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1. The SARAO MeerKAT 1.3 GHz Galactic Plane Survey

Author

Goedhart, S., Cotton, W. D., Camilo, F., Thompson, M. A., Umana, G., Bietenholz, M., Woudt, P. A., Anderson, L. D., Bordiu, C., Buckley, D. A. H., Buemi, C. S., Bufano, F., Cavallaro, F., Chen, H., Chibueze, J. O., Egbo, D., Frank, B. S., Hoare, M. G., Ingallinera, A., Irabor, T., Kraan-Korteweg, R. C., Kurapati, S., Leto, P., Loru, S., Mutale, M., Obonyo, W. O., Plavin, A., Rajohnson, S. H. A., Rigby, A., Riggi, S., Seidu, M., Serra, P., Smart, B. M., Stappers, B. W., Steyn, N., Surnis, M., Trigilio, C., Williams, G. M., Abbott, T. D., Adam, R. M., Asad, K. M. B., Baloyi, T., Bauermeister, E. F., Bennet, T. G. H., Bester, H., Botha, A. G., Brederode, L. R. S., Buchner, S., Burger, J. P., Cheetham, T., Cloete, K., de Villiers, M. S., de Villiers, D. I. L., Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B. L., Fourie, D. J., Gamatham, R. R. G., Gatsi, T. G., Geyer, M., Gouws, M., Gumede, S. C., Heywood, I., Hokwana, A., Hoosen, S. W., Horn, D. M., Horrell, L. M. G., Hugo, B. V., Isaacson, A. I., Józsa, G. I. G., Jonas, J. L., Jordaan, J. D. B. L., Joubert, A. F., Julie, R. P. M., Kapp, F. B., Kriek, N., Kriel, H., Krishnan, V. K., Kusel, T. W., Legodi, L. S., Lehmensiek, R., Lord, R. T., Macfarlane, P. S., Magnus, L. G., Magozore, C., Main, J. P. L., Malan, J. A., Manley, J. R., Marais, S. J., Maree, M. D. J., Martens, A., Maruping, P., McAlpine, K., Merry, B. C., Mgodeli, M., Millenaar, R. P., Mokone, O. J., Monama, T. E., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Nicolson, G. D., Ockards, M. T., Oozeer, N., Passmoor, S. S., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramaila, A. J. T., Ratcliffe, S. M., Renil, R., Richter, L. L., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L. C., Schwartz, R. L., Serylak, M., Siebrits, R., Sirothia, S. K., Slabber, M. J., Smirnov, O. M., Tiplady, A. J., van Balla, T. J., van der Byl, A., Van Tonder, V., Venter, A. J., Venter, M., Welz, M. G., and Williams, L. P.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251\deg $\le l \le$ 358\deg and 2\deg $\le l \le$ 61\deg at $|b| \le 1.5\deg $). SMGPS is the largest, most sensitive and highest angular resolution 1 GHz survey of the Plane yet carried out, with an angular resolution of 8" and a broadband RMS sensitivity of $\sim$10--20 $\mu$ Jy/beam. Here we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908--1656 MHz, power law fits to the images, and broadband zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-IR classification of rare Luminous Blue Variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realisation that many of the largest radio-quiet WISE HII region candidates are not true HII regions; and a large sample of previously undiscovered background HI galaxies in the Zone of Avoidance., Comment: Accepted for publication in MNRAS. The data release is live and links can be found in the Data Availability Statement in the paper

Published
2023

2. The 1.28 GHz MeerKAT Galactic Center Mosaic

Author

Heywood, I., Rammala, I., Camilo, F., Cotton, W. D., Yusef-Zadeh, F., Abbott, T. D., Adam, R. M., Adams, G., Aldera, M. A., Asad, K. M. B., Bauermeister, E. F., Bennett, T. G. H., Bester, H. L., Bode, W. A., Botha, D. H., Botha, A. G., Brederode, L. R. S., Buchner, S., Burger, J. P., Cheetham, T., de Villiers, D. I. L., Dikgale-Mahlakoana, M. A., Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B. L., February, S., Fourie, D. J., Frank, B. S., Gamatham, R. R. G., Geyer, M., Goedhart, S., Gouws, M., Gumede, S. C., Hlakola, M. J., Hokwana, A., Hoosen, S. W., Horrell, J. M. G., Hugo, B., Isaacson, A. I., Józsa, G. I. G., Jonas, J. L., Joubert, A. F., Julie, R. P. M., Kapp, F. B., Kenyon, J. S., Kotzé, P. P. A., Kriek, N., Kriel, H., Krishnan, V. K., Lehmensiek, R., Liebenberg, D., Lord, R. T., Lunsky, B. M., Madisa, K., Magnus, L. G., Mahgoub, O., Makhaba, A., Makhathini, S., Malan, J. A., Manley, J. R., Marais, S. J., Martens, A., Mauch, T., Merry, B. C., Millenaar, R. P., Mnyandu, N., Mokone, O. J., Monama, T. E., Mphego, M. C., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Ockards, M. T., Oozeer, N., Otto, A. J., Passmoor, S. S., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramaila, A. J. T., Ramanujam, N. M. R., Ramudzuli, Z. R., Ratcliffe, S. M., Robyntjies, A., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L. C., Schwartz, R. L., Serylak, M., Siebrits, R., Sirothia, S. K., Slabber, M., Smirnov, O. M., Sofeya, L., Taljaard, B., Tasse, C., Tiplady, A. J., Toruvanda, O., Twum, S. N., van Balla, T. J., van der Byl, A., van der Merwe, C., Van Tonder, V., Van Wyk, R., Venter, A. J., Venter, M., Wallace, B. H., Welz, M. G., Williams, L. P., and Xaia, B.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

The inner $\sim$200 pc region of the Galaxy contains a 4 million M$_{\odot}$ supermassive black hole (SMBH), significant quantities of molecular gas, and star formation and cosmic ray energy densities that are roughly two orders of magnitude higher than the corresponding levels in the Galactic disk. At a distance of only 8.2 kpc, the region presents astronomers with a unique opportunity to study a diverse range of energetic astrophysical phenomena, from stellar objects in extreme environments, to the SMBH and star-formation driven feedback processes that are known to influence the evolution of galaxies as a whole. We present a new survey of the Galactic center conducted with the South African MeerKAT radio telescope. Radio imaging offers a view that is unaffected by the large quantities of dust that obscure the region at other wavelengths, and a scene of striking complexity is revealed. We produce total intensity and spectral index mosaics of the region from 20 pointings (144 hours on-target in total), covering 6.5 square degrees with an angular resolution of 4$"$,at a central frequency of 1.28 GHz. Many new features are revealed for the first time due to a combination of MeerKAT's high sensitivity, exceptional $u,v$-plane coverage, and geographical vantage point. We highlight some initial survey results, including new supernova remnant candidates, many new non-thermal filament complexes, and enhanced views of the Radio Arc Bubble, Sgr A and Sgr B regions. This project is a SARAO public legacy survey, and the image products are made available with this article., Comment: 29 pages, 15 figures, 3 tables, accepted for publication in the The Astrophysical Journal. Replacement arXiv version with higher quality figures

Published
2022
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3. The MeerKAT Galaxy Cluster Legacy Survey I. Survey Overview and Highlights

