Browsing University of Hertfordshire by Author "Wu, C."

Now showing items 1-15 of 15

    • Calibration and Stokes Imaging with Full Embedded Element Primary Beam Model for the Murchison Widefield Array 

      Sokolowski, M.; Colegate, T.; Sutinjo, A. T.; Ung, D.; Wayth, R. B.; Hurley-Walker, N.; Lenc, E.; Pindor, B.; Morgan, J.; Kaplan, David L.; Bell, M. E.; Callingham, J. R.; Dwarakanath, K. S.; For, Bi-Qing; Gaensler, B. M.; Hancock, P. J.; Hindson, L.; Johnston-Hollitt, M.; Kapińska, A. D.; McKinley, B.; Offringa, A. R.; Procopio, P.; Staveley-Smith, L.; Wu, C.; Zheng, Q. (2017-11-27)
      The Murchison Widefield Array (MWA), located in Western Australia, is one of the low-frequency precursors of the international Square Kilometre Array (SKA) project. In addition to pursuing its own ambitious science program, ...

    • Extragalactic Peaked-Spectrum Radio Sources at Low Frequencies 

      Callingham, J. R.; Ekers, R. D.; Gaensler, B. M.; Line, J. L. B.; Hurley-Walker, N.; Sadler, E. M.; Tingay, S. J.; Hancock, P. J.; Bell, M. E.; Dwarakanath, K. S.; For, B. -Q.; Franzen, T. M. O.; Hindson, Luke; Johnston-Hollitt, M.; Kapinska, A. D.; Lenc, E.; McKinley, B.; Morgan, J.; Offringa, A. R.; Procopio, P.; Staveley-Smith, L.; Wayth, R. B.; Wu, C.; Zheng, Q. (2017-02-20)
      We present a sample of 1,483 sources that display spectral peaks between 72 MHz and 1.4 GHz, selected from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. The GLEAM survey is the widest ...

    • Galactic synchrotron emissivity measurements between 250° MWA 

      Su, H.; Hurley-Walker, N.; Jackson, C. A.; McClure-Griffiths, N. M.; Tingay, S. J.; Hindson, L.; Hancock, P.; Wayth, R. B.; Gaensler, B. M.; Staveley-Smith, L.; Morgan, J.; Johnston-Hollitt, M.; Lenc, E.; Bell, M. E.; Callingham, J. R.; Dwarkanath, K. S.; For, B. Q.; Kapińska, A. D.; McKinley, B.; Offringa, A. R.; Procopio, P.; Wu, C.; Zheng, Q. (2017-03-01)
      Synchrotron emission pervades the Galactic plane at low radio frequencies, originating from cosmic ray electrons interacting with the Galactic magnetic field. Using a low-frequency radio telescope, the Murchison Widefield ...

    • GLEAM : The GaLactic and Extragalactic All-sky MWA survey 

      Wayth, R. B.; Lenc, E.; Bell, M. E.; Callingham, J. R.; Dwarakanath, K. S.; Franzen, T. M. O.; For, B. -Q.; Gaensler, B.; Hancock, P.; Hindson, L.; Hurley-Walker, N.; Jackson, C. A.; Johnston-Hollitt, M.; Kapinska, A. D.; McKinley, B.; Morgan, J.; Offringa, A. R.; Procopio, P.; Staveley-Smith, L.; Wu, C.; Zheng, Q.; Trott, C. M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Corey, B. E.; Deshpande, A. A.; Emrich, D.; Goeke, R.; Greenhill, L. J.; Hazelton, B. J.; Kaplan, D. L.; Kasper, J. C.; Kratzenberg, E.; Lonsdale, C. J.; Lynch, M. J.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Ord, S. M.; Prabu, T.; Rogers, A. E. E.; Roshi, A.; Shankar, N. Udaya; Srivani, K. S.; Subrahmanyan, R.; Tingay, S. J.; Waterson, M.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L. (2015-06-22)
      GLEAM, the GaLactic and Extragalactic All-sky MWA survey, is a survey of the entire radio sky south of declination +25 deg at frequencies between 72 and 231 MHz, made with the Murchison Widefield Array (MWA) using a drift ...

