Name: Tzioumis, Tasso
E-mail: Tasso.tzioumis@csiro.au
Affiliation: CSIRO
Type of presentation: Oral
Title: TBC
Abstract: TBD
Name: Karastergiou, Aris
E-mail: aris.karastergiou@physics.ox.ac.uk
Affiliation: Oxford
Type of presentation: Oral
Title: The true meaning of absolutely everything
Abstract: Testing
Name: Caleb, Manisha
E-mail: manisha.caleb@sydney.edu.au
Affiliation: University of Sydney
Type of presentation: None
Title:
Abstract:
Name: Zackay, Barak
E-mail: barak.zackay@weizmann.ac.il
Affiliation: Weizmann institute of Science
Type of presentation: Oral
Title: An algebraic solution to the timing problem
Abstract: I will present an algorithm capable of recovering (with a runtime measured in seconds) a full timing model for a pulsar given tens of phase measurements scattered over many years. This is useful for:
1) Automating the solution of the timing model of pulsars
2) Recovering new pulsars using Fermi-LAT data.
3) Searching for a possible fine-periodicity of FRBs
Name: Sara Elisa Motta
E-mail: sara.motta@inaf.it
Affiliation: INAF-Osservatorio Astronomico di Brera
Type of presentation: None
Title: NA
Abstract: NA
Name: Heywood, Ian
E-mail: ian.heywood@physics.ox.ac.uk
Affiliation: Oxford / Rhodes / SARAO
Type of presentation: Oral
Title: TBD
Abstract:
Name: Sappers, Ben
E-mail: ben.stappers@manchester.ac.uk
Affiliation: University of Manchester
Type of presentation: Oral
Title: Using Time Domain and Imaging Techniques on MeerKAT to characterise Fast Transients
Abstract: MeerTRAP is a project on the MeerKAT telescope which commensally looks for fast transients. By the time of this meeting it will have a good two years of time on sky and I'll summarise the technical capabilities of MeerTRAP and some of the highlights of its discoveries, including a couple of dozen FRBs, and a handful of super slow pulsars. I will also discuss the useful interplay with the parallel imaging data and some ideas for the SKA.
Name: Antoniadis, John
E-mail: john@ia.forth.gr
Affiliation: FORTH Institute of Astrophysics / MPIfR
Type of presentation: Oral
Title:
Abstract:
Name: Ng, Cherry
E-mail: cherry.ng@dunlap.utoronto.ca
Affiliation: Dunlap Institute for Astronomy and Astrophysics
Type of presentation: None
Title:
Abstract:
Name: Garrett, Michael
E-mail: michael.garrett@manchester.ac.uk
Affiliation: University of Manchester, Jodrell Bank Centre for Astrophysics
Type of presentation: None
Title:
Abstract:
Name: Possenti Andrea
E-mail: andrea.possenti@inaf.it
Affiliation: INAF-Osservatorio Astronomico di Cagliari
Type of presentation: Oral
Title: Pulsars and FRBs at the SKA Regional Centres: perspectives and desires
Abstract: SKAO will deliver hundreds of PBy of pulsar and FRB
data during the first few years of activity. The advanced analysis of those data will be conducted within a network of so-called SKAO Regional Centres (SRCs), which will also have the responsability to cure and archive both the original data and the advanced data products. The expected overall
capability of the SRC network will be around 20-30 Pflops, which opens unprecedented opportunities for post-processing and data analysis of pulsar and FRB data. A proto-SRC network is expected to be in place in a 2-3 yr timescale, likely focusing on both simulated and real data, the latter
mainly produced by the SKA precursors and pathfinders. A discussion about the best usage of the SRC activities is timely, since a refined tuning of requirements and specs is in course.
Name: Burke-Spolaor, Sarah
E-mail: Sarahbspolaor@gmail.com
Affiliation: West Virginia University
Type of presentation: Oral
Title: TBD
Abstract:
Name: Claudio Maccone
E-mail: clmaccon@libero.it
Affiliation: INAF (Italy) and IAA (Paris, France)
Type of presentation: Oral
Title: Moon Farside Protection for the benefit of Astronomy.
