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1. The ASKAP Variables and Slow Transients (VAST) Pilot Survey

Author

Murphy, Tara, Kaplan, David L., Stewart, Adam J., O'Brien, Andrew, Lenc, Emil, Pintaldi, Sergio, Pritchard, Joshua, Dobie, Dougal, Fox, Archibald, Leung, James K., An, Tao, Bell, Martin E., Broderick, Jess W., Chatterjee, Shami, Dai, Shi, d'Antonio, Daniele, Doyle, J. Gerry, Gaensler, B. M., Heald, George, Horesh, Assaf, Jones, Megan L., McConnell, David, Moss, Vanessa A., Raja, Wasim, Ramsay, Gavin, Ryder, Stuart, Sadler, Elaine M., Sivakoff, Gregory R., Wang, Yuanming, Wang, Ziteng, Wheatland, Michael S., Whiting, Matthew, Allison, James R., Anderson, C. S., Ball, Lewis, Bannister, K., Bock, D. C. -J., Bolton, R., Bunton, J. D., Chekkala, R., Chippendale, A. P., Cooray, F. R., Gupta, N., Hayman, D. B., Jeganathan, K., Koribalski, B., Lee-Waddell, K., Mahony, Elizabeth K., Marvil, J., McClure-Griffiths, N. M., Mirtschin, P., Ng, A., Pearce, S., Phillips, C., and Voronkov, M. A.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Variables and Slow Transients Survey (VAST) on the Australian Square Kilometre Array Pathfinder (ASKAP) is designed to detect highly variable and transient radio sources on timescales from 5 seconds to $\sim 5$ years. In this paper, we present the survey description, observation strategy and initial results from the VAST Phase I Pilot Survey. This pilot survey consists of $\sim 162$ hours of observations conducted at a central frequency of 888~MHz between 2019 August and 2020 August, with a typical rms sensitivity of 0.24~mJy~beam$^{-1}$ and angular resolution of $12-20$ arcseconds. There are 113 fields, \red{each of which was observed for 12 minutes integration time}, with between 5 and 13 repeats, with cadences between 1 day and 8 months. The total area of the pilot survey footprint is 5\,131 square degrees, covering six distinct regions of the sky. An initial search of two of these regions, totalling 1\,646 square degrees, revealed 28 highly variable and/or transient sources. Seven of these are known pulsars, including the millisecond pulsar J2039--5617. Another seven are stars, four of which have no previously reported radio detection (SCR~J0533--4257, LEHPM~2-783, UCAC3~89--412162 and 2MASS J22414436--6119311). Of the remaining 14 sources, two are active galactic nuclei, six are associated with galaxies and the other six have no multiwavelength counterparts and are yet to be identified.

Published
2021
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2. Australian Square Kilometre Array Pathfinder: I. System Description

Author

Hotan, A. W., Bunton, J. D., Chippendale, A. P., Whiting, M., Tuthill, J., Moss, V. A., McConnell, D., Amy, S. W., Huynh, M. T., Allison, J. R., Anderson, C. S., Bannister, K. W., Bastholm, E., Beresford, R., Bock, D. C. -J., Bolton, R., Chapman, J. M., Chow, K., Collier, J. D., Cooray, F. R., Cornwell, T. J., Diamond, P. J., Edwards, P. G., Feain, I. J., Franzen, T. M. O., George, D., Gupta, N., Hampson, G. A., Harvey-Smith, L., Hayman, D. B., Heywood, I., Jacka, C., Jackson, C. A., Jackson, S., Jeganathan, K., Johnston, S., Kesteven, M., Kleiner, D., Koribalski, B. S., Lee-Waddell, K., Lenc, E., Lensson, E. S., Mackay, S., Mahony, E. K., McClure-Griffiths, N. M., McConigley, R., Mirtschin, P., Ng, A. K., Norris, R. P., Pearce, S. E., Phillips, C., Pilawa, M. A., Raja, W., Reynolds, J. E., Roberts, P., Roxby, D. N., Sadler, E. M., Shields, M., Schinckel, A. E. T., Serra, P., Shaw, R. D., Sweetnam, T., Troup, E. R., Tzioumis, A., Voronkov, M. A., and Westmeier, T.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

In this paper we describe the system design and capabilities of the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope at the conclusion of its construction project and commencement of science operations. ASKAP is one of the first radio telescopes to deploy phased array feed (PAF) technology on a large scale, giving it an instantaneous field of view that covers 31 square degrees at 800 MHz. As a two-dimensional array of 36x12m antennas, with baselines ranging from 22m to 6km, ASKAP also has excellent snapshot imaging capability and 10 arcsecond resolution. This, combined with 288 MHz of instantaneous bandwidth and a unique third axis of rotation on each antenna, gives ASKAP the capability to create high dynamic range images of large sky areas very quickly. It is an excellent telescope for surveys between 700 MHz and 1800 MHz and is expected to facilitate great advances in our understanding of galaxy formation, cosmology and radio transients while opening new parameter space for discovery of the unknown., Comment: 38 pages, 24 figures, accepted for publication in PASA

Published
2021
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3. The detection of an extremely bright fast radio burst in a phased array feed survey

Author

Bannister, Keith, Shannon, Ryan, Macquart, Jean-Pierre, Flynn, Chris, Edwards, Philip, O'Neill, Morgan, Osłowski, Stefan, Bailes, Matthew, Zackay, Barak, Clarke, Nathan, D'Addario, Larry, Dodson, Richard, Hall, Peter, Jameson, Andrew, Jones, Dayton, Navarro, Robert, Trinh, Joseph, Allison, James, Anderson, Craig, Bell, Martin, Chippendale, Aaron, Collier, Jordan, Heald, George, Heywood, Ian, Hotan, Aidan, Lee-Waddell, Karen, Madrid, Juan, Marvil, Joshua, McConnell, David, Popping, Attila, Voronkov, Maxim, Whiting, Matthew, Allen, Graham, Bock, Douglas, Brodrick, David, Cooray, Francis, DeBoer, David, Diamond, Philip, Ekers, Ron, Gough, Russell, Hampson, Grant, Harvey-Smith, Lisa, Hay, Stuart, Hayman, Douglas, Jackson, Carole, Johnston, Simon, Koribalski, Baerbel, McClure-Griffiths, Naomi, Mirtschin, Peter, Ng, Alan, Norris, Ray, Pearce, Sarah, Phillips, Chris, Roxby, Daniel, Troup, Euan Robert, and Westmeier, Tobias

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the detection of an ultra-bright fast radio burst (FRB) from a modest, 3.4-day pilot survey with the Australian Square Kilometre Array Pathfinder. The survey was conducted in a wide-field fly's-eye configuration using the phased-array-feed technology deployed on the array to instantaneously observe an effective area of $160$ deg$^2$, and achieve an exposure totaling $13200$ deg$^2$ hr. We constrain the position of FRB 170107 to a region $8'\times8'$ in size (90% containment) and its fluence to be $58\pm6$ Jy ms. The spectrum of the burst shows a sharp cutoff above $1400$ MHz, which could be either due to scintillation or an intrinsic feature of the burst. This confirms the existence of an ultra-bright ($>20$ Jy ms) population of FRBs., Comment: 8 pages, 4 figures, accepted in ApJ letters. Version 2: Fixed galactic coordinates in Table 2

Published
2017
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4. Astronomical verification of a stabilized frequency reference transfer system for the Square Kilometre Array

Author

Gozzard, David, Schediwy, Sascha, Dodson, Richard, Rioja, Maria, Hill, Mike, Lennon, Brett, McFee, Jock, Mirtschin, Peter, Stevens, Jamie, and Grainge, Keith

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract

In order to meet its cutting-edge scientific objectives, the Square Kilometre Array (SKA) telescope requires high-precision frequency references to be distributed to each of its antennas. The frequency references are distributed via fiber-optic links and must be actively stabilized to compensate for phase-noise imposed on the signals by environmental perturbations on the links. SKA engineering requirements demand that any proposed frequency reference distribution system be proved in "astronomical verification" tests. We present results of the astronomical verification of a stabilized frequency reference transfer system proposed for SKA-mid. The dual-receiver architecture of the Australia Telescope Compact Array was exploited to subtract the phase-noise of the sky signal from the data, allowing the phase-noise of observations performed using a standard frequency reference, as well as the stabilized frequency reference transfer system transmitting over 77 km of fiber-optic cable, to be directly compared. Results are presented for the fractional frequency stability and phase-drift of the stabilized frequency reference transfer system for celestial calibrator observations at 5 GHz and 25 GHz. These observations plus additional laboratory results for the transferred signal stability over a 166 km metropolitan fiber-optic link are used to show that the stabilized transfer system under test exceeds all SKA phase-stability requirements under a broad range of observing conditions. Furthermore, we have shown that alternative reference dissemination systems that use multiple synthesizers to supply reference signals to sub-sections of an array may limit the imaging capability of the telescope., Comment: 12 pages, accepted to The Astronomical Journal

Published
2017
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5. The Australian Square Kilometre Array Pathfinder: Performance of the Boolardy Engineering Test Array

Author

McConnell, D., Allison, J. R., Bannister, K., Bell, M. E., Bignall, H. E., Chippendale, A. P., Edwards, P. G., Harvey-Smith, L., Hegarty, S., Heywood, I., Hotan, A. W., Indermuehle, B. T., Lenc, E., Marvil, J., Popping, A., Raja, W., Reynolds, J. E., Sault, R. J., Serra, P., Voronkov, M. A., Whiting, M., Amy, S. W., Axtens, P., Ball, L., Bateman, T. J., Bock, D. C. -J., Bolton, R., Brodrick, D., Brothers, M., Brown, A. J., Bunton, J. D., Cheng, W., Cornwell, T., DeBoer, D., Feain, I., Gough, R., Gupta, N., Guzman, J. C., Hampson, G. A., Hay, S., Hayman, D. B., Hoyle, S., Humphreys, B., Jacka, C., Jackson, C. A., Jackson, S., Jeganathan, K., Joseph, J., Koribalski, B. S., Leach, M., Lensson, E. S., MacLeod, A., Mackay, S., Marquarding, M., McClure-Griffiths, N. M., Mirtschin, P., Mitchell, D., Neuhold, S., Ng, A., Norris, R., Pearce, S., Qiao, R. Y., Schinckel, A. E. T., Shields, M., Shimwell, T. W., Storey, M., Troup, E., Turner, B., Tuthill, J., Tzioumis, A., Wark, R. M., Westmeier, T., Wilson, C., and Wilson, T.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We describe the performance of the Boolardy Engineering Test Array (BETA), the prototype for the Australian Square Kilometre Array Pathfinder telescope ASKAP. BETA is the first aperture synthesis radio telescope to use phased array feed technology, giving it the ability to electronically form up to nine dual-polarization beams. We report the methods developed for forming and measuring the beams, and the adaptations that have been made to the traditional calibration and imaging procedures in order to allow BETA to function as a multi-beam aperture synthesis telescope. We describe the commissioning of the instrument and present details of BETA's performance: sensitivity, beam characteristics, polarimetric properties and image quality. We summarise the astronomical science that it has produced and draw lessons from operating BETA that will be relevant to the commissioning and operation of the final ASKAP telescope., Comment: Accepted for publication in PASA

Published
2016
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6. Wide-field broadband radio imaging with phased array feeds: a pilot multi-epoch continuum survey with ASKAP-BETA

