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Showing results for: [ Astronomical and Space Sciences not elsewhere classified ]
Fast radio bursts (FRBs) continue to raise more questions than they answer. Until last year, only one burst – the only one known to repeat - had been localized to a bright radio nebula (either a youn... moreg supernova remnant or pulsar wind nebulae) in a distant dwarf galaxy. Over the last two year searches with the Australian Square Kilometre Array Pathfinder (ASKAP) have detected 31 bursts, five of which have been localised to host galaxies at redshifts ranging from 0.1 to 0.5. These bursts and their hosts are very unlike the repeater, suggesting there may be a dichotomy in the population. However one of the arcminute-localised ASKAP FRBs has recently been found to repeat. Here we propose to search and study repetitions in this FRB population. Our comprehensive sample and a dense monitoring campaign of well localised bursts, at a fluence limit more than 60 times lower than that of their detections to characterise the fraction of bursts that repeat. For bursts that repeat the unique wide bandwidth observations will be used to test leading models of burst emission.less
Australia Telescope National Facility - P958 - Searching for repetition from ASKAP fast radio bursts - Published 10 Dec 2019
We request time to observe 260 pulsars on a regular basis to provide the accurate ephemerides necessary for the detection and characterisation of gamma-ray pulsars with the Fermi satellite. The primar... morey science goals are to increase the number of known gamma-ray pulsars (both radio loud and radio quiet), to determine accurate pulse profiles, and to characterise their high energy (phase-resolved) spectra. In the radio, the observations will also allow us to investigate: neutron stars and pulsar emission via detecting glitches and determining pulse timing parameters; and the ISM via measuring and monitoring dispersion measures, Faraday rotation measures, and scintillation. To date, we are (co-)authors on 75 papers arising from the collaboration and P574 data. The data have contributed to the PhD theses of students from Bordeaux, Manchester, Oxford, Stanford, and Swinburne.less
Australia Telescope National Facility - P574 - Pulsar timing and the GLAST mission - Published 03 Dec 2019
Australia Telescope National Facility - P958 - Searching for repetition from ASKAP fast radio bursts - Published 03 Dec 2019
Australia Telescope National Facility - P958 - Searching for repetition from ASKAP fast radio bursts - Published 29 Nov 2019
Australia Telescope National Facility - P958 - Searching for repetition from ASKAP fast radio bursts - Published 26 Nov 2019
Neutron stars are composed of the densest form of matter known to exist in our universe, and thus provide a unique laboratory for exploring supra-nuclear densities. We propose timing observations of ... morea super-massive pulsar, PSR J1748?2021B, that resides in a binary system in the NGC6440 globular cluster. This pulsar is potentially the most massive pulsar known, and hence can constrain/rule out several Neutron Star (NS) equation of states proposed so far. The mass measurement is currently limited by our detection significance of the Shapiro delay. Hence, we are aiming at a dense orbital campaign for this system with Parkes and MeerKAT telescopes to obtain precise estimates of the component masses of this binary system in the next 6-12 months.less
Australia Telescope National Facility - P1033 - Estimating the Shapiro delay in the binary pulsar system PSR J1748-2021B - Published 21 Nov 2019
Australia Telescope National Facility - P958 - Searching for repetition from ASKAP fast radio bursts - Published 20 Nov 2019
This proposal relates to time purchased by the Chinese Academy of Sciences for Parkes follow-up confirmation and timing of FAST discoveries. As the observing time has been purchased this proposal (an... mored the related PX500) does not require TAC grading. The primary reason for submitting a proposal is to ensure an outreach statement and that the proposal is entered into OPAL for the data archive to access. The Chinese team have two time requests. The time scheduled for the first (PX500) will be allocated in blocks of 24 hours and the data will become available in the data archive with an 18 month embargo period. The second type of time (relating to this proposal) will be scheduled in shorter blocks and the data archived with a 10 year embargo.less
Australia Telescope National Facility - PX501 - FAST: category 2 purchased time - Published 18 Nov 2019
We propose to observe the magnetars 1E 1547.0-5408 and PSR J1622-4950 approximately weekly, to track their rotation, flux density, and polarisation, as we have been doing through this project. Also,... more as of late 2018, XTE J1810-197 is again a radio magnetar after 10 years dormant! Its chaotic rotation is better tracked in detail elsewhere, but weekly observations with the UWL receiver are already providing unique measurements of its radio spectrum and broad-band behaviour. Our observations provide an important window into remarkably dynamic magnetar magnetospheres, and characterise the conditions under which radio emission takes place therein, placing constraints on the emission mechanisms, which in at least some significant respects differ from those of ordinary pulsars.less
