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985 results on '"McKean, J."'

162. Cassiopeia A, Cygnus A, Taurus A, and Virgo A at ultra-low radio frequencies

Author

de Gasperin, F., primary, Vink, J., additional, McKean, J. P., additional, Asgekar, A., additional, Avruch, I., additional, Bentum, M. J., additional, Blaauw, R., additional, Bonafede, A., additional, Broderick, J. W., additional, Brüggen, M., additional, Breitling, F., additional, Brouw, W. N., additional, Butcher, H. R., additional, Ciardi, B., additional, Cuciti, V., additional, de Vos, M., additional, Duscha, S., additional, Eislöffel, J., additional, Engels, D., additional, Fallows, R. A., additional, Franzen, T. M. O., additional, Garrett, M. A., additional, Gunst, A. W., additional, Hörandel, J., additional, Heald, G., additional, Hoeft, M., additional, Iacobelli, M., additional, Koopmans, L. V. E., additional, Krankowski, A., additional, Maat, P., additional, Mann, G., additional, Mevius, M., additional, Miley, G., additional, Morganti, R., additional, Nelles, A., additional, Norden, M. J., additional, Offringa, A. R., additional, Orrú, E., additional, Paas, H., additional, Pandey, V. N., additional, Pandey-Pommier, M., additional, Pekal, R., additional, Pizzo, R., additional, Reich, W., additional, Rowlinson, A., additional, Rottgering, H. J. A., additional, Schwarz, D. J., additional, Shulevski, A., additional, Smirnov, O., additional, Sobey, C., additional, Soida, M., additional, Steinmetz, M., additional, Tagger, M., additional, Toribio, M. C., additional, van Ardenne, A., additional, van der Horst, A. J., additional, van Haarlem, M. P., additional, van Weeren, R. J., additional, Vocks, C., additional, Wucknitz, O., additional, Zarka, P., additional, and Zucca, P., additional

Published
2020
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166. Corrigendum: A large light-mass component of cosmic rays at 10171017.5 electronvolts from radio observations

Author

Buitink, S., Corstanje, A., Falcke, H., Hrandel, J. R., Huege, T., Nelles, A., Rachen, J. P., Rossetto, L., Schellart, P., Scholten, O., ter Veen, S., Thoudam, S., Trinh, T. N. G., Anderson, J., Asgekar, A., Avruch, I. M., Bell, M. E., Bentum, M. J., Bernardi, G., Best, P., Bonafede, A., Breitling, F., Broderick, J. W., Brouw, W. N., Brggen, M., Butcher, H. R., Carbone, D., Ciardi, B., Conway, J. E., de Gasperin, F., de Geus, E., Deller, A., Dettmar, R.-J., van Diepen, G., Duscha, S., Eislffel, J., Engels, D., Enriquez, J. E., Fallows, R. A., Fender, R., Ferrari, C., Frieswijk, W., Garrett, M. A., Griemeier, J. M., Gunst, A. W., van Haarlem, M. P., Hassall, T. E., Heald, G., Hessels, J. W. T., Hoeft, M., Horneffer, A., Iacobelli, M., Intema, H., Juette, E., Karastergiou, A., Kondratiev, V. I., Kramer, M., Kuniyoshi, M., Kuper, G., van Leeuwen, J., Loose, G. M., Maat, P., Mann, G., Markoff, S., McFadden, R., McKay-Bukowski, D., McKean, J. P., Mevius, M., Mulcahy, D. D., Munk, H., Norden, M. J., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V. N., Pietka, M., Pizzo, R., Polatidis, A. G., Reich, W., Rttgering, H. J. A., Scaife, A. M. M., Schwarz, D. J., Serylak, M., Sluman, J., Smirnov, O., Stappers, B. W., Steinmetz, M., Stewart, A., Swinbank, J., Tagger, M., Tang, Y., Tasse, C., Toribio, M. C., Vermeulen, R., Vocks, C., Vogt, C., van Weeren, R. J., Wijers, R. A. M. J., Wijnholds, S. J., Wise, M. W., Wucknitz, O., Yatawatta, S., Zarka, P., and Zensus, J. A.

Subjects
Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Author(s): S. Buitink; A. Corstanje; H. Falcke; J. R. Hrandel; T. Huege; A. Nelles; J. P. Rachen; L. Rossetto; P. Schellart; O. Scholten; S. ter Veen; S. Thoudam; T. N. [...]