Author

Heywood, I., Bannister, K. W., Marvil, J., Allison, J. R., Ball, L., Bell, M. E., Bock, D. C. -J., Brothers, M., Bunton, J. D., Chippendale, A. P., Cooray, F., Cornwell, T. J., DeBoer, D., Edwards, P., Gough, R., Gupta, N., Harvey-Smith, L., Hay, S., Hotan, A. W., Indermuehle, B., Jacka, C., Jackson, C. A., Johnston, S., Kimball, A. E., Koribalski, B. S., Lenc, E., Macleod, A., McClure-Griffiths, N., McConnell, D., Mirtschin, P., Murphy, T., Neuhold, S., Norris, R. P., Pearce, S., Popping, A., Qiao, R. Y., Reynolds, J. E., Sadler, E. M., Sault, R. J., Schinckel, A. E. T., Serra, P., Shimwell, T. W., Stevens, J., Tuthill, J., Tzioumis, A., Voronkov, M. A., Westmeier, T., and Whiting, M. T.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The Boolardy Engineering Test Array is a 6 x 12 m dish interferometer and the prototype of the Australian Square Kilometre Array Pathfinder (ASKAP), equipped with the first generation of ASKAP's phased array feed (PAF) receivers. These facilitate rapid wide-area imaging via the deployment of simultaneous multiple beams within a 30 square degree field of view. By cycling the array through 12 interleaved pointing positions and using 9 digitally formed beams we effectively mimic a traditional 1 hour x 108 pointing survey, covering 150 square degrees over 711 - 1015 MHz in 12 hours of observing time. Three such observations were executed over the course of a week. We verify the full bandwidth continuum imaging performance and stability of the system via self-consistency checks and comparisons to existing radio data. The combined three epoch image has arcminute resolution and a 1-sigma thermal noise level of 375 micro-Jy per beam, although the effective noise is a factor 3 higher due to residual sidelobe confusion. From this we derive a catalogue of 3,722 discrete radio components, using the 35 percent fractional bandwidth to measure in-band spectral indices for 1,037 of them. A search for transient events reveals one significantly variable source within the survey area. The survey covers approximately two-thirds of the Spitzer South Pole Telescope Deep Field. This pilot project demonstrates the viability and potential of using PAFs to rapidly and accurately survey the sky at radio wavelengths., Comment: 20 pages, 13 figures, 4 tables. Accepted for publication in MNRAS

Published
2016
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7. A pilot ASKAP survey of radio transient events in the region around the intermittent pulsar PSR J1107-5907

Author

Hobbs, G., Heywood, I., Bell, M. E., Kerr, M., Rowlinson, A., Johnston, S., Shannon, R. M., Voronkov, M. A., Ward, C., Banyer, J., Hancock, P. J., Murphy, Tara, Allison, J. R., Amy, S. W., Ball, L., Bannister, K., Bock, D. C. -J., Brodrick, D., Brothers, M., Brown, A. J., Bunton, J. D., Chapman, J., Chippendale, A. P., Chung, Y., DeBoer, D., Diamond, P., Edwards, P. G., Ekers, R., Ferris, R. H., Forsyth, R., Gough, R., Grancea, A., Gupta, N., Harvey-Smith, L., Hay, S., Hayman, D. B., Hotan, A. W., Hoyle, S., Humphreys, B., Indermuehle, B., Jacka, C. E., Jackson, C. A., Jackson, S., Jeganathan, K., Joseph, J, Kendall, R., Kiraly, D., Koribalski, B., Leach, M., Lenc, E., MacLeod, A., Mader, S., Marquarding, M., Marvil, J., McClure-Griffiths, N., McConnell, D., Mirtschin, P., Neuhold, S., Ng, A., Norris, R. P., O'Sullivan, J., Pearce, S., Phillips, C. J., Popping, A., Qiao, R. Y., Reynolds, J. E., Roberts, P., Sault, R. J., Schinckel, A. E. T., Serra, P., Shaw, R., Shimwell, T. W., Storey, M., Sweetnam, A. W., Tzioumis, A., Westmeier, T., Whiting, M., and Wilson, C. D.

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

We use observations from the Boolardy Engineering Test Array (BETA) of the Australian Square Kilometre Array Pathfinder (ASKAP) telescope to search for transient radio sources in the field around the intermittent pulsar PSR J1107-5907. The pulsar is thought to switch between an "off" state in which no emission is detectable, a weak state and a strong state. We ran three independent transient detection pipelines on two-minute snapshot images from a 13 hour BETA observation in order to 1) study the emission from the pulsar, 2) search for other transient emission from elsewhere in the image and 3) to compare the results from the different transient detection pipelines. The pulsar was easily detected as a transient source and, over the course of the observations, it switched into the strong state three times giving a typical timescale between the strong emission states of 3.7 hours. After the first switch it remained in the strong state for almost 40 minutes. The other strong states lasted less than 4 minutes. The second state change was confirmed using observations with the Parkes radio telescope. No other transient events were found and we place constraints on the surface density of such events on these timescales. The high sensitivity Parkes observations enabled us to detect individual bright pulses during the weak state and to study the strong state over a wide observing band. We conclude by showing that future transient surveys with ASKAP will have the potential to probe the intermittent pulsar population., Comment: Accepted by MNRAS

Published
2015
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8. ASKAP HI imaging of the galaxy group IC 1459

Author

Serra, P., Koribalski, B., Kilborn, V., Allison, J. R., Amy, S. W., Ball, L., Bannister, K., Bell, M. E., Bock, D. C. -J., Bolton, R., Bowen, M., Boyle, B., Broadhurst, S., Brodrick, D., Brothers, M., Bunton, J. D., Chapman, J., Cheng, W., Chippendale, A. P., Chung, Y., Cooray, F., Cornwell, T., DeBoer, D., Diamond, P., Forsyth, R., Gough, R., Gupta, N., Hampson, G. A., Harvey-Smith, L., Hay, S., Hayman, D. B., Heywood, I., Hotan, A. W., Hoyle, S., Humphreys, B., Indermuehle, B., Jacka, C., Jackson, C. A., Jackson, S., Jeganathan, K., Johnston, S., Joseph, J, Kamphuis, P., Leach, M., Lenc, E., Lensson, E., Mackay, S., Marquarding, M., Marvil, J., McClure-Griffiths, N., McConnell, D., Meyer, M., Mirtschin, P., Neuhold, S., Ng, A., Norris, R. P., O'Sullivan, J., Pathikulangara, J., Pearce, S., Phillips, C., Popping, A., Qiao, R. Y., Reynolds, J. E., Roberts, P., Sault, R. J., Schinckel, A. E. T., Shaw, R., Shimwell, T. W., Staveley-Smith, L., Storey, M., Sweetnam, A. W., Troup, E., Tzioumis, A., Voronkov, M. A., Westmeier, T., Whiting, M., Wilson, C., Wong, O. I., and Wu, X.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present HI imaging of the galaxy group IC 1459 carried out with six antennas of the Australian SKA Pathfinder equipped with phased-array feeds. We detect and resolve HI in eleven galaxies down to a column density of $\sim10^{20}$ cm$^{-2}$ inside a ~6 deg$^2$ field and with a resolution of ~1 arcmin on the sky and ~8 km/s in velocity. We present HI images, velocity fields and integrated spectra of all detections, and highlight the discovery of three HI clouds -- two in the proximity of the galaxy IC 5270 and one close to NGC 7418. Each cloud has an HI mass of $10^9$ M$_\odot$ and accounts for ~15% of the HI associated with its host galaxy. Available images at ultraviolet, optical and infrared wavelengths do not reveal any clear stellar counterpart of any of the clouds, suggesting that they are not gas-rich dwarf neighbours of IC 5270 and NGC 7418. Using Parkes data we find evidence of additional extended, low-column-density HI emission around IC 5270, indicating that the clouds are the tip of the iceberg of a larger system of gas surrounding this galaxy. This result adds to the body of evidence on the presence of intra-group gas within the IC 1459 group. Altogether, the HI found outside galaxies in this group amounts to several times $10^9$ M$_\odot$, at least 10% of the HI contained inside galaxies. This suggests a substantial flow of gas in and out of galaxies during the several billion years of the group's evolution., Comment: MNRAS accepted

Published
2015
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9. Discovery of HI gas in a young radio galaxy at $z = 0.44$ using the Australian Square Kilometre Array Pathfinder

Author

Allison, J. R., Sadler, E. M., Moss, V. A., Whiting, M. T., Hunstead, R. W., Pracy, M. B., Curran, S. J., Croom, S. M., Glowacki, M., Morganti, R., Shabala, S. S., Zwaan, M. A., Allen, G., Amy, S. W., Axtens, P., Ball, L., Bannister, K. W., Barker, S., Bell, M. E., Bock, D. C. -J., Bolton, R., Bowen, M., Boyle, B., Braun, R., Broadhurst, S., Brodrick, D., Brothers, M., Brown, A., Bunton, J. D., Cantrall, C., Chapman, J., Cheng, W., Chippendale, A. P., Chung, Y., Cooray, F., Cornwell, T., DeBoer, D., Diamond, P., Edwards, P. G., Ekers, R., Feain, I., Ferris, R. H., Forsyth, R., Gough, R., Grancea, A., Gupta, N., Guzman, J. C., Hampson, G., Harvey-Smith, L., Haskins, C., Hay, S., Hayman, D. B., Heywood, I., Hotan, A. W., Hoyle, S., Humphreys, B., Indermuehle, B. T., Jacka, C., Jackson, C., Jackson, S., Jeganathan, K., Johnston, S., Joseph, J., Kendall, R., Kesteven, M., Kiraly, D., Koribalski, B. S., Leach, M., Lenc, E., Lensson, E., Mackay, S., Macleod, A., Marquarding, M., Marvil, J., McClure-Griffiths, N., McConnell, D., Mirtschin, P., Norris, R. P., Neuhold, S., Ng, A., O'Sullivan, J., Pathikulangara, J., Pearce, S., Phillips, C., Popping, A., Qiao, R. Y., Reynolds, J. E., Roberts, P., Sault, R. J., Schinckel, A., Serra, P., Shaw, R., Shields, M., Shimwell, T., Storey, M., Sweetnam, T., Troup, E., Turner, B., Tuthill, J., Tzioumis, A., Voronkov, M. A., Westmeier, T., and Wilson, C. D.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We report the discovery of a new 21-cm HI absorption system using commissioning data from the Boolardy Engineering Test Array of the Australian Square Kilometre Array Pathfinder (ASKAP). Using the 711.5 - 1015.5 MHz band of ASKAP we were able to conduct a blind search for the 21-cm line in a continuous redshift range between $z = 0.4$ and 1.0, which has, until now, remained largely unexplored. The absorption line is detected at $z = 0.44$ towards the GHz-peaked spectrum radio source PKS B1740$-$517 and demonstrates ASKAP's excellent capability for performing a future wide-field survey for HI absorption at these redshifts. Optical spectroscopy and imaging using the Gemini-South telescope indicates that the HI gas is intrinsic to the host galaxy of the radio source. The narrow OIII emission lines show clear double-peaked structure, indicating either large-scale outflow or rotation of the ionized gas. Archival data from the \emph{XMM-Newton} satellite exhibit an absorbed X-ray spectrum that is consistent with a high column density obscuring medium around the active galactic nucleus. The HI absorption profile is complex, with four distinct components ranging in width from 5 to 300 km s$^{-1}$ and fractional depths from 0.2 to 20 per cent. In addition to systemic HI gas, in a circumnuclear disc or ring structure aligned with the radio jet, we find evidence for a possible broad outflow of neutral gas moving at a radial velocity of $v \sim 300$ km s$^{-1}$. We infer that the expanding young radio source ($t_{\rm age} \approx 2500$ yr) is cocooned within a dense medium and may be driving circumnuclear neutral gas in an outflow of $\sim$ 1 $\mathrm{M}_{\odot}$ yr$^{-1}$., Comment: 18 pages, 11 figures, accepted for publication in MNRAS

Published
2015
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10. Why Australian farmers should not kill venomous snakes.

Author

Shine, R., Dunstan, N., Abraham, J., and Mirtschin, P.