Author

Knowles, K., Cotton, W. D., Rudnick, L., Camilo, F., Goedhart, S., Deane, R., Ramatsoku, M., Bietenholz, M. F., Brüggen, M., Button, C., Chen, H., Chibueze, J. O., Clarke, T. E., de Gasperin, F., Ianjamasimanana, R., Józsa, G. I. G., Hilton, M., Kesebonye, K. C., Kolokythas, K., Kraan-Korteweg, R. C., Lawrie, G., Lochner, M., Loubser, S. I., Marchegiani, P., Mhlahlo, N., Moodley, K., Murphy, E., Namumba, B., Oozeer, N., Parekh, V., Pillay, D. S., Passmoor, S. S., Ramaila, A. J. T., Ranchod, S., Retana-Montenegro, E., Sebokolodi, L., Sikhosana, S. P., Smirnov, O., Thorat, K., Venturi, T., Abbott, T. D., Adam, R. M., Adams, G., Aldera, M. A., Bauermeister, E. F., Bennett, T. G. H., Bode, W. A., Botha, D. H., Botha, A. G., Brederode, L. R. S., Buchner, S., Burger, J. P., Cheetham, T., de Villiers, D. I. L., Dikgale-Mahlakoana, M. A., Toit, L. J. du, Esterhuyse, S. W. P., Fadana, G., Fanaroff, B. L., Fataar, S., Foley, A. R., Fourie, D. J., Frank, B. S., Gamatham, R. R. G., Gatsi, T. G., Geyer, M., Gouws, M., Gumede, S. C., Heywood, I., Hlakola, M. J., Hokwana, A., Hoosen, S. W., Horn, D. M., Horrell, J. M. G., Hugo, B. V., Isaacson, A. R., Jonas, J. L., Jordaan, J. D. B., Joubert, A. F., Julie, R. P. M., Kapp, F. B., Kasper, V. A., Kenyon, J. S., Kotzé, P. P. A., Kotze, A. G., Kriek, N., Kriel, H., Krishnan, V. K., Kusel, T. W., Legodi, L. S., Lehmensiek, R., Liebenberg, D., Lord, R. T., Lunsky, B. M., Madisa, K., Magnus, L. G., Main, J. P. L., Makhaba, A., Makhathini, S., Malan, J. A., Manley, J. R., Marais, S. J., Maree, M. D. J., Martens, A., Mauch, T., McAlpine, K., Merry, B. C., Millenaar, R. P., Mokone, O. J., Monama, T. E., Mphego, M. C., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Ockards, M. T., Otto, A. J., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramanujam, N. M., Ramudzuli, Z. R., Ratcliffe, S. M., Renil, R., Robyntjies, A., Rust, A. N., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L. C., Schwartz, R. L., Serylak, M., Siebrits, R., Sirothia, S. K., Slabber, M., Sofeya, L., Taljaard, B., Tasse, C., Tiplady, A. J., Toruvanda, O., Twum, S. N., van Balla, T. J., van der Byl, A., van der Merwe, C., van Dyk, C. L., Van Tonder, V., Van Wyk, R., Venter, A. J., Venter, M., Welz, M. G., Williams, L. P., and Xaia, B.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

MeerKAT's large number of antennas, spanning 8 km with a densely packed 1 km core, create a powerful instrument for wide-area surveys, with high sensitivity over a wide range of angular scales. The MeerKAT Galaxy Cluster Legacy Survey (MGCLS) is a programme of long-track MeerKAT L-band (900-1670 MHz) observations of 115 galaxy clusters, observed for $\sim$6-10 hours each in full polarisation. The first legacy product data release (DR1), made available with this paper, includes the MeerKAT visibilities, basic image cubes at $\sim$8" resolution, and enhanced spectral and polarisation image cubes at $\sim$8" and 15" resolutions. Typical sensitivities for the full-resolution MGCLS image products are $\sim$3-5 {\mu}Jy/beam. The basic cubes are full-field and span 4 deg^2. The enhanced products consist of the inner 1.44 deg^2 field of view, corrected for the primary beam. The survey is fully sensitive to structures up to $\sim$10' scales and the wide bandwidth allows spectral and Faraday rotation mapping. HI mapping at 209 kHz resolution can be done at $0

Published
2021
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4. The MeerKAT Telescope as a Pulsar Facility: System verification and early science results from MeerTime

Author

Bailes, M., Jameson, A., Abbate, F., Barr, E. D., Bhat, N. D. R., Bondonneau, L., Burgay, M., Buchner, S. J., Camilo, F., Champion, D. J., Cognard, I., Demorest, P. B., Freire, P. C. C., Gautam, T., Geyer, M., Griessmeier, J. M., Guillemot, L., Hu, H., Jankowski, F., Johnston, S., Karastergiou, A., Karuppusamy, R., Kaur, D., Keith, M. J., Kramer, M., van Leeuwen, J., Lower, M. E., Maan, Y., McLaughlin, M. A., Meyers, B. W., Osłowski, S., Oswald, L. S., Parthasarathy, A., Pennucci, T., Posselt, B., Possenti, A., Ransom, S. M., Reardon, D. J., Ridolfi, A., Schollar, C. T. G., Serylak, M., Shaifullah, G., Shamohammadi, M., Shannon, R. M., Sobey, C., Song, X., Spiewak, R., Stairs, I. H., Stappers, B. W., van Straten, W., Szary, A., Theureau, G., Krishnan, V. Venkatraman, Weltevrede, P., Wex, N., Abbott, T. D., Adams, G. B., Burger, J. P., Gamatham, R. R. G., Gouws, M., Horn, D. M., Hugo, B., Joubert, A. F., Manley, J. R., McAlpine, K., Passmoor, S. S., Peens-Hough, A., Ramudzuli, Z. R., Rust, A., Salie, S., Schwardt, L. C., Siebrits, R., Van Tonder, G., Van Tonder, V., and Welz, M. G.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract

We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for the newly-commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. MeerKAT is a high-gain (~2.8 K/Jy) low-system temperature (~18 K at 20cm) radio array that currently operates from 580-1670 MHz and can produce tied-array beams suitable for pulsar observations. This paper presents results from the MeerTime Large Survey Project and commissioning tests with PTUSE. Highlights include observations of the double pulsar J0737-3039A, pulse profiles from 34 millisecond pulsars from a single 2.5h observation of the Globular cluster Terzan 5, the rotation measure of Ter5O, a 420-sigma giant pulse from the Large Magellanic Cloud pulsar PSR J0540-6919, and nulling identified in the slow pulsar PSR J0633-2015. One of the key design specifications for MeerKAT was absolute timing errors of less than 5 ns using their novel precise time system. Our timing of two bright millisecond pulsars confirm that MeerKAT delivers exceptional timing. PSR J2241-5236 exhibits a jitter limit of <4 ns per hour whilst timing of PSR J1909-3744 over almost 11 months yields an rms residual of 66 ns with only 4 min integrations. Our results confirm that the MeerKAT is an exceptional pulsar telescope. The array can be split into four separate sub-arrays to time over 1000 pulsars per day and the future deployment of S-band (1750-3500 MHz) receivers will further enhance its capabilities., Comment: 20 pages, 16 Figures, 4 Tables, accepted for publication in PASA

Published
2020
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5. The 1.28 GHz MeerKAT DEEP2 Image

Author

Mauch, T., Cotton, W. D., Condon, J. J., Matthews, A. M., Abbott, T. D., Adam, R. M., Aldera, M. A., Asad, K. M. B., Bauermeister, E. F., Bennett, T. G. H., Bester, H., Botha, D. H., Brederode, L. R. S., Brits, Z. B., Buchner, S. J., Burger, J. P., Camilo, F., Chalmers, J. M., Cheetham, T., de Villiers, D., de Villiers, M. S., Dikgale-Mahlakoana, M. A., Toit, L. J. du, Esterhuyse, S. W. P., Fadana, G., Fanaroff, B. L., Fataar, S., February, S., Frank, B. S., Gamatham, R. R. G., Geyer, M., Goedhart, S., Gounden, S., Gumede, S. C., Heywood, I., Hlakola, M. J., Horrell, J. M. G., Hugo, B., Isaacson, A. R., Józsa, G. I. G., Jonas, J. L., Julie, R. P. M., Kapp, F. B., Kasper, V. A., Kenyon, J. S., Kotzé, P. P. A., Kriek, N., Kriel, H., Kusel, T. W., Lehmensiek, R., Loots, A., Lord, R. T., Lunsky, B. M., Madisa, K., Magnus, L. G., Main, J. P. L., Malan, J. A., Manley, J. R., Marais, S. J., Martens, A., Merry, B., Millenaar, R., Mnyandu, N., Moeng, I. P. T., Mokone, O. J., Monama, T. E., Mphego, M. C., New, W. S., Ngcebetsha, B., Ngoasheng, K. J., Ockards, M. T. O., Oozeer, N., Otto, A. J., Patel, A. A., Peens-Hough, A., Perkins, S. J., Ramaila, A. J. T., Ramudzuli, Z. R., Renil, R., Richter, L. L., Robyntjies, A., Salie, S., Schollar, C. T. G., Schwardt, L. C., Serylak, M., Siebrits, R., Sirothia, S. K., Smirnov, O. M., Sofeya, L., Stone, G., Taljaard, B., Tasse, C., Theron, I. P., Tiplady, A. J., Toruvanda, O., Twum, S. N., van Balla, T. J., van der Byl, A., van der Merwe, C., Van Tonder, V., Wallace, B. H., Welz, M. G., Williams, L. P., and Xaia, B.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the confusion-limited 1.28 GHz MeerKAT DEEP2 image covering one $\approx 68'$ FWHM primary beam area with $7.6''$ FWHM resolution and $0.55 \pm 0.01$ $\mu$Jy/beam rms noise. Its J2000 center position $\alpha=04^h 13^m 26.4^s$, $\delta=-80^\circ 00' 00''$ was selected to minimize artifacts caused by bright sources. We introduce the new 64-element MeerKAT array and describe commissioning observations to measure the primary beam attenuation pattern, estimate telescope pointing errors, and pinpoint $(u,v)$ coordinate errors caused by offsets in frequency or time. We constructed a 1.4 GHz differential source count by combining a power-law count fit to the DEEP2 confusion $P(D)$ distribution from $0.25$ to $10$ $\mu$Jy with counts of individual DEEP2 sources between $10$ $\mu$Jy and $2.5$ mJy. Most sources fainter than $S \sim 100$ $\mu$Jy are distant star-forming galaxies obeying the FIR/radio correlation, and sources stronger than $0.25$ $\mu$Jy account for $\sim93\%$ of the radio background produced by star-forming galaxies. For the first time, the DEEP2 source count has reached the depth needed to reveal the majority of the star formation history of the universe. A pure luminosity evolution of the 1.4 GHz local luminosity function consistent with the Madau & Dickinson (2014) model for the evolution of star-forming galaxies based on UV and infrared data underpredicts our 1.4 GHz source count in the range $-5 \lesssim \log[S(\mathrm{Jy})] \lesssim -4$., Comment: 20 pages, 18 figures. Accepted for publication in ApJ