Published
2016
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170. High Time Resolution with LOFAR

Author

Hessels, J., Fallows, R., Heald, G., McKean, J., Pizzo, R., and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Pipeline (computing), Astrophysics::Instrumentation and Methods for Astrophysics, Polarimetry, Astrophysics, LOFAR, 01 natural sciences, Spectral line, law.invention, Stars, Pulsar, Planet, law, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Flare
Abstract

LOFAR achieves high time resolution (

Published
2018

171. Calibration of LOFAR

Author

McKean, John, de Bruyn, Ger, Heald, G., McKean, J, Pizzo, R., and Astronomy

Subjects
Software, business.industry, Physics, ComputerApplications_MISCELLANEOUS, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Calibration, Astronomical interferometer, LOFAR, Visibility, business, Remote sensing
Abstract

Calibrating the raw visibility data from radio interferometers in order to remove the effects of the instrument and the atmosphere is needed to achieve the desired scientific outcome. Here, the processes required to calibrate data from LOFAR, after applying the pre-processing steps, are discussed. In particular, the calibration philosophy and usage of the LOFAR calibration software is discussed in detail.

Published
2018
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175. The LOFAR Two-metre Sky Survey

Author

Shimwell, T. W., primary, Tasse, C., additional, Hardcastle, M. J., additional, Mechev, A. P., additional, Williams, W. L., additional, Best, P. N., additional, Röttgering, H. J. A., additional, Callingham, J. R., additional, Dijkema, T. J., additional, de Gasperin, F., additional, Hoang, D. N., additional, Hugo, B., additional, Mirmont, M., additional, Oonk, J. B. R., additional, Prandoni, I., additional, Rafferty, D., additional, Sabater, J., additional, Smirnov, O., additional, van Weeren, R. J., additional, White, G. J., additional, Atemkeng, M., additional, Bester, L., additional, Bonnassieux, E., additional, Brüggen, M., additional, Brunetti, G., additional, Chyży, K. T., additional, Cochrane, R., additional, Conway, J. E., additional, Croston, J. H., additional, Danezi, A., additional, Duncan, K., additional, Haverkorn, M., additional, Heald, G. H., additional, Iacobelli, M., additional, Intema, H. T., additional, Jackson, N., additional, Jamrozy, M., additional, Jarvis, M. J., additional, Lakhoo, R., additional, Mevius, M., additional, Miley, G. K., additional, Morabito, L., additional, Morganti, R., additional, Nisbet, D., additional, Orrú, E., additional, Perkins, S., additional, Pizzo, R. F., additional, Schrijvers, C., additional, Smith, D. J. B., additional, Vermeulen, R., additional, Wise, M. W., additional, Alegre, L., additional, Bacon, D. J., additional, van Bemmel, I. M., additional, Beswick, R. J., additional, Bonafede, A., additional, Botteon, A., additional, Bourke, S., additional, Brienza, M., additional, Calistro Rivera, G., additional, Cassano, R., additional, Clarke, A. O., additional, Conselice, C. J., additional, Dettmar, R. J., additional, Drabent, A., additional, Dumba, C., additional, Emig, K. L., additional, Enßlin, T. A., additional, Ferrari, C., additional, Garrett, M. A., additional, Génova-Santos, R. T., additional, Goyal, A., additional, Gürkan, G., additional, Hale, C., additional, Harwood, J. J., additional, Heesen, V., additional, Hoeft, M., additional, Horellou, C., additional, Jackson, C., additional, Kokotanekov, G., additional, Kondapally, R., additional, Kunert-Bajraszewska, M., additional, Mahatma, V., additional, Mahony, E. K., additional, Mandal, S., additional, McKean, J. P., additional, Merloni, A., additional, Mingo, B., additional, Miskolczi, A., additional, Mooney, S., additional, Nikiel-Wroczyński, B., additional, O’Sullivan, S. P., additional, Quinn, J., additional, Reich, W., additional, Roskowiński, C., additional, Rowlinson, A., additional, Savini, F., additional, Saxena, A., additional, Schwarz, D. J., additional, Shulevski, A., additional, Sridhar, S. S., additional, Stacey, H. R., additional, Urquhart, S., additional, van der Wiel, M. H. D., additional, Varenius, E., additional, Webster, B., additional, and Wilber, A., additional