Australia Telescope National Facility - P885 - Understanding the Remarkable Behaviour of Radio Magnetars - Published 17 Nov 2019
The Parkes Pulsar Timing Array (PPTA) project has three primary goals: (a) detection of gravitational waves from astronomical sources, (b) establishment of a pulsar timescale, and (c) improvement of o... moreur understanding of Solar-system dynamics. The PPTA is the oldest of three international pulsar timing groups. We have the smallest telescope and the smallest group, but the best measurements and the best results. Our bound on the strength of the incoherent gravitational wave background is the only bound which significantly constrains theoretical models. We have maintained our leading position because: we have the southern sky; we have a small but well-focussed group; we have the best-calibrated receivers; and we have been able to observe with an almost regular cadence of 15 to 20 days over a wide bandwidth. With this proposal we aim to maintain our pre-eminent position in the field. Unlike most observing proposals, this is a continuing proposal for which the observations will continue to improve bounds on ultra-low-frequency gravitational waves until they are finally detected. Continued Parkes observations will remain valuable at least until the first stage of the SKA is able to improve on our sensitivity and observing cadence. Even after the gravitational wave background is detected we will want to continue observations in support of the nascent field of gravitational wave astronomy!less
Australia Telescope National Facility - P456 - A millisecond pulsar timing array - Published 17 Nov 2019
Australia Telescope National Facility - P958 - Searching for repetition from ASKAP fast radio bursts - Published 16 Nov 2019
Recently there has been great success at Parkes discovering millisecond pulsars (MSPs), a class that includes some of the most interesting and scientifically valuable pulsars known. In the last few ye... morears, we have discovered more than 40 MSPs though the High Time Resolution Universe Survey (P630) and Fermi searches (P675/P814). Here we propose to carry out precision timing of these sources to fully exploit these discoveries. Additionally, we continue to study the most significant of the discoveries from the Parkes Multibeam Pulsar Survey (P268). To maximise scientific impact, we have combined the most important sources from various previous proposals into this project, reducing total observation time required and easing the burden on the scheduler.less
Australia Telescope National Facility - P789 - Timing of Binary & Millisecond Pulsars Discovered at Parkes - Published 16 Nov 2019
We recently discovered two millisecond pulsars (MSPs) in the globular cluster, Omega Centauri, the first pulsar discovery in this globular cluster. The discovery of these MSPs will enable us to study ... morethe stellar population and dynamics in the core of Omega Centauri, and to probe the ionised interstellar medium in Omega Centauri. These two MSPs are potentially in extreme eclipsing systems, and are useful for us to understand the formation of such systems. More importantly, our discoveries, for the first time, allow us to carry out a deep, coherently de-dispersed, high time resolution survey of pulsars in Omega Centauri, which might lead to exciting discoveries. We propose to carry out follow-up timing observations of the new discoveries, and a new coherently de-dispersed, high time resolution survey of Omega Centauri.less
Australia Telescope National Facility - P1034 - Follow-up of the first millisecond pulsar discoveries in Omega Centauri and a new coherently de-dispersed survey - Published 16 Nov 2019
We propose to carry out Parkes follow-up observations of the new millisecond pulsar, J1431-6328, discovered by the Australian SKA Pathfinder (ASKAP) and Parkes Ultra-Wideband Low (UWL) receiver. The d... moreiscovery demonstrated the power of identifying pulsar candidates in radio continuum images and then following up with high time resolution observations. The discovery itself is also interesting. PSR J1431-6328 has a spin period of 2.77 ms, and is likely to be in a binary system. Follow-up observations will enable us to measure the binary parameters, which will guide future multi-wavelength observations and might shed new lights on the binary evolution. The short spin period, relatively large flux density and sky location of PSR J1431-6328 also make it a promising candidate for pulsar timing arrays. The proposed observations will allow us to obtain a timing solution of this new pulsar, and are therefore essential for future timing observations.less
Australia Telescope National Facility - P1027 - Follow-up of the ASKAP discovery of millisecond pulsar J1431-6328 - Published 15 Nov 2019