    • Ionospheric modelling using GPS to calibrate the MWA. 1 : Comparison of first order ionospheric effects between GPS models and MWA observations 

      Arora, B. S.; Morgan, J.; Ord, S. M.; Tingay, S. J.; Hurley-Walker, N.; Bell, M.; Bernardi, G.; Bhat, R.; Briggs, F.; Callingham, J. R.; Deshpande, A. A.; Dwarakanath, K. S.; Ewall-Wice, A.; Feng, L.; For, B. -Q.; Hancock, P.; Hazelton, B. J.; Hindson, L.; Jacobs, D.; Johnston-Hollitt, M.; Kapińska, A. D.; Kudryavtseva, N.; Lenc, E.; McKinley, B.; Mitchell, D.; Oberoi, D.; Offringa, A. R.; Pindor, B.; Procopio, P.; Riding, J.; Staveley-Smith, L.; Wayth, R. B.; Wu, C.; Zheng, Q.; Bowman, J. D.; Cappallo, R. J.; Corey, B. E.; Emrich, D.; Goeke, R.; Greenhill, L. J.; Kaplan, D. L.; Kasper, J. C.; Kratzenberg, E.; Lonsdale, C. J.; Lynch, M. J.; McWhirter, S. R.; Morales, M. F.; Morgan, E.; Prabu, T.; Rogers, A. E. E.; Roshi, A.; Shankar, N. Udaya; Srivani, K. S.; Subrahmanyan, R.; Waterson, M.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L. (2015-08-10)
      We compare first order (refractive) ionospheric effects seen by the Murchison Widefield Array (MWA) with the ionosphere as inferred from Global Positioning System (GPS) data. The first order ionosphere manifests itself as ...

    • Ionospheric Modelling using GPS to Calibrate the MWA. II : Regional ionospheric modelling using GPS and GLONASS to estimate ionospheric gradients 

      Arora, B. S.; Morgan, J.; Ord, S. M.; Tingay, S. J.; Bell, M.; Callingham, J. R.; Dwarakanath, K. S.; For, B. -Q.; Hancock, P.; Hindson, L.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kapinska, A. D.; Lenc, E.; McKinley, B.; Offringa, A. R.; Procopio, P.; Staveley-Smith, L.; Wayth, R. B.; Wu, C.; Zheng, Q. (2016-07-13)
      We estimate spatial gradients in the ionosphere using the Global Positioning System (GPS) and GLONASS (Russian global navigation system) observations, utilising data from multiple GPS stations in the vicinity of Murchison ...

    • A Large Scale, Low Frequency Murchison Widefield Array Survey of Galactic HII regions between 260\340 

      Hindson, L.; Johnston-Hollitt, M.; Hurley-Walker, N.; Callingham, J. R.; Su, H.; Morgan, J.; Bell, M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Deshpande, A. A.; Dwarakanath, K. S.; For, B. -Q; Gaensler, B. M.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Kapinska, A. D.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; Mckinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Oberoi, D.; Offringa, A.; Ord, S. M.; Procopio, P.; Prabu, T.; UdayaShankar, N.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Zheng, Q. (2016-05-17)
      We have compiled a catalogue of HII regions detected with the Murchison Widefield Array (MWA) between 72 and 231MHz. The multiple frequency bands provided by the MWA allow us identify the characteristic spectrum generated ...

    • Limits of noise and confusion in the MWA GLEAM year 1 survey 

      Franzen, T. M. O.; Jackson, C. A.; Callingham, J. R.; Ekers, R. D.; Hancock, P. J.; Hurley-Walker, N.; Morgan, J.; Seymour, N.; Wayth, R. B.; White, S. V.; Bell, M. E.; Dwarakanath, K. S.; For, B.; Gaensler, B. M.; Hindson, L.; Johnston-Hollitt, M.; Kapinska, A. D.; Lenc, E.; McKinley, B.; Offringa, A. R.; Procopio, P.; Staveley-Smith, L.; Wu, C.; Zheng, Q. (2015-10-20)
      The GaLactic and Extragalactic All-sky MWA survey (GLEAM) is a new relatively low resolution, contiguous 72-231 MHz survey of the entire sky south of declination +25 deg. In this paper, we outline one approach to determine ...

