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15 results on '"Lovell JEJ"'

1. Interstellar scintillation and scattering of micro-arc-second AGN

Author

Jauncey, DL, Bignall, HE, Kedziora-Chudczer, L, Koay, JY, Lovell, JEJ, Macquart, JP, Ojha, R, Pursimo, T, Reynolds, C, Rickett, BJ, Jauncey, DL, Bignall, HE, Kedziora-Chudczer, L, Koay, JY, Lovell, JEJ, Macquart, JP, Ojha, R, Pursimo, T, Reynolds, C, and Rickett, BJ

Abstract

The discovery of the first quasar 3C 273 led directly to the discovery of their variability at optical and radio wavelengths. We review the radio variability observations, in particular the variability found at frequencies below 1 GHz, as well as those exhibiting intra-day variability (IDV) at cm wavelengths. Observations have shown that IDV arises principally from scintillation caused by scattering in the ionized interstellar medium of our Galaxy. The sensitivity of interstellar scintillation towards source angular sizes has provided a powerful tool for studying the most compact components of radio-loud AGN at microarcsecond and milliarcsecond scale resolution.

Published
2016

2. Interstellar scintillation and annual cycles in the BL Lac source PKS 1519-273

Author

Jauncey, DL, Johnston, HM, Bignall, HE, Lovell, JEJ, Kedziora-Chudczer, L, Tzioumis, AK, Macquart, JP, and Kapteyn Astronomical Institute

Subjects
RADIO-SOURCES, INTRADAY VARIABILITY, QUASAR J1819+3845, SPECTRA, OBJECTS
Abstract

We have measured annual cycles in the time scales of the rapid, intra-day variability of the total and circularly polarized flux density, of the unusual BL Lac source PKS 1519- 273 at 4.8 and 8.6 GHz. The data were collected at the ATCA over the last seven years, and establish unequivocally interstellar scintillation as the principal mechanism responsible for this cm-wavelength intra-day variability.

Published
2003

4. MASIV: The Microarcsecond Scintillation-Induced Variability Survey

Author

Lovell, JEJ, Dutka, M, Kedziora-Chudczer, L, Jauncey, DL, Senkbeil, CE, Shabala, S, Bignall, HE, Pursimo, T, Ojha, R, Macquart, JP, Rickett, BJ, Lovell, JEJ, Dutka, M, Kedziora-Chudczer, L, Jauncey, DL, Senkbeil, CE, Shabala, S, Bignall, HE, Pursimo, T, Ojha, R, Macquart, JP, and Rickett, BJ

5. The VSOP Survey: final aggregate results

Author

Dodson, R, Murata, Y, Moellenbrock, G, Gurvits, L, Shen, Z, Lovell, JEJ, Horiuchi, S, Scott, W, Fomalont, E, Paragi, Z, Frey, S, Wiik, K, Hirabayashi, H, Edwards, PG, Dodson, R, Murata, Y, Moellenbrock, G, Gurvits, L, Shen, Z, Lovell, JEJ, Horiuchi, S, Scott, W, Fomalont, E, Paragi, Z, Frey, S, Wiik, K, Hirabayashi, H, and Edwards, PG

6. Microarcsecond scintillation-induced variability (MASIV) survey of the northern sky

Author

Jauncey, DL, Rickett, BJ, Kedziora-Chudczer, L, Lovell, JEJ, Senkbeil, CE, Shabala, S, Bignall, HE, Pursimo, T, Ojha, R, Dutka, M, Macquart, JP, Jauncey, DL, Rickett, BJ, Kedziora-Chudczer, L, Lovell, JEJ, Senkbeil, CE, Shabala, S, Bignall, HE, Pursimo, T, Ojha, R, Dutka, M, and Macquart, JP

Abstract

We present the results of a large-scale 5-GHz Very Large Array (VLA) survey of the northern sky searching for sources that exhibit intraday variability (IDV). The observations were made over four epochs, each of 3 days in January, May and September 2002 and January 2003. The objective is to obtain a large sample of IDV sources in order to derive reliable statistics of the microarcsecond properties of the source population and the scattering properties of the interstellar mediu