Subjects
AGRICULTURE, POISONS, AGRICULTURAL pests, SNAKEBITES, REPUTATION
Abstract

Many Australians who work outdoors (notably, farmers and graziers) routinely kill venomous snakes. We argue that this attitude is misguided and dangerous. Despite their fearsome reputation, venomous Australian snakes pose little risk to human health (snakes kill an average of less than three people per year in Australia). Also, snakes confer a substantial benefit by consuming agricultural pests such as rodents. We estimate the magnitude of that benefit with data on snake diets, feeding rates and abundances. The most valuable rodent‐controllers are Brownsnakes (genus Pseudonaja), which are rodent‐specialists as adults and are abundant in agroecosystems across much of Australia. We calculate that a free‐living adult Eastern Brownsnake consumes at least 50 mice per year (probably twice that number), and that population densities of Brownsnakes in agricultural areas can exceed 100 per km2. Thus, Brownsnakes remove thousands of mice per square kilometre of farmland per year. That offtake plausibly reduces rodent densities because Brownsnakes take all age classes and both sexes of rodents by hunting in burrows. Tolerating Brownsnakes also would benefit the environment (e.g. less reliance on toxic chemicals) and the health of humans and domestic pets (fewer rodent‐mediated diseases) and counter‐intuitively, might reduce rates of snakebite (because many bites occur when a snake is attacked). In summary, a societal policy of coexisting with highly venomous snakes would confer multiple benefits to Australian farmers. [ABSTRACT FROM AUTHOR]

Published
2024
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11. The Australian Square Kilometre Array Pathfinder: System Architecture and Specifications of the Boolardy Engineering Test Array

Author

Hotan, A. W., Bunton, J. D., Harvey-Smith, L., Humphreys, B., Jeffs, B. D., Shimwell, T., Tuthill, J., Voronkov, M., Allen, G., Amy, S., Ardern, K., Axtens, P., Ball, L., Bannister, K., Barker, S., Bateman, T., Beresford, R., Bock, D., Bolton, R., Bowen, M., Boyle, B., Braun, R., Broadhurst, S., Brodrick, D., Brooks, K., Brothers, M., Brown, A., Cantrall, C., Carrad, G., Chapman, J., Cheng, W., Chippendale, A., Chung, Y., Cooray, F., Cornwell, T., Davis, E., de Souza, L., DeBoer, D., Diamond, P., Edwards, P., Ekers, R., Feain, I., Ferris, D., Forsyth, R., Gough, R., Grancea, A., Gupta, N., Guzman, JC., Hampson, G., Haskins, C., Hay, S., Hayman, D., Hoyle, S., Jacka, C., Jackson, C., Jackson, S., Jeganathan, K., Johnston, S., Joseph, J., Kendall, R., Kesteven, M., Kiraly, D., Koribalski, B., Leach, M., Lenc, E., Lensson, E., Li, L., Mackay, S., Macleod, A., Maher, T., Marquarding, M., McClure-Griffiths, N., McConnell, D., Mickle, S., Mirtschin, P., Norris, R., Neuhold, S., Ng, A., O'Sullivan, J., Pathikulangara, J., Pearce, S., Phillips, C., Qiao, RY., Reynolds, J. E., Rispler, A., Roberts, P., Roxby, D., Schinckel, A., Shaw, R., Shields, M., Storey, M., Sweetnam, T., Troup, E., Turner, B., Tzioumis, A., Westmeier, T., Whiting, M., Wilson, C., Wilson, T., Wormnes, K., and Wu, X.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

This paper describes the system architecture of a newly constructed radio telescope - the Boolardy Engineering Test Array, which is a prototype of the Australian Square Kilometre Array Pathfinder telescope. Phased array feed technology is used to form multiple simultaneous beams per antenna, providing astronomers with unprecedented survey speed. The test array described here is a 6-antenna interferometer, fitted with prototype signal processing hardware capable of forming at least 9 dual-polarisation beams simultaneously, allowing several square degrees to be imaged in a single pointed observation. The main purpose of the test array is to develop beamforming and wide-field calibration methods for use with the full telescope, but it will also be capable of limited early science demonstrations., Comment: 17 pages, 12 figures, accepted for publication in PASA

Published
2014
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12. Comparative Studies of the Venom of a New Taipan Species, Oxyuranus temporalis, with Other Members of Its Genus

Author

Carmel M. Barber, Frank Madaras, Richard K. Turnbull, Terry Morley, Nathan Dunstan, Luke Allen, Tim Kuchel, Peter Mirtschin, and Wayne C. Hodgson

Subjects
Oxyuranus temporalis, taipan, antivenom, neurotoxicity, snake, venom, Medicine
Abstract

Taipans are highly venomous Australo-Papuan elapids. A new species of taipan, the Western Desert Taipan (Oxyuranus temporalis), has been discovered with two specimens housed in captivity at the Adelaide Zoo. This study is the first investigation of O. temporalis venom and seeks to characterise and compare the neurotoxicity, lethality and biochemical properties of O. temporalis venom with other taipan venoms. Analysis of O. temporalis venom using size-exclusion and reverse-phase HPLC indicated a markedly simplified “profile” compared to other taipan venoms. SDS-PAGE and agarose gel electrophoresis analysis also indicated a relatively simple composition. Murine LD50 studies showed that O. temporalis venom is less lethal than O. microlepidotus venom. Venoms were tested in vitro, using the chick biventer cervicis nerve-muscle preparation. Based on t90 values, O. temporalis venom is highly neurotoxic abolishing indirect twitches far more rapidly than other taipan venoms. O. temporalis venom also abolished responses to exogenous acetylcholine and carbachol, indicating the presence of postsynaptic neurotoxins. Prior administration of CSL Taipan antivenom (CSL Limited) neutralised the inhibitory effects of all taipan venoms. The results of this study suggest that the venom of the O. temporalis is highly neurotoxic in vitro and may contain procoagulant toxins, making this snake potentially dangerous to humans.

Published
2014
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13. The ASKAP Variables and Slow Transients (VAST) Pilot Survey

Author

Murphy, T, Kaplan, DL, Stewart, AJ, O'Brien, A, Lenc, E, Pintaldi, S, Pritchard, J, Dobie, D, Fox, A, Leung, JK, An, T, Bell, ME, Broderick, JW, Chatterjee, S, Dai, S, D'Antonio, D, Doyle, G, Gaensler, BM, Heald, G, Horesh, A, Jones, ML, McConnell, D, Moss, VA, Raja, W, Ramsay, G, Ryder, S, Sadler, EM, Sivakoff, GR, Wang, Y, Wang, Z, Wheatland, MS, Whiting, M, Allison, JR, Anderson, CS, Ball, L, Bannister, K, Bock, DCJ, Bolton, R, Bunton, JD, Chekkala, R, Chippendale, AP, Cooray, FR, Gupta, N, Hayman, DB, Jeganathan, K, Koribalski, B, Lee-Waddell, K, Mahony, EK, Marvil, J, McClure-Griffiths, NM, Mirtschin, P, Ng, A, Pearce, S, Phillips, C, Voronkov, MA, Murphy, T, Kaplan, DL, Stewart, AJ, O'Brien, A, Lenc, E, Pintaldi, S, Pritchard, J, Dobie, D, Fox, A, Leung, JK, An, T, Bell, ME, Broderick, JW, Chatterjee, S, Dai, S, D'Antonio, D, Doyle, G, Gaensler, BM, Heald, G, Horesh, A, Jones, ML, McConnell, D, Moss, VA, Raja, W, Ramsay, G, Ryder, S, Sadler, EM, Sivakoff, GR, Wang, Y, Wang, Z, Wheatland, MS, Whiting, M, Allison, JR, Anderson, CS, Ball, L, Bannister, K, Bock, DCJ, Bolton, R, Bunton, JD, Chekkala, R, Chippendale, AP, Cooray, FR, Gupta, N, Hayman, DB, Jeganathan, K, Koribalski, B, Lee-Waddell, K, Mahony, EK, Marvil, J, McClure-Griffiths, NM, Mirtschin, P, Ng, A, Pearce, S, Phillips, C, and Voronkov, MA

Abstract

The Variables and Slow Transients Survey (VAST) on the Australian Square Kilometre Array Pathfinder (ASKAP) is designed to detect highly variable and transient radio sources on timescales from 5 s to ~5 yr. In this paper, we present the survey description, observation strategy and initial results from the VAST Phase I Pilot Survey. This pilot survey consists of ~162 h of observations conducted at a central frequency of 888 MHz between 2019 August and 2020 August, with a typical rms sensitivity of 0.24 mJy beam-1 and angular resolution of 12 -20 arcseconds. There are 113 fields, each of which was observed for 12 min integration time, with between 5 and 13 repeats, with cadences between 1 day and 8 months. The total area of the pilot survey footprint is 5 131 square degrees, covering six distinct regions of the sky. An initial search of two of these regions, totalling 1 646 square degrees, revealed 28 highly variable and/or transient sources. Seven of these are known pulsars, including the millisecond pulsar J2039-5617. Another seven are stars, four of which have no previously reported radio detection (SCR J0533-4257, LEHPM 2-783, UCAC3 89-412162 and 2MASS J22414436-6119311). Of the remaining 14 sources, two are active galactic nuclei, six are associated with galaxies and the other six have nomulti-wavelength counterparts and are yet to be identified.

Published
2021

16. The ASKAP Variables and Slow Transients (VAST) Pilot Survey

Author

Murphy, Tara, primary, Kaplan, David L., additional, Stewart, Adam J., additional, O’Brien, Andrew, additional, Lenc, Emil, additional, Pintaldi, Sergio, additional, Pritchard, Joshua, additional, Dobie, Dougal, additional, Fox, Archibald, additional, Leung, James K., additional, An, Tao, additional, Bell, Martin E., additional, Broderick, Jess W., additional, Chatterjee, Shami, additional, Dai, Shi, additional, d’Antonio, Daniele, additional, Doyle, Gerry, additional, Gaensler, B. M., additional, Heald, George, additional, Horesh, Assaf, additional, Jones, Megan L., additional, McConnell, David, additional, Moss, Vanessa A., additional, Raja, Wasim, additional, Ramsay, Gavin, additional, Ryder, Stuart, additional, Sadler, Elaine M., additional, Sivakoff, Gregory R., additional, Wang, Yuanming, additional, Wang, Ziteng, additional, Wheatland, Michael S., additional, Whiting, Matthew, additional, Allison, James R., additional, Anderson, C. S., additional, Ball, Lewis, additional, Bannister, K., additional, Bock, D. C.-J., additional, Bolton, R., additional, Bunton, J. D., additional, Chekkala, R., additional, Chippendale, A. P, additional, Cooray, F. R., additional, Gupta, N., additional, Hayman, D. B., additional, Jeganathan, K., additional, Koribalski, B., additional, Lee-Waddell, K., additional, Mahony, Elizabeth K., additional, Marvil, J., additional, McClure-Griffiths, N. M., additional, Mirtschin, P., additional, Ng, A., additional, Pearce, S., additional, Phillips, C., additional, and Voronkov, M. A., additional

Published
2021
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17. Australian square kilometre array pathfinder: I. system description

Author

Hotan, A. W., primary, Bunton, J. D., additional, Chippendale, A. P., additional, Whiting, M., additional, Tuthill, J., additional, Moss, V. A., additional, McConnell, D., additional, Amy, S. W., additional, Huynh, M. T., additional, Allison, J. R., additional, Anderson, C. S., additional, Bannister, K. W., additional, Bastholm, E., additional, Beresford, R., additional, Bock, D. C.-J., additional, Bolton, R., additional, Chapman, J. M., additional, Chow, K., additional, Collier, J. D., additional, Cooray, F. R., additional, Cornwell, T. J., additional, Diamond, P. J., additional, Edwards, P. G., additional, Feain, I. J., additional, Franzen, T. M. O., additional, George, D., additional, Gupta, N., additional, Hampson, G. A., additional, Harvey-Smith, L., additional, Hayman, D. B., additional, Heywood, I., additional, Jacka, C., additional, Jackson, C. A., additional, Jackson, S., additional, Jeganathan, K., additional, Johnston, S., additional, Kesteven, M., additional, Kleiner, D., additional, Koribalski, B. S., additional, Lee-Waddell, K., additional, Lenc, E., additional, Lensson, E. S., additional, Mackay, S., additional, Mahony, E. K., additional, McClure-Griffiths, N. M., additional, McConigley, R., additional, Mirtschin, P., additional, Ng, A. K., additional, Norris, R. P., additional, Pearce, S. E., additional, Phillips, C., additional, Pilawa, M. A., additional, Raja, W., additional, Reynolds, J. E., additional, Roberts, P., additional, Roxby, D. N., additional, Sadler, E. M., additional, Shields, M., additional, Schinckel, A. E. T., additional, Serra, P., additional, Shaw, R. D., additional, Sweetnam, T., additional, Troup, E. R., additional, Tzioumis, A., additional, Voronkov, M. A., additional, and Westmeier, T., additional