Published
2019
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6. Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event

Author

Heywood, I., Camilo, F., Cotton, W. D., Yusef-Zadeh, F., Abbott, T. D., Adam, R. M., Aldera, M. A., Bauermeister, E. F., Booth, R. S., Botha, A. G., Botha, D. H., Brederode, L. R. S., Brits, Z. B., Buchner, S. J., Burger, J. P., Chalmers, J. M., Cheetham, T., de Villiers, D., Dikgale-Mahlakoana, M. A., Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B. L., Foley, A. R., Fourie, D. J., Gamatham, R. R. G., Goedhart, S., Gounden, S., Hlakola, M. J., Hoek, C. J., Hokwana, A., Horn, D. M., Horrell, J. M. G., Hugo, B., Isaacson, A. R., Jonas, J. L., Jordaan, J. D. B. L., Joubert, A. F., Józsa, G. I. G., Julie, R. P. M., Kapp, F. B., Kenyon, J. S., Kotzé, P. P. A., Kriel, H., Kusel, T. W., Lehmensiek, R., Liebenberg, D., Loots, A., Lord, R. T., Lunsky, B. M., Macfarlane, P. S., Magnus, L. G., Magozore, C. M., Mahgoub, O., Main, J. P. L., Malan, J. A., Malgas, R. D., Manley, J. R., Maree, M. D. J., Merry, B., Millenaar, R., Mnyandu, N., Moeng, I. P. T., Monama, T. E., Mphego, M. C., New, W. S., Ngcebetsha, B., Oozeer, N., Otto, A. J., Passmoor, S. S., Pate, A. A., Peens-Hough, A., Perkins, S. J., Ratcliffe, S. M., Renil, R., Rust, A., Salie, S., Schwardt, L. C., Serylak, M., Siebrits, R., Sirothia, S. K., Smirnov, O. M., Sofeya, L., Swart, P. S., Tasse, C., Taylor, D. T., Theron, I. P., Thorat, K., Tiplad, A. J., Tshongweni, S., van Balla, T. J., van der Byl, A., van der Merwe, C., van Dyk, C. L., Van Rooyen, R., Van Tonder, V., Van Wyk, R., Wallace, B. H., Welz, M. G., and Williams, L. P.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

The Galactic Centre contains a supermassive black hole with a mass of 4 million suns within an environment that differs markedly from that of the Galactic disk. While the black hole is essentially quiescent in the broader context of active galactic nuclei, X-ray observations have provided evidence for energetic outbursts from its surroundings. Also, while the levels of star formation in the Galactic Centre have been approximately constant over the last few hundred Myr, there is evidence of elevated short-duration bursts, strongly influenced by interaction of the black hole with the enhanced gas density present within the ring-like Central Molecular Zone at Galactic longitude |l| < 0.7 degrees and latitude |b| < 0.2 degrees. The inner 200 pc region is characterized by large amounts of warm molecular gas, a high cosmic ray ionization rate, unusual gas chemistry, enhanced synchrotron emission, and a multitude of radio-emitting magnetised filaments, the origin of which has not been established. Here we report radio imaging that reveals bipolar bubbles spanning 1 degree x 3 degrees (140 parsecs x 430 parsecs), extending above and below the Galactic plane and apparently associated with the Galactic Centre. The structure is edge-brightened and bounded, with symmetry implying creation by an energetic event in the Galactic Centre. We estimate the age of the bubbles to be a few million years, with a total energy of 7 x 10^52 ergs. We postulate that the progenitor event was a major contributor to the increased cosmic-ray density in the Galactic Centre, and is in turn the principal source of the relativistic particles required to power the synchrotron emission of the radio filaments within and in the vicinity of the bubble cavities., Comment: 25 pages, 3 figures, 3 tables, authors' version of a Letter published in Nature on 11 September 2019

Published
2019
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7. Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

Author

Camilo, F., Scholz, P., Serylak, M., Buchner, S., Merryfield, M., Kaspi, V. M., Archibald, R. F., Bailes, M., Jameson, A., van Straten, W., Sarkissian, J., Reynolds, J. E., Johnston, S., Hobbs, G., Abbott, T. D., Adam, R. M., Adams, G. B., Alberts, T., Andreas, R., Asad, K. M. B., Baker, D. E., Baloyi, T., Bauermeister, E. F., Baxana, T., Bennett, T. G. H., Bernardi, G., Booisen, D., Booth, R. S., Botha, D. H., Boyana, L., Brederode, L. R. S., Burger, J. P., Cheetham, T., Conradie, J., Conradie, J. P., Davidson, D. B., de Bruin, G., de Swardt, B., de Villiers, C., de Villiers, D. I. L., de Villiers, M. S., de Villiers, W., de Waal, C., Dikgale, M. A., Toit, G. du, Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B., Fataar, S., Foley, A. R., Foster, G., Fourie, D., Gamatham, R., Gatsi, T., Geschke, R., Goedhart, S., Grobler, T. L., Gumede, S. C., Hlakola, M. J., Hokwana, A., Hoorn, D. H., Horn, D., Horrell, J., Hugo, B., Isaacson, A., Jacobs, O., van Rensburg, J. P. Jansen, Jonas, J. L., Jordaan, B., Joubert, A., Joubert, F., Jozsa, G. I. G., Julie, R., Julius, C. C., Kapp, F., Karastergiou, A., Karels, F., Kariseb, M., Karuppusamy, R., Kasper, V., Knox-Davies, E. C., Koch, D., Kotze, P. P. A., Krebs, A., Kriek, N., Kriel, H., Kusel, T., Lamoor, S., Lehmensiek, R., Liebenberg, D., Liebenberg, I., Lord, R. T., Lunsky, B., Mabombo, N., Macdonald, T., Macfarlane, P., Madisa, K., Mafhungo, L., Magnus, L. G., Magozore, C., Mahgoub, O., Main, J. P. L., Makhathini, S., Malan, J. A., Malgas, P., Manley, J. R., Manzini, M., Marais, L., Marais, N., Marais, S. J., Maree, M., Martens, A., Matshawule, S. D., Matthysen, N., Mauch, T., Nally, L. D. Mc, Merry, B., Millenaar, R. P., Mjikelo, C., Mkhabela, N., Mnyandu, N., Moeng, I. T., Mokone, O. J., Monama, T. E., Montshiwa, K., Moss, V., Mphego, M., New, W., Ngcebetsha, B., Ngoasheng, K., Niehaus, H., Ntuli, P., Nzama, A., Obies, F., Obrocka, M., Ockards, M. T., Olyn, C., Oozeer, N., Otto, A. J., Padayachee, Y., Passmoor, S., Patel, A. A., Paula, S., Peens-Hough, A., Pholoholo, B., Prozesky, P., Rakoma, S., Ramaila, A. J. T., Rammala, I., Ramudzuli, Z. R., Rasivhaga, M., Ratcliffe, S., Reader, H. C., Renil, R., Richter, L., Robyntjies, A., Rosekrans, D., Rust, A., Salie, S., Sambu, N., Schollar, C. T. G., Schwardt, L., Seranyane, S., Sethosa, G., Sharpe, C., Siebrits, R., Sirothia, S. K., Slabber, M. J., Smirnov, O., Smith, S., Sofeya, L., Songqumase, N., Spann, R., Stappers, B., Steyn, D., Steyn, T. J., Strong, R., Struthers, A., Stuart, C., Sunnylall, P., Swart, P. S., Taljaard, B., Tasse, C., Taylor, G., Theron, I. P., Thondikulam, V., Thorat, K., Tiplady, A., Toruvanda, O., van Aardt, J., van Balla, T., Heever, L. van den, van der Byl, A., van der Merwe, C., van der Merwe, P., van Niekerk, P. C., van Rooyen, R., van Staden, J. P., van Tonder, V., van Wyk, R., Wait, I., Walker, A. L., Wallace, B., Welz, M., Williams, L. P., Xaia, B., Young, N., and Zitha, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100x larger than during its dormant state. The X-ray flux one month after reactivation was at least 800x larger than during quiescence, and has been decaying exponentially on a 111+/-19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6-8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation., Comment: Published in ApJ (2018 April 5); 13 pages, 4 figures

