low-frequency telescope, called the Long Wavelength Array (LWA), which may revolutionize future searches for other radio transient sources. Current plans call for the LWA, which is being developed by the University of New Mexico-led Southwest Consortium, to be sited in New Mexico, not far from the VLA. “One of the key advantages of observing at long radio wavelengths,” explained NRL astronomer, Dr. Namir Kassim, “is that the field-of-view is so large that a single observation can efficiently detect transient phenomena over a large region.” “When completed, the LWA may uncover hundreds of previously unknown radio transients, some of which may be examples of Jupiter-like planets orbiting other stars,” Kassim added. Jupiter is the most famous example of a nearby radio transient. About Sweet Briar College Sweet Briar College is consistently ranked among the nation’s top liberal arts colleges.ÿ Founded in 1901 as an independent undergraduate college for women, Sweet Briar continues its commitment to the education of women, offering a full range of liberal arts majors, including subjects

  11. Curved Radio Spectra of Weak Cluster Shocks

    Science.gov (United States)

    Kang, Hyesung; Ryu, Dongsu

    2015-08-01

    In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.

  12. VLA radio observations of AR Scorpii

    Science.gov (United States)

    Stanway, E. R.; Marsh, T. R.; Chote, P.; Gänsicke, B. T.; Steeghs, D.; Wheatley, P. J.

    2018-03-01

    Aims: AR Scorpii is unique amongst known white dwarf binaries in showing powerful pulsations extending to radio frequencies. Here we aim to investigate the multi-frequency radio emission of AR Sco in detail, in order to constrain its origin and emission mechanisms. Methods: We present interferometric radio frequency imaging of AR Sco at 1.5, 5 and 9 GHz, analysing the total flux and polarization behaviour of this source at high time resolution (10, 3 and 3 s), across a full 3.6 h orbital period in each band. Results: We find strong modulation of the radio flux on the orbital period and the orbital sideband of the white dwarf's spin period (also known as the "beat" period). This indicates that, like the optical flux, the radio flux arises predominantly from on or near the inner surface of the M-dwarf companion star. The beat-phase pulsations of AR Sco decrease in strength with decreasing frequency. They are strongest at 9 GHz and at an orbital phase 0.5. Unlike the optical emission from this source, radio emission from AR Sco shows weak linear polarization but very strong circular polarization, reaching 30% at an orbital phase 0.8. We infer the probable existence of a non-relativistic cyclotron emission component, which dominates at low radio frequencies. Given the required magnetic fields, this also likely arises from on or near the M-dwarf. A table of the flux time series is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A66

  13. Transistor Radio Receivers; Radio and Television Service, Intermediate: 9785.04.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    The course outlined is one of the required courses in the Radio and Television Service Curriculum. Mastery of the skills in Basic Radio Circuits and Vacuum Tube AM Troubleshooting (9785.03) is a prerequisite. Eight blocks of instruction are divided into several units each. The instruction blocks are: orientation, fundamentals of transistor…

  14. Perancangan Radio Streaming Edukasi (Studi Kasus Balai Pengembangan Media Radio YOGYAKARTA)

    OpenAIRE

    Nurwulan, Ayu Isni; Paputungan, Irving Vitra

    2009-01-01

    Pendidikan berkualitas sudah sewajarnya bisa dinikmati secara merata oleh semua orang. Mediapembelajaran secara audio yang selama ini disampaikan masih memiliki banyak keterbatasan, terutama padalingkup wilayah penyampaian. Dalam makalah ini, sebuah media pendidikan berbasis audio dengan cara laindiusulkan. Media tersebut bernama radio streaming. Pembuatan radio streaming memerlukan banyak analisissehingga perancangannya tepat. Hasil analisis dan perancangan yang disampaikan dalam makalah ini...

  15. HIGH-RESOLUTION RADIO OBSERVATIONS OF INTERMEDIATE REDSHIFT QUASARS AND RADIO GALAXIES

    NARCIS (Netherlands)

    BOGERS, WJ; HES, R; BARTHEL, PD; ZENSUS, JA

    We present radio maps of a collection of intermediate redshift quasars and radio galaxies mostly taken from the 3C and 4C catalogues. The sources were observed with the Very Large Array (VLA) at one or more of the following frequencies: 15 GHz, 8.4 GHz or 1.4 GHz. Several basic source parameters axe

  16. Observations of compact radio nuclei in Cygnus A, Centaurus A, and other extended radio sources

    International Nuclear Information System (INIS)

    Kellermann, K.I.; Clark, B.G.; Niell, A.E.; Shaffer, D.B.