7. H2O maser emission from bright rimmed clouds in the southern hemisphere

Author

Valdettaro, R, Chapman, JM, Lovell, JEJ, Palla, F, Valdettaro, R, Chapman, JM, Lovell, JEJ, and Palla, F

Abstract

Water maser emission is a powerful tracer of the presence of embedded sources in dense clouds since it requires elevated temperatures (>100 K) and densities (>107 cm−3) that can be found in circumstellar disks and/or jets/outflows associated with Young Stellar Objects. Bright rimmed clouds compressed by ionization fronts from nearby massive stars are considered good examples of externally triggered star formation, possibly resulting in the formation of massive stars. Aims. We aim to determine the water maser emission frequency and characteristics of 45 bright rimmed clouds in the southern hemisphere identified by Sugitani & Ogura (1994, ApJS, 92, 163). Methods. We have used the Tidbinbilla 70-m radiotelescope to perform a high sensitivity survey at 22.2 GHz of the maser emission from the 616−523 rotational transition of H2O molecules. Results. We found 7 water maser sources out of 44 (16% detection rate), 5 being new detections. With the exception of the maser associated with BRC 68, all the other maser are characterized by low integrated fluxes and luminosities. Conclusions. Most maser sources fall below the correlation between the H2O and far-infrared luminosity found in other studies towards a variety of star forming regions. These results are similar to those found in the companion survey of BRCs in the northern hemisphere by Valdettaro et al. (2005, A&A, 443, 535). The low detection frequency and the properties of water maser emission from BRCs indicate that low-mass star formation is the most natural outcome of the external compression induced by the ionization front from nearby massive stars.

9. The VSOP Survey: final aggregate results

Author

Dodson, R, Murata, Y, Moellenbrock, G, Gurvits, L, Shen, Z, Lovell, JEJ, Horiuchi, S, Scott, W, Fomalont, E, Paragi, Z, Frey, S, Wiik, K, Hirabayashi, H, Edwards, PG, Dodson, R, Murata, Y, Moellenbrock, G, Gurvits, L, Shen, Z, Lovell, JEJ, Horiuchi, S, Scott, W, Fomalont, E, Paragi, Z, Frey, S, Wiik, K, Hirabayashi, H, and Edwards, PG

10. Science with the Australian square kilometre array pathfinder

Author

Johnston, S, Darling, J, Deller, A, Dodson, R, Edwards, PG, Ekers, R, Ellingsen, SP, Feain, I, Gaensler, BM, Haverkorn, M, Hobbs, G, Bailes, M, Hopkins, A, Jackson, C, James, C, Joncas, G, Kaspi, V, Kilborn, V, Koribalski, B, Kothes, R, Landecker, TL, Lenc, E, Bartel, N, Lovell, JEJ, Macquart, JP, Manchester, RN, Matthews, D, McClure-Griffiths, NM, Norris, Ray, Pen, UL, Phillips, CJ, Power, C, Protheroe, R, Baugh, C, Sadler, E, Schmidt, B, Stairs, I, Staveley-Smith, L, Stil, JM, Taylor, Russell, Tingay, S, Tzioumis, AK, Walker, Mark A, Wall, J, Bietenholz, M, Wolleben, M, Blake, C, Braun, R, Brown, JC, Chatterjee, S, Johnston, S, Darling, J, Deller, A, Dodson, R, Edwards, PG, Ekers, R, Ellingsen, SP, Feain, I, Gaensler, BM, Haverkorn, M, Hobbs, G, Bailes, M, Hopkins, A, Jackson, C, James, C, Joncas, G, Kaspi, V, Kilborn, V, Koribalski, B, Kothes, R, Landecker, TL, Lenc, E, Bartel, N, Lovell, JEJ, Macquart, JP, Manchester, RN, Matthews, D, McClure-Griffiths, NM, Norris, Ray, Pen, UL, Phillips, CJ, Power, C, Protheroe, R, Baugh, C, Sadler, E, Schmidt, B, Stairs, I, Staveley-Smith, L, Stil, JM, Taylor, Russell, Tingay, S, Tzioumis, AK, Walker, Mark A, Wall, J, Bietenholz, M, Wolleben, M, Blake, C, Braun, R, Brown, JC, and Chatterjee, S