Published
2019
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176. The LOFAR Two-metre Sky Survey

Author

Williams, W. L., primary, Hardcastle, M. J., additional, Best, P. N., additional, Sabater, J., additional, Croston, J. H., additional, Duncan, K. J., additional, Shimwell, T. W., additional, Röttgering, H. J. A., additional, Nisbet, D., additional, Gürkan, G., additional, Alegre, L., additional, Cochrane, R. K., additional, Goyal, A., additional, Hale, C. L., additional, Jackson, N., additional, Jamrozy, M., additional, Kondapally, R., additional, Kunert-Bajraszewska, M., additional, Mahatma, V. H., additional, Mingo, B., additional, Morabito, L. K., additional, Prandoni, I., additional, Roskowinski, C., additional, Shulevski, A., additional, Smith, D. J. B., additional, Tasse, C., additional, Urquhart, S., additional, Webster, B., additional, White, G. J., additional, Beswick, R. J., additional, Callingham, J. R., additional, Chyży, K. T., additional, de Gasperin, F., additional, Harwood, J. J., additional, Hoeft, M., additional, Iacobelli, M., additional, McKean, J. P., additional, Mechev, A. P., additional, Miley, G. K., additional, Schwarz, D. J., additional, and van Weeren, R. J., additional

Published
2019
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177. LoTSS/HETDEX: Disentangling star formation and AGN activity in gravitationally lensed radio-quiet quasars

Author

Stacey, H. R., primary, McKean, J. P., additional, Jackson, N. J., additional, Best, P. N., additional, Calistro Rivera, G., additional, Callingham, J. R., additional, Duncan, K. J., additional, Gürkan, G., additional, Hardcastle, M. J., additional, Iacobelli, M., additional, Mechev, A. P., additional, Morabito, L. K., additional, Prandoni, I., additional, Röttgering, H. J. A., additional, Sabater, J., additional, Shimwell, T. W., additional, Tasse, C., additional, and Williams, W. L., additional

Published
2019
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178. Observational constraints on the sub-galactic matter-power spectrum from galaxy-galaxy strong gravitational lensing

Author

Bayer, D., Chatterjee, S., Koopmans, L. V. E., Vegetti, S., McKean, J. P., Treu, T., Fassnacht, C. D., Bayer, D., Chatterjee, S., Koopmans, L. V. E., Vegetti, S., McKean, J. P., Treu, T., and Fassnacht, C. D.

Abstract

Constraining the sub-galactic matter-power spectrum on 1-10 kpc scales would make it possible to distinguish between the concordance $\Lambda$CDM model and various alternative dark-matter models due to the significantly different levels of predicted mass structure. Here, we demonstrate a novel approach to observationally constrain the population of overall law-mass density fluctuations in the inner regions of massive elliptical lens galaxies, based on the power spectrum of the associated surface-brightness perturbations observable in highly magnified galaxy-scale Einstein rings and gravitational arcs. The application of our method to the SLACS lens system SDSS J0252+0039 results in the following limits (at the 99 per cent confidence level) on the dimensionless convergence-power spectrum (and the associated standard deviation in aperture mass): $\Delta^{2}_{\delta\kappa}<1$ ($\sigma_{AM}< 0.8 \times 10^8 M_\odot$) on 0.5-kpc scale, $\Delta^{2}_{\delta\kappa}<0.1$ ($\sigma_{AM}< 1 \times 10^8 M_\odot$) on 1-kpc scale and $\Delta^{2}_{\delta\kappa}<0.01$ ($\sigma_{AM}< 3 \times 10^8 M_\odot$) on 3-kpc scale. The estimated effect of CDM sub-haloes lies considerably below these first observational upper-limit constraints on the level of inhomogeneities in the projected total mass distribution of galactic haloes. Future analysis for a larger sample of galaxy-galaxy strong lens systems will narrow down these constraints and rule out all cosmological models predicting a significantly larger level of clumpiness on these critical sub-galactic scales.