    1975-01-01

    Observations of Cygnus A show a compact radio core 2 milli-arcsec in extent oriented in the same direction as the extended components. Other large double- or multiple-component sources, including Centaurus A, have also been found to contain compact radio nuclei with angular sizes in the range 1--10 milli-arcsec

  17. La radio en África. Una radio para el desarrollo

    Directory of Open Access Journals (Sweden)

    Jean-Paul Lafrance

    2015-01-01

    Full Text Available La radio de tipo comunitario, tal como la conocemos en Norteamérica y Europa (no-comercial, no-estatal y particípatíva, no existe en Africa. Sin embargo, la situación histórica y el contexto socio-político particulares de Africa han precedido la instauración de una radio que, dentro del marco del presente estudio, nos ha resultado interesante. Se trata de la radio educativa rural. Aunque enmarcada dentro del molde estatal de regímenes que en su mayoría son dictaduras, la radio rural africana, al igual que las radios de tipo comunitario, utiliza la radio con otros fines además de los convencionales. En este caso, la radio es un instrumento al servicio del desarrollo, por no decir al servicio del campesino, en una relación con éste último que probablemente dejará cada vez más de ser uni-direccional. La experiencia africana nos proporcionará en esta perspectiva nuevos elementos de reflexión en lo que respecta al rol de la radio dentro de la comunidad y sobre las condiciones incluso del éxito o no-éxito de la participación popular.

  18. Stellar Photometric Structures of the Host Galaxies of Nearby Type 1 Active Galactic Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Minjin [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Peng, Chien Y. [Giant Magellan Telescope Corporation, 251 S. Lake Ave., Suite 300, Pasadena, CA 91101 (United States); Barth, Aaron J. [Department of Physics and Astronomy, University of California at Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697-4575 (United States); Im, Myungshin, E-mail: mkim@kasi.re.kr, E-mail: lho.pku@gmail.com, E-mail: peng@gmto.org, E-mail: barth@uci.edu, E-mail: mim@astro.snu.ac.kr [Department of Physics and Astronomy, Frontier Physics Research Division (FPRD), Seoul National University, Seoul (Korea, Republic of)

    2017-10-01

    We present detailed image analysis of rest-frame optical images of 235 low-redshift ( z ≲ 0.35) Type 1 active galactic nuclei (AGNs) observed with the Hubble Space Telescope . The high-resolution images enable us to perform rigorous two-dimensional image modeling to decouple the luminous central point source from the host galaxy, which, when warranted, is further decomposed into its principal structural components (bulge, bar, and disk). In many cases, care must be taken to account for structural complexities such as spiral arms, tidal features, and overlapping or interacting companion galaxies. We employ Fourier modes to characterize the degree of asymmetry of the light distribution of the stars as a quantitative measure of morphological distortion due to interactions or mergers. We examine the dependence of the physical parameters of the host galaxies on the properties of the AGNs, namely, radio-loudness and the width of the broad emission lines. In accordance with previous studies, narrow-line (H β FWHM ≤ 2000 km s{sup −1}) Type 1 AGNs, in contrast to their broad-line (H β FWHM > 2000 km s{sup −1}) counterparts, are preferentially hosted in later-type, lower-luminosity galaxies, which have a higher incidence of pseudo-bulges, are more frequently barred, and are less morphologically disturbed. This suggests that narrow-line Type 1 AGNs experienced a more quiescent evolutionary history driven primarily by internal secular evolution instead of external dynamical perturbations. The fraction of AGN hosts showing merger signatures is larger for more luminous sources. Radio-loud AGNs generally preferentially live in earlier-type (bulge-dominated), more massive hosts, although a minority of them appear to contain a significant disk component. We do not find convincing evidence for enhanced merger signatures in the radio-loud population.