Abstract: Cosmology, Astrobiology, SETI and Planetary Defense will all benefit if we keep the Moon Farside free from man-made radio noise coming from Earth. But this Moon Farside Protection requires a United Nations Treaty as described in this 10-minutes video https://youtu.be/cF4rbOmMQnQ Please HELP the cause of Moon Farside Protection by supporting the actions of the newly-established Moon Farside Protection Permanent Committee of the IAA, that this author is chairing since December 2021.
Name: Nicolò Antonietti
E-mail: nicolo.antonietti@gmail.com
Affiliation: INAF-IRA
Type of presentation: Oral
Title:
Abstract:
Name: Eftekhari, Tarraneh
E-mail: teftekhari@northwestern.edu
Affiliation: Northwestern University
Type of presentation: Oral
Title: Extragalactic Millimeter Transients in the Era of Next Generation CMB Experiments
Abstract: The next generation of CMB surveys are poised to open a new window for transient discovery in the millimeter band. These surveys will cover a large fraction of the sky to unprecedented sensitivity and with high cadence, complementing existing wide-field radio and optical surveys. Using theoretical and empirical light curves for a wide range of extragalactic transients (including gamma-ray bursts, tidal disruption events, fast blue optical transients, neutron star mergers) in conjunction with known and estimated volumetric event rates, we explore the discovery phase space for millimeter transients in existing and near-term CMB surveys (ACT, SPT-3G, Simons Observatory, CMB-S4, CMB-HD). In each case, we use the CMB survey designs (area, depth, cadence, duration) to estimate detection rates and the resulting light curve characteristics. We find that CMB surveys will discover tens to hundreds of long-duration gamma-ray bursts (LGRBs), including the first large sample of reverse shock detections, facilitating detailed studies of the jet launching mechanism in LGRBs. Wide-field CMB surveys will also discover tens of fast blue optical transients, enabling the first unbiased sample of millimeter emission from these sources, and may detect up to several hundred tidal disruption events. Finally, we show that that the next decade of CMB experiments may detect a small number of short-duration gamma-ray bursts, which will be well within the detection volume of next generation gravitational wave experiments like Cosmic Explorer.
Name: Oleg Smirnov
E-mail: osmirnov@gmail.com
Affiliation: Rhodes University & SARAO
Type of presentation: Oral
Title: Invited talk TBD
Abstract: TBD :)
Name: Bannister, Keith
E-mail: keith.bannister@csiro.au
Affiliation: CSIRO
Type of presentation: Oral
Title: CRAFT Coherent Upgrade
Abstract: I will talk about how we're building a new FRB detector for the ASKAP that will search the full 30 deg^2 ASKAP field of view coherently for Fast Radio Bursts, searching roughly 20 Trillion pixels per second.
Name: Hughes, Andrew
E-mail: hughes1@ualberta.ca
Affiliation: University of Alberta
Type of presentation: Poster
Title: Time-Resolved Radio Polarimetry of V404 Cygni’s 2015 Outburst & Implications for SKA Pathfinders
Abstract: Accretion-powered relativistic jets are a ubiquitous element of systems with accreting black holes. Despite the ubiquity of these jets, we have yet to construct a complete picture of the underlying mechanisms that control their evolution. Due to synchrotron radiation being the primary emission mechanism of such jets, the resulting radio emission is partially linearly polarized, with a fractional polarization and polarization angle that depends on the local magnetic conditions. Thus, polarimetry can be used as a direct probe of the magnetic field, a component of the local environment that is currently thought to be a dominant factor in the launching and evolution of jets.
The temporal evolution of accretion-powered relativistic jets can be well probed using jets from black hole X-ray binaries (BHXBs; i.e., accreting stellar-mass black holes) as they have complete evolutionary cycles for their accretion flows and jets that only last days to years. In 2015 the BHXB V404 Cygni was detected as it entered an extremely luminous outbursting state. Follow-up radio observations taken with the Very Large Array (VLA) uncovered multiple bright flaring events. Furthermore, simultaneous observations with the Very Long Baseline Array (VLBA) conclusively revealed that the jet axis was processing, and the emission originated from both resolvable jet ejecta and an unresolved compact core. In this work we expand the previous analysis of V404 Cygni to include a time-resolved investigation of the linear polarization VLA data, constituting one of the most rapid cadence studies of radio polarimetry in BHXBs to date. Here, we present how the short timescale polarized variability (~15 minutes) that we detected evolves in both both frequency and time. We also discuss scientific and technical implications of such variability for other SKA pathfinders and Phase 1 of the SKA itself.