Published
2018

179. Low-frequency radio absorption in Cassiopeia A

Author

Arias, M., Vink, J., de Gasperin, F., Salas, P., Oonk, J. B. R., van Weeren, R. J., van Amesfoort, A. S., Anderson, J., Beck, R., Bell, M. E., Bentum, M. J., Best, P., Blaauw, R., Breitling, F., Broderick, J. W., Brouw, W. N., Brueggen, M., Butcher, H. R., Ciardi, B., de Geus, E., Deller, A., van Dijk, P. C. G., Duscha, S., Eisloeffel, J., Garrett, M. A., Griessmeier, J. M., Gunst, A. W., van Haarlem, M. P., Heald, G., Hessels, J., Horandel, J., Holties, H. A., van der Horst, A. J., Iacobelli, M., Juette, E., Krankowski, A., van Leeuwen, J., Mann, G., McKay-Bukowski, D., McKean, J. P., Mulder, H., Nelles, A., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V. N., Pekal, R., Pizzo, R., Polatidis, A. G., Reich, W., Rottgering, H. J. A., Rothkaehl, H., Schwarz, D. J., Smirnov, O., Soida, M., Steinmetz, M., Tagger, M., Thoudam, Satyendra, Toribio, M. C., Vocks, C., van der Wiel, M. H. D., Wijers, R. A. M. J., Wucknitz, O., Zarka, P., Zucca, P., Arias, M., Vink, J., de Gasperin, F., Salas, P., Oonk, J. B. R., van Weeren, R. J., van Amesfoort, A. S., Anderson, J., Beck, R., Bell, M. E., Bentum, M. J., Best, P., Blaauw, R., Breitling, F., Broderick, J. W., Brouw, W. N., Brueggen, M., Butcher, H. R., Ciardi, B., de Geus, E., Deller, A., van Dijk, P. C. G., Duscha, S., Eisloeffel, J., Garrett, M. A., Griessmeier, J. M., Gunst, A. W., van Haarlem, M. P., Heald, G., Hessels, J., Horandel, J., Holties, H. A., van der Horst, A. J., Iacobelli, M., Juette, E., Krankowski, A., van Leeuwen, J., Mann, G., McKay-Bukowski, D., McKean, J. P., Mulder, H., Nelles, A., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V. N., Pekal, R., Pizzo, R., Polatidis, A. G., Reich, W., Rottgering, H. J. A., Rothkaehl, H., Schwarz, D. J., Smirnov, O., Soida, M., Steinmetz, M., Tagger, M., Thoudam, Satyendra, Toribio, M. C., Vocks, C., van der Wiel, M. H. D., Wijers, R. A. M. J., Wucknitz, O., Zarka, P., and Zucca, P.

Abstract

Context. Cassiopeia A is one of the best-studied supernova remnants. Its bright radio and X-ray emission is due to shocked ejecta. Cas A is rather unique in that the unshocked ejecta can also be studied: through emission in the infrared, the radio-active decay of Ti-44, and the low-frequency free-free absorption caused by cold ionised gas, which is the topic of this paper. Aims. Free-free absorption processes are affected by the mass, geometry, temperature, and ionisation conditions in the absorbing gas. Observations at the lowest radio frequencies can constrain a combination of these properties. Methods. We used Low Frequency Array (LOFAR) Low Band Antenna observations at 30-77 MHz and Very Large Array (VLA) L-band observations at 1-2 GHz to fit for internal absorption as parametrised by the emission measure. We simultaneously fit multiple UV-matched images with a common resolution of 17 '' (this corresponds to 0.25 pc for a source at the distance of Cas A). The ample frequency coverage allows us separate the relative contributions from the absorbing gas, the unabsorbed front of the shell, and the absorbed back of the shell to the emission spectrum. We explored the effects that a temperature lower than the similar to 100-500 K proposed from infrared observations and a high degree of clumping can have on the derived physical properties of the unshocked material, such as its mass and density. We also compiled integrated radio flux density measurements, fit for the absorption processes that occur in the radio band, and considered their effect on the secular decline of the source. Results. We find a mass in the unshocked ejecta of M = 2.95 +/- 0.48 M-circle dot for an assumed gas temperature of T = 100 K. This estimate is reduced for colder gas temperatures and, most significantly, if the ejecta are clumped. We measure the reverse shock to have a radius of 114 '' +/- 6 '' and be centred at 23:23:26, +58:48:54 (J2000). We also find that a decrease in the amount of mass

Published
2018
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180. LOFAR reveals the giant: A low-frequency radio continuum study of the outflow in the nearby FR I radio galaxy 3C 31

Author

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

Abstract

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 1.1Mpc in projection, which means 3C 31 now falls in the class of giant radio galaxies. We model the radio continuum intensitieswith 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 a rß (ß ˜ -1). This then compensates for the strong adiabatic losses due to the lateral expansion of the tails. We are able to find selfconsistent 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.