Published
2018
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8. Engineering and Science Highlights of the KAT-7 Radio Telescope

Author

Foley, A. R., Alberts, T., Armstrong, R P., Barta, A., Bauermeister, E. F., Bester, H., Blose, S., Booth, R. S., Botha, D. H., Buchner, S. J., Carignan, C., Cheetham, T., Cloete, K., Coreejes, G., Crida, R. C., Cross, S. D., Curtolo, F., Dikgale, A., de Villiers, M. S., Toit, L. J. du, Esterhuyse, S. W. P., Fanaroff, B., Fender, R. P., Fijalkowski, M., Fourie, D., Frank, B., George, D., Gibbs, P., Goedhart, S., Grobbelaar, J., Gumede, S. C., Herselman, P., Hess, K. M., Hoek, N., Horrell, J., Jonas, J. L., Jordaan, J. D. B., Julie, R., Kapp, F., Kotzé, P., Kusel, T., Langman, A., Lehmensiek, R., Liebenberg, D., Liebenberg, I. J. V., Loots, A., Lord, R. T., Lucero, D. M., Ludick, J., Macfarlane, P., Madlavana, M., Magnus, L., Magozore, C., Malan, J. A., Manley, J. R., Marais, L., Marais, N., Marais, S. J., Maree, M., Martens, A., Mokone, O., Moss, V., Mthembu, S., New, W., Nicholson, G. D., van Niekerk, P. C., Oozeer, N., Passmoor, S. S., Peens-Hough, A., Pińska, A. B., Prozesky, P., Rajan, S., Ratcliffe, S., Renil, R., Richter, L. L., Rosekrans, D., Rust, A., Schröder, A. C., Schwardt, L. C., Seranyane, S., Serylak, M., Shepherd, D. S., Siebrits, R., Sofeya, L., Spann, R., Springbok, R., Swart, P. S., Thondikulam, Venkatasubramani L., Theron, I. P., Tiplady, A., Toruvanda, O., Tshongweni, S., Heever, L. van den, van der Merwe, C., van Rooyen, R., Wakhaba, S., Walker, A. L., Welz, M., Williams, L., Wolleben, M., Woudt, P. A., Young, N. J., and Zwart, J. T. L.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The construction of the KAT-7 array in the Karoo region of the Northern Cape in South Africa was intended primarily as an engineering prototype for technologies and techniques applicable to the MeerKAT telescope. This paper looks at the main engineering and scien- tific highlights from this effort, and discusses their applicability to both MeerKAT and other next-generation radio telescopes. In particular we found that the composite dish surface works well, but it becomes complicated to fabricate for a dish lacking circular symmetry; the Stir- ling cycle cryogenic system with ion pump to achieve vacuum works but demands much higher maintenance than an equivalent Gifford-McMahon cycle system; the ROACH (Recon- figurable Open Architecture Computing Hardware)-based correlator with SPEAD (Stream- ing Protocol for Exchanging Astronomical Data) protocol data transfer works very well and KATCP (Karoo Array Telescope Control Protocol) control protocol has proven very flexible and convenient. KAT-7 has also been used for scientific observations where it has a niche in mapping low surface-brightness continuum sources, some extended HI halos and OH masers in star-forming regions. It can also be used to monitor continuum source variability, observe pulsars, and make VLBI observations

Published
2016
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10. The MeerKAT Telescope as a Pulsar Facility: System verification and early science results from MeerTime

Author

Bailes, M, Jameson, A, Abbate, F, Barr, E, Bhat, N, Bondonneau, L, Burgay, M, Buchner, S, Camilo, F, Champion, D, Cognard, I, Demorest, P, Freire, P, Gautam, T, Geyer, M, Griessmeier, J, Guillemot, L, Hu, H, Jankowski, F, Johnston, S, Karastergiou, A, Karuppusamy, R, Kaur, D, Keith, M, Kramer, M, van Leeuwen, J, Lower, M, Maan, Y, Mclaughlin, M, Meyers, B, Osłowski, S, Oswald, L, Parthasarathy, A, Pennucci, T, Posselt, B, Possenti, A, Ransom, S, Reardon, D, Ridolfi, A, Schollar, C, Serylak, M, Shaifullah, G, Shamohammadi, M, Shannon, R, Sobey, C, Song, X, Spiewak, R, Stairs, I, Stappers, B, van Straten, W, Szary, A, Theureau, G, Venkatraman Krishnan, V, Weltevrede, P, Wex, N, Abbott, T, Adams, G, Burger, J, Gamatham, R, Gouws, M, Horn, D, Hugo, B, Joubert, A, Manley, J, Mcalpine, K, Passmoor, S, Peens-Hough, A, Ramudzuli, Z, Rust, A, Salie, S, Schwardt, L, Siebrits, R, Van Tonder, G, Van Tonder, V, Welz, M, Bailes, M., Jameson, A., Abbate, F., Barr, E. D., Bhat, N. D. R., Bondonneau, L., Burgay, M., Buchner, S. J., Camilo, F., Champion, D. J., Cognard, I., Demorest, P. B., Freire, P. C. C., Gautam, T., Geyer, M., Griessmeier, J. M., Guillemot, L., Hu, H., Jankowski, F., Johnston, S., Karastergiou, A., Karuppusamy, R., Kaur, D., Keith, M. J., Kramer, M., van Leeuwen, J., Lower, M. E., Maan, Y., McLaughlin, M. A., Meyers, B. W., Osłowski, S., Oswald, L. S., Parthasarathy, A., Pennucci, T., Posselt, B., Possenti, A., Ransom, S. M., Reardon, D. J., Ridolfi, A., Schollar, C. T. G., Serylak, M., Shaifullah, G., Shamohammadi, M., Shannon, R. M., Sobey, C., Song, X., Spiewak, R., Stairs, I. H., Stappers, B. W., van Straten, W., Szary, A., Theureau, G., Venkatraman Krishnan, V., Weltevrede, P., Wex, N., Abbott, T. D., Adams, G. B., Burger, J. P., Gamatham, R. R. G., Gouws, M., Horn, D. M., Hugo, B., Joubert, A. F., Manley, J. R., McAlpine, K., Passmoor, S. S., Peens-Hough, A., Ramudzuli, Z. R., Rust, A., Salie, S., Schwardt, L. C., Siebrits, R., Van Tonder, G., Van Tonder, V., Welz, M. G., Bailes, M, Jameson, A, Abbate, F, Barr, E, Bhat, N, Bondonneau, L, Burgay, M, Buchner, S, Camilo, F, Champion, D, Cognard, I, Demorest, P, Freire, P, Gautam, T, Geyer, M, Griessmeier, J, Guillemot, L, Hu, H, Jankowski, F, Johnston, S, Karastergiou, A, Karuppusamy, R, Kaur, D, Keith, M, Kramer, M, van Leeuwen, J, Lower, M, Maan, Y, Mclaughlin, M, Meyers, B, Osłowski, S, Oswald, L, Parthasarathy, A, Pennucci, T, Posselt, B, Possenti, A, Ransom, S, Reardon, D, Ridolfi, A, Schollar, C, Serylak, M, Shaifullah, G, Shamohammadi, M, Shannon, R, Sobey, C, Song, X, Spiewak, R, Stairs, I, Stappers, B, van Straten, W, Szary, A, Theureau, G, Venkatraman Krishnan, V, Weltevrede, P, Wex, N, Abbott, T, Adams, G, Burger, J, Gamatham, R, Gouws, M, Horn, D, Hugo, B, Joubert, A, Manley, J, Mcalpine, K, Passmoor, S, Peens-Hough, A, Ramudzuli, Z, Rust, A, Salie, S, Schwardt, L, Siebrits, R, Van Tonder, G, Van Tonder, V, Welz, M, Bailes, M., Jameson, A., Abbate, F., Barr, E. D., Bhat, N. D. R., Bondonneau, L., Burgay, M., Buchner, S. J., Camilo, F., Champion, D. J., Cognard, I., Demorest, P. B., Freire, P. C. C., Gautam, T., Geyer, M., Griessmeier, J. M., Guillemot, L., Hu, H., Jankowski, F., Johnston, S., Karastergiou, A., Karuppusamy, R., Kaur, D., Keith, M. J., Kramer, M., van Leeuwen, J., Lower, M. E., Maan, Y., McLaughlin, M. A., Meyers, B. W., Osłowski, S., Oswald, L. S., Parthasarathy, A., Pennucci, T., Posselt, B., Possenti, A., Ransom, S. M., Reardon, D. J., Ridolfi, A., Schollar, C. T. G., Serylak, M., Shaifullah, G., Shamohammadi, M., Shannon, R. M., Sobey, C., Song, X., Spiewak, R., Stairs, I. H., Stappers, B. W., van Straten, W., Szary, A., Theureau, G., Venkatraman Krishnan, V., Weltevrede, P., Wex, N., Abbott, T. D., Adams, G. B., Burger, J. P., Gamatham, R. R. G., Gouws, M., Horn, D. M., Hugo, B., Joubert, A. F., Manley, J. R., McAlpine, K., Passmoor, S. S., Peens-Hough, A., Ramudzuli, Z. R., Rust, A., Salie, S., Schwardt, L. C., Siebrits, R., Van Tonder, G., Van Tonder, V., and Welz, M. G.