Name: van der Horst, Alexander
E-mail: ajvanderhorst@gwu.edu
Affiliation: The George Washington University
Type of presentation: Oral
Title: TBD (invited)
Abstract: TBD
Name: Atri, Pikky
E-mail: atri@astron.nl
Affiliation: ASTRON, the Netherlands
Type of presentation: Oral
Title: High-resolution imaging to unearth black hole birth mechanisms
Abstract: Accreting X-ray binaries are excellent laboratories to study extreme physics in our universe and provide unique opportunities to understand exotic neutron stars and black holes. It is thought that black hole X-ray binaries are small-scale Active Galactic Nuclei whose radio jets vary on human timescales. High-resolution radio imaging and astrometry are powerful tools that allow us to directly probe the evolution of these jets. In this talk, I will review the study of compact X-ray binaries and how Very Long Baseline Interferometry is enabling exciting breakthroughs in understanding their birth, evolution and advancing the search for new X-ray binary systems.
Name: Rammala Isabella
E-mail: isabella.rammala@gmail.com
Affiliation: Rhodes University
Type of presentation: Oral
Title: Classifying the MeerKAT Galactic Centre Compact Objects
Abstract: I will present the compact radio catalogue from the 1.28 GHz MeerKAT Galactic Center Mosaic images as well as pointing out some of the interesting sources in the catalogue.
Name: Maan, Yogesh
E-mail: ymaan@ncra.tifr.res.in
Affiliation: National Centre for Radio Astrophysics (NCRA - TIFR), India
Type of presentation: Oral
Title: Identifying the true nature of compact, steep spectrum sources
Abstract: Sensitive all sky imaging surveys have been uncovering interesting new sources, including compact sources with steep spectra that are strong candidates for interesting galactic as well as extra-galactic objects. A good fraction of the steep spectrum sources that are of Galactic origin are expected to be radio pulsars, some of which potentially also as parts of exotic binary systems or surrounded by dense environments. There are also clues adding up to the possibility that some of these sources might constitute a new, earlier unknown Galactic population of sources. Previous studies of steep spectrum sources have successfully uncovered exciting extra-galactic sources too, e.g., high-redshift radio galaxies with redshifts (z) as high as 5.7. Some of the steep spectrum sources might also be 'dead' or remnant radio galaxies. Identifying the true nature of these compact, steep spectrum sources requires a multitude of observing efforts, often amounting to interferometric characterization at a range of spatial resolution scales and radio pulsation searches in the beam-formed data at a wide range of frequencies. I will present characterization of a sample of more than 40 such sources in the Galactic plane using interferometric observations with the SKA pathfinder GMRT, time-domain searches for radio pulsations covering the frequency range 300 MHz - 5 GHz using multiple telescopes, and very high-resolution probes with the European VLBI Network (EVN). In addition to uncovering interesting exotic sources, such characterization at a larger, population scale will enable efficient searches for interesting sources, such as exotic pulsars and high-redshift galaxies, using samples selected from the imaging surveys in the SKA era.
Name: Marcote, Benito
E-mail: marcote@jive.eu
Affiliation: Joint Institute for VLBI ERIC (JIVE)
Type of presentation: Oral
Title: Precise localizations of Fast Radio Bursts and their local environments
Abstract:
Name: Stinebring, Dan
E-mail: dan.stinebring@oberlin.edu
Affiliation: Oberlin College
Type of presentation: Oral
Title: Time-variable scattering delays in pulsar timing: detection and mitigation strategies
Abstract: (to be refined) Time-variable scattering delays are the largest unmodeled component of most high-precision timing programs. Various PTAs, and other high-precision timing efforts, use a variety of strategies including the well-known "wish and a prayer" to cope with this source of noise -- and, to others, signal! -- in our data. I will summarize recent progress in this area, (probably) concentrating on cyclic spectroscopy (CS) methods being developed by NANOGrav in association with a new CS spectrometer being built at the Green Bank Observatory.