Published
2018

181. A hierarchical modelling framework for assessing physical and biochemical characteristics of a regulated river

Author

Tranmer, A., Marti, Clelia, Tonina, D., Benjankar, R., Weigel, D., Vilhena, L., McGrath, C., Goodwin, P., Tiedemann, M., Mckean, J., Imberger, J., Tranmer, A., Marti, Clelia, Tonina, D., Benjankar, R., Weigel, D., Vilhena, L., McGrath, C., Goodwin, P., Tiedemann, M., Mckean, J., and Imberger, J.

Abstract

© 2017 Elsevier B.V. Regulated rivers below dams have traditionally been managed using a minimum instream flow to provide adequate aquatic habitat. However, dam management, in conjunction with changes in climate and land use, challenges downstream ecosystem functions that cannot be properly addressed by a simple minimum flow requirement. Depending upon the river system, additional parameters such as water temperature and nutrient loading provide more critical ecological value for organisms than ensuring a constant minimum release. A new modelling methodology, utilizing a cascading hierarchical approach, is proposed and tested on a 614 km 2 headwater basin in central Idaho, USA. Application of the methodology illustrates that below large dams the river discharge becomes independent of the seasonal hydrology and specifying the discharge alone is insufficient for evaluating ecosystem response. Upstream reservoirs interrupt the watershed continuum and internally modify the thermal, chemical, and biological properties of water prior to release into a downstream river. These water properties depend on the annual hydrologic regime, characteristics of the reservoir and the offtake strategies, offtake structure depth, dam discharge, and the water column thermal stratification. This study describes the use of climatically driven hydrologic forcing and variable dam operations in a coupled reservoir-river system to optimize river ecosystem health by linking physical processes with in situ observations and incorporating multi-trophic species requirements. Such an approach can support real-time decision making on existing reservoir-river systems and provide a virtual means of evaluating ecosystem impacts prior to disturbance from new dam construction or implementation of restoration activities in a watershed.

Published
2018

182. The LOFAR Two-metre Sky Survey: I. Survey description and preliminary data release⋆

Author

Shimwell, T W, Röttgering, H J A, Best, P N, Williams, W L, Dijkema, T J, de Gasperin, F, Hardcastle, M J, Heald, G H, Hoang, D N, Horneffer, A, Intema, H, Mahony, E K, Mandal, S, Mechev, A P, Morabito, L, Oonk, J B R, Rafferty, D, Retana-Montenegro, E, Sabater, J, Tasse, C, van Weeren, R J, BrYggen, M, Brunetti, G, Chyży, K T, Conway, J E, Haverkorn, M, Jackson, N, Jarvis, M J, McKean, J P, Miley, G K, Morganti, R, White, G J, Department of Astronomy, and Faculty of Science

Subjects
Will, source, Strategy, Farm produce, Area, radio continuum: general, techniques: image processing, RADIO RECOMBINATION LINES, Imaging, quartier, surveys, evolution, emission, survey, prospection, table, time, stratégie, région, region, Galaxies--Clusters, paper, square, nucleus, Structure, Sources, Degrees, 1ST SURVEY, GALA, calibration, Galaxies, Description and travel, field, Spring, testament, Holes, Impact, Black, noir, valeur, line, catalogue, Sky, Noise, FOLLOW-UP, catalogs, Value
Abstract

598

Published
2017
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183. Remote sensing and landslide hazard assessment

Author

Mckean, J, Buechel, S, and Gaydos, L

Subjects
Earth Resources And Remote Sensing
Abstract

Remotely acquired multispectral data are used to improve landslide hazard assessments at all scales of investigation. A vegetation map produced from automated interpretation of TM data is used in a GIS context to explore the effect of vegetation type on debris flow occurrence in preparation for inclusion in debris flow hazard modeling. Spectral vegetation indices map spatial patterns of grass senescence which are found to be correlated with soil thickness variations on hillslopes. Grassland senescence is delayed over deeper, wetter soils that are likely debris flow source areas. Prediction of actual soil depths using vegetation indices may be possible up to some limiting depth greater than the grass rooting zone. On forested earthflows, the slow slide movement disrupts the overhead timber canopy, exposes understory vegetation and soils, and alters site spectral characteristics. Both spectral and textural measures from broad band multispectral data are successful at detecting an earthflow within an undisturbed old-growth forest.