Abstract

The future of centimetre and metre-wave astronomy lies with the Square Kilometre Array (SKA), a telescope under development by a consortium of 17 countries that will be 50 times more sensitive than any existing radio facility. Most of the key science for the SKA will be addressed through large-area imaging of the Universe at frequencies from a few hundred MHz to a few GHz. The Australian SKA Pathfinder (ASKAP) is a technology demonstrator aimed in the mid-frequency range, and achieves instantaneous wide-area imaging through the development and deployment of phased-array feed systems on parabolic reflectors. The large field-of- view makes ASKAP an unprecedented synoptic telescope that will make substantial advances in SKA key science. ASKAP will be located at the Murchison Radio Observatory in inland Western Australia, one of the most radio-quiet locations on the Earth and one of two sites selected by the international community as a potential location for the SKA. In this paper, we outline an ambitious science program for ASKAP, examining key science such as understanding the evolution, formation and population of galaxies including our own, understanding the magnetic Universe, revealing the transient radio sky and searching for gravitational waves.

11. MASIV: The Microarcsecond Scintillation-Induced Variability Survey

Author

Lovell, JEJ, Dutka, M, Kedziora-Chudczer, L, Jauncey, DL, Senkbeil, CE, Shabala, S, Bignall, HE, Pursimo, T, Ojha, R, Macquart, JP, Rickett, BJ, Lovell, JEJ, Dutka, M, Kedziora-Chudczer, L, Jauncey, DL, Senkbeil, CE, Shabala, S, Bignall, HE, Pursimo, T, Ojha, R, Macquart, JP, and Rickett, BJ