Published
2021
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19. The Detection of an Extremely Bright Fast Radio Burst in a Phased Array Feed Survey

Author

Bannister, KW, Shannon, RM, Macquart, JP, Flynn, C, Edwards, PG, O'Neill, M, Osłowski, S, Bailes, M, Zackay, B, Clarke, N, D'Addario, LR, Dodson, R, Hall, PJ, Jameson, A, Jones, D, Navarro, R, Trinh, JT, Allison, J, Anderson, CS, Bell, M, Chippendale, AP, Collier, JD, Heald, G, Heywood, I, Hotan, AW, Lee-Waddell, K, Madrid, JP, Marvil, J, McConnell, D, Popping, A, Voronkov, MA, Whiting, MT, Allen, GR, Bock, DCJ, Brodrick, DP, Cooray, F, Deboer, DR, Diamond, PJ, Ekers, R, Gough, RG, Hampson, GA, Harvey-Smith, L, Hay, SG, Hayman, DB, Jackson, CA, Johnston, S, Koribalski, BS, McClure-Griffiths, NM, Mirtschin, P, Ng, A, Norris, RP, Pearce, SE, Phillips, CJ, Roxby, DN, Troup, ER, Westmeier, T, Bannister, KW, Shannon, RM, Macquart, JP, Flynn, C, Edwards, PG, O'Neill, M, Osłowski, S, Bailes, M, Zackay, B, Clarke, N, D'Addario, LR, Dodson, R, Hall, PJ, Jameson, A, Jones, D, Navarro, R, Trinh, JT, Allison, J, Anderson, CS, Bell, M, Chippendale, AP, Collier, JD, Heald, G, Heywood, I, Hotan, AW, Lee-Waddell, K, Madrid, JP, Marvil, J, McConnell, D, Popping, A, Voronkov, MA, Whiting, MT, Allen, GR, Bock, DCJ, Brodrick, DP, Cooray, F, Deboer, DR, Diamond, PJ, Ekers, R, Gough, RG, Hampson, GA, Harvey-Smith, L, Hay, SG, Hayman, DB, Jackson, CA, Johnston, S, Koribalski, BS, McClure-Griffiths, NM, Mirtschin, P, Ng, A, Norris, RP, Pearce, SE, Phillips, CJ, Roxby, DN, Troup, ER, and Westmeier, T

Abstract

© 2017. The American Astronomical Society. All rights reserved. We report the detection of an ultra-bright fast radio burst (FRB) from a modest, 3.4-day pilot survey with the Australian Square Kilometre Array Pathfinder. The survey was conducted in a wide-field fly's-eye configuration using the phased-array-feed technology deployed on the array to instantaneously observe an effective area of 160 deg2, and achieve an exposure totaling 13200 deg2 hr . We constrain the position of FRB 170107 to a region in size (90% containment) and its fluence to be 58 ±6 Jy ms. The spectrum of the burst shows a sharp cutoff above 1400 MHz, which could be due to either scintillation or an intrinsic feature of the burst. This confirms the existence of an ultra-bright (∼ Jy ms) population of FRBs.

Published
2017

20. The Detection of an Extremely Bright Fast Radio Burst in a Phased Array Feed Survey

Author

Bannister, K., Shannon, Ryan, Macquart, Jean-Pierre, Flynn, C., Edwards, P., O'Neill, M., Oslowski, S., Bailes, M., Zackay, B., Clarke, N., D'Addario, L., Dodson, R., Hall, P., Jameson, A., Jones, D., Navarro, R., Trinh, J., Allison, J., Anderson, C., Bell, M., Chippendale, A., Collier, J., Heald, G., Heywood, I., Hotan, A., Lee-Waddell, K., Madrid, J., Marvil, J., McConnell, D., Popping, A., Voronkov, M., Whiting, M., Allen, G., Bock, D., Brodrick, D., Cooray, F., Deboer, D., Diamond, P., Ekers, R., Gough, R., Hampson, G., Harvey-Smith, L., Hay, S., Hayman, D., Jackson, Carole, Johnston, S., Koribalski, B., McClure-Griffiths, N., Mirtschin, P., Ng, A., Norris, R., Pearce, S., Phillips, C., Roxby, D., Troup, E., Westmeier, T., Bannister, K., Shannon, Ryan, Macquart, Jean-Pierre, Flynn, C., Edwards, P., O'Neill, M., Oslowski, S., Bailes, M., Zackay, B., Clarke, N., D'Addario, L., Dodson, R., Hall, P., Jameson, A., Jones, D., Navarro, R., Trinh, J., Allison, J., Anderson, C., Bell, M., Chippendale, A., Collier, J., Heald, G., Heywood, I., Hotan, A., Lee-Waddell, K., Madrid, J., Marvil, J., McConnell, D., Popping, A., Voronkov, M., Whiting, M., Allen, G., Bock, D., Brodrick, D., Cooray, F., Deboer, D., Diamond, P., Ekers, R., Gough, R., Hampson, G., Harvey-Smith, L., Hay, S., Hayman, D., Jackson, Carole, Johnston, S., Koribalski, B., McClure-Griffiths, N., Mirtschin, P., Ng, A., Norris, R., Pearce, S., Phillips, C., Roxby, D., Troup, E., and Westmeier, T.

Abstract

We report the detection of an ultra-bright fast radio burst FRB)from a modest, 3.4-day pilot survey with the Australian Square Kilometre Array Pathfinder. The survey was conducted in a wide- field fly’s-eye configuration using the phased-array-feed technology deployed on the array to instantaneously observe an effective area of 160 deg2, and achieve an exposure totalling 13200 deg2 hr. We constrain the position of FRB 170107 to a region 8 ́ x 8 ́ in size(90% containment)and its fluence to be 58 ± 6 Jy ms. The spectrum of the burst shows a sharp cutoff above 1400 MHz, which could be due to either scintillation or an intrinsic feature of the burst. This confirms the existence of an ultra-bright (> 20 Jy ms) population of FRBs.

Published
2017

21. Erratum: Discovery of H I gas in a young radio galaxy at z = 0.44 using the Australian Square Kilometre Array Pathfinder

Author

Allison, J., Sadler, E., Moss, V., Whiting, M. Hunstead R., Pracy, M., Curran, S., Croom, S., Glowacki, M., Morganti, R., Shabala, S., Zwaan, M., Allen, G., Amy, S., Axtens, P., Ball, L., Bannister, K., Barker, S., Bell, M., Bock, D. Bolton R., Bowen, M., Boyle, B., Braun, R., Broadhurst, S., Brodrick, D., Brothers, M., Brown, A., Bunton, J., Cantrall, C., Chapman, J., Cheng, W., Chippendale, A., Chung, Y., Cooray, F., Cornwell, T., DeBoer, D., Diamond, P., Edwards, P., Ekers, R., Feain, I., Ferris, R., Forsyth, R., Gough, R., Grancea, A., Gupta, N., Guzman, J., Hampson, G., Harvey-Smith, L., Haskins, C., Hay, S., Hayman, D., Heywood, I., Hotan, A., Hoyle, S., Humphreys, B., Indermuehle, B., Jacka, C., Jackson, C., Jackson, S., Jeganathan, K., Johnston, S., Joseph, J., Kendall, R., Kesteven, M., Kiraly, D., Koribalski, B., Leach, M., Lenc, E., Lensson, E., Mackay, S., Macleod, A., Marquarding, M., Marvil, J., McClure-Griffiths, N., McConnell, D., Mirtschin, P., Norris, R., Neuhold, S., Ng, A., O'Sullivan, J., Pathikulangara, J., Pearce, S., Phillips, C., Popping, A., Qiao, R., Reynolds, J., Roberts, P., Sault, R., Schinckel, A., Serra, P., Shaw, R., Shields, M., Shimwell, T.W., Storey, M., Sweetnam, T., Troup, E., Turner, B., Tuthill, J., Tzioumis, A., Voronkov, M., Westmeier, T., and Wilson, C.

Published
2016

22. The Detection of an Extremely Bright Fast Radio Burst in a Phased Array Feed Survey

Author

Bannister, K. W., primary, Shannon, R. M., additional, Macquart, J.-P., additional, Flynn, C., additional, Edwards, P. G., additional, O’Neill, M., additional, Osłowski, S., additional, Bailes, M., additional, Zackay, B., additional, Clarke, N., additional, D’Addario, L. R., additional, Dodson, R., additional, Hall, P. J., additional, Jameson, A., additional, Jones, D., additional, Navarro, R., additional, Trinh, J. T., additional, Allison, J., additional, Anderson, C. S., additional, Bell, M., additional, Chippendale, A. P., additional, Collier, J. D., additional, Heald, G., additional, Heywood, I., additional, Hotan, A. W., additional, Lee-Waddell, K., additional, Madrid, J. P., additional, Marvil, J., additional, McConnell, D., additional, Popping, A., additional, Voronkov, M. A., additional, Whiting, M. T., additional, Allen, G. R., additional, Bock, D. C.-J., additional, Brodrick, D. P., additional, Cooray, F., additional, DeBoer, D. R., additional, Diamond, P. J., additional, Ekers, R., additional, Gough, R. G., additional, Hampson, G. A., additional, Harvey-Smith, L., additional, Hay, S. G., additional, Hayman, D. B., additional, Jackson, C. A., additional, Johnston, S., additional, Koribalski, B. S., additional, McClure-Griffiths, N. M., additional, Mirtschin, P., additional, Ng, A., additional, Norris, R. P., additional, Pearce, S. E., additional, Phillips, C. J., additional, Roxby, D. N., additional, Troup, E. R., additional, and Westmeier, T., additional

Published
2017
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23. Discovery of HI gas in a young radio galaxy at z = 0.44 using the Australian square kilometre array pathfinder

Author

Allison, JR, Sadler, EM, Moss, VA, Whiting, MT, Hunstead, RW, Pracy, MB, Curran, SJ, Croom, SM, Glowacki, M, Morganti, R, Shabala, SS, Zwaan, MA, Allen, G, Amy, SW, Axtens, P, Ball, L, Bannister, KW, Barker, S, Bell, ME, Bock, DCJ, Bolton, R, Bowen, M, Boyle, B, Braun, R, Broadhurst, S, Brodrick, D, Brothers, M, Brown, A, Bunton, JD, Cantrall, C, Chapman, J, Cheng, W, Chippendale, AP, Chung, Y, Cooray, F, Cornwell, T, DeBoer, D, Diamond, P, Edwards, PG, Ekers, R, Feain, I, Ferris, RH, Forsyth, R, Gough, R, Grancea, A, Gupta, N, Guzman, JC, Hampson, G, Harvey-Smith, L, Haskins, C, Hay, S, Hayman, DB, Heywood, I, Hotan, AW, Hoyle, S, Humphreys, B, Indermuehle, BT, Jacka, C, Jackson, C, Jackson, S, Jeganathan, K, Johnston, S, Joseph, J, Kendall, R, Kesteven, M, Kiraly, D, Koribalski, SB, Leach, M, Lenc, E, Lensson, E, Mackay, S, Macleod, A, Marquarding, M, Marvil, J, McClure-Griffiths, N, McConnell, D, Mirtschin, P, Norris, PR, Neuhold, S, Ng, A, O'Sullivan, J, Pathikulangara, J, Pearce, S, Phillips, C, Popping, A, Qiao, YR, Reynolds, EJ, Roberts, P, Sault, JR, Schinckel, A, Serra, P, Shaw, R, Shields, M, Shimwell, T, Storey, M, Sweetnam, T, Troup, E, Turner, B, Tuthill, J, and Tzioumis, A

Subjects
Astronomy & Astrophysics
Abstract

© 2015 The Authors. We report the discovery of a new 21-cm HI absorption system using commissioning data from the Boolardy Engineering Test Array of the Australian Square Kilometre Array Pathfinder (ASKAP). Using the 711.5-1015.5 MHz band of ASKAP we were able to conduct a blind search for the 21-cm line in a continuous redshift range between z = 0.4 and 1.0, which has, until now, remained largely unexplored. The absorption line is detected at z = 0.44 towards the GHz-peaked spectrum radio source PKS B1740-517 and demonstrates ASKAP's excellent capability for performing a future wide-field survey for HI absorption at these redshifts. Optical spectroscopy and imaging using the Gemini-South telescope indicates that the HI gas is intrinsic to the host galaxy of the radio source. The narrow [OIII] emission lines show clear double-peaked structure, indicating either large-scale outflow or rotation of the ionized gas. Archival data from the XMM-Newton satellite exhibit an absorbed X-ray spectrum that is consistent with a high column density obscuring medium around the active galactic nucleus. The HI absorption profile is complex, with four distinct components ranging in width from 5 to 300 km s-1 and fractional depths from 0.2 to 20 per cent. In addition to systemic HI gas, in a circumnuclear disc or ring structure aligned with the radio jet, we find evidence for a possible broad outflow of neutral gas moving at a radial velocity of v ~ 300 km s-1. We infer that the expanding young radio source (tage ≈ 2500 yr) is cocooned within a dense medium and may be driving circumnuclear neutral gas in an outflow of ~1 M o˙ yr-1.