Published
1991

184. Smoke on the water: CO and H2O in a circumnuclear disc around a quasar at redshift 2.64.

Author

Stacey, H R, Lafontaine, A, and McKean, J P

Subjects
QUASARS, VERY long baseline interferometry, ACTIVE galactic nuclei
Abstract

We present an analysis of observations with the Atacama Large (sub-)Millimetre Array (ALMA) of the 380 GHz water emission line and CO (11–10) emission line from MG J0414+0534, a gravitationally lensed dusty star-forming galaxy that hosts a type 1 quasar. We also present observations at 1.6 GHz with global very long baseline interferometry of the radio source. We confirm the previously reported detection of the 380 GHz water line and that the flux density ratio between the two merging lensed images is reversed with respect to the radio/mm continuum. We further find tentative evidence of variability in the integrated line intensity on time-scales of days. We show that the 380 GHz water line has two components of emission: a disc that is around 35 pc in diameter around the quasar, and another component of emission that is offset ∼600 pc perpendicular to the disc that lies close to the lensing caustic. With lens modelling of the multiwavelength data sets, we construct a model for the quasar system consisting of a circumnuclear disc of molecular gas with a size of about 60 pc bisected by radio jets extending to a distance of about 200 pc from the radio core. Our findings suggest that observations with ALMA of high-excitation molecular lines from strongly lensed quasars could allow detailed studies of active galactic nucleus accretion and feedback at the cosmic peak of black hole and galaxy growth. [ABSTRACT FROM AUTHOR]

Published
2020
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185. SHARP – VII. New constraints on the dark matter free-streaming properties and substructure abundance from gravitationally lensed quasars.

Author

Hsueh, J-W, Enzi, W, Vegetti, S, Auger, M W, Fassnacht, C D, Despali, G, Koopmans, L V E, and McKean, J P

Subjects
DARK matter, PROPERTIES of matter, QUASARS, CONFIDENCE intervals, SIMULATION methods & models, GRAVITATIONAL lenses
Abstract

We present an analysis of seven strongly gravitationally lensed quasars and the corresponding constraints on the properties of dark matter. Our results are derived by modelling the lensed image positions and flux-ratios using a combination of smooth macro-models and a population of low-mass haloes within the mass range of 106–109 M⊙. Our lens models explicitly include higher order complexity in the form of stellar discs and luminous satellites, as well as low-mass haloes located along the observed lines of sight for the first time. Assuming a cold dark matter (CDM) cosmology, we infer an average total mass fraction in substructure of |$f_{\rm sub} = 0.012^{+0.007}_{-0.004}$| (68 per cent confidence limits), which is in agreement with the predictions from CDM hydrodynamical simulations to within 1σ. This result is closer to the predictions than those from previous studies that did not include line-of-sight haloes. Under the assumption of a thermal relic dark matter model, we derive a lower limit on the particle relic mass of m th > 5.58 keV (95 per cent confidence limits), which is consistent with a value of m th > 5.3 keV from the recent analysis of the Ly α forest. We also identify two main sources of possible systematic errors and conclude that deeper investigations in the complex structure of lens galaxies as well as the size of the background sources should be a priority for this field. [ABSTRACT FROM AUTHOR]

Published
2020
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192. Low-frequency radio absorption in Cassiopeia A