Abstract

We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for the newly commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. MeerKAT is a high-gain low-system temperature radio array that currently operates at 580-1 670 MHz and can produce tied-array beams suitable for pulsar observations. This paper presents results from the MeerTime Large Survey Project and commissioning tests with PTUSE. Highlights include observations of the double pulsar, pulse profiles from 34 millisecond pulsars (MSPs) from a single 2.5-h observation of the Globular cluster Terzan 5, the rotation measure of Ter5O, a 420-sigma giant pulse from the Large Magellanic Cloud pulsar PSR , and nulling identified in the slow pulsar PSR J0633-2015. One of the key design specifications for MeerKAT was absolute timing errors of less than 5 ns using their novel precise time system. Our timing of two bright MSPs confirm that MeerKAT delivers exceptional timing. PSR exhibits a jitter limit of whilst timing of PSR over almost 11 months yields an rms residual of 66 ns with only 4 min integrations. Our results confirm that the MeerKAT is an exceptional pulsar telescope. The array can be split into four separate sub-arrays to time over 1 000 pulsars per day and the future deployment of S-band (1 750-3 500 MHz) receivers will further enhance its capabilities.

Published
2020

11. The 1.28 GHz MeerKAT Galactic Center Mosaic

Author

Heywood, I., primary, Rammala, I., additional, Camilo, F., additional, Cotton, W. D., additional, Yusef-Zadeh, F., additional, Abbott, T. D., additional, Adam, R. M., additional, Adams, G., additional, Aldera, M. A., additional, Asad, K. M. B., additional, Bauermeister, E. F., additional, Bennett, T. G. H., additional, Bester, H. L., additional, Bode, W. A., additional, Botha, D. H., additional, Botha, A. G., additional, Brederode, L. R. S., additional, Buchner, S., additional, Burger, J. P., additional, Cheetham, T., additional, de Villiers, D. I. L., additional, Dikgale-Mahlakoana, M. A., additional, du Toit, L. J., additional, Esterhuyse, S. W. P., additional, Fanaroff, B. L., additional, February, S., additional, Fourie, D. J., additional, Frank, B. S., additional, Gamatham, R. R. G., additional, Geyer, M., additional, Goedhart, S., additional, Gouws, M., additional, Gumede, S. C., additional, Hlakola, M. J., additional, Hokwana, A., additional, Hoosen, S. W., additional, Horrell, J. M. G., additional, Hugo, B., additional, Isaacson, A. I., additional, Józsa, G. I. G., additional, Jonas, J. L., additional, Joubert, A. F., additional, Julie, R. P. M., additional, Kapp, F. B., additional, Kenyon, J. S., additional, Kotzé, P. P. A., additional, Kriek, N., additional, Kriel, H., additional, Krishnan, V. K., additional, Lehmensiek, R., additional, Liebenberg, D., additional, Lord, R. T., additional, Lunsky, B. M., additional, Madisa, K., additional, Magnus, L. G., additional, Mahgoub, O., additional, Makhaba, A., additional, Makhathini, S., additional, Malan, J. A., additional, Manley, J. R., additional, Marais, S. J., additional, Martens, A., additional, Mauch, T., additional, Merry, B. C., additional, Millenaar, R. P., additional, Mnyandu, N., additional, Mokone, O. J., additional, Monama, T. E., additional, Mphego, M. C., additional, New, W. S., additional, Ngcebetsha, B., additional, Ngoasheng, K. J., additional, Ockards, M. T., additional, Oozeer, N., additional, Otto, A. J., additional, Passmoor, S. S., additional, Patel, A. A., additional, Peens-Hough, A., additional, Perkins, S. J., additional, Ramaila, A. J. T., additional, Ramanujam, N. M. R., additional, Ramudzuli, Z. R., additional, Ratcliffe, S. M., additional, Robyntjies, A., additional, Salie, S., additional, Sambu, N., additional, Schollar, C. T. G., additional, Schwardt, L. C., additional, Schwartz, R. L., additional, Serylak, M., additional, Siebrits, R., additional, Sirothia, S. K., additional, Slabber, M., additional, Smirnov, O. M., additional, Sofeya, L., additional, Taljaard, B., additional, Tasse, C., additional, Tiplady, A. J., additional, Toruvanda, O., additional, Twum, S. N., additional, van Balla, T. J., additional, van der Byl, A., additional, van der Merwe, C., additional, Van Tonder, V., additional, Van Wyk, R., additional, Venter, A. J., additional, Venter, M., additional, Wallace, B. H., additional, Welz, M. G., additional, Williams, L. P., additional, and Xaia, B., additional

Published
2022
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12. The MeerKAT Galaxy Cluster Legacy Survey

Author

Knowles, K., primary, Cotton, W. D., additional, Rudnick, L., additional, Camilo, F., additional, Goedhart, S., additional, Deane, R., additional, Ramatsoku, M., additional, Bietenholz, M. F., additional, Brüggen, M., additional, Button, C., additional, Chen, H., additional, Chibueze, J. O., additional, Clarke, T. E., additional, de Gasperin, F., additional, Ianjamasimanana, R., additional, Józsa, G. I. G., additional, Hilton, M., additional, Kesebonye, K. C., additional, Kolokythas, K., additional, Kraan-Korteweg, R. C., additional, Lawrie, G., additional, Lochner, M., additional, Loubser, S. I., additional, Marchegiani, P., additional, Mhlahlo, N., additional, Moodley, K., additional, Murphy, E., additional, Namumba, B., additional, Oozeer, N., additional, Parekh, V., additional, Pillay, D. S., additional, Passmoor, S. S., additional, Ramaila, A. J. T., additional, Ranchod, S., additional, Retana-Montenegro, E., additional, Sebokolodi, L., additional, Sikhosana, S. P., additional, Smirnov, O., additional, Thorat, K., additional, Venturi, T., additional, Abbott, T. D., additional, Adam, R. M., additional, Adams, G., additional, Aldera, M. A., additional, Bauermeister, E. F., additional, Bennett, T. G. H., additional, Bode, W. A., additional, Botha, D. H., additional, Botha, A. G., additional, Brederode, L. R. S., additional, Buchner, S., additional, Burger, J. P., additional, Cheetham, T., additional, de Villiers, D. I. L., additional, Dikgale-Mahlakoana, M. A., additional, du Toit, L. J., additional, Esterhuyse, S. W. P., additional, Fadana, G., additional, Fanaroff, B. L., additional, Fataar, S., additional, Foley, A. R., additional, Fourie, D. J., additional, Frank, B. S., additional, Gamatham, R. R. G., additional, Gatsi, T. G., additional, Geyer, M., additional, Gouws, M., additional, Gumede, S. C., additional, Heywood, I., additional, Hlakola, M. J., additional, Hokwana, A., additional, Hoosen, S. W., additional, Horn, D. M., additional, Horrell, J. M. G., additional, Hugo, B. V., additional, Isaacson, A. R., additional, Jonas, J. L., additional, Jordaan, J. D. B., additional, Joubert, A. F., additional, Julie, R. P. M., additional, Kapp, F. B., additional, Kasper, V. A., additional, Kenyon, J. S., additional, Kotzé, P. P. A., additional, Kotze, A. G., additional, Kriek, N., additional, Kriel, H., additional, Krishnan, V. K., additional, Kusel, T. W., additional, Legodi, L. S., additional, Lehmensiek, R., additional, Liebenberg, D., additional, Lord, R. T., additional, Lunsky, B. M., additional, Madisa, K., additional, Magnus, L. G., additional, Main, J. P. L., additional, Makhaba, A., additional, Makhathini, S., additional, Malan, J. A., additional, Manley, J. R., additional, Marais, S. J., additional, Maree, M. D. J., additional, Martens, A., additional, Mauch, T., additional, McAlpine, K., additional, Merry, B. C., additional, Millenaar, R. P., additional, Mokone, O. J., additional, Monama, T. E., additional, Mphego, M. C., additional, New, W. S., additional, Ngcebetsha, B., additional, Ngoasheng, K. J., additional, Ockards, M. T., additional, Otto, A. J., additional, Patel, A. A., additional, Peens-Hough, A., additional, Perkins, S. J., additional, Ramanujam, N. M., additional, Ramudzuli, Z. R., additional, Ratcliffe, S. M., additional, Renil, R., additional, Robyntjies, A., additional, Rust, A. N., additional, Salie, S., additional, Sambu, N., additional, Schollar, C. T. G., additional, Schwardt, L. C., additional, Schwartz, R. L., additional, Serylak, M., additional, Siebrits, R., additional, Sirothia, S. K., additional, Slabber, M., additional, Sofeya, L., additional, Taljaard, B., additional, Tasse, C., additional, Tiplady, A. J., additional, Toruvanda, O., additional, Twum, S. N., additional, van Balla, T. J., additional, van der Byl, A., additional, van der Merwe, C., additional, van Dyk, C. L., additional, Van Tonder, V., additional, Van Wyk, R., additional, Venter, A. J., additional, Venter, M., additional, Welz, M. G., additional, Williams, L. P., additional, and Xaia, B., additional

Published
2022
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14. Does More Expert Adjustment Associate with Less Accurate Professional Forecasts?