Name: Fender, Rob
E-mail: rob.fender@physics.ox.ac.uk
Affiliation: University of Oxford
Type of presentation: Oral
Title: (not sure yet)
Abstract: I can review transients work prospects with SKA, drawing on experience from ThunderKAT over the past 3+ years.
Name: Oswald, Lucy
E-mail: lucy.oswald@physics.ox.ac.uk
Affiliation: University of Oxford
Type of presentation: Oral
Title: Understanding radio pulsars in the 2020s
Abstract: Since their discovery in 1967, pulsars have been used to push the boundaries of our understanding of the Universe, through precision tests of General Relativity and the search for gravitational waves. Despite this, there remain many unanswered questions about the behaviour of pulsars themselves. In recent years however, new and upgraded telescopes have given us a broad-band perspective of pulsar radio emission. Broad-band observations enable us to separate intrinsic pulsar emission behaviour from the observational effects of propagation through the interstellar medium, allowing us to increase our understanding of both pulsars and their environments. I will present some new insights that these broad-band observations bring to our understanding of radio pulsars, focusing on the radio beam structure, pulsar polarization behaviour and the properties of scattering screens in the interstellar medium.
Name: Rhodes, Lauren
E-mail: lauren.rhodes@physics.ox.ac.uk
Affiliation: Oxford, UK; MPIfR, Germany
Type of presentation: Oral
Title: Radio afterglows of Very High Energy Gamma-ray Bursts
Abstract: Five long gamma-ray bursts (GRBs) have been found to have very high energy (VHE, >100GeV) counterparts. Interestingly, more than one emission mechanism has been invoked to explain the VHE counterpart from different events. As a result of this discovery, it has become apparent that we have been missing half of the energy produced in the afterglow of GRBs. We have been studying the radio afterglows in order to investigate whether these VHE GRBs have unusual jet and environment properties. Based on the current, limited sample, the jet properties and environments of these GRBs vary hugely in a similar manner to that seen in the ‘regular’ long GRB population with evidence of bright reverse shock emission and multiple jet components. This work is presented on behalf of a much larger collaboration.
Name: Li, Di
E-mail: dili@nao.cas.cn
Affiliation: National Astronomical Observatories, Chinese Academy of Sciences
Type of presentation: Oral
Title: Toward a statistical view of repeating pulses from active FRBs
Abstract: Designed to rival the point-source sensitivity of SKA1 with filled aperture, the FAST telescope has limited field of view, but has been productive in monitoring active FRBs. FAST has obtained sets of pulses numbered in thousands, for FRB 121102 and FRB 20201124A. FAST has discovered and accumulated hundreds of pulses for FRB 20190520B. In conjunction with GBT, Parkes, and Effelsberg, our multi-band monitoring efforts are starting to review key characteristics of active FRBs. The lack of RM detection at lower frequency bands (L-band by FAST, Chime band, etc) can be well explained by RM scatter, for example. These data sets start to quantify repeaters' behaviours with statistical significance. Combined analysis of the power, pulse shape (drift, etc), polarization, and scattering are building an evolutionary picture for active FRBs.
Name: Ray Norris
E-mail: raypnorris@gmail.com
Affiliation: WSU & CSIRO
Type of presentation: Oral
Title: Understanding Odd Radio Circles with ASKAP and Meerkat
Abstract: One of the unexpected discoveries from ASKAP were the Odd Radio Circles (ORCs) which are rings of radio emission, hundreds of kpc in diameter, surrounding galaxies at high redshifts. We have found ASKAP the premium instrument for finding them, and Meerkat the premium instrument for follow-up observations. A critical clue to their nature is the compact radio strcutre surrounding the host galaxy.
Name: Simon Johnston
E-mail: simon.johnston@csiro.au
Affiliation: CSIRO
Type of presentation: Oral
Title: Geometry of Pulsars
Abstract: We have observed 1200 pulsars with the MeerKAT telescope. What can this dataset tell us about the geometry of pulsars, the shape of the radio beam and the evolution of pulsar profiles with time?
Name: Posselt, Bettina
E-mail: bettina.posselt@physics.ox.ac.uk
Affiliation: University of Oxford
Type of presentation: Oral
Title: Does RX J0806.4-4123 spin up or spin down?