Published
2015

24. A pilot ASKAP survey of radio transient events in the region around the intermittent pulsar PSR J1107-5907

Author

Hobbs, G, Heywood, I., Bell, M. E., Kerr, M, Rowlinson, A., Johnston, S., Shannon, R.M., Voronkov, M.A., Ward, C, Bannister, Keith, McClure-Griffiths, Naomi, Allison, J.R., Amy, S.W., Brodrick, D., Brothers, M., Chapman, J., Chippendale, A.P., Chung, Y., Diamond, P., Forsyth, R., Harvey-Smith, L., Hayman, D.B., Hotan, A.W., Serra, P., Hay, S., Hoyle, S., Humphreys, B., Indermuehle, B.T., Jacka, C., Jackson, S., Jeganathan, K., Joseph, J., Kendall, R., Kiraly, D., Leach, M., Macleod, A., Marvil, J., Mirtschin, P., Neuhold, S., Pearce, S., Roberts, P., Schinckel, A., Shaw, R., Storey, M., Wilson, C.D., Hobbs, G, Heywood, I., Bell, M. E., Kerr, M, Rowlinson, A., Johnston, S., Shannon, R.M., Voronkov, M.A., Ward, C, Bannister, Keith, McClure-Griffiths, Naomi, Allison, J.R., Amy, S.W., Brodrick, D., Brothers, M., Chapman, J., Chippendale, A.P., Chung, Y., Diamond, P., Forsyth, R., Harvey-Smith, L., Hayman, D.B., Hotan, A.W., Serra, P., Hay, S., Hoyle, S., Humphreys, B., Indermuehle, B.T., Jacka, C., Jackson, S., Jeganathan, K., Joseph, J., Kendall, R., Kiraly, D., Leach, M., Macleod, A., Marvil, J., Mirtschin, P., Neuhold, S., Pearce, S., Roberts, P., Schinckel, A., Shaw, R., Storey, M., and Wilson, C.D.

Abstract

We use observations from the Boolardy Engineering Test Array (BETA) of the Australian Square Kilometre Array Pathfinder (ASKAP) telescope to search for transient radio sources in the field around the intermittent pulsar PSR J1107−5907. The pulsar is thought to switch between an ‘off’ state in which no emission is detectable, a weak state and a strong state. We ran three independent transient detection pipelines on two-minute snapshot images from a 13 h BETA observation in order to (1) study the emission from the pulsar, (2) search for other transient emission from elsewhere in the image and (3) to compare the results from the different transient detection pipelines. The pulsar was easily detected as a transient source and, over the course of the observations, it switched into the strong state three times giving a typical time-scale between the strong emission states of 3.7 h. After the first switch it remained in the strong state for almost 40 min. The other strong states lasted less than 4 min. The second state change was confirmed using observations with the Parkes radio telescope. No other transient events were found and we place constraints on the surface density of such events on these time-scales. The high sensitivity Parkes observations enabled us to detect individual bright pulses during the weak state and to study the strong state over a wide observing band. We conclude by showing that future transient surveys with ASKAP will have the potential to probe the intermittent pulsar population.

Published
2016

25. Wide-field broad-band radio imaging with phased array feeds: A pilot multi-epoch continuum survey with ASKAP-BETA

Author

Heywood, I., Bannister, K., Marvil, J., Allison, J., Ball, L., Bell, M., Bock, D., Brothers, M., Bunton, J., Chippendale, A., Cooray, F., Cornwell, T., De Boer, D., Edwards, P., Gough, R., Gupta, N., Harvey-Smith, L., Hay, S., Hotan, A., Indermuehle, B., Jacka, C., Jackson, Carole, Johnston, S., Kimball, A., Koribalski, B., Lenc, E., Macleod, A., McClure-Griffiths, N., McConnell, D., Mirtschin, P., Murphy, T., Neuhold, S., Norris, R., Pearce, S., Popping, A., Qiao, R., Reynolds, J., Sadler, E., Sault, R., Schinckel, A., Serra, P., Shimwell, T., Stevens, J., Tuthill, J., Tzioumis, A., Voronkov, M., Westmeier, T., Whiting, M., Heywood, I., Bannister, K., Marvil, J., Allison, J., Ball, L., Bell, M., Bock, D., Brothers, M., Bunton, J., Chippendale, A., Cooray, F., Cornwell, T., De Boer, D., Edwards, P., Gough, R., Gupta, N., Harvey-Smith, L., Hay, S., Hotan, A., Indermuehle, B., Jacka, C., Jackson, Carole, Johnston, S., Kimball, A., Koribalski, B., Lenc, E., Macleod, A., McClure-Griffiths, N., McConnell, D., Mirtschin, P., Murphy, T., Neuhold, S., Norris, R., Pearce, S., Popping, A., Qiao, R., Reynolds, J., Sadler, E., Sault, R., Schinckel, A., Serra, P., Shimwell, T., Stevens, J., Tuthill, J., Tzioumis, A., Voronkov, M., Westmeier, T., and Whiting, M.

Abstract

The Boolardy Engineering TestArray is a 6×12mdish interferometer and the prototype of the Australian Square Kilometre Array Pathfinder (ASKAP), equipped with the first generation of ASKAP's phased array feed (PAF) receivers. These facilitate rapid wide-area imaging via the deployment of simultaneous multiple beams within an ~30 deg2 field of view. By cycling the array through 12 interleaved pointing positions and using nine digitally formed beams, we effectively mimic a traditional 1 h × 108 pointing survey, covering ~150 deg2 over 711-1015 MHz in 12 h of observing time. Three such observations were executed over the course of a week. We verify the full bandwidth continuum imaging performance and stability of the system via self-consistency checks and comparisons to existing radio data. The combined three epoch image has arcminute resolution and a 1s thermal noise level of 375 µJy beam-1, although the effective noise is a factor of ~3 higher due to residual sidelobe confusion. From this we derive a catalogue of 3722 discrete radio components, using the 35 per cent fractional bandwidth to measure in-band spectral indices for 1037 of them. A search for transient events reveals one significantly variable source within the survey area. The survey covers approximately two-thirds of the Spitzer South Pole Telescope Deep Field. This pilot project demonstrates the viability and potential of using PAFs to rapidly and accurately survey the sky at radio wavelengths.

Published
2016

26. A pilot ASKAP survey of radio transient events in the region around the intermittent pulsar PSR J1107-5907

Author

Hobbs, G., Heywood, I., Bell, M., Kerr, M., Rowlinson, A., Johnston, S., Shannon, R., Voronkov, M., Ward, C., Banyer, J., Hancock, P., Murphy, T., Allison, J., Amy, S., Ball, L., Bannister, K., Bock, D., Brodrick, D., Brothers, M., Brown, A., Bunton, J., Chapman, J., Chippendale, A., Chung, Y., DeBoer, D., Diamond, P., Edwards, P., Ekers, Ronald, Ferris, R., Forsyth, R., Gough, R., Grancea, A., Gupta, N., Harvey-Smith, L., Hay, S., Hayman, D., Hotan, A., Hoyle, S., Humphreys, B., Indermuehle, B., Jacka, C., Jackson, C., Jackson, S., Jeganathan, K., Joseph, J., Kenda, R., Kiraly, D., Koribalski, B., Leach, M., Lenc, E., MacLeod, A., Mader, S., Marquarding, M., Marvil, J., McClure-Griffiths, N., McConnell, D., Mirtschin, P., Neuhold, S., Ng, A., Norris, R., O'Sullivan, J., Pearce, S., Phillips, C., Popping, A., Qiao, R., Reynolds, J., Roberts, P., Sault, R., Schinckel, A., Serra, P., Shaw, R., Shimwel, T., Storey, M., Sweetnam, A., Tzioumis, A., Westmeier, T., Whitingl, M., Wilson, C., Hobbs, G., Heywood, I., Bell, M., Kerr, M., Rowlinson, A., Johnston, S., Shannon, R., Voronkov, M., Ward, C., Banyer, J., Hancock, P., Murphy, T., Allison, J., Amy, S., Ball, L., Bannister, K., Bock, D., Brodrick, D., Brothers, M., Brown, A., Bunton, J., Chapman, J., Chippendale, A., Chung, Y., DeBoer, D., Diamond, P., Edwards, P., Ekers, Ronald, Ferris, R., Forsyth, R., Gough, R., Grancea, A., Gupta, N., Harvey-Smith, L., Hay, S., Hayman, D., Hotan, A., Hoyle, S., Humphreys, B., Indermuehle, B., Jacka, C., Jackson, C., Jackson, S., Jeganathan, K., Joseph, J., Kenda, R., Kiraly, D., Koribalski, B., Leach, M., Lenc, E., MacLeod, A., Mader, S., Marquarding, M., Marvil, J., McClure-Griffiths, N., McConnell, D., Mirtschin, P., Neuhold, S., Ng, A., Norris, R., O'Sullivan, J., Pearce, S., Phillips, C., Popping, A., Qiao, R., Reynolds, J., Roberts, P., Sault, R., Schinckel, A., Serra, P., Shaw, R., Shimwel, T., Storey, M., Sweetnam, A., Tzioumis, A., Westmeier, T., Whitingl, M., and Wilson, C.

Abstract

We use observations from the Boolardy Engineering Test Array (BETA) of the Australian Square Kilometre Array Pathfinder (ASKAP) telescope to search for transient radio sources in the field around the intermittent pulsar PSR J1107-5907. The pulsar is thought to switch between an "off" state in which no emission is detectable, a weak state and a strong state. We ran three independent transient detection pipelines on two-minute snapshot images from a 13 hour BETA observation in order to 1) study the emission from the pulsar, 2) search for other transient emission from elsewhere in the image and 3) to compare the results from the different transient detection pipelines. The pulsar was easily detected as a transient source and, over the course of the observations, it switched into the strong state three times giving a typical timescale between the strong emission states of 3.7 hours. After the first switch it remained in the strong state for almost 40 minutes. The other strong states lasted less than 4 minutes. The second state change was confirmed using observations with the Parkes radio telescope. No other transient events were found and we place constraints on the surface density of such events on these timescales. The high sensitivity Parkes observations enabled us to detect individual bright pulses during the weak state and to study the strong state over a wide observing band. We conclude by showing that future transient surveys with ASKAP will have the potential to probe the intermittent pulsar population.