12. ANTARES constrains a blazar origin of two IceCube PeV neutrino events

Author

Adrián Martínez, S., Albert, A., André, M., Anton, G., Ardid, M., Aubert, J. J., Baret, B., Barrios, J., Basa, S., Bertin, V., Biagi, S., Bogazzi, C., Bormuth, R., Bou Cabo, M., Bouwhuis, M. C., Bruijn, R., Brunner, J., Busto, J., Capone, Antonio, Caramete, L., Carr, J., Chiarusi, T., Circella, M., Coniglione, R., Core, L., Costantini, H., Coyle, P., Creusot, A., De Rosa, G., Dekeyser, I., Deschamps, A., DE BONIS, Giulia, Distefano, C., Donzaud, C., Dornic, D., Dorosti, Q., Drouhin, D., Dumas, A., Eberl, T., Enzenhöfer, A., Escoffier, S., Fehn, K., Felis, I., Fermani, Paolo, Folger, F., Fusco, L. A., Galatà, S., Gay, P., Geißelsöder, S., Geyer, K., Giordano, V., Gleixner, A., Gřómez González, J. P., Graf, K., Guillard, G., van Haren, H., Heijboer, A. J., Hello, Y., Hernández Rey, J. J., Herold, B., Herrero, A., Hößl, J., Hofestädt, J., Hugon, C., James, C. W., de Jong, M., Kalekin, O., Katz, U., Kießling, D., Kooijman, P., Kouchner, A., Kulikovskiy, V., Lahmann, R., Lambard, E., Lambard, G., Lefèvre, D., Leonora, E., Loehner, H., Loucatos, S., Mangano, S., Marcelin, M., Margiotta, A., Martínez Mora, J. A., Martini, S., Mathieu, A., Michael, T., Migliozzi, P., Neff, M., Nezri, E., Palioselitis, D., Păvăląs, G. E., Pellegrino, C., Perrina, Chiara, Piattelli, P., Popa, V., Pradier, T., Racca, C., Riccobene, G., Richter, R., Roensch, K., Rostovtsev, A., Saldaña, M., Samtleben, D. F. E., Sánchez Losa, . A., Sanguineti, M., Sapienza, P., Schmid, J., Schnabel, J., Schulte, S., Schüssler, F., Seitz, T., Sieger, C., Spies, A., Spurio, M., Steijger, J. J. M., Stolarczyk, T. h., Taiuti, M., Tamburini, C., Tayalati, Y., Trovato, A., Vallage, B., Vallée, C., Van Elewyck, V., Visser, E., Vivolo, D., Wagner, S., de Wolf, E., Yatkin, K., Yepes, H., Zornoza, J. D., Zúñiga, J., Krauß, F., Kadler, M., Mannheim, . K., Schulz, R., Trüstedt, J., Wilms, J., Ojha, R., Ros, E., Baumgartner, W., Beuchert, T., Blanchard, J., Bürkel, C., Carpenter, B., Edwards, P. G., Eisenacher Glawion, D., Elsässer, D., Fritsch, U., Gehrels, N., Gräfe, C., Großberger, C., Hase, H., Horiuchi, S., Kappes, A., Kreikenbohm, A., Kreykenbohm, I., Langejahn, M., Leiter, K., Litzinger, E., Lovell, J. E. J., Müller, C., Phillips, C., Plötz, C., Quick, J., Steinbring, T., Stevens, J., Thompson, D. J., Tzioumis, A. K., Research unit Nuclear & Hadron Physics, Institut d’Investigació per a la Gestió Integrada de Zones Costaneres (IGIC), Universitat Politècnica de València (UPV), Groupe de Recherche en Physique des Hautes Energies (GRPHE), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut Universitaire de Technologie de Colmar, Laboratory of Applied Bioacoustics (LAB-UPC), Universidad Polytecnica de Cataluña (UPC), Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Centre de Physique des Particules de Marseille (CPPM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Aix Marseille Université (AMU), AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université Paris-Sud - Paris 11 (UP11), Département de Physique des Particules (ex SPP) (DPP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), The ANTARES Collaboration, The TANAMI Collaboration, Institut Universitaire de Technologie de Colmar-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA)), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), KM3NeT (IHEF, IoP, FNWI), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-IUT de Colmar, Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA)), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Département de Physique des Particules (ex SPP) (DPhP), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Adrián Martínez, S., Albert, A., André, M., Anton, G., Ardid, M., Aubert, J. J., Baret, B., Barrios, J., Basa, S., Bertin, V., Biagi, S., Bogazzi, C., Bormuth, R., Bou Cabo, M., Bouwhuis, M. C., Bruijn, R., Brunner, J., Busto, J., Capone, A., Caramete, L., Carr, J., Chiarusi, T., Circella, M., Coniglione, R., Costantini, H., Coyle, P., Creusot, A., DE ROSA, Gianfranca, Dekeyser, I., Deschamps, A., De Bonis, G., Distefano, C., Donzaud, C., Dornic, D., Dorosti, Q., Drouhin, D., Dumas, A., Eberl, T., Enzenhöfer, A., Escoffier, S., Fehn, K., Felis, I., Fermani, P., Folger, F., Fusco, L. A., Galatà, S., Gay, P., Geißelsöder, S., Geyer, K., Giordano, V., Gleixner, A., Gómez González, J. P., Gracia Ruiz, R., Graf, K., van Haren, H., Heijboer, A. J., Hello, Y., Hernández Rey, J. J., Herrero, A., Hößl, J., Hofestädt, J., Hugon, C., W. James, C., de