Abstract: The radio-quiet isolated neutron star RX J0806.4-4123 is associated with unique extended near-infrared emission, detected by the Hubble Space Telescope. One possible explanation for the infrared emission is a surrounding disk made of supernova fallback material. RX J0806.4-4123 is a slowly rotating (P~11s), thermal X-ray source and a member of the so-called Magnificent Seven (Mag7), a distinct group of neutron stars that are located between the magnetars and rotation-powered radio pulsars in the period--period-derivative diagram. An accurate timing solution of RX J0806.4-4123 can clarify whether this neutron star is different from its Mag7 siblings. I will present our multi-year X-ray timing campaign of RX J0806.4-4123 with the NICER instrument and what we can learn from it about the changing spin of this pulsar.
Name: Lower, Marcus
E-mail: marcus.lower@csiro.au
Affiliation: CSIRO Space and Astronomy
Type of presentation: Oral
Title: How do young pulsars spin-down over time?
Abstract: Conventionally, pulsars are thought to spin-down smoothly over time due to various radiative processes. However, long-term pulsar timing observations have revealed a more complex story. Many pulsars exhibit stochastic irregularities in their rotation over long timescales, often referred to as timing noise, as well as rotational glitches in the form of sudden spin-up events. There is also a growing sample of young pulsars that appear to be undergoing anomalously rapid spin-down evolution that cannot be explained by standard radiative mechanisms. In this talk, I will provide an overview of how modern statistical inference techniques have been used to characterise the timing irregularities and braking torques of a large sample of young pulsars observed by the Parkes radio telescope over the past decade. I will discuss the impact glitches have had on the rotational evolution of these pulsars and the potential implications for neutron star internal dynamics.
Name: Limaye Pranav
E-mail: plimaye007@gmail.com
Affiliation: University of Bonn
Type of presentation: None
Title:
Abstract:
Name: Jayacumaar, Jaswant
E-mail: jaswant.jayacumaar@manchester.ac.uk
Affiliation: The University of Manchester
Type of presentation: None
Title:
Abstract:
Name: Tetarenko, Alex
E-mail: atetaren@ttu.edu
Affiliation: Texas Tech University
Type of presentation: Oral
Title: Spectral-timing of X-ray binaries: The long wavelength perspective
Abstract: One of the key open questions in high-energy astrophysics is understanding how black holes act as powerful cosmic engines, accreting large amounts of material and expelling matter in the form of relativistic jets. Time-domain observations now offer a promising new way to address this question. Through detecting and characterizing rapid flux variability in black hole X-ray binary systems across a wide range of frequency/energy bands, we can measure properties that are difficult, if not impossible, to measure by traditional imaging methods (e.g., size scales, geometry, jet speeds, the sequence of events leading to jet launching). While variability studies in the X-ray and optical/IR bands are a staple in the community, there are many challenges that accompany such studies at longer wavelengths. However, by combining recent advances in observing techniques (e.g., the unique ability of the VLA to operate in sub-array mode) and the availability of new computational tools, we can manufacture the data sets we need to overcome these challenges. In this talk, I will discuss exciting new results from fast radio timing observations of several X-ray binaries, highlighting how we can derive fundamental jet properties from time-series signals alone. Additionally, I will discuss a new global observing program aimed at obtaining more of these invaluable fast timing data sets, and the key role that next-generation instruments (e.g., SKA, ngVLA) will play in driving new discoveries through this science.
Name: Sett, Susmita
E-mail: 20014515@student.curtin.edu.au
Affiliation: PhD student
Type of presentation: Poster
Title: Methodologies to detect pulsars in high time resolution images using the Murchison Widefield Array
Abstract: Pulsars have been proven instrumental to explore a wide variety of physics and astrophysics, ranging from probing dense-matter physics to testing strong-field gravity. They have been studied extensively and actively over the last few decades. However, there are still areas of research such as, emission mechanism, propagation effects that have not been well explored yet. These areas of research can be better studied by using a larger sample of pulsars and hence it is useful to detect more of them.