Published
2016

27. Wide-field broad-band radio imaging with phased array feeds: a pilot multi-epoch continuum survey with ASKAP-BETA

Author

Heywood, I., primary, Bannister, K. W., additional, Marvil, J., additional, Allison, J. R., additional, Ball, L., additional, Bell, M. E., additional, Bock, D. C.-J., additional, Brothers, M., additional, Bunton, J. D., additional, Chippendale, A. P., additional, Cooray, F., additional, Cornwell, T. J., additional, De Boer, D., additional, Edwards, P., additional, Gough, R., additional, Gupta, N., additional, Harvey-Smith, L., additional, Hay, S., additional, Hotan, A. W., additional, Indermuehle, B., additional, Jacka, C., additional, Jackson, C. A., additional, Johnston, S., additional, Kimball, A. E., additional, Koribalski, B. S., additional, Lenc, E., additional, Macleod, A., additional, McClure-Griffiths, N., additional, McConnell, D., additional, Mirtschin, P., additional, Murphy, T., additional, Neuhold, S., additional, Norris, R. P., additional, Pearce, S., additional, Popping, A., additional, Qiao, R. Y., additional, Reynolds, J. E., additional, Sadler, E. M., additional, Sault, R. J., additional, Schinckel, A. E. T., additional, Serra, P., additional, Shimwell, T. W., additional, Stevens, J., additional, Tuthill, J., additional, Tzioumis, A., additional, Voronkov, M. A., additional, Westmeier, T., additional, and Whiting, M. T., additional

Published
2016
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28. A pilot ASKAP survey of radio transient events in the region around the intermittent pulsar PSR J1107−5907

Author

Hobbs, G., primary, Heywood, I., additional, Bell, M. E., additional, Kerr, M., additional, Rowlinson, A., additional, Johnston, S., additional, Shannon, R. M., additional, Voronkov, M. A., additional, Ward, C., additional, Banyer, J., additional, Hancock, P. J., additional, Murphy, Tara, additional, Allison, J. R., additional, Amy, S. W., additional, Ball, L., additional, Bannister,  K., additional, Bock, D. C.-J., additional, Brodrick, D., additional, Brothers, M., additional, Brown, A. J., additional, Bunton, J. D., additional, Chapman, J., additional, Chippendale, A. P., additional, Chung, Y., additional, DeBoer, D., additional, Diamond, P., additional, Edwards, P. G., additional, Ekers, R., additional, Ferris, R. H., additional, Forsyth, R., additional, Gough, R., additional, Grancea, A., additional, Gupta, N., additional, Harvey-Smith, L., additional, Hay, S., additional, Hayman, D. B., additional, Hotan, A. W., additional, Hoyle, S., additional, Humphreys, B., additional, Indermuehle, B., additional, Jacka, C. E., additional, Jackson, C. A., additional, Jackson, S., additional, Jeganathan, K., additional, Joseph, J, additional, Kendall, R., additional, Kiraly, D., additional, Koribalski, B., additional, Leach, M., additional, Lenc, E., additional, MacLeod, A., additional, Mader, S., additional, Marquarding, M., additional, Marvil, J., additional, McClure-Griffiths, N., additional, McConnell, D., additional, Mirtschin, P., additional, Neuhold, S., additional, Ng, A., additional, Norris, R. P., additional, O'Sullivan, J., additional, Pearce, S., additional, Phillips, C. J., additional, Popping, A., additional, Qiao, R. Y., additional, Reynolds, J. E., additional, Roberts, P., additional, Sault, R. J., additional, Schinckel, A. E. T., additional, Serra, P., additional, Shaw, R., additional, Shimwell, T. W., additional, Storey, M., additional, Sweetnam, A. W., additional, Tzioumis, A., additional, Westmeier, T., additional, Whiting, M., additional, and Wilson, C. D., additional

Published
2016
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31. The Australian Square Kilometre Array Pathfinder: Performance of the Boolardy Engineering Test Array

Author

McConnell, D., primary, Allison, J. R., additional, Bannister, K., additional, Bell, M. E., additional, Bignall, H. E., additional, Chippendale, A. P., additional, Edwards, P. G., additional, Harvey-Smith, L., additional, Hegarty, S., additional, Heywood, I., additional, Hotan, A. W., additional, Indermuehle, B. T., additional, Lenc, E., additional, Marvil, J., additional, Popping, A., additional, Raja, W., additional, Reynolds, J. E., additional, Sault, R. J., additional, Serra, P., additional, Voronkov, M. A., additional, Whiting, M., additional, Amy, S. W., additional, Axtens, P., additional, Ball, L., additional, Bateman, T. J., additional, Bock, D. C.-J., additional, Bolton, R., additional, Brodrick, D., additional, Brothers, M., additional, Brown, A. J., additional, Bunton, J. D., additional, Cheng, W., additional, Cornwell, T., additional, DeBoer, D., additional, Feain, I., additional, Gough, R., additional, Gupta, N., additional, Guzman, J. C., additional, Hampson, G. A., additional, Hay, S., additional, Hayman, D. B., additional, Hoyle, S., additional, Humphreys, B., additional, Jacka, C., additional, Jackson, C. A., additional, Jackson, S., additional, Jeganathan, K., additional, Joseph, J., additional, Koribalski, B. S., additional, Leach, M., additional, Lensson, E. S., additional, MacLeod, A., additional, Mackay, S., additional, Marquarding, M., additional, McClure-Griffiths, N. M., additional, Mirtschin, P., additional, Mitchell, D., additional, Neuhold, S., additional, Ng, A., additional, Norris, R., additional, Pearce, S., additional, Qiao, R. Y., additional, Schinckel, A. E. T., additional, Shields, M., additional, Shimwell, T. W., additional, Storey, M., additional, Troup, E., additional, Turner, B., additional, Tuthill, J., additional, Tzioumis, A., additional, Wark, R. M., additional, Westmeier, T., additional, Wilson, C., additional, and Wilson, T., additional

Published
2016
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32. ASKAP HI imaging of the galaxy group IC 1459

Author

Serra, P, Koribalski, B, Kilborn, V, Allison, JR, Amy, SW, Ball, L, Bannister, K, Bell, ME, Bock, DC-J, Bolton, R, Bowen, M, Boyle, B, Broadhurst, S, Brodrick, D, Brothers, M, Bunton, JD, Chapman, J, Cheng, W, Chippendale, AP, Chung, Y, Cooray, F, Cornwell, T, DeBoer, D, Diamond, P, Forsyth, R, Gough, R, Gupta, N, Hampson, GA, Harvey-Smith, L, Hay, S, Hayman, DB, Heywood, I, Hotan, AW, Hoyle, S, Humphreys, B, Indermuehle, B, Jacka, C, Jackson, CA, Jackson, S, Jeganathan, K, Johnston, S, Joseph, J, Kamphuis, P, Leach, M, Lenc, E, Lensson, E, Mackay, S, Marquarding, M, Marvil, J, McClure-Griffiths, N, McConnell, D, Meyer, M, Mirtschin, P, Neuhold, S, Ng, A, Norris, RP, O'Sullivan, J, Pathikulangara, J, Pearce, S, Phillips, C, Popping, A, Qiao, RY, Reynolds, JE, Roberts, P, Sault, RJ, Schinckel, AET, Shaw, R, Shimwell, TW, Staveley-Smith, L, Storey, M, Sweetnam, AW, Troup, E, Tzioumis, A, Voronkov, MA, Westmeier, T, Whiting, M, Wilson, C, Wong, OI, Wu, X, Serra, P, Koribalski, B, Kilborn, V, Allison, JR, Amy, SW, Ball, L, Bannister, K, Bell, ME, Bock, DC-J, Bolton, R, Bowen, M, Boyle, B, Broadhurst, S, Brodrick, D, Brothers, M, Bunton, JD, Chapman, J, Cheng, W, Chippendale, AP, Chung, Y, Cooray, F, Cornwell, T, DeBoer, D, Diamond, P, Forsyth, R, Gough, R, Gupta, N, Hampson, GA, Harvey-Smith, L, Hay, S, Hayman, DB, Heywood, I, Hotan, AW, Hoyle, S, Humphreys, B, Indermuehle, B, Jacka, C, Jackson, CA, Jackson, S, Jeganathan, K, Johnston, S, Joseph, J, Kamphuis, P, Leach, M, Lenc, E, Lensson, E, Mackay, S, Marquarding, M, Marvil, J, McClure-Griffiths, N, McConnell, D, Meyer, M, Mirtschin, P, Neuhold, S, Ng, A, Norris, RP, O'Sullivan, J, Pathikulangara, J, Pearce, S, Phillips, C, Popping, A, Qiao, RY, Reynolds, JE, Roberts, P, Sault, RJ, Schinckel, AET, Shaw, R, Shimwell, TW, Staveley-Smith, L, Storey, M, Sweetnam, AW, Troup, E, Tzioumis, A, Voronkov, MA, Westmeier, T, Whiting, M, Wilson, C, Wong, OI, and Wu, X

Published
2015

33. Discovery of HI gas in a young radio galaxy at z = 0.44 using the Australian square kilometre array pathfinder

Author

Allison, J.R., Sadler, Elaine M, Moss, V.A., Whiting, M.T., Hunstead, Richard, Curran, S.J., Croom, Scott M, Glowacki, M., Morganti, Raffaella, Tzioumis, A K, Storey, M., Sweetnam, T., Troup, E., Turner, B., Tuthill, J., Voronkov, M.A., Westmeier, T., Wilson, C.D., Zwaan, M A, Pracy, Michael, Shabala, Stanislav S, Zwaan, M.A., Allen, G, Amy, S.W., Axtens, P., Ball, Lewis, Bannister, Keith, Barker, S., Bell, M., Bock, D. C.-J., Bolton, R., Bowen, M., Boyle, B., Braun, R., Broadhurst, S., Brodrick, D., Brothers, M., Brown, A., Bunton, John D., Cantrall, C., Chapman, J., Cheng, W., Chippendale, A.P., Chung, Y., Cooray, F., Cornwell, T., DeBoer, D., Diamond, P., Edwards, P G, Ekers, Ronald D, Feain, I, Ferris, Richard H, Forsyth, R., Gough, R, Grancea, A., Gupta, N., Guzman, J.C., Hampson, G., Harvey-Smith, L., Haskins, C., Hay, S., Hayman, D.B., Heywood, I., Hotan, A.W., Hoyle, S., Humphreys, B., Indermuehle, B.T., Jacka, C., Jackson, Carole A, Jackson, S., Jeganathan, K., Johnston, S, Joseph, J., Kendall, R., Kesteven, M J, Kiraly, D., Koribalski, Baerbel S, Leach, M., Lenc, Emil, Lensson, E., Mackay, S., Macleod, A., Marquarding, M, Marvil, J., McClure-Griffiths, Naomi, McConnell, D, Mirtschin, P., Norris, R P, Neuhold, S., Ng, A., O’Sullivan, J., Pathikulangara, Joseph, Pearce, S., Phillips, C, Popping, A., Qiao, R.Y., Reynolds, J E, Roberts, P., Sault, Robert J, Schinckel, A., Serra, P., Shaw, R., Shields, M., Shimwell, Timothy W, Allison, J.R., Sadler, Elaine M, Moss, V.A., Whiting, M.T., Hunstead, Richard, Curran, S.J., Croom, Scott M, Glowacki, M., Morganti, Raffaella, Tzioumis, A K, Storey, M., Sweetnam, T., Troup, E., Turner, B., Tuthill, J., Voronkov, M.A., Westmeier, T., Wilson, C.D., Zwaan, M A, Pracy, Michael, Shabala, Stanislav S, Zwaan, M.A., Allen, G, Amy, S.W., Axtens, P., Ball, Lewis, Bannister, Keith, Barker, S., Bell, M., Bock, D. C.-J., Bolton, R., Bowen, M., Boyle, B., Braun, R., Broadhurst, S., Brodrick, D., Brothers, M., Brown, A., Bunton, John D., Cantrall, C., Chapman, J., Cheng, W., Chippendale, A.P., Chung, Y., Cooray, F., Cornwell, T., DeBoer, D., Diamond, P., Edwards, P G, Ekers, Ronald D, Feain, I, Ferris, Richard H, Forsyth, R., Gough, R, Grancea, A., Gupta, N., Guzman, J.C., Hampson, G., Harvey-Smith, L., Haskins, C., Hay, S., Hayman, D.B., Heywood, I., Hotan, A.W., Hoyle, S., Humphreys, B., Indermuehle, B.T., Jacka, C., Jackson, Carole A, Jackson, S., Jeganathan, K., Johnston, S, Joseph, J., Kendall, R., Kesteven, M J, Kiraly, D., Koribalski, Baerbel S, Leach, M., Lenc, Emil, Lensson, E., Mackay, S., Macleod, A., Marquarding, M, Marvil, J., McClure-Griffiths, Naomi, McConnell, D, Mirtschin, P., Norris, R P, Neuhold, S., Ng, A., O’Sullivan, J., Pathikulangara, Joseph, Pearce, S., Phillips, C, Popping, A., Qiao, R.Y., Reynolds, J E, Roberts, P., Sault, Robert J, Schinckel, A., Serra, P., Shaw, R., Shields, M., and Shimwell, Timothy W