Author

Franses, Ph.H.B.F. (Philip Hans), Welz, M. (Max), Franses, Ph.H.B.F. (Philip Hans), and Welz, M. (Max)

Abstract

Professional forecasters can rely on an econometric model to create their forecasts. It is usually unknown to what extent they adjust an econometric model‐based forecast. In this paper we show, while making just two simple assumptions, that it is possible to estimate the persistence and variance of the deviation of their forecasts from forecasts from an econometric model. A key feature of the data that facilitates our estimates is that we have forecast updates for the same forecast target. An illustration to consensus forecasters who give forecasts for GDP growth, inflation and unemployment for a range of countries and years suggests that the more a forecaster deviates from a prediction from an econometric model, the less accurate are the forecasts.

Published
2020
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17. The 1.28 GHz MeerKAT DEEP2 Image

Author

Mauch, T., primary, Cotton, W. D., additional, Condon, J. J., additional, Matthews, A. M., additional, Abbott, T. D., additional, Adam, R. M., additional, Aldera, M. A., additional, Asad, K. M. B., additional, Bauermeister, E. F., additional, Bennett, T. G. H., additional, Bester, H., additional, Botha, D. H., additional, Brederode, L. R. S., additional, Brits, Z. B., additional, Buchner, S. J., additional, Burger, J. P., additional, Camilo, F., additional, Chalmers, J. M., additional, Cheetham, T., additional, Villiers, D. de, additional, Villiers, M. S. de, additional, Dikgale-Mahlakoana, M. A., additional, Toit, L. J. du, additional, Esterhuyse, S. W. P., additional, Fadana, G., additional, Fanaroff, B. L., additional, Fataar, S., additional, February, S., additional, Frank, B. S., additional, Gamatham, R. R. G., additional, Geyer, M., additional, Goedhart, S., additional, Gounden, S., additional, Gumede, S. C., additional, Heywood, I., additional, Hlakola, M. J., additional, Horrell, J. M. G., additional, Hugo, B., additional, Isaacson, A. R., additional, Józsa, G. I. G., additional, Jonas, J. L., additional, Julie, R. P. M., additional, Kapp, F. B., additional, Kasper, V. A., additional, Kenyon, J. S., additional, Kotzé, P. P. A., additional, Kriek, N., additional, Kriel, H., additional, Kusel, T. W., additional, Lehmensiek, R., additional, Loots, A., additional, Lord, R. T., additional, Lunsky, B. M., additional, Madisa, K., additional, Magnus, L. G., additional, Main, J. P. L., additional, Malan, J. A., additional, Manley, J. R., additional, Marais, S. J., additional, Martens, A., additional, Merry, B., additional, Millenaar, R., additional, Mnyandu, N., additional, Moeng, I. P. T., additional, Mokone, O. J., additional, Monama, T. E., additional, Mphego, M. C., additional, New, W. S., additional, Ngcebetsha, B., additional, Ngoasheng, K. J., additional, Ockards, M. T. O., additional, Oozeer, N., additional, Otto, A. J., additional, Patel, A. A., additional, Peens-Hough, A., additional, Perkins, S. J., additional, Ramaila, A. J. T., additional, Ramudzuli, Z. R., additional, Renil, R., additional, Richter, L. L., additional, Robyntjies, A., additional, Salie, S., additional, Schollar, C. T. G., additional, Schwardt, L. C., additional, Serylak, M., additional, Siebrits, R., additional, Sirothia, S. K., additional, Smirnov, O. M., additional, Sofeya, L., additional, Stone, G., additional, Taljaard, B., additional, Tasse, C., additional, Theron, I. P., additional, Tiplady, A. J., additional, Toruvanda, O., additional, Twum, S. N., additional, Balla, T. J. van, additional, Byl, A. van der, additional, Merwe, C. van der, additional, Tonder, V. Van, additional, Wallace, B. H., additional, Welz, M. G., additional, Williams, L. P., additional, and Xaia, B., additional

Published
2020
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18. The MeerKAT telescope as a pulsar facility: System verification and early science results from MeerTime

Author

Bailes, M., primary, Jameson, A., additional, Abbate, F., additional, Barr, E. D., additional, Bhat, N. D. R., additional, Bondonneau, L., additional, Burgay, M., additional, Buchner, S. J., additional, Camilo, F., additional, Champion, D. J., additional, Cognard, I., additional, Demorest, P. B., additional, Freire, P. C. C., additional, Gautam, T., additional, Geyer, M., additional, Griessmeier, J.-M., additional, Guillemot, L., additional, Hu, H., additional, Jankowski, F., additional, Johnston, S., additional, Karastergiou, A., additional, Karuppusamy, R., additional, Kaur, D., additional, Keith, M. J., additional, Kramer, M., additional, van Leeuwen, J., additional, Lower, M. E., additional, Maan, Y., additional, McLaughlin, M. A., additional, Meyers, B. W., additional, Osłowski, S., additional, Oswald, L. S., additional, Parthasarathy, A., additional, Pennucci, T., additional, Posselt, B., additional, Possenti, A., additional, Ransom, S. M., additional, Reardon, D. J., additional, Ridolfi, A., additional, Schollar, C. T. G., additional, Serylak, M., additional, Shaifullah, G., additional, Shamohammadi, M., additional, Shannon, R. M., additional, Sobey, C., additional, Song, X., additional, Spiewak, R., additional, Stairs, I. H., additional, Stappers, B. W., additional, van Straten, W., additional, Szary, A., additional, Theureau, G., additional, Venkatraman Krishnan, V., additional, Weltevrede, P., additional, Wex, N., additional, Abbott, T. D., additional, Adams, G. B., additional, Burger, J. P., additional, Gamatham, R. R. G., additional, Gouws, M., additional, Horn, D. M., additional, Hugo, B., additional, Joubert, A. F., additional, Manley, J. R., additional, McAlpine, K., additional, Passmoor, S. S., additional, Peens-Hough, A., additional, Ramudzuli, Z. R, additional, Rust, A., additional, Salie, S., additional, Schwardt, L. C., additional, Siebrits, R., additional, Van Tonder, G., additional, Van Tonder, V., additional, and Welz, M. G., additional

Published
2020
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20. Cash Use of the Taiwan Dollar

Author

Franses, Ph.H.B.F. (Philip Hans), Welz, M. (Max), Franses, Ph.H.B.F. (Philip Hans), and Welz, M. (Max)

Abstract

Two banknotes and two coins of the New Taiwan Dollar are infrequently (if at all) used in Taiwan when people make cash payments. This note examines the effect of this behavior on the efficiency of cash payments. The results are compared with the Euro, where the two highest and two lowest tokens are also rarely used. We find for Taiwan that inefficiency increases with 60.7%, while for the Euro it is only 25.3%. The main reason is that two of the rarely used coins and notes in Taiwan are in the middle of the denominational range, whereas for the Euro, these tokens concern the ends of that range.

Published
2019
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21. Cash use of the Taiwan dollar: Is it efficient?

Author

Franses, Ph.H.B.F. (Philip Hans), Welz, M., Franses, Ph.H.B.F. (Philip Hans), and Welz, M.

Abstract

Two banknotes and two coins of the New Taiwan Dollar are infrequently (if at all) used in Taiwan when people make cash payments. This note examines the effect of this behavior on the efficiency of cash payments. The results are compared with the Euro, where the two highest and two lowest tokens are also rarely used. We find for Taiwan that inefficiency increases with 60.7%, while for the Euro it is only 25.3%. The main reason is that two of the rarely used coins and notes in Taiwan are in the middle of the denominational range, whereas for the Euro, these tokens concern the ends of that range.