At low frequencies, pulsars are useful in studying the propagation effects and spectral properties. However, searching for pulsars at low frequencies with traditional methods tends to be computationally expensive and time consuming. This poster explores the interferometric and tied-array capabilities of the Murchison Widefield Array (MWA) to develop more efficient procedures that will employ imaging strategies in order to detect more of these objects. Using the unique capability of the MWA, the Voltage Capture System (VCS) which records high-time and frequency resolution voltage data (100 $\mu s$ / 10 kHz), we process the high time resolution data to produce continuum images which can then be used to test the image-based methodologies that we developed. The strategies developed exploit aspects such as spectral index, polarisation, variability and scintillation. We discuss the results obtained on implementation of these strategies to our data and the promising pulsar candidates obtained. As pulsar science, in particular timing applications using millisecond pulsars and binaries, is a key science driver for the Square Kilometre Array (SKA), establishing the strategies will not only help in accelerating the efforts of pulsar searching with the MWA but also in determining the future yield of pulsar surveys with the upcoming SKA.
Name: Parthasarathy, Aditya
E-mail: adityapartha3112@gmail.com
Affiliation: MPIfR
Type of presentation: Oral
Title: A gamma-ray pulsar timing array constrains the nanohertz gravitational wave background
Name: van der Wateren, Emma
E-mail: wateren@astron.nl
Affiliation: ASTRON / Radboud Universiteit
Type of presentation: Poster
Title: The properties of the pulsars discovered by the LOFAR Tied-Array All-Sky Survey
Abstract: In this talk, I will give an overview of the survey strategy and the findings from the LOFAR Tied-Array All-Sky Survey (LOTAAS), which so far has discovered 73 radio pulsars and redetected 311 previously known pulsars. The long integration times of this survey, which covers the full Northern hemisphere, improve the sensitivity to long-period pulsars. This resulted in the discovery of the 23.5-s pulsar, one the slowest-spinning radio pulsars known. The rotational parameters of PSR J0250+5854 put the pulsar beyond the conventional death line, where no radio emission is expected to be generated. We compared the properties of the LOTAAS discoveries with those of the rest of the pulsar population. Amongst the findings, we find that pulsars discovered by LOTAAS have on average longer spin periods and lower spin-down rates than the known pulsar population, placing them closer to the death line. We are exploring whether this is a real effect or due to selection bias.
Name: van der Wateren, Emma
E-mail: wateren@astron.nl
Affiliation: ASTRON / Radboud Universiteit
Type of presentation: Oral
Title: The properties of the pulsars discovered by the LOFAR Tied-Array All-Sky Survey
Abstract: In this talk, I will give an overview of the survey strategy and the findings from the LOFAR Tied-Array All-Sky Survey (LOTAAS), which so far has discovered 73 radio pulsars and redetected 311 previously known pulsars. The long integration times of this survey, which covers the full Northern hemisphere, improve the sensitivity to long-period pulsars. This resulted in the discovery of the 23.5-s pulsar, one the slowest-spinning radio pulsars known. The rotational parameters of PSR J0250+5854 put the pulsar beyond the conventional death line, where no radio emission is expected to be generated. We compared the properties of the LOTAAS discoveries with those of the rest of the pulsar population. Amongst the findings, we find that pulsars discovered by LOTAAS have on average longer spin periods and lower spin-down rates than the known pulsar population, placing them closer to the death line. We are exploring whether this is a real effect or due to selection bias.
Name: Matthew Kerr
E-mail: matthew.kerr@gmail.com
Affiliation: US Naval Research Laboratory
Type of presentation: Oral
Title: The Stability of Young Pulsar Magnetospheres
Abstract: Radio pulsars have a rich phenomenology of variability which is now known to be associated with major changes of the magnetosphere and global energy-loss rate. Modern particle-in-cell simulations also support the idea that such magnetospheric re-configuration is widespread. However, of the nearly 300 gamma-ray pulsars detected by the Fermi Large Area Telescope, only one has been found to vary!
This puzzle may have a simple solution: no one has systematically searched for variability. Even the brightest pulsars spin thousands of times before a single one of their photons is caught by the LAT, so special techniques are needed to characterize fast variability. We have developed such techniques and are searching the entire gamma-ray population for variability on timescales from milliseconds to years. We will present preliminary results from our search and show that they provide strong constraints on mode changing in gamma-ray pulsar magnetospheres.