Abstract

We report the discovery of a new 21-cm HI absorption system using commissioning data from the Boolardy Engineering Test Array of the Australian Square Kilometre Array Pathfinder (ASKAP). Using the 711.5-1015.5 MHz band of ASKAP we were able to conduct a blind search for the 21-cm line in a continuous redshift range between z = 0.4 and 1.0, which has, until now, remained largely unexplored. The absorption line is detected at z = 0.44 towards the GHz-peaked spectrum radio source PKS B1740-517 and demonstrates ASKAP's excellent capability for performing a future wide-field survey for HI absorption at these redshifts. Optical spectroscopy and imaging using the Gemini-South telescope indicates that the HI gas is intrinsic to the host galaxy of the radio source. The narrow [OIII] emission lines show clear double-peaked structure, indicating either large-scale outflow or rotation of the ionized gas. Archival data from the XMM-Newton satellite exhibit an absorbed X-ray spectrum that is consistent with a high column density obscuring medium around the active galactic nucleus. The HI absorption profile is complex, with four distinct components ranging in width from 5 to 300 km s-1 and fractional depths from 0.2 to 20 per cent. In addition to systemic HI gas, in a circumnuclear disc or ring structure aligned with the radio jet, we find evidence for a possible broad outflow of neutral gas moving at a radial velocity of v ~ 300 km s-1. We infer that the expanding young radio source (tage ≈ 2500 yr) is cocooned within a dense medium and may be driving circumnuclear neutral gas in an outflow of ~1 M o˙ yr-1.

Published
2015

34. Discovery of HI gas in a young radio galaxy at z = 0.44 using the Australian Square Kilometre Array Pathfinder

Author

Allison, J., Sadler, E., Moss, V., Whiting, M., Hunstead, R., Pracy, M., Curran, S., Croom, S., Glowacki, M., Morganti, R., Shabala, S., Zwaan, M., Allen, G., Amy, S., Axtens, P., Ball, L., Bannister, K., Barker, S., Bell, M., Bock, D., Bolton, R., Bowen, M., Boyle, B., Braun, R., Broadhurst, S., Brodrick, D., Brothers, M., Brown, A., Bunton, J., Cantrall, C., Chapman, J., Cheng, W., Chippendale, A., Chung, Y., Cooray, F., Cornwell, T., DeBoer, D., Diamond, P., Edwards, P., Ekers, R., Feain, I., Ferris, R., Forsyth, R., Gough, R., Grancea, A., Gupta, N., Guzman, J., Hampson, G., Harvey-Smith, L., Haskins, C., Hay, S., Hayman, D., Heywood, I., Hotan, A., Hoyle, S., Humphreys, B., Indermuehle, B., Jacka, C., Jackson, Carole, Jackson, S., Jeganathan, K., Johnston, S., Joseph, J., Kendall, R., Kesteven, M., Kiraly, D., Koribalski, S., Leach, M., Lenc, E., Lensson, E., Mackay, S., Macleod, A., Marquarding, M., Marvil, J., McClure-Griffiths, N., McConnell, D., Mirtschin, P., Norris, P., Neuhold, S., Ng, A., O'Sullivan, J., Allison, J., Sadler, E., Moss, V., Whiting, M., Hunstead, R., Pracy, M., Curran, S., Croom, S., Glowacki, M., Morganti, R., Shabala, S., Zwaan, M., Allen, G., Amy, S., Axtens, P., Ball, L., Bannister, K., Barker, S., Bell, M., Bock, D., Bolton, R., Bowen, M., Boyle, B., Braun, R., Broadhurst, S., Brodrick, D., Brothers, M., Brown, A., Bunton, J., Cantrall, C., Chapman, J., Cheng, W., Chippendale, A., Chung, Y., Cooray, F., Cornwell, T., DeBoer, D., Diamond, P., Edwards, P., Ekers, R., Feain, I., Ferris, R., Forsyth, R., Gough, R., Grancea, A., Gupta, N., Guzman, J., Hampson, G., Harvey-Smith, L., Haskins, C., Hay, S., Hayman, D., Heywood, I., Hotan, A., Hoyle, S., Humphreys, B., Indermuehle, B., Jacka, C., Jackson, Carole, Jackson, S., Jeganathan, K., Johnston, S., Joseph, J., Kendall, R., Kesteven, M., Kiraly, D., Koribalski, S., Leach, M., Lenc, E., Lensson, E., Mackay, S., Macleod, A., Marquarding, M., Marvil, J., McClure-Griffiths, N., McConnell, D., Mirtschin, P., Norris, P., Neuhold, S., Ng, A., and O'Sullivan, J.

Abstract

We report the discovery of a new 21-cm H i absorption system using commissioning data from the Boolardy Engineering Test Array of the Australian Square Kilometre Array Pathfinder (ASKAP). Using the 711.5–1015.5 MHz band of ASKAP we were able to conduct a blind search for the 21-cm line in a continuous redshift range between z = 0.4 and 1.0, which has, until now, remained largely unexplored. The absorption line is detected at z = 0.44 towards the GHz-peaked spectrum radio source PKS B1740−517 and demonstrates ASKAP's excellent capability for performing a future wide-field survey for H i absorption at these redshifts. Optical spectroscopy and imaging using the Gemini-South telescope indicates that the H i gas is intrinsic to the host galaxy of the radio source. The narrow [O iii] emission lines show clear double-peaked structure, indicating either large-scale outflow or rotation of the ionized gas. Archival data from the XMM–Newton satellite exhibit an absorbed X-ray spectrum that is consistent with a high column density obscuring medium around the active galactic nucleus. The H i absorption profile is complex, with four distinct components ranging in width from 5 to 300 km s−1 and fractional depths from 0.2 to 20 per cent. In addition to systemic H i gas, in a circumnuclear disc or ring structure aligned with the radio jet, we find evidence for a possible broad outflow of neutral gas moving at a radial velocity of v ~ 300 km s−1. We infer that the expanding young radio source (tage ≈ 2500 yr) is cocooned within a dense medium and may be driving circumnuclear neutral gas in an outflow of ~1 M⊙ yr−1.

Published
2015

35. Erratum: Discovery of H i gas in a young radio galaxy at $\boldsymbol {z = 0.44}$ using the Australian Square Kilometre Array Pathfinder

Author

Allison, J. R., primary, Sadler, E. M., additional, Moss, V. A., additional, Whiting, M. T., additional, Hunstead, R. W., additional, Pracy, M. B., additional, Curran, S. J., additional, Croom, S. M., additional, Glowacki, M., additional, Morganti, R., additional, Shabala, S. S., additional, Zwaan, M. A., additional, Allen, G., additional, Amy, S. W., additional, Axtens, P., additional, Ball, L., additional, Bannister, K. W., additional, Barker, S., additional, Bell, M. E., additional, Bock, D. C.-J., additional, Bolton, R., additional, Bowen, M., additional, Boyle, B., additional, Braun, R., additional, Broadhurst, S., additional, Brodrick, D., additional, Brothers, M., additional, Brown, A., additional, Bunton, J. D., additional, Cantrall, C., additional, Chapman, J., additional, Cheng, W., additional, Chippendale, A. P., additional, Chung, Y., additional, Cooray, F., additional, Cornwell, T., additional, DeBoer, D., additional, Diamond, P., additional, Edwards, P. G., additional, Ekers, R., additional, Feain, I., additional, Ferris, R. H., additional, Forsyth, R., additional, Gough, R., additional, Grancea, A., additional, Gupta, N., additional, Guzman, J. C., additional, Hampson, G., additional, Harvey-Smith, L., additional, Haskins, C., additional, Hay, S., additional, Hayman, D. B., additional, Heywood, I., additional, Hotan, A. W., additional, Hoyle, S., additional, Humphreys, B., additional, Indermuehle, B. T., additional, Jacka, C., additional, Jackson, C., additional, Jackson, S., additional, Jeganathan, K., additional, Johnston, S., additional, Joseph, J., additional, Kendall, R., additional, Kesteven, M., additional, Kiraly, D., additional, Koribalski, B. S., additional, Leach, M., additional, Lenc, E., additional, Lensson, E., additional, Mackay, S., additional, Macleod, A., additional, Marquarding, M., additional, Marvil, J., additional, McClure-Griffiths, N., additional, McConnell, D., additional, Mirtschin, P., additional, Norris, R. P., additional, Neuhold, S., additional, Ng, A., additional, O'Sullivan, J., additional, Pathikulangara, J., additional, Pearce, S., additional, Phillips, C., additional, Popping, A., additional, Qiao, R. Y., additional, Reynolds, J. E., additional, Roberts, P., additional, Sault, R. J., additional, Schinckel, A., additional, Serra, P., additional, Shaw, R., additional, Shields, M., additional, Shimwell, T., additional, Storey, M., additional, Sweetnam, T., additional, Troup, E., additional, Turner, B., additional, Tuthill, J., additional, Tzioumis, A., additional, Voronkov, M. A., additional, Westmeier, T., additional, and Wilson, C. D., additional

Published
2015
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36. Discovery of H i gas in a young radio galaxy at z = 0.44 using the Australian Square Kilometre Array Pathfinder

Author

Allison, J. R., primary, Sadler, E. M., additional, Moss, V. A., additional, Whiting, M. T., additional, Hunstead, R. W., additional, Pracy, M. B., additional, Curran, S. J., additional, Croom, S. M., additional, Glowacki, M., additional, Morganti, R., additional, Shabala, S. S., additional, Zwaan, M. A., additional, Allen, G., additional, Amy, S. W., additional, Axtens, P., additional, Ball, L., additional, Bannister, K. W., additional, Barker, S., additional, Bell, M. E., additional, Bock, D. C.-J., additional, Bolton, R., additional, Bowen, M., additional, Boyle, B., additional, Braun, R., additional, Broadhurst, S., additional, Brodrick, D., additional, Brothers, M., additional, Brown, A., additional, Bunton, J. D., additional, Cantrall, C., additional, Chapman, J., additional, Cheng, W., additional, Chippendale, A. P., additional, Chung, Y., additional, Cooray, F., additional, Cornwell, T., additional, DeBoer, D., additional, Diamond, P., additional, Edwards, P. G., additional, Ekers, R., additional, Feain, I., additional, Ferris, R. H., additional, Forsyth, R., additional, Gough, R., additional, Grancea, A., additional, Gupta, N., additional, Guzman, J. C., additional, Hampson, G., additional, Harvey-Smith, L., additional, Haskins, C., additional, Hay, S., additional, Hayman, D. B., additional, Heywood, I., additional, Hotan, A. W., additional, Hoyle, S., additional, Humphreys, B., additional, Indermuehle, B. T., additional, Jacka, C., additional, Jackson, C., additional, Jackson, S., additional, Jeganathan, K., additional, Johnston, S., additional, Joseph, J., additional, Kendall, R., additional, Kesteven, M., additional, Kiraly, D., additional, Koribalski, B. S., additional, Leach, M., additional, Lenc, E., additional, Lensson, E., additional, Mackay, S., additional, Macleod, A., additional, Marquarding, M., additional, Marvil, J., additional, McClure-Griffiths, N., additional, McConnell, D., additional, Mirtschin, P., additional, Norris, R. P., additional, Neuhold, S., additional, Ng, A., additional, O'Sullivan, J., additional, Pathikulangara, J., additional, Pearce, S., additional, Phillips, C., additional, Popping, A., additional, Qiao, R. Y., additional, Reynolds, J. E., additional, Roberts, P., additional, Sault, R. J., additional, Schinckel, A., additional, Serra, P., additional, Shaw, R., additional, Shields, M., additional, Shimwell, T., additional, Storey, M., additional, Sweetnam, T., additional, Troup, E., additional, Turner, B., additional, Tuthill, J., additional, Tzioumis, A., additional, Voronkov, M. A., additional, Westmeier, T., additional, and Wilson, C. D., additional