    • Low frequency observations of linearly polarized structures in the interstellar medium near the south Galactic pole 

      Lenc, Emil; Gaensler, B. M.; Sun, X. H.; Sadler, E. M.; Willis, A. G.; Barry, N.; Beardsley, A. P.; Bell, M. E.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Callingham, J. R.; Cappallo, R. J.; Carroll, P.; Corey, B. E.; Oliveira-Costa, A. de; Deshpande, A. A.; Dillon, J. S.; Dwarkanath, K. S.; Emrich, D.; Ewall-Wice, A.; Feng, L.; For, B. -Q.; Goeke, R.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hewitt, J. N.; Hindson, L.; Hurley-Walker, N.; Johnston-Hollitt, M.; Jacobs, D. C.; Kapinska, A. D.; Kaplan, D. L.; Kasper, J. C.; Kim, H. -S.; Kratzenberg, E.; Line, J.; Loeb, A.; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Murphy, T.; Neben, A. R.; Oberoi, D.; Offringa, A. R.; Ord, S. M.; Paul, S.; Pindor, B.; Pober, J. C.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Shankar, N. Udaya; Sethi, S. K.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Sullivan, I. S.; Tegmark, M.; Thyagarajan, Nithyanandan; Tingay, S. J.; Trott, C.; Waterson, M.; Wayth, R. B.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S. B.; Zheng, Q. (2016-10-10)
      We present deep polarimetric observations at 154 MHz with the Murchison Widefield Array (MWA), covering 625 deg^2 centered on RA=0 h, Dec=-27 deg. The sensitivity available in our deep observations allows an in-band, ...

    • Low Radio Frequency Observations and Spectral Modelling of the Remnant of Supernova 1987A 

      Callingham, J. R.; Gaensler, B. M.; Zanardo, G.; Staveley-Smith, L.; Hancock, P. J.; Hurley-Walker, N.; Bell, M. E.; Dwarakanath, K. S.; Franzen, T. M. O.; Hindson, L.; Johnston-Hollitt, M.; Kapinska, A.; For, B. Q.; Lenc, E.; McKingley, B.; Offringa, A. R.; Procopio, P.; Wayth, R. B.; Wu, C.; Zheng, Q. (2016-10-11)
      We present Murchison Widefield Array observations of the supernova remnant (SNR) 1987A between 72 and 230 MHz, representing the lowest frequency observations of the source to date. This large lever arm in frequency space ...

    • The low-frequency environment of the Murchison Widefield Array : radio-frequency interference analysis and mitigation 

      Offringa, A. R.; Wayth, R. B.; Hurley-Walker, N.; Kaplan, D. L.; Barry, N.; Beardsley, A. P.; Bell, M. E.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Callingham, J. R.; Cappallo, R. J.; Carroll, P.; Deshpande, A. A.; Dillon, J. S.; Dwarakanath, K. S.; Ewall-Wice, A.; Feng, L.; For, B. -Q.; Gaensler, B. M.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hewitt, J. N.; Hindson, L.; Jacobs, D. C.; Johnston-Hollitt, M.; Kapińska, A. D.; Kim, H. -S.; Kittiwisit, P.; Lenc, E.; Line, J.; Loeb, A.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Neben, A. R.; Oberoi, D.; Ord, S. M.; Paul, S.; Pindor, B.; Pober, J. C.; Prabu, T.; Procopio, P.; Riding, J.; Shankar, N. Udaya; Sethi, S.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Sullivan, I. S.; Tegmark, M.; Thyagarajan, N.; Tingay, S. J.; Trott, C. M.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S.; Zheng, Q. (2015-01-16)
      The Murchison Widefield Array (MWA) is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations of the future Square Kilometre Array (SKA). We describe the automated radio-frequency ...