Author

Arias, M., primary, Vink, J., additional, de Gasperin, F., additional, Salas, P., additional, Oonk, J. B. R., additional, van Weeren, R. J., additional, van Amesfoort, A. S., additional, Anderson, J., additional, Beck, R., additional, Bell, M. E., additional, Bentum, M. J., additional, Best, P., additional, Blaauw, R., additional, Breitling, F., additional, Broderick, J. W., additional, Brouw, W. N., additional, Brüggen, M., additional, Butcher, H. R., additional, Ciardi, B., additional, de Geus, E., additional, Deller, A., additional, van Dijk, P. C. G., additional, Duscha, S., additional, Eislöffel, J., additional, Garrett, M. A., additional, Grießmeier, J. M., additional, Gunst, A. W., additional, van Haarlem, M. P., additional, Heald, G., additional, Hessels, J., additional, Hörandel, J., additional, Holties, H. A., additional, van der Horst, A. J., additional, Iacobelli, M., additional, Juette, E., additional, Krankowski, A., additional, van Leeuwen, J., additional, Mann, G., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Mulder, H., additional, Nelles, A., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pandey, V. N., additional, Pekal, R., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Röttgering, H. J. A., additional, Rothkaehl, H., additional, Schwarz, D. J., additional, Smirnov, O., additional, Soida, M., additional, Steinmetz, M., additional, Tagger, M., additional, Thoudam, S., additional, Toribio, M. C., additional, Vocks, C., additional, van der Wiel, M. H. D., additional, Wijers, R. A. M. J., additional, Wucknitz, O., additional, Zarka, P., additional, and Zucca, P., additional

Published
2018
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193. The X-ray ribs within the cocoon shock of Cygnus A

Author

Duffy, R T, primary, Worrall, D M, additional, Birkinshaw, M, additional, Nulsen, P E J, additional, Wise, M W, additional, de Vries, M N, additional, Snios, B, additional, Mathews, W G, additional, Perley, R A, additional, Hardcastle, M J, additional, Rafferty, D A, additional, McNamara, B R, additional, Edge, A C, additional, McKean, J P, additional, Carilli, C L, additional, Croston, J H, additional, Godfrey, L E H, additional, and Laing, R A, additional

Published
2018
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194. Tracking of an electron beam through the solar corona with LOFAR

Author

Mann, G., primary, Breitling, F., additional, Vocks, C., additional, Aurass, H., additional, Steinmetz, M., additional, Strassmeier, K. G., additional, Bisi, M. M., additional, Fallows, R. A., additional, Gallagher, P., additional, Kerdraon, A., additional, Mackinnon, A., additional, Magdalenic, J., additional, Rucker, H., additional, Anderson, J., additional, Asgekar, A., additional, Avruch, I. M., additional, Bell, M. E., additional, Bentum, M. J., additional, Bernardi, G., additional, Best, P., additional, Bîrzan, L., additional, Bonafede, A., additional, Broderick, J. W., additional, Brüggen, M., additional, Butcher, H. R., additional, Ciardi, B., additional, Corstanje, A., additional, de Gasperin, F., additional, de Geus, E., additional, Deller, A., additional, Duscha, S., additional, Eislöffel, J., additional, Engels, D., additional, Falcke, H., additional, Fender, R., additional, Ferrari, C., additional, Frieswijk, W., additional, Garrett, M. A., additional, Grießmeier, J., additional, Gunst, A. W., additional, van Haarlem, M., additional, Hassall, T. E., additional, Heald, G., additional, Hessels, J. W. T., additional, Hoeft, M., additional, Hörandel, J., additional, Horneffer, A., additional, Juette, E., additional, Karastergiou, A., additional, Klijn, W. F. A., additional, Kondratiev, V. I., additional, Kramer, M., additional, Kuniyoshi, M., additional, Kuper, G., additional, Maat, P., additional, Markoff, S., additional, McFadden, R., additional, McKay-Bukowski, D., additional, McKean, J. P., additional, Mulcahy, D. D., additional, Munk, H., additional, Nelles, A., additional, Norden, M. J., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pandey, V. N., additional, Pizzo, R., additional, Polatidis, A. G., additional, Rafferty, D., additional, Reich, W., additional, Röttgering, H., additional, Scaife, A. M. M., additional, Schwarz, D. J., additional, Serylak, M., additional, Sluman, J., additional, Smirnov, O., additional, Stappers, B. W., additional, Tagger, M., additional, Tang, Y., additional, Tasse, C., additional, ter Veen, S., additional, Thoudam, S., additional, Toribio, M. C., additional, Vermeulen, R., additional, van Weeren, R. J., additional, Wise, M. W., additional, Wucknitz, O., additional, Yatawatta, S., additional, Zarka, P., additional, and Zensus, J. A., additional

Published
2018
Full Text
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