Jong, M., Kalekin, O., Katz, U., Kießling, D., Kooijman, P., Kouchner, A., Kulikovskiy, V., Lahmann, R., Lattuada, D., Lefèvre, D., Leonora, E., Loehner, H., Loucatos, S., Mangano, S., Marcelin, M., Margiotta, A., Martínez Mora, J. A., Martini, S., Mathieu, A., Michael, T., Migliozzi, P., Neff, M., Nezri, E., Palioselitis, D., Păvălaş, G. E., Perrina, C., Piattelli, P., Popa, V., Pradier, T., Racca, C., Riccobene, G., Richter, R., Roensch, K., Rostovtsev, A., Saldaña, M., Samtleben, D. F. E., Sánchez Losa, A., Sanguineti, M., Sapienza, P., Schmid, J., Schnabel, J., Schulte, S., Schüssler, F., Seitz, T., Sieger, C., Spies, A., Spurio, M., Steijger, J. J. M., Stolarczyk, T. h., Taiuti, M., Tamburini, C., Tayalati, Y., Trovato, A., Tselengidou, M., Tönnis, C., Vallage, B., Vallée, C., Van Elewyck, V., Visser, E., Vivolo, Daniele, Wagner, S., de Wolf, E., Yepes, H., Zornoza, J. D., Zúñiga, J., Krauß, F., Kadler, M., Mannheim, K., Schulz, R., Trüstedt, J., Wilms, J., Ojha, R., Ros, E., Baumgartner, W., Beuchert, T., Blanchard, J., Bürkel, C., Carpenter, B., Edwards, P. G., Eisenacher Glawion, D., Elsässer, D., Fritsch, U., Gehrels, N., Gräfe, C., Großberger, C., Hase, H., Horiuchi, S., Kappes, A., Kreikenbohm, A., Kreykenbohm, I., Langejahn, M., Leiter, K., Litzinger, E., Lovell, J. E. J., Müller, C., Phillips, C., Plötz, C., Quick, J., Steinbring, T., Stevens, J., Thompson, D. J., Tzioumis, A. K., Adrian-Martinez, S, Albert, A, Andre, M, Anton, G, Ardid, M, Aubert, Jj, Baret, B, Barrios, J, Basa, S, Bertin, V, Biagi, S, Bogazzi, C, Bormuth, R, Bou-Cabo, M, Bouwhuis, Mc, Brujin, R, Brunner, J, Busto, J, Capone, A, Caramete, L, Cane, J, Chiarusim, T, Circella, M, Coniglione, R, Costantini, H, Coyle, P, Creusot, A, De Rosa, G, Dekeyser, I, Deschamps, A, De Bonis, G, Distefano, C, Donzaud, C, Dornic, D, Dorosti, Q, Drouhin, D, Dumas, A, Eberl, T, Enzenhofer, A, Escoffier, S, Fehn, K, Felis, I, Fermani, P, Folger, F, Fusco, La, Galata, S, Gay, P, Geisselsoder, S, Geyer, K, Giordano, V, Gleixner, A, Gomez-Gonzalez, Jp, Gracia-Ruiz, R, Graf, K, van Haren, H, Heijboer, Aj, Hello, Y, Hernandez-Rey, Jj, Herrero, A, Hossl, J, Hofestadt, J, Hugon, C, James, Cw, de Jong, M, Kalekin, O, Katz, U, Kiessling, D, Kooijman, P, Kouchner, A, Kulikovskiy, V, Lahmann, R, Lattuada, D, Lefevre, D, Leonora, E, Loehner, H, Loucatos, S, Mangano, S, Marcelin, M, Margiotta, A, Martinez-Mora, Ja, Martini, S, Mathieu, A, Michael, T, Migliozzi, P, Neff, M, Nezri, E, Palioselitis, D, Pavalas, Ge, Perrina, C, Piattelli, P, Popa, V, Pradier, T, Racca, C, Riccobene, G, Richter, R, Roensch, K, Rostovtsev, A, Saldana, M, Samtleben, Dfe, Sanchez-Losa, A, Sanguineti, M, Sapienza, P, Schmid, J, Schnabel, J, Schulte, S, Schussler, F, Seitz, T, Sieger, C, Spies, A, Spurio, M, Steijger, Jjm, Stolarczyk, T, Taiuti, M, Tamburini, C, Tayalati, Y, Trovato, A, Tselengidou, M, Tonnis, C, Vallage, B, Vallee, C, Van Elewyck, V, Visser, E, Vivolo, D, Wagner, S, de Wolf, E, Yepes, H, Zornoza, Jd, Zuniga, J, Krauss, F, Kadler, M, Mannheim, K, Schulz, R, Trustedt, J, Wilms, J, Ojha, R, Ros, E, Baumgartner, W, Beuchert, T, Blanchard, J, Burke, C, Carpenter, B, Edwards, Pg, Glawion, De, Elsasser, D, Fritsch, U, Gehrels, N, Grafe, C, Grossberger, C, Hase, H, Horiuchi, S, Kappes, A, Kreikenbohm, A, Kreykenbohm, I, Langejahn, M, Leiter, K, Litzinger, E, Lovell, Jej, Muller, C, Phillips, C, Plotz, C, Quick, J, Steinbring, T, Stevens, J, Thompson, Dj, Tzioumis, Ak, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Adrián-Martínez, S, Aubert, J.-J., Bou-Cabo, M., Bouwhuis, M.C., De Rosa, G., Fusco, L.A., Gómez-González, J.P., Gracia-Ruiz, R., Van Haren, H., Heijboer, A.J., Hernández-Rey, J.J., James, C.W., De Jong, M., Martínez-Mora, J.A., Pəvəlaş, G.E., Samtleben, D.F.E., Sánchez-Losa, A., Steijger, J.J.M., Stolarczyk, Th., Vivolo, D., De Wolf, E., Zornoza, J.D., Edwards, P.G., Lovell, J.E.J., Thompson, D.J., Tzioumis, A.K., Centre Tecnològic de Vilanova i la Geltrú, Universitat Politècnica de Catalunya. LAB - Laboratori d'Aplicacions Bioacústiques, Adrian-Martinez, S., Andre, M., Aubert, J. -J., Enzenhofer, A., Galata, S., Geisselsoder, S., Gomez-Gonzalez, J. P., Hernandez-Rey, J. J., Hossl, J., Hofestadt, J., James, C. W., Kiessling, D., Lefevre, D., Martinez-Mora, J. A., Pevelas, G. E., Saldana, M., Sanchez-Losa, A., Schussler, F., Tonnis, C., Vallee, C., Zuniga, J., Krauss, F., Trustedt, J., Burkel, C., Elsasser, D., Grafe, C., Grossberger, C., Muller, C., and Plotz, C.