Name: Jiwoong Jang
E-mail: jjang@mpifr-bonn.mpg.de
Affiliation: Max-Planck Institute für Radioastronomie
Type of presentation: Oral
Title: Constraining the orbital parameters of PSR J1439-5501 using a first detection of Shapiro delay and scintillation
Abstract: The pulsar-white dwarf binary, J1439-5501, was first discovered in the Parkes Multibeam survey (Faulkner et al. 2004 and Lorimer et al. 2006) in a circular orbital with a period of 2.12 days. In 2013 Pallanca et al. were able to detect the white dwarf in the optical and constrained the mass range to be 1-1.3 MSun based on white dwarf cooling models.
This work presents the results of a timing campaign using the MeerKAT telescope combined with the earlier Parkes data. The considerable increase in sensitivity has allowed the Shapiro delay to be detected for the first time, providing a measurement of the white dwarf mass and inclination angle of the orbit. When combined with the Chandra Shekhar mass limit, this gives a companion mass of 1.27(+8, -23) Msun, a pulsar mass of 1.57(+22,-47) Msun, and an inclination angle of 77.3(+1,-2) deg.
The strong scintillation seen in the pulsar also allowed the longitude of ascending node and the orientation, velocity and distance to the screen to be measured when combined with the timing results. The scintillation results also suggest that the distance is 1.0(2) kpc, which is well above the DM derived distance of 603-655 pc (YMW, NE2001), and at the upper end of the optical estimation of 650-1200 pc.
A measurement of Pbdot would provide a significant improvement in the constraint of the masses in the system. Simulations based on the current timing precision, expected upgrades to MeerKAT, and eventually using the SKA, suggest that Pbdot should be measurable in approximately 2028.
Name: Kelly Gourdji
E-mail: kgourdji@swin.edu.au
Affiliation: Swinburne University of Technology
Type of presentation: Oral
Title: LOFAR observations of neutron star mergers
Abstract: Both coherent and incoherent low-frequency radio emission are predicted at various timescales when neutron stars coalesce. In this talk, I show how the Low-Frequency Array (LOFAR) is being used to catch both fast and slow radio transients related to neutron star mergers.
At the earliest timescales, coherent emission resembling FRBs is predicted by several theoretical models. Testing these models requires rapid triggered observations. We use LOFAR’s rapid response mode to trigger on short gamma-ray bursts (SGRBs) detected by Swift, which have neutron star merger progenitors. This enables us to be on source within minutes and to probe early-time coherent emission at unprecedented sensitivity. Here, I present our strategy and latest results using joint LOFAR and Swift X-ray and gamma-ray data.
In addition to possible prompt emission, there will be a long-lasting synchrotron afterglow caused by the merger ejecta’s interaction with the ambient medium. The biggest challenge associated with detecting the electromagnetic counterpart of gravitational wave (GW) merger events, however, is the large uncertainty (tens of square degrees) on their locations. Here, we present our strategy which applies LOFAR’s high sensitivity and large field of view to search for GW merger radio counterparts. In particular, using state-of-the-art data reduction techniques, we obtain radio maps covering 21 deg^2 with rms noise levels down to 0.2 mJy on epochs ranging from 1 week to months post-merger. We present our results from LOFAR follow-up observations of three merger events from the last GW observing run. We also show how the high sensitivity, large field of view and range of epochs permit us to probe previously unexplored parts of general radio transient phase space. Finally, the wide coverage of our observations should probe most of the localization region for binary neutron star merger events detected in the next GW observing run.
Name: Marisa Geyer
E-mail: mgeyer@sarao.ac.za
Affiliation: SARAO
Type of presentation: Oral
Title: Characterising the masses in MeerKAT relativistic binaries - a tale of two systems
Abstract: The abstract is a work in progress, but something along these lines:
In this talk I will demonstrate MeerKATs power in extracting accurate mass measurements from two relativistic binary systems, and consider what it teaches us about their evolutionary histories.
Pulsar J0955-6150 is a binary system with a curious past. These days it is found in a highly elongated orbit with a Helium White Dwarf, but how did it get there? Adding MeerKAT data to decade old Parkes data we improve on the accuracy of the mass measurements of both the pulsar and its White Dwarf companion. While the pulsar mass is found to be within the anticipated range, the White Dwarf weighs in at an unexpectedly low value … tipping the scale in favour of a new and as of yet unexplored formation path.