    • The radio spectral energy distribution of infrared-faint radio sources 

      Herzog, A.; Norris, R. P.; Middelberg, E.; Seymour, N.; Spitler, L. R.; Emonts, B. H. C.; Franzen, T. M. O.; Hunstead, R.; Intema, H. T.; Marvil, J.; Parker, Q. A.; Sirothia, S. K.; Hurley-Walker, N.; Bell, M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Callingham, J. R.; Deshpande, A. A.; Dwarakanath, K. S.; For, B. -Q.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hindson, L.; Johnston-Hollitt, M.; Kapinska, A. D.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Oberoi, D.; Offringa, A.; Ord, S. M.; Prabu, T.; Procopio, P.; Shankar, N. Udaya; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Zheng, Q.; Chippendale, A. P.; Harvey-Smith, L.; Heywood, I.; Indermuehle, B.; Popping, A.; Sault, R. J.; Whiting, M. T. (2016-09-01)
      Infrared-faint radio sources (IFRS) are a class of radio-loud (RL) active galactic nuclei (AGN) at high redshifts (z > 1.7) that are characterised by their relative infrared faintness, resulting in enormous radio-to-infrared ...

    • A search for long-timescale, low-frequency radio transients 

      Murphy, Tara; Kaplan, David L.; Croft, Steve; Lynch, Christene; Callingham, J. R.; Bannister, Keith; Bell, Martin E.; Hurley-Walker, Natasha; Hancock, Paul; Line, Jack; Rowlinson, Antonia; Lenc, Emil; Intema, H. T.; Jagannathan, P.; Ekers, Ronald D.; Tingay, Steven; Yuan, Fang; Wolf, Christian; Onken, Christopher A.; Dwarakanath, K. S.; For, B. -Q.; Gaensler, B. M.; Hindson, L.; Johnston-Hollitt, M.; Kapinska, A. D.; McKinley, B.; Morgan, J.; Offringa, A. R.; Procopio, P.; Staveley-Smith, L.; Wayth, R.; Wu, C.; Zheng, Q. (2017-04-11)
      We present a search for transient and highly variable sources at low radio frequencies (150-200 MHz) that explores long timescales of 1-3 years. We conducted this search by comparing the TIFR GMRT Sky Survey Alternative ...

    • Spectral energy distribution and radio halo of NGC253 at low radio frequencies 

      Kapinska, A. D.; Staveley-Smith, L.; Crocker, R.; Meurer, G. R.; Bhandari, S.; Hurley-Walker, N.; Offringa, A. R.; Hanish, D. J.; Seymour, N.; Ekers, R. D.; Bell, M. E.; Callingham, J. R.; Dwarakanath, K. S.; For, B. -Q.; Gaensler, B. M.; Hancock, P. J.; Hindson, Luke; Johnston-Hollitt, M.; Lenc, E.; McKinley, B.; Morgan, J.; Procopio, P.; Wayth, R. B.; Wu, C.; Zheng, Q.; Barry, N.; Beardsley, A. P.; Bowman, J. D.; Briggs, F.; Carroll, P.; Dillon, J. S.; Ewall-Wice, A.; Feng, L.; Greenhill, L. J.; Hazelton, B. J.; Hewitt, J. N.; Jacobs, D. J.; Kim, H. -S.; Kittiwisit, P.; Line, J.; Loeb, A.; Mitchell, D. A.; Morales, M. F.; Neben, A. R.; Paul, S.; Pindor, B.; Pober, J. C.; Riding, J.; Sethi, S. K.; Shankar, N. Udaya; Subrahmanyan, R.; Sullivan, I. S.; Tegmark, M.; Thyagarajan, N.; Tingay, S. J.; Trott, C. M.; Webster, R. L.; Wyithe, S. B. (2017-03-27)
      We present new radio continuum observations of NGC253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC253 ...

    • The Spectral Energy Distribution of Powerful Starburst Galaxies I : Modelling the Radio Continuum 

      Galvin, T J; Seymour, N.; Marvil, J.; Filipovic, M D; Tothill, N.F.H.; McDermid, Richard M.; Hurley-Walker, N.; Hancock, P. J.; Callingham, J. R.; Cook, R H; Norris, Ray P.; Bell, M E; Dwarakanath, K. S.; For, B. -Q.; Gaensler, B. M.; Hindson, L; Johnston-Hollitt, M.; Kapińska, A. D.; Lenc, E.; McKinley, B.; Morgan, J; Offringa, A. R.; Procopio, P.; Staveley-Smith, L.; Wayth, R. B.; Wu, C.; Zheng, Q. (2018-02-01)
      We have acquired radio-continuum data between 70MHz and 48 GHz for a sample of 19 southern starburst galaxies at moderate redshifts (0.067 < z < 0.227) with the aim of separating synchrotron and free-free emission components. ...