Subjects
Astrofísica, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Monte Carlo method, Flux, FOS: Physical sciences, Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 7. Clean energy, 01 natural sciences, Spectral line, 0103 physical sciences, Neutrino, Galaxies: active, Neutrinos, Quasars: general, Neutrins, Blazar, 010303 astronomy & astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Muon, Cosmologia, 010308 nuclear & particles physics, Física, Astronomy and Astrophysics, general [Quasars], Astronomy and Astrophysic, Neutrino astrophysics, Quasars general, Cosmology, neutrinos – galaxies: active – quasars: general, Space and Planetary Science, Galaxies active, Col·lisions (Física nuclear), Física::Astronomia i astrofísica [Àrees temàtiques de la UPC], FISICA APLICADA, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena, MATEMATICA APLICADA, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Event (particle physics)
Abstract

Context. The source(s) of the neutrino excess reported by the IceCube Collaboration is unknown. The TANAMI Collaboration recently reported on the multiwavelength emission of six bright, variable blazars which are positionally coincident with two of the most energetic IceCube events. Objects like these are prime candidates to be the source of the highest-energy cosmic rays, and thus of associated neutrino emission. Aims. We present an analysis of neutrino emission from the six blazars using observations with the ANTARES neutrino telescope. Methods. The standard methods of the ANTARES candidate list search are applied to six years of data to search for an excess of muons and hence their neutrino progenitors from the directions of the six blazars described by the TANAMI Collaboration, and which are possibly associated with two IceCube events. Monte Carlo simulations of the detector response to both signal and background particle fluxes are used to estimate the sensitivity of this analysis for different possible source neutrino spectra. A maximum-likelihood approach, using the reconstructed energies and arrival directions of through-going muons, is used to identify events with properties consistent with a blazar origin. Results. Both blazars predicted to be the most neutrino-bright in the TANAMI sample (1653-329 and 1714-336) have a signal flux fitted by the likelihood analysis corresponding to approximately one event. This observation is consistent with the blazar-origin hypothesis of the IceCube event IC 14 for a broad range of blazar spectra, although an atmospheric origin cannot be excluded. No ANTARES events are observed from any of the other four blazars, including the three associated with IceCube event IC20. This excludes at a 90% confidence level the possibility that this event was produced by these blazars unless the neutrino spectrum is flatter than -2.4., The authors would like to thank A. Kappes for helpful discussions regarding the IceCube analysis. The ANTARES authors acknowledge the financial support of the funding agencies: Centre National de la Recherche Scientifique (CNRS), Commissariat a l'enegie atomique et aux energies alternatives (CEA), Commission Europeenne (FEDER fund and Marie Curie Program), Region Alsace (contrat CPER), Region Provence-Alpes-Cote d'Azur, Departement du Var and Ville de La Seyne-sur-Mer, France; Bundesministerium fur Bildung und Forschung (BMBF), Germany; Istituto Nazionale di Fisica Nucleare (INFN), Italy; Stichting voor Fundamenteel Onderzoek der Materie (FOM), Nederlandse organisatie voor Wetenschappelijk Onderzoek (NWO), the Netherlands; Council of the President of the Russian Federation for young scientists and leading scientific schools supporting grants, Russia; National Authority for Scientific Research (ANCS), Romania; Ministerio de Ciencia e Innovacion (MICINN), Prometeo of Generalitat Valenciana and MultiDark, Spain; Agence de l'Oriental and CNRST, Morocco. We also acknowledge the technical support of Ifremer, AIM and Foselev Marine for the sea operation and the CC-IN2P3 for the computing facilities. The TANAMI authors acknowledge support and partial funding by the Deutsche Forschungsgemeinschaft grant WI 1860-10/1 (TANAMI) and GRK 1147, Deutsches Zentrum fur Luft- und Raumfahrt grant 50 OR1311/50 OR1303/50 OR1401, the Spanish MINECO project AYA2012-38491-C02-01, the Generalitat Valenciana project PROMETEOII/2014/057, the COST MP0905 action "Black Holes in a Violent Universe" and the Helmholtz Alliance for Astroparticle Physics (HAP).