The scintillating PSR J1933-6211 too has escaped accurate mass measurements until MeerKAT stepped in. Again combining MeerKAT data with Parkes data, we conduct full polarisation timing; perform a detailed noise analysis and computed the kinematic contributions to the system’s timing parameters to finally provided clear-cut evidence on the nature of its orbiting companion — solving the literature mystery of a potentially too-light-to-believe pulsar.
Name: Surnis, Mayuresh
E-mail: msurnis@gmail.com
Affiliation: JBCA, University of Manchester
Type of presentation: Oral
Title: MeerKAT Localisation of Radio Transients Discovered with MeerTRAP
Abstract: Radio transient searches have traditionally been carried out through observations with single dish telescopes. Radio surveys with interferometers have the potential to localise the newly discovered transients through high-time resolution imaging. MeerTRAP is a real-time transient search instrument on MeerKAT that operates in a commensal mode with the large survey projects. This provides a unique way of searching for radio transients through a large amount of on-sky time as well as with repeated visits for some particular fields. MeerTRAP has the capability of saving data buffers containing the transient event through triggered buffer dumps. These can be used for offline localisation through interferometric imaging. In this talk, I will describe the localization of some of the transients using the interferometric and the tied-array beam localisation methods. I will talk about the importance of interferometric localisation for one-off fast radio bursts as well as extremely intermittent radio pulsars. I will also discuss the importance of radio imaging in providing important input for future surveys with interferometers.
Name: Nimmo, Kenzie
E-mail: k.nimmo@uva.nl
Affiliation: ASTRON/University of Amsterdam
Type of presentation: Oral
Title: Linking fast radio bursts to young pulsars through timescales and luminosities
Abstract: The recording of raw voltage data in fast radio burst (FRB) observations provides the opportunity to study the burst properties in extremely high detail, which contains valuable clues into the burst progenitor and emission physics. By studying the burst properties at the highest time and frequency resolution possible, as well as the polarisation properties, we can apply constraints on the FRB emission mechanism and find similarities with known Galactic sources of radio bursts. In this talk, I will present the high-time-resolution spectropolarimetry study of two FRB sources, FRB 20180916B and FRB 20200120E, using data from the Effelsberg telescope during a localisation campaign with the European VLBI Network. We find temporal structure with widths as narrow as a few microseconds in FRB 20180916B, which is at the limit due to scattering from the Milky Way interstellar medium. FRB 20200120E, however, is at a much higher Galactic latitude, meaning instead we are limited by the data itself. We measure isolated shots of emission approximately 60 nanoseconds in duration, from FRB 20200120E, with brightness temperatures ~ 10^41 K, comparable to the brightest nano-shots from the Crab pulsar. Additionally, in both sources we see a range of timescales that span three orders of magnitude, and consistent polarisation properties that match what is seen from the first repeater, FRB 121102. I will discuss these results in the context of FRB models, and link to studies of the Crab pulsar and the Galactic magnetar SGR 1935+2154. Additionally, I will discuss the limitations of such studies, from propagation effects to instrumental challenges, and highlight a relatively unexplored parameter space of ultra-fast radio bursts.
Name: Vleeschower Calas, Laila
E-mail: laila.vleeschowercalas@postgrad.manchester.ac.uk
Affiliation: University of Manchester
Type of presentation: Oral
Title: Pulsar survey of Globular Clusters using MeerKAT
Abstract: A new phase of pulsars discovered in globular clusters has started thanks primarily to the FAST and MeerKAT telescopes. Using the South African MeerKAT radio telescope we have conducted searches for new pulsars in globular clusters (GCs), which are known to be ideal places for the formation of millisecond pulsars (MSPs) due to their high stellar densities in their cores ($\sim$ 10$^{5-6}$\,\msun pc$^{-3}$) inducing dynamical interactions between stars. A total of 40 pulsars have been found in the sixteen clusters searched so far. In this talk I will focus on the most recent discoveries made, which includes a wide range of pulsars, which goes from slow isolated MSPs (e.g. NGC 6441E) to binaries with extremely eccentric (e > 0.7) orbits (e.g. NGC 1852D) and the pulsar with the lightest companion known so far (NGC 6440H).
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