  19. Relativistic deflection of background starlight measures the mass of a nearby white dwarf star.

    Science.gov (United States)

    Sahu, Kailash C; Anderson, Jay; Casertano, Stefano; Bond, Howard E; Bergeron, Pierre; Nelan, Edmund P; Pueyo, Laurent; Brown, Thomas M; Bellini, Andrea; Levay, Zoltan G; Sokol, Joshua; Dominik, Martin; Calamida, Annalisa; Kains, Noé; Livio, Mario

    2017-06-09

    Gravitational deflection of starlight around the Sun during the 1919 total solar eclipse provided measurements that confirmed Einstein's general theory of relativity. We have used the Hubble Space Telescope to measure the analogous process of astrometric microlensing caused by a nearby star, the white dwarf Stein 2051 B. As Stein 2051 B passed closely in front of a background star, the background star's position was deflected. Measurement of this deflection at multiple epochs allowed us to determine the mass of Stein 2051 B-the sixth-nearest white dwarf to the Sun-as 0.675 ± 0.051 solar masses. This mass determination provides confirmation of the physics of degenerate matter and lends support to white dwarf evolutionary theory. Copyright © 2017, American Association for the Advancement of Science.

  20. IceCube search for dark matter annihilation in nearby galaxies and galaxy clusters

    Science.gov (United States)

    Aartsen, M. G.; Abbasi, R.; Abdou, Y.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Bechet, S.; Becker Tjus, J.; Becker, K.-H.; Benabderrahmane, M. L.; BenZvi, S.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Bertrand, D.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohaichuk, S.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Bretz, H.-P.; Brown, A. M.; Bruijn, R.; Brunner, J.; Carson, M.; Casey, J.; Casier, M.; Chirkin, D.; Christov, A.; Christy, B.; Clark, K.; Clevermann, F.; Coenders, S.; Cohen, S.; Cowen, D. F.; Cruz Silva, A. H.; Danninger, M.; Daughhetee, J.; Davis, J. C.; Day, M.; De Clercq, C.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; Dunkman, M.; Eagan, R.; Eberhardt, B.; Eisch, J.; Ellsworth, R. W.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Franckowiak, A.; Frantzen, K.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Goodman, J. A.; Góra, D.; Grandmont, D. T.; Grant, D.; Groß, A.; Ha, C.; Haj Ismail, A.; Hallen, P.; Hallgren, A.; Halzen, F.; Hanson, K.; Heereman, D.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Jagielski, K.; Japaridze, G. S.; Jero, K.; Jlelati, O.; Kaminsky, B.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kiryluk, J.; Kläs, J.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krasberg, M.; Krings, K.; Kroll, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Landsman, H.; Larson, M. J.; Lesiak-Bzdak, M.; Leuermann, M.; Leute, J.; Lünemann, J.; Macías, O.; Madsen, J.; Maggi, G.; Maruyama, R.; Mase, K.; Matis, H. S.; McNally, F.; Meagher, K.; Merck, M.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke, A.; Odrowski, S.; Olivas, A.; Omairat, A.; O'Murchadha, A.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rädel, L.; Rameez, M.; Rawlins, K.; Redl, P.; Reimann, R.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Riedel, B.; Rodrigues, J. P.; Rott, C.; Ruhe, T.; Ruzybayev, B.; Ryckbosch, D.; Saba, S. M.; Salameh, T.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Scheriau, F.; Schmidt, T.; Schmitz, M.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schulz, O.; Seckel, D.; Sestayo, Y.; Seunarine, S.; Shanidze, R.; Sheremata, C.; Smith, M. W. E.; Soldin, D.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stasik, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Tepe, A.; Ter-Antonyan, S.; Tešić, G.; Tilav, S.; Toale, P. A.; Toscano, S.; Unger, E.; Usner, M.; Vallecorsa, S.; van Eijndhoven, N.; Van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Weaver, Ch.; Wellons, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Ziemann, J.; Zierke, S.; Zoll, M.

    2013-12-01

    We present the results of a first search for self-annihilating dark matter in nearby galaxies and galaxy clusters using a sample of high-energy neutrinos acquired in 339.8 days of live time during 2009/10 with the IceCube neutrino observatory in its 59-string configuration. The targets of interest include the Virgo and Coma galaxy clusters, the Andromeda galaxy, and several dwarf galaxies. We obtain upper limits on the cross section as a function of the weakly interacting massive particle mass between 300 GeV and 100 TeV for the annihilation into bb¯, W+W-, τ+τ-, μ+μ-, and νν¯. A limit derived for the Virgo cluster, when assuming a large effect from subhalos, challenges the weakly interacting massive particle interpretation of a recently observed GeV positron excess in cosmic rays.