Published
2019

22. Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event

Author

Heywood, I., primary, Camilo, F., additional, Cotton, W. D., additional, Yusef-Zadeh, F., additional, Abbott, T. D., additional, Adam, R. M., additional, Aldera, M. A., additional, Bauermeister, E. F., additional, Booth, R. S., additional, Botha, A. G., additional, Botha, D. H., additional, Brederode, L. R. S., additional, Brits, Z. B., additional, Buchner, S. J., additional, Burger, J. P., additional, Chalmers, J. M., additional, Cheetham, T., additional, de Villiers, D., additional, Dikgale-Mahlakoana, M. A., additional, du Toit, L. J., additional, Esterhuyse, S. W. P., additional, Fanaroff, B. L., additional, Foley, A. R., additional, Fourie, D. J., additional, Gamatham, R. R. G., additional, Goedhart, S., additional, Gounden, S., additional, Hlakola, M. J., additional, Hoek, C. J., additional, Hokwana, A., additional, Horn, D. M., additional, Horrell, J. M. G., additional, Hugo, B., additional, Isaacson, A. R., additional, Jonas, J. L., additional, Jordaan, J. D. B. L., additional, Joubert, A. F., additional, Józsa, G. I. G., additional, Julie, R. P. M., additional, Kapp, F. B., additional, Kenyon, J. S., additional, Kotzé, P. P. A., additional, Kriel, H., additional, Kusel, T. W., additional, Lehmensiek, R., additional, Liebenberg, D., additional, Loots, A., additional, Lord, R. T., additional, Lunsky, B. M., additional, Macfarlane, P. S., additional, Magnus, L. G., additional, Magozore, C. M., additional, Mahgoub, O., additional, Main, J. P. L., additional, Malan, J. A., additional, Malgas, R. D., additional, Manley, J. R., additional, Maree, M. D. J., additional, Merry, B., additional, Millenaar, R., additional, Mnyandu, N., additional, Moeng, I. P. T., additional, Monama, T. E., additional, Mphego, M. C., additional, New, W. S., additional, Ngcebetsha, B., additional, Oozeer, N., additional, Otto, A. J., additional, Passmoor, S. S., additional, Patel, A. A., additional, Peens-Hough, A., additional, Perkins, S. J., additional, Ratcliffe, S. M., additional, Renil, R., additional, Rust, A., additional, Salie, S., additional, Schwardt, L. C., additional, Serylak, M., additional, Siebrits, R., additional, Sirothia, S. K., additional, Smirnov, O. M., additional, Sofeya, L., additional, Swart, P. S., additional, Tasse, C., additional, Taylor, D. T., additional, Theron, I. P., additional, Thorat, K., additional, Tiplady, A. J., additional, Tshongweni, S., additional, van Balla, T. J., additional, van der Byl, A., additional, van der Merwe, C., additional, van Dyk, C. L., additional, Van Rooyen, R., additional, Van Tonder, V., additional, Van Wyk, R., additional, Wallace, B. H., additional, Welz, M. G., additional, and Williams, L. P., additional

Published
2019
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23. Perforin inhibition protects from lethal endothelial damage during fulminant viral hepatitis

Author

Welz, M, Eickhoff, S, Abdullah, Z, Trebicka, J, Gartlan, KH, Spicer, JA, Demetris, AJ, Akhlaghi, H, Anton, M, Manske, K, Zehn, D, Nieswandt, B, Kurts, C, Trapani, JA, Knolle, P, Wohlleber, D, Kastenmueller, W, Welz, M, Eickhoff, S, Abdullah, Z, Trebicka, J, Gartlan, KH, Spicer, JA, Demetris, AJ, Akhlaghi, H, Anton, M, Manske, K, Zehn, D, Nieswandt, B, Kurts, C, Trapani, JA, Knolle, P, Wohlleber, D, and Kastenmueller, W

Abstract

CD8 T cells protect the liver against viral infection, but can also cause severe liver damage that may even lead to organ failure. Given the lack of mechanistic insights and specific treatment options in patients with acute fulminant hepatitis, we develop a mouse model reflecting a severe acute virus-induced CD8 T cell-mediated hepatitis. Here we show that antigen-specific CD8 T cells induce liver damage in a perforin-dependent manner, yet liver failure is not caused by effector responses targeting virus-infected hepatocytes alone. Additionally, CD8 T cell mediated elimination of cross-presenting liver sinusoidal endothelial cells causes endothelial damage that leads to a dramatically impaired sinusoidal perfusion and indirectly to hepatocyte death. With the identification of perforin-mediated killing as a critical pathophysiologic mechanism of liver failure and the protective function of a new class of perforin inhibitor, our study opens new potential therapeutic angles for fulminant viral hepatitis.

Published
2018

25. Dissemination of Reference Signals for a Next Generation Radio Telescope

Author

Siebrits, R., primary, Burger, J.P., additional, Adams, G., additional, Gamatham, R., additional, Kapp, F., additional, Abbott, T., additional, Malan, S., additional, Bauermeister, E., additional, Boyana, L., additional, Kriel, H., additional, Welz, M., additional, Mnyandu, N., additional, Otto, A. J., additional, Vander Merwe, C., additional, Tshongweni, S., additional, and Gibbon, T., additional

Published
2018
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27. High Performance Time Synchronisation for Industrial Logic Control Utilising a Low Cost Single Board Computer with EMC Compliance

Author

Adams, G., primary, Kapp, F., additional, Mnyandu, N., additional, Tshongweni, S., additional, Otto, A. J., additional, van der Merwe, C., additional, Siebrits, R., additional, Bauermeister, E., additional, Boyana, L., additional, Malan, S., additional, Welz, M., additional, van Wyk, R., additional, Gamatham, R., additional, and Burger, J.P., additional

Published
2018
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28. Revival of the Magnetar PSR J1622–4950: Observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

Author

Camilo, F., primary, Scholz, P., additional, Serylak, M., additional, Buchner, S., additional, Merryfield, M., additional, Kaspi, V. M., additional, Archibald, R. F., additional, Bailes, M., additional, Jameson, A., additional, Straten, W. van, additional, Sarkissian, J., additional, Reynolds, J. E., additional, Johnston, S., additional, Hobbs, G., additional, Abbott, T. D., additional, Adam, R. M., additional, Adams, G. B., additional, Alberts, T., additional, Andreas, R., additional, Asad, K. M. B., additional, Baker, D. E., additional, Baloyi, T., additional, Bauermeister, E. F., additional, Baxana, T., additional, Bennett, T. G. H., additional, Bernardi, G., additional, Booisen, D., additional, Booth, R. S., additional, Botha, D. H., additional, Boyana, L., additional, Brederode, L. R. S., additional, Burger, J. P., additional, Cheetham, T., additional, Conradie, J., additional, Conradie, J. P., additional, Davidson, D. B., additional, Bruin, G. De, additional, Swardt, B. de, additional, Villiers, C. de, additional, Villiers, D. I. L. de, additional, Villiers, M. S. de, additional, Villiers, W. de, additional, Waal, C. De, additional, Dikgale, M. A., additional, Toit, G. du, additional, Toit, L. J. du, additional, Esterhuyse, S. W. P., additional, Fanaroff, B., additional, Fataar, S., additional, Foley, A. R., additional, Foster, G., additional, Fourie, D., additional, Gamatham, R., additional, Gatsi, T., additional, Geschke, R., additional, Goedhart, S., additional, Grobler, T. L., additional, Gumede, S. C., additional, Hlakola, M. J., additional, Hokwana, A., additional, Hoorn, D. H., additional, Horn, D., additional, Horrell, J., additional, Hugo, B., additional, Isaacson, A., additional, Jacobs, O., additional, van Rensburg, J. P. Jansen, additional, Jonas, J. L., additional, Jordaan, B., additional, Joubert, A., additional, Joubert, F., additional, Józsa, G. I. G., additional, Julie, R., additional, Julius, C. C., additional, Kapp, F., additional, Karastergiou, A., additional, Karels, F., additional, Kariseb, M., additional, Karuppusamy, R., additional, Kasper, V., additional, Knox-Davies, E. C., additional, Koch, D., additional, Kotzé, P. P. A., additional, Krebs, A., additional, Kriek, N., additional, Kriel, H., additional, Kusel, T., additional, Lamoor, S., additional, Lehmensiek, R., additional, Liebenberg, D., additional, Liebenberg, I., additional, Lord, R. T., additional, Lunsky, B., additional, Mabombo, N., additional, Macdonald, T., additional, Macfarlane, P., additional, Madisa, K., additional, Mafhungo, L., additional, Magnus, L. G., additional, Magozore, C., additional, Mahgoub, O., additional, Main, J. P. L., additional, Makhathini, S., additional, Malan, J. A., additional, Malgas, P., additional, Manley, J. R., additional, Manzini, M., additional, Marais, L., additional, Marais, N., additional, Marais, S. J., additional, Maree, M., additional, Martens, A., additional, Matshawule, S. D., additional, Matthysen, N., additional, Mauch, T., additional, Nally, L. D. Mc, additional, Merry, B., additional, Millenaar, R. P., additional, Mjikelo, C., additional, Mkhabela, N., additional, Mnyandu, N., additional, Moeng, I. T., additional, Mokone, O. J., additional, Monama, T. E., additional, Montshiwa, K., additional, Moss, V., additional, Mphego, M., additional, New, W., additional, Ngcebetsha, B., additional, Ngoasheng, K., additional, Niehaus, H., additional, Ntuli, P., additional, Nzama, A., additional, Obies, F., additional, Obrocka, M., additional, Ockards, M. T., additional, Olyn, C., additional, Oozeer, N., additional, Otto, A. J., additional, Padayachee, Y., additional, Passmoor, S., additional, Patel, A. A., additional, Paula, S., additional, Peens-Hough, A., additional, Pholoholo, B., additional, Prozesky, P., additional, Rakoma, S., additional, Ramaila, A. J. T., additional, Rammala, I., additional, Ramudzuli, Z. R., additional, Rasivhaga, M., additional, Ratcliffe, S., additional, Reader, H. C., additional, Renil, R., additional, Richter, L., additional, Robyntjies, A., additional, Rosekrans, D., additional, Rust, A., additional, Salie, S., additional, Sambu, N., additional, Schollar, C. T. G., additional, Schwardt, L., additional, Seranyane, S., additional, Sethosa, G., additional, Sharpe, C., additional, Siebrits, R., additional, Sirothia, S. K., additional, Slabber, M. J., additional, Smirnov, O., additional, Smith, S., additional, Sofeya, L., additional, Songqumase, N., additional, Spann, R., additional, Stappers, B., additional, Steyn, D., additional, Steyn, T. J., additional, Strong, R., additional, Struthers, A., additional, Stuart, C., additional, Sunnylall, P., additional, Swart, P. S., additional, Taljaard, B., additional, Tasse, C., additional, Taylor, G., additional, Theron, I. P., additional, Thondikulam, V., additional, Thorat, K., additional, Tiplady, A., additional, Toruvanda, O., additional, Aardt, J. van, additional, Balla, T. van, additional, Heever, L. van den, additional, Byl, A. van der, additional, Merwe, C. van der, additional, Merwe, P. van der, additional, Niekerk, P. C. van, additional, Rooyen, R. van, additional, Staden, J. P. van, additional, Tonder, V. van, additional, Wyk, R. van, additional, Wait, I., additional, Walker, A. L., additional, Wallace, B., additional, Welz, M., additional, Williams, L. P., additional, Xaia, B., additional, Young, N., additional, and Zitha, S., additional