Published
2015
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13. Unusual flaring activity in the blazar PKS 1424-418 during 2008-2011

Author

Matthias Kadler, Lars Fuhrmann, Philip G. Edwards, R. Desiante, M. Dutka, Stephan Wagner, Jay Blanchard, Jamie Stevens, James E. J. Lovell, S. Cutini, Roopesh Ojha, Justin D. Finke, Filippo D'Ammando, D. J. Thompson, M. Hauser, Davide Donato, Francesco Longo, Cornelia Müller, Ann E. Wehrle, Mark Gurwell, S. Buson, Emmanouil Angelakis, J. A. Zensus, Denis Bastieri, A. Zook, Stefan Larsson, Stefano Ciprini, Buson, S., Longo, Francesco, Larsson, S., Cutini, S., Finke, J., Ciprini, S., Ojha, R., D'Ammando, F., Donato, D., Thompson, D. J., Desiante, R., Bastieri, D., Wagner, S., Hauser, M., Fuhrmann, L., Dutka, M., Muller, C., Kadler, M., Angelakis, E., Zensus, J. A., Stevens, J., Blanchard, J. M., Edwards, P. G., Lovell, J. E. J., Gurwell, M. A., Wehrle, A. E., Zook, A., Buson S, Longo F, Larsson S, Cutini S, Finke J, Ciprini S, Ojha R, DAmmando F, Donato D, Thompson DJ, Desiante R, Bastieri D, Wagner S, Hauser M, Fuhrmann L, Dutka M, Muller C, Kadler M, Angelakis E, Zensus JA, Stevens J, Blanchard JM, Edwards PG, Lovell JEJ, Gurwell MA, Wehrle AE, and Zook A

Subjects
Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, law.invention, Telescope, law, gamma rays: galaxies, Blazar, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), galaxies: active / radiation mechanisms: non-thermal / quasars: individual: PKS 1424-418 / gamma rays: galaxies / galaxies: jets, Line-of-sight, quasars: individual: PKS 1424-418, Astronomy and Astrophysics, active, radiation mechanisms: non-thermal, quasars: individual: PKS 1424-418, gamma rays: galaxies, galaxies: jets [galaxies], radiation mechanisms: non-thermal, galaxies: jets, Space and Planetary Science, galaxies: active, radiation mechanisms: non-thermal, quasars: individual: PKS 1424-418, gamma rays: galaxies, galaxies: jets, Spectral energy distribution, Astrophysics - High Energy Astrophysical Phenomena, Flare, Fermi Gamma-ray Space Telescope
Abstract