We propose to conduct observations of PSR J1653-45, a 951-ms pulsar in a long, 1.5-yr orbit. Binary pulsars are valuable objects of scientific study, allowing for a wide range of applications, includi... moreng tests of gravity, probes of the neutron star equation of state, and fossil records of stellar evolution. Long spin-period pulsars in binary systems are generally much rarer than faster-spinning `recycled’ pulsars, and represent an under-explored region of pulsar binary evolution. In addition to its long orbital period, PSR J1653-45 also experiences extended eclipses, lasting up to half of the orbital period and whose nature is not well understood. These eclipses have also prevented the determination of an orbital of phase-connected timing solution, both vital steps in allowing for the continued study of this system. We propose a targeted, high-cadence observing campaign designed to monitor this pulsar as it transition into its eclipsing state. The campaign has the twin goals of both monitoring how the eclipse affects the pulsar’s emission properties, thereby revealed more about the nature of the eclipses themselves, and of extracting as much information regarding the pulsar’s orbit during its least-explored regions, thereby constrained and hopefully solving the pulsar’s orbit and ideally leading to the development of a timing solution. In both instances, we hope to gain a greater understanding of this pulsar’s properties and how it fits into this under-explored class of unrecycled pulsar binaries.less
Australia Telescope National Facility - P1021 - Mapping the orbit of an enigmatic 1.5-yr eclipsing binary pulsar. - Published 15 Nov 2019
We propose timing observations of southern double neutron star (DNS) systems to obtain precise estimates of the component masses and thus increase the statistics of neutron star mass distribution. Th... moree improved sensitivity of the Ultra Wideband Low (UWL) receiver will provide a 3X increase in the precision of the time of arrivals (ToAs) of the pulses compared to the multibeam data. This has the potential to perform quick measurements of masses for a number of binary systems in the next 1-2 years. We will also use MeerKAT observations at crucial orbital phases to increase our chances of mass measurements. Increase in the number of measured NS masses has significant implications for understanding NS internal structure and for stellar and binary evolution physics.less
Australia Telescope National Facility - P1032 - Mass measurements of southern binary pulsar systems - Published 15 Nov 2019
Since the year 2005, the Parkes Pulsar Timing Array (PPTA) project has been placing ever more stringent constraints on the amplitude of a gravitational wave background signal. Such upper bounds on th... moree amplitude of the gravitational wave signal are currently dominated by a single pulsar: PSR J1909-3744. The upper bound with this pulsar alone already cuts into the range of tenable theoretical models. Further reducing the amplitude bound (by continued regular observations of this pulsar) will significantly narrow that range. The first evidence of gravitational waves in the pulsar data are likely to be observed in the timing for PSR J1909-3744, but with only a single pulsar we will not be able to make an unambiguous detection. However, knowledge of the likely signal strength (derived from this pulsar) will help to optimise the observing strategy for the detection of the gravitational wave signals with existing or future pulsar timing arrays.less
Australia Telescope National Facility - P895 - Where are the gravitational waves? - Published 15 Nov 2019
Australia Telescope National Facility - PX501 - FAST: category 2 purchased time - Published 15 Nov 2019
Australia Telescope National Facility - P885 - Understanding the Remarkable Behaviour of Radio Magnetars - Published 15 Nov 2019
Australia Telescope National Facility - P958 - Searching for repetition from ASKAP fast radio bursts - Published 15 Nov 2019
We propose to continue the PULSE@Parkes project in which high school students from Australia and around the World use the Parkes radio telescope in a remote observing model to observe and analyse puls... morear data. The data from some PULSE@Parkes observations are used to support the FERMI Gamma ray mission, other observations supplement the P456 Pulsar Timing Array project and the remainder were chosen in order to make a detailed analysis of pulsar timing irregularities and intermittency.less
Australia Telescope National Facility - P595 - PULSE@Parkes (Pulsar Student Exploration at Parkes) - Published 14 Nov 2019
Australia Telescope National Facility - P958 - Searching for repetition from ASKAP fast radio bursts - Published 14 Nov 2019
Australia Telescope National Facility - P1021 - Mapping the orbit of an enigmatic 1.5-yr eclipsing binary pulsar. - Published 14 Nov 2019
Australia Telescope National Facility - P958 - Searching for repetition from ASKAP fast radio bursts - Published 13 Nov 2019