Published
2018
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34. Engineering and science highlights of the KAT-7 radio telescope

Author

Foley, A. R., primary, Alberts, T., additional, Armstrong, R. P., additional, Barta, A., additional, Bauermeister, E. F., additional, Bester, H., additional, Blose, S., additional, Booth, R. S., additional, Botha, D. H., additional, Buchner, S. J., additional, Carignan, C., additional, Cheetham, T., additional, Cloete, K., additional, Coreejes, G., additional, Crida, R. C., additional, Cross, S. D., additional, Curtolo, F., additional, Dikgale, A., additional, de Villiers, M. S., additional, du Toit, L. J., additional, Esterhuyse, S. W. P., additional, Fanaroff, B., additional, Fender, R. P., additional, Fijalkowski, M., additional, Fourie, D., additional, Frank, B., additional, George, D., additional, Gibbs, P., additional, Goedhart, S., additional, Grobbelaar, J., additional, Gumede, S. C., additional, Herselman, P., additional, Hess, K. M., additional, Hoek, N., additional, Horrell, J., additional, Jonas, J. L., additional, Jordaan, J. D. B., additional, Julie, R., additional, Kapp, F., additional, Kotzé, P., additional, Kusel, T., additional, Langman, A., additional, Lehmensiek, R., additional, Liebenberg, D., additional, Liebenberg, I. J. V., additional, Loots, A., additional, Lord, R. T., additional, Lucero, D. M., additional, Ludick, J., additional, Macfarlane, P., additional, Madlavana, M., additional, Magnus, L., additional, Magozore, C., additional, Malan, J. A., additional, Manley, J. R., additional, Marais, L., additional, Marais, N., additional, Marais, S. J., additional, Maree, M., additional, Martens, A., additional, Mokone, O., additional, Moss, V., additional, Mthembu, S., additional, New, W., additional, Nicholson, G. D., additional, van Niekerk, P. C., additional, Oozeer, N., additional, Passmoor, S. S., additional, Peens-Hough, A., additional, Pińska, A. B., additional, Prozesky, P., additional, Rajan, S., additional, Ratcliffe, S., additional, Renil, R., additional, Richter, L. L., additional, Rosekrans, D., additional, Rust, A., additional, Schröder, A. C., additional, Schwardt, L. C., additional, Seranyane, S., additional, Serylak, M., additional, Shepherd, D. S., additional, Siebrits, R., additional, Sofeya, L., additional, Spann, R., additional, Springbok, R., additional, Swart, P. S., additional, Thondikulam, Venkatasubramani L., additional, Theron, I. P., additional, Tiplady, A., additional, Toruvanda, O., additional, Tshongweni, S., additional, van den Heever, L., additional, van der Merwe, C., additional, van Rooyen, R., additional, Wakhaba, S., additional, Walker, A. L., additional, Welz, M., additional, Williams, L., additional, Wolleben, M., additional, Woudt, P. A., additional, Young, N. J., additional, and Zwart, J. T. L., additional

Published
2016
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35. LOCAL REGULATORS OF SEASONAL REPRODUCTION PROCESSES IN UTERUS MASCULINUS OF AN ADULT MALE EUROPEAN BISON (BISON BONASUS, LINNAEUS 1758).

Author

TABECKA-LONCZYNSKA, A., MYTYCH, J., SOLEK, P., ABRACHAMOWICZ, A., WELZ, M., and KOZIOROWSKI, M.

Subjects
REPRODUCTION, NERVE growth factor, HYPOXIA-inducible factor 1, CLOTHO (Greek deity), VASCULAR endothelial growth factors
Abstract

Growth factors, hypoxia-inducible factor 1-alpha (HIF-1α) and klotho protein all have very important functions in the male reproduction; however their role in the regulation of seasonal reproductive processes in the male European bison remains unclear. Similarly, although the uterus masculinus is very frequently found in the bison, its importance and functions remain unknown. It is likely that, this organ may have secretory functions and thus be a target for various regulatory factors. Therefore, the aim of this study was to investigate expression and activity of several factors: vascular endothelial growth factor (VEGF-A), fibroblast growth factor (FGF-2), transforming growth factor β1 (TGF-β1), nerve growth factor (NGF), insulin-like growth factor receptor (IGF-IR β), hypoxia-inducible factor 1 alpha (HIF-1α), and klotho protein in the uterus masculinus, immediately after the season of the reproductive activity (November and December). Our study reveals that the growth factor expression levels are significantly higher in November, when compared to December, while expression of HIF-1α and klotho was higher in December. These results provide novel data on differences in the expression levels of several factors in the uterus maculinus of European bison bulls after the breeding season. The described factors may, therefore, be potent regulators of the seasonal reproduction. [ABSTRACT FROM AUTHOR]

Published
2018
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42. Microsensors and mobile laboratory as instruments for computer-based health management in a pork-production chain

Author

Petersen, B, Welz, M, Rosendaal, EAM, Berns, G, and Revues Inra, Import

Subjects
[SDV.IMM] Life Sciences [q-bio]/Immunology, [SDV.BA] Life Sciences [q-bio]/Animal biology, [SDV.BA]Life Sciences [q-bio]/Animal biology, [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, [SDV.BC]Life Sciences [q-bio]/Cellular Biology, [SDV.GEN.GA] Life Sciences [q-bio]/Genetics/Animal genetics, [SDV.BC.IC] Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB], [SDV.BBM.BM] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, [SDV.GEN.GA]Life Sciences [q-bio]/Genetics/Animal genetics, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, [SDV.SPEE] Life Sciences [q-bio]/Santé publique et épidémiologie, [SDV.BC.IC]Life Sciences [q-bio]/Cellular Biology/Cell Behavior [q-bio.CB], [SDV.IMM]Life Sciences [q-bio]/Immunology, [SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], [SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie, [SDV.NEU] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC], [SDV.BC] Life Sciences [q-bio]/Cellular Biology, [SDV.MP] Life Sciences [q-bio]/Microbiology and Parasitology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
1994

45. The Case

Author

Michel Y. Dubois, Arnold B, Gordin, Welz M, Livovich J, and King La

Subjects
medicine.medical_specialty, Anesthesiology and Pain Medicine, Nursing, Nursing ethics, business.industry, medicine, Neurology (clinical), General Medicine, business
Published
2001
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