Context. Blazars are a subset of active galactic nuclei (AGN) with jets that are oriented along our line of sight. Variability and spectral energy distribution (SED) studies are crucial tools for understanding the physical processes responsible for observed AGN emission. Aims. We report peculiar behaviour in the bright gamma-ray blazar PKS 1424-418 and use its strong variability to reveal information about the particle acceleration and interactions in the jet. Methods. Correlation analysis of the extensive optical coverage by the ATOM telescope and nearly continuous gamma-ray coverage by the Fermi Large Area Telescope is combined with broadband, time-dependent modeling of the SED incorporating supplemental information from radio and X-ray observations of this blazar. Results. We analyse in detail four bright phases at optical-GeV energies. These flares of PKS 1424-418 show high correlation between these energy ranges, with the exception of one large optical flare that coincides with relatively low gamma-ray activity. Although the optical/gamma-ray behaviour of PKS 1424-418 shows variety, the multiwavelength modeling indicates that these differences can largely be explained by changes in the flux and energy spectrum of the electrons in the jet that are radiating. We find that for all flares the SED is adequately represented by a leptonic model that includes inverse Compton emission from external radiation fields with similar parameters. Conclusions. Detailed studies of individual blazars like PKS 1424-418 during periods of enhanced activity in different wavebands are helping us identify underlying patterns in the physical parameters in this class of AGN., accepted for publication in A&A

Published
2014

14. The AUSTRAL VLBI observing program.

Author

Plank L, Lovell JEJ, McCallum JN, Mayer D, Reynolds C, Quick J, Weston S, Titov O, Shabala SS, Böhm J, Natusch T, Nickola M, and Gulyaev S

Abstract

The AUSTRAL observing program was started in 2011, performing geodetic and astrometric very long baseline interferometry (VLBI) sessions using the new Australian AuScope VLBI antennas at Hobart, Katherine, and Yarragadee, with contribution from the Warkworth (New Zealand) 12 m and Hartebeesthoek (South Africa) 15 m antennas to make a southern hemisphere array of telescopes with similar design and capability. Designed in the style of the next-generation VLBI system, these small and fast antennas allow for a new way of observing, comprising higher data rates and more observations than the standard observing sessions coordinated by the International VLBI Service for Geodesy and Astrometry (IVS). In this contribution, the continuous development of the AUSTRAL sessions is described, leading to an improvement of the results in terms of baseline length repeatabilities by a factor of two since the start of this program. The focus is on the scheduling strategy and increased number of observations, aspects of automated operation, and data logistics, as well as results of the 151 AUSTRAL sessions performed so far. The high number of the AUSTRAL sessions makes them an important contributor to VLBI end-products, such as the terrestrial and celestial reference frames and Earth orientation parameters. We compare AUSTRAL results with other IVS sessions and discuss their suitability for the determination of baselines, station coordinates, source coordinates, and Earth orientation parameters., (© The Author(s) 2016.)

Published
2017
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15. Overview and initial results of the very long baseline interferometry space observatory programme

Author

Hirabayashi H, Hirosawa H, Kobayashi H, Murata Y, Edwards PG, Fomalont EB, Fujisawa K, Ichikawa T, Kii T, Lovell JEJ, Moellenbrock GA, Okayasu R, Inoue M, Kawaguchi N, Kameno S, Shibata KM, Asaki Y, Bushimata T, Enome S, Horiuchi S, Miyaji T, Umemoto T, Migenes V V, Wajima K, Nakajima J, Morimoto M, Ellis J, Meier DL, Murphy DW, Preston RA, Smith JG, Tingay SJ, Traub DL, Wietfeldt RD, Benson JM, Claussen MJ, Flatters C, Romney JD, Ulvestad JS, D’Addario LR, Langston GI, Minter AH, Carlson BR, Dewdney PE, Jauncey DL, Reynold JE, Taylor AR, McCulloch PM, Cannon WH, Gurvits LI, Mioduszewski AJ, Schilizzi RT, and Booth RS

Abstract

High angular resolution images of extragalactic radio sources are being made with the Highly Advanced Laboratory for Communications and Astronomy (HALCA) satellite and ground-based radio telescopes as part of the Very Long Baseline Interferometry (VLBI) Space Observatory Programme (VSOP). VSOP observations at 1.6 and 5 gigahertz of the milli-arc-second-scale structure of radio quasars enable the quasar core size and the corresponding brightness temperature to be determined, and they enable the motions of jet components that are close to the core to be studied. Here, VSOP images of the gamma-ray source 1156+295, the quasar 1548+056, the ultraluminous quasar 0014+813, and the superluminal quasar 0212+735 are presented and discussed.

Published
1998
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