Published
2015
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37. ASKAP H i imaging of the galaxy group IC 1459

Author

Serra, P., primary, Koribalski, B., additional, Kilborn, V., additional, Allison, J. R., additional, Amy, S. W., additional, Ball, L., additional, Bannister, K., additional, Bell, M. E., additional, Bock, D. C.-J., additional, Bolton, R., additional, Bowen, M., additional, Boyle, B., additional, Broadhurst, S., additional, Brodrick, D., additional, Brothers, M., additional, Bunton, J. D., additional, Chapman, J., additional, Cheng, W., additional, Chippendale, A. P., additional, Chung, Y., additional, Cooray, F., additional, Cornwell, T., additional, DeBoer, D., additional, Diamond, P., additional, Forsyth, R., additional, Gough, R., additional, Gupta, N., additional, Hampson, G. A., additional, Harvey-Smith, L., additional, Hay, S., additional, Hayman, D. B., additional, Heywood, I., additional, Hotan, A. W., additional, Hoyle, S., additional, Humphreys, B., additional, Indermuehle, B., additional, Jacka, C., additional, Jackson, C. A., additional, Jackson, S., additional, Jeganathan, K., additional, Johnston, S., additional, Joseph, J., additional, Kamphuis, P., additional, Leach, M., additional, Lenc, E., additional, Lensson, E., additional, Mackay, S., additional, Marquarding, M., additional, Marvil, J., additional, McClure-Griffiths, N., additional, McConnell, D., additional, Meyer, M., additional, Mirtschin, P., additional, Neuhold, S., additional, Ng, A., additional, Norris, R. P., additional, O'Sullivan, J., additional, Pathikulangara, J., additional, Pearce, S., additional, Phillips, C., additional, Popping, A., additional, Qiao, R. Y., additional, Reynolds, J. E., additional, Roberts, P., additional, Sault, R. J., additional, Schinckel, A. E. T., additional, Shaw, R., additional, Shimwell, T. W., additional, Staveley-Smith, L., additional, Storey, M., additional, Sweetnam, A. W., additional, Troup, E., additional, Tzioumis, A., additional, Voronkov, M. A., additional, Westmeier, T., additional, Whiting, M., additional, Wilson, C., additional, Wong, O. I., additional, and Wu, X., additional

Published
2015
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38. The Australian Square Kilometre Array Pathfinder: System Architecture and Specications of the Boolardy Engineering Test Array

Author

Hotan, A., Bunton, J., Harvey-Smith, L., Humphreys, B., Jeffs, B., Shimwell, T., Tuthill, J., Voronkov, M., Allen, G., Amy, S., Ardern, K., Axtens, P., Ball, L., Bannister, K., Barker, S., Bateman, T., Beresford, R., Bock, D., Bolton, R., Bowen, M., Boyle, B., Braun, R., Broadhurst, S., Brodrick, D., Brooks, K., Brothers, M., Brown, A., Cantrall, C., Carrad, G., Chapman, J., Cheng, W., Chippendale, A., Chung, Y., Cooray, F., Cornwell, T., Davis, E., de Souza, L., DeBoer, D., Diamond, P., Edwards, P., Ekers, Ronald, Feain, I., Ferris, D., Forsyth, R., Gough, R., Grancea, A., Gupta, N., Guzman, J., Hampson, G., Haskins, C., Hay, S., Hayman, D., Hoyle, S., Jacka, C., Jackson, Carole, Jackson, S., Jeganathan, K., Johnston, S., Joseph, J., Kendall, R., Kesteven, M., Kiraly, D., Koribalsky, B., Leach, M., Lenc, E., Lensson, E., Li, L., Mackay, S., Macleod, A., Maher, T., Marquarding, M., McClure-Griffiths, N., McConnell, D., Mickle, S., Mirtschin, P., Norris, R., Neuhold, S., Ng, A., O'Sullivan, J., Pathikulangara, J., Pearce, S., Phillips, C., Qiao, R., Reynolds, J., Rispler, A., Roberts, P., Roxby, D., Schinckel, A., Shaw, R., Shields, M., Storey, M., Sweetnam, T., Troupe, E., Turner, B., Tzioumis, A., Westmeier, T., Whiting, M., Wilson, C., Wilson, T., Wormnes, K., Wu, X., Hotan, A., Bunton, J., Harvey-Smith, L., Humphreys, B., Jeffs, B., Shimwell, T., Tuthill, J., Voronkov, M., Allen, G., Amy, S., Ardern, K., Axtens, P., Ball, L., Bannister, K., Barker, S., Bateman, T., Beresford, R., Bock, D., Bolton, R., Bowen, M., Boyle, B., Braun, R., Broadhurst, S., Brodrick, D., Brooks, K., Brothers, M., Brown, A., Cantrall, C., Carrad, G., Chapman, J., Cheng, W., Chippendale, A., Chung, Y., Cooray, F., Cornwell, T., Davis, E., de Souza, L., DeBoer, D., Diamond, P., Edwards, P., Ekers, Ronald, Feain, I., Ferris, D., Forsyth, R., Gough, R., Grancea, A., Gupta, N., Guzman, J., Hampson, G., Haskins, C., Hay, S., Hayman, D., Hoyle, S., Jacka, C., Jackson, Carole, Jackson, S., Jeganathan, K., Johnston, S., Joseph, J., Kendall, R., Kesteven, M., Kiraly, D., Koribalsky, B., Leach, M., Lenc, E., Lensson, E., Li, L., Mackay, S., Macleod, A., Maher, T., Marquarding, M., McClure-Griffiths, N., McConnell, D., Mickle, S., Mirtschin, P., Norris, R., Neuhold, S., Ng, A., O'Sullivan, J., Pathikulangara, J., Pearce, S., Phillips, C., Qiao, R., Reynolds, J., Rispler, A., Roberts, P., Roxby, D., Schinckel, A., Shaw, R., Shields, M., Storey, M., Sweetnam, T., Troupe, E., Turner, B., Tzioumis, A., Westmeier, T., Whiting, M., Wilson, C., Wilson, T., Wormnes, K., and Wu, X.

Abstract

This paper describes the system architecture of a newly constructed radio telescope - the Boolardy Engineer-ing Test Array, which is a prototype of the Australian Square Kilometre Array Pathnder telescope. Phasedarray feed technology is used to form multiple simultaneous beams per antenna, providing astronomerswith unprecedented survey speed. The test array described here is a 6-antenna interferometer, tted withprototype signal processing hardware capable of forming at least 9 dual-polarisation beams simultaneously,allowing several square degrees to be imaged in a single pointed observation. The main purpose of the testarray is to develop beamforming and wide-eld calibration methods for use with the full telescope, but itwill also be capable of limited early science demonstrations.

Published
2014

40. Remote access and operation of telescopes by the scientific users

Author

Edwards, P. G., additional, Amy, S., additional, Brodrick, D., additional, Carretti, E., additional, Hoyle, S., additional, Indermuehle, B., additional, McConnell, D., additional, Mader, S., additional, Mirtschin, P., additional, Preisig, B., additional, Smith, M., additional, Stevens, J., additional, Wark, R., additional, Wieringa, M., additional, and Wu, X., additional

Published
2014
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41. The Australian Square Kilometre Array Pathfinder: System Architecture and Specifications of the Boolardy Engineering Test Array

Author

Hotan, A. W., primary, Bunton, J. D., additional, Harvey-Smith, L., additional, Humphreys, B., additional, Jeffs, B. D., additional, Shimwell, T., additional, Tuthill, J., additional, Voronkov, M., additional, Allen, G., additional, Amy, S., additional, Ardern, K., additional, Axtens, P., additional, Ball, L., additional, Bannister, K., additional, Barker, S., additional, Bateman, T., additional, Beresford, R., additional, Bock, D., additional, Bolton, R., additional, Bowen, M., additional, Boyle, B., additional, Braun, R., additional, Broadhurst, S., additional, Brodrick, D., additional, Brooks, K., additional, Brothers, M., additional, Brown, A., additional, Cantrall, C., additional, Carrad, G., additional, Chapman, J., additional, Cheng, W., additional, Chippendale, A., additional, Chung, Y., additional, Cooray, F., additional, Cornwell, T., additional, Davis, E., additional, de Souza, L., additional, DeBoer, D., additional, Diamond, P., additional, Edwards, P., additional, Ekers, R., additional, Feain, I., additional, Ferris, D., additional, Forsyth, R., additional, Gough, R., additional, Grancea, A., additional, Gupta, N., additional, Guzman, J. C., additional, Hampson, G., additional, Haskins, C., additional, Hay, S., additional, Hayman, D., additional, Hoyle, S., additional, Jacka, C., additional, Jackson, C., additional, Jackson, S., additional, Jeganathan, K., additional, Johnston, S., additional, Joseph, J., additional, Kendall, R., additional, Kesteven, M., additional, Kiraly, D., additional, Koribalski, B., additional, Leach, M., additional, Lenc, E., additional, Lensson, E., additional, Li, L., additional, Mackay, S., additional, Macleod, A., additional, Maher, T., additional, Marquarding, M., additional, McClure-Griffiths, N., additional, McConnell, D., additional, Mickle, S., additional, Mirtschin, P., additional, Norris, R., additional, Neuhold, S., additional, Ng, A., additional, O’Sullivan, J., additional, Pathikulangara, J., additional, Pearce, S., additional, Phillips, C., additional, Qiao, R. Y., additional, Reynolds, J. E., additional, Rispler, A., additional, Roberts, P., additional, Roxby, D., additional, Schinckel, A., additional, Shaw, R., additional, Shields, M., additional, Storey, M., additional, Sweetnam, T., additional, Troup, E., additional, Turner, B., additional, Tzioumis, A., additional, Westmeier, T., additional, Whiting, M., additional, Wilson, C., additional, Wilson, T., additional, Wormnes, K., additional, and Wu, X., additional

Published
2014
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42. Long-distance telecom-fiber transfer of a radio-frequency reference for radio astronomy

Author

He, Yabai, Baldwin, Kenneth G. H., Orr, Brian J., Bruce Warrington, R., Wouters, Michael J., Luiten, Andre N., Mirtschin, Peter, Tzioumis, Tasso, Phillips, Chris, Stevens, Jamie, Lennon, Brett, Munting, Scott, Aben, Guido, Newlands, Thomas, and Rayner, Tim

Abstract

Very-long-baseline interferometry (VLBI) for high-resolution astronomical imaging requires phase-stable frequency references at widely separated radio-telescope antennas. For the first time to our knowledge, we have disseminated a suitable radio-frequency (RF) reference for VLBI over a “real-world” telecom optical-fiber link between radio telescopes that are >100  km apart, by means of an innovative phase-conjugation technique. Bidirectional optical amplification is used in parallel with live traffic, and phase perturbations in the effective optical-fiber path length are compensated. This RF-over-fiber approach obviates the need for separate hydrogen masers at each antenna, offering significant advantages for radio-astronomy facilities such as the Square Kilometer Array.

